National Management Measures 

to Control Nonpoint Source 

Pollution from Urban Areas
United States Environmental Protection Agency

Office of Water

Washington, DC 20460

(4503F)

EPA-841-B-05-004

November 2005
Table of Contents

Disclaimer 

This document provides guidance to States, Territories, authorized Tribes, and the public 

regarding management measures that may be used to reduce nonpoint source pollution from 

urban areas. This document refers to statutory and regulatory provisions which contain legally 

binding requirements. This document does not substitute for those provisions or regulations, nor 

is it a regulation itself. Thus, it does not impose legally-binding requirements on EPA, States, 

Territories, authorized Tribes, or the public and may not apply to a particular situation based 

upon the circumstances. EPA, State, Territory, and authorized Tribe decision makers retain the 

discretion to adopt approaches on a case-by-case basis that differ from this guidance where 

appropriate. Interested parties are free to raise questions and objections about the appropriateness 

of the application of the guidance to a particular situation, and EPA will consider whether or not 

the recommendations in this guidance are appropriate in that situation. EPA may change this 

guidance in the future. 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas

Table of Contents 

List of Figures.............................................................................................................................. xiv 

List of Tables ................................................................................................................................ xv 

0 Introduction............................................................................................................................ 0-1 

0.1 Purpose and Scope of the Guidance.............................................................................. 0-1 

0.1.1 Management Measures ..................................................................................... 0-3 

0.1.2 Document Organization.................................................................................... 0-5 

0.2 Origin and Regulatory Context..................................................................................... 0-6 

0.2.1 Origin of This Guidance ................................................................................... 0-6 

0.2.2 Regulatory Context ........................................................................................... 0-7 

0.3 Key Concepts.............................................................................................................. 0-12 

0.3.1 Watershed Approach....................................................................................... 0-12 

0.3.2 Stream Network .............................................................................................. 0-13 

0.3.3 Impervious and Pervious Surfaces in the Urban Landscape........................... 0-16 

0.3.4 Impervious Cover Model ................................................................................ 0-18 

0.3.5 Changes in the Watershed Due to Increased Imperviousness ........................ 0-21 

0.3.6 Nonpoint Source Pollutants and Their Impacts .............................................. 0-28 

0.3.7 Nonpoint Source Pollutant Loading................................................................ 0-35 

0.3.8 Other Impacts of Urban Runoff ...................................................................... 0-35 

0.3.9 Management Practices .................................................................................... 0-36 

0.4 Information Resources................................................................................................ 0-38 

0.5 References................................................................................................................... 0-40 

1 Management Measure 1: Program Framework and Objectives............................................. 1-1 

1.1 Management Measure................................................................................................... 1-1 

1.2 Management Measure Description and Selection......................................................... 1-1 

1.2.1 Description........................................................................................................ 1-1 

1.2.1.1 Role of federal government ............................................................... 1-1 

1.2.1.2 Role of state government ................................................................... 1-1 

1.2.1.3 Role of regional authorities................................................................ 1-2 

1.2.1.4 Role of local government................................................................... 1-2 

1.2.2 Management Measure Selection....................................................................... 1-4 

1.3 Management Practices .................................................................................................. 1-4 

1.3.1 Establish Legal Authority ................................................................................. 1-4 

1.3.1.1 Examine existing laws and regulations.............................................. 1-5 

1.3.1.2 Develop or improve ordinances for water quality enhancement ....... 1-8 

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1.3.1.3 Explore market-based regulatory approaches.................................. 1-15 

1.3.2 Develop an Institutional Structure .................................................................. 1-16 

1.3.2.1 Establish a watershed baseline......................................................... 1-16 

1.3.2.2 Set up an institutional structure........................................................ 1-21 

1.3.2.3 Determine budgetary resources available for watershed planning .. 1-23 

1.3.2.4 Project future land use change in the watershed/subwatershed ....... 1-24 

1.3.2.5 Develop subwatershed plan ............................................................. 1-25 

1.3.2.6 Adopt and implement the watershed plan........................................ 1-27 

1.3.2.7 Revisit and update the watershed and subwatershed plan ............... 1-27 

1.3.3 Provide Adequate Funding and Staffing......................................................... 1-27 

1.3.3.1 Taxes and fees.................................................................................. 1-28 

1.3.3.2 Bonds ............................................................................................... 1-29 

1.3.3.3 Leases............................................................................................... 1-30 

1.3.3.4 Intergovernmental transfers and assistance ..................................... 1-30 

1.3.3.5 Public-private partnerships .............................................................. 1-31 

1.3.4 Foster Input from Technical Experts, Citizens, and Stakeholders.................. 1-31 

1.3.4.1 Technical committees ...................................................................... 1-31 

1.3.4.2 Citizen committees........................................................................... 1-31 

1.3.4.3 Stakeholder committees................................................................... 1-32 

1.3.5 Establish Intergovernmental Coordination ..................................................... 1-33 

1.3.6 Develop Training and Education Programs and Materials............................. 1-34 

1.4 Information Resources................................................................................................ 1-36 

1.5 References................................................................................................................... 1-39 

2 Management Measure 2: Watershed Assessment.................................................................. 2-1 

2.1 Management Measure................................................................................................... 2-1 

2.2 Management Measure Description and Selection......................................................... 2-1 

2.2.1 Description........................................................................................................ 2-1 

2.2.2 Management Measure Selection....................................................................... 2-1 

2.2.2.1 Overview............................................................................................ 2-1 

2.2.2.2 Examples of monitoring and assessment programs and 

methodologies.................................................................................... 2-2 

2.3 Management Practices .................................................................................................. 2-3 

2.3.1 Characterize Watershed Conditions.................................................................. 2-3 

2.3.1.1 Establish a reference condition .......................................................... 2-3 

2.3.1.2 Model pollutant sources and loads..................................................... 2-4 

2.3.1.3 Model receiving water quality ........................................................... 2-8 

2.3.2 Assess Cumulative Effects.............................................................................. 2-10 

2.3.3 Estimate the Effectiveness of Treatment Programs........................................ 2-10 

2.3.4 Establish a Set of Watershed Indicators.......................................................... 2-12 

2.3.5 Establish Water Quality Indicators ................................................................. 2-13 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas

2.3.6 Establish Physical and Hydrological Indicators ............................................. 2-16 

2.3.7 Establish Biological Indicators ....................................................................... 2-18 

2.3.8 Establish Programmatic Indicators ................................................................. 2-22 

2.3.9 Develop a Suite of Social Indicators............................................................... 2-22 

2.4 Information Resources................................................................................................ 2-23 

2.5 References................................................................................................................... 2-27

3 Management Measure 3: Watershed Protection .................................................................... 3-1 

3.1 Management Measure................................................................................................... 3-1 

3.2 Management Measure Description and Selection......................................................... 3-1 

3.2.1 Description........................................................................................................ 3-1 

3.2.2 Management Measure Selection....................................................................... 3-2 

3.3 Management Practices .................................................................................................. 3-3 

3.3.1 Resource Inventory and Information Analysis ................................................. 3-3 

3.3.1.1 Identify environmentally sensitive, critical conservation areas......... 3-4 

3.3.1.2 Identify and protect drinking water sources....................................... 3-5 

3.3.2 Development of Watershed Management Plan................................................. 3-7 

3.3.3 Implement the Plan ........................................................................................... 3-9 

3.3.3.1 Develop ordinances or regulations requiring nonpoint source 

pollution controls for new development and redevelopment............. 3-9 

3.3.3.2 Plan infrastructure.............................................................................. 3-9 

3.3.3.3 Revise local zoning ordinances........................................................ 3-10 

3.3.3.3.1 Performance-based zoning............................................. 3-11 

3.3.3.3.2 Overlay zones................................................................. 3-11 

3.3.3.3.3 Bonus or incentive zoning ............................................. 3-11 

3.3.3.3.4 Large-lot zoning............................................................. 3-12 

3.3.3.3.5 Farmland preservation zoning........................................ 3-12 

3.3.3.3.6 Watershed-based zoning ................................................ 3-13 

3.3.3.3.7 Urban growth boundaries............................................... 3-14 

3.3.3.4 Establish limits on impervious surfaces, encourage open space, 

and promote cluster development .................................................... 3-15 

3.3.3.5 Revitalize existing developed areas................................................. 3-16 

3.3.3.6 Establish setback (buffer zone) standards........................................ 3-16 

3.3.3.6.1 Buffer ordinance ............................................................ 3-18 

3.3.3.6.2 Vegetative and use strategies within management 

zones .............................................................................. 3-19 

3.3.3.6.3 Provisions for buffer crossings ...................................... 3-19 

3.3.3.6.4 Integration of structural runoff management practices 

where appropriate........................................................... 3-19 

3.3.3.6.5 Development of buffer education and awareness 

programs ........................................................................ 3-20 

3.3.3.7 Establish slope restrictions............................................................... 3-20 

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3.3.3.8 Promote urban forestry .................................................................... 3-20 

3.3.3.9 Use site plan reviews and approval.................................................. 3-21 

3.3.3.10 Designate an entity or individual responsible for maintaining the 

infrastructure, including urban runoff management systems........... 3-22 

3.3.3.11 Use official mapping........................................................................ 3-22 

3.3.3.12 Require environmental impact assessment statements .................... 3-22 

3.3.4 Cost of Planning Programs ............................................................................. 3-22 

3.3.5 Land or Development Rights Acquisition Practices....................................... 3-23 

3.3.5.1 Fee simple acquisition/conservation easements............................... 3-24 

3.3.5.2 Leases, deed restrictions, and covenants.......................................... 3-24 

3.3.5.3 Transfer of development rights........................................................ 3-25 

3.3.5.4 Purchase of development rights....................................................... 3-27 

3.3.5.5 Land trusts........................................................................................ 3-27 

3.3.5.6 Agricultural and forest districts ....................................................... 3-27 

3.3.5.7 Cost and effectiveness of land acquisition programs....................... 3-27 

3.4 Information Resources................................................................................................ 3-29 

3.5 References................................................................................................................... 3-33 

4 Management Measure 4: Site Development.......................................................................... 4-1 

4.1 Management Measure................................................................................................... 4-1 

4.2 Management Measure Description and Selection......................................................... 4-1 

4.2.1 Description........................................................................................................ 4-1 

4.2.2 Management Measure Selection....................................................................... 4-3 

4.3 Management Practices .................................................................................................. 4-3 

4.3.1 Site Planning Practices...................................................................................... 4-5 

4.3.1.1 Select site designs that preserve or minimize impacts to 

predevelopment site hydrology and topography................................ 4-5 

4.3.1.2 Protect environmentally sensitive areas............................................. 4-5 

4.3.1.3 Practice site fingerprinting................................................................. 4-6 

4.3.1.4 Use cluster development.................................................................... 4-6 

4.3.1.5 Create open space .............................................................................. 4-8 

4.3.2 On-Lot Impervious Surfaces........................................................................... 4-16 

4.3.2.1 Reduce the hydraulic connectivity of impervious surfaces ............. 4-16 

4.3.2.2 Practice rooftop greening................................................................. 4-18 

4.3.2.3 Relax frontage and setback requirements ........................................ 4-22 

4.3.2.4 Modify sidewalk standards .............................................................. 4-22 

4.3.2.5 Modify driveway standards.............................................................. 4-23 

4.3.3 Residential Street and Right-of-Way Impervious Surfaces ............................ 4-23 

4.3.3.1 Decrease street pavement width and length..................................... 4-23 

4.3.3.2 Decrease street right-of-way width.................................................. 4-23 

4.3.3.3 Use alternative cul-de-sac designs ................................................... 4-24 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas

4.3.4 Parking Lot Impervious Surfaces.................................................................... 4-25 

4.3.5 Xeriscaping Techniques.................................................................................. 4-27 

4.4 Information Resources................................................................................................ 4-30 

4.5 References................................................................................................................... 4-32

5 Management Measure 5: New Development Runoff Treatment........................................... 5-1 

5.1 Management Measure................................................................................................... 5-1 

5.2 Management Measure Description and Selection......................................................... 5-2 

5.2.1 Description........................................................................................................ 5-2 

5.2.1.1 Pollutants and total suspended solids................................................. 5-3 

5.2.1.2 Runoff ................................................................................................ 5-5 

5.2.2 Management Measure Selection....................................................................... 5-6 

5.2.3 General Categories of Urban Runoff Control................................................... 5-9 

5.2.3.1 Infiltration practices........................................................................... 5-9 

5.2.3.2 Filtration practices ........................................................................... 5-12 

5.2.3.3 Detention/retention practices ........................................................... 5-12 

5.2.3.4 Evaporation practices....................................................................... 5-13 

5.3 Management Practices ................................................................................................ 5-13 

5.3.1 Infiltration Practices........................................................................................ 5-13 

5.3.1.1 Infiltration basins ............................................................................. 5-13 

5.3.1.2 Infiltration trenches.......................................................................... 5-15 

5.3.1.3 Pervious or porous pavements ......................................................... 5-15 

5.3.2 Vegetated Open Channel Practices................................................................. 5-19 

5.3.3 Filtering Practices ........................................................................................... 5-22 

5.3.3.1 Filtration basins and sand filters ...................................................... 5-22 

5.3.3.2 Media filtration units........................................................................ 5-28 

5.3.3.3 Bioretention systems........................................................................ 5-29 

5.3.4 Detention and Retention Practices.................................................................. 5-34 

5.3.4.1 Detention ponds and vaults.............................................................. 5-34 

5.3.4.2 Retention ponds ............................................................................... 5-34 

5.3.4.3 Constructed wetlands....................................................................... 5-38 

5.3.5 Other Practices................................................................................................ 5-44 

5.3.5.1 Water quality inlets.......................................................................... 5-45 

5.3.5.2 Hydrodynamic devices..................................................................... 5-45 

5.3.5.3 Baffle boxes ..................................................................................... 5-46 

5.3.5.4 Catch basin inserts ........................................................................... 5-46 

5.3.5.5 Alum ................................................................................................ 5-47 

5.3.5.6 Vegetated filter strips....................................................................... 5-47 

5.3.5.7 Street surface and subsurface storage .............................................. 5-49 

5.3.5.8 On-lot storage practices ................................................................... 5-49 

5.3.5.9 Microbial disinfection...................................................................... 5-53 

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5.4 Performance and Cost Information for Management Practices.................................. 5-54 

5.5 Managing Structural Controls to Reduce Mosquito-Breeding Habitat....................... 5-62 

5.6 Information Resources................................................................................................ 5-67 

5.7 References................................................................................................................... 5-71 

6 Management Measure 6: New and Existing On-Site Wastewater Treatment Systems ......... 6-1 

6.1 Management Measure................................................................................................... 6-1 

6.2 Management Measure Description and Selection......................................................... 6-2 

6.2.1 Description........................................................................................................ 6-2 

6.2.2 Management Measure Selection....................................................................... 6-6 

6.3 Management Practices .................................................................................................. 6-6 

6.3.1 Permitting and Installation Programs................................................................ 6-6 

6.3.1.1 Planning activities.............................................................................. 6-7 

6.3.1.1.1 Comprehensive planning ................................................. 6-7 

6.3.1.1.2 Wastewater treatment continuum concept....................... 6-8 

6.3.1.1.3 Centralized sewage treatment .......................................... 6-9 

6.3.1.2 System selection, site evaluation, design, and installation .............. 6-10 

6.3.1.2.1 Performance-based programs......................................... 6-10 

6.3.1.2.2 Modeling system performance and impacts .................. 6-12 

6.3.1.2.3 Applying system siting criteria ...................................... 6-13 

6.3.1.2.4 Site evaluations that assess suitability for specific 

technologies ................................................................... 6-14 

6.3.1.3 Education, training, licensing, and/or certification programs.......... 6-18 

6.3.1.4 Inspection of new on-site wastewater treatment systems ................ 6-21 

6.3.1.5 Installation of conventional or alternative systems.......................... 6-22 

6.3.1.5.1 Pollutant removal processes for conventional systems.. 6-24 

6.3.1.5.2 Septic tanks .................................................................... 6-26 

6.3.1.5.3 Subsurface wastewater infiltration systems................... 6-27 

6.3.1.5.4 Leaching chambers ........................................................ 6-28 

6.3.1.5.5 Alternative systems........................................................ 6-29 

6.3.1.5.6 Elevated systems............................................................ 6-31 

6.3.1.5.7 Intermittent sand/media filters ....................................... 6-32 

6.3.1.5.8 Recirculating sand/media filters .................................... 6-33 

6.3.1.5.9 Anaerobic upflow filters ................................................ 6-33 

6.3.1.5.10 Cluster systems .............................................................. 6-34 

6.3.1.5.11 Constructed wetlands..................................................... 6-34 

6.3.1.5.12 Sequencing batch reactors.............................................. 6-35 

6.3.1.5.13 Aerobic treatment units.................................................. 6-36 

6.3.1.5.14 Fixed film systems ......................................................... 6-36 

6.3.1.5.15 Pressure distribution systems......................................... 6-37 

6.3.1.5.16 Evapotranspiration ......................................................... 6-37 

6.3.1.5.17 Spray irrigation .............................................................. 6-37 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas

6.3.1.5.18 Disinfection devices....................................................... 6-38 

6.3.1.5.19 Water separation systems............................................... 6-38 

6.3.1.5.20 Vaults or holding tanks .................................................. 6-38 

6.3.2 Operation and Maintenance Programs............................................................ 6-38 

6.3.2.1 Development of system inventories and assessment of 

maintenance needs ........................................................................... 6-40 

6.3.2.2 Management, operation, and maintenance policies ......................... 6-42 

6.3.2.2.1 Voluntary Management ................................................. 6-45 

6.3.2.2.2 Regulatory Management................................................ 6-45 

6.3.2.2.3 Direct management ........................................................ 6-46 

6.3.2.3 Inspection and monitoring programs ............................................... 6-47 

6.3.2.3.1 System inspections......................................................... 6-48 

6.3.2.3.2 Improving system effectiveness through water 

conservation and pollutant reduction............................. 6-50 

6.3.2.4 Management of residuals to ensure that they do not present 

significant risks to human health or water resources....................... 6-51 

6.4 Information Resources................................................................................................ 6-54 

6.5 References................................................................................................................... 6-55 

7 Management Measure 7: Bridges and Highways .................................................................. 7-1 

7.1 Management Measure................................................................................................... 7-1 

7.2 Management Measure Description and Selection......................................................... 7-1 

7.2.1 Description........................................................................................................ 7-1 

7.2.2 Management Measure Selection....................................................................... 7-6 

7.3 Management Practices .................................................................................................. 7-7 

7.3.1 Site Planning and Design Practices................................................................... 7-7 

7.3.2 Soil Bioengineering and Other Runoff Controls for Highways........................ 7-8 

7.3.2.1 Live stakes ......................................................................................... 7-8 

7.3.2.2 Fascines.............................................................................................. 7-8 

7.3.2.3 Brushlayers ........................................................................................ 7-8 

7.3.2.4 Branchpacking ................................................................................... 7-8 

7.3.2.5 Live gully repair................................................................................. 7-9 

7.3.2.6 Live cribwalls..................................................................................... 7-9 

7.3.2.7 Vegetated rock gabions...................................................................... 7-9 

7.3.2.8 Vegetated rock walls.......................................................................... 7-9 

7.3.2.9 Joint planting...................................................................................... 7-9 

7.3.2.10 Other runoff and sediment controls for highways ............................. 7-9 

7.3.3 Structural Runoff Controls for Bridges........................................................... 7-10 

7.3.3.1 Scupper drains with runoff conveyance systems............................. 7-10 

7.3.3.2 Other runoff treatment practices ...................................................... 7-11 

7.3.4 Bridge Operation and Maintenance Controls ................................................. 7-11 

7.3.4.1 Enclosures........................................................................................ 7-12 

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7.3.4.2 Containment and collection ............................................................. 7-13 

7.3.5 Nonstructural Runoff Control Practices.......................................................... 7-13 

7.3.5.1 Implement street sweeping .............................................................. 7-13 

7.3.5.2 Consider alternatives to curbs.......................................................... 7-15 

7.3.5.3 Install catch basin inserts ................................................................. 7-15 

7.3.5.4 Control litter and debris on roadsides .............................................. 7-15 

7.3.5.5 Manage pesticide and herbicide use ................................................ 7-16 

7.3.5.6 Reduce fertilizer use ........................................................................ 7-16 

7.3.5.7 Reduce direct discharges.................................................................. 7-16 

7.3.5.8 Practice dewatering.......................................................................... 7-16 

7.3.5.9 Practice spill prevention and control................................................ 7-16 

7.3.5.10 Properly handle and dispose of concrete and cement ...................... 7-16 

7.3.5.11 Manage contaminated soil and water............................................... 7-17 

7.3.5.12 Practice environmentally friendly winter road maintenance ........... 7-17 

7.4 Information Resources................................................................................................ 7-20 

7.5 References................................................................................................................... 7-23 

8 Management Measure 8: Construction Site Erosion, Sediment, and Chemical Control...... 8-1 

8.1 Management Measure................................................................................................... 8-1 

8.2 Management Measure Description and Selection......................................................... 8-1 

8.2.1 Description........................................................................................................ 8-1 

8.2.1.1 Sediment ............................................................................................ 8-2 

8.2.1.2 Pesticides............................................................................................ 8-3 

8.2.1.3 Petroleum products ............................................................................ 8-4 

8.2.1.4 Fertilizers ........................................................................................... 8-4 

8.2.1.5 Solid wastes ....................................................................................... 8-4 

8.2.1.6 Construction chemicals...................................................................... 8-4 

8.2.1.7 Contaminated soils............................................................................. 8-5 

8.2.2 Management Measure Selection....................................................................... 8-5 

8.3 Management Practices .................................................................................................. 8-6 

8.3.1 Erosion and Sediment Control Programs.......................................................... 8-6 

8.3.1.1 Prepare erosion and sediment control plans....................................... 8-6 

8.3.1.2 Provide education and training opportunities for construction 

personnel............................................................................................ 8-9 

8.3.1.3 Establish plan review and modification procedures ........................ 8-10 

8.3.1.4 Assess ESC practices after storm events ......................................... 8-10 

8.3.1.5 Ensure ESC plan implementation .................................................... 8-11 

8.3.2 Erosion Control Practices ............................................................................... 8-12 

8.3.2.1 Schedule projects so clearing and grading are done during the 

time of minimum erosion potential.................................................. 8-12 

8.3.2.2 Phase construction ........................................................................... 8-12 

8.3.2.3 Practice site fingerprinting............................................................... 8-14 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas

8.3.2.4 Locate potential pollutant sources away from steep slopes, water 

bodies, and critical areas.................................................................. 8-14 

8.3.2.5 Route construction traffic to avoid existing or newly planted 

vegetation......................................................................................... 8-14 

8.3.2.6 Protect natural vegetation with fencing, tree armoring, and 

retaining walls or tree wells ............................................................. 8-14 

8.3.2.7 Protect environmentally sensitive areas........................................... 8-14 

8.3.2.8 Stockpile topsoil and reapply as a soil amendment to 

reestablish vegetation....................................................................... 8-15 

8.3.2.9 Cover or stabilize soil stockpiles ..................................................... 8-16 

8.3.2.10 Use wind erosion controls................................................................ 8-16 

8.3.2.11 Intercept runoff above disturbed slopes and convey it to a 

permanent channel or storm drain.................................................... 8-16 

8.3.2.12 On long or steep, disturbed, or man-made slopes, construct 

benches, terraces, or ditches at regular intervals to intercept 

runoff................................................................................................ 8-16 

8.3.2.13 Use retaining walls........................................................................... 8-16 

8.3.2.14 Provide linings for urban runoff conveyance channels.................... 8-16 

8.3.2.15 Use check dams................................................................................ 8-17 

8.3.2.16 Seed disturbed areas......................................................................... 8-17 

8.3.2.17 Use mulches..................................................................................... 8-18 

8.3.2.18 Use sodding for permanent stabilization.......................................... 8-18 

8.3.2.19 Install erosion control blankets ........................................................ 8-19 

8.3.2.20 Use chemicals such as PAM to stabilize soils ................................. 8-20 

8.3.2.21 Use wildflower cover....................................................................... 8-22 

8.3.3 Sediment Control Practices............................................................................. 8-22 

8.3.3.1 Install sediment basins ..................................................................... 8-22 

8.3.3.2 Use modified risers and skimmers................................................... 8-24 

8.3.3.3 Install sediment traps ....................................................................... 8-25 

8.3.3.4 Use silt fence.................................................................................... 8-25 

8.3.3.5 Install compost filter berms ............................................................. 8-27 

8.3.3.6 Establish inlet protection.................................................................. 8-27 

8.3.3.7 Designate and reinforce construction entrances .............................. 8-27 

8.3.3.8 Install vegetated filter strips............................................................. 8-28 

8.3.3.9 Use vegetated buffers....................................................................... 8-28 

8.3.4 Develop and Implement Programs to Control Chemicals and Other 

Construction Materials.................................................................................... 8-28 

8.3.4.1 Develop and implement a materials management program............. 8-28 

8.3.4.2 Develop and implement a spill control plan .................................... 8-30 

8.3.4.3 Develop and implement a waste disposal program.......................... 8-31 

8.4 Information Resources................................................................................................ 8-34 

8.5 References................................................................................................................... 8-37 

9 Management Measure 9: Pollution Prevention...................................................................... 9-1 

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9.1 Management Measure................................................................................................... 9-1 

9.2 Management Measure Description and Selection......................................................... 9-1 

9.2.1 Description........................................................................................................ 9-1 

9.2.1.1 Household chemicals ......................................................................... 9-2 

9.2.1.2 Failing septic systems ........................................................................ 9-3 

9.2.1.3 Lawn and garden activities ................................................................ 9-3 

9.2.1.4 Commercial activities ........................................................................ 9-4 

9.2.1.5 Pet wastes........................................................................................... 9-5 

9.2.1.6 Trash .................................................................................................. 9-5 

9.2.2 Management Measure Selection....................................................................... 9-6 

9.3 Management Practices .................................................................................................. 9-6 

9.3.1 Household Chemicals ....................................................................................... 9-6 

9.3.1.1 Educate the public on proper storage and disposal of household 

chemicals............................................................................................ 9-7 

9.3.1.2 Conduct storm drain marking ............................................................ 9-7 

9.3.1.3 Encourage responsible car washing practices.................................... 9-7 

9.3.2 Lawn, Garden, and Landscape Activities ......................................................... 9-8 

9.3.2.1 Lawn conversion................................................................................ 9-9 

9.3.2.2 Soil building..................................................................................... 9-10 

9.3.2.3 Grass selection ................................................................................. 9-10 

9.3.2.4 Mowing and thatch management..................................................... 9-11 

9.3.2.5 Yard waste management.................................................................. 9-11 

9.3.2.6 Minimal fertilization ........................................................................ 9-12 

9.3.2.7 Weed control and tolerance ............................................................. 9-13 

9.3.2.8 Pest management ............................................................................. 9-13 

9.3.2.9 Point-of-sale education .................................................................... 9-16 

9.3.2.10 Sensible irrigation ............................................................................ 9-17 

9.3.3 Commercial Activities .................................................................................... 9-18 

9.3.3.1 Detect and eliminate illicit connections........................................... 9-18 

9.3.3.2 Encourage good housekeeping practices at commercial facilities... 9-21 

9.3.3.3 Provide training and education for employees and customers......... 9-21 

9.3.3.4 Devise spill prevention, control, and clean-up plans ....................... 9-22 

9.3.3.5 Conduct an environmental audit ...................................................... 9-22 

9.3.3.6 Practice safe equipment washing and maintenance......................... 9-22 

9.3.3.7 Use care when performing construction, repairs, or remodeling..... 9-23 

9.3.3.8 Proper disposal of pet waste ............................................................ 9-23 

9.3.4 Trash ............................................................................................................... 9-24 

9.3.5 Nonpoint Source Pollution Education for Citizens......................................... 9-25 

9.3.5.1 Use multilingual nonpoint source messages.................................... 9-26 

9.3.5.2 Use classroom education to deliver nonpoint source messages....... 9-26 

9.4 Information Resources................................................................................................ 9-28 

9.4.1 General............................................................................................................ 9-28 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas

9.4.2 Yards: General Resources............................................................................... 9-32 

9.4.3 Yard Resources for Homeowners ................................................................... 9-32 

9.4.4 Yard Resources for Lawn Care Professionals ................................................ 9-32 

9.5 References................................................................................................................... 9-34 

10 Management Measure 10: Existing Development............................................................... 10-1 

10.1 Management Measure................................................................................................. 10-1 

10.2 Management Measure Description and Selection....................................................... 10-1 

10.2.1 Description...................................................................................................... 10-1 

10.2.2 Management Measure Selection..................................................................... 10-3 

10.3 Management Practices ................................................................................................ 10-4 

10.3.1 Identify, Prioritize, and Schedule Retrofit Opportunities ............................... 10-4 

10.3.1.1 Evaluate existing data ...................................................................... 10-4 

10.3.1.2 Choose appropriate management practices based on site 

conditions......................................................................................... 10-5 

10.3.1.3 Incorporate low-impact development practices into existing 

development..................................................................................... 10-5 

10.3.1.4 Identify undeveloped and privately owned land for acquisition...... 10-6 

10.3.1.5 Use routine maintenance as an opportunity for retrofitting 

existing infrastructure ...................................................................... 10-6 

10.3.2 Implement Retrofit Projects as Scheduled...................................................... 10-7 

10.3.2.1 Retrofit existing runoff management facilities ................................ 10-7 

10.3.2.2 Modify the upstream end of road culverts ....................................... 10-8 

10.3.2.3 Modify storm drainage pipe outfalls................................................ 10-9 

10.3.2.4 Add retention structures to channelized streams ............................. 10-9 

10.3.2.5 Install runoff management practices in or adjacent to large 

parking areas .................................................................................. 10-10 

10.3.2.6 Construct new practices in highway rights-of-way ....................... 10-10 

10.3.2.7 Install trash-capturing devices ....................................................... 10-10 

10.3.2.8 Install inlet and grate inserts .......................................................... 10-10 

10.3.3 Restore and Limit the Destruction of Natural Runoff Conveyance 

Systems ......................................................................................................... 10-10

10.3.3.1 Disconnect impervious areas ......................................................... 10-11 

10.3.3.2 Encourage overland sheet flow...................................................... 10-12 

10.3.3.3 Increase flow path.......................................................................... 10-12 

10.3.3.4 Use open swales in place of traditional storm drain systems......... 10-12 

10.3.3.5 Establish vegetation throughout the site ........................................ 10-12

10.3.3.6 Reestablish ground water recharge ................................................ 10-13 

10.3.3.7 Protect sensitive areas.................................................................... 10-14 

10.3.4 Restore Natural Streams ............................................................................... 10-14 

10.3.4.1 Partially restore the predevelopment hydrologic regime ............... 10-15 

10.3.4.2 Stabilize channel morphology........................................................ 10-15 

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Table of Contents

10.3.4.3 Restore instream habitat structure.................................................. 10-16 

10.3.4.4 Reestablish riparian cover.............................................................. 10-16 

10.3.4.5 Protect critical stream substrates.................................................... 10-18 

10.3.4.6 Promote recolonization of the aquatic community ........................ 10-18 

10.3.4.7 Daylight streams ............................................................................ 10-18 

10.3.5 Preserve, Enhance, or Establish Buffers....................................................... 10-19 

10.3.6 Redevelop Urban Areas to Decrease Runoff-Related Impacts..................... 10-20 

10.3.6.1 Encourage infill development........................................................ 10-20 

10.3.6.2 Assess vacant, abandoned lots and areas of potentially 

contaminated soils to promote redevelopment .............................. 10-20 

10.4 Information Resources.............................................................................................. 10-22 

10.5 References................................................................................................................. 10-24 

11 Management Measure 11: Operation and Maintenance ...................................................... 11-1 

11.1 Management Measure................................................................................................. 11-1 

11.2 Management Measure Description and Selection....................................................... 11-1 

11.2.1 Description...................................................................................................... 11-1 

11.2.2 Management Measure Selection..................................................................... 11-2 

11.3 Management Practices ................................................................................................ 11-3 

11.3.1 Establishing an Operation and Maintenance Program.................................... 11-3 

11.3.2 Source Control Operation and Maintenance................................................... 11-7 

11.3.3 Treatment Control Operation and Maintenance ............................................. 11-9 

11.4 Information Resources.............................................................................................. 11-17 

11.5 References................................................................................................................. 11-18 

12 Management Measure 12: Evaluate Program Effectiveness ............................................... 12-1 

12.1 Management Measure................................................................................................. 12-1 

12.2 Management Measure Description and Selection....................................................... 12-1 

12.2.1 Description...................................................................................................... 12-1 

12.2.2 Management Measure Selection..................................................................... 12-1 

12.3 Management Practices ................................................................................................ 12-1 

12.3.1 Assess the Runoff Management Program Framework ................................... 12-1 

12.3.1.1 Qualitative measures........................................................................ 12-2 

12.3.1.2 Quantitative measures...................................................................... 12-3 

12.3.1.3 Quality assurance/quality control .................................................... 12-3 

12.3.2 Track Management Practice Implementation ................................................. 12-4 

12.3.2.1 Track permits ................................................................................... 12-4 

12.3.2.2 Use operation and maintenance records .......................................... 12-4 

12.3.2.3 Use geographic information systems............................................... 12-5 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas

12.3.2.4 Develop surveys............................................................................... 12-5 

12.3.2.5 Consider expert evaluations............................................................. 12-6 

12.3.3 Gauge Improvements in Water Quality Resulting from Management 

Practice Implementation ................................................................................. 12-6 

12.3.3.1 Conduct trend monitoring................................................................ 12-9 

12.3.3.2 Conduct effectiveness monitoring ................................................... 12-9 

12.3.4 Develop and Implement a Schedule to Improve the Management Program 

Framework.................................................................................................... 12-10 

12.4 Information Resources.............................................................................................. 12-11 

12.5 References................................................................................................................. 12-12 

List of Figures 

Figure 0.1: Components of a comprehensive runoff management program ............................. 0-2 

Figure 0.2: Twelve management measures associated with the runoff management 

program cycle.......................................................................................................... 0-4 

Figure 0.3: Scales of watershed management units................................................................. 0-16 

Figure 0.4: Impacts of urbanization on the water cycle .......................................................... 0-22 

Figure 0.5: Changes in stream flow hydrograph as a result of urbanization........................... 0-23 

Figure 0.6: Response of stream geometry to urbanization...................................................... 0-23 

Figure 0.7: Relationship between impervious cover and aquatic insect diversity in 

Anacostia River subwatersheds ............................................................................ 0-27 

Figure 0.8: Fish diversity in four subwatersheds of different impervious cover in the 

Maryland Piedmont............................................................................................... 0-28 

Figure 1.1: Adopted watershed protection plan for the City of High Point, North Carolina .... 1-7 

Figure 1.2: Example of part of a subwatershed base map....................................................... 1-17 

Figure 2.1: Conceptual process for assessing cumulative effects ........................................... 2-11 

Figure 2.2: Conceptual diagram of the stressor identification process ................................... 2-20 

Figure 4.1: Schematic of a residential cluster development...................................................... 4-7 

Figure 4.2: Schematic of a rural cluster development............................................................... 4-7 

Figure 4.3: Development of a conservation subdivision......................................................... 4-12 

Figure 4.4: Schematic drawings of conventional (a), parkway (b), and clustered (c) 

development scenarios for the Chapel Run subdivision....................................... 4-13 

Figure 4.5: Schematic representation of directly connected and not-directly connected 

impervious areas. .................................................................................................. 4-16 

Figure 4.6: Components of the vegetated roof cover. ............................................................. 4-18 

Figure 4.7: Runoff attenuation efficiency for a 0.4-inch rainfall event with saturated 

Media .................................................................................................................... 4-19 

Figure 4.8: Five turnaround options at the end of a residential street. .................................... 4-25 

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Table of Contents

Figure 4.9: Impervious cover created by each turnaround option shown in Figure 4.8.......... 4-26 

Figure 5.1: Schematic of an infiltration basin ......................................................................... 5-14 

Figure 5.2: Schematic of an infiltration trench........................................................................ 5-16 

Figure 5.3: Photo showing several types of pervious modular pavement installations........... 5-17 

Figure 5.4: Schematic of a grass channel. ............................................................................... 5-20 

Figure 5.5: Schematic of a dry swale. .................................................................................... 5-21 

Figure 5.6: Schematic of a surface sand filter. ........................................................................ 5-24 

Figure 5.7: Schematic of an underground sand filter. ............................................................. 5-25 

Figure 5.8: Schematic of a perimeter sand filter. .................................................................... 5-26 

Figure 5.9: Schematic of an organic media filter. ................................................................... 5-27 

Figure 5.10: Schematic of a multi-chambered treatment train .................................................. 5-28 

Figure 5.11: Schematic of a bioretention system. ..................................................................... 5-30 

Figure 5.12: Schematic of a bioretention parking lot island. .................................................... 5-31 

Figure 5.13: Schematic of a dry extended detention pond ........................................................ 5-35 

Figure 5.14: Schematic of a wet pond....................................................................................... 5-36

Figure 5.15: Schematic of a shallow wetland............................................................................ 5-39 

Figure 5.16: Schematic of a vegetated filter strip...................................................................... 5-48 

Figure 5.17: Runoff pooling on a street surface designed for temporary storage. .................... 5-49 

Figure 5.18: A rain barrel that collects runoff from a roof gutter downspout........................... 5-50 

Figure 6.1: Conventional on-site wastewater treatment system................................................ 6-4 

Figure 6.2: Septic tank detail................................................................................................... 6-22 

Figure 6.3: Leaching chamber subsurface wastewater infiltration system.............................. 6-29 

Figure 6.4: Schematic of a typical mound system................................................................... 6-32 

Figure 6.5: Components of a vegetated submerged bed.......................................................... 6-35 

Figure 7.1: Median hydrocarbon concentrations by land use.................................................... 7-2 

Figure 8.1: Schematic of the basic polymer treatment system................................................ 8-21 

List of Tables 

Table 0.1: Leading sources of water quality impairment related to human activities 

for rivers, lakes, and estuaries................................................................................. 0-1 

Table 0.2: Key differences between the Guidance Specifying Management Measures for 

Sources of Nonpoint Pollution in Coastal Waters and National Management 

Measures to Control Nonpoint Source Pollution from Urban Areas. .................... 0-7 

Table 0.3: Comparison of management measures to the six minimum control 

measures of NPDES Phase II.................................................................................. 0-9 

Table 0.4: National stream order statistics............................................................................. 0-14 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas

Table 0.5: Idealized characteristics of five watershed management units with respect 

to size and the influence of impervious cover ...................................................... 0-20 

Table 0.6: Characteristics of aquatic integrity in urban watersheds. ..................................... 0-21 

Table 0.7: Impacts from increases in impervious surfaces .................................................... 0-24 

Table 0.8: Summary of case studies linking urbanization to hydrological impacts 

on streams ............................................................................................................. 0-24 

Table 0.9: Typical pollutant concentrations found in urban storm water .............................. 0-29 

Table 1.1: Summary of the Randleman Lake water supply watershed protection rules.......... 1-6 

Table 1.2: Redesign analyses comparing impervious cover and storm water runoff 

from conventional and open space subdivisions..................................................... 1-9 

Table 1.3: Elements of three watershed management structures ........................................... 1-22 

Table 1.4: Types of taxes and fees that can be used to raise money for storm water 

management programs.......................................................................................... 1-29 

Table 3.1: Cost comparison of stream preservation vs. stream restoration ............................. 3-3 

Table 3.2: Types of lands that should be preserved for watershed protection......................... 3-5 

Table 4.1: Theoretical comparison of conventional and low-impact alternative designs 

for the Chapel Run site. ........................................................................................ 4-14 

Table 4.2: Theoretical comparison of itemized costs for conventional and low-impact 

alternative designs for the Chapel Run site........................................................... 4-15 

Table 5.1: Sediment particle size distribution.......................................................................... 5-4 

Table 5.2: Select local and state programs with TSS performance standards ......................... 5-6 

Table 5.3: Select local programs with peak discharge and/or runoff volume performance 

standards ................................................................................................................. 5-7 

Table 5.4: Pollutant removal efficiencies for the compost storm water treatment facility 

from 1991 to 1994................................................................................................. 5-29 

Table 5.5: Design considerations for ponds and wetlands..................................................... 5-37 

Table 5.6: Advantages and disadvantages of management practices .................................... 5-54 

Table 5.7: Regional, site-specific, and maintenance considerations for management 

practices. ............................................................................................................... 5-57 

Table 5.8: Effectiveness of management practices for runoff control................................... 5-59 

Table 5.9: Costs of selected management practices............................................................... 5-61 

Table 6.1: Common causes of OWTS failure .......................................................................... 6-2 

Table 6.2: Pollutants of concern for OWTSs........................................................................... 6-3 

Table 6.3: Site features that should be evaluated before OWTS design and installation. ..... 6-16 

Table 6.4: Practices to characterize surface and subsurface features of proposed 

OWTS sites ........................................................................................................... 6-16 

Table 6.5: Practices to characterize subsurface conditions through test pit inspection. ........ 6-17 

Table 6.6: Survey of state certification and licensing programs for onsite wastewater 

service providers ................................................................................................... 6-19 

Table 6.7: Treatment technologies for OWTSs. .................................................................... 6-23 

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Table of Contents

Table 6.8: Wastewater constituents of concern and representative estimates of 

concentrations in the effluent of various treatment units...................................... 6-26 

Table 6.9: Summary of estimated capital and operation and maintenance costs 

for OWTSs............................................................................................................ 6-30 

Table 6.10: Guidelines for OWTS management programs under a tiered approach. .............. 6-43 

Table 6.11: Program elements and functional responsibilities example matrix. .................... 6-44 

Table 6.12: Comparison of current and federally mandated flow rates and flush 

volumes................................................................................................................. 6-51 

Table 6.13: Residential wastewater pollutant contributions by source.................................... 6-51 

Table 7.1: Primary sources of highway runoff pollutants........................................................ 7-4 

Table 7.2: Range of average values for runoff contaminant concentration for 

selected highway contaminants............................................................................... 7-4 

Table 7.3: Results of three studies that analyzed chemical and physical parameters of 

snowmelt................................................................................................................. 7-6 

Table 7.4: Street dirt chemical quality ................................................................................... 7-14 

Table 7.5: Advantages and disadvantages of road salt and alternative deicing chemicals .... 7-18 

Table 8.1: Erosion and sediment associated with construction................................................ 8-3 

Table 8.2: ESC plan requirement for selected states................................................................ 8-7 

Table 8.3: Cost and effectiveness of selected erosion control practices ................................ 8-13 

Table 8.4: Summary of operating performance data for six test sites.................................... 8-21 

Table 8.5: Cost and effectiveness for selected sediment control practices ............................ 8-23 

Table 8.6: Sediment retention efficiency of sediment basins ................................................ 8-25 

Table 9.1: Mowing heights for various grass types ............................................................... 9-11 

Table 9.2: Select cost and audience information for various outreach techniques ................ 9-25 

Table 11.1: Properties of urban storm water solids/residuals .................................................. 11-6 

Table 11.2: Street sweeper O&M costs.................................................................................... 11-8 

Table 11.3: Maintenance costs, activities, and schedules for runoff control practices 

in 1998 dollars....................................................................................................... 11-9 

Table 11.4: Typical O&M equipment and material costs...................................................... 11-15 

Table 12.1: Examples of variables that can be measured to assess changes in 

management practice implementation and water quality...................................... 12-8 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas

 xviii 
Introduction 

INTRODUCTION 

The nation's aquatic resources are among its most valuable assets. Although environmental 

protection programs in the United States have improved water quality during the past several 

decades, many challenges remain. Of special concern are the problems in our urban streams, 

lakes, estuaries, aquifers, and other water bodies caused by runoff that is inadequately controlled 

or treated. These problems include changes in flow, increased sedimentation, higher water 

temperature, lower dissolved oxygen, degradation of aquatic habitat structure, loss of fish and 

other aquatic populations, and decreased water quality due to increased levels of nutrients, 

metals, hydrocarbons, bacteria, and other constituents. 

The National Water Quality Inventory: 2000 Report to Congress identified urban runoff as one 

of the leading sources of water quality impairment in surface waters (USEPA, 2002b). Of the 11 

pollution source categories listed in the report, “urban runoff/storm sewers” was ranked as the 

fourth leading source of impairment in rivers, third in lakes, and second in estuaries (Table 0.1). 

Table 0.1: Leading sourcesb of water quality impairment related to human activities for 

rivers, lakes, and estuaries (USEPA, 2002b). 

Rivers and Streams Lakes, Ponds, and Reservoirs Estuaries 

Agriculture (48%) a Agriculture (41%) a Municipal point sources (37%)a

Hydrologic modifications (20%) Hydrologic modifications (18%) Urban runoff/storm sewers (32%)

Habitat modifications (14%) Urban runoff/storm sewers (18%) Industrial discharges (26%) 

Urban runoff/storm sewers (13%) Misc. nonpoint source pollution (14%) Atmospheric deposition (24%) 

a

Values in parentheses represent the percentage of assessed river miles, lake acres, or estuary square miles that are classified as 

impaired. States assessed 19% of stream miles, 43% of lakes, ponds, and reservoirs, and 36% of square mileage of estuaries. 

b Excluding unknown, natural, and “other” sources. 

0.1 Purpose and Scope of the Guidance 

National summaries, such as those shown in Table 0.1, are useful in providing an overview of 

the magnitude of the problems associated with urban runoff. Solutions, however, are usually 

applied at the local level. State and local elected officials and agencies, landowners, developers, 

environmental and conservation groups, and others play a crucial role in protecting, maintaining, 

and restoring water resources. Their efforts, in aggregate, form the basis for changing the status 

of urban runoff from a local problem to a national problem. 

This document provides guidance to states, territories, authorized tribes, and the public regarding 

management measures that can be used to reduce nonpoint source pollution from urban 

activities. This document refers to statutory and regulatory provisions that contain legally 

binding requirements. This document does not substitute for those provisions or regulations, nor 

is it a regulation itself. Thus, it does not impose legally binding requirements on the U.S. 

Environmental Protection Agency (EPA), states, territories, authorized tribes, or the public and 

may not apply to a particular situation based upon the circumstances. EPA, state, territory, and 

 0-1 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

authorized tribe decision-makers retain the discretion to adopt approaches that differ from this 

guidance on a case-by-case basis. Interested parties are free to raise questions and objections 

about the appropriateness of the application of the guidance to a situation, and EPA will consider 

whether or not the recommendations in this guidance are appropriate in that situation. EPA may 

change this guidance in the future. 

This guidance document is intended to provide technical assistance to state and local program 

managers and other practitioners on the best available, most economically achievable means of 

managing urban runoff and reducing nonpoint source pollution of surface and ground waters 

from urban sources. It describes how to develop a comprehensive runoff management program 

that deals with all phases of development—from predevelopment watershed planning and site 

design, through the construction phase of development, to the operation and maintenance of 

structural controls. It also provides information for other situations such as retrofitting existing 

development, implementing nonstructural controls, and reevaluating the runoff management 

program. Figure 0.1 presents the components of a comprehensive runoff management program. 

Establish program

framework

Establish program

framework

Evaluate program

effectiveness

Evaluate program

effectiveness

Conduct operation and

maintenance

Conduct operation and

maintenance

Retrofit existing

development

Retrofit existing

development

Assess existing

conditions

Assess existing

conditions

Plan and design new

development

Plan and design new

development

Perform construction Perform construction

Implement pollution

prevention

Implement pollution

prevention

Runoff

Management

Program

Figure 0.1: Components of a comprehensive runoff management program. 

This document is intended to provide guidance for all urban areas, not just those covered by 

National Pollutant Discharge Elimination System (NPDES) phase II requirements. While the 

document can serve as a resource for meeting NPDES phase II requirements, there are still a 

number of smaller jurisdictions that are not regulated by the NPDES program and that can 

benefit from guidance in developing an urban runoff program. 

0-2 
Introduction 

0.1.1 Management Measures 

Management measures can be used to guide the development of a runoff management program. 

They establish performance expectations and, in many cases, specify actions that can be taken to 

prevent or minimize nonpoint source pollution or other negative impacts associated with 

uncontrolled and untreated urban runoff. Twelve management measures have been included in 

this guidance. Figure 0.2 groups these measures within the context of the runoff management 

program cycle. 

Each management measure listed in Figure 0.2 deals with an important aspect of the runoff 

management cycle. For example, Management Measure 8 focuses on construction site erosion, 

sediment, and chemical control. Local officials and developers should address these issues 

because if exposed soils are allowed to erode and move off construction sites as sediment, they 

can clog storm drains, streams, and other water bodies, harm habitat, and impair water quality. 

This management measure has four elements: 

— Prior to land disturbance, prepare and implement an approved erosion and sediment 

control plan or similar administrative document that contains erosion and sediment 

control provisions. 

— Reduce erosion and, to the extent practicable, retain sediment on-site during and after 

construction. 

— Use good housekeeping practices to prevent off-site transport of waste material and 

chemicals. 

— Minimize application and generation of potential pollutants, including chemicals. 

Note that specific actions or practices for achieving the performance expectations are not 

included in the management measure statement. This is by design. Local officials and other 

practitioners need the flexibility to choose management practices that best achieve the 

management measure's performance expectations given their own unique circumstances. To aid 

in their decision, however, this guidance presents several management practices that can 

potentially be used to achieve each management measure. 

The components of the runoff management program shown in Figure 0.2 are organized in a cycle 

that can be followed stepwise if desired. The elements are meant to work together, but each can 

stand alone. The elements of the cycle do not have to be implemented consecutively. 

The cycle begins with establishing a program framework that provides legal authority, funding, 

and staffing for watershed initiatives (Management Measure 1). Once this framework is 

established, watershed managers can commence an assessment of existing conditions 

(Management Measure 2) to identify areas in need of protection or restoration. This assessment 

also provides stream channel and water quality baselines (i.e., environmental indicators) against 

which the success of watershed initiatives can be compared (Management Measure 12: Evaluate 

Program Effectiveness). 

Management Measures 3 through 7 address issues associated with new development. The 

watershed protection management measure (3) focuses on siting development and establishing 

 0-3 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

12 Evaluation of 

management program 

effectiveness

12 Evaluation of 

management program 

effectiveness

11 Operation and 

maintenance

11 Operation and 

maintenance

10 Retrofitting existing 

development

10 Retrofitting existing 

development

8 Construction site 

erosion, sediment, and 

chemical control

8 Construction site 

erosion, sediment, and 

chemical control

3 Watershed protection

4 Site development

5 New development runoff 

treatment

6 New and existing onsite 

wastewater treatment 

systems

7 Bridges and highways

3 Watershed protection

4 Site development

5 New development runoff 

treatment

6 New and existing onsite 

wastewater treatment 

systems

7 Bridges and highways

2 Watershed assessment 2 Watershed assessment

1 Program framework and 

objectives

1 Program framework and 

objectives

9 Pollution prevention 9 Pollution prevention

Establish program 

framework (Chapter 2)

Evaluate program 

effectiveness (Chapter 9)

Conduct operation and 

maintenance (Chapter 8)

Retrofit existing 

development (Chapter 7)

Assess existing conditions 

(Chapter 3)

Plan and design new 

development (Chapter 4)

Perform construction 

(Chapter 5)

Implement pollution 

prevention (Chapter 6)

12 Evaluation of 

management program 

effectiveness

12 Evaluation of 

management program 

effectiveness

11 Operation and 

maintenance

11 Operation and 

maintenance

10 Retrofitting existing 

development

10 Retrofitting existing 

development

8 Construction site 

erosion, sediment, and 

chemical control

8 Construction site 

erosion, sediment, and 

chemical control

3 Watershed protection

4 Site development

5 New development runoff 

treatment

6 New and existing onsite 

wastewater treatment 

systems

7 Bridges and highways

3 Watershed protection

4 Site development

5 New development runoff 

treatment

6 New and existing onsite 

wastewater treatment 

systems

7 Bridges and highways

2 Watershed assessment 2 Watershed assessment

1 Program framework and 

objectives

1 Program framework and 

objectives

9 Pollution prevention 9 Pollution prevention

Establish program 

framework (Chapter 2)

Evaluate program 

effectiveness (Chapter 9)

Conduct operation and 

maintenance (Chapter 8)

Retrofit existing 

development (Chapter 7)

Assess existing conditions 

(Chapter 3)

Plan and design new 

development (Chapter 4)

Perform construction 

(Chapter 5)

Implement pollution 

prevention (Chapter 6)

Figure 0.2: Twelve management measures associated with the runoff management 

program cycle. 

actions to protect areas identified as sensitive or ecologically valuable. The Site Development 

Management Measure (4) provides guidance for planning development on the site scale with 

alternative, low-impact site layouts and infrastructure options that protect sensitive areas and 

0-4 
Introduction 

reduce the quantity of runoff leaving the site. The New Development Runoff Treatment 

Management Measure (5) details practices that can be identified to prevent pollutants in runoff 

generated from newly developed areas. The onsite wastewater treatment systems management 

measure (6) provides guidance on how to reduce pollutant loadings from both new and existing 

on-site systems. Finally, the Highways and Bridges Management Measure (7) addresses 

pollutants generated from activities related to new and existing transportation infrastructure. 

Once development plans have been made, watershed managers can refer to Management 

Measure 8: Construction Site Erosion, Sediment, and Chemical Control. This measure presents 

practices that reduce pollutant loadings from land-disturbing activities. 

Throughout the runoff management program cycle, watershed managers can use the Pollution 

Prevention Management Measure (9) to target municipalities, businesses, and individual citizens 

with education and awareness programs to reduce pollutants generated from day-to-day 

activities. Managers also can use the practices presented in the Existing Development 

Management Measure (10) to address areas in need of restoration or retrofitting of existing 

management practices. Additionally, the Operation and Maintenance Management Measure (11) 

describes activities needed to maintain and extend the life of new and existing management 

practices. 

Once programs have been established and management practices implemented, managers can 

evaluate their effectiveness using program and administrative indicators (Management Measure 

12). This evaluation involves reassessing conditions in the watershed to determine whether the 

implemented practices effectively reduced nonpoint source pollution. This evaluation also 

identifies areas where additional restoration or preservation activities are needed, guiding future 

watershed initiatives and thereby restarting the management cycle.

This 96-square-mile watershed was affected by storm water runoff from two counties and 24 towns. 

The partners in the North Branch of the Chicago River Demonstration Project divided the project into 

four tasks—developing a watershed plan, conducting an information and education campaign, 

developing a handbook to guide them through the process, and conducting a series of demonstration 

projects. For more information, contact Friends of the Chicago River (http://www.chicagoriver.org). 

Through the North Branch of the Chicago River Demonstration Project, the Friends of the Chicago 

River, and the Lake County Storm Water Management Commission joined to develop a plan to address 

NPS pollution and flooding while educating and involving citizens and community leaders in the 

process (USEPA, 2000a). The result was an urban watershed planning model, similar to the one 

presented in this guidance, that any city can use to protect its water resources. 

North Branch of the Chicago River Demonstration Project

0.1.2 Document Organization 

Chapters 2 through 9 of this document consecutively focus on the eight components of the runoff 

management program cycle (Figure 0.2). Each chapter describes a component, introduces one or 

more management measures that define the performance expectation(s) for that component, and 

presents a range of management practices that potentially can be implemented to achieve the 

management measure(s). When available, information concerning effectiveness and costs of 

 0-5 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

practices is included in the discussion, as are case studies that illustrate how select management 

practices have been implemented within communities. 

0.2 Origin and Regulatory Context 

0.2.1 Origin of This Guidance 

This document is an update of the urban management measures and practices provided in 

Chapter 4 of an EPA manual entitled Guidance Specifying Management Measures for Sources of 

Nonpoint Pollution in Coastal Waters (USEPA, 1993). That document, referred to hereafter as 

the Coastal Management Measures Guidance, was published in January 1993 for the specific 

purpose of providing state and territorial officials with management measures to incorporate into 

their coastal nonpoint source (NPS) pollution control programs. 

Through the Coastal Zone Act Reauthorization Amendments of 1990 (CZARA), Congress 

mandated that EPA develop the Coastal Management Measures Guidance, and that every state 

and territory with an approved coastal zone management program develop an NPS pollution 

control program, including enforceable policies and mechanisms to implement all of the 

specified management measures. The programs were submitted to EPA and the National Oceanic 

and Atmospheric Administration (NOAA) for approval. All were subsequently approved, some 

with conditions. The Coastal Management Measures Guidance functions as a blueprint for the 

coastal states and territories in their efforts to put together their NPS control programs. 

The Coastal Management Measures Guidance included management measures for urban areas 

(Chapter 4), agriculture (Chapter 2), silviculture (Chapter 3), marinas (Chapter 5), and 

hydromodification (Chapter 6). It also addressed protection of wetlands and riparian areas from 

NPS pollution impacts and the use of vegetative treatment systems, such as constructed 

wetlands, as management practices to control runoff (Chapter 7). 

Of all the NPS pollution sources identified in the Coastal Management Measures Guidance, none 

has experienced the rapid technical advancement that has occurred in the areas of urban NPS 

pollution control. Many communities have set their sights beyond simple NPS pollutant 

reduction targets and are now seeking ways to achieve balance and integration of many qualityof-life factors, including economic growth, community livability, and environmental protection. 

Based on these changes, EPA perceived a need to update and expand the information in Chapter 

4 of the Coastal Management Measures Guidance to help local urban officials in both coastal and 

inland areas remain current with state-of-the-art management measures and practices. Readers 

should note, however, that this guidance does not supplement or replace the 1993 Guidance 

Specifying Management Measures for Sources of Nonpoint Pollution in Coastal Waters for the 

purpose of implementing programs under CZARA. It simply serves as an additional resource 

guide for local officials seeking to develop or improve their urban runoff management programs. 

Fundamental differences between this guidance and the Coastal Management Measures 

Guidance are presented in Table 0.2. 

0-6 
Introduction 

Table 0.2: Key differences between the Guidance Specifying Management Measures for 

Sources of Nonpoint Pollution in Coastal Waters (USEPA, 1993) and National Management 

Measures to Control Nonpoint Source Pollution from Urban Areas. 

Guidance Specifying Management 

Measures for Sources of Nonpoint 

Pollution in Coastal Waters

National Management Measures to 

Control Nonpoint Source Pollution from 

Urban Areas

Date 1993 2005 

Target audience Primary: state and territory officials 

Secondary: all others interested in NPS 

pollution 

All persons interested in urban NPS pollution 

and control practices 

Focus NPS management measures and control 

practices in coastal areas 

NPS management measures and control 

practices in coastal and inland areas 

Use Required under CZARA Voluntary 

Organization Management measures and practices 

presented by source category 

Management measures and practices 

presented in the context of a comprehensive 

watershed program

0.2.2 Regulatory Context 

During the first 15 years (1972–1987) of the national program to abate and control water 

pollution, EPA and the states focused most of their activities on traditional point sources. These 

point sources have been regulated by EPA and the states through the NPDES permit program 

established by Section 402 of the Clean Water Act. The NPDES program functions as the 

primary regulatory tool for ensuring compliance with water quality standards. NPDES permits, 

issued by either EPA or an authorized state, contain discharge limits designed to meet water 

quality standards and national technology-based effluent regulations. 

In 1987, in view of the progress achieved in controlling point sources and growing national 

awareness of the increasingly dominant influence of NPS pollution on water quality, Congress 

amended the Clean Water Act to focus greater national efforts on nonpoint sources. Under this 

amended version, referred to as the 1987 Water Quality Act, Congress revised Section 101, 

“Declaration of Goals and Policy,” to add the following fundamental principle: 

It is the national policy that programs for the control of nonpoint sources of 

pollution be developed and implemented in an expeditious manner so as to enable 

the goals of this Act to be met through the control of both point and nonpoint 

sources of pollution. 

The Water Quality Act of 1987 also included language that required comprehensive storm water 

regulation using a two-phased approach. (Detailed information on both phases of the NPDES 

Storm Water Program is available at http://www.epa.gov/npdes/stormwater.) Phase I, in place 

since 1990, required operators of medium and large municipal separate storm sewer systems 

(MS4s) located in incorporated areas and counties with populations of more than 100,000, 

certain industrial activities, and construction activities disturbing 5 acres or more to obtain an 

NPDES permit to discharge storm water runoff. In October 1999 EPA expanded the federal 

storm water program with the promulgation of the Phase II rule. 

Phase II requires operators of small MS4s (non-Phase I regulated MS4s) in “urbanized areas” (as 

defined by the Bureau of the Census) and small construction activities disturbing between 1 and 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

5 acres of land to obtain an NPDES permit. Further, the NPDES permitting authority may 

require operators of small MS4s not in urbanized areas and small construction activities 

disturbing less than 1 acre to obtain an NPDES permit based on the potential for contribution to a 

violation of a water quality standard. NPDES permitting authorities are required under the rule to 

assess for potential designation all small MS4s located outside an urbanized area that are in areas 

with a population of at least 10,000 and a population density of 1,000 per square mile. The Phase 

II rule also includes a revised conditional no-exposure provision for industrial facilities, which 

provides for a waiver from the permit program if the storm water pollutant sources at a facility 

can be demonstrated to be isolated from precipitation and runoff. 

For small MS4 permits, Phase II prescribes a set of six minimum control measures, as well as 

requirements for evaluation and assessment efforts. The minimum measures are: (1) public 

education and outreach on storm water impacts; (2) public involvement/participation; (3) illicit 

discharge detection and elimination; (4) construction site runoff control; (5) postconstruction 

storm water management in new development and redevelopment; and (6) pollution 

prevention/good housekeeping for municipal operations. The regulated operators must choose 

and implement appropriate best management practices (BMPs) and define measurable goals for 

each measure. The operators must also periodically evaluate and assess program compliance, the 

appropriateness and effectiveness of their chosen BMPs, and progress toward achieving their 

identified measurable goals. This guidance is expected to be consistent with any guidance issued 

for regulated small MS4 operators to meet the requirements of Phase II NPDES storm water 

discharge permits. Therefore, the management measures and practices herein can serve as a 

resource in developing a community’s storm water management program. It is important to note, 

however, that additional requirements not addressed in this guidance may be imposed under an 

NPDES storm water permit. Table 0.3 specifies how the management measures relate to each of 

the six minimum control measures. 

0-8 
Introduction 

Table 0.3: Comparison of management measures to the six minimum control measures of 

NPDES Phase II. 

Public Education Public Involvement Illicit Discharge Construction Site ESC Post Construction Pollution Prevention 

Program Framework and Objectives 

Establish Legal Authority 9 9 9 9

Develop an Institutional Structure 

Provide Adequate Funding and Staffing 

Foster Input From Technical Experts, Citizens, and 

Stakeholders 

9

Establish Intergovernmental Coordination 9

Develop Training and Education Programs and Materials 9 9

Watershed Assessment 

Characterize Watershed Conditions 

Assess Cumulative Effects 

Estimate the Effectiveness of Treatment Programs 

Establish a Set of Watershed Indicators 

Establish Water Quality Indicators 

Establish Physical and Hydrological Indicators 

Establish Biological Indicators 

Establish Programmatic Indicators 

Develop a Suite of Social Indicators 

Measurable Goals 

Watershed Protection 

Resource Inventory and Information Analysis 9

Development of Watershed Management Plan 9

Implement the Plan 9

Land or Development Rights Acquisition Practices 9

Site Development 

Site Planning Practices 9

On-Lot Impervious Surfaces 9

Residential Street and Right-of-Way Impervious Surfaces 9

Parking Lot Impervious Surfaces 9

Xeriscaping Techniques 9

New Development Runoff Treatment 

Infiltration Practices 9

Vegetated Open Channel Practices 9

Filtering Practices 9

Detention and Retention Practices 9

Other Practices 9

New and Existing Onsite Wastewater Treatment Systems 

Permitting and Installation Programs 9 9

Operation and Maintenance Programs 9 9

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Table 0.3 (continued). 

Public Education Public Involvement Illicit Discharge Construction Site ESC Post Construction Pollution Prevention 

Bridges and Highways 

Site Planning and Design Practices 9

Soil Bioengineering and Other Runoff Controls for 

Highways 9

Structural Runoff Controls for Bridges 9

Bridge Operation and Maintenance Controls 9

Nonstructural Runoff Control Practices 9

Construction Site Erosion, Sediment, and Chemical Control 

Erosion and Sediment Control Programs 9

Erosion Control Practices 9

Sediment Control Practices 9

Develop and Implement Programs to Control Chemicals 

and Other Construction Materials 

9

Pollution Prevention 

Household Chemicals 9 9 9

Lawn, Garden, and Landscape Activities 9 9 9

Commercial Activities 9 9 9 9

Trash 9 9 9

Nonpoint Source Pollution Education for Citizens 9 9

Existing Development 

Identify, Prioritize, and Schedule Retrofit Opportunities 9

Implement Retrofit Projects as Scheduled 9

Restore and Limit the Destruction of Natural Runoff 

Conveyance Systems 

9

Restore Natural Streams 9

Preserve, Enhance, or Establish Buffers 9

Redevelop Urban Areas to Decrease Runoff-Related 

Impacts 

9

Operation and Maintenance 

Establishing an Operation and Maintenance Program 9 9

Source Control Operation and Maintenance 9 9

Treatment Control Operation and Maintenance 9 9

Evaluate Program Effectiveness 

Assess the Runoff Management Program Framework 

Track Management Practice Implementation 

Gauge Improvements in Water Quality Resulting from 

Management Practice Implementation 

Develop and Implement a Schedule to Improve the 

Management Program Framework 

Measurable Goals 

0-10 
Introduction 

The Clean Water Act establishes several reporting, funding, and regulatory programs that 

address pollutants carried in runoff that is not subject to confinement or treatment. These 

programs relate to watershed management and urban NPS control. Readers are encouraged to use 

the information contained in this guidance to develop nonpoint source management 

programs/plans that comprehensively address the following EPA reports and programs: 

— Section 303(d) Lists and TMDLs. Under section 303(d) of the Clean Water Act, states are 

required to compile a list of impaired waters that fail to meet any of their applicable water 

quality standards or cannot support their designated or existing uses. This list, called a 

“303(d) list,” is submitted to Congress every two years, and states are required to develop 

a Total Maximum Daily Load (TMDL) for each pollutant causing impairment for water 

bodies on the list. More information on the TMDL program and 303(d) lists is provided 

at http://www.epa.gov/owow/tmdl. 

— Section 305(b) and the National Water Quality Inventory: Report to Congress. Every two 

years, states are required to submit a report to Congress detailing the health of their 

waters. These periodic reports allow Congress to gauge progress toward meeting the 

goals of the Clean Water Act and to help identify priorities for future pollution control 

funding and activities. More information on the 305(b) program and the National Water 

Quality Inventory is provided at http://www.epa.gov/owow/305b. 

— Section 319 Grant Program. Under Section 319 of the Clean Water Act, EPA awards 

funds to states and eligible tribes to implement NPS management programs. These funds 

can be used for projects that address urban sources of pollution. More information about 

the Section 319 program is provided at http://www.epa.gov/owow/nps/cwact.html. 

— Section 404 Discharge of Dredged and Fill Material. Under Section 404 of the Clean 

Water Act, persons planning to discharge dredged or fill material to wetlands or other 

waters of the United States generally must obtain authorization for the discharge from the 

U.S. Army Corps of Engineers (Corps), or a state approved to administer the Section 404 

program. Such authorization can be through issuance of an individual permit, or may be 

subject to a general permit, which applies to certain categories of activities having 

minimal adverse environmental effects. Implementation of Section 404 is shared between 

the Corps and EPA. The Corps is responsible for reviewing permit applications and 

deciding whether to issue or deny permits. EPA, in consultation with the Corps, develops 

the Section 404(b)(1) Guidelines, which are the environmental criteria that the Corps 

applies when deciding whether to issue permits. EPA also has authority under Section 

404(c) to "veto" Corps issuance of a permit in certain cases. More information about the 

404 program is provided at http://www.epa.gov/owow/wetlands. 

— Clean Water State Revolving Fund. EPA established the Clean Water State Revolving 

Fund (CWSRF) to provide states with low- or no-interest loans for projects that improve 

water resources. These funds can be used to support urban NPS pollution programs and 

projects. To receive CWSRF loans from EPA for water quality projects, states must 

develop annual Intended Use Plans that outline the expected use of these funds. More 

information on the CWSRF program is provided at http://www.epa.gov/OWM/finan.htm. 

— National Estuary Program. Under the National Estuary Program, states work together to 

evaluate water quality problems and their sources, collect and compile water quality data, 

 0-11 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

and integrate management efforts to improve conditions in estuaries. So far 28 estuaries 

have been accepted into the program. Estuary programs can be an excellent source of 

water quality data and can provide information on management practices. More 

information on the National Estuary Program is provided at 

http://www.epa.gov/owow/estuaries/nep.html. 

Two excellent resources for learning more about the Clean Water Act and the many programs 

established under it are The Clean Water Act: An Owner’s Manual (Elder et al., 1999) and The 

Clean Water Act Desk Reference (WEF, 1997). 

Safe Drinking Water Act. Many urban areas, especially urban fringe areas, need to maintain or 

improve the quality of surface and ground waters that are used as drinking water sources. This 

act requires states, among other things, to develop Source Water Assessment Reports and 

implement Source Water Protection Programs. Low- or no-interest loans are available under the 

Drinking Water State Revolving Fund Program. More information about the Safe Drinking 

Water Act and Source Water Protection Programs can be found at 

http://www.epa.gov/safewater/protect.html.

0.3 Key Concepts 

0.3.1 Watershed Approach 

Since 1991, EPA has promoted the watershed approach as the key framework for dealing with 

problems caused by urban runoff and other sources that impair surface and ground waters 

(USEPA, 1998). Five principles guide the watershed approach: 

— Place-based focus. Activities are directed within specific geographic areas known as 

management units. When surface runoff is the primary issue, these management units are 

defined by watershed boundaries. Other types of boundaries can also be used to define 

management units in special circumstances. If ground water is an issue, for example, 

ground water recharge areas might be a logical designation.

— Stakeholder involvement and partnerships. The people most affected by management 

decisions are involved throughout the process. Stakeholder participation helps to ensure 

that local quality of life, economic stability, and other important community issues are 

incorporated into planning and implementation activities. Partnerships among public 

agencies and private groups at all levels are also crucial for long-term success. 

— Environmental goals and objectives. The success of watershed initiatives is measured by 

improvements of the water resource rather than by programmatic objectives. For 

example, reestablishing the pool and riffle structure in a stream channel to increase 

aquatic insect and fish populations might be an objective. Local goals and objectives need 

to be consistent with all applicable state, tribal, and federal statutes and regulations, 

including water quality standards. 

— Problem identification and prioritization. Sound scientific data and methods are used to 

identify and prioritize threats to human and ecosystem health. This process usually begins 

0-12 
Introduction 

with the assessment and characterization of current natural resource and community 

conditions within the management unit(s). Problems, including their causes and sources, 

are also documented. Stakeholders and partners then work jointly to set priorities among 

the various water resource concerns, taking into account priorities already established at 

scales above and below the management unit. 

— Integration of actions. Stakeholders and partners take actions in a comprehensive and 

integrated manner. Results are then evaluated and actions are adjusted as needed. 

A key attribute of the watershed approach is that it can be applied with equal success to largeand small-scale watersheds. Federal agencies, states, interstate commissions, and tribes usually 

apply the approach on watersheds of approximately 100 square miles. Local agencies and urban 

communities, however, can apply the approach to watersheds as small as 1 square mile. 

Although specific objectives, priorities, actions, timing, and resources might vary from large 

scale to small scale, the basic goals of the watershed approach remain the same—protecting, 

maintaining, and restoring water resources. 

Local runoff management program officials must be especially conscious of watershed scale 

when planning and implementing specific management practices. Nonstructural practices, such 

as stream protection ordinances and public education campaigns, are usually applied communitywide. Consequently, the results benefit many small watersheds. In contrast, structural practices, 

such as infiltration basins and sand filters, usually provide direct benefits to a single stream. 

Regional structural management practices such as retention ponds for larger watersheds can be 

used, but they do not protect smaller contributing streams. Given limited resources, runoff 

program officials must often analyze costs and benefits and choose between large- and smallscale practices. Often, a combination of nonstructural and structural practices is the most costeffective approach. 

The Province of British Columbia has taken a watershed approach in planning for water quality 

protection through runoff volume management. Program officials have recognized the link between 

surface water volume and watershed health, and are incorporating land use planning into urban runoff 

management efforts. The Water Balance Model is a decision support tool developed to assist in the 

integration of land use planning and urban runoff management by simulating the effects of source 

controls within the watershed. This tool allows the province to establish priorities and efficiently 

evaluate the potential effectiveness of management efforts (Stephens et al., 2003). 

British Columbia’s Watershed Approach

0.3.2 Stream Network 

The size of a watershed is closely related to the network of streams contained within its borders. 

Streams with no upstream tributaries are designated as first-order streams down to their first 

confluence. A second-order stream is formed when two first-order streams meet. A third-order 

stream is created by the confluence of two second-order streams, and so on. 

Headwater streams are defined as first- and second-order streams. What they lack in individual 

size and length, they make up through sheer numbers. Headwater streams dominate the 

landscape, accounting for roughly 75 percent of the total stream and river mileage in the United 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

States (Table 0.4). Because they are the dominant drainage feature, headwater streams also 

directly receive the bulk of runoff from construction sites, developments, parking lots, highways, 

and other features of the urban landscape. In most communities, runoff is collected by a storm 

sewer system and discharged with no treatment. Increases in the volume and rate of storm water 

runoff have historically resulted in construction of concrete channels and drainage pipes, 

eliminating many headwater streams. 

Table 0.4: National stream order statistics (Leopold et al., 1964). 

Stream 

Order Number of Streams

Total Length 

of Stream Miles

Mean Drainage Area 

(square miles)

1 1,570,000 1,570,000 1 

2 350,000 810,000 4.7 

3 80,000 420,000 23 

4 18,000 220,000 109 

5 4,200 116,000 518 

6 950 61,000 2,460 

7 200 30,000 11,700 

8 41 14,000 55,600 

9 8 6,200 264,000 

10 1 1,800 1,250,000

0.3.2.1 Watershed scales 

Any number of watersheds can be defined by the streams within the network. Larger watersheds 

encompass progressively smaller watersheds in a hierarchical manner. Larger watershed scales, 

or national scales, are classified using the Hydrologic Unit Code (HUC), a system of hierarchical 

codes used by federal agencies, states, interstate commissions, tribes, and others to identify 

watersheds at the national level. Smaller local watersheds, existing at scales below the smallest 

HUC scale, are identified more informally. 

The U.S. Geological Survey (USGS) has developed the National Hydrography Dataset (NHD), 

which is a comprehensive set of digital spatial data derived from USGS digital line graphs and 

EPA's reach file 3 that contains information about surface water features such as lakes, ponds, 

streams, rivers, springs, and wells. Within the NHD, surface water features are combined to form 

“reaches,” which provide the framework for linking water-related data to the NHD surface water 

drainage network. These linkages enable the analysis and display of these water-related data in 

upstream and downstream order. More information about the NHD is provided at 

http://nhd.usgs.gov. 

0.3.2.2 National-level scales 

USGS developed the HUC system for the purpose of inventorying all “national scale” 

watersheds in the United States. To accomplish this objective the agency first divided the 

country into 21 regions that account for the watersheds of 21 major river basins. Within those 

major river basins the agency identified a total of 222 watershed subregions. The subregions, in 

turn, were classified as 352 accounting units. The accounting units were further broken down 

into 2,262 smaller watersheds called cataloging units. 

0-14 
Introduction 

Each level, or scale, in the watershed hierarchy is identified by a numerical code. The cataloging 

unit, the smallest scale in the hierarchy, has an eight-digit code that uniquely identifies its 

location. The region where the cataloging unit resides is designated by the first two digits of the 

code, the subregion by the second two digits, and so on until the four scales are identified. For 

example, the watershed of the Upper Mississippi River at Hasting, Minnesota, has a HUC code 

of 07010206. This code breaks down as follows: 

Major River Basin ID 07 

Subbasin ID 0701 

Accounting Unit ID 070102 

Catalog Unit ID 07010206 

0.3.2.3 Local-level scales 

The hierarchy established by the HUC system identifies scales useful for watershed planning and 

management by national, regional, state, and multi-state jurisdictions. In many instances, a 

municipality or urban community is part of a larger team and undertakes activities in a largescale context. However, because even the smallest scale, the cataloging unit, usually describes 

watersheds of 100 to 1,000 square miles, local practitioners of runoff management typically find 

the HUC-designated scales simply too large to be of practical use. This is especially true when 

designing and implementing runoff control practices for individual developments and sites. 

Consequently, the watershed hierarchy must be extended to include smaller-scale management 

units. A national effort is under way to designate 14-digit HUCs. 

The Center for Watershed Protection (Caraco et al., 1998) proposed three progressively smaller 

scales in the watershed hierarchy below the subbasin cataloging unit (Figure 0.3): 

— Watershed. The scale encompassed by the cataloging unit. Generally, this is the largest 

management unit that falls within the local land use planning authority. A community 

might have one or more watersheds within its borders, depending on its size.

— Subwatershed. The scale encompassed by the watershed. Its boundaries include all the 

land area draining to the point where two second-order streams come together to form a 

third-order stream. In most regions, subwatersheds are a few square miles in area and are 

drained by a stream several feet in width. 

— Catchment. The smallest scale in the hierarchy. The Center for Watershed Protection 

defines it as the area that drains an individual development site to its first intersection 

with a stream. In some cases this intersection is in the form of a pipe outfall. Depending 

on the size of the development site, the catchment might also include some off-site 

drainage. 

 0-15 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

CATCHMENT

SUBWATERSHED

WATERSHED

8-DIGIT CATALOGING UNIT

SUB-BASIN

BASIN

Figure 0.3: Scales of watershed management units (Schueler, 1995). 

0.3.3 Impervious and Pervious Surfaces in the Urban Landscape 

The term impervious surface refers to land cover, both natural and human-made, that cannot be 

penetrated by water. Consequently, precipitation that falls on impervious surfaces does not 

infiltrate into the soil. Instead, it runs off to a pervious area where all or a portion infiltrates into 

the soil, or it continues to travel down-slope on impervious surfaces including saturated soils 

until it is eventually conveyed to a ditch, a storm drain network, a stream, a lake, a wetland, an 

estuary, or some other type of surface receiving water. For additional discussion on the water 

quality impacts of imperviousness, see Section 1.3.5, Changes in the Watershed Due to Increased 

Imperviousness. 

Most of the impervious cover in an urban watershed or subwatershed can be organized into three 

main categories: 

— Rooftops. Impervious cover created by buildings, homes, garages, stores, warehouses, 

and other structures with roofs.

— Transport systems. Impervious cover created by structures such as roads, sidewalks, 

driveways, and parking lots. Most of these structures are associated with transportation of 

people or materials, hence the name transport systems. 

0-16 
Introduction 

— Recreational facilities. Impervious cover created by tennis and basketball courts, 

playgrounds, decks, and swimming pools. 

In most areas the transport systems component covers a larger percentage of land than the 

rooftops component. A study in the city of Olympia, Washington, for example, revealed that 

transport system imperviousness constituted 63 to 70 percent of the total impervious cover at 11 

sites of varying land use, including residential, multifamily, and commercial areas (City of 

Olympia, 1995). 

0.3.3.1 Total and effective impervious surface 

The amount of impervious cover in a watershed or subwatershed is reported in two basic ways: 

— Total (or mapped) impervious area. Includes all impervious cover in a watershed or 

subwatershed—rooftops, transport systems, and recreational facilities. It is usually 

expressed as a percentage of the total watershed or subwatershed area. It can be 

calculated by direct measurement or by percentage estimation based on land use, road 

density, population density, or another indicator. 

— Effective impervious area (EIA). The portion of total impervious cover that is directly 

connected to the storm drain network (Sutherland, 1995). These surfaces usually include 

street surfaces and paved driveways and sidewalks connected to or immediately adjacent 

to them, parking lots, and rooftops that are hydraulically connected to the drainage 

network (e.g., downspouts running directly to gutters or driveways). EIA also is usually 

expressed as a percentage of the total watershed or subwatershed area. It is the preferred 

statistic for use when estimating runoff volumes because it is the portion of the 

impervious cover that generates direct runoff. 

Subtracting EIA from the total impervious area yields the amount of impervious area that is not 

directly connected to the storm drain network, or the ineffective impervious area. Residential 

rooftops are an example of possible ineffective impervious areas because downspouts can direct 

runoff to yards and other pervious landscaping areas, where a portion of the water can infiltrate 

the ground. Rooftops in some residential and most commercial areas, however, will likely be 

classified as effective impervious areas because their downspouts typically will be tied directly 

to the storm drain network. Filtration, infiltration, evaporation, and biological uptake of 

pollutants can substantially reduce runoff volume and improve water quality when runoff is 

directed over vegetated areas. For further discussion on downspout disconnection, see 

Management Measure 4: Site Development and Management Measure 10: Existing 

Development. 

Both the amount of impervious area and the relationship between total and effective impervious 

areas varies according to land use (Caraco et al., 1998). For example, work in the Puget Sound 

area revealed that total impervious area in low-density residential sites averaged approximately 

10 percent, with an effective impervious area of only 4 percent. In commercial and industrial 

areas, however, total impervious area averaged about 90 percent. Almost all of the total 

impervious area is also effective impervious area because of the lack of pervious areas to break 

up direct connections. 

 0-17 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

0.3.3.2 Pervious surfaces 

The urban and suburban landscape has a variety of pervious surfaces, including 

— Forests and wetlands 

— Lawns and other private turf 

— Public turf 

— Intensively landscaped areas 

— Vacant lands 

— Runoff treatment areas 

Although most of these areas are green, it would be a mistake to think of them as hydrologically 

equivalent to an undisturbed meadow, forest, or other natural pervious area, especially in terms 

of their ability to allow runoff to infiltrate. Soils in urban landscapes are usually highly disturbed 

and compacted, poor in structure, and low in permeability. In addition, they often receive runoff 

from adjacent impervious areas, resulting in water inputs many times greater than normal. These 

factors and others tend to decrease the ability of pervious urban areas to infiltrate runoff, which 

means an increased fraction of water moves off these areas to impervious areas and storm 

drainage networks. In extreme cases, the amount of runoff generated is close in volume to that 

generated from impervious surfaces. Consequently, some “pervious” areas function as 

impervious areas and cause analysts to underestimate peak flow, runoff volumes, and time of 

concentration. Refer to Management Measure 9: Pollution Prevention, for more information on 

runoff from lawns. 

0.3.4 Impervious Cover Model 

A simple tool, the Impervious Cover Model, can be used to project the current and future quality 

of streams and other water resources at the subwatershed scale based on impervious cover 

(Caraco et al., 1998). The objective of this model is to assist local officials and other watershed 

practitioners in devising realistic goals and objectives given present and future levels of 

development. The impervious cover model is a simple urban stream classification system that 

contains three stream categories based on the percentage of impervious cover present in the 

subwatershed. It is intended to help managers decide how to adapt and refine management 

measures given the intensity of urban development in their watersheds. The impervious cover 

model has some limitations. These are (Caraco et al., 1998): 

— Reference condition. The model predicts potential, not actual, stream quality, so in some 

cases stream reaches might depart from the model’s predictions. 

— Scale effect. The model should be applied only to small, first- to third-order streams 

because the influence of impervious cover is strongest at these spatial scales. 

— Statistical variability. There is a moderate degree of scatter exhibited in individual 

impervious cover/stream quality indicator relationships, although the indicators show a 

general downward trend as imperviousness increases. The model predicts the average 

behavior of multiple indicators over a range of imperviousness, and the impervious cover 

thresholds are not sharp breakpoints but transitions. 

0-18 
Introduction 

— Measuring and projecting impervious cover. Accurately quantifying actual and projected 

impervious cover is important for the model. However, there is no standardized method 

for measuring total or effective imperviousness.

— Regional adaptability. The model has been tested mostly in the mid-Atlantic and Puget 

Sound ecoregions but little research has been conducted to determine the applicability of 

the model in western, midwestern, and mountain streams. 

— Defining thresholds for nonsupporting streams. More sampling and study are needed to 

more firmly establish the threshold for the transition between impacted streams and 

nonsupporting streams, projected to occur at 25 percent impervious cover for small urban 

streams. 

— Influence of management practices in extending thresholds. The changes in hydraulic and 

pollutant loadings, and their effects on receiving streams, should be carefully considered 

when practices are used to extend the threshold of imperviousness.

— Influence of riparian cover in extending thresholds. Conservation or restoration of a 

riparian zone has been shown to extend the impervious cover threshold. 

— Pervious area. Urban landscapes contain pervious areas, but many of them are highly 

disturbed and do not resemble pervious areas in non-urban landscapes. However, 

planners can integrate pervious and impervious areas to greatly reduce effective 

impervious area and reduce the impact of imperviousness on stream quality. 

0.3.4.1 Subwatersheds as the primary management unit 

The impervious cover model relies on the subwatershed as the primary management unit. Table 

0.5 displays the influence of impervious cover in the context of a hierarchy of watershed-based 

management units. The subwatershed scale is ideal for planning purposes at the local level for 

many reasons, including: 

— The influence of impervious cover on hydrology, channel stability, water quality, and 

biodiversity is most evident at the subwatershed scale because the receiving water body is 

typically a headwater stream. 

— The smaller scale helps local officials more easily identify impacts of individual 

development projects and sources of pollutants. 

— Subwatersheds are typically small enough to be within the borders of one or two 

jurisdictions. This eases the burden of establishing regulatory authority as well as keeping 

the number of stakeholders to a manageable number. 

— Assessments and evaluations can be conducted more easily because most subwatersheds 

can be mapped on a standard 24-inch by 36-inch sheet with sufficient detail to provide 

useful management information. The smaller scale also allows assessments and 

evaluations to be completed more rapidly than similar efforts at larger scales. This creates 

the opportunity for phasing the development of subwatershed plans (or focusing on areas 

 0-19 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

needing priority attention), making the best use of limited resources. Officials and local 

citizens can more easily recognize progress as plans are completed and implemented over 

a coordinated cycle. 

Table 0.5: Idealized characteristics of five watershed management units with respect to size 

and the influence of impervious cover (adapted from Caraco et al., 1998). 

Watershed Management Unit Typical Area (square miles) Influence of Impervious Cover 

Catchment 0.05–0.50 Very strong 

Subwatershed 1–10 Strong 

Watershed 10–100 Moderate 

Subbasin 100–1,000 Weak 

Basin 1,000–10,000 Very weak 

0.3.4.2 Classification levels 

The impervious cover model designates three levels of classification based on impervious cover: 

— Sensitive subwatersheds, which have less than 10 percent impervious cover. Streams 

found in sensitive subwatersheds are at, or close to, predevelopment conditions. Urban 

runoff management strategies, therefore, should focus on maintaining these conditions. 

New development and redevelopment should be discouraged or designed to have no 

impact to prevent any increase of impervious cover in subwatersheds of this type. 

— Degrading subwatersheds, which have 11 to 25 percent impervious cover. Degrading 

subwatersheds have crossed the 10 percent imperviousness threshold, and have 

experienced degradation of key stream attributes or can be expected to experience such 

degradation over time. Some of the more sensitive organisms probably have disappeared 

or will disappear. Resource objectives consequently should focus more on maintaining or 

restoring key conditions than on resource protection as a whole. Structural and 

nonstructural practices that deal with, or counteract, increased urban runoff are 

recommended.

— Nonsupporting subwatersheds, which have more than 25 percent impervious cover. 

Streams in nonsupporting subwatersheds are well beyond the impervious cover 

thresholds and may never recover predevelopment conditions no matter how many 

management practices are implemented. Resource objectives are primarily aimed at 

reducing peak flows and preventing and removing urban pollutants so they will not be 

carried downstream. Limited restoration of some attributes such as increased biodiversity 

can sometimes be achieved given the right circumstances. Pollution prevention and 

retrofitting in existing urban areas are the most frequently used practices. 

Table 0.6 describes channel stability, water quality, and biodiversity attributes, as well as general 

resource and water quality objectives associated with each category. 

0-20 
Introduction 

Table 0.6: Characteristics of aquatic integrity in urban watersheds. 

Integrity Rating Low Moderate High

Riparian Habitat 

Characteristics 

— Riparian zone greatly 

reduced 

— Increased sediment 

deposition 

— Completely bare/exposed 

banks 

— Deeply incised and 

widened channel crosssection 

— Riparian zone partly 

cleared 

— Moderate sediment 

deposition, sand bar 

formation 

— Banks slightly exposed 

— Steep banks and widened 

channel cross-section 

— Mature riparian zone 

— Decreased sediment 

deposition, mostly 

rocky substrates 

— Bank well-vegetated 

and forested 

— Floodplain terrace 

channel cross-section 

Macroinvertebrate 

Community 

Characteristics 

— Pollution-tolerant species 

— Tolerant of low dissolved 

oxygen (DO) levels 

— Reduced feeding and life 

history requirements 

— Decreased diversity and 

number of species 

— Moderately pollutiontolerant species 

— Tolerant of moderate DO 

levels 

— Some general reduction 

in life history and 

feeding requirements 

— Pollution-intolerant 

species 

— Intolerant of low DO 

levels 

— Unaltered life history 

and feeding 

requirements 

— Increased number and 

diversity of species 

Fish Assemblage 

Characteristics 

— Pollution-tolerant species 

— Exotic/introduced species 

— Reduced feeding and life 

history requirements 

— Decreased diversity and 

number of species 

— Moderately pollutiontolerant species 

— Intermediate number of 

individuals and species 

— Some general reduction 

in life history and 

feeding requirements 

— Pollution-intolerant 

species 

— Unaltered life history 

and feeding 

requirements 

— Increased number and 

diversity of species 

Rehabilitation 

Process 

Degraded Improved

0.3.5 Changes in the Watershed Due to Increased Imperviousness 

Watershed imperviousness plays an important role in determining the conditions in streams and 

other bodies of water. Impervious cover, however, is an inescapable attribute of development and 

a permanent part of the urban/suburban landscape. Figure 0.4 illustrates how four important 

components in the water cycle are affected by increasing levels of imperviousness (FISRWG, 

1998). In natural landscapes, there is usually very little or no surface runoff. Water either 

percolates into the ground or is returned to the atmosphere by evaporation and transpiration. As 

imperviousness increases: 

— Runoff increases because the surface area of rooftops and transportation systems is 

increased. 

— Soil percolation decreases because pervious areas are reduced. 

 0-21 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Figure 0.4: Impacts of urbanization on the water cycle (Adapted from FIRSWG, 1998). 

40%

evapotranspiration

10%

runoff

25% shallow

infiltration

25% deep

infiltration

38%

evapotranspiration

20%

runoff

21% shallow

infiltration

21% deep

infiltration

35%

evapotranspiration

30%

runoff

20% shallow

infiltration 15% deepinfiltration

30%

evapotranspiration

55%

runoff

10% shallow

infiltration 5% deepinfiltration

Natural Ground Cover 10%-20% Impervious Surface

35%-50% Impervious Cover 35%-50% Impervious Cover

— Evaporation decreases because there is less time for it to occur when runoff moves 

quickly off impervious surfaces. 

— Transpiration decreases because vegetation has been removed. 

As might be expected, there is a linear relationship between the amount of impervious surfaces in 

a given area and the amount of runoff generated. What is unexpected is what this means in terms 

of both the volume of water generated and the rate at which it exits the surface. Depending on 

the degree of impervious cover, the annual volume of storm water runoff can increase to 

anywhere from 2 to 16 times the predevelopment amount (Schueler, 1994). Impervious surface 

coverage as low as 10 percent can destabilize a stream channel, raise water temperature, and 

reduce water quality and biodiversity (Schueler, 1995). One recent study found that connected 

imperviousness levels between 8 and 12 percent represented a threshold region where minor 

changes in urbanization could result in major changes in stream condition (Wang et al., 2001). 

Figure 0.5 shows a hydrograph comparing stream flow rates before, during, and after a storm 

under pre- and postdevelopment conditions (Schueler, 1987). As indicated, streams with 

developed watersheds have substantially higher peak flows, and these peak flows occur more 

quickly than under predevelopment conditions. This is reflective of typical urban conditions, 

where runoff moves quickly over impervious surfaces and drains into a channel. 

0-22 
Introduction 

Large

Storm

Small

Storm

Higher Baseflow

Higher and More

Rapid Peak Discharge

More Runoff Volume

Lower and Less

Rapid Peak

Gradual

Recession

Pre-development

Post-development

Figure 0.5: Changes in stream flow hydrograph as a result of urbanization (Schueler, 

1987). 

Development and increased impervious cover also lead to erosion and undercutting of 

streambanks, widening of channels, and depositing of in-channel sediment. In addition, 

decreased base flow occurs in dry weather because a greater portion of runoff flows off the 

Floodplain Limit

Summer Low Flow Level

Pre-Development Condition

Floodplain Limit

Summer Low Flow Level Summer Low Flow Level

Post-Development Condition

Figure 0.6: Response of stream geometry to urbanization (Schueler, 1987). 

 0-23
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

surface, resulting in less infiltration to ground water reserves that normally provide base flow to 

streams. Figure 0.6 shows changes to stream geometry in response to urbanization (Schueler, 

1987). 

EPA (1997) reviewed the literature for case studies that quantitatively examined the relationship 

between increased impervious surfaces and stream impacts. Table 0.7 lists these relationships, 

and Table 0.8 summarizes the case studies used to derive the relationships. 

Table 0.7: Impacts from increases in impervious surfaces (USEPA, 1997). 

Resulting Impacts

Increased 

Imperviousness Leads to: Flooding

Habitat 

Loss Erosion

Channel 

Widening

Streambed 

Alteration

Increased Volume T T T T T

Increased Peak Flow T T T T T

Increased Peak Duration T T T T T

Increased Stream Temperature T

Decreased Base Flow T

Sediment Loading Changes T T T T T

Table 0.8: Summary of case studies linking urbanization to hydrological impacts on 

streams (USEPA, 1997). 

Case Study Location Documented Impacts Inferred Impacts

East Meadow Brook Nassau County, 

NY 

— Increased peak flows Flooding, habitat loss, 

erosion, channel widening, 

streambed alteration 

Holmes Run Watershed Fairfax, VA — Frequent flooding 

— Severe streambank erosion 

— Sedimentation 

Flooding, habitat loss, 

erosion, channel widening, 

streambed alteration 

Kelsey Creek Bellvue, WA — Degradation of designated 

uses 

— Decreased base flow 

— Loss of fish populations 

Habitat loss, channel 

widening 

Patuxent River System Maryland — Increased instream sediment 

load 

— Changes in morphology of 

urban channels 

Habitat loss, erosion, 

channel widening 

Peachtree Creek Atlanta, GA — Increased bankfull events 

— Decreased base flow 

Flooding, habitat loss, 

erosion, channel widening, 

streambed alteration 

Pheasant Branch Basin Middleton, WI — Stream incision 

— Increase in bankfull events 

— Sedimentation 

Flooding, habitat loss, 

erosion, channel widening, 

streambed alteration 

Pipers Creek Seattle, WA — Increased peak flows 

— Loss of fish populations 

— Aesthetic degradation 

Flooding, habitat loss, 

erosion, channel widening, 

streambed alteration 

Several creeks Dekalb County, 

GA 

— Stream enlargement 

— Stream incision 

— Increased sediment transport 

Habitat loss, erosion, 

channel widening, 

streambed alteration 

Valley Stream, Pines 

Brook, Bellmore Creek, 

and Massapequa Creek 

Nassau County, 

NY 

— Decreased base flow Habitat loss

0-24 
Introduction 

Recent research has shown that streams in urban watersheds have a fundamentally different 

character from that of streams in forested, rural, or even agricultural watersheds. The amount of 

impervious cover in the watershed can be used as an indicator to predict how severe these 

differences might be. In many regions of the country, as little as 10 percent watershed 

impervious cover has been linked to stream degradation, with the degradation becoming more 

severe as impervious cover increases (Schueler, 1995). 

Some key changes in urban streams that merit special attention are detailed below: 

— Bankfull and subbankfull floods increase in magnitude and frequency. The peak 

discharge associated with the bankfull flow (the 1.5- to 2-year return storm) increases 

sharply in magnitude in urban streams. In addition, channels experience more bankfull 

and subbankfull flood events each year and are exposed to critical erosive velocities for 

longer intervals (Booth et al., 1996; Hollis, 1975; and MaCrae, 1996).

— Dimensions of the stream channel are no longer in equilibrium with its hydrologic 

regime. The hydrologic regime that defined the geometry of the predevelopment stream 

channel irreversibly changes, and the stream experiences higher flow rates on a more 

frequent basis. The higher-flow events of the urban stream are capable of moving more 

sediment than before. 

— Channels enlarge. The customary response of an urban stream is to increase its crosssectional area to accommodate the higher flows. This is done by streambed downcutting, 

channel widening, or a combination of both. Urban stream channels often enlarge their 

cross-sectional area by a factor of 2 to 5 depending on the degree of impervious cover in 

the upland watershed and the age of development (Arnold et al., 1982; Gregory et al., 

1992; and Macrae, 1996).

— Stream channels are highly modified by human activity. Urban stream channels are 

extensively modified in an effort to protect adjacent property from streambank erosion or 

flooding. Headwater streams are frequently enclosed within storm drains, while other 

streams are channelized, lined, and/or “armored” by heavy stone. Another modification 

unique to many urban streams is the installation of sanitary sewers underneath or parallel 

to the stream channel. 

— Upstream channel erosion contributes greater sediment load to the stream. The 

prodigious rate of channel erosion coupled with sediment erosion from active 

construction sites increases sediment discharge to urban streams. Researchers have 

documented that channel erosion constitutes as much as 75 percent of the total sediment 

budget of urban streams (Crawford and Lenat, 1989; Trimble, 1997). Urban streams also 

tend to have a higher sediment discharge than non-urban streams, at least during the 

initial period of active channel enlargement.

— Dry weather flow in the stream declines. Because impervious cover prevents rainfall 

from infiltrating the soil, less flow is available to recharge ground water. Consequently, 

during extended periods without rainfall, baseflow levels are often reduced (Simmons 

and Reynolds, 1982).

 0-25 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

— Wetted perimeter of the stream declines. The wetted perimeter of a stream is the 

proportion of the total cross-sectional area of the channel that is covered by flowing water 

during dry weather, and it is an important indicator of habitat degradation in urban 

streams. Given that urban streams develop a larger channel cross-section at the same time 

that their base flow rates decline, it follows that the wetted perimeter will become 

smaller. Thus, for many urban streams, this results in a very shallow, low-flow channel 

that “wanders” across a very wide streambed, often changing its lateral position in 

response to storms. 

— Instream habitat structure degrades. Urban streams are routinely scored as having poor 

instream habitat quality, regardless of the specific metric or method employed. Habitat 

degradation is often exemplified by loss of pool and riffle structure, embedding of 

streambed sediments, shallow depths of flow, eroding and unstable banks, and frequent 

streambed turnover. 

— Large woody debris (LWD) is reduced. LWD is an important structural component of 

many low-order stream systems because it creates complex habitat structure and 

generally makes the stream carry more water. In urban streams, the quantity of LWD 

found in stream channels declines sharply because of the loss of riparian forest cover, 

storm washout, and channel maintenance practices (Booth et al. 1996; May et al., 1997).

— Stream crossings and potential fish barriers increase. Many forms of urban development 

are linear in nature (e.g., roads, sewers, and pipelines) and cross stream channels. The 

number of stream crossings increases in direct proportion to impervious cover (May et 

al., 1997), and many crossings can become partial or total barriers to upstream fish 

migration, particularly if the streambed erodes below the fixed elevation of a culvert or 

pipeline.

— Riparian forests become fragmented, narrower, and less diverse. The important role that 

riparian forests play in stream ecology is often diminished in urban watersheds as tree 

cover is often partially or totally removed along the stream as a consequence of 

development (May et al., 1997). Even when stream buffers are preserved, encroachment 

often reduces their effective width and native species are supplanted by exotic trees, 

vines, and ground covers.

— Water quality declines. The water quality of urban streams during storms is consistently 

poor. Urban storm water runoff contains moderate to high concentrations of sediment, 

carbon, nutrients, trace metals, hydrocarbons, chlorides, and bacteria (Schueler, 1987). 

Although considerable debate exists as to whether storm water pollutant concentrations 

are actually toxic to aquatic organisms, researchers agree that pollutants deposited in the 

streambed exert an undesirable impact on the stream community.

— Summer stream temperatures increase. The impervious surfaces, ponds, and poor 

riparian cover in urban watersheds can increase mean summer stream temperatures by 

2 oF to 10 oF (Galli, 1991). Because temperature plays a central role in the rate and timing 

of instream biotic and abiotic reactions, such increases have an adverse impact on 

streams. In some regions, summer stream warming can irreversibly shift a cold-water 

0-26 
Introduction 

stream to a cool-water or even warm-water stream, resulting in deleterious effects on 

salmonids and other temperature-sensitive organisms. 

— Reduced aquatic diversity. Urban streams are typified by fair to poor fish and 

macroinvertebrate diversity, even at relatively low levels of watershed impervious cover 

or population density (Couch, 1997; Crawford and Lenat, 1989; May et al., 1997; 

Miltner, 2003; Schueler, 1995; Shaver et al., 1994). Declines in sensitive species have 

been observed at levels of impervious cover as low as 4 percent. Impervious cover in 

highly urbanized areas comprising greater than 25 percent of a watershed may even 

preclude the Clean Water Act goal of “fishable” waters (Miltner, 2003). The ability to 

restore predevelopment fish assemblages or aquatic diversity is constrained by a host of 

factors, including irreversible changes in carbon supply, temperature, hydrology, lack of 

instream habitat structure, and barriers that limit natural recolonization. 

Figure 0.7 shows the relationship between impervious cover and aquatic insect diversity; Figure 

0.8 shows the relationship between imperviousness and fish diversity. Both studies were 

conducted in Maryland streams (Schueler and Galli, 1992, as cited in Schueler, 1995). 

40

30 Good

20 Fair

10 Poor

0

0 10 20 30 40 50

% Imperviousness

Metric Values

40

30 Good

20 Fair

10 Poor

0

0 10 20 30 40 50

% Imperviousness

Metric Values

Figure 0.7: Relationship between impervious cover and aquatic insect diversity in 

Anacostia River subwatersheds (Schueler and Galli, 1992, as cited in Schueler, 1995). 

 0-27 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

12

10

6

2

7

5

1

0

Sensitive Species

Total No. of Species

[10%]

[12%]

[25%]

[55%]

0

2

4

6

8

10

12

14

Number of Species

Figure 0.8: Fish diversity in four subwatersheds of different impervious cover in the 

Maryland Piedmont (Schueler and Galli, 1992, as cited in Schueler, 1995). 

0.3.6 Nonpoint Source Pollutants and Their Impacts 

Urban areas are a source for many different types of pollutants. Table 0.9 shows typical pollutant 

concentrations found in storm water. The following discussion identifies the principal types of 

pollutants found in urban runoff and describes their potential adverse effects: 

0.3.6.1 Sediment 

Excessive erosion, transport, and deposition of sediment in surface waters are significant sources 

of pollution in the United States, resulting in major water quality problems. Sediment imbalances 

impair waters’ designated uses. Excessive sediment can impair aquatic life by filling interstitial 

spaces of spawning gravels, impairing sources of fish food, filling rearing pools, and reducing 

beneficial habitat structure in stream channels. In addition, excessive sediment can cause taste 

and odor problems in drinking water supplies and block water intake structures. 

According to the National Water Quality Inventory: 2000 Report to Congress (required under 

section 305(b) of the Clean Water Act), states, tribes, and other jurisdictions surveyed water 

quality conditions in 19 percent of the nation's 3.6 million miles of rivers and streams (USEPA, 

2002b). Some 39 percent of these surveyed waters were impaired by various pollution sources. 

Sediment was the second-leading cause of impairment, accounting for 31 percent of the impaired 

waters. Furthermore, sediment, especially its fine fractions, is the primary carrier of other 

pollutants such as organic components, metals, ammonium ions, phosphates, and toxic organic 

compounds. 

0-28 
Introduction 

Table 0.9: Typical pollutant concentrations found in urban storm water (adapted from 

MDE, 1999, and Terrene Institute, 1994). 

Typical Pollutants Found 

in Storm Water Runoff Units Residentiala Mixeda Commerciala

General 

Urbanb

Total suspended solids mg/L 101 67 69 80c

Total phosphorus mg/L 383 263 201 0.30c

Total nitrogen mg/L – – – 2.0c

Total Kjeldahl nitrogen mg/L 1.9 1.3 1.2 – 

Nitrate + Nitrite :g/L 736 558 572 – 

Total organic carbon mg/L – – – 12.7c

Biological oxygen demand mg/L 10 7.8 9.3 – 

Chemical oxygen demand mg/L 73 65 57 – 

Fecal coliform bacteria MPN/100 mL – – – 3,600c

E. coli bacteria MPN/100 mL – – – 1,450c

Petroleum hydrocarbons mg/L – – – 3.5c

Oil and grease mg/L – – – 2 to 10d

Cadmium :g/L – – – 2c

Copper :g/L 33 27 29 10c

Lead :g/L 144 114 104 18c

Zinc :g/L 135 154 226 140c

Chlorides (winter only) mg/L – – – 230c

Insecticides :g/L – – – 0.1 to 2.0c

Herbicides :g/L – – – 1 to 5.0c

a

 Source: USEPA, 1983. 

b

 These concentrations represent mean or median storm concentrations measured at typical sites and may be greater during 

individual storms. Also note that mean or median runoff concentrations from storm water “hotspots” are 2 to 10 times higher 

than those shown here. Units: mg/L = milligrams/liter, :g/L = micrograms/l, MPN = most probable number. c

 Source: MDE, 1999. 

d

 Source: Terrene Institute, 1994. 

A recent study of the economic impact of excessive erosion and transport of sediment in surface 

water systems estimates the annual cost of damage due to sediment pollution in North America 

at approximately $16 billion (Osterkamp et al., 1998). Sediment pollution costs can be measured 

in physical damages, chemical damages, and biological damages. Physical damages include 

harm to water conveyance, treatment, and storage facilities, and interference with recreational 

and navigational use. Chemical damages include deposition and storage of nutrients, metals, and 

pesticides associated with eroded sediments. Biological damages include harm to aquatic habitat 

from the movement and storage of sediment. 

Potential sources of sediment pollution include agricultural erosion, deforestation, overgrazing, 

silvicultural erosion, urban runoff, construction activities, and mining activities. Sediments can 

also be dislodged and transported directly from the water body's shoreline, bank, or bottom. 

Atmospheric sources might also be a factor. In an informal study of atmospheric deposition of 

dust, Urbonas and Doerfer (2004) found that each 100 ft2 of impervious surface can yield up to 

1 to 1.2 pounds of solids in runoff on an average annual basis. Assuming that all of this dust 

enters storm water and that 30 percent of impervious surfaces are directly connected to the storm 

drain system, the authors estimate that 1 square mile of mixed-use urban development could 

yield 40 to 50 tons of total suspended solids in storm water each year. 

 0-29 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

The following is a summary of impacts of suspended and deposited sediments on the aquatic 

environment (adapted from Schueler, 1997): 

Suspended sediments 

— Abrasion of and damage to fish gills, increasing risk of infection and disease 

— Scouring of periphyton from stream 

— Loss of sensitive or threatened fish species when turbidity exceeds 25 nephelometric 

turbidity units (NTU) 

— Shifts in fish community toward less-diverse, more sediment-tolerant species 

— Decline in sunfish, bass, chum, and catfish when average monthly turbidity exceeds 100 

NTU 

— Reduction in sight distance for trout, with reduction in feeding efficiency 

— Reduction in light penetration, resulting in a reduction in plankton and aquatic plant 

growth 

— Reduction in filtering efficiency of zooplankton in lakes and estuaries 

— Adverse impacts on aquatic insects, which are the base of the food chain 

— Slight increases in stream temperature in summer 

— Particles are a major vector for transport of nutrients and metals 

— Turbidity, which increases probability of boating, swimming, and diving accidents 

— Increased water treatment costs to meet drinking water standards of 5 NTU 

— Increased wear and tear on hydroelectric and water intake equipment 

— Reduction of anglers' chances of catching fish 

— Diminishing quality of direct and indirect recreational experience of receiving waters 

— Decreased submerged aquatic vegetation (SAV) populations 

Deposited sediments

— Physical smothering of benthic aquatic insect community 

— Reduced survival rates for fish eggs 

— Destruction of fish spawning areas and redds 

0-30 
Introduction 

— Imbedding of stream bottom, which reduces fish and macroinvertebrate habitat value 

— Loss of trout habitat when fine sediments are deposited in spawning habitat or riffle-runs 

— Potential for elimination of sensitive or threatened darters and dace from fish community 

— Increase in sediment oxygen demand, which can deplete dissolved oxygen in lakes or 

streams 

— Significant contributing factor in the rapid decline of freshwater mussels 

— Reduced channel capacity, exacerbating downstream bank erosion and flooding 

— Reduced flood transport capacity under bridges and through culverts 

— Loss of storage and lower design life for reservoirs, impoundments, and ponds 

— Dredging costs to maintain navigable channels and reservoir capacity 

— Spoiling of sand beaches 

— Changes in the composition of bottom substrate 

— Coral reef degradation in tropical and subtropical coastal areas 

— Deposits that diminish the scenic and recreational value of waterways 

Additional chronic effects may occur where sediments rich in organic matter or clay are present. 

These enriched depositional sediments may present a continued risk to aquatic and benthic life, 

especially where the sediments are disturbed and resuspended. 

Although most concerns are due to excessive sedimentation, some ecological problems can result 

from insufficient sediment in a water body caused by hydrological modifications. Too little 

sediment can lead to channel scour and destruction of habitat dependent on an optimum level of 

sediment. In lakes, reservoirs, and estuaries, insufficient total suspended sediments can lead to 

increased light levels, resulting in the growth of nuisance algae. 

The term sediment is broadly used to describe a problem associated with suspended solids, 

siltation, erosion, weathering, sedimentation, and other factors. Erosion, sediment transport, and 

deposition are natural processes caused by stresses placed on the earth's surface. Sediment 

movement is the result of water and air moving against the sediment (gravitation stresses) and 

natural weathering (molecular and chemical stresses). Because erosion is a natural process and 

significant quantities of sediments are being moved as a result of natural denudation, it would be 

unrealistic to expect complete control or elimination of sediment loads to receiving waters. 

However, it is feasible to control or manage excessive sediment loadings that have resulted from 

various land use activities and would be detrimental to the quality of the receiving bodies of 

water and to the aquatic and terrestrial habitat. 

 0-31 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

0.3.6.2 Nutrients 

Nutrient overenrichment is especially prevalent in agricultural areas where manure and fertilizer 

inputs to crops significantly contribute to nitrogen and phosphorus levels in streams and other 

receiving waters. Urban streams have been shown to have the second-highest nitrate and total 

phosphorus levels, second only to agricultural streams (Barth, 1995). There are several nonpoint 

sources of nutrients in urban areas, mainly fertilizers in runoff from lawns, pet wastes, failing 

septic systems, and atmospheric deposition from industry and automobile emissions. Deposition 

of airborne pollutants is beyond the scope of this guidance. More information can be found at 

North Carolina State University's Web site, 

http://h2osparc.wq.ncsu.edu/wetland/aqlife/atmosdep.html. 

Excessive nutrient levels in receiving waters can lead to exceedance of drinking water criteria 

(10 mg/L for nitrate-nitrogen), although monitoring data suggest that urban sources of nitrate are 

not high enough to pose a human health risk. However, moderately high concentrations of 

nutrients can result in eutrophication of sensitive receiving waters. These sensitive waters 

include oligotrophic or mesotrophic lakes where phosphorus is a limiting nutrient, or coastal or 

estuarine areas where nitrogen is limiting. Eutrophication can lead to changes in periphyton, 

benthic, and fish communities; extreme eutrophication can cause hypoxia or anoxia, resulting in 

fish kills. Surface algal scum, water discoloration, and the release of toxins from sediment can 

also occur. 

0.3.6.3 Oxygen-demanding substances 

Proper levels of dissolved oxygen (DO) are critical to maintaining water quality and aquatic life. 

Decomposition of organic matter by microorganisms may deplete DO and result in the 

impairment of the water body. Data have shown that urban runoff with high concentrations of 

decaying organic matter can severely depress DO levels after storms. The Nationwide Urban 

Runoff Program (NURP) study (USEPA, 1983) found that oxygen-demanding substances can be 

present in urban runoff at concentrations similar to those in secondary wastewater treatment 

discharges. 

0.3.6.4 Pathogens 

Urban runoff typically contains elevated levels of pathogenic organisms, including bacteria, 

viruses, and protozoa. The bacteria standard is one of the most commonly violated water quality 

standards in terms of both the number of water bodies and stream miles impaired. Approximately 

50 percent of stream miles in Virginia are impaired due to bacteria contamination (Waye, 2002). 

The presence of pathogens in runoff may result in water body impairments such as closed 

beaches and shellfish beds, and contaminated drinking water sources. Pathogen contamination 

related to onsite wastewater treatment systems (OWTSs) has been implicated in a number of 

shellfish bed closings. This problem may be especially prevalent in areas with porous or sandy 

soils and/or shoreline areas with a high concentration of OWTSs. Epidemiological studies have 

shown that pathogens can have significant effects on human health in contaminated marine 

swimming areas (Haile et al., 1999). While the most common effects of bathing in contaminated 

0-32 
Introduction 

water are gastrointestinal illnesses, other conditions affecting the upper respiratory tract, ear, eye, 

and skin may also be contracted (USEPA, 2002a). 

Indicator organisms have long been used to determine the level of risk for contracting illnesses 

from recreational activities in surface waters contaminated by fecal pollution. These organisms 

often do not cause illness directly, but have demonstrated characteristics that make them good 

indicators of harmful pathogens in water bodies. Until 1986, EPA recommended the use of fecal 

coliforms as an indicator for bacteria. However, after conducting epidemiological studies, EPA 

published Ambient Water Quality Criteria for Bacteria, which recommends that states use 

Escherichia coli (E. coli) for fresh recreational waters and enterococci for fresh and marine 

recreational waters because they are better predictors of acute gastrointestinal illness than fecal 

coliforms (USEPA, 1986). Some states and tribes have replaced their fecal coliform criteria with 

water quality criteria for E. coli or enterococci, but many other states and tribes have not yet 

made this transition (USEPA, 2002a). 

Two protozoa of major concern as waterborne pathogens are Giardia lamblia and 

Cryptosporidium parvum. Cryptosporidium has become an increasingly serious pathogen 

problem in urban areas since the 1993 outbreak in Milwaukee, Wisconsin, when pathogens 

passed through a water treatment plant and left 400,000 people ill and almost 100 dead. 

Three major sources of pathogens in urban areas are human waste, pet waste, and anthropogenic 

wildlife. Anthropogenic wildlife includes raccoons, geese, pigeons, seagulls, and rats (Waye, 

2002). Human waste can contaminate urban runoff through illicit connections of sanitary sewers 

with storm water systems, resulting in high bacterial counts and human health risks. These nonstorm water sources are often a major contributor of pathogens to discharges from storm drain 

systems (Pitt et al., 2001). 

While some types of waste can be treated before entering water bodies, others, such as feces 

from pets, should be disposed of properly. When pet waste is not properly disposed of, it can 

wash into nearby water bodies or be carried by runoff into storm drains. Since most urban storm 

drains do not connect to treatment facilities, but rather drain directly into lakes and streams, 

untreated animal feces can become a significant source of pathogens in surface waters. 

As pet waste decays in a water body, it uses up oxygen, sometimes releasing ammonia. Low 

oxygen levels and ammonia combined with warm temperatures can be detrimental to fish and 

aquatic life. Pet waste also contains nutrients that promote weed and algae growth, which can 

cause eutrophication. Perhaps most importantly, pet waste carries bacteria, viruses, and other 

parasites that can pose health risks to humans and wildlife. For more information, refer to the 

discussion of microbial contamination in Management Measure 2: Watershed Assessment, and 

the discussion of pet waste in Management Measure 9: Pollution Prevention. 

0.3.6.5 Road salts 

According to a study by the Department of the Interior and USGS (1996), road salt has become a 

problem for both surface water and ground water quality, especially in the Northeast and 

Midwest. Nationally, an estimated $10 million are spent annually by state and local governments 

to remedy road salt contamination. The Northeastern Illinois Planning Commission (undated) 

estimates that 18 million tons of deicing salt, primarily sodium and calcium chlorides, are used 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

each year in the United States. When the dissolved salts in runoff from highways and bridges 

enter soils, ground water, and surface waters, salinity levels increase and can become toxic to 

plants, fish, and other aquatic organisms. These impacts are especially pronounced in smaller 

water bodies adjacent to salted areas. Additionally, salt is corrosive and may cause damage to 

roadways, bridges, and vehicles. Deicing is very important for pedestrian and driver safety, and 

there are a number of new technologies available for reducing the threat to water quality from 

this activity. For a discussion of management practices to minimize the environmental impact of 

road salt application, see Management Measure 7: Bridges and Highways. 

0.3.6.6 Hydrocarbons 

The sources of oil, grease, and other petroleum hydrocarbons in urban areas include spillage and 

seepage of fossil fuels, discharge of domestic and industrial wastes, atmospheric deposition, and 

runoff. Atmospheric deposition is beyond the scope of this guidance (see North Carolina State 

University's Web site, http://h2osparc.wq.ncsu.edu/wetland/aqlife/atmosdep.html). 

Runoff can be contaminated by leachate from asphalt roads, wearing of tires, deposition from 

automobile exhaust, and oiling of roadsides and unpaved roadways with crankcase oil (USEPA, 

2000b). Also, many do-it-yourself auto mechanics dump used oil and other automobile-related 

fluids directly into storm drains (Klein, 1985). Petroleum hydrocarbons, such as polycyclic 

aromatic hydrocarbons (PAHs), can accumulate in aquatic organisms from contaminated water, 

sediments, and food, and are known to be toxic to aquatic life at low concentrations (USEPA, 

2000b). Hydrocarbons can persist in sediments for long periods and result in adverse impacts on 

the diversity and abundance of benthic communities. 

Hydrocarbons can be measured as total petroleum hydrocarbons (TPH), as oil and grease, or as 

individual groups of hydrocarbons, such as PAHs (see Management Measure 7). 

0.3.6.7 Heavy metals 

Heavy metals are typically found in urban runoff, with automobiles suspected to be the leading 

source (CWP, 1994). For example, Klein (1985) reported in a study of the Chesapeake Bay that 

designated urban runoff was the source for 6 percent of the cadmium, 1 percent of the chromium, 

1percent of the copper, 19 percent of the lead, and 2 percent of the zinc. 

Heavy metals are of concern because of toxic effects on aquatic life and the potential for ground 

water contamination. Copper, lead, and zinc are the most prevalent NPS pollutants found in 

urban runoff. High metal concentrations can bioaccumulate in fish and shellfish, and affect 

beneficial uses of a water body. 

0.3.6.8 Toxic pollutants 

Many different toxic compounds (priority pollutants) have been associated with urban runoff. 

The NURP studies (USEPA, 1983) indicated that at least 10 percent of urban runoff samples 

contained toxic pollutants. Methylene chloride and bis (2-ethylhexyl) phthalate were the most 

commonly reported and detected organic constituents in an ongoing evaluation of stormwater 

data from NPDES Phase 1 Municipal Separate Storm Sewer System permit holders. PAHs were 

also found in several hundred storm events (Pitt, 2004). 

0-34 
Introduction 

0.3.6.9 Temperature 

Temperature changes result from increased flows, removal of vegetative cover, and increases in 

impervious surfaces. Impervious surfaces act as heat collectors, which heat urban runoff as it 

passes over them. Data indicate that intensive urbanization can increase stream temperature by as 

much as 5 to 10oC during storms (Galli and Dubose, 1990). Elevated temperatures can be caused 

when streambeds become wider and shallower due to higher flows, removal of riparian 

vegetation along streambanks, and detaining water in runoff management facilities during warm 

weather. Elevated temperatures disrupt aquatic organisms that have finely tuned temperature 

limits, such as trout, salmon, and the aquatic insects on which they feed, by decreasing the 

amount of dissolved oxygen in the water column. Increased water temperatures can also lead to a 

shift in the algal community, disrupting the aquatic food chain (Galli, 1991). 

0.3.7 Nonpoint Source Pollutant Loading 

Nonpoint source pollution has been associated with water quality standard violations and the 

impairment of designated uses of surface waters. The National Water Quality Inventory: 2000 

Report to Congress (USEPA, 2002b) reported the following: 

Siltation, pathogens, oxygen-depleting substances, and nutrients are leading causes of water 

quality impairments in the nation's rivers and streams; and agriculture, hydromodification, 

habitat alteration, and urban runoff/storm sewers, all of which are nonpoint sources, were the 

leading sources of impairment. 

The pollutants described previously can have a variety of impacts on coastal resources. Examples 

of water bodies that have been adversely affected by nonpoint source pollution are varied. The 

Miami River and Biscayne Bay in Florida have experienced loss of habitat, loss of recreational 

and commercial fisheries, and decrease in productivity partly as the result of urban runoff 

(SFWMD, 1988). Additionally, shellfish beds in Port Susan, Puget Sound, Washington, have 

been declared unsafe for the commercial harvest of shellfish in part because of bacterial 

contamination from OWTSs (USEPA, 1991). Also, impairment due to toxic pollution from 

urban runoff continues to be a problem in the southern part of San Francisco Bay (USEPA, 

1992). Finally, nonpoint sources of pollution have been implicated in degradation of water 

quality in Westport River, Massachusetts, which discharges to Buzzards Bay. High 

concentrations of coliform bacteria have been observed after rainfall, and shellfish bed closures 

in the river have been attributed to loadings from surface runoff and OWTSs (USEPA, 1992). 

0.3.8 Other Impacts of Urban Runoff 

Other impacts not related to a specific pollutant can also occur as a result of urbanization. 

Salinity can be affected by urbanization. Freshwater inflows due to increased runoff can affect 

estuaries, especially if they occur in pulses, disrupting the natural salinity of an area. Increased 

impervious surface area and the presence of storm water conveyance systems commonly result in 

elevated peak flows in streams during and after storms. These rapid pulses or influxes of fresh 

water into saline receiving waters (i.e., bays, estuaries, and oceans) may be 2 to 10 times greater 

than normal (ABAG, 1991) This may lead to a decrease in the number of aquatic organisms 

living in the receiving waters (McLusky, 1989). 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

The alteration of natural hydrology due to urbanization and accompanying runoff diversion, 

channelization, and destruction of natural drainage systems have resulted in riparian and tidal 

wetland degradation or destruction. Deltaic wetlands have also been adversely affected by 

changes in historic sediment deposition rates and patterns. Hydromodification projects designed 

to prevent flooding can reduce sedimentation rates and decrease the marsh aggradation that 

would normally offset erosion and apparent changes in sea level within the delta (Cahoon et al., 

1983). 

0.3.9 Management Practices 

Management practices are specific actions taken to achieve, or aid in the achievement of, a 

management measure. A more familiar term might be best management practice (BMP). The 

word "best" has been dropped for the purposes of this guidance (as it was in the Coastal 

Management Measures Guidance) because the adjective is too subjective. The “best” practice in 

one area or situation might be entirely inappropriate in another area or situation. 

Four major runoff management themes dominate the management practices presented in this 

guidance document: 

− Minimize the amount of impervious land coverage and disconnect impervious areas. 

− Promote infiltration. 

− Prevent polluted runoff by not allowing pollutants and runoff to mix. 

− Remove pollutants from runoff before allowing it to flow into natural receiving waters. 

The management practices can be grouped into two basic categories: 

— Nonstructural practices. Nonstructural practices prevent or reduce urban runoff problems 

in receiving waters by reducing potential pollutants or managing runoff at the source. 

These practices can take the form of regulatory controls (e.g., codes, ordinances, 

regulations, standards, or rules) or voluntary pollution prevention practices. Nonstructural 

controls can be further subdivided: 

— Land use practices. Land use practices are aimed at reducing impacts on receiving 

waters resulting from runoff from new development by controlling or preventing 

land use in sensitive areas of the watershed. They can also be used to minimize 

total land used for development while accommodating growth. 

— Source control practices. Source control practices are aimed at preventing or 

reducing potential pollutants at their source before they come into contact with 

runoff or aquifers. Some source controls are associated with new development. 

Others are implemented after development occurs and include pollution 

prevention activities that attempt to modify aspects of human behavior, such as 

educating citizens about the proper disposal of used motor oil and application of 

lawn fertilizers and pesticides. 

— Structural practices. Structural practices are engineered to manage or alter the flow, 

velocity, duration, and other characteristics of runoff by physical means (USEPA, 1993). 

0-36 
Introduction 

In doing so they can control storm water volume and peak discharge rates and, in some 

cases, improve water quality. They can also have ancillary benefits such as reducing 

downstream erosion, providing flood control, and promoting ground water recharge. 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

0.4 Information Resources 

The Center for Watershed Protection is a non-profit organization that provides information 

concerning watershed restoration, planning, research, and training, storm water management, 

better site design, education, and outreach. Among other achievements, the Center has completed 

20 plans to protect or restore local watersheds and 30 watershed research projects, responded to 

5,000 requests for watershed advice, and trained more than 15,000 individuals through 

workshops. The Center for Watershed Protection’s Web site (http://www.cwp.org) provides links 

to upcoming workshops, current and ongoing projects, surveys, and publications. Example 

publications available electronically include Stormwater BMP Design for Cold Climates, Codes 

and Ordinances Worksheet, and Site Planning for Urban Stream Protection. The Center for 

Watershed Protection also manages the Stormwater Manager’s Resource Center Web site, which 

is designed to provide technical information to storm water managers. 

Coordinated through the European Rivers Network, Rivernet is a multilingual service providing 

information concerning river ecological projects, river basins, and organizations currently 

working on problems associated with rivers. Access to newsletters, water policy and river 

management information, educational materials, international news related to rivers, and regional 

river basin news are available at the Rivernet homepage (http://www.rivernet.org/welcome.htm). 

The Natural Resources Defense Council (NRDC), an organization with more than 500,000 

members nationwide, seeks to protect and restore the natural environment. Information relevant 

to storm water management and pollution can be accessed at their Web site 

(http://www.nrdc.org/water/pollution). An example is Stormwater Strategies, which is a 

publication intended for municipal officials, local decision-makers, citizens, and environmental 

activists that provides examples of effective storm water management programs employed across 

the U.S. Stormwater Strategies can be downloaded at 

http://www.nrdc.org/water/pollution/storm/stoinx.asp. 

The U.S. Geological Survey’s Web site offers water quality and use data; publications, products, 

and technical resources; and links to water resource-related programs. Individual USGS case 

studies and reports of grants related to urban runoff programs are available through this site, 

which is located at http://water.usgs.gov. 

Part of EPA’s Office of Wetlands, Oceans, and Watersheds, the Nonpoint Source Control Branch 

provides information on many aspects of nonpoint source pollution. Resources include 

introductory information about nonpoint source pollution, nonpoint source publications and 

information resources, funding, information on the Clean Water Act and Coastal Zone Act 

Reauthorization Amendments, and educational information. More information and access to a 

full list of available resources can be found at http://www.epa.gov/OWOW/NPS/index.html. 

EPA’s Office of Wastewater Management (OWM), in cooperation with state and local agencies, 

administers the NPDES permit program, which includes regulating storm water discharges from 

municipal separate storm sewer systems. The OWM Web site provides technical and regulatory 

information on the NPDES Storm Water program as well as publications dealing with urban 

runoff. The OWM Web site can be accessed at http://www.epa.gov/npdes and information 

specific to the Storm Water program can be accessed at http://www.epa.gov/npdes/stormwater. 

0-38 
Introduction 

The Water Environment Federation (WEF) is a nonprofit technical and educational organization 

dedicated to the preservation and enhancement of the global water environment. The Water 

Environment Federation Web site contains a search engine for periodicals, newsletters, technical 

magazines, and other publications related to wastewater treatment and water quality protection. 

Members of the organization provide technical expertise and training on issues, including 

nonpoint source pollution, hazardous waste, residuals management, and groundwater; sponsor 

conferences and other special events around the world; and review, testify, and comment on 

environmental regulations and legislation. More information on WEF is available at 

http://www.wef.org. 

The Sierra Club and American Rivers sponsored the publication of Where Rivers Are Born: The 

Scientific Imperative for Defending Small Streams and Wetlands, which provides an argument 

for protecting small, intermittent or “headwater” streams and wetlands based on the numerous 

environmental functions of these systems and their close connectivity with activities on land. The 

authors detail such functions as flood control, maintenance of water supplies, sediment trapping, 

and maintenance of biological diversity. The document can be downloaded in PDF format at 

http://iowa.sierraclub.org/Steve-Sierra%20web%20docs0526/WhereRiversAreBorn.pdf. 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

0.5 References 

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Barth, C.A. 1995. Nutrient Movement from the Lawn to the Stream? Watershed Protection 

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Booth, D., and C. Jackson. 1997. Urbanization of Aquatic Systems: Degradation Thresholds, 

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Resources Association 33(5):1077–1089. 

Booth, D., D. Montgomery, and J. Bethel. 1996. Large Woody Debris in the Urban Streams of 

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Cahoon, D.R., D.R. Clark, D.G. Chambers, and J.L. Lindsey. 1983. Managing Louisiana's 

Coastal Zone: The Ultimate Balancing Act. In Proceedings of the Water Quality and 

Wetland Management Conference. Louisiana Environmental Professionals Association, 

New Orleans, LA. 

Caraco, D., R. Claytor, P. Hinkle, H.Y. Kwon, T. Schueler, C. Swann, S. Vysotsky, and J. 

Zielinski. 1998. Rapid Watershed Planning Handbook. Center for Watershed Protection, 

Ellicott City, MD. 

Center for Watershed Protection (CWP). 1994. Cars are Leading Source of Metal Loads in 

California. Technical Note 13, Watershed Protection Techniques 1(1):28. 

City of Olympia. 1995. Impervious Surface Reduction Study: Final Report. City of Olympia 

Public Works Department, Water Resources Program, Olympia, WA. 

Couch, C. 1997. Fish Dynamics in Urban Streams Near Atlanta, Georgia. Technical Note 94. 

Watershed Protection Techniques 2(4):511–514. 

Crawford, J., and D. Lenat. 1989. Effects of Land Use on Water Quality and the Biota of Three 

Streams in the Piedmont Province of North Carolina. U.S. Geological Survey Water 

Resources Investigations Report 89-4007. U.S. Geological Survey, Raleigh, NC. 

Elder, D., G. Killam, and P. Koberstein. 1999. The Clean Water Act: An Owner’s Manual. The 

River Network, Portland, OR. 

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Federal Interagency Stream Restoration Working Group (FISRWG). 1998. Stream Corridor 

Restoration: Principles, Processes, and Practices. PB98-158348LUW. 

Galli, J. 1991. Thermal Impacts Associated with Urbanization and Stormwater Best Management 

Practices. Metropolitan Washington Council of Governments, Washington, DC, and 

Maryland Department of the Environment, Annapolis, MD. 

Galli, J., and R. Dubose. 1990. Water Temperature and Freshwater Stream Biota: An Overview. 

Maryland Department of the Environment, Sediment and Stormwater Administration, 

Baltimore, MD. 

Gregory, K., R. Davis, and P. Downs. 1992. Identification of River Channel Change Due to 

Urbanization. Applied Geography 12:299–318. 

Haile, R.W., Witte, J.S., Gold, M., Cressey, R., McGee, C., Millikan, R.C., Glasser, A., Harawa, 

N., Ervin, C., Harmon, P., Harper, J., Dermand, J., Alamillo, J., Barrett, K., Nides, M., 

and Wang, G. 1999. The health effects of swimming in ocean water contaminated by 

storm drain runoff. Epidemiology 10: 355–363. 

Hollis, F. 1975. The Effects of Urbanization on Floods of Different Recurrence Intervals. Water 

Resources Research 11:431–435. 

Horner, R.R., J.J. Skupien, E.H. Livingston, and H.E. Shaver. 1994. Fundamentals of Urban 

Runoff Management: Technical and Institutional Issues. Terrene Institute, 

Washington, DC. 

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Management. Ecological Applications 1(1):66–84. 

Klein, R.D. 1985. Effects of Urbanization on Aquatic Resources: Draft. Maryland Department of 

Natural Resources, Tidewater Administration, Annapolis, MD. 

Leopold, L.B., M.G. Wolman, and J.P. Miller. 1964. Fluvial Processes in Geomorphology. W.H. 

Freeman and Company, San Francisco, CA. 

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the Two-Year Frequency Runoff Event the Best Basis for Stream Channel Protection? In 

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pp. 144–160. 

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May, C.W., R.R. Horner, J.R. Karr, B.W. Mar, and E.B. Welch. 1997. Effects of Urbanization on 

Small Streams in the Puget Sound Lowland Ecoregion. Watershed Protection Techniques

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McLusky, D.S. 1989. The Estuarine Ecosystem. Chapman and Hall, Inc., New York, NY. 

Miltner, R.J. 2003. Fish Community Response in a Rapidly Suburbanizing Landscape. In 

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Urban Best Management Practices. Metropolitan Washington Council of Governments, 

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100–111. 

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South Florida Water Management District (SFWMD). 1988. Biscayne Bay Surface Water 

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Water, Washington, DC. 

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Discharges. U.S. Environmental Protection Agency, Office of Water, Washington, DC. 

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U.S. Environmental Protection Agency (USEPA). 2000a. 1999 National Watershed Awards 

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0-44 
Management Measure 1: Program Framework and Objectives 

MANAGEMENT MEASURE 1 

PROGRAM FRAMEWORK AND OBJECTIVES 

1.1 Management Measure 

Develop, implement, and enhance a runoff management program framework that 

— Has adequate legal authority to implement the program effectively; 

— Has an effective institutional structure; 

— Has adequate funding and staffing; 

— Incorporates comprehensive watershed planning, including watershed/subwatershed 

goals and objectives; and 

— Fosters input from citizens, stakeholders, and technical experts, and coordinates with 

other agencies. 

1.2 Management Measure Description and Selection 

1.2.1 Description 

The goal of this management measure is to ensure that urban runoff management programs are 

developed and implemented with a solid institutional foundation. Federal, state, regional, and 

local governments all play important roles in establishing and maintaining programs. 

Consequently, a team approach must be taken to avoid overlap of key responsibilities and 

authorities, and to ensure that the appropriate levels of government function cooperatively. 

1.2.1.1 Role of federal government 

Because nonpoint source runoff management programs are within the purview of state and local 

governments, the federal government’s primary role in nonpoint source runoff management 

programs is to develop broad urban runoff control guidance with participation of state, regional, 

and local governments, and to provide technical and financial assistance to support the 

implementation of effective programs and practices. 

1.2.1.2 Role of state government 

State programs play an especially important role in establishing the team approach to runoff 

management. State officials interpret and coordinate federal mandates for implementation at the 

local level, establish state performance standards, and design criteria for runoff control. States 

also typically take the lead in conducting research, providing technical assistance, developing 

public education programs, running training and certification programs for practitioners of runoff 

management, and implementing monitoring programs to help evaluate the effectiveness of 

management practices (WMI, 1997a). 

Many states allow runoff management programs to be delegated to local jurisdictions while the 

states retain important oversight and enforcement responsibilities to ensure statewide 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

consistency. States should maintain the authority to intervene if necessary. The following is a list 

of regulatory elements that might be included in a state’s runoff legislation, or in rules and 

regulations to help guide local program implementation (WMI, 1997b): 

— Criteria for local program implementation or delegation 

— Types of activities that require runoff control 

— Waivers, exemptions, and variances 

— Plan approval and inspection fees, including construction or maintenance performance 

bonds 

— Authority for a local storm water utility 

— Specific design criteria 

— Permit application and approval process 

— Operation permit requirements and time frames 

— Development and implementation of mandated educational programs related to site 

inspection of active and completed storm water management systems 

— Requirements for any other educational programs 

— Inspection requirements, including certification of inspectors 

— Maintenance requirements for postconstruction runoff control facilities 

— Penalty provisions in the event of noncompliance with requirements for the design, 

construction, or operation of storm water management systems 

1.2.1.3 Role of regional authorities 

Regional authorities often share some of the duties of state agencies but customize their services 

to fit the needs and attributes of the region. They provide a link between local communities and 

the state, and often work with state officials to establish region-based performance standards and 

design criteria for runoff controls. They also serve as a focal point for coordinating issues and 

interests among communities in the region, especially in terms of implementing the watershed 

approach, developing watershed plans, ensuring consistency of storm water runoff master 

planning, and resolving situations that affect downstream communities. 

1.2.1.4 Role of local government 

Counties and municipalities integrate local runoff management planning with land use and 

regional watershed management plans, floodplain management, wastewater planning, and other 

programs that affect the management of urban runoff. They are involved with the day-to-day 

administrative, operational, and technical aspects of runoff management and are responsible for 

performing inspections, enforcing compliance, performing operation and maintenance, 

identifying and removing illicit connections, and coordinating program funding. 

1-2 
Management Measure 1: Program Framework and Objectives 

Wisconsin DNR Revisits their Approach to Watershed Programs

The Wisconsin Department of Natural Resources (WDNR) recognized a need for a more holistic 

approach to watershed programs (Nemke, 1997). They recognized the following problems associated 

with planning, coordination, cooperation, funding, and implementation of watershed initiatives: 

— Although money is available for implementing watershed initiatives, no formal mechanisms 

exist to raise and allocate money needed to carry plans forward. 

— There is no single agency or organization that has regulatory authority over all of the 

resources that are involved in watershed initiatives, which sometimes results in conflicting 

priorities. 

— Groups that plan and implement watershed initiatives typically are made up of a diverse group 

of stakeholders with different leadership abilities, motivations and priorities, and technical 

backgrounds. This diversity makes it difficult to keep the group moving in a consistent 

direction and becomes problematic when a consensus is needed to allocate funding for 

implementation. 

— Rules and guidance documents often dictate inflexible solutions for dischargers and 

discourage more creative, innovative, or cost-effective solutions that could be equally or more 

beneficial to the watershed initiative. 

WDNR presented the following recommendations for watershed districts to help overcome logistical 

problems associated with watershed programs: 

— Staff should stay current on watershed issues and initiatives by attending conferences and 

keeping abreast of relevant journal articles and reports to get a better idea of what practices 

and policies work best. 

— Staff should take a leadership role on technical issues relating to evaluation of watershed 

problems and solutions. 

— The district should avoid taking an expanded role in solving watershed problems unless this 

role is clearly defined in their statutory authority and other government bodies agree that this 

role is appropriate and prudent. 

— The district should only commit funds to initiatives that are clearly tied to potential benefits for 

the district’s users. 

— The district should encourage and participate in evaluations of legislative initiatives that will 

provide adequate authority to implement watershed-based solutions. 

— The district should critically evaluate proposed solutions to watershed problems to ensure 

they will adequately and sensibly address these problems. 

All runoff management programs share common needs, including the legal authority to create, 

adopt, and enforce ordinances; an institutional structure designed to carry out the goals and 

objectives of the program; and adequate funding for staff and program activities. Planning serves 

as the foundation for runoff programs; it establishes management measures and determines how 

and where management practices will be applied. The program framework should also include 

the input of citizens and other stakeholders, technical experts, and other agencies in the program 

 1-3 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

planning and implementation. Communities will need to balance stakeholder concerns for the 

environment and the economy. Community groups must work together as they develop their own 

sustainable development concepts to contribute to the betterment of the environment and the 

residents of the watershed. Finally, ongoing program evaluation and feedback are critical (see 

Management Measure 12: Evaluate Program Effectiveness). 

1.2.2 Management Measure Selection 

This management measure was selected because successful runoff management programs require 

an established program framework and objectives. The measure is intended to provide general 

guidance on the common aspects of a program framework that should be considered and 

addressed when developing a runoff management program. Examples are provided to illustrate 

how the practices can be used to implement the management measure. 

1.3 Management Practices 

1.3.1 Establish Legal Authority 

A successful urban runoff program must have the legal authority to accomplish its goals and 

objectives. State-level programs derive their legal authority from various laws, codes, and 

regulations enacted by the state legislature. Only a few states have passed comprehensive 

statewide runoff management legislation. States whose laws often serve as models include 

Delaware, Florida, Maryland, New Jersey, and Washington. 

The language in state runoff legislation is usually general and might include the runoff program’s 

goals, procedures, and general requirements for maintenance. Details concerning design, 

construction, operation, and maintenance of runoff management practices are established by the 

program’s implementing regulations and guidance materials (runoff management manual). 

If authorized by state law, the state can delegate program implementation authority to local 

entities. Delegation is usually beneficial to local governments because they have a direct interest 

in seeing that practices are installed, operated, and maintained correctly. Delegation also 

provides them the flexibility to implement the program based on the needs of the community. To 

aid local communities in this endeavor and to ensure statewide consistency in runoff 

management, state program officials typically develop a state manual that presents design criteria 

and guidance for implementing specific management practices. State and local regulation writers 

typically adopt the state manual by reference into their regulations wherever appropriate to 

ensure that the information contained in the document is used and applied correctly. 

EPA’s Office of Wetlands, Oceans, and Watersheds has developed a Web site that has examples 

of model ordinances that address issues such as aquatic buffers, erosion and sediment control, 

open space development, storm water control operation and maintenance, illicit discharges, and 

postconstruction controls (USEPA, 1999b). The Web site, 

http://www.epa.gov/owow/nps/ordinance, also has materials that support particular ordinances, 

such as maintenance agreements and inspection checklists. Additionally, the Center for 

Watershed Protection’s Stormwater Manager’s Resource Center Web site has a collection of 

model ordinances, which can be accessed at http://www.stormwatercenter.net/. 

1-4 
Management Measure 1: Program Framework and Objectives 

The primary focus of the management practices discussed below is on how local governments 

can increase their ability to manage runoff by developing new ordinances or regulations, or 

modifying existing ones. It should be noted that many of these practices could also be adopted at 

the state level to ensure statewide consistency of runoff management practices. 

1.3.1.1 Examine existing laws and regulations 

The first step in crafting ordinances to improve runoff management controls at the local level is 

to examine all the existing mandates, authorities, laws, regulations, codes, ordinances, review 

processes, and so forth that pertain to environmental review in the community. By comparing 

current rules and practices with the rules needed to achieve the goals and objectives of the runoff 

management program, a community can identify gaps and weaknesses that need to be addressed. 

The resulting document, Frederick County Roundtable Recommendations: A Consensus Agreement, 

was presented to the Frederick County Commissioners in February 2000. While certainly fostering 

better site design in Frederick County, the successful Frederick County roundtable also is an important 

example for other communities interested in implementing similar projects. In addition, this project 

complements other ongoing regional, state, and local growth management efforts occurring throughout 

Maryland. 

For more information on the Frederick County Site Planning Roundtable’s recommendations, contact 

the Center for Watershed Protection, 8391 Main Street, Ellicott City, Maryland 21043; phone 410-461-

8323; fax 410-461-8324; e-mail: mailto:center@cwp.org. 

Frederick County, Maryland, Site Planning Roundtable

The Frederick County Department of Planning and Zoning and the Center for Watershed Protection 

facilitated a local site planning roundtable in Frederick County, Maryland. The roundtable worked to 

review the county’s current subdivision and zoning codes, define the local hurdles that impede the 

implementation of more innovative site planning techniques, and hammer out changes to local codes 

and ordinances that would foster more environmentally friendly development. By January 2000 the 

diverse group of planners, developers, watershed planners, and other community professionals arrived 

at a consensus on the modifications necessary to achieve widespread implementation for more 

environmentally sensitive site designs. The changes the group recommended are designed to guide 

future site development in the county toward the goals of reducing impervious cover, conserving natural 

areas, and minimizing storm water pollution. 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Revision of Development Rules for the City of High Point, North Carolina

The state of North Carolina plans to build a reservoir, called Randleman Lake, to meet the growing 

need for water in North Carolina’s Piedmont Triad region (Brewer et al., 2000). Recognizing that the 

watershed has one of the highest rates of urbanization in the region, the state has developed a set of 

rules, called the Randleman Lake Water Supply Watershed Protection Rules, to establish 

requirements for wastewater dischargers, protect and maintain riparian areas, and provide for urban 

runoff management in areas draining to Randleman Lake. The City of High Point was charged with 

developing a watershed protection ordinance to comply with the Randleman Lake Rules, which 

require strict development limitations for areas within the watershed (Table 1.1). 

Table 1.1: Summary of the Randleman Lake water supply watershed protection rules. 

Development Option 1.1.1.1.1 Description 

Critical area 

low density 

— 6% impervious surface limit or 1 dwelling unit per 2 acres. 

— 50-foot stream buffers around perennial and intermittent streams. 

Critical area 

high density 

— 30 percent impervious surface limit. 

— 100-ft and 50-ft buffers for perennial and intermittent streams, 

respectively. 

— Structural controls required for developments with 6 to 30% 

imperviousness. 

General watershed 

area—low density 

— 12% impervious surface limit or 1 dwelling unit per acre. 

— 50-foot stream buffers around perennial and intermittent streams. 

General watershed 

area—high density 

— 50% impervious surface limit. 

— 100-ft and 50-ft buffers for perennial and intermittent streams, 

respectively. 

— Structural controls required for developments with 12 to 50% 

imperviousness. 

The city undertook a two-part study to facilitate development of an ordinance that protects water 

quality while providing flexibility to accommodate projected growth. The first part of the study involved 

a committee of stakeholders charged with identifying and evaluating different strategies for watershed 

protection. The city used an iterative approach to involve the stakeholder groups with an important 

“feedback loop” and key checkpoints throughout the process to gauge and document each 

stakeholder group’s buy-in and formal approval. The second part of the study involved a comparative 

analysis of impacts of different protection strategies for the watershed. The comparative analysis 

focused on phosphorus as an indicator of water quality impacts on Randleman Lake. The analysis 

involved establishing a baseline of phosphorus loading that is not to be exceeded by alternative 

strategies for new development. It also involved identifying and estimating additional loadings from 

areas that are expected to be developed more intensely and are expected to exceed the baseline 

phosphorus loading. Strategies for offsetting these loadings elsewhere in the watershed or mitigating 

them with more protective on-site management practices were then developed and evaluated. 

The plan (see Figure 1.1) and ordinance adopted as a result of this study were based on a 

phosphorus banking principle and included the following elements: 

— Maintenance of a 6.4-square-mile critical area, which is larger and more restrictive than that 

required in the Randleman Lake Rules and yields a phosphorus loading reduction/offset of 

approximately 800 lb/yr. 

— Use of 440 lb/yr, or approximately 55 percent of the phosphorus offset, to allow increased 

imperviousness for planned higher-density nonresidential development. 

— Use of the remaining offset as a phosphorus reduction reserve. 

— Revision of ordinance(s) and engineering specifications to encourage low-impact design and 

alternatives to traditional storm water ponds. 

1-6 
Management Measure 1: Program Framework and Objectives 

Figure 1.1: Adopted watershed protection plan for the City of High Point, North 

Carolina. 

The city has adopted a watershed protection ordinance for the Deep River 1 watershed that 

incorporates the strategies listed above and has modified its engineering specifications to allow 

bioretention facilities and to provide guidance for their design. In the coming year, the city will work to: 

— Review local monitoring data and recommend additional monitoring protocols that can track 

the effectiveness of best management practices used, including new low-impact development 

design techniques. Possible funding sources for monitoring will be identified. 

— Review and revise the city’s development ordinance and engineering specifications to further 

allow and encourage low-impact design techniques. 

— Plan and host a spring 2000 low-impact development design workshop for city staff, local 

contractors, and engineers. 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

1.3.1.2 Develop or improve ordinances for water quality enhancement 

(1) Aquatic buffer ordinance. Aquatic buffers serve as natural boundaries between local 

waterways and existing development. They help protect water quality by filtering pollutants, 

sediment, and nutrients from runoff. Some other benefits of buffers are flood control, 

streambank stabilization, controlling stream temperature, and providing room for lateral 

movement of the stream channel. Good aquatic buffer ordinances specify the size and 

management of the stream buffer and are a specific planning tool to protect stream quality 

and aquatic habitat. 

Effective buffer ordinances provide guidelines for buffer creation and maintenance and 

should require: 

— Buffer boundaries that are clearly marked on local planning maps; 

— Maintenance language that restricts vegetation and soil disturbance; 

— Tables that illustrate buffer width adjustment by percent slope and type of stream; and 

— Direction on allowable uses and public education. 

(2) Erosion and sediment control ordinance. A basic goal of erosion and sediment control 

programs should be to minimize off-site impacts by first preventing erosion and then 

maximizing control of sedimentation on-site (WMI, 1997a). A key tool for accomplishing 

this goal is an effective erosion and sediment control (ESC) ordinance. 

An ESC ordinance typically requires developers to submit an ESC plan to a state or local 

regulatory agency for approval prior to initiating construction activities. This plan contains 

specific practices to prevent erosion and control sediment, as well as information concerning 

phasing of clearing and grading activities. Once the plan is approved by the regulatory 

agency, the developer and contractor are responsible for following the plan and 

implementing the management practices. If follow-up inspection reveals a lack of 

Residents’ Willingness to Pay for Riparian Buffers

In St. Charles County, Missouri, rapid growth has resulted in serious threats to the environment such 

as flooding, water pollution, and habitat loss for aquatic organisms and wildlife. To combat these 

problems, the St. Charles “Natural Watercourse Protection Ordinance” was passed, and requires 50-

foot riparian buffer along major streams and a 25-foot buffer along tributaries when adjacent land is 

being developed for residential or other non-agricultural uses. In anticipation of potential increases in 

development costs and home prices resulting from the ordinance, a study was conducted in the 

Dardenne Creek watershed to evaluate the residents’ willingness to pay for adopting buffers in newly 

developed residential communities. Survey respondents identified wildlife, environmental benefits, and 

natural appearance and sounds as the primary values of Dardenne Creek. Respondents were 

concerned about the damaging impacts of flooding, erosion, and safety of children on property values. 

43.7 percent of the respondents were willing to pay a median value of $1000 for community-owned 

and open accessible buffers. The study indicates that residents generally recognize the potential 

environmental benefits of the buffer ordinance, but outreach efforts should focus on informing 

homeowners that the ordinance may result in increased construction costs and higher home prices. 

The study’s author concludes that the residents’ willingness to pay indicates that the real estate 

market can absorb the possible increases in the construction costs due to implementing the ordinance 

(Qiu, 2003). 

1-8 
Management Measure 1: Program Framework and Objectives 

compliance, the inspector may issue a permit violation, stop-work order, or fine, or take other 

steps to compel action. 

Whether program authority is implemented at the state level or delegated to a local 

government, the ordinance should include goals, performance standards, and design criteria 

for both erosion prevention and sedimentation control. At a minimum, the ordinance should 

define the following erosion prevention design criteria: 

— The threshold for disturbed areas at which regulatory action/compliance is required; 

and 

— The maximum time frame for permanent site stabilization after final grading or 

temporary stabilization if construction ceases and the site is left dormant. 

(3) Open space ordinance. Open space development, also known as “cluster development,” is a 

planning technique that concentrates dwelling units in a compact area and leaves the balance 

of the site as natural, open space. Lot sizes, setbacks, and frontage distances are minimized, 

thereby reducing the amount of impervious cover on-site. Open space development reduces 

the need for clearing and grading by 35 to 60 percent, and increases opportunities for using 

the reserved land for a variety of purposes such as conservation, recreation, habitat preserves, 

and storm water management. Table 1.2 shows a summary of studies that contrasted 

conventional and open space designs in terms of impervious cover and storm water runoff 

(CWP, 1998a). Specific recommendations on how to limit imperviousness and maximize 

pervious areas can be found in Management Measure 4: Site Development. 

Table 1.2: Redesign analyses comparing impervious cover and storm water runoff from 

conventional and open space subdivisions (CWP, adapted 1998a). 

Impervious Cover at the Site

Residential 

Subdivisions

Conventional 

Zoning for 

Subdivision

Conventional 

Design

Open Space 

Design

Net 

Change

Percent 

Reduction in 

Runoff

Remlik Hall 5-acre lots 5.4% 3.7% -31% 20% 

Duck Crossing 3- to 5-acre lots 8.3% 5.4% -35% 23% 

Tharpe Knoll 1-acre lots 13% 7% -46% 44% 

Chapel Run 1⁄2-acre lots 29% 17% -41% 31% 

Pleasant Hill 1⁄2-acre lots 26% 11% -58% 54% 

Prairie Crossing 1⁄2- to a-acre lots 20% 18% -10% 66% 

Rapahannock a-acre lots 27% 20% -24% 25% 

Buckingham Greene c-acre lots 23% 21% -7% 8% 

Belle-Hall High density 35% 20% -43% 31% 

For open space development to be successful, the ordinance needs to be crafted to foster 

development that is both marketable and environmentally sensitive. The ordinance also needs 

to effectively address issues such as maintenance, liability, and access by emergency 

vehicles. In addition, the community needs to be prepared to manage the space or to dedicate 

open space to a responsible organization. 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

The Center for Watershed Protection and EPA Present Model Ordinances on the Web 

Communities can strengthen the language of their regulations and ordinances to better protect 

environmental resources by referring to examples of exemplary ordinances from across the country. 

The following is a list of ordinances available for download from 

http://www.epa.gov/owow/nps/ordinance. 

Aquatic Buffers 

— Language from Baltimore County, MD 

— Coastal Zone Program, RI (an example of a 

buffer ordinance in a coastal region) 

— Ordinance on Riparian Habitat Areas, Napa, 

CA 

— Portland Metro Floodplain Preservation 

Ordinance 

— Model Land Trust Agreement from the Natural 

Lands Trust 

Erosion and Sediment Control 

— Erosion and Sediment Control Ordinance 

from Minneapolis, MN 

— Clearing and Grading Ordinance from 

Olympia, WA 

— Erosion and Sediment Control Inspection 

Checklist from the Lower Platte South Natural 

Resources District, NE 

— Small Site Design Guideline from the Indiana 

Department of Natural Resources 

— Preconstruction Meeting Notice from 

Montgomery County, MD 

Open Space Development 

— Open Space Development Ordinance from 

Calvert County, MD 

— Land Preservation District Model Zoning from 

Montgomery County, PA 

— Open Space Ordinance from Hamburg 

Township, MI 

Storm Water Operation and Maintenance 

— Ordinance Language from Grand Traverse 

County, MI 

— Example Maintenance Agreement from 

Albemarle County, VA 

— Easement and Right-of-Way Agreement from 

Montgomery County, MD 

— Inspection Checklist from Anne Arundel 

County, MD 

— Performance Bond from Colorado 

Illicit Discharges 

— Fort Worth, TX, Environmental Code: Storm 

Water Protection 

— Washentaw County, MI, Regulation for 

Inspection of Residential Onsite Disposal 

Systems at Property Transfer 

— Metro. St. Louis Sewer District Sewer Use 

— City of Monterey, CA, Storm Water Ordinance

— Montgomery County, MD, Illicit Discharge 

Ordinance 

Postconstruction Controls 

— Maryland Department of the Environment 

Proposed Storm Water Management 

Regulations 

— Grand Traverse County, MI, Soil Erosion and 

Storm Water Runoff Control Ordinance 

— City of Seattle Storm Water, Grading, and 

Drainage Control Code 

— St. Johns River Water Management District, 

FL: Environmental Resource Permits 

— City of Santa Monica, CA, Municipal Code of 

Ordinances: Urban Runoff Pollution 

Source Water Protection: Ground Water 

Ordinances 

— Aquifer Protection District Ordinance from 

Stratham, NH 

— Ground Water Protection and Siting 

Ordinance from Hernando County, FL 

— Ground Water Source Protection Overlay 

District Ordinance from Salt Lake City, UT 

— Sinkhole Ordinance from Lexington, KY 

— Wellhead Protection District Ordinance from 

Weston, WI 

Source Water Protection: Surface Water 

Ordinances 

— Tahoe Regional Planning Agency Source 

Water Protection Ordinance 

— Shoreland Management Overlay District 

Ordinance from Buffalo, MN 

— Water Supply Watershed District Overlay 

Ordinance from Greensboro, NC 

— Watershed Management and Protection Area 

Overlay District Ordinance from County of 

York, VA 

— Town of Skaneateles Lake Watershed District 

Ordinance, NY 

Miscellaneous Ordinances 

— Lake Travis Nonpoint Source Ordinance 

— Storm Water Utility Ordinance from Takoma 

Park, MD 

— Transfer of Development Rights Ordinance 

from Sarasota, FL 

— Golf Course Management Guidelines from 

Baltimore County, MD 

— Wetlands and Watercourses Ordinance from 

Croton-on-Hudson, NY 

— Forest Conservation Ordinance from 

Frederick County, MD 

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Management Measure 1: Program Framework and Objectives 

(4) Storm water operation and maintenance ordinance. The expense of maintaining most storm 

water management practices is relatively small compared to the original construction cost. 

Too frequently, however, maintenance is not completed, particularly when the practice is 

privately owned. Improper maintenance decreases the efficiency of management practices 

and can also detract from the aesthetics of the practices. The operation and maintenance 

language within a storm water ordinance can ensure that designs facilitate easy maintenance 

and that regular maintenance activities are completed. 

(5) Illicit discharge ordinance. An illicit discharge is defined as any discharge to the municipal 

separate storm sewer system that is not composed entirely of storm water, except for 

discharges allowed under an National Pollutant Discharge Elimination System permit or 

waters used for firefighting operations. These non-storm water discharges occur because of 

illegal connections to the storm drain system from residential, business, or commercial 

establishments. As a result of these illicit connections, contaminated wastewater enters storm 

drains or directly enters local waters before it receives treatment at a wastewater treatment 

plant. Illicit connections might be intentional or can be unknown to the business owner; often 

they are the result of connection of floor drains to the storm sewer system. Additional sources 

of illicit discharges include improperly connected sanitary sewer lines, failing septic systems, 

illegal dumping practices, and the improper disposal of sewage from recreational activities 

like boating and camping. 

Illicit discharge detection and elimination programs are designed to prevent contamination of 

ground and surface waters by monitoring, inspection, and removal of these illegal non-storm 

water discharges. An essential element of these programs is an ordinance granting the 

authority to inspect properties suspected of releasing contaminated discharges into storm 

drain systems. Another important factor is the establishment of enforcement actions for those 

properties that are found to be in noncompliance or refuse to allow access to their facilities. 

(6) Postconstruction runoff control. The management of runoff from sites after the construction 

phase is vital to controlling the adverse effects of development on urban water quality. The 

increase in impervious surfaces such as rooftops, roads, parking lots, and sidewalks due to 

land development can have a detrimental effect on aquatic systems. High amounts of 

impervious cover have been associated with stream warming, habitat alteration, and 

decreased aquatic integrity in urban areas (Karr, 1991; May et al., 1997; Schueler, 1995; 

Shaver et al., 1994). Runoff from impervious areas can also contain a variety of pollutants 

that are detrimental to water quality, such as sediment, nutrients, road deicers, heavy metals, 

pathogenic bacteria, and petroleum hydrocarbons. 

The main goal of a runoff management ordinance for existing development is to limit surface 

runoff volumes and reduce runoff pollutant loadings. For example, the ordinance could 

specify which nonstructural and structural storm water practices are allowed in the 

community. Communities might also wish to add language pertaining to on-site runoff 

requirements, and should identify whether off-site treatment is an option. Example 

ordinances can be found on EPA’s Model Ordinances to Protect Local Resources Web site at 

http://www.epa.gov/owow/nps/ordinance/index.htm. 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

(7) Source water protection ordinances. Source water protection involves preventing the 

pollution of the ground water, lakes, rivers, and streams that serve as sources of drinking 

water for local communities. Source water protection ordinances help safeguard community 

health and reduce the risk of water supply contamination. When drafting an ordinance aimed 

at protecting these sources, drinking water supplies can be divided into two general sources: 

ground water (aquifers and wells) and surface water (lakes and reservoirs). Wellhead 

Protection Zones and Aquifer Protection Areas are two examples of source water protection 

ordinances that seek to protect ground water sources. Water Supply Watershed Districts and 

Lake Watershed Overlay Districts are examples of local management tools that provide 

protection of surface water supplies by restricting land uses around a reservoir used for 

drinking water. 

(8) Runoff management ordinances/regulations. The primary purpose of runoff regulations is to 

ensure that runoff management systems (within the area of jurisdiction) are properly 

designed, constructed, inspected, operated, and maintained. A comprehensive ordinance 

should incorporate the issues addressed below (WMI, 1997b). 

(a) Design and review requirements. Runoff management systems must be properly designed 

and constructed to function efficiently. A design manual tailored to local topographic, 

geologic, and climatic conditions and local regulations should be developed to accompany a 

runoff management ordinance. National and regional guidance is available to assist local 

governments in developing technical guidance. For example, the National Association of 

Homebuilders (NAHB, 1995) has produced a guidance manual entitled Storm Water Runoff 

and Nonpoint Source Pollution Control Guide for Builders and Developers that can be used 

to develop a technical design manual. The design manual is typically referenced in the 

ordinance to direct users to technical support for their runoff management projects. 

(b) Construction requirements. Runoff management facilities can fail prematurely if they are 

poorly constructed or if sediments and other pollutants are not carefully managed during the 

construction phase. Techniques for protecting structural practices from construction-related 

pollution are usually addressed in the state runoff management manual and incorporated by 

reference into the ordinance. Specific practices to mitigate construction site erosion and 

control sediment are discussed in Chapter 5 under the construction site erosion and sediment 

control management measure (8). 

To ensure that a facility is constructed properly, a runoff management ordinance should 

include the following: 

— Financial assurances. A guarantee, usually in the form of a surety or cash bond, 

should be made that the completed runoff management facility functions properly. 

The amount typically should not be less than 50 percent of the estimated construction 

cost of the system (WMI, 1997b). 

— Inspections. Inspectors should maintain a presence throughout the construction phase 

and conduct inspections at specified stages of construction, not at assigned time 

intervals (WMI, 1997b). 

1-12 
Management Measure 1: Program Framework and Objectives 

— As-built certifications and record drawings. Completed facilities should have official 

documentation prepared and sealed by a professional engineer or other qualified 

design professional (WMI, 1997b). 

— Allowances for damage to temporary practices. Funds should be set aside specifically 

to repair damage to erosion and sediment controls (e.g., silt fences) at temporary 

construction sites caused by severe storm flows, high winds, or fallen trees. Funds 

may be used only if documented inspections show erosion and sediment controls are 

installed and maintained as required. This allowance helps to ensure 100 percent 

compliance by contractors (Deering, 1999). 

(c) Operation and maintenance requirements. Ensuring that runoff management facilities are 

properly operated and maintained, both in the short term and the long term, is another critical 

element that should be addressed in the design phase. For the short term, the ordinance 

should stipulate a warranty period (perhaps one or two years) during which the original 

developer must retain all operation and maintenance responsibilities. The developer should 

be required to post a bond or other security to ensure that costs will be covered if any design 

defects or construction failures are discovered during the warranty period. 

Several techniques can be used to ensure longevity of management practices, including 

warranties, operating permits, and maintenance bonds. Specific requirements for operation 

and maintenance to be set forth in an ordinance might include the following: 

— An easement that provides an access road for maintenance equipment 

— Ownership of the system and maintenance access road by those who use the system 

— Inspection by a certified site inspector at defined intervals 

— Land set aside for disposal of sediments removed during maintenance 

— Clear documentation of maintenance responsibilities and maintenance schedule 

— A written maintenance agreement 

When the initial warranty period is over, long-term operation and maintenance 

responsibilities typically revert to a property owners’ association. Unfortunately, in many 

instances these types of groups do not perform important operation and maintenance tasks 

because they lack the financial, legal, and/or administrative capability. Very often, this 

neglect results in failed systems and problems for downstream property owners. The 

ordinance needs to incorporate specific elements to ensure that a system is in place for 

collecting fees, contracting for services, and establishing rules and regulations before a 

property owners’ association is granted authority for long-term maintenance. In some cases, 

it is more prudent for an alternative entity such as local government, special taxing district, or 

public utility to be responsible for long-term operation and maintenance functions. 

(d) Maintenance inspection requirements. Periodic inspections and certifications are necessary to 

ensure that the legal operation and maintenance entity is keeping the storm water system in 

good working order and making all necessary repairs. An ordinance needs to include 

language that identifies the inspectors and specifies how often the inspections are to be 

conducted. Depending on the framework, inspections could be done by the permitting 

authority or some other public agency. Alternatively, private inspectors might be used. In 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

either case, inspectors should be required to complete a state-sponsored course and receive 

certification. 

The frequency of inspection depends on the type of management practices employed at the 

site. Some types of facilities (e.g., a wet pond) might need to be inspected only annually. A 

sand filter, in contrast, might need to be inspected once a month or even more frequently 

during the wet season. The entity responsible for maintenance inspections should maintain 

inspection and maintenance records on file. In addition, procedures need to be established to 

ensure that problems identified during the inspection process are fixed in a timely manner 

and that reinspection occurs as soon as practicable. 

(9) Wetlands protection ordinance. Local governments can protect wetlands by adopting a 

wetland protection ordinance that supplements the permitting program established under 

Section 404 of the Clean Water Act (for more information on Section 404, see the 

Introduction (section 1.2.2 Regulatory Context) or 

http://www.epa.gov/owow/wetlands/facts/fact10.html). Section 404 does not cover all 

wetlands, nor does it cover all activities that may infringe on a wetland. A local regulatory 

program can be used to provide additional protection. A local ordinance should, however, be 

compatible with, supplement, and/or streamline the Section 404 program while tailoring 

wetland protection plans to meet local conditions and circumstances (Patton et al., 2000). 

Following are some of the important components of a wetlands ordinance (Cowles et al., 

1991). 

- The applicant should be required to submit a detailed wetland analysis, performed by 

a trained wetland ecologist, of the subject property, including a professional survey of 

the wetland edge. 

- A wetland should be protected by an adequate undisturbed buffer and placed within a 

permanent open space or protective easement tract to preclude future subdivision of 

the wetland. 

- Wetlands should not be used as surrogate runoff detention structures. Any runoff 

directed into a wetland should be pretreated. 

- Construction near wetland areas should utilize management practices, including 

proper placement and installation of sedimentation control and clearly marked limits 

of construction to avoid inadvertent wetland impacts. 

- Non-wetland field staff such as building inspectors, grading inspectors, or any other 

appropriate staff should be trained to recognize wetlands and to ensure management 

practices are used and enforced during the construction process.

(9) Miscellaneous ordinances. Other ordinances capture issues that are important for protection 

of water resources but do not fall into a single category. The following are examples of 

miscellaneous ordinances: 

1-14 
Management Measure 1: Program Framework and Objectives 

— The Nonpoint Source Ordinance for Lake Travis, which is located along the lower 

Colorado River near Austin, Texas, addresses techniques required to control nonpoint 

source pollution from permitted and unpermitted activities. 

— The Transfer of Development Rights Ordinance of Sarasota, Florida, allows for the 

transfer of development rights to protect environmentally sensitive areas from 

impacts caused by new development by directing new development to less-sensitive 

areas. 

1.3.1.3 Explore market-based regulatory approaches 

Water quality trading is a market-based approach to improving and preserving water quality. 

Trading allows one pollution source to meet its regulatory obligation by purchasing pollutant 

reductions created by another source that reduces pollution below levels required by federal and 

state regulations. Trading is a cost-effective solution because pollution control is achieved where 

the cost is lowest. 

EPA is currently targeting water quality trading and providing guidance and procedures. Trading 

is a possibility in all watersheds, even where water quality is not impaired, but the focus is on 

watersheds with approved TMDLs. Water quality trading is encouraged for nutrients and 

sediments. For pollutants other than nutrients or sediment, a higher level of scrutiny would be 

applied. EPA does not support the trading of persistent bioaccumlative toxic pollutants, or 

trading where water quality standards would be exceeded. 

Water quality programs should include the following provisions for trading: 

- Permits under Sections 402 and 404. 

- For NPDES permits, information on how trading baselines and conditions have been 

established and how they are consistent with water quality standards. 

- Standard methods for measuring compliance. 

- Designated uses to be protected (e.g. the antidegradation policy will be upheld).

Credible trading programs generally include:

- Legal authority and mechanisms 

- Clearly defined units of trade 

- Creation and duration of credits 

- Protocols for quantifying credits and addressing uncertainty 

- Provisions for compliance and enforcement 

- Public participation and access to information 

- Periodic program evaluations

 1-15 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

This box is intentionally left empty. 

EPA’s trading Web site (http://www.epa.gov/owow/watershed/trading.htm) provides a number 

of resources related to the current policy, new developments, case studies, and links to other 

trading programs. 

1.3.2 Develop an Institutional Structure 

The following practices follow the approach presented by the Center for Watershed Protection in 

the Rapid Watershed Planning Handbook (CWP, 1998c). This approach applies mainly to local 

efforts in small watersheds. State and regional agencies might need to conduct their efforts on a 

larger scale. Other resources that address establishing a watershed planning framework on a 

larger scales include Framework for a Watershed Management Program (Clements et al., 1996) 

and Know Your Watershed (CTIC, 2000). 

1.3.2.1 Establish a watershed baseline 

The first step in a watershed assessment process is to gather basic background information about 

the watershed and subwatersheds. This process can be used as a foundation for developing the 

rest of the watershed plan. 

(1) Define watershed and subwatershed boundaries. Watershed and subwatershed boundaries 

need to be mapped on a good topographic map such as those produced by the U.S. 

Geological Survey. These maps, an example of which is shown in Figure 1.2, can help in 

identifying the political jurisdictions and citizens that should participate in the watershed 

planning effort, and the land use patterns in the watershed and each subwatershed (CWP, 

1998c). 

(2) Identify “embedded” agricultural areas. Livestock waste management is typically not 

considered an issue in urban areas. However, the urban/suburban landscape can build up 

around an existing agricultural area, or property owners can board animals on residential 

property, making animal waste management an important component of maintaining water 

1-16 
Management Measure 1: Program Framework and Objectives 

Figure 1.2: Example of part of a subwatershed base map (Oakland Museum of 

California, No date). 

quality in urban areas. Animal wastes from stables or backyard pens contribute nutrients and 

pathogens to runoff and ground water. Manure can also be a nuisance because of odors and 

flies, and animals can contribute to the destruction of vegetation through trampling and 

overgrazing. 

Water quality problems can be associated with stables and backyard livestock pens. 

Management techniques to address these agricultural nonpoint sources include (Terrene 

Institute, 1994): 

— Siting animal areas to drain away from water bodies 

— Planting or maintaining as much vegetation as possible between animal areas and 

water bodies 

— Establishing diversions upslope from a high-use area to divert clean water away from 

bare soils and manure 

— Establishing berms or diversions downslope of high-use areas to collect contaminated 

runoff for treatment 

— Establishing fenced areas for animal use to protect vegetation 

— Collecting manure and bedding regularly and protecting stored manure from rainfall 

and runoff 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Good Horse Keeping 

Horse owners in Massachusetts and the Patriot Resource Conservation and Development (RC & D) 

Council have launched the Horse Manure Management Initiative (HMMI). The Initiative involves 

collaboration between horse owners, the Massachusetts Farm Bureau, the Massachusetts Stable 

Owners, and the Operators and Instructors Association to improve and protect water quality in Essex, 

Middlesex, Norfolk, and Suffolk counties. The HMMI is focused on education, outreach, and policy 

initiatives to promote good horse keeping practices and manure management. The Patriot RC&D 

Council plans to release a Good Horse Keeping video and a Horse Owner Directory and Resource 

Guidebook in 2003. For more information, visit http://patriotrcd.org/horse_manure_management.html. 

— Applying animal wastes as fertilizer for pastures, croplands, lawns, gardens, 

nurseries, and greenhouses at rates dictated by soil analyses 

— Composting raw manure to reduce bulk, odors, and bacteria 

Sources of information for managing pollution from livestock areas include local cooperative 

extension service offices, soil and water conservation district offices, and U.S. Department of 

Agriculture (USDA) Natural Resources Conservation Service (NRCS) offices. NRCS 

published the Agricultural Waste Management Field Handbook, which is a comprehensive 

guide for livestock operators that provides detailed technical information about practices to 

properly manage animal wastes (USDA NRCS, 1992). This document can be accessed online 

at http://www.wcc.nrcs.usda.gov/awm/awmfh.html. Additionally, EPA published National 

Management Measures to Control Nonpoint Source Pollution from Agriculture. This 

document is available for download from the Office of Wetlands, Oceans, and Watersheds’ 

Web site at http://www.epa.gov/owow. 

(3) Identify possible stakeholders. Stakeholder participation in planning for watershed 

management is crucial. Stakeholders have power and a variety of insights that will play a 

large role in whether the plan succeeds or fails. Stakeholders are affected by the outcome of 

the watershed plan, have a responsibility for implementing the plan, or have the ability to 

impede or assist the plan’s implementation. See below for a list of organizations and people 

that might be stakeholders. This group is not limited to people living or working in the 

watershed or subwatershed delineated on the watershed map. Because several local 

management units can be encompassed by a single watershed, state, tribal, interstate, and 

federal officials often are considered stakeholders in a local watershed initiative. In addition 

to identifying the stakeholders, the planning process should include developing a technical 

advisory team or committee to assist with the scientific aspects of the watershed program. 

Federal Agencies 

— Environmental Protection Agency 

— Army Corps of Engineers 

— Fish and Wildlife Service 

(Department of the Interior) 

— Federal Emergency Management 

Agency

Nonprofit Organizations 

— Greenways coalitions 

— “Friends of ...” groups 

— Watershed coalitions or foundations 

— Anglers’ groups 

— Volunteer organizations 

— Recreation/hiking groups 

1-18 
Management Measure 1: Program Framework and Objectives 

State/Local Agencies 

— Environmental or wildlife agency 

— Flood control district 

— Water rights agency (primarily in 

the southwestern United States) 

— Public works department 

— Planning/zoning department or 

board 

— State department of transportation 

— Local conservation commissions 

— Extension services from land grant 

universities 

Private Sector 

— Consulting engineers 

— Local businesses 

— Real estate companies 

— Builders/developers 

— Trade associations 

Other Citizens 

— Local residents 

— Schools/teachers 

— “Downstream” users (i.e., drinking 

water consumers) 

(4) Measure existing impervious cover. The amount of impervious cover is a key attribute of 

watersheds. The impervious cover model (CWP, 1998a) directly links imperviousness levels 

to the quality of water resources at the subwatershed scale. Crucial to the use of the model is 

an estimation of the percentage of the subwatershed covered by impervious surfaces. A 

number of practices can be used to make this estimate, ranging from measuring cover 

directly using aerial photographs to predicting cover based on the relationship between 

imperviousness and population or road density statistics. 

(5) Assemble historical monitoring data. Most water resources in urban and suburban areas have 

been monitored at one time or another. The challenge is to identify who has collected data 

and whether the data are in an accessible and usable form. Often the people that collect data 

in a particular watershed are also stakeholders or members of the technical committee. 

Whatever the source, watershed data need to be assessed in terms of quality and usefulness. 

The technical advisory team plays an important role in this endeavor. Once organized, 

historical data provide the background knowledge necessary for guiding the other steps of the 

local watershed planning process. 

(6) Assess existing mapping resources. Resource maps are used to present many aspects of the 

watershed management plan in a clear, reader-friendly format. Natural and cultural features 

that can be included on a resource map are: 

— Floodplain boundaries 

— Stream corridors 

— Soils and geologic features 

— Current and future land use 

— Transportation routes 

— Buffers 

— Wetlands 

— Detention/retention ponds 

— Direction of drainage 

 1-19 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

(7) Conduct an audit of local watershed protection capabilities. A sometimes overlooked but 

very important task associated with baseline assessment is a critical evaluation of local 

capabilities to implement watershed practices. The audit should be as complete as possible 

and should include examination of local programs, regulations, ordinances, master plans, 

staff resources, and funding. If deficiencies or potential problems are found, the audit can be 

used as a basis for making changes. 

- Water Quality Standards: The Water Quality Standards Database contains information on 

designated uses for waterbodies 

- Water Quality Inventory 305(b) Report: The National Assessment Database includes 

information on the attainment of water quality standards. Waterbodies are classified as Fully 

Supported, Threatened or Not Supporting these designated uses. 

- Total Maximum Daily Load 303(d) List: The TMDL Tracking System provides information on 

waterbodies that are designated as Not Supporting. These waterbodies are required by law to 

have TMDLs developed, and the database tracks the status of those TMDLs. 

- Water Quality Monitoring: The STORET database contains water quality, biological and 

physical data. 

- NPDES Permits: The Permit Compliance System stores data on NPDES facilities, permits, 

compliance status, and enforcement activities for up to six years. 

- Safe Drinking Water: The Safe Drinking Water Information System contains information on 

public water systems and drinking water standard violations. 

- Fish Consumption Advisories: The National Listing of Fish and Wildlife Advisories database 

includes information on fish consumption advisories issued by states, tribes, and the federal 

government. 

- Nonpoint Source Pollution: The Section 319 Grants Reporting and Tracking System is a 

compilation of information on projects and activities funded by CWA Section 319(h) funds. 

- Nutrient Criteria: The Nutrient Criteria Database stores and analyzes nutrient water quality 

data. 

- The BEACH Program: The Beaches Environmental Assessment, Closure & Health (BEACH) 

Watch database provides information on whether a specific beach is being monitored for 

water quality, the party responsible for the monitoring, the pollutants that are being monitored, 

and advisories or closures that have been issued. 

- Vessel Sewage Discharge: Vessel sewage discharge is regulated under Clean Water Act 

Section 312, which mandates the use of marine sanitation devices (on-board equipment for 

treating and discharging or storing sewage) on all commercial and recreational vessels that 

are equipped with installed toilets. Under Section 312 States may request a No-Discharge 

Zone designation that prohibits the discharge of sewage from all vessels into defined waters. 

The WATERS database can be accessed online at http://www.epa.gov/waters. 

Watershed Assessment, Tracking, and Environmental Results

EPA has developed an integrated information system for the nation's surface waters that combines 

data from various EPA Office of Water programs into one large framework. Data from the information 

system, Watershed Assessment, Tracking and Environmental Results (WATERS), is available online 

through interactive Web-based applications and mapping tools. The following is a list of programs that 

are incorporated or scheduled to be incorporated into the database: 

1-20 
Management Measure 1: Program Framework and Objectives 

1.3.2.2 Set up an institutional structure 

A successful runoff management program requires a strong institutional structure (CWP, 1998c). 

A typical institution carries out many functions, including: 

— Setting goals for the watershed and subwatersheds 

— Identifying gaps in monitoring data and taking steps to acquire needed information 

— Operating as a forum for stakeholder input 

— Reviewing and prioritizing management strategies to achieve maximum watershed 

protection 

— Establishing links with other groups and agencies 

— Encouraging cooperative exchanges of information 

— Providing funding for planning actions and exploring funding options for management 

practice implementation 

— Ensuring long-term implementation of the runoff management plan 

Key attributes needed to perform these functions are: 

— Adequate permanent staff to perform facilitation and administrative duties 

— A consistent, long-term funding source to ensure a sustainable organization 

— Inclusion of all stakeholders in planning efforts 

— A core group of dedicated people that have the support of local governmental agencies 

— Local ownership of the runoff management plan throughout the process 

— A process for monitoring and evaluating implementation strategies 

— Open communication channels to increase cooperation among organization members 

There are three types of runoff management institution models: 

— Government-directed model 

— Citizen-directed model 

— Hybrid model 

The primary difference among the three management options is the authority that is ultimately 

responsible for directing the watershed plan. In the government-directed model, local or regional 

agencies assume responsibility for making decisions about how the watershed is managed. The 

citizen-directed model is driven by citizen activists or grassroots organizations, and the hybrid 

model combines the best of both models and is recommended for most watersheds. Each 

paradigm has particular strengths and weaknesses, but whatever form the model takes, the 

framers of the institution must define its goals and carefully lay out the responsibilities and 

contributions that will be made by each element. Table 1.3 compares the typical components of 

the three models, lists advantages and disadvantages associated with each model, and specifies 

conditions where each model might best be applied. 

 1-21 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Table 1.3: Elements of three watershed management structures (CWP, 1998c). 

Element 

Government-Directed 

Model Citizen-Directed Model Hybrid Model 

Formation Created by legislative 

authority. 

Created at grassroots level by 

citizens or other interested 

parties. 

Created with some governmental 

authority and support from 

citizens. 

Membership Organization membership 

appointed by 

governmental authority. 

Stakeholder participation is 

voluntary. 

Some members are required to 

participate, but many are 

volunteers. 

Authority Structure has regulatory 

authority over land use 

and other permits. 

Advisory capacity with no 

regulatory authority over land 

use or permits. 

Some members of the structure 

have regulatory authority; others 

act in a volunteer or advisory 

capacity. 

Funding Funding is through taxes 

or levied fees. 

Funding is by grant, donations, 

or sometimes local government 

contributions. 

Much of the funding is through a 

steady source, such as an 

agreement with a local 

government, but grants might also 

compose a significant portion of 

the budget. 

Implementation Government agencies at 

the state, local, and 

federal levels implement 

the plan. 

Local governments implement 

the plan. 

Local governments implement the 

plan with some assistance from 

state and federal agencies. 

Advantages Has legal authority to 

influence development. 

Has a secure funding 

source. Consistent staff 

are available. 

Local community has ownership 

in the plan. No stakeholders are 

forced to participate. Residents 

are less intimidated by other 

citizens than by the government. 

Has some authority to implement 

the plan. Incorporates 

stakeholders from the public and 

the government. Usually has some 

stable funding source and 

permanent staff. Technical 

expertise from many sectors can 

be used to formulate the plan. 

Disadvantages Might not incorporate all 

interests. Citizens and 

local governments might 

not have a sense of 

ownership in the process. 

Might be difficult to secure a 

stable funding source. 

Implementation might be 

difficult without legal authority. 

Because most members are 

volunteers, it might be difficult 

to complete the plan quickly. 

The most vocal groups might be 

over-represented. 

Demands significant input from 

citizens and government. 

Where best 

applied 

Where the plan will 

require extensive 

regulations and land use 

rules to implement. 

Where the local 

community cannot raise 

the funds to develop and 

implement a plan. Where 

the community is not 

strongly mobilized to take 

the initiative. 

Where the local community has 

a very strong interest in the 

water resource. Where the local 

government has an excellent 

relationship with local citizens’ 

groups and developers. Where 

some external funding source, or 

a steady supply from local 

governments, can support the 

citizen groups. Where 

disagreements between different 

interests are not expected to slow 

the group’s progress. 

Most watersheds. 

1-22 
Management Measure 1: Program Framework and Objectives 

(1) Government-directed model. In this model, an agency of government takes on the 

responsibility for determining the goals of the runoff management program and directing the 

means by which those goals are met. Such a structure can consist of one agency vested with 

regulatory responsibility or a coalition of agencies from the local, state, and federal levels. 

The program framework under the government model is strong because of its legal authority 

and consistent funding, whether required by legislation or instituted as a reflection of an 

administrative priority. Government involvement ensures that the management process draws 

on broad public goals and balances the utility of various courses of action. However, 

government-directed programs often do little to raise public awareness of the need for 

resource protection, and if a government-led watershed management plan makes inadequate 

provisions for public input, feelings of disenfranchisement can result. In addition, 

interagency rivalry can hamper the effectiveness of a government-led management structure. 

The government-directed model is frequently employed when a government agency is best 

positioned to address a particular problem, or when public interest and awareness are not 

sufficient to motivate citizen participation in the runoff management process. 

(2) Citizen-directed model. This type of framework is highly legitimate in the public eye because 

it concentrates heavily on co-opting public involvement throughout the management process 

and gives the public a strong sense of ownership of the plan. Management recommendations 

coming solely from the community have no legal authority, however, and community leaders 

must rely on their ability to engage and motivate governmental entities to accomplish their 

goals. For that reason, the citizen model usually is effective only where there is a healthy 

relationship between community leaders and local government. 

(3) Hybrid model. A quasi-governmental structure, a hybrid runoff management institution is 

designed to combine legislative authority with technical advice, allowing additionally for 

stakeholder and citizen input. By representing both government and citizen interests, the 

model usually provides the most effective means of incorporating public opinion and activity 

into the needs of the locality and watershed. The specific form that a hybrid management 

structure takes depends on a variety of factors, but it will usually concentrate heavily on 

incorporating as many stakeholders as possible into the watershed planning process. Hybrid 

structures are not vested with regulatory authority but use one of several structures to 

recommend courses of action to the governing body and plan and implement runoff 

management practices. 

1.3.2.3 Determine budgetary resources available for watershed planning 

One of the most important challenges confronting a watershed manager is how to develop 

watershed and subwatershed plans within existing budget constraints. The manager needs to 

identify what sources of funding are available and develop budgets for the subwatershed and 

watershed plans. The cost of a watershed plan varies depending on choices the watershed 

manager makes regarding mapping, monitoring, modeling, and ongoing management. The 

budget also depends on the area and complexity of the watershed and its subwatersheds. 

 1-23 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

1.3.2.4 Project future land use change in the watershed/subwatershed 

Land use in a watershed and individual subwatersheds has a strong influence on aquatic 

ecosystems. Current impervious cover should have been measured as a part of the watershed 

baseline analysis. The watershed manager needs to forecast the future impervious cover based on 

available land use planning information, such as existing zoning or master plans. 

Impervious cover projection helps watershed managers determine if aquatic resources will 

degrade from current conditions (see Section 6 of the Introduction for more information about 

impervious cover). If the analysis indicates that impervious cover will increase to such an extent 

that it will cause subwatershed quality to decline, a watershed manager should consider shifting 

impervious cover to another watershed or limiting development. 

— Failing or inadequate septic systems. 

— Sewage treatment plant effluent. 

— Fertilizer application for residential and commercial landscaping. 

— Construction site sediment export. 

— Exhaust emissions. 

— Open burning. 

— Field application of manure to crops. 

They also assessed biological populations and identified priority communities and species that warrant 

special protection. 

To begin implementing a whole basin management program, the Delaware legislature established the 

Center for the Inland Bays in 1994. In 1998 the Center initiated a Tributary Strategy Program that 

organized stakeholders into three Tributary Action Teams, which assist the Center in reducing nutrient 

inputs to the bays and restoring habitat. They are also assisting DNREC in developing pollution 

control strategies to meet TMDLs for nutrients. In 1999 the Delaware House of Representatives 

passed Resolution 32, which established a multijurisdictional committee to 

— Assess progress toward implementation of the Land-Use Action Plan of the Inland Bays 

Comprehensive Conservation and Management Plan. 

— To identify areas where implementation has not been achieved. 

— To recommend changes to Sussex County’s Comprehensive Plan and implement zoning and 

subdivision ordinances. 

Finally, in 1999 the Delaware Legislature passed the Delaware Nutrient Management Law, which 

established the Delaware Nutrient Management Commission. The purpose of the Commission is to 

develop a program to address nutrient inputs from both agricultural sources and urban sources such 

as golf course landscape operations, residential inputs, and residential and commercial fertilizers. 

Southeastern Delaware Whole Basin Management 

The Delaware Department of Natural Resources and Environmental Control (DNREC) and Sussex 

County officials developed a phased process to manage the Inland Bays Basin that combines an 

assessment program with an implementation plan to solve water quality problems affecting Rehoboth, 

Indian River, and Little Assawoman Bays (Delaware DNREC, 2000). They identified excessive 

nitrogen and phosphorus as the most pressing water quality problems in the basin. They attributed the 

elevated nutrient levels to both urban and agricultural sources, including 

1-24 
Management Measure 1: Program Framework and Objectives 

Regardless of the forecasting option chosen to estimate future impervious cover, it is important 

to verify and adjust the estimate periodically. This adjustment helps ensure that land use 

planning tools for the watershed result in the desired level of impervious cover needed to 

maintain the management strategy of each subwatershed. 

1.3.2.5 Develop subwatershed plan 

Based on the information obtained in the preceding steps, the watershed manager should 

determine what goals and objectives are appropriate in the watershed and its individual 

subwatersheds. Goal-setting is among the most important steps in watershed planning, and the 

management structure should ensure full involvement from stakeholders at this stage. 

A subwatershed plan is a detailed blueprint to achieve the established subwatershed objectives. A 

typical plan may include revised zoning, management practice regulations, proposed 

management practice locations, description of proposed new programs, estimates of budget and 

staff needed to implement the plan, stream buffer widths, or monitoring protocols. 

The plan should target the subwatershed objectives with the combination of management 

practices that is most economical, effective, and feasible. Implementing management practices 

by planning on the subwatershed scale can increase cost-effectiveness and water quality benefits. 

A combination of nonstructural, on-site, regional, and channel stabilization practices specifically 

tailored to the subwatershed will help to maximize these benefits. Pollution prevention and 

nonstructural practices are key, as they can reduce the generation of pollution and its exposure to 

rainfall and runoff. In addition, implementing site-dispersed, low-impact development practices 

can help to control both runoff quality and quantity at the site level. Ensuring that drainage 

channels and floodplains are stable will provide protection against flooding and serve to buffer 

receiving waters. Finally, regional runoff control and treatment practices are a last line of defense 

to control flooding and reduce pollution. The following are descriptions of each type of practice 

and how they can meet water quality objectives in a subwatershed: 

— Nonstructural practices. Pollution prevention and nonstructural practices are effective in 

reducing the generation of pollution and its exposure to rainfall and runoff. These 

practices help to increase public awareness, and can reduce the need for pollutant 

removal capacity in runoff treatment controls and the burden of maintaining those 

controls. Used alone, however, nonstructural practices do not provide a comprehensive 

solution for runoff management. While various techniques have been developed to 

qualitatively measure the effectiveness of nonstructural practices, it is difficult to gauge 

their direct water quality benefits. 

— Site-dispersed (on-site) practices. Site-dispersed, low-impact development practices 

control runoff quality and quantity at the site level and reduce the flow volume and 

pollutant load that reaches drainage channels. In addition to these benefits, infiltration 

practices can be a source of ground water recharge and reduce the frequency of combined 

sewer overflows (CSOs). They require less land area and can provide aesthetic benefits. 

These practices can also provide cost savings from both reduced construction costs and 

lower maintenance requirements. On the other hand, responsibility might fall on the 

property owner to inspect and maintain the practices. In addition, on-site treatment 

 1-25 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

practices only treat the first 1⁄2 inch to 1 inch of runoff, and the rest is bypassed. They are, 

however, good first practices in a system of storm water management practices. 

— Regional (off-site) practices. Regional runoff control and treatment practices act as a last 

line of defense to control flooding and reduce pollution. The advantages of regional 

controls are that they are easier to maintain and do not require the actions of the property 

owner; they can provide aesthetic and recreational benefits; and they can be cost-effective 

due to the economy of scale. However, a regional pond offers no protection to upstream 

tributaries, and placement in low-lying areas may hurt natural wetlands. Communities 

may also have to address safety and liability considerations. 

— Stable drainage channels. Stable drainage channels and floodplains are important for 

protection against flooding and as buffers for receiving waters by filtering pollutants and 

preventing erosion. Riparian areas can provide aesthetic and recreational benefits as well 

as wildlife habitat. Restoring stream channels and riparian areas can, however, be 

expensive, and is not feasible when development exists along drainage channels or 

restoration conflicts with landowner use of streamside property. 

Regional vs. On-Site Development Regulations

In anticipation of dramatic growth in the next decade or two, the city of Seattle, Washington is 

considering the development of an integrated drainage plan to address storm water at the 

subwatershed level rather than on a project-by-project basis. One of the options being considered is 

the establishment of off-site mitigation programs in urban jurisdictions. These programs allow 

developers to meet on-site development requirements relating to storm water by compensating the 

municipality to provide equivalent mitigation in an off-site public facility. In a case study, Maupin and 

Wagner (2003) explore the costs and benefits of regional and onsite management practices. The 

authors determine that an offsite mitigation program might be beneficial if the municipality has storm 

water management obligations, has the authority to regulate development, requires on-site storm 

water management on new development or redevelopment projects, and cost, water quality, or 

community benefits may result from off-site treatment. Because it shifts the maintenance burden to the 

municipality, it may not be appropriate in all cases (Maupin and Wagner, 2003).

Targeting Runoff Treatment Practices for Temperature Control 

In the Token Creek Watershed in Dane County Wisconsin, a proposed 492-acre development for 

single-family homes posed concern for regulators regarding Token Creek, a cold water stream that is 

a major tributary to Lake Mendota. Managers identified three major goals for the watershed: reduce 

overall sediment and nutrient flows to Lake Mendota; protect the water quality in Token Creek, 

primarily regarding sediment and water temperature; and implement practices that will be aesthetically 

pleasing and increase property values. Managers recognized that traditional treatment practices such 

as storm water ponds and wetlands (for more information, see Management Measure 5) would not 

protect the stream from the potential thermal impacts of runoff from a highly developed area. Instead, 

the channel was lined with rock to provide infiltration, heat dissipation, and erosion control, and rockfilled gabion dams were installed. The Temperature Urban Runoff Model (TURM) was used to 

estimate water quality benefits. Modeling results predicted a 10.7 degree Fahrenheit increase in water 

temperature with the practices installed, as opposed to a predicted 21.6 degree increase without the 

practices (Dorava et al., 2003). 

1-26 
Management Measure 1: Program Framework and Objectives 

1.3.2.6 Adopt and implement the watershed plan 

The best way to ensure that a plan is implemented is to incorporate the right stakeholders, 

realistically assess budgetary resources, develop a scientifically and economically sound plan, 

and mandate the plan’s use and implementation. During and after plan development, watershed 

managers need to ensure that local governments have both the regulatory authority and the 

resources to implement the plan. 

Watershed managers need to identify funding sources to support plan implementation. One of the 

greatest costs of watershed implementation is the staff resources needed to continue monitoring 

in the watershed, design and build retrofits and new management practices, and enforce the 

ordinance and laws called for in the plan. 

1.3.2.7 Revisit and update the watershed and subwatershed plan 

A one-time watershed study only identifies the problems that exist in a watershed. Many local 

governments, for one reason or another, take on watershed planning without realizing that it is a 

process rather than a report. Watershed and subwatershed plans should continue to be updated 

and revised as the watershed management process evolves and problems are identified. 

1.3.3 Provide Adequate Funding and Staffing 

Implementing an urban runoff control program requires funding to support programs and provide 

staff. Local and state governments can provide revenue from the tax base, but environmental 

programs often come up short when they compete with other municipally funded projects. 

Alternative borrowing and fundraising techniques can be used to provide additional money for 

water quality projects. 

A variety of resources for financing information are available. The Environmental Finance 

Center, sponsored by EPA and the University of Maryland Sea Grant College, was created to 

assist local communities in finding creative ways to pay for environmental projects. The Center 

promotes alternative and innovative ways to manage the cost of environmental activities, 

provides training and development opportunities in environmental management, and works to 

increase awareness of the benefits associated with sound environmental management policies. In 

addition, the Center serves as a national repository and clearinghouse for environmental financerelated information, including information from EPA, the Environmental Financial Advisory 

Board (EFAB), and the Environmental Financing Information Network (EFIN), as well as other 

Environmental Finance Centers (EFCs) across the nation. More information about the technical 

assistance and support the Center provides, such as workshop and conference sessions, problemsolving roundtables for communities, watershed management training sessions, and utility rate 

design assistance, is provided at http://www.mdsg.umd.edu/EFC (EFC, 2000). 

Another source of financing information is the Florida Stormwater Association (FSA), which 

was formed to assist professionals in both the public and private sectors who work in the storm 

water management and finance areas. FSA provides online services to its members, including a 

newsletter, storm water utility survey, access to local ordinances, and the FSA membership 

directory. For more information about FSA, refer to http://www.florida-stormwater.org/ (FSA, 

2000). 

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— Construct lakes, detention basins, and sport fields. 

— Acquire land in key locations before development occurs. 

— Address existing problems in developed areas. 

Other sources of revenue for the program include an annual $30 per home utility charge, a new 

development charge, and existing revenue sources such as a mill levy and Johnson County storm 

water funds. 

The city’s watershed management program will be implemented by constructing new facilities, 

improving the management of existing facilities, establishing development policies and processes, and 

implementing activities to ensure compliance with new regulations associated with the Clean Water 

Act. Lenexa has recently inventoried critical natural areas in the city to provide guidance for 

conserving, protecting, and restoring natural resources. Stream restoration opportunities in developed 

areas of the city will be identified, along with measures to address flooding. Lenexa encourages 

citizens to participate in the Watershed Management Program and offers tips for improving the quality 

of urban storm water runoff. 

For more information about the Lenexa Storm Water Management Plan, contact Lenexa Public Works 

at 913-477-7680 or refer to http://www.ci.lenexa.ks.us/Stormwater/intro.html (Lenexa, No date). 

The City of Lenexa, Kansas, passed a 1/8-cent sales tax to help fund a new storm water program. The 

initiative includes the construction of multipurpose lakes and other storm water facilities to reduce 

flooding, improve water quality, and provide recreation for the citizens of Lenexa. The program differs 

from conventional storm water programs in that it also focuses on water quality and recreational 

opportunities. Most storm water programs focus only on preventing flooding. Revenue from the sales 

tax will be used to 

City of Lenexa, Kansas, Sales Tax Increase

Finally, the Center for Urban Policy and the Environment at Indiana University–Purdue 

University Indianapolis (2001) developed An Internet Guide to Financing Stormwater 

Management. This guide, located at http://stormwaterfinance.urbancenter.iupui.edu, is designed 

to help communities find ways to pay for storm water management projects. The site includes an 

annotated bibliography of existing storm water finance materials, an archive that contains 

selected previously published materials concerning storm water finance, a manual that discusses 

the financing options available to communities for storm water management programs, a set of 

case studies that describe successful finance mechanisms that have been used in seven 

communities around the country, and a group of links to other useful Web sites about storm 

water management. 

Several mechanisms that watershed managers can use to secure funding for their storm water 

programs are described below. 

1.3.3.1 Taxes and fees 

Municipalities often use taxes to fund environmental programs, but the taxes are not dedicated 

for a specific purpose and may be allocated to other, non-environmental programs. Fees are 

another method that can generate money for environmental programs. Table 1.4 outlines several 

kinds of taxes and fees that are appropriate for financing storm water management programs. 

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Management Measure 1: Program Framework and Objectives 

Table 1.4: Types of taxes and fees that can be used to raise money for storm water 

management programs (adapted from USEPA, 1994). 

Tax or Fee Description

Property and sales taxes Charged as a percentage of property value or gross sales. 

Real estate transfer taxes Assessed as a percentage of property values when property is sold. 

Commodity taxes Charged on specific items such as gasoline and hunting and fishing equipment. 

Tax surcharges Added to established tax rates. 

Tax incentives Offer tax reductions as state tax credits, deductions, or rebates. 

Tax disincentives Fees, taxes, or price increases to discourage the use of an inefficient product. 

Tax differentiation Tax charged on an inefficient product to encourage the use of an efficient substitute. 

Selective sales tax In the form of a retail tax or an inspection fee. 

Tax increment Financing incremental increases in real estate taxes to repay the original investment in 

improved public facilities that resulted in increased real estate values. 

Plan review fees Collected to conduct development plan reviews to ensure they meet requirements. 

Storm water utility fees Imposed on property owners based on amount of runoff generated, impervious area 

on the property, or the assessed value of the property. 

Impact fees The cost of infrastructure services is paid up-front by fees collected from developers 

or property owners. 

Inspection fees Collected to ensure that development plans are properly implemented. 

User fees Directly tied to the use of a resource or facility and especially useful at the local level 

where user groups are easily identified. 

Capacity credits Private interests guarantee future capacity in a public facility and provide additional 

funding to local governments for project completion. 

Effluent discharge fees Levied on an industrial facility based on the volume of pollutants discharged. Can be 

used to meet water quality objectives, to cover costs of pollution abatement, or to 

meet effluent standards. Provides economic incentive to reduce pollution output and 

is an equitable method for funding pollution control projects. 

1.3.3.2 Bonds 

Several kinds of bonds can be used to fund projects over the long or short term. Long-term bonds 

provide funding for the duration or life expectancy of the project and can be paid back all at once 

at the end of the project or little by little until the end of the project. Short-term bonds provide 

interim funding for long-term projects that have not yet been financed. There are also general 

obligation bonds, which are issued by state or local governments and are repaid using taxes and 

other revenues. Revenue bonds are also issued by state or local governments, but they are repaid 

using income or funds generated by the project itself. Finally, state revolving funds, which are 

long-term, low-interest loans to local governments or individuals for capital investments, can be 

used to fund storm water projects. Repayment allows the fund to revolve its lending ability 

continuously. The fund is intended to provide a permanent source of financing for state and local 

water quality projects and can be used for many different projects, including: 

— Construction of wastewater treatment plants 

— Implementation of approved state nonpoint source management programs and ground 

water protection strategies under section 319 of the Clean Water Act 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

— Development and implementation of estuary comprehensive conservation and 

management plans under section 320 of the Clean Water Act 

1.3.3.3 Leases 

A municipal lease grants the lessee the option of applying lease payments to the purchase of the 

facility. The lessee is responsible for paying taxes on the property. Leases can be used to finance 

the purchase of environmentally sensitive areas, land for wetland restoration, or other projects. A 

sale/lease-back arrangement allows the owner of a facility to sell it to another entity and 

subsequently lease it back from the new owner. This arrangement can provide alternative 

financing for a facility and may limit a government’s liability. 

1.3.3.4 Intergovernmental transfers and assistance 

Grants are awarded to state or local governments for assistance in meeting national 

environmental quality goals. EPA establishes the criteria that must be met before receiving 

funds, while section 319 of the Clean Water Act allocates federal funds to states for 

implementing approved nonpoint source management programs. The grant money can also be 

used for postimplementation monitoring and groundwater assessment as part of an approved 

NPS pollution control program. 

The conservation districts in Delaware have a conservation cost-share program that is funded by 

the state. Each of the three districts currently receives approximately $300,000, plus an 

additional $175,000 for nutrient management program practices. Most of the urban management 

practices involve backyard drainage projects, streambank erosion control, rehabilitation of storm 

water management ponds, urban flood control projects, tree plantings in community open space, 

conservation windbreaks, and debris pit remediation, and they can include assisting a community 

with an engineering study to determine solutions for a problem. Each conservation district 

determines the priority areas for the conservation funding, with the most urban BMPs 

implemented in New Castle County. Depending on the practice, the landowner pays 25 to 

50 percent of the costs (Mickowski, 2004). 

Using Clean Water Act Funds for Water Quality Improvements

The Delaware Department of Natural Resources and Environmental Control (DNREC) is using the 

Clean Water State Revolving Fund to effect water quality improvements. Practices implemented with 

the funds include wastewater collection to eliminate 300 failing onsite wastewater treatment systems 

and prevent 594 new systems; replacement of failing onsite wastewater treatment systems; sediment 

and storm water management practices; water body restoration practices such as stream bank 

stabilization, wetland restoration, and riparian buffer installations; land purchases and conservation 

easements for water quality protection; and implementation of Comprehensive Conservation and 

Management Plans for the Delaware Estuary and Delaware Inland Bays. For more information on the 

Clean Water State Revolving Fund, see http://www.epa.gov/owmitnet/cwfinance/cwsrf. 

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Management Measure 1: Program Framework and Objectives 

1.3.3.5 Public-private partnerships 

The private sector can invest in public-sector facilities. This approach reduces the financial 

burden for the public sector through cost sharing and is especially appropriate when neither the 

public nor private entities can fund the projects themselves. However, there might be political 

opposition from government workers or negative public opinion due to private ownership and 

operation of a public facility, even though private operations are often more cost-efficient, 

provide a higher level of service, and require less implementation time than public operations. 

1.3.4 Foster Input from Technical Experts, Citizens, and Stakeholders 

Most runoff management institutions require input from three groups of people—technical 

experts, citizens, and stakeholders—to plan and implement successful runoff management 

practices. Technical committees are often set up to provide expertise on scientific issues, while 

citizen advisory and stakeholder committees afford the public a chance to include their opinions 

in the management process. 

1.3.4.1 Technical committees 

The central principle of technical committees is that proactive involvement of all stakeholders 

will result in greater watershed improvements because actions will have the approval of all 

interests. Ideally, members of the technical committee are also agency representatives in the 

larger management institution. Members may include representatives from the state and county 

natural resources, environment, planning, health, and water resources management entities. In 

addition, federal agency representatives and individual citizens with expertise in scientific fields 

or engineering may participate. The technical committee evaluates monitoring data and identifies 

data gaps, coordinates monitoring efforts within the watershed to obtain missing data, evaluates 

proposed regulatory or land use changes with respect to their potential impact on the watershed 

resource, interprets scientific data for the watershed management institution, and assesses and 

coordinates currently approved implementation projects. 

1.3.4.2 Citizen committees 

A citizen committee is open to all citizens and provides direct feedback to the management 

institution on public sentiments regarding the planning process. The review of citizen concerns in 

a comprehensive process is critical in gaining community support. Some of the possible 

functions of a citizen committee include organizing public outreach and community awareness 

projects, such as tree planting days, stream cleanups, storm drain system stenciling, watershed 

awareness days, and volunteer activities, and exploring funding sources and grant-writing. In 

addition, such a committee might organize media relations and publicity programs such as press 

releases, informational flyers, and watershed awareness campaigns; act as a liaison between 

citizen groups and government agencies; and establish early stakeholder and public involvement. 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Creating Quality Places was a coordinated effort between multiple stakeholders. In the first phase, a 

steering committee and three advisory committees were convened by MARC to ensure broad 

stakeholder representation. The steering committee, which included elected officials, developers, civic 

leaders, citizens, planners, and representatives of other stakeholder groups, provided input and 

direction throughout the proceedings. The three advisory committees provided specific and technical 

input during deliberations. These committees each represented a specific sector of the development 

arena and included mayors, city council members, county commissioners, planning commissioners, 

city managers, planning directors, park professionals, public works professionals, developers, 

builders, architects, and engineers. 

The initial quality principles were developed by merging the principles devised by each of the four 

committees. At a joint session of the four committees, the combined principles were reviewed, 

strengths and weaknesses of each were identified, and the principles were edited. The edited 

principles were then reviewed through a questionnaire, which was administered at public forums 

conducted for each topic area. The steering committee and advisory committees conducted a final 

review, and the quality principles were finalized. This development and review process allowed 

stakeholders to be involved throughout the entire process. 

MARC also ensured stakeholder involvement by organizing public forums to establish dialogue on 

quality development issues and to raise awareness about land use and development practices. The 

forums consisted of two parts. The first part was a session at which national speakers and local 

panels discussed issues, and the second was a workshop that provided steering and advisory 

committee members with an opportunity to ask questions and discuss concerns. 

For more information about the quality principles, including specifics of the final 20 quality principles, 

resources for implementing the principles, and case studies of how other communities are using the 

principles, refer to www.qualityplaces.marc.org (MARC, 2000). 

Creating Quality Places Program, Kansas City, Missouri

The “Creating Quality Places: Successful Communities by Design” is a program of the Mid-America 

Regional Council (MARC), which represents city and county governments in the bistate Kansas City 

metropolitan area. The program, which is partially supported with resources from EPA’s Sustainable 

Communities Challenge Grant Program, is aimed at developing a better quality of life in 

neighborhoods throughout the Kansas City region. Creating Quality Places is divided into two phases. 

In the first phase, 20 quality principles were identified to guide future development. These principles 

offer the best means for the region to grow, while also preserving and enhancing the quality of life 

enjoyed by residents. The second phase of the program focuses on the means for implementing these 

principles. 

1.3.4.3 Stakeholder committees 

Stakeholder committees address the goals and opinions of the agencies, organizations, or 

individuals directly affected by management activities in the watershed. The incorporation of 

stakeholder views into the development of the watershed plan is crucial to building consensus 

and gaining support for future implementation. Typical stakeholders involved in the watershed 

planning process include: 

— Conservation groups (e.g., Trout Unlimited, Save our Streams, Bass Masters) 

— Developers 

— Homeowners 

— Citizen associations 

1-32 
Management Measure 1: Program Framework and Objectives 

— Farmers 

— Industrial and commercial business interests 

— Utility companies 

Other groups, such as trade associations, research and academic institutions, sporting groups, and 

individual citizens, might also wish to be involved in the process. When planning occurs at the 

watershed level or higher, local and regional offices of federal agencies will also often decide to 

become involved. By placing the emphasis for watershed management on the subwatershed 

level, the number of stakeholders guiding plan development will be much more manageable. 

Early and frequent involvement of stakeholders is a key ingredient in building support for the 

subwatershed management process. Stakeholders should be given a meaningful and well-defined 

role in the formulation of management plans. Sharing data and mapping, establishing goals, 

setting priorities, developing management criteria, measuring success, and reviewing and 

approving subwatershed plans will strengthen stakeholder ownership in the plan. 

1.3.5 Establish Intergovernmental Coordination 

The watershed management institution’s primary responsibility is to oversee the execution of a 

watershed management plan. The management institution focuses the diverse stakeholders in a 

watershed into a viable group capable of guiding implementation. The institution is also 

responsible for the timely preparation and implementation of the watershed plan and its revision 

as project goals are achieved or changed. Communities might elect to create a single authority 

for an entire watershed, or a series of smaller authorities at the subwatershed level. The 

effectiveness of the management institution is dependent upon its ability to forge all interagency 

or multi-jurisdictional partnerships and agreements necessary to support the organization over 

the life of the planning process. 

Intergovernmental coordination is essential when establishing a watershed management program, 

especially when the watershed extends over more than one political jurisdiction. Without the 

participation of a broad spectrum of local, state, and federal agencies, most watershed planning 

endeavors will not have the financial or information-gathering resources required to continue 

beyond initial start-up efforts. Interagency coordination requires sharing of resources and data, 

joint development and endorsement of a watershed management plan, and continued 

participation of all agencies. Care must be taken to avoid interagency rivalries or 

miscommunication. 

The first step in fostering interagency coordination is the establishment of a watershed 

management institution. One instrument that has been used to steer this process is the 

Memorandum of Understanding (MOU). An MOU is an agreement by government agencies and 

local stakeholder representatives to work together in the creation of a watershed planning 

strategy. MOUs are widely used because agencies can enter into these agreements while 

retaining their jurisdictional and budgetary appropriation authority. MOUs are not legally 

binding contracts. Instead, the points in an MOU are presented in a broad manner to facilitate 

consensus. Typically short (one or two pages), these agreements outline the goals and objectives 

for the watershed management institution. The basic contents of an MOU are: 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

— Identification of the parties involved in the process 

— Vision statement 

— Purpose of the MOU (issues to be addressed by the agreement) 

— Pact to provide assistance to the partnership for coordination of planning efforts under a 

central management organization 

— Resolution to use the watershed plan as guidance in future land use or water management 

decisions 

— Signatures of all partners involved 

Philadelphia’s Office of Watersheds

In 1998, the Office of Watersheds was created within the Philadelphia Office of Water. The new 

department is charged with administering a watershed management program that integrates 

combined sewer overflow, storm water management, and drinking water source protection. The 

watershed approach focuses on regional and local partnerships and supports watershed initiatives at 

the local level through innovations and demonstrations, and by facilitating cooperation between 

stakeholders. The Office of Water’s "watershed technology center" is a central repository of technical 

support such as Geographic Information Systems, information technology, and model development for 

the various watershed programs. The office is working with local watershed organizations, academic 

institutions, and other agencies to pursue funding for demonstration projects, streambank restorations, 

and information collection for regional watersheds (Neukrug, 2003; WERF, 2000). 

1.3.6 Develop Training and Education Programs and Materials 

Training programs and educational materials designed for people directly involved in the design 

and implementation of a runoff management program are essential. Most states and many local 

governments have developed guidance manuals, workshops, and other educational opportunities 

to assist developers, site designers, contractors, plan reviewers, consultants, inspectors, and 

others in understanding and complying with runoff management goals and objectives. 

Most states make education and training voluntary. A few states, however, including Delaware, 

Florida, Maryland, South Carolina, and Virginia, have made professional educational programs 

mandatory by law or regulation. Delaware, for example, requires that “all responsible personnel 

involved in a construction project will have a certificate of attendance at a Department-sponsored 

or approved training course for the control of sediment and storm water before initiation of land 

disturbing activity.” The state provides personnel training and educational opportunities for 

contractors to meet this requirement, and has delegated program elements to conservation 

districts, counties, and other agencies. 

In addition to professional audiences, the public can greatly benefit from runoff management 

education and training. Public awareness of program goals leads to greater support. Awareness 

can be achieved in many ways, including workshops, brochures, meetings, and media 

campaigns, as well as hands-on projects like storm drain stenciling and stream clean-ups. 

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Management Measure 1: Program Framework and Objectives 

Watershed citizens can and do play an important role in controlling nonpoint source pollution. 

Consequently, they need to acknowledge and be educated on pollution prevention issues and 

activities. Management practices concerning this topic are discussed in greater detail under the 

Management Measure 9: Pollution Prevention. 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

1.4 Information Resources 

An Internet Guide to Financing Stormwater Management is a Web site presented by the Center 

for Urban Policy and the Environment (2001) at Indiana University-Purdue University 

Indianapolis. The site includes an annotated bibliography of existing storm water finance 

materials, an archive that contains selected previously published materials concerning storm 

water finance, a manual that discusses the financing options available to communities for storm 

water management programs, a set of case studies that describe successful finance mechanisms 

that have been used in seven communities around the country, and a group of links to other 

useful Web sites about storm water management. The site can be accessed at 

http://stormwaterfinance.urbancenter.iupui.edu. 

The Center for Watershed Protection’s Rapid Watershed Planning Handbook (CWP, 1998) 

describes techniques communities can use to more effectively protect and restore water 

resources. This document is available for purchase from the Center for Watershed Protection’s 

Web site (http://www.cwp.org). 

Framework for a Watershed Management Program (Clements, 1996) develops a specific 

watershed management protocol to increase the understanding of the critical components in 

watershed management programs. The publication is available for purchase from the Water 

Environment Research Foundation by calling 800-666-0206 and specifying publication order 

number D53016. 

Building Local Partnerships, an Internet brochure published by the Conservation Technology 

Information Center (no date), provides an overview of local partnerships, including the types of 

partnerships that can be made, a how-to guide for forming partnerships, and caveats, as well as 

links to other resources pertaining to partnership-building. The publication can be accessed at 

http://www.ctic.purdue.edu/KYW/Brochures/BuildingLocal.html. 

The Environmental Finance Center (2000) was created to assist local communities in finding 

creative ways to pay for environmental projects. The Center promotes alternative and innovative 

ways to manage the cost of environmental activities, provides training and development 

opportunities in environmental management, and works to increase the public and private 

sector's awareness of the benefits associated with sound environmental management policies. 

The site includes Creative Financing Techniques for Establishing Riparian Forest Buffers (or 

other land protection efforts), which describes methods such as notification, recognition, and 

nonbinding agreement programs; management agreements and leases; financing arrangements, 

such as agreements tied to loans; easements; and land acquisition to encourage conservation and 

stewardship of ecologically significant properties. The site also includes Financing Stream 

Corridor Protection with a Community Quilt, which describes a method for financing 

environmental protection and restoration efforts using a “community quilt” of financing 

techniques that has the potential to cover the variety of activities within the watershed. The 

Environmental Finance Center is located at http://www.mdsg.umd.edu/EFC. 

The Florida Stormwater Association (2000) Web site contains information for storm water 

managers and stakeholders, including a manual entitled Establishing a Stormwater Utility in 

1-36 
Management Measure 1: Program Framework and Objectives 

Florida, storm water utility surveys, articles, news, and activities, and links to storm water 

management resources. The site can be accessed at http://www.florida-stormwater.org/. 

The National Association of Counties (1999) has assembled a comprehensive kit that provides 

counties a host of tools for beginning and strengthening programs that favor purchase of products 

that are energy-efficient, contain recycled materials, and are less hazardous to the environment 

and human health. The kit includes case studies, a model purchasing resolution, a sample press 

release, and a comprehensive list of resources. It can be ordered (free for members, $10 for 

nonmembers) from the National Association of Counties’ Web site at 

http://www.naco.org/Template.cfm?Section=Publications&Template=/cffiles/pubs/publications.

cfm&PubCat=EPP. 

The State and Local Government Guide to Environmental Program Funding Alternatives

(USEPA, 1994) provides an overview of traditional (nongovernmental) funding mechanisms and 

innovative approaches for funding environmental programs. The document can be downloaded 

from http://www.epa.gov/owow/nps/MMGI/funding.html. 

The Catalog of Federal Funding Sources for Watershed Protection (USEPA, 1999a) provides a 

guide for watershed practitioners on federal funds that might be available to support a variety of 

watershed protection projects. The catalog presents information on 69 federal funding sources 

(grants and loans) that can be used to fund watershed projects. The information on funding 

sources is organized into categories including coastal waters, conservation, economic 

development, education and research, environmental justice, forestry, Indian tribes, mining, 

pollution prevention, and wetlands. The catalog also includes key words that can be used to 

search for funding programs for particular subject areas. The document is available in HTML 

format at http://www.epa.gov/owow/watershed/wacademy/fund.html. 

Model Ordinances to Protect Local Resources (USEPA, 1999b), located at 

http://www.epa.gov/owow/nps/ordinance, is a Web site of model ordinances that can serve as a 

template for those charged with making decisions concerning growth and environmental 

protection. For each model ordinance listed, there are several real-life examples of ordinances 

used by local and state governments around the nation. The ordinances address matters that are 

often forgotten in many local codes, including aquatic buffers, erosion and sediment control, 

open space development, storm water control operation and maintenance, illicit discharges, and 

postconstruction controls. There is also a miscellaneous category containing ordinances that 

don't fit into these sections. In addition, this Web site has materials that support particular 

ordinances, such as maintenance agreements and inspection checklists. 

EPA's Office of Wastewater Management (USEPA, 2001) has a financing Web site 

(http://www.epa.gov/OWM/finan.htm) that provides an overview of the many types of assistance 

they provide to national, state, and local programs to abate and prevent municipal water 

pollution. Included is guidance information such as Paying For Water Quality: Managing 

Funding Programs to Achieve the Greatest Environmental Benefit and Guide to Using EPA's 

Automated Clearing House For the Drinking Water State Revolving Fund Program as well as 

information on programs such as the Clean Water State Revolving Fund (SRF), Construction 

Grants Programs, Section 106 Water Pollution Control Program Grants, Section 104(b)(3) Water 

Quality Cooperative Agreements, and Indian Set-Aside Grants. 

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The Watershed Management Institute, Inc. (1997a) printed a book entitled Institutional Aspects 

of Urban Runoff Management: A Guide for Program Development and Implementation. This 

book presents a comprehensive review of the institutional frameworks of successful urban runoff 

management programs. It was developed to assist individuals responsible for developing and 

implementing urban erosion, sediment control, and storm water management programs. The 

book is available for purchase ($10 for Storm Water Phase II communities, $27 for others) using 

an order form that can be downloaded at http://www.naco.org/Template.cfm?Section= 

Publications&Template=/cffiles/pubs/publications.cfm&PubCat=EPP. 

The Southeast Michigan Council of Governments (SEMCOG) is a regional planning partnership 

that supports local planning efforts through technical support, the facilitation of 

intergovernmental coordination, and the adoption of region-wide plans and policies. SEMCOG 

partnered with six local communities to assemble a workbook, Opportunities for Water Resource 

Protection in Local Plans, Ordinances, and Programs: A Workbook for Local Governments, 

which provides guidance on planning to protect water resources. SEMCOG’s approach is not 

prescriptive, but rather provides various options for planners, outlining key programmatic and 

regulatory components for a range of watershed protection approaches. The workbook 

emphasizes the need to address the protection of water resources through planning and 

prevention, and is meant to serve as a basis for local governments to customize their individual 

plans based on the needs and resources of the community. The book is available for download at 

http://www.stormwater.ucf.edu/publications/urban_runoff.pdf. 

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Management Measure 1: Program Framework and Objectives 

1.5 References 

Brewer, K., J. Butcher, M. Clar, T. Clements, J. Doll, K. Marquis, and E. Thirolle. 2000. City of 

High Point (NC) Deep River 1 Watershed Assessment and Stormwater Plan. Prepared by 

Tetra Tech, Inc., for the City of High Point, NC. 

Center for Urban Policy and the Environment. 2001. An Internet Guide to Financing Stormwater 

Management. http://stormwaterfinance.urbancenter.iupui.edu/home.htm. Last updated 

April 2, 2001. Accessed November 29, 2001. 

Center for Watershed Protection (CWP). 1998a. Better Site Design: A Handbook for Changing 

Development Rules in Your Community. Center for Watershed Protection, Ellicott 

City, MD. 

Center for Watershed Protection (CWP). 1998b. Nutrient Loading from Conventional and 

Innovative Site Development. Prepared for Chesapeake Research Consortium. Center for 

Watershed Protection, Ellicott City, MD. 

Center for Watershed Protection (CWP). 1998c. Rapid Watershed Planning Handbook. Center 

for Watershed Protection, Ellicott City, MD. 

City of Lenexa. No date. Turning Rain into Recreation: Lenexa’s New Approach to Storm Water 

Management. http://www.ci.lenexa.ks.us/Stormwater/index.html. Accessed March 19, 

2001. 

Clements, T., C. Creager, A. Neach, M. Marcus, and T. Schueler. 1996. Framework for A 

Watershed Management Program. Final Report. Project 93-IRM-4. Water Environment 

Research Foundation, Alexandria, VA. 

Conservation Technology Information Center (CTIC). 2000. Know Your Watershed Home Page. 

http://www.ctic.purdue.edu/KYW. Last updated April 19, 2000. Accessed April 24, 

2000. 

Conservation Technology Information Center (CTIC). No date. Building Local Partnerships: A 

Guide to Watershed Partnerships. 

http://www.ctic.purdue.edu/KYW/Brochures/BuildingLocal.html. Accessed April 23, 

2002. 

Cowles, C.D., D. Sheldon, and S. Dietz. 1991. Guidance on Developing Local Wetlands 

Projects: A Case Study of Three Counties and Guidelines for Others. Submitted to the 

Office of Wetlands Protection, United States Environmental Protection Agency, by the 

New England Interstate Water Pollution Control Commission. 

http://www.epa.gov/OWOW/wetlands/initiative/local.html. Last updated January 17, 

2003. Accessed August 13, 2003. 

Deering, J.W. 1999. Moving the Earth for Environmental and Financial Success. John W. 

Deering, Inc., Bethel, CT. 

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Delaware Department of Natural Resources and Environmental Control (DNREC). 1997. 

Conservation Design for Stormwater Management. Delaware Department of Natural 

Resources and Environmental Conservation, Dover, DE. 

Delaware Department of Natural Resources and Environmental Control (DNREC). 2000. Whole 

Basin Management: Inland Bays Environmental Profile. Document number 40-

01/00/03/14. Delaware Department of Natural Resources and Environmental Control, 

Dover, DE. 

Dorava, J.M., A.R. Espinosa, K. Johnson, and D. Severson. 2003. Enhancing Storm Water 

Infiltration to Reduce Water Temperature Downstream. In Proceedings, National 

Conference on Urban Storm Water: Enhancing Programs at the Local Level, February 

17–20, 2003, Chicago, IL. 

Dreher, D.W., and T.H. Price. 1994. Reducing the Impacts of Urban Runoff: The Advantages of 

Alternative Site Design Approaches. Northeastern Illinois Planning Commission, 

Chicago, IL. 

Environmental Finance Center (EFC). 2000. The Environmental Finance Center. 

http://www.mdsg.umd.edu/EFC. Last updated January 2000. Accessed January 25, 2001. 

Florida Stormwater Association (FSA). 2000. The Florida Stormwater Association. 

http://www.florida-stormwater.org/. Accessed September 29, 2005. 

Illinois-American Water Company. No Date. Project Description: Alton Water Treatment 

Facility, Water Treatment Residuals Handling Via Suspended Solids Trading. 

Description submitted as a comment to USEPA during public comment period for this 

document. 

Karr, J.R. 1991. Biological integrity: A long-neglected aspect of water resources management. 

Ecological Applications 1(1): 66–84. 

Maupin, M., and T. Wagner. 2003. Regional Facility vs. On-site Development Regulations: 

Increasing Flexibility and Effectiveness in Development Regulation Implementation. In 

Proceedings, National Conference on Urban Storm Water: Enhancing Programs at the 

Local Level, February 17–20, 2003, Chicago, IL. 

Maurer, G. 1996. A Better Way to Grow: For More Livable Communities and a Healthier 

Chesapeake Bay. Chesapeake Bay Foundation, Annapolis, MD. 

May, C.W., R.R. Horner, J.R. Karr, B.W. Mar, and E.B. Welch. 1997. Effects of urbanization on 

small streams in the Puget Sound Lowland ecoregion. Watershed Protection Techniques

2(4):483–494. 

Mickowski, R. 2004. Posting to NPSInfo Listserve, RE: Urban BMP Cost Share Programs, 

October 18, 2004. 

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Management Measure 1: Program Framework and Objectives 

Mid-American Regional Council (MARC). 2000. Creating Quality Places: Successful 

Communities by Design. Mid-American Regional Council, Kansas City, MO. 

National Association of Counties. 1999. Local Government Environmental Purchasing Starter 

Kit: A Guide to Greening Government through Powerful Purchasing Decisions. National 

Association of Counties, Washington, DC.

National Association of Homebuilders (NAHB). 1995. Storm Water Runoff and Nonpoint Source 

Pollution Control Guide for Builders and Developers. National Association of 

Homebuilders, Washington, DC. 

Nemke, J. 1997. August 8. Recommendations for Watershed Planning and Activities. Memo 

from Jim Nemke to Commissioners from the Metropolitan Madison Sewerage District, 

Madison, WI. 

Neukrug, H.M. 2003. Watersheds and EPA Program Integration. Presented at USEPA National 

Water Directors Meeting, January 22, 2003. 

Oakland Museum of California. No date. Guide to San Francisco Bay Area Creeks: Arroyo Viejo 

Watershed Map. http://www.museumca.org/creeks/1220-OMAViejo.html. Accessed 

April 5, 2002. 

Patton, C.J., A.H.Windrope, S.S. Beamish, E.C. Shute, Jr., R.B. Hooper, R.S. Taylor, and B.A. 

Schmidt. 2000. Protecting Local Wetlands: A Toolbox for Your Community. Save The 

Bay and Shute, Mihaly & Weinberger, LLP. 

http://www.savesfbay.org/atf/cf/%7B2D306CC1-EF35-48CC-B523-

32B03A970AE5%7D/ProtectingWetlands.pdf. Accessed August 13, 2003. 

Qiu, Z. 2003. Residents’ Willingness to Pay for Adopting Riparian Buffers for Newly Developed 

Residential Communities. Presented at the American Water Resources Association 2003 

International Congress on Watershed Management for Water Supply Systems. June 29–

July 2, 2003, Millenium Hotel, New York, NY. 

Schueler, T. 1995. Site Planning for Urban Stream Protection. Metropolitan Washington 

Council of Governments, Washington, DC. 

Shaver, E., J. Maxted, G. Curtis, and D. Carter. 1994. Watershed Protection Using an Integrated 

Approach. In Stormwater NPDES Related Monitoring Needs, proceedings of an 

Engineering Foundation Conference held in Mount Crested Butte, Colorado, August 7–

12, 1994. 

South Carolina Coastal Conservation League (SCCCL). 1995. Getting a Rein on Runoff: How 

Sprawl and Traditional Town Compare. SCCCL Land Development Bulletin, no. 7. South 

Carolina Coastal Conservation League, Charleston, SC. 

Terrene Institute. 1993. Clean Water in Your Watershed: A Citizen’s Guide to Watershed 

Protection. Terrene Institute, Alexandria, VA. 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Terrene Institute. 1994. Pollution Control for Horse Stables and Backyard Livestock. Prepared 

for U.S. Environmental Protection Agency, Region 6, Dallas, TX, by Terrene Institute, 

Washington, DC. 

U.S. Department of Agriculture, Natural Resources Conservation Service (USDA NRCS). 1992. 

Agricultural Waste Management Field Handbook. U.S. Department of Agriculture, 

Natural Resources Conservation Service, Washington, DC. 

U.S. Environmental Protection Agency (USEPA). 1994. A State and Local Government Guide to 

Environmental Program Funding Alternatives. EPA 841-K-94-001. U.S. Environmental 

Protection Agency, Office of Water, Washington, DC. 

U.S. Environmental Protection Agency (USEPA). 1999a. Catalog of Federal Funding Sources 

for Watershed Protection. 2nd ed. EPA 841-B-99-003. U.S. Environmental Protection 

Agency, Washington, DC. 

U.S. Environmental Protection Agency (USEPA). 1999b. Model Ordinances to Protect Local 

Resources. http://www.epa.gov/owow/nps/ordinance/index.htm. Accessed March 25, 

2001. Last updated October 29, 1999. 

U.S. Environmental Protection Agency (USEPA). 2001. Office of Wastewater Management 

Financial Assistance. http://www.epa.gov/OWM/finan.htm. Last updated March 22, 

2001. Accessed March 30, 2001. 

Water Environment Research Foundation (WERF). 2000. Creation of a Philadelphia Office of 

Watersheds. Progress Newsletter 11(1). 

http://www.werf.org/press/Winter00/philadelphia.cfm. Accessed July 29, 2003. 

Watershed Management Institute (WMI). 1997a. Institutional Aspects of Urban Runoff 

Management: A Guide for Program Development and Implementation. Watershed 

Management Institute, Inc., Ingleside, MD. 

Watershed Management Institute (WMI). 1997b. Operation, Maintenance, and Management of 

Stormwater Management. Watershed Management Institute, Inc., Ingleside, MD. 

1-42 
Management Measure 2: Watershed Assessment 

MANAGEMENT MEASURE 2 

WATERSHED ASSESSMENT 

2.1 Management Measure 

Develop and implement a watershed assessment program to: 

— Characterize watershed conditions 

— Establish a set of watershed indicators 

2.2 Management Measure Description and Selection 

2.2.1 Description 

Watershed assessment and monitoring are tools used to characterize water quality and to identify 

trends in water quality over time (USEPA, 1998c). This management measure describes 

methods that can be used to determine the health of water bodies by using watershed indicators 

that measure physical, chemical, and biological conditions. 

2.2.2 Management Measure Selection 

2.2.2.1 Overview 

Watershed assessment is a critical component of a watershed-based approach to managing 

receiving waters. Watershed assessment is needed to develop both protection and restoration 

strategies, identify priorities, and adjust management prescriptions based on trend analyses. 

Both rapid and extensive assessments can be performed to determine water body status and 

trends. Numerous metrics, such as EPA’s Rapid Bioassessment Protocols for Use in Wadeable 

Streams and Rivers: Periphyton, Benthic Macroinvertebrates, and Fish; Lake and Reservoir 

Bioassessment and Biocriteria; and Estuarine and Coastal Marine Waters:Bioassessment and 

Biocriteria Guidance, are available for determining water body status. In general, the objectives, 

available funding, and expertise of the assessors will determine the level of assessment 

conducted. 

An assessment and monitoring program is important for effective watershed management 

because it provides a basis for decisions and actions, and allows managers to continually reassess 

progress and redefine goals and priorities. Monitoring enables water quality managers to 

identify existing or emerging problems. Monitoring also facilitates responses to emergencies 

such as spills and floods, and helps water quality managers target specific pollution prevention or 

remediation programs to address these problems. Assessment and monitoring can be used to 

determine whether program goals, such as compliance with pollution regulations and 

implementation of effective pollution control actions, are being met. Monitoring programs 

should be established based on indicators of human health and aquatic life. A large number of 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

documents and case studies are available to use as resources (see Information Resources at the 

end of this chapter). 

2.2.2.2 Examples of monitoring and assessment programs and methodologies 

State pollution control agencies, Indian tribes, local governments, and federal agencies typically 

are responsible for watershed assessment and monitoring activities. These entities monitor water 

quality and identify waters and watersheds that do not meet clean water goals through various 

programs, which include the following: 

— Unified Watershed Assessments (UWAs), developed by states in 1999 to assess the 

health of watersheds and identify watersheds in need of restoration (i.e., watersheds that 

do not currently meet clean water and other natural resource goals). UWAs also identified 

watersheds that need preventive action to sustain water quality using ongoing state, tribal, 

and federal programs, as well as pristine or sensitive watersheds on federal lands that 

need an extra measure of protection. The results of these assessments can be obtained 

from state environmental protection departments. 

— Water Quality Reporting Program, established under CWA section 305(b), which 

mandates the collection of water quality information and reporting on the condition of 

waters every two years. 

— 303(d) program, established under CWA section 303(d), which mandates the use of 

monitoring and other water quality information to develop lists of waters that do not meet 

water quality standards. 

— Nonpoint Source Program, established under CWA section 319, which involves 

identifying waterbodies that are impaired by nonpoint sources. 

— Source Water Protection Program, established under the Safe Drinking Water Act, which 

involves assessments of drinking water sources that form a basis for actions to protect 

such sources. 

— State Revolving Fund (SRF) Program, which involves developing and prioritizing clean 

water projects. 

— Federal Emergency Management Agency’s National Flood Insurance Program, which 

involves conducting floodplain studies and developing mitigation plans. 

— Marine pollution control programs, which include identification of coastal water quality 

problem areas as part of efforts to reduce polluted runoff to coastal waters. 

— Wetlands Program, which involves developing assessments of wetland areas that need 

special attention or protection. 

One example of a state assessment program comes from the Commonwealth of Pennsylvania. 

The state’s Act 167 requires that watershed assessments consider the following objectives 

(Pennsylvania DEP, 1999): 

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Management Measure 2: Watershed Assessment 

— Implement nonpoint source pollutant removal methodologies 

— Maintain ground water recharge 

— Reduce channel erosion 

— Manage overbank flood events 

— Manage extreme flood events 

The state established four subtasks to achieve these objectives: 

— Determine the water quality design storm 

— Determine the runoff capture design storm (recharge/retention) 

— Establish streambank erosion requirements 

— Establish overbank/extreme event requirements (release rates) 

To accomplish these subtasks, Pennsylvania developed a process that will ultimately lead to the 

development of standards for stream bank erosion, infiltration, water quality, overbank flooding, 

and extreme storm events. The assessment fits into a larger framework for integrated watershed 

resource management, which includes the following steps: 

— Watershed assessment/prioritization 

— Watershed evaluation 

— Restoration/protection plan development 

— Financial resources secured 

— Restoration/protection plan implementation 

— Results compared to goals

2.3 Management Practices 

2.3.1 Characterize Watershed Conditions 

2.3.1.1 Establish a reference condition 

It is important to establish a reference that characterizes the relatively unimpaired condition of 

the water body. The reference condition establishes a basis for making comparisons between 

sites, and is essential for detecting impairment. Conversely, if a water body is found to be 

impaired, it is important to have an understanding of natural background concentrations before 

undergoing costly efforts to mitigate anthropogenic inputs. 

There are two types of reference conditions—site-specific and regional. Site-specific reference 

conditions are determined from one or more sites in a watershed or stream from a point where 

discharges (nonpoint source, point source, or a combination) are occurring. Regional reference 

conditions typically are established from a population of relatively unimpaired sites within a 

relatively homogeneous region and habitat type. An ecoregional framework based on land 

surface form, soil, potential natural vegetation, and land use has been developed by Omerink 

(1987) to interpret spatial patterns in data (USEPA, 1999); these ecoregions can be used to help 

develop a reference condition for a relatively homogeneous region. Regional reference 

conditions are often preferable to site-specific conditions because they are more widely 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

applicable, they produce a larger sample of unimpaired sites, and they allow more robust 

statistical comparisons. 

The U.S. Geological Survey (USGS) developed a model for determining ecoregional background 

concentrations of nitrogen and phosphorus as a function of annual runoff, basin size, atmospheric 

nitrogen deposition rate, and region-specific factors. Background total nitrogen (TN) 

concentrations ranged from 0.02 mg/L in the western United States to more than 0.5 mg/L in the 

southeastern United States. Background total phosphorus concentrations ranged from less than 

0.0006 mg/L in the western United States to more than 0.08 mg/L in the Great Plains (Smith et 

al., 2003). 

2.3.1.2 Model pollutant sources and loads 

Watershed managers can use models to estimate storm water pollutant loads in receiving 

waterbodies. Modeling of pollutant loadings can help watershed managers target specific areas 

for nonpoint source control. More specifically, runoff models can accomplish one or more of the 

following: 

— Simulate the generation and movement of water and pollutants from their point of origin 

to a place of treatment or disposal into receiving waters 

— Perform frequency analyses on water quality parameters to determine the return periods 

of concentrations or loads 

— Provide input for an analysis of receiving water quality 

— Determine the relative effects of pollution control options 

— Determine optimal locations and combinations of management practices 

— Provide input to cost-benefit analyses 

Selecting the model that is most appropriate to fulfill watershed management goals requires 

careful consideration of trade-offs with respect to level of detail, data requirements, cost, and 

accuracy. For example, a high level of detail requires a more complex model. Data 

requirements are also important: a complex model might require more data than one has or is 

willing to collect. Sometimes published data can be substituted for field-collected data. The 

advantage of using published data is avoidance of costly, labor-intensive fieldwork. A major 

data source is the USEPA National Urban Runoff Program (NURP) database, which contains 

concentration values measured for 30 cities (USEPA, 1983). Information generally required for 

models includes the following: 

Quantity Parameters

— Rainfall information 

— Catchment area 

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Management Measure 2: Watershed Assessment 

— Imperviousness 

— Runoff coefficient 

Quality Parameters

— Constant concentrations (event mean concentrations or EMCs) 

— Constituent median and coefficient of variation (CV) 

— Regression relationships 

— Buildup and wash-off parameters 

Calibration/Verification Parameters

— Measured rainfall 

— Measured runoff 

— Water quality samples 

While model calibration is beneficial, models generally used for watershed assessments do not 

strictly require calibration and precision to determine compliance with permit requirements or 

Clean Water Act requirements. Therefore, these models can be simpler and less expensive, 

while still providing watershed managers with information on pollutant loadings and sources. 

Another consideration when choosing a model is its reputation. Watershed managers should 

become familiar with the model’s concepts, assumptions, and limitations, as well as the 

experiences of other users. In choosing the most appropriate model, watershed managers should: 

— Use the simplest model that will satisfy the project’s objectives 

— Use a model that is consistent with available data 

— Predict only the water quality parameters of interest 

— Make predictions over the broadest time scale that will satisfy the objectives 

— Become familiar with the characteristics and assumptions of the model 

Using pollutant loading models has advantages and disadvantages. Measured data are preferable 

to simulated data, especially when characterizing the magnitude of a pollution problem, because 

accurate concentration values are important. Models cannot substitute for good field-sampling 

programs, but they can be used to extrapolate and to augment field-sampling results. 

To ensure quality results from a modeling effort, sensitivity analyses should be performed when 

uncertainty exists regarding data quality or model assumptions. Also, if possible, models should 

be calibrated and validated using measured values (field monitoring). This process is laborintensive and can add to the expense of the modeling effort, but it is worthwhile to ensure 

accuracy when making management decisions. 

A detailed description of water quality models of all types can be found in the Compendium of 

Tools for Watershed Assessment and TMDL Development (USEPA, 1997a). In general, 

watershed managers can choose from several different methodologies depending on the specific 

goals of the modeling effort, including the following: 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

— Constant concentration or published yield values. This method involves calculating 

loads as the product of the proportion of land area in a particular land use and the 

published loading rates for that land use. A disadvantage is that the catchments from 

which the published values are derived may not represent the catchment of interest. 

However, the calculations are very simple and easy to use for general loading 

assessments. Options include coupling constant concentrations with a hydrologic model 

so that loading will vary with flow, or calculating a confidence interval for loading to 

determine the level of uncertainty that can be tolerated before conclusions change. This 

method might be robust enough to answer straightforward management questions despite 

assumptions. 

— Unit loads. This method involves calculation of the mass of the pollutant of interest per 

area of watershed per unit of time. It is site-specific (demographic and hydrologic factors 

are important determinants) and is based on average runoff volume (not coupled to a 

hydrologic model). Also, loading rates are variable and difficult to extrapolate from one 

area to another. This is a relatively simple method that does not require a great deal of 

data collection. Published values can be used at the expense of some accuracy. 

— Simple empirical model. This method uses spreadsheet calculations to combine 

precipitation data with a runoff coefficient and land use-specific constant concentrations. 

This method easily simulates a mixture of land uses, allowing the study area to extend 

over a large area without compromising the quality of results. The model can quantify 

relative contributions from different land uses, and can be expanded readily to 

incorporate more complex calculations. The hydrologic modeling is very simple, 

however, and the model does not necessarily work well for short-term predictions. Also, 

using published constant concentrations in the model introduces errors; locally measured 

concentrations would greatly improve the model’s performance. 

— Statistical method. The statistical method uses a derived, usually lognormal frequency 

distribution of estimated mean concentrations (EMCs) of pollutants. This method is 

useful for assessing the frequency of exceedance of water quality standards, but it has 

weak hydrologic assumptions. The model can be coupled with stream flow, storage, and 

treatment data to improve accuracy and estimate the effects of management practices on 

water quality. Estimates can be improved by using measured EMC values rather than 

published ones. EMCs can vary widely because of seasonal and watershed land use 

variations, and might require at least one year and often two years of field verification to 

be statistically significant. 

— Regression equations. Regression equations are published equations from the U.S. 

Geological Survey (USGS) (Driver and Tasker, 1990) that relate loads and EMCs to 

catchment, demographic, and hydrologic characteristics. They usually incorporate total 

storm loads and runoff flows or volumes. They require neither preliminary estimates of 

EMCs nor local monitoring data, and standard errors are provided for a measure of 

uncertainty. They are more or less accurate depending on the pollutant of interest and the 

level of precipitation (arid vs. humid). The equations predict only the mean rather than a 

frequency distribution of EMCs or loads, and they are subject to error when extrapolating 

to conditions that are different from those used to derive the equations. A related 

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Management Measure 2: Watershed Assessment 

approach uses rating curves to relate pollutant loads or EMCs to flow rates or volumes, 

thereby allowing quantification of intra-storm variations in these measures. 

— Buildup and washoff. This method is used to determine loadings by estimating the 

buildup of pollutants during dry weather and estimating washoff during rainfall events. 

This method quantifies intra-storm variations in pollutant loading and is good for 

comparing the relative effects of management practices. However, processes of sediment 

transport and erosion that are fundamental to this method are still poorly understood. 

Moreover, this method requires averaging the extent of pollutant buildup on 

heterogeneous urban surfaces. This averaging can result in erroneous predictions because 

actual values vary widely over relatively small areas. Assumptions include linear buildup 

and generic washoff coefficients that might or might not represent actual conditions. 

Estimates can be improved by using local monitoring data such as site-specific buildup 

and washoff estimates for model calibration. 

— Mechanistic models. Mechanistic models contain hydrologic and water quality 

components and use mathematical algorithms to represent the mechanisms that generate 

and transport runoff and contaminants. They are the most comprehensive models in that 

they incorporate many variables to produce the best estimations of the numerous 

mechanisms that affect pollutant loading. However, they require substantial local data to 

set and verify parameters, and they demand both skill and commitment from staff. Users 

must ensure that the models are documented, supported, and proven through the 

experience of other users. There are several commercially available mechanistic models, 

including STORM by the U.S. Army Corps of Engineers and SWMM and HSPF by EPA. 

(See Web references and resources below.) 

The confounding factors for load estimation models are: 

— Inputs from atmospheric deposition (H2SO4, NO3, etc.) 

— Ground water inputs 

— Pervious surfaces that confound runoff estimates 

— Sediment transport and erosion 

— Pollutants adsorbed to solids. These pollutants, namely metals and organics, can be 

estimated as a proportion of the total suspended solids concentration or annual load. 

— Point sources in the watershed (e.g., industrial and commercial sources and publicly 

owned treatment works) 

All of these factors can be included in the surface runoff model at the expense of time and 

simplicity and can improve the accuracy of loading estimates. Before they are included, 

consideration should be given to the level of detail needed for the analysis. 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

— Keep track of hundreds of candidate management practice sites. 

— Develop management scenarios using different combinations of management practices. 

— Evaluate the practices’ impact on water quality. 

— Compare scenario results. 

— Present the information to a wide range of people. 

LORELEI provides decision support through data management, scenario development and evaluation, 

and enhanced involvement in and understanding of the watershed management process. LORELEI 

stores data about potential management practice locations and associated costs, practice types, and 

effectiveness data, as well as standard geographic information such as natural features, watershed 

delineations, and property ownership. Through scenario development, the program allows for rapid 

selection of individual projects and entire categories of management practices to build various 

scenarios. LORELEI then evaluates the scenarios to estimate and compare their costs and benefits. 

Finally, with enhanced involvement and understanding, LORELEI uses GIS to give decision makers 

an opportunity to participate directly in the watershed management process and to clearly understand 

issues, components, and cost and benefit implications of different management scenarios. GIS 

linkages allow for fine-tuning of the scenarios to determine the cost and performance effects of 

different suggestions made by participants at public meetings. 

Application of a GIS Decision Support Tool to Urban Watershed Management in Fulton County, 

Georgia 

The high density of development in Sandy Springs, a suburban area northwest of Atlanta, reduces the 

opportunities for new, areawide management practices such as regional detention ponds. Instead, 

multiple on-site or local management practices are recommended. In response to the need for 

developing storm water and water quality plans, a GIS application called LORELEI was developed 

(Slawecki et al., no date). LORELEI allows users to rapidly develop and compare watershed 

management alternatives for catchments with hundreds of management practices. It was developed 

to 

2.3.1.3 Model receiving water quality 

Receiving water quality models identify impacts from runoff inputs and help watershed 

managers determine whether receiving waters meet water quality standards. Usually, computer 

models are used because of the complexity of calculations. Models are available for streams, 

lakes, reservoirs, estuaries, bays, and coastal segments. Most models couple quantity 

(hydrodynamic) and quality parameters, but some consider these parameters separately. 

A useful water resource impact model is the Long-Term Hydrologic Impact Assessment 

(L-THIA), which was developed by Purdue University (2000) for land use planners to provide 

site-specific estimates of changes in runoff, recharge, and nonpoint source pollution resulting 

from past or proposed land use changes. The model uses regional climate data and user-provided 

location, land use, and soil group data for up to three different scenarios (past, present, and 

future). The results are in the form of tables, bar charts, and pie charts. The model is available at 

http://danpatch.ecn.purdue.edu/~sprawl/LTHIA7. 

The best sources of information for receiving water quality models are either government 

agencies or product vendors. The following is a list of government agencies that can provide the 

information needed to choose the most appropriate model: 

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Management Measure 2: Watershed Assessment 

— USEPA Center for Exposure Assessment Modeling, Athens, Georgia 

— US Army Corps of Engineers, Waterways Experiment Station, Vicksburg, Mississippi 

— US Army Corps of Engineers, Hydrologic Engineering Center, Davis, California 

— USGS, Reston, Virginia 

— National Oceanic and Atmospheric Administration (NOAA), Silver Spring, Maryland—

estuaries and bays 

— Tennessee Valley Authority (TVA), Knoxville, Tennessee—rivers and reservoirs 

Additional guidance regarding load estimation and receiving water quality modeling is provided 

in Compendium of Tools for Watershed Assessment and TMDL Development (USEPA, 1997a), 

which supports the watershed approach by summarizing available techniques and models that 

assess and predict physical, chemical, and biological conditions in water bodies. This document 

is intended to provide watershed managers and other users with information helpful for selecting 

models appropriate to their needs and resources. The Compendium includes information on the 

following: 

— A wide range of watershed-scale loading models 

— Field-scale loading models 

— Receiving water models, including eutrophication/water quality models, toxics models, 

and hydrodynamic models 

— Integrated modeling systems that, for example, link watershed-scale loading with 

receiving water processes 

— Ecological techniques and models that can be used to assess and/or predict the status of 

habitat, single species, or biological communities 

An additional modeling resource is Modeling of Nonpoint Source Water Quality in Urban and 

Non-Urban Areas, which is a major nonpoint source model review effort published by EPA in 

1991. It focuses on nonpoint source assessment procedures and modeling techniques for both 

urban and non-urban land areas (Donigian and Huber, 1991). The report provides detailed 

reviews of specific methodologies and models, as well as overview discussions and model 

comparison tables. Simple procedures, such as regression and loading function approaches, are 

also described in the report, along with complex models like SWMM, HSPF, STORM, 

CREAMS/GLEAMS, SWRRB, AGNPS, and others. Brief case studies of modeling efforts are 

summarized, with emphasis on the use of nonpoint and comprehensive watershed models for 

watershed management activities. This publication can be found at 

http://yosemite.epa.gov/water/owrccatalog.nsf/0/b28aec046488178585256fc700700b24?OpenD

ocument. 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

EPA has assembled a Web site with information about and links to water quality models. This 

site includes basic information, EPA-supported models, other federal government-supported 

models, technical guidance for models, and model training and meetings. The Web site can be 

accessed at http://www.epa.gov/waterscience/wqm/. 

2.3.2 Assess Cumulative Effects 

A watershed assessment should include an evaluation of cumulative effects, which are combined 

effects of multiple activities over space or time. Such effects can be difficult to assess because a 

large number of resources can be affected and often there are multiple pathways through which 

these effects can occur. In addition, the appropriate spatial and temporal scales for the analysis 

usually are uncertain. Because many environmental assessments do not take cumulative effects 

into account, most likely because there is no explicit process for analyzing them, MacDonald 

(2000) developed a conceptual process to guide their assessment and management. The process 

is divided into three phases: the scoping phase, the analysis phase, and the implementation and 

management phase. Within each phase are a group of interrelated steps that, if followed, 

typically lead to a complete analysis of the cumulative effects on a watershed. The three phases 

and their steps are shown in Figure 2.1. 

2.3.3 Estimate the Effectiveness of Treatment Programs 

A useful tool to estimate the effectiveness of treatment practices on water quality is the 

Watershed Treatment Model (WTM), which was developed by the Center for Watershed 

Protection (Caraco, 2001). The WTM is a simple model for rapidly assessing how various 

management programs influence pollutant loadings and/or habitat quality in urban watersheds. It 

incorporates many simplifying assumptions that allow watershed managers to assess various 

programs and sources that are not typically tracked in more complex models. The WTM consists 

of two basic components: pollutant sources and treatment options. The pollutant sources 

component estimates the load from a watershed without treatment measures in place. It assesses 

two broad categories of pollutant sources: primary land uses and secondary sources. The 

treatment options component estimates the reduction in the uncontrolled load resulting from a 

wide range of treatment measures. Treatment options are broadly defined in the model as storm 

water treatment practices and storm water management programs. The most current version of 

the WTM, version 3.0, can track sediment, nutrients, and bacteria. The WTM can be a useful 

tool for managers who are analyzing the effectiveness of current watershed restoration programs, 

preparing Total Maximum Daily Loads (TMDLs), or evaluating the watershed benefit of 

National Pollutant Discharge Elimination System (NPDES) storm water programs. For more 

information about the WTM, contact the Center by e-mailing center@cwp.org or visit their Web 

site at http://www.cwp.org. 

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Management Measure 2: Watershed Assessment 

 2-11 

Define the spatial scale of the assessment

Identify the relative magnitude of risk to

each resource

Select the appropriate level of effort for

the assessment

Identify issues and resources of primary

concern, including their location

Identify key cause-and-effect mechanisms

Estimate the range of natural variability

and relative condition for the resource(s)

of concern

Identify past, present, and expected future

activities

Evaluate the relative impact of past,

present, and expected future activities

Define the time scale of the assessment

Evaluate the validity and sensitivity of

the predicted cumulative effects

Identify possibilities for modification,

mitigation, planning, and restoration

Scoping

Phase

Analysis

Phase

Management

Phase

Identify key data gaps and monitoring

needs

Modify resource and

location(s) of concern

Modify spatial or

temporal scale

Figure 2.1: Conceptual process for assessing cumulative effects (MacDonald, 2000). 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

— Socioeconomic: inventory of public education efforts, such as number of publications produced 

and distributed, Web site hits, media campaigns, stream cleanup activities

— Programmatic: the following are programmatic indicators: 

— Number of approved erosion and sediment control plans and disturbed acreage 

— Number of inspections and enforcement actions for erosion and sediment controls

— Number of citizen calls about flooding and drainage problems, and number of responses

— Cost and number of flooding and drainage projects

— Investigative and corrective actions for illicit discharge detection and elimination

— Operation and maintenance activities

— Number of approved site and subdivision plans, and acreage served

— Number and type of BMPs installed, the number of acres served by each BMP, and 

installation and maintenance information

Under the Phase II Storm Water Rule, communities are required to go beyond chemical pollutant 

monitoring to track the implementation of storm water management programs. This database can 

serve as a useful tool in fulfilling this requirement and can be used as a model for the development of 

varied indicators of program success (Hillegass, 2003). 

— Physical and hydrological: acres of open space land protected from development 

— Water quality: pollutant loadings for nutrients 

The Hampton Roads Planning District Commission in Chesapeake, Virginia, has developed a 

database to track and evaluate various indicators of the effectiveness of the storm water program. The 

indicators fall into four basic categories: water quality, physical & hydrological, socioeconomic, and 

programmatic. This database tracks the indicators as listed below (Hillegass, 2003): 

Indicators of Storm Water Program Effectiveness

2.3.4 Establish a Set of Watershed Indicators 

Watershed indicators are monitoring parameters or techniques used to measure the effectiveness 

of management practices in meeting watershed and subwatershed goals and objectives. 

Indicators range from complex chemical or toxicity testing methods to simple public perception 

surveys. Watershed managers can choose one or more of these indicators to better focus their 

monitoring efforts. Regardless of the parameters or technique, to be effective, an indicator must 

accomplish the following: 

— Reflect a measurable attribute of a watershed goal or subwatershed management 

objective 

— Be measured using scientifically valid protocols, quality controls, and assessment 

techniques to ensure that results are replicable, consistent, compatible with other data 

collection efforts, and statistically valid 

— Be measured at one or more locations that will adequately characterize “typical” 

conditions in the management unit and establish reference conditions against which 

future data comparisons can be made 

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Management Measure 2: Watershed Assessment 

— Be monitored over a long enough period to establish observable trends 

— Be compatible with available finances, personnel, and other resources. The cost of 

implementing the watershed indicator is an important consideration. 

The Center for Watershed Protection and EPA published a reference to help municipalities select 

a suite of indicators that will most effectively measure conditions in their watershed (Claytor and 

Brown, 1996). This publication, Environmental Indicators to Assess Stormwater Control 

Programs and Practices, presents profiles with information such as advantages, disadvantages, 

cost, and applicability for 26 indicators, which include water quality, physical/hydrological, 

biological, social, programmatic, and site indicators. The document is available online at 

http://www.cwp.org. 

2.3.5 Establish Water Quality Indicators 

Conduct water quality monitoring. This type of monitoring involves measuring pollutants in 

both runoff and baseflow conditions. The most commonly measured constituents are oxygen 

demand, nutrients, metals, pH, temperature, flow or discharge, solids (e.g., total suspended solids 

or turbidity), fecal coliform, and a measure of oil and hydrocarbons (e.g., total petroleum 

hydrocarbons [TPH] or polycyclic aromatic hydrocarbons [PAHs]). Measurements can be taken 

at management facilities or in receiving waters. This method allows for the identification of 

trends in water quality over time and can identify areas that are degraded relative to low-impact 

reference sites. Changes in water quality that result from changes in land use or from the 

implementation of management practices can be detected to prioritize future conservation or 

restoration efforts. The specific constituents found in receiving waters can aid in identifying the 

source of the pollution problem and help target management practices effectively. The 

methodology for water quality monitoring is well-outlined in specific protocols, and results are 

quantitative and easy to present and compare to other monitoring databases. However, the 

monitoring effort must be long-term because of the high variability in constituent concentrations, 

and it might be expensive because of labor requirements or equipment costs for automation. 

Volunteer monitoring programs can reduce some of the expense of monitoring while providing 

the additional benefit of educating the public. EPA’s Volunteer Monitoring Web site has more 

information about volunteer monitoring (http://www.epa.gov/owow/monitoring/volunteer). 

(1) Conduct toxicity testing. These methods, often called whole effluent toxicity (WET) tests, 

involve exposing standardized freshwater, marine, and estuarine vertebrates, invertebrates, 

and plants to water samples to directly measure the adverse effects of effluents. Both acute 

and short-term chronic effects can be assessed. The test organisms can be either resident 

species or species that will be restocked or reintroduced. Toxicity reduction evaluation 

(TRE) can be used to identify the agent of toxicity, which helps to identify the pollutant 

source and indicates which management practices would be appropriate to treat the problem. 

Although this method allows managers to distinguish among a range of conditions and 

chemicals, species’ responses vary substantially with respect to the choice of species, 

location (laboratory or in situ), and duration of the test. Also, chronic toxic effects, which 

may take a long time to manifest, are not measured with this type of testing. The TRE 

process can be expensive and is often used to specifically identify pollutants when receiving 

waters have previously been identified as impaired through other, less-expensive methods. 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

More information on WET methods is available at http://www.epa.gov/OST/WET. 

Descriptions and guidance on other analytical methods are provided at 

http://www.epa.gov/ost/methods (USEPA, 2000d). 

(2) Measure the frequency at which water quality standards are exceeded. This method is 

usually based on chemical standards and can be derived from existing data or as part of the 

biennial 305(b) reporting process. It can identify long-term trends in water quality, storm 

water impacts, and the effectiveness of management practices. However, because the ability 

to detect exceedances is highly dependent on the frequency and timing of sample collection, 

brief periods of exceedance might be missed (during storm flow) and long-term conditions 

inaccurately represented. Also, exceedance frequencies provide little information about 

causes and sources of pollution. Costs associated with this method are minimal because data 

are usually collected through other programs. Guidance and information on EPA and state 

water quality standards and criteria can be found at http://www.epa.gov/ost/standards

(USEPA, 2001c). 

(3) Determine sediment pollutant levels. This type of monitoring involves the determination of 

pollutant load carried by sediments and deposited in slow-moving receiving waters. Analysis 

is usually conducted using spectrophotometry and chromatographic tests of samples from 

natural or artificial water bodies. The extent of toxicity in sediments can be determined by 

comparing sample results to reference samples that are known to be relatively unimpacted. 

Measured pollutant levels can also be compared to existing standards for typical 

contaminants in sediment (USEPA, 2000d). Using sediment contamination as an indicator of 

water quality is often confounded by uncertainty related to levels of concern and long-term 

impacts, the inability to identify pollutant sources, and lag time between discharge and 

settling. However, long-term trends in sediment pollutant loading can be detected if 

monitoring is conducted over a long period. 

(4) Measure microbial contamination. This type of monitoring involves measuring 

concentrations of microbes such as fecal coliform or Escherichia coli to ascertain the 

probable presence of pathogens in the water column. These pathogens result in the closure of 

beaches, fishing areas, and shellfish beds. Tracking the frequency of such closures may 

indicate contamination in effluent from industrial or municipal facilities or septic systems, or 

runoff from agricultural areas. In areas where no treatment facilities or septic systems are 

present, runoff can be identified as the main source of pathogens. Measuring microbe 

concentrations can help determine the effectiveness of management practices in removing 

this type of contamination from receiving waters. 

Trends in beach or shellfish closures over time may indicate a developing problem if high 

concentrations or counts become more frequent, or they may demonstrate the effectiveness of 

management efforts if decreasing trends occur. However, many of the bacteria measured 

have a variety of nonhuman sources, making it difficult to identify the source of the 

pollution. In addition, they are short-lived in the water column, so depending on when 

samples are collected, the occurrence of high bacterial concentrations may not be detected 

even though they are present at certain times (e.g., during storm flows). 

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Management Measure 2: Watershed Assessment 

Bacterial source tracking refers to a family of methods that can be used to distinguish among 

sources of fecal contamination and can aid in tracking illicit discharges to storm sewer 

systems. Bacterial source tracking requires development of a database of known sources 

against which samples can be compared (Zhang et al., 2003). The methods can be molecular 

(e.g. DNA fingerprinting, or more specifically, ribotyping, pulsed-field gel electrophoresis 

[PFGE], polymerase chain reaction, terminal restriction fragment length polymorphism) or 

non-molecular. Non-molecular procedures can be biochemical (e.g., antibiotic resistance 

analysis, carbon utilization, F-specific coliphage typing, cell wall fatty acid methyl ester) or 

chemical (e.g., caffeine detection, optical brightener detection). In general, molecular 

methods can offer the most precise identification of specific types of sources, but they also 

have the highest unit costs and the most time-consuming procedures. Biochemical 

procedures are simpler, less expensive, and faster, and allow a larger number of samples to 

be analyzed in a shorter period of time (USEPA, 2002). The technology in this subject area 

is constantly evolving and new procedures and more refined methods may be available as 

research progresses. 

Zhang et al. (2003) described the use of the PFGE method of bacterial source tracking 

analysis on E. coli samples from Four Mile Run in Northern Virginia, which is a highly 

urbanized watershed with approximately 40 percent impervious surface. Four Mile Run is 

impaired due to bacterial contamination and has a TMDL in place to control bacterial 

sources. The PFGE analysis identified that waterfowl contribute 38 percent of the bacteria, 

humans and pets (combined) accounted for 26 percent, and raccoons contributed 25 percent. 

Deer (9 percent) and rats (11 percent) also contributed bacteria to Four Mile Run. 

DNA testing is an expensive but effective molecular method for identifying the primary 

animal or animals (human, duck, dog, etc.) that contribute microbes to the water column. 

More information about bacterial source tracking can be found in a two-part article in 

Stormwater available at http://www.forester.net/sw_0105_detecting.html (Hager, 2001). 

Antibiotic resistance analysis (ARA) is the most commonly used non-molecular method for 

tracking sources of bacteria. ARA is used to distinguish among sources by looking at 

patterns of antibiotic resistance found in bacteria from human and animal sources. Fecal 

bacteria from humans can exhibit greater resistance to certain antibiotics than bacteria from 

wildlife feces (Hager, 2001; USEPA, 2002). However, this method may be confounded by 

the presence of bacteria from agricultural operations such as feedlots or poultry operations 

where antibiotics are used. 

EPA’s Office of Research and Development’s National Risk Management Research 

Laboratory (NRMRL) is working to develop an integrated system for screening fecal bacteria 

contamination from various animal sources. NRMRL is working to match the best molecular 

method to its target bacteria for rapid screening and identification of sources of fecal 

contamination in watersheds (Simpson, 2003). 

(5) Measure nonpoint source loadings. It is possible to estimate the amount of pollutants 

transported in storm water runoff from various land uses by using empirical monitoring data, 

land use imperviousness and cover, area, and rainfall volume. Modeling of pollutant loads 

can establish baselines that can be used to determine whether changes have occurred as a 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

 Maryland’s Environmental Indicators

The state of Maryland has compiled several indicators to characterize environmental quality (MDE, 

1999). These indicators embody a range of environmental attributes, from air quality to drinking water 

quality to public understanding and community support. The Non-Tidal Aquatic Systems category, which 

encompasses the range of plants and animals found in free-flowing rivers, streams, lakes, and most 

wetlands, includes several indicators that appropriately address Maryland’s habitat and land uses and 

include physical, chemical, and biological measures: 

— Miles of Streams Degraded by Abandoned Mine Drainage. 

— Stream Miles Open to Migratory Fish. 

— Physical Habitat Index (Non-Tidal). 

— Benthic Macroinvertebrate Index of Biotic Integrity (Non-Tidal). 

— Fish Index of Biotic Integrity (Non-Tidal). 

— Riparian Forest Buffers. 

The biological indicators consider communities of living organisms as found throughout the water column 

rather than any individual species, and their values reflect the physical and chemical water quality 

conditions described by other indicators. The Riparian Forest Buffers indicator was chosen because of 

its importance to physical and chemical habitat and its contribution in cycling nutrients to aquatic species 

and because a statewide benchmark had already been established through the Chesapeake Bay 

Program. More information on Maryland’s environmental indicators is available at 

http://www.mde.state.md.us/enpa/ 2000_enpa/envi_indicators. 

result of land use changes or implementation of management practices. Loadings can be 

calculated for small-scale studies using the Simple Method as described in Controlling 

Urban Runoff: A Practical Manual for Planning and Designing Urban BMPs (Schueler, 

1987), which is available for purchase at http://www.mwcog.org. Alternatively, several 

computer simulation models are available to model changes in nonpoint source loads under 

different scenarios. 

Another source of information for estimating pollutant releases is the Healthy Community 

Environmental Mapping program, called HUD E-MAPS (HUD and USEPA, 2000). HUD 

E-MAPS, which was developed by the Department of Housing and Urban Development 

(HUD) and EPA, combines EPA environmental data with information on HUD’s community 

development and housing programs. The program provides location, type, and performance 

information on HUD-funded activities throughout the country, and select EPA pollution 

release information. The maps help communities to plan by allowing them to identify areas 

of pollutant releases when planning economic development and housing projects. The HUD 

E-MAPS program can be accessed at http://www.hud.gov/emaps. 

2.3.6 Establish Physical and Hydrological Indicators 

EPA’s Rapid Bioassessment Protocols for Use in Wadeable Streams and Rivers (USEPA, 1999) 

and Volunteer Stream Monitoring: A Methods Manual (USEPA, 1997c) provide guidance on 

how to conduct assessments of a water body’s physical, habitat, and hydrological characteristics. 

Both documents are available on the Internet: the former can be found at 

http://www.epa.gov/owow/monitoring/rbp, and the latter is located at 

http://www.epa.gov/owow/monitoring/volunteer/stream. 

2-16 
Management Measure 2: Watershed Assessment 

EPA also provides guidance for lake and reservoir monitoring in Lake and Reservoir 

Bioassessment and Biocriteria (USEPA, 1998b), which is available at 

http://www.epa.gov/owow/monitoring/tech/lakes.html. Monitoring guidance for estuarine and 

coastal marine waters can be found in Estuarine and Coastal Marine Waters: Bioassessment and 

Biocriteria Guidance (USEPA, 2000a), located at 

http://www.epa.gov/ost/biocriteria/States/estuaries/estuaries1.html. 

Additional monitoring guidance can also be obtained from EPA’s Environmental Monitoring and 

Assessment Program (EMAP), a research program designed to develop the necessary tools for 

monitoring and assessing the nation’s ecological resources. The objective of the program is to 

guide national monitoring initiatives and activities with improved scientific understanding of 

ecosystem integrity and dynamics. Information about the EMAP program is available at 

http://www.epa.gov/emap. 

Methods for characterizing streams are contained in Applied River Morphology (Rosgen, 1996). 

Rosgen discusses geomorphic characterization of streams, which helps to differentiate between 

degraded and stable stream systems. This book also contains methods used to assess the current 

conditions of a stream and the departure from its potential. The Bank Erodibility Hazard (BHI) 

Rating Guide can be used to quickly determine bank erosion potential. 

(1) Measure stream widening/downcutting. Measurements of stream width, depth, and bank 

characteristics taken over time can be used to indicate changes in the magnitude and 

frequency of storm flows caused by land use changes that affect stream geometry. Such 

measurements are also useful in identifying stream segments that are especially susceptible to 

erosion and areas where habitat is degraded to target areas for implementation of 

management practices. Many stream channels are already modified, so baseline conditions 

need to be established. This method cannot be used to predict changes, but it can help to 

diagnose a problem after it has occurred. Booth (1994) presents excellent guidance for 

conducting measurements of stream cross-sectional area. 

(2) Conduct physical habitat monitoring. Monitoring of physical habitat is used to assess the 

potential of the stream to support different kinds of biota. Parameters such as weather, 

stream type and origin, land use, erosion, reach width and depth, canopy, proportion of 

stream morphological type (pool, riffle, and run), and presence or absence of large woody 

debris and aquatic vegetation can be measured easily and inexpensively and can provide 

information about which taxa would likely be found in the stream without water quality 

impacts (reference condition). If conducted over time, monitoring can provide information 

about past, present, and future changes in channel morphology. Although this method 

detects impacts from relatively low levels of development, it is not useful in pinpointing 

sources of degradation, nor does it offer insight into other water quality impacts. 

(3) Assess dry weather flows. This method is used to assess the impact of urbanization on base 

flows, either as compared to a non-urbanized stream in the same ecoregion, or as a change 

over time. Impacted streams in humid areas show decreased flow, whereas perennial streams 

in arid regions show increased flow, as a result of urbanization. Evaluating pipe installations 

and impervious surfaces in humid regions and water use in arid regions allows this method to 

be used to identify causes of baseflow alteration. This method works well in conjunction 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

with stream widening/downcutting studies. It cannot be used to distinguish between 

urbanization and other causes of stream flow alteration such as irrigation, long-term drought, 

and the like, unless these factors are taken into account explicitly. Also, it is difficult to 

establish trends without extensive long-term data and knowledge about certain geologic 

conditions. 

(4) Measure flooding. It is important to quantify changes in stream morphology over time 

because alterations in stream size or shape or in floodplain boundaries indicate that 

hydrologic changes have resulted from development in the watershed. These changes can be 

identified by comparing historical floodplain records to current floodplain maps, called Flood 

Hazard Boundary Maps (FHBMs). They are official maps issued by a community 

administrator that detail the boundaries of the flood, mudslide, and related erosion areas 

having special hazards that have been designated (FEMA, 2000). The maps can be obtained 

from local community map repository sites, from the Federal Emergency Management 

Agency (FEMA) online at http://msc.fema.gov, or through FEMA by phone, fax, or mail 

from the Map Service Center, P.O. Box 1038, Jessup, Maryland 20794-1038; telephone 800-

358-9616; fax 800-358-9620. 

(5) Monitor stream temperature. This method identifies areas where stream temperature has 

increased as a result of urbanization and loss of shading and buffers. Stream temperature can 

be measured over time or compared to other, low-impact watersheds. This monitoring 

method can be used to identify areas that would potentially benefit from riparian buffer 

enhancement and to measure the effectiveness of management practices used to regulate 

stream temperature. Changes in stream temperature can be an early warning sign that 

sensitive species will be lost without intervention. Climatic conditions can cause variability 

in stream temperature that is extraneous to trends caused by urbanization and can confound 

analyses. In addition, in should be noted that some management practices, such as ponds and 

wetlands, can result in increased temperature. 

2.3.7 Establish Biological Indicators 

Bioassessments are useful for detecting aquatic life impairments and identifying the causative 

agents and possible mitigation strategies. Additional bioassessments can indicate whether 

mitigation was successful and can direct further management activities. Monitoring of biological 

communities offers the following advantages: 

— Biological communities reflect overall ecological integrity and directly relate to the 

primary goal of the Clean Water Act. 

— Biological communities integrate the effects of different stressors and provide a broad 

measure of their aggregate impact. 

— Biological communities provide an ecological measure of changes in environmental 

conditions. 

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Management Measure 2: Watershed Assessment 

— Use the models to generate and test indicators of urbanization and hydrologic change with 

respect to biological responses to these changes. 

— Use these indicators with the models to assess biological responses to alternative 

urbanization scenarios on larger scales. 

Data from satellite imagery, intensive water quality and biological sampling, stream cross-section 

measurements, and physical habitat assessments will be used to develop and test the models. A 

dynamic hydrology model that can simulate cross-sectional averaged velocities, shear stress 

velocities, and water depth variability during storm peaks has been developed. Functional biological 

metrics and habitat quality indices will be correlated not only to land use but also to channel 

morphometry and flow variability. 

For more information contact Anne Spacie, Department of Forestry and Natural Resources, Purdue 

University, 1159 Forestry Building, West Lafayette, Indiana 47907-1159; telephone 765-494-3621; email aspacie@purdue.edu. 

Development and Evaluation of Ecosystem Indicators for Urbanizing Midwestern Watersheds

Researchers at Purdue University are undertaking a study to develop predictive indicators of 

urbanization that are applicable to midwestern watersheds (Spacie et al., 2000). The objectives of this 

study are as follows: 

— Quantify impacts on hydrologic regimes, water quality, and habitat structure of stream 

ecosystems using paired experimental watersheds. 

— Develop linked models to accurately predict these impacts. 

— Routine biological monitoring is inexpensive compared to chemical monitoring and 

toxicity tests. 

— Biological monitoring is useful for evaluating impairment when criteria for specific 

ambient impacts do not exist. 

Bioassessments can include evaluation of fish populations, benthic macroinvertebrate 

communities, periphyton, and single species monitoring. EPA’s Rapid Bioassessment Protocols 

for Use in Wadeable Streams and Rivers (USEPA, 1999) contains descriptions of various 

methods for each community type. EPA (2000b) also published the Stressor Identification 

Guidance Document, which outlines a process to identify causes of biological impairment. The 

stressor identification process is outlined in Figure 2.2 and includes three major steps: (1) listing 

candidate causes of impairment; (2) analyzing new and existing data to generate evidence for 

each candidate cause; and (3) producing a causal characterization with the evidence generated in 

step 2 to draw conclusions about the stressors most likely to have caused the impairment. The 

Stressor Identification Guidance Document is available for download in PDF format at 

http://www.epa.gov/waterscience/biocriteria/stressors/stressorid.html or can be ordered through 

EPA’s National Service Center for Environmental Publications at 

http://www.epa.gov/ncepihom/index.htm. 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Detect or Suspect Biological Impairment

Decision-maker and Stakeholder Involvement

As Necessary: Acquire Data, Iterate Process

Stressor Identification

List Candidate Causes

Analyze Evidence

Characterize Causes

Eliminate Diagnose Strength of Evidence

Identify Probable Cause

The Biological Assessment of Wetlands Workgroup (BAWWG) (USEPA, 2001b) provides 

information for establishing monitoring protocols for wetlands through its series of “state of the 

science” reports. These reports include introductory modules on wetland bioassessments and 

modules on specific methods, such as bioassessments for macroinvertebrates. Although the 

reports do not provide specific prescriptive guidance, they summarize current knowledge and 

provide options and recommendations to states for developing wetland bioassessment methods 

and programs. The modules also point out limitations of current methods and identify research 

needs. Information from BAWWG is available at 

http://www.epa.gov/owow/wetlands/bawwg/index.html. 

(1) Assess periphyton populations. Changes in periphyton or plankton community structure and 

distribution patterns can indicate a water quality problem stemming from thermal pollution, 

toxic chemicals, nutrients, and sedimentation. Because periphyton have a short life cycle, 

they are especially good indicators of short-term impacts. Measurements of chlorophyll, a 

chemical common to all periphyton, can also be used as an indicator of eutrophication. 

Although there are several levels of sampling and analysis of periphyton populations, rapid 

sampling can be relatively easy and inexpensive and has little impact on the ecosystem. 

Figure 2.2: Conceptual diagram of the stressor identification process (USEPA, 2000b). 

Management Action:

Eliminate or Control Causes;

Monitor Results

Identify/

Apportion

Sources

Biological Condition Restored or Protected

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Management Measure 2: Watershed Assessment 

Also, standardized methods (biomass, chlorophyll) can be used to analyze and interpret algal 

communities without doing an extensive taxonomic evaluation, which requires specialized 

training. One problem with these indicators is that plankton populations vary seasonally and 

are highly transient, making them a poor indicator of site-specific conditions. 

(2) Assess macroinvertebrate assemblages. Macroinvertebrates are relatively immobile and are 

good indicators of site-specific effects. They have a short life cycle and therefore are good 

indicators of short-term stress. Measurements of invertebrate populations are usually 

compared to populations from a reference condition to determine the severity of pollutant 

impacts. The presence or absence of particular species can be used to infer poor aquatic 

integrity because macroinvertebrate assemblages typically cover a broad range of trophic 

levels and pollution tolerances that allow interpretation of multiple effects. 

Macroinvertebrate sampling has some drawbacks, including the fact that populations are 

highly habitat-dependent and vary with season, stream flow, and region, which can confound 

results. In addition, taxa identification requires training and can be complex and timeconsuming. Despite these drawbacks, volunteer monitoring programs can be used to collect 

macroinvertebrate data. Both Rapid Bioassessment Protocols for Use in Wadeable Streams 

and Rivers (USEPA, 1999) and Volunteer Stream Monitoring: A Methods Manual (USEPA, 

1997c) provide guidance on how to conduct benthic macroinvertebrate assessments. 

(3) Assess fish assemblages. Measurements of fish diversity, species richness, species pollutant 

tolerance, disease prevalence, and a variety of other metrics can be used to identify the nature 

and extent of a pollution or habitat problem. Measurements are taken in several different 

habitats within the stream or other water body and are usually compared to a regional 

reference condition to determine the extent of impairment. The methods can also be used to 

evaluate the success of management practices. Because fish have a relatively long lifespan, 

they often react to chronic levels of pollutants and long-term impacts. Fish are also easy to 

collect and identify. However, fish populations are influenced by many other variables, such 

as stream size, region, season, temperature, and flow conditions, that need to be taken into 

account when analyzing the data. Also, fish that migrate may be affected by conditions in 

another area that is not the area of interest. It is sometimes difficult to identify the source of 

problems in fish populations because of the prevalence of confounding factors that make 

interpretation of results difficult. 

Biodiversity information on the Web via NatureServe

NatureServe, a nonprofit organization, partners with a network of natural heritage programs and 

conservation data centers to conduct expert local biodiversity inventories and analyze the results both 

nationally and internationally. Their Web site offers such data products as the NatureServe Explorer, 

which compiles conservation data on more than 50,000 plants, animals, and ecological communities 

in the United States and Canada. Users can search the database by any combination of name, 

location, and conservation status. The Web site also links to online data resources available from 

natural heritage programs and conservation data centers via the “Local Program Data” link. 

NatureServe provides links to ecology, animal, and plant data for download and provides links to other 

biodiversity resources on the Web. The NatureServe Web site can be accessed at 

http://www.natureserve.org. 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

(4) Assess single species indicators. Trout, salmon, and freshwater mussels are often used for 

this type of assessment. Some species are popular with the public, and their popularity can 

help in rallying support for better management. Measuring only one species is relatively 

easy and inexpensive and might provide early diagnosis of degradation, which can facilitate 

remediation efforts. However, natural population fluctuations in a single species can skew 

results, and without corroborating evidence there is no way to prove conclusively that 

degradation has occurred. It should be noted that focusing on protecting a single species may 

decrease protection of other threatened species. 

(5) Measure composite indicators. This method typically involves developing an index that 

incorporates the results of several different bioindicators. Several metrics can be combined 

into a single integrity index, such as the number of native fish species or the number of 

intolerant macroinvertebrate taxa. Composite indicators provide a more comprehensive 

evaluation of storm water impacts than fish, macroinvertebrate, or single species indicators 

alone. Both long-term and short-term effects can be evaluated by using this type of metric. 

As with the other biological methods, populations are dependent on region, season, and flow. 

Reference site measurements are essential for valid comparisons when determining the extent 

of storm water impacts. Note: other measurements may be needed to identify sources of 

degradation. 

2.3.8 Establish Programmatic Indicators 

It is important to assess the effectiveness of a runoff management program. Claytor and Brown 

(1996) present several programmatic indicators that can be used to estimate the success of a 

management program and help to direct future efforts. These include: 

— Number of illicit connections identified or corrected 

— Number of management practices installed, inspected, and maintained 

— Permitting and compliance 

— Growth and development 

Management Measure 12 discusses other ways to determine the effectiveness of runoff 

management programs. 

2.3.9 Develop a Suite of Social Indicators 

Watershed managers can use several methods to gauge public perception of water quality issues 

and nonpoint source programs. These “social indicators” include: 

— Public attitude surveys 

— Industrial/commercial pollution prevention 

— Public involvement and monitoring 

— User perception 

More information about these indicators can be found in Environmental Indicators to Assess 

Stormwater Control Programs and Practices (Claytor and Brown, 1996). 

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Management Measure 2: Watershed Assessment 

2.4 Information Resources 

USGS’s NAWQA Data Warehouse provides online access for invertebrate community data from 

1,700 stream sites in more than 50 major river basins across the nation. Data from more than 

5,000 invertebrate community samples that were collected from 1993 through 2002 can be found 

here. The data warehouse also provides data on fish communities from more than 1,000 stream 

locations, as well as data from thousands of water quality samples from approximately 6,400 

stream sites, 7,000 wells, and streambed sediment and aquatic animal tissue. Samples have been 

analyzed for a number of constituents. The NAWQA Data Warehouse can be accessed at 

http://water.usgs.gov/nawqa/data. 

The Caltrans Guidance Manual: Storm Water Monitoring Protocols (Caltrans, 2000a) provides 

step-by-step descriptions of the processes used to plan and implement a successful water quality 

monitoring program specific to runoff from transportation-related facilities. Although the 

guidance manual emphasizes uniform policies and procedures for monitoring, the Statewide 

Storm Water Management Plan (Caltrans, 2000b) describes minimum procedures and practices 

Caltrans uses to reduce pollutants discharged from storm water drainage systems. These 

documents, along with other storm water-related documents, can be downloaded in PDF format 

http://www.dot.ca.gov/hq/env/stormwater/special/index.htm. 

Donigan and Huber (1991), in Modeling of Nonpoint Source Water Quality in Urban and NonUrban Areas, reviewed nonpoint source assessment procedures and modeling techniques for 

both urban and non-urban land areas. Detailed reviews of specific methodologies and models 

are presented, along with overview discussions focusing on both urban and non-urban methods 

and models. Brief case studies of ongoing and recently completed modeling efforts are 

described and recommendations for nonpoint runoff quality modeling are presented. This 

document can be ordered from the National Technical Information Service at www.ntis.gov or by 

calling 800-553-6847. 

EPA has assembled a Web site with information about and links to water quality models. This 

site includes basic information, EPA-supported models, other federal government-supported 

models, technical guidance for models, and model training and meetings. The Web site can be 

accessed at http://www.epa.gov/waterscience/wqm/. 

Patten et al. (2000) have undertaken a study to develop improved indicators and innovative 

techniques for assessing and monitoring ecological integrity at the watershed level in the western 

United States. Their objectives are to develop practical, scientifically valid indicators that span 

multiple resource categories, are relatively scale-independent, address different levels of 

biological organization, can be rapidly and cost-effectively monitored by remote sensing, and are 

sensitive to a broad range of anthropogenic and natural environmental stressors. More 

information about this project can be found at 

http://es.epa.gov/ncer_abstracts/grants/99/ecological/patten.html (NCER, 2001). 

Compendium of Tools for Watershed Assessment and TMDL Development (USEPA, 1997a) 

supports the watershed approach by summarizing available techniques and models that assess 

and predict physical, chemical, and biological conditions in water bodies. The publication 

contains descriptions of three major categories of models: watershed loading, receiving water, 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

and ecological. Watershed loading models can be used to simulate the generation and movement 

of pollutants from the source to discharge into receiving waters. Receiving water models can be 

used to simulate the movement and transformation of pollutants through lakes, streams, and 

rivers. Ecological models can be used to simulate plant and animal communities and their 

response to pollutants and habitat modification. This document is available through EPA’s 

National Service Center for Environmental Publications at 

http://www.epa.gov/ncepihom/index.htm. 

EPA’s Monitoring Guidance for Determining the Effectiveness of Nonpoint Source Controls

(USEPA, 1997b) contains an overview of nonpoint source pollution and covers the development 

of a monitoring plan, data analysis, quality assurance/quality control, and biological monitoring. 

The manual was written to assist users in the design of water quality monitoring programs to 

assess both impacts from nonpoint source pollution and the effectiveness of control practices and 

management measures. It is available through EPA’s National Service Center for Environmental 

Publications at http://www.epa.gov/ncepihom/index.htm. 

Volunteer Stream Monitoring (USEPA, 1997c) serves as a tool for program managers who want 

to launch a new stream monitoring program or enhance an existing program. It contains methods 

that have been adapted from those used successfully by existing volunteer programs. The 

guidance is available in HTML and PDF formats at 

http://www.epa.gov/owow/monitoring/volunteer/stream. 

The Lake and Reservoir Bioassessment and Biocriteria (USEPA, 1998b) guidance was 

developed through the experience of existing state, regional, and national lake monitoring 

programs and is oriented toward practical decision-making rather than research. Its primary 

target audiences are state and tribal natural resource agencies. It is intended to provide managers 

and field biologists with functional methods and approaches that will facilitate the 

implementation of viable lake bioassessment and biocriteria programs that meet their needs and 

resources. The document can be obtained in HTML format at 

http://www.epa.gov/owow/monitoring/tech/lakes.html. 

Rapid Bioassessment Protocols for Use in Wadeable Streams and Rivers: Periphyton, Benthic 

Macroinvertebrates, and Fish (USEPA, 1999) is a practical technical reference for conducting 

cost-effective biological assessments of lotic systems. This guidance is intended to provide basic, 

cost-effective biological methods for states, tribes, and local agencies that: (1) have no 

established bioassessment procedures; (2) are looking for alternative methodologies; or (3) may 

need to supplement their existing programs (not supersede other bioassessment approaches that 

have already been successfully implemented). The scope of this guidance is considered 

applicable to a range of planning and management purposes, i.e., the methods may be 

appropriate for priority-setting, point and nonpoint source evaluations, use-attainability analyses, 

and trend monitoring, as well as initial screening. The guidance is available in HTML and PDF 

formats at http://www.epa.gov/owow/monitoring/rbp. 

The Estuarine and Coastal Marine Waters: Bioassessment and Biocriteria Guidance

(USEPA, 2000a) provides an extensive collection of methods and protocols for conducting 

bioassessments in estuarine and coastal marine waters, as well as the procedures for deriving 

biocriteria from the results. Several case studies illustrate the bioassessment process and 

2-24 
Management Measure 2: Watershed Assessment 

biocriteria derivation procedures. This document can be downloaded in PDF format at 

http://www.epa.gov/ost/biocriteria/States/estuaries/estuaries1.html. 

The Stressor Identification Guidance Document (USEPA, 2000b) leads water resource managers 

through the process of stressor identification and evidence assembly. The guidance can be used 

whenever biological impairment is present in an aquatic ecosystem and the cause is unknown. 

The stressor identification process combines multiple methods to determine the causes of 

impairment, and the methods are presented in order of the kinds of evidence used, from sitespecific to more general information. The Stressor Identification Guidance Document is 

available in PDF format at http://www.epa.gov/waterscience/biocriteria/stressors/stressorid.html. 

Techniques for Tracking, Evaluating, and Reporting the Implementation of Nonpoint Source 

Control Measures: Urban (USEPA, 2000c) was written to assist local officials in focusing 

limited resources by using statistical sampling methods to assess, inspect, or evaluate a 

representative set of management practices, erosion and sediment controls, and onsite 

wastewater treatment systems. The document can be downloaded in PDF format at 

http://www.epa.gov/owow/nps/urban.pdf, or it can be ordered through EPA’s National Service 

Center for Environmental Publications at http://www.epa.gov/ncepihom/index.htm. 

EPA’s Web site titled “An Introduction to Water Quality Monitoring” contains a wide variety of 

resources for those interested in learning more about water quality monitoring, automated data 

management, and geographic information systems (USEPA, 2001). Many EPA guidance 

documents, fact sheets, and final reports are available from this site, which can be accessed at 

http://www.epa.gov/owow/monitoring/monitor.html.

EPA’s Web site, “Water Quality Criteria and Standards Plan” (USEPA, 1998d), describes six 

new criteria and standards program initiatives that EPA and the states and tribes will take over 

during the next decade. The plan presents a "vision" and strategy for meeting these important 

new initiatives and improvements and will guide EPA, states, and tribes in developing and 

implementing criteria and standards that provide a basis for enhancements to the TMDL 

program, NPDES permitting, nonpoint source control, wetlands protection, and other water 

resource management efforts. The Web site is located at 

http://www.epa.gov/ost/standards/quality.html. 

EPA’s Volunteer Monitoring Program provides technical assistance, serves as a regional contact 

for volunteer programs, manages grants to state agencies that undergo volunteer water 

monitoring and conduct public participation programs, and provides information exchange 

services for volunteers. The program’s Web site 

(http://www.epa.gov/owow/monitoring/volunteer) provides a link to a listserver is available for 

volunteer monitoring program coordinators, as well as a national newsletter for volunteer 

monitors, a directory of volunteer monitoring programs, and manuals on volunteer monitoring 

methods and on planning and implementing volunteer programs. 

EPA’s Watershed and Water Quality Modeling Technical Support Center provides information 

and services to federal agencies, state and local governments, businesses, and individuals to help 

support implementation of the Clean Water Act. Support includes reviewing proposed TMDLs, 

providing oversight to TMDL development nationwide, serving as technical advisors, applying 

 2-25 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

models for TMDL development, assisting in data acquisition and analysis, assisting in TMDL 

implementation, analyzing BMP design and performance, and researching models for regulatory 

applications. The center’s Web site can be accessed at 

http://www.epa.gov/athens/wwqtsc/index.html. 

The P8—Urban Catchment Model by Walker (2000) is designed to predict the generation and 

transport of runoff pollutants in urban watersheds. The model was developed to design and 

evaluate runoff treatment control combinations in developments for pollutant removal efficiency. 

The most recent version of this DOS-based program (Version 2.4, published in February 2000), 

as well as data files and program documentation, is available for download from 

http://wwwalker.net/p8. 

A useful water resource impact model is the Long-Term Hydrologic Impact Assessment 

(L-THIA), which was developed by Purdue University (2000) for land use planners to provide 

site-specific estimates of changes in runoff, recharge, and nonpoint source pollution resulting 

from past or proposed land use changes. The model uses regional climate data and user-provided 

location, land use, and soil group data for up to three different scenarios (past, present, and 

future). The results are in the form of tables, bar charts, and pie charts. The model is available at 

http://danpatch.ecn.purdue.edu/~sprawl/LTHIA7. 

Vermont’s Water Resources Board developed “A Scientifically Based Assessment and Adaptive 

Management Approach to Stormwater Management” as an appendix to the Investigation into 

Developing Cleanup Plans for Stormwater Impaired Waters (Docket No. INV-03-01). The 

assessment paper describes a framework for identifying storm water runoff problems and 

providing adaptive management to address controls for and treatment of runoff in problem areas. 

The framework represents a balance of the interests of many diverse constituents, focusing on 

surface water impairments and improvements to identify problems due to runoff and 

improvements due to runoff controls. The report, part of the Vermont Water Resources Board’s 

Stormwater Docket, can be accessed at http://www.state.vt.us/wtrboard/docs/inv-03-

01report.pdf. 

NatureServe, a nonprofit organization, partners with a network of natural heritage programs and 

conservation data centers to conduct expert local biodiversity inventories and analyze the results 

both nationally and internationally. Its Web site offers such data resources as the NatureServe 

Explorer, which compiles conservation data on more than 50,000 plants, animals, and ecological 

communities in the United States and Canada. Users can search the database by any combination 

of name, location, and conservation status. The Web site also connects to online data resources 

available from natural heritage programs and conservation data centers via the “Local Program 

Data” link. NatureServe provides links to ecology, animal, and plant data for download and to 

other biodiversity resources on the Web. The NatureServe Web site can be accessed at 

http://www.natureserve.org. 

2-26 
Management Measure 2: Watershed Assessment 

2.5 References 

Booth, D.B. 1994. A Protocol for Rapid Channel Assessment, Unpublished report. Surface 

Water Management Division, Water Resources Section, King County, WA. 

California Department of Transportation (Caltrans). 2000a. Guidance Manual: Storm Water 

Monitoring Protocols. CTSW-RT-00-005. California Department of Transportation, 

Sacramento, CA. 

California Department of Transportation (Caltrans). 2000b. Statewide Storm Water Management 

Plan. CTSW-RT-01-024. California Department of Transportation, Sacramento, CA. 

Caraco, D. 2001. The Watershed Model, Version 3.0. Prepared for U.S. Environmental 

Protection Agency by the Center for Watershed Protection, Ellicott City, MD. 

Center for Watershed Protection (CWP). 1999. Microbes and urban watersheds feature article 

VI: Resources for detecting bacterial sources. Watershed Protection Techniques

3(1):593–596. 

Claytor, R., and W. Brown. 1996. Environmental Indicators to Assess Stormwater Control 

Programs and Practices. Prepared for U.S. Environmental Protection Agency, 

Washington, DC, by Center for Watershed Protection, Ellicott City, MD. 

Donigian, A.S., and W.C. Huber. 1991. Modeling of Nonpoint Source Water Quality in Urban 

and Non-Urban Areas. EPA 600-3-91-039. U.S. Environmental Protection Agency, 

Office of Research and Development, Environmental Research Laboratory, Athens, GA. 

Driver, N.E., and G.D. Tasker. 1990. Techniques for Estimation of Storm-Runoff Loads, 

Volumes, and Selected Constituent Concentrations in Urban Watersheds in the United 

States. U.S. Geological Survey, Reston, VA. 

Federal Emergency Management Agency (FEMA). 2000. Map Service Center Products. 

http://msc.fema.gov. Last updated June 7, 2000. Accessed March 28, 2001. 

Hager, M.C. 2001. Detecting Bacteria in Coastal Waters. Stormwater Magazine 2(3): 16-25. 

http://www.forester.net/sw_0105_detecting.html. Accessed August 12, 2003. 

Hillegass, J.B. 2003. Using an Indicators Database to Measure Storm Water Program 

Effectiveness in Hampton Roads. In Proceedings, National Conference on Urban 

Stormwater: Enhancing Programs at the Local Level, February 17-20, 2003, Chicago, IL. 

MacDonald, L. 2000. Evaluating and managing cumulative effects: Process and constraints. 

Environmental Management 26(3):299–315. 

Maryland Department of the Environment (MDE). 1999. Maryland’s Environmental Indicators 

Status Report Summer 1999. Maryland Department of the Environment, Annapolis, MD. 

Last updated December 6, 1999. Accessed February 9, 2000. 

 2-27 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

National Center for Environmental Research (NCER). 2001. Developing Effective Ecological 

Indicators for Watershed Analysis. 

http://es.epa.gov/ncer_abstracts/grants/99/ecological/patten.html. Last updated August 

13, 2001. Accessed May 3, 2002. 

Omerink, J.M. 1987. Ecoregions of the conterminous United States. Annals of the Association 

of American Geographers 77(1):118–125. 

Patten, D.T., W. Minshall, R. Lawrence, and A. Marcus. 2000. Developing effective ecological 

indicators for watershed analysis. In 2000 STAR Ecosystem Indicators Progress Review 

Workshop. Proceedings of National Center for Environmental Research Workshop, Las 

Vegas, NV, May 8–10, 2000, p. 26. 

Pennsylvania Department of Environmental Protection (PDEP). 1999. Water Quality Initiatives 

in PA Act 167 Stormwater Planning. Pennsylvania Department of Environmental 

Protection, Harrisburg, PA. 

Purdue University. 2000. Impacts of Land Use Change on Water Resources.

http://danpatch.ecn.purdue.edu/~sprawl/LTHIA7. Last updated September 2000. 

Accessed March 28, 2001. 

Rosgen, D. 1996. Applied River Morphology. Wildland Hydrology books, Pagosa Springs, CO. 

Schueler, T. 1987. Controlling Urban Runoff: A Practical Manual for Planning and Designing 

Urban BMPs. Metropolitan Washington Council of Governments, Washington, DC. 

Simpson, J. 2003. DNA Based Molecular Methods for Bacterial Source Tracking in Watersheds. 

Presented at the EPA Science Forum, May 5-7, 2003, Ronald Reagan Building and 

International Trade Center, Washington, DC. 

Slawecki, T.A.D., R. Copp, and C. Zahorcak. No date. Application of a GIS Decision Support 

Tool to Urban Watershed Management in Fulton, County, Georgia. Limno-Tech, Inc., 

and Brown and Caldwell, Ann Arbor, MI. 

Smith, R.A., R.B. Alexander, and G.E. Schwarz. 2003. Natural Background Concentrations of 

Nutrients in Streams and Rivers of the Conterminous United States. Environmental 

Science and Technology 37(14): 3039-3047. 

Spacie, A., J.M. Harbor, M. Hondzo, and B.A. Engel. 2000. Development and evaluation of 

ecosystem indicators for urbanizing midwestern watersheds. In 2000 STAR Ecosystem 

Indicators Progress Review Workshop. Proceedings of National Center for 

Environmental Research Workshop, Las Vegas, NV, May 8–10, 2000, p. 49. 

U.S. Department of Housing and Urban Development (HUD) and U.S. Environmental Protection 

Agency (USEPA). 2000. HUD Environmental Maps E-MAPS. 

http://www.hud.gov/emaps. Last updated March 2000. Accessed March 28, 2001. 

2-28 
Management Measure 2: Watershed Assessment 

U.S. Environmental Protection Agency (USEPA). 1983. Final Report of the Nationwide Urban 

Runoff Program. U.S. Environmental Protection Agency, Water Planning Division, 

Washington, DC. 

U.S. Environmental Protection Agency (USEPA). 1997a. Compendium of Tools for Watershed 

Assessment and TMDL Development. EPA 841-B-97-006. U.S. Environmental 

Protection Agency, Office of Water, Washington, DC. 

U.S. Environmental Protection Agency (USEPA). 1997b. Monitoring Guidance for 

Determining the Effectiveness of Nonpoint Source Controls. EPA 841-B-96-004. 

U.S. Environmental Protection Agency, Office of Wetlands, Oceans, and Watersheds, 

Washington, DC. 

U.S. Environmental Protection Agency (USEPA). 1997c. Volunteer Stream Monitoring: A 

Methods Manual. EPA 841-B-97-003. U.S. Environmental Protection Agency, Office of 

Water, Washington, DC. 

U.S. Environmental Protection Agency (USEPA). 1998a. An Introduction to Water Quality 

Monitoring. U.S. Environmental Protection Agency, Office of Water, Washington, DC. 

http://www.epa.gov/owow/monitoring/monintr.html. Last updated December 14, 1998. 

Accessed February 2, 2000. 

U.S. Environmental Protection Agency (USEPA). 1998b. Lake and Reservoir Bioassessment 

and Biocriteria. EPA 841-B-98-007. U.S. Environmental Protection Agency, Office of 

Wetlands, Oceans, and Watersheds, Washington, DC. 

U.S. Environmental Protection Agency (USEPA). 1998d. Water Quality Criteria and Standards 

Plan. http://www.epa.gov/ost/standards/quality.html. Last updated July 2, 1998. 

Accessed May 2, 2002. 

U.S. Environmental Protection Agency (USEPA). 1999. Rapid Bioassessment Protocols for 

Use in Wadeable Streams and Rivers: Periphyton, Benthic Macroinvertebrates, and Fish. 

EPA 841-B-99-002. U.S. Environmental Protection Agency, Office of Wetlands, 

Oceans, and Watersheds, Washington, DC. 

U.S. Environmental Protection Agency (USEPA). 2000a. Estuarine and Coastal Marine 

Waters: Bioassessment and Biocriteria Guidance. EPA 822-B-00-024. U.S. 

Environmental Protection Agency, Office of Science and Technology, Washington, DC. 

U.S. Environmental Protection Agency (USEPA). 2000b. Stressor Identification Guidance 

Document. EPA-822-B-00-025. U.S. Environmental Protection Agency, Office of 

Research and Development, Washington, DC. 

U.S. Environmental Protection Agency (USEPA). 2000c. Techniques for Tracking, Evaluating, 

and Reporting the Implementation of Nonpoint Source Control Measures—Urban. EPA 

841-B-00-007. U.S. Environmental Protection Agency, Office of Wetlands, Oceans, and 

Watersheds, Washington, DC. 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

U.S. Environmental Protection Agency (USEPA). 2000d. Whole Effluent Toxicity (WET) 

Methods. http://www.epa.gov/OST/WET. Last updated August 1, 2000. Accessed 

March 28, 2001. 

U.S. Environmental Protection Agency (USEPA). 2001a. An Introduction to Water Quality 

Monitoring. http://www.epa.gov/owow/monitoring/monintr.html. Last updated 

June 11, 2001. Accessed May 6, 2002. 

U.S. Environmental Protection Agency (USEPA). 2001b. Biological Assessment of Wetlands 

Workgroup (BAWWG). http://www.epa.gov/owow/wetlands/bawwg/index.html. Last 

updated March 26, 2001. Accessed March 28, 2001. 

U.S. Environmental Protection Agency (USEPA). 2001c. Water Quality Criteria and Standards 

Program. http://www.epa.gov/OST/standards. Last updated March 6, 2001. Accessed 

March 28, 2001. 

U.S. Environmental Protection Agency (USEPA). 2002. Wastewater Technology Fact Sheet: 

Bacterial Source Tracking. EPA 832-F-02-010. U.S. Environmental Protection Agency, 

Office of Water, Washington, DC. 

Walker, W.W. 2000. P8—Urban Catchment Model: Program For Predicting Polluting Particle 

Passage Through Pits, Puddles, and Ponds. http://wwwalker.net/p8/. Accessed 

September 10, 2004. 

Zhang, H.X., J.T. Maurao, L.A. Fillmore, and J. Wheeler. 2003. Bacterial Source Tracking in 

Watershed Management and Source Water Protection. Presented at the AWRA 2003 

International Congress, June 29-July 2, 2003, New York, NY. 

2-30 
Management Measure 3: Watershed Protection 

MANAGEMENT MEASURE 3 

WATERSHED PROTECTION 

3.1 Management Measure 

Develop a watershed protection program to: 

— Avoid development of areas that are particularly susceptible to erosion and sediment loss. 

— Preserve areas that provide important water quality benefits and/or are necessary to 

maintain riparian vegetation and aquatic biota. 

— Site development projects, including roads, highways, and bridges, to protect the natural 

integrity of water bodies and natural drainage systems. 

3.2 Management Measure Description and Selection 

3.2.1 Description 

The purpose of this management measure is to reduce the generation of nonpoint source 

pollutants and to mitigate the impacts of urban runoff and associated pollutants from new 

development and redevelopment, including the construction of new and relocated roads, 

highways, and bridges. It is intended to provide general goals for local agencies and urban 

communities in developing comprehensive programs for guiding future development and land 

use activities in a manner that will prevent and mitigate the effects of nonpoint source pollution. 

Although the goals of this management measure and Management Measure 4 (Site 

Development) are similar, this measure is intended to apply to larger watersheds or regional 

drainage basins rather than individual sites. The watershed protection and site development 

management measures are intended to be complementary. They can be used together with the 

other management measures in a comprehensive framework to control runoff and reduce 

nonpoint source pollution. (See Chapter 1 for a description of the runoff management program 

framework.) 

Comprehensive planning is an effective nonstructural tool to control nonpoint source pollution. 

Where possible, growth should be directed toward areas where it can be sustained with minimal 

impact on the natural environment (Meeks, 1990). Poorly planned growth and development have 

the potential to degrade and destroy natural drainage systems and surface waters (Mantel et al., 

1990). By making proper planning and zoning decisions, water quality managers can direct 

development and land disturbance away from areas that drain to sensitive waters. Land use 

designations and zoning laws can also be used to protect environmentally sensitive areas such as 

riparian corridors and wetlands. 

 3-1 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Riparian buffers and wetlands can have the benefit of providing long-term pollutant removal 

capabilities without the comparatively high costs usually associated with constructing and 

maintaining structural controls. Conservation or preservation of these areas is important to 

protect the water quality of streams, wetlands, lakes, and reservoirs. Land acquisition programs 

help to preserve areas considered critical to maintaining surface water quality. Adequate buffer 

strips along streambanks provide protection for stream ecosystems, help stabilize the stream, and 

can prevent streambank erosion (Holler, 1989). Buffer strips can also protect and maintain nearstream vegetation that attenuates the release of sediment into stream channels. Levels of 

suspended solids have been shown to increase at a slower rate in stream channel sections with 

well-developed riparian vegetation (Holler, 1989). 

3.2.2 Management Measure Selection 

This measure was selected for several reasons. First, watershed protection is a technique that 

provides long-term water quality benefits, and many states and local communities have adopted 

this practice. Numerous state and local governments have already legislated and implemented 

detailed watershed planning programs that are consistent with this management measure. For 

example, Oregon, New Jersey, Delaware, and Florida have passed legislation that requires 

county and municipal governments to adopt comprehensive plans, including requirements to 

direct future development away from sensitive areas. Many municipalities and regions have 

adopted land use and growth controls, including the towns of Amherst and Norwood and the 

Cape Cod region of Massachusetts; Narragansett, Rhode Island; King County, Washington; and 

many others. 

Second, there is general recognition that the protection of sensitive areas and areas that provide 

water quality benefits is integral to maintaining or minimizing the impacts of development on 

receiving waters and associated habitat. Without a comprehensive planning approach that 

includes the use of riparian buffers, open space, bioretention, and structural controls to maintain 

the predevelopment hydrologic characteristics of the site, significant water quality and habitat 

impacts are likely. The experience of communities across the country has shown that the use of 

structural controls without adequate local land use planning and zoning often does not 

adequately protect water quality and might even cause detrimental effects such as increased 

temperature. 

Third, this measure is effective in producing long-term water quality benefits without the high 

operation and maintenance costs associated with structural controls. The Michigan Department 

of Environmental Quality (no date) compared the costs of two nonpoint source projects. One 

involved preserving an urbanizing watershed, and the other entailed restoring an urban 

watershed. Table 3.1 is a side-by-side cost comparison demonstrating that it is generally less 

costly to protect high-quality streams than to restore them. 

3-2 
Management Measure 3: Watershed Protection 

Table 3.1: Cost comparison of stream preservation vs. stream restoration (Michigan 

Department of Environmental Quality, no date). 

Bear Creek York Creek

Type of nonpoint source project Preservation Restoration 

Setting Grand Rapids, MI, area stream Grand Rapids, MI, area stream 

Size 20,096 acres 2,110 acres 

Level of urbanization 9.5% (1991) 19% (1993) 

Stream category High-quality trout stream Former trout stream 

Storm water ordinance $10,000 $10,000 

Decision-making GIS $10,000 $10,000 

Information/education program $100,000 $80,000 

Streambank stabilization $15,000 $130,000 

Storm water basin retrofits – $180,000 

Additional storm water basins – $75,000 

Other practices (habitat improvement, 

repairing road crossings, etc.) $75,000 $190,000 

Total cost $210,000a $675,000 a Total cost does not take into account the purchase cost or opportunity cost for not developing the land

3.3 Management Practices 

A comprehensive watershed approach requires constant adjustments based on development 

patterns, population increases, changing land uses, the state of the resources, and the institutional 

capacity of the community to manage its resources. The practices listed below provide an 

overview of the approaches communities around the country are adopting or experimenting with 

to protect their water resources in a cost-effective way. 

3.3.1 Resource Inventory and Information Analysis 

Before a comprehensive program can be developed, communities should define the watershed 

boundaries, target areas, and pollutants of concern, and conduct resource inventory and 

information analysis. These activities can be done by using the best available information or 

collecting primary data, depending on funding availability and the quality of available data. 

Activities pursued under this process include assessment of ground water and surface water 

hydrology; evaluation of soil type and ground cover; identification of areas with water quality 

impairments; and identification of environmentally sensitive areas, such as steep or erodible 

uplands, wetlands, riparian areas, floodplains, aquifer recharge areas, drainageways, and unique 

geologic formations. Once environmentally sensitive areas are identified, those that are integral 

to the protection of surface waters and the prevention of nonpoint source pollution can be 

protected. 

The City of Virginia Beach, Virginia, conducted a three-phase inventory of natural areas to help 

planners and public officials develop practices for resource protection. The data collection phase 

cost $13,867 (1991 dollars); the field inventory (Phase II), cost $54,624; and Phase III, 

preparation of a final report, cost $15,255 (Jenkins, 1991). 

Richmond County, Virginia, developed the Richmond County Resource Information System 

(RIS) to provide a basis for responsible planning and development of shoreline areas. The 

 3-3 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Watershed Approach to Storm Water and Flood Management

The Planning Department of Delaware County, New York, is leading the effort to develop long-term 

solutions to water quality impairment from urban runoff. The county’s Stormwater and Flood 

Management program uses a two-phase approach: (1) inventorying and assessing sources of urban 

runoff and storm water infrastructure, and (2) local implementation and municipal plan development. 

The inventory and assessment component involves a detailed evaluation of point and nonpoint 

sources of pollution in the Cannonsville Basin. Locations of potential sources were documented using 

a Global Positioning System and site characteristics such as soil type and land use were recorded. A 

GIS database was used to store this information along with existing infrastructure, topographic maps 

,and planimetric maps. 

The local implementation and municipal plan development component involves working with local 

municipalities as part of its Town Planning Advisory Service (TPAS) to develop local initiatives for 

water quality protection and to demonstrate the role of water quality in community economic 

development. The municipal plans help local officials integrate wellhead protection into water quality 

planning, prioritize management needs, establish maintenance programs, and incorporate runoff 

management into capital planning (Delaware County Departments of Planning and Public Works, 

2003).

compilation and mapping of resource information are part of the county's planning and zoning 

program. In 1990, the program was supported by a $39,000 Federal Coastal Zone Management 

Grant, $45,000 from the Chesapeake Bay Foundation through a Virginia Environmental 

Endowment Grant, and $96,000 from the county's comprehensive plan budget (Jenkins, 1991). 

3.3.1.1 Identify environmentally sensitive, critical conservation areas 

The identification of environmentally sensitive areas, also referred to as critical conservation 

areas, is an essential component of a watershed protection program. These areas need to be 

identified to: (1) avoid developing areas susceptible to erosion and sediment loss; and 

(2) preserve areas that provide important water quality benefits, such as wetlands, permeable 

soils, forested buffers, and riparian areas. These types of lands are described in Table 3.2. 

Inventories of these areas can be developed using wetland inventories, soil maps, maps of critical 

habitat for endangered species, GIS tools, remote sensing, vegetative cover inventories/maps, 

and forest inventories, among other sources. 

GIS Mapping for Open Space and Water Resource Protection

The towns of Westford, Littleton, Chelmsford, and Boxborough, located in the Merrimack River 

Watershed north of Boston, Massachusetts, are using GIS as a tool to guide efforts to protect critical 

open space lands and aquifers. The effort is part of Massachusetts’ Community Preservation Initiative, 

which helps local officials address the tradeoff between environmental planning issues, such as 

habitat and watershed protection, and the growing needs of the community in terms of economic 

development, housing, and transportation. GIS provides local officials with the capability of identifying 

open space lands that are critical to protecting water resources and exploring the implications of 

various build-out scenarios, land preservation strategies, land uses, and densities (NALGEP, 2003). 

3-4 
Management Measure 3: Watershed Protection 

Table 3.2: Types of lands that should be preserved for watershed protection (adapted from 

Caraco et al., 1998). 

Conservation Area Description Examples

Critical habitat Essential spaces for plant 

and animal communities or 

populations 

Tidal wetlands, freshwater wetlands, large forest 

clumps, springs, spawning areas in streams, habitat for 

rare or endangered species, potential restoration areas, 

native vegetation areas, coves 

Aquatic corridor Areas where land and water 

interact 

Floodplains, stream channels, springs and seeps, steep 

slopes, small estuarine coves, littoral areas, stream 

crossings, shorelines, riparian forest, caves, and 

sinkholes 

Hydrologic reserve Undeveloped areas 

responsible for maintaining 

the predevelopment 

hydrologic response of a 

subwatershed 

Forest, meadow, prairie, wetland, cropland, pasture, or 

managed forest 

Water pollution hazard 

Source: Stapleton, 1999. 

Any land use or activity 

that is expected to create a 

relatively high risk of water 

pollution 

Septic systems, landfills, hazardous water generators, 

aboveground or underground tanks, impervious cover, 

surface or subsurface discharge of wastewater effluent, 

land application sites, storm water “hot spots,” 

pesticide application, industrial discharges, and road 

salt storage areas 

Cultural and historic sites 

Source: NPS, 2001. 

Areas that provide a sense 

of place in the landscape 

and are important habitats 

for people 

Historic or archaeological sites, trails, parkland, scenic 

views, water access, bridges, and recreational areas

3.3.1.2 Identify and protect drinking water sources 

All drinking water sources, including surface and ground waters, should be considered for 

protection, and unfiltered sources will require the most stringent protection. More than 200 cities, 

towns, and tribes protect ground water public drinking water systems from contamination using a 

variety of local government tools such as zoning, subdivision controls, and transfer of 

development rights. The ordinances implementing these tools are varied and include measures 

 3-5 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

such as regulating onsite wastewater treatment systems and limiting nitrogen loading within 

wellhead protection areas (see section 1.3.1.2 in Management Measure 1, which describes 

different types of ordinances, including source water protection ordinances). This section 

introduces several tools to protect surface and ground water sources. Also, more information 

about identifying and protecting drinking water sources can be found at EPA’s Office of Ground 

Water and Drinking Water Web site at http://www.epa.gov/ogwdw. 

(1) Delineate a Source Water Protection Area. Delineation of a Source Water Protection Area 

requires identifying the boundaries of the area from which drinking water supplies are drawn. 

This information can be obtained from states, which are required to conduct an assessment of 

all public water systems. These assessments include a delineation, contaminant inventory, 

and susceptibility determination (see http://www.epa.gov/safewater/protect/swap.html for 

more information about state Source Water Assessment Programs). Local governments may 

choose to elaborate on the state's assessment before planning management activities. 

(2) Protect Sole Source Aquifers. Sole Source Aquifer (SSA) designations are one tool to protect 

drinking water supplies in areas with few or no alternative sources. These areas are of special 

significance because if contamination occurred, using an alternative source would be 

prohibitively expensive. The designation protects an area’s ground water resource by 

requiring EPA review of any proposed projects within the designated area that are receiving 

federal financial assistance. All proposed projects receiving federal funds are subject to a 

review to ensure they do not endanger the water source. Between January 1997 and January 

1999, EPA reviewed 439 projects, 60 of which required modifications that were deemed 

necessary to protect the Sole Source Aquifers. Examples of federally funded projects that 

have been reviewed by EPA under the SSA protection program include highway 

improvements and new road construction, public water supply wells and transmission lines, 

wastewater treatment facilities, construction projects that involve disposal of storm water, 

agricultural projects that involve management of animal waste, and projects funded through 

Community Development Block Grants. 

EPA has developed Memoranda of Understanding (MOU) with other agencies to help 

establish review responsibilities under the Sole Source Aquifer Protection Program and to 

clarify what types of projects should or should not be referred to EPA. If you have questions 

about whether EPA needs to review a project in a particular Sole Source Aquifer, please 

contact the Sole Source Aquifer Coordinator for your state or territory (see 

http://www.epa.gov/safewater/swp/sumssa.html for lists and maps of Sole Source Aquifers in 

each of the EPA regions along with contact information for Sole Source Aquifer 

Coordinators). 

(3) Develop a local wellhead protection ordinance. Wellhead protection refers to implementing 

pollution prevention and source controls to protect underground sources of drinking water. 

The Safe Drinking Water Act requires that State Wellhead Protection Programs be approved 

by EPA and incorporate delineation, contaminant source inventory, and source management. 

Local governments can also develop local wellhead protection ordinances to further protect 

drinking water supplies from contamination. 

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Management Measure 3: Watershed Protection 

(4) Purchase property or development rights. This practice is meant to guarantee community 

control over the activities conducted on lands that contribute to aquifers or surface waters. 

This may involve outright purchase of the land or just surface-use rights (see section 3.3.5 for 

a discussion of land acquisition options). New funds from the Safe Drinking Water Act allow 

land trusts and other local organizations to work with state agencies and water suppliers to 

identify and acquire critical lands and conservation easements. 

3.3.2 Development of Watershed Management Plan 

The resource inventory and information analysis component provides the basis for a watershed 

management plan, which is a comprehensive approach to addressing the needs of a watershed, 

including land use, urban runoff control practices, pollutant reduction strategies, and pollution 

prevention techniques. 

For a watershed management plan to be effective, it should have measurable goals describing 

desired outcomes and methods for achieving the goals. Goals, such as reducing pollutant loads to 

surface water by 25 percent, can be articulated in a watershed management plan. Development 

and implementation of urban runoff practices, both structural and nonstructural, can be 

incorporated as methods for achieving the goal. The following describes the general steps for 

developing a watershed management plan (Livingston and McCarron, 1992): 

1. Delineate and map watershed boundaries and subbasins within the watershed. 

2. Inventory and map natural runoff conveyance and storage systems. 

3. Inventory and map the manmade storm water conveyance and storage system. 

4. Inventory and map land use by subbasin. 

5. Inventory and map detailed soils by subbasin. 

6. Establish a clear understanding of water resources in the watershed. Analyze water 

quality, sediment, and biological data. Analyze subjective information on problems such 

as citizen complaints. Evaluate water body use impairment, including the frequency, 

timing, and seasonality of the problem. Conduct a water quantity assessment (e.g., low 

flows, seasonality). 

7. Inventory pollution sources in the watershed, including point sources (location, 

pollutants, loadings, flow capacity, etc.) and nonpoint sources (type, location, pollutants, 

loading, etc.). Include a land use/loading rate analysis for storm water, a sanitary survey 

for septic tanks, and dry weather flow monitoring to locate illicit discharges. 

8. Identify and map future land use by subbasin. Conduct land use loading rate analyses to 

assess potential effects of various land use scenarios. 

9. Identify planned short-term (five years) and long-term (20 years) infrastructure 

improvements. Runoff management deficiencies should be coordinated and scheduled 

with other infrastructure or development projects. 

10. Determine infrastructure and natural resource management needs within each watershed. 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

11. Set resource management goals and objectives. Before corrective actions can be taken, a 

resource management target must be set. The target can be defined in terms of water 

quality standards, attainment of beneficial uses, or other local resource management 

objectives. 

12. Determine pollutant reduction for existing and future land uses needed to achieve water 

quality goals. 

13. Select appropriate management practices for both point and nonpoint sources that can be 

used to achieve the goal. Evaluate pollutant removal effectiveness, landowner 

acceptance, financial incentives and costs, availability of land operation and maintenance 

needs, feasibility, and availability of technical assistance. 

14. Develop a watershed management plan. Since the problems in each watershed will be 

unique, each watershed management plan will be specific. However, all watershed plans 

will include elements such as an existing and future land use plan; a master storm water 

management plan that addresses existing and future needs; a wastewater management 

plan, including septic tank maintenance programs; and an infrastructure and capital 

improvements plan. 

Development of a watershed management plan may involve establishing general land use 

designations that define allowable activities on a parcel of land. For example, land designated for 

low-density residential use would be limited to a density of two houses per acre, provided that all 

other regulations and requirements are met. All development activities allowed in a use category 

should be defined. By guiding uses within the planning areas, impacts to surface waters from 

urban runoff can be controlled. Those areas identified in the resource inventory and information 

analysis phase as environmentally sensitive and important to maintaining water quality can be 

preserved through various measures supported by state or local goals, objectives, and policies. 

In Florida, local governments (counties and incorporated municipalities) were required to 

develop comprehensive plans based on existing information to guide short-term (five years) and 

long-term (20 to 25 years) growth and development. Local plans were required to be consistent 

with the state plan and the state growth management law and needed to identify environmentally 

sensitive areas and areas with water quality problems. 

The Environmental Quality Corridor (EQC) System was established in Fairfax County, Virginia, 

to preserve floodplains, wetlands, shoreline areas, and steep valley slopes. EQCs were defined in 

the county's comprehensive plan and identified on the county land use map. If a parcel of land 

subject to a zoning or land use designation change contained an EQC, it was required to be set 

aside by the developer as part of development approval. Since its initiation, tens of thousands of 

acres have been set aside through the EQC program. The cost of implementing the program is 

part of the operating budget of the county planning department. 

Howard County, Maryland, developed a Land Preservation and Recreation Plan as part of the 

county comprehensive plan. Under this plan, open space resources are purchased for preservation 

and recreation. The annual cost to update the plan, $25,000 (in 1991 dollars), is funded by the 

state. In FY 1990, the county received $1.14 million in state funds to update the plan and acquire 

land (Jenkins, 1991). 

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Management Measure 3: Watershed Protection 

3.3.3 Implement the Plan 

Once critical areas have been identified, land use designations have been defined, and goals have 

been established to guide activities in the watershed, implementation strategies can be developed. 

At this point, the requirements of future development are defined. These requirements include, 

but are not limited to, permitted uses, construction techniques, and protective maintenance 

measures. Land development regulations may also prescribe natural performance standards, such 

as “rates of runoff or soil loss should be no greater than predevelopment conditions.” 

A useful planning tool is the Long-Term Hydrologic Impact Assessment (L-THIA), which was 

developed by Purdue University (2000) for land use planners to provide site-specific estimates of 

changes in runoff, recharge, and nonpoint source pollution resulting from past or proposed land 

use changes. The model uses regional climate data and user-provided location, land use, and soil 

group data for up to three different scenarios (past, present, and future). The results are in the 

form of tables, bar charts, and pie charts. The model is available at 

http://danpatch.ecn.purdue.edu/~sprawl/LTHIA7. 

Listed below are examples of the types of development regulations and other implementation 

tools that have been successful at controlling nonpoint source pollution. 

3.3.3.1 Develop ordinances or regulations requiring nonpoint source pollution controls for 

new development and redevelopment 

These ordinances or regulations should address, at a minimum: 

− Control of off-site urban runoff discharges (to control potential impacts of flooding); 

− The use of source control BMPs and treatment BMPs; 

− The performance expectations of BMPs, specifying design storm size, frequency, and 

minimum removal effectiveness, as specified by the state or local government; 

− The protection of stream channels, natural drainageways, and wetlands; 

− Erosion and sediment control requirements for new construction and redevelopment; and 

− Treatment BMP operation and maintenance requirements and designation of responsible 

parties. 

3.3.3.2 Plan infrastructure 

Infrastructure planning is the multiyear scheduling and implementation of infrastructure 

improvements, such as roads, sewers, potable water delivery, landfills, public transportation, and 

urban runoff management facilities. Infrastructure planning can be an effective practice to help 

guide development patterns away from areas that provide water quality benefits, are susceptible 

to erosion, or are sensitive to disturbance or pollutant loadings. Where possible, long-term 

comprehensive plans to prevent the conversion of these areas to more intensive land uses should 

be drafted and adopted. Infrastructure should be planned for and sited in areas that have the 

capacity to sustain environmentally sound development. Development tends to occur in response 

to infrastructure availability, both existing and planned. New development should be targeted for 

areas that have adequate infrastructure to support growth in order to promote infill development, 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

prevent urban sprawl, and discourage the use of septic tanks where they are inappropriate 

(International City/County Management Association, 1979). Infill development may have the 

added advantage of municipal cost savings. 

To discourage development in the environmentally sensitive East Everglades area, Dade County, 

Florida, has developed an urban services boundary (USB). In areas outside the USB, the county 

will not provide infrastructure and has kept land use densities very low. This strategy was 

selected to prevent urban sprawl, protect the Everglades wetlands (outside of Everglades 

National Park), and minimize the costs of providing services countywide. The area is defined in 

the county comprehensive plan, and restrictions have been implemented through the land 

development regulations (Metro-Dade Planning Department, 1988). 

Congress has enacted similar legislation for the protection of coastal barrier islands. In 1981, the 

availability of federal flood insurance for new construction on barrier islands was discontinued. 

In 1982, Congress passed the Coastal Barriers Resources Act, establishing the Coastal Barrier 

Resource System (CBRS), and terminated a variety of federal assistance programs for designated 

coastal barriers, including grants for new water, sewage, and transportation systems. In 1988, 

similar legislation was passed for the Great Lakes area, adding 112 Great Lakes barrier islands. 

Additions to the CBRS in 1990 included parts of the Florida Keys, the U.S. Virgin Islands, 

Puerto Rico, and the Great Lakes (Simmons, 1991). 

The result of the legislation and subsequent additions to the CBRS has been the establishment of 

approximately 1,326,000 acres of barriers that are ineligible for federal assistance for 

infrastructure and flood insurance (U.S. Fish and Wildlife Service (USFWS), 2002). This act has 

helped to guide development away from these sensitive coastal areas to more suitable locations. 

USFWS (2002) estimates that more than a billion dollars may be saved between 1983 and 2010 

due to reduction of disaster relief and infrastructure construction costs. 

3.3.3.3 Revise local zoning ordinances 

Zoning is the division of a municipality or county into districts for the purpose of regulating land 

use. Usually defined on a map, the allowable uses within each zone are described in an official 

document, such as a zoning ordinance. Zoning is enacted for a variety of reasons, including 

preservation of areas that are environmentally sensitive or necessary to maintain environmental 

integrity (International City/County Management Association, 1979). 

Within zoning ordinances, subdivision regulations govern the process by which individual lots 

are created out of larger tracts of land. Subdivision regulations are intended to ensure that 

subdivisions are appropriately related to their surroundings. General site design standards, such 

as preservation of environmentally sensitive areas, are one example of subdivision regulations 

(International City/County Management Association, 1979). 

There are specific types of zoning ordinances that can be particularly useful in protecting water 

resources, including performance-based zoning, overlay zones, bonus or incentive zoning, largelot zoning, agricultural protection zoning, watershed-based zoning, and urban growth boundaries. 

The following provides an overview of each of these types of zoning: 

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Management Measure 3: Watershed Protection 

3.3.3.3.1 Performance-based zoning 

In performance-based zoning, developers are allowed flexibility in planning and designing the 

development as long as they meet minimum requirements set by the local government. These 

minimum requirements vary based on the particular resource protection objectives of the 

community but might include limiting the amount of impervious surfaces or preserving sensitive 

features such as wetlands or steep slopes with high erosion potential. Developers can choose lot 

sizes, building types, site layouts, and other development characteristics as long as they meet the 

minimum criteria. Performance-based zoning offers protection of natural resources for the 

community and increased flexibility for the developer. It requires greater effort on the part of the 

local government, however, to carefully tailor the language of the ordinance to ensure that 

resources are adequately protected, and to carefully review development proposals to ensure that 

performance criteria are met. 

Officials in Columbia, Missouri, were interested in developing a uniform policy to deal with 

storm water pollution (Tritto, 2000). This effort was initiated in response to a recent back-andforth battle between a developer and the Columbia City Council. Officials are reviewing a report 

developed by Missouri University researchers that evaluated the environmental sensitivity of 

13 watersheds in the Columbia area using 12 criteria focused on human health and 

environmental protection. The report recommended limits on the percentage of impervious 

surfaces for developments based on categories of watershed sensitivity. Developers would be 

allowed to exceed these limits only by taking additional steps to control storm water pollution 

through the use of management practices. The approach recommended in the report would 

provide a financial incentive for developers to direct high-density developments to less-sensitive 

watersheds because tougher standards on impervious areas and the costs of storm water controls 

would make it more expensive to develop in environmentally sensitive watersheds. City officials 

are also reviewing storm water management policies in other cities to develop uniform 

guidelines so that developers are better-informed about what is expected of them. 

3.3.3.3.2 Overlay zones 

Overlay zones superimpose additional restrictions on existing zoning categories to provide extra 

protection for a particular natural resource. For example, if a wetland or endangered species 

habitat crosses the boundaries of several development zones, an overlay zone can be established 

to limit development in areas that affect the wetland. Overlay zones can also be used to limit 

development in areas with highly permeable soils to protect an underground drinking water 

source from contamination. The overlay zones would maintain the general land use category, 

such as residential or commercial, but would require additional protection, such as greater limits 

on impervious area or special vegetation protection requirements. 

3.3.3.3.3 Bonus or incentive zoning 

Bonus or incentive zoning is another method to allow developers greater flexibility in return for 

preservation of open space and sensitive or environmentally significant features. With incentive 

zoning, a developer might be allowed to develop at a higher density than normally allowed if in 

return he or she preserves additional open space, creates a wetland, or reduces the site’s overall 

impervious area with underground parking, transportation modifications, or innovative site 

layouts. The success of bonus or incentive zoning is highly dependent on an individual 

developer’s perception of the economic benefits of additional density credits; therefore, this type 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

of zoning cannot be relied upon to protect natural resources. However, bonus or incentive zoning 

can encourage voluntary and economically beneficial protection for open space and sensitive 

features. 

3.3.3.3.4 Large-lot zoning 

Large-lot zoning establishes a very low density of development; individual dwellings are built on 

lots of 5 acres or more. Large-lot zoning is most effective when lots are very large (5 to 20 acres) 

(Caraco et al., 1998). The purpose of large-lot zoning is to spread development thinly, thereby 

conserving a large proportion of open space on each lot and reducing impacts on water resources. 

This method can produce undesirable results, however, including 

— Promoting sprawl; 

— Fragmenting habitats with more extensive infrastructure and lawns; 

— Increasing reliance on automobile transportation; and 

— Excluding lower-income residents who cannot afford to purchase large parcels of land. 

One approach to minimizing the negative impacts of large-lot zoning is to combine it with 

cluster zoning. In this way, a large area of open space can be protected, while accommodating 

new development in a more concentrated manner. Although used in many areas, large-lot zoning 

is not considered to be any more protective than other zoning tools. 

3.3.3.3.5 Farmland preservation zoning 

Farmland preservation ordinances are another type of measure to provide open space retention, 

habitat protection, and watershed protection. Farmland protection may be a less-costly means of 

controlling pollutant loadings than the implementation of urban runoff structural control 

practices. Much of the farmland currently being converted has soils that are stable and not highly 

erodible. Conversion of these farmlands often displaces farming activities to less-productive, 

more-erodible areas that may require increased nutrient and pesticide applications. 

Many communities consider both agriculture and forestry to be an integral part of rural heritage 

and strive to preserve these industries and the open space associated with them. According to the 

1997 National Resources Inventory, nearly 16 million acres of forest, cropland, and open space 

were converted to urban and other uses from 1992 to 1997. The average rate for those five 

years—3.2 million acres per year—is more than twice the conversion rate of 1.4 million acres 

per year recorded from 1982 to 1992 (USDA-NRCS, 2000). 

Agricultural lands can be protected by implementing a modified large-lot zoning ordinance that 

makes residential development less economically attractive. Alternatively, a cluster development 

ordinance can be established that specifies a density for an agricultural development and also 

requires that dwellings be built on small lots, leaving the remainder of the site as agricultural 

open space. The ordinance can also specify that development must occur on the least-productive 

part of the lot so the richest soils can be reserved for cultivation. 

Agricultural zoning ordinances can be combined with other initiatives to promote farming and 

forestry and to protect rural areas from being overtaken by urban sprawl (Sims, 2000b). The 

King County, Washington, executive official has undertaken several initiatives to promote 

diversity in lifestyle choices, encourage the continuation of farming and forestry, protect 

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Management Measure 3: Watershed Protection 

environmental quality and wildlife habitat, and maintain a link to the county’s heritage by 

preserving rural areas. So far the county has reduced its development rate in rural areas from 

15 percent in 1980 to 6 percent at present. The target is to further reduce the development rate to 

4 percent. The county issued orders to close loopholes in subdivision and land segregation 

regulations, and it tightened subdivision requirements for rural lands. These efforts will ensure 

that new development is consistent with current environmental and development standards. 

The county’s initiatives include maintaining an agricultural district as an “unincorporated urban 

area” to permanently protect this area from development pressures, establishing the Puget Sound 

Fresh program to promote locally grown and produced products, establishing a Farm Link 

program to connect farmers with land to sell or lease with those wishing to farm, and providing 

improved services for rural community centers. The county also established a Rural Forest 

Commission to encourage forestry and maintain the forest land base in the county’s rural areas. 

The county implemented a Farmlands Preservation Program, which has preserved 12,793 acres 

of agricultural lands through purchase or donation of development rights. Additionally, the 

county is able to preserve hundreds more acres of rural land each year through incentive-based 

taxation programs. Finally, King County’s 2000 Comprehensive Plan includes the following 

goals and initiatives: 

− Ensure that zoning complies with goals to reduce the rate of growth and protect the 

environment; 

− Ensure that the types and scale of development in the rural area blend with traditional 

rural development; 

− Implement recommendations from the forest commission to bolster King County’s forest 

and farming economies; and 

− Consider alternative uses of agricultural land, such as for wetland mitigation or 

recreation, such that these uses will not harm the integrity of agriculture in the county. 

More information about King County’s growth management initiatives can be found on the 

SmartGrowth Rural Legacy Web site at http://www.metrokc.gov/smartgrowth/rural.htm. 

3.3.3.3.6 Watershed-based zoning 

Historically, zoning has been used to establish limits on building density and to separate uses 

believed to be inherently incompatible (Arendt, 1997). Watershed-based zoning, in contrast, uses 

watershed and subwatershed boundaries as the basis for making land use decisions. Typically, 

zoning objectives focus on maintaining or reducing impervious cover in sensitive subwatersheds 

and redirecting development to subwatersheds that are better able to absorb their influence 

(Caraco et al., 1998). 

Local, state, and federal officials recently approved the Riverside County (California) Plan, 

which involved multi-agency cooperation in identifying where development may occur and 

where land should be preserved (Verden, 2000). Over the next 50 years, the Riverside County 

Plan will serve as a blueprint for building new roads, shopping centers, and homes, while also 

preserving rapidly disappearing habitat. The plan is designed to avoid costly delays and 

confrontations between regulators and developers. With the population of Riverside County 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

expected to double in 20 years, the plan will help developers accommodate growth while it also 

protects rare plants and animals. State and federal land, transportation, and wildlife managers 

hope the Riverside County Plan will be a model for other communities struggling to balance 

development and preservation. 

In 1992 Maryland enacted the Economic Growth, Resource Protection, and Planning Act to 

organize and direct comprehensive planning, regulating, and funding by state, county, and 

municipal governments in furtherance of a specific economic growth and resource protection 

policy (Maryland Department of Planning, no date). The policy is organized around seven 

statutory vision statements that must be pursued in county and municipal comprehensive plans 

where priorities for land use, economic growth, and resource protection are established. The 

seven statutory vision statements are: 

− Development is concentrated in suitable areas. 

− Sensitive areas are protected. 

− In rural areas, growth is directed to existing population centers and resource areas are 

protected. 

− Stewardship of the Chesapeake Bay and the land is a universal ethic. 

− Conservation of resources, including a reduction in resource consumption, is practiced. 

− To assure the achievement of the above, economic growth is encouraged and regulatory 

mechanisms are streamlined. 

− Funding mechanisms are addressed to achieve these visions. 

The visions must also be followed by the state in undertaking its various programs. Both state 

and local funding decisions on public construction projects must adhere to the visions. The Act 

also established an Economic Growth, Resource Protection, and Planning Commission to 

oversee, study, and report on progress towards implementation of the visions. More information 

about the act can be found at http://www.mdp.state.md.us/planningact.htm. 

3.3.3.3.7 Urban growth boundaries 

Urban growth boundaries are lines drawn around metropolitan areas to delineate where urban 

development can take place (inside the boundary) and where it may not (outside the boundary). 

Outside of urban growth boundaries, land use is restricted to agriculture, forestry, and open space 

(Nelson and Moore, 1993). The boundaries encourage more compact (i.e., infill) development, 

control urban sprawl, and help protect rural heritage. The approval process for new development 

can be streamlined within the growth boundary to further encourage development in these areas. 

The duration or lifespan of growth boundaries is normally related to planning periods or cycles, 

typically 10 to 20 years. Boundaries should be examined at regular planning intervals, however, 

to assess whether conditions have changed since they were established. 

Establishing the location of urban growth boundaries sometimes requires complex decisionmaking. Officials should be reasonably sure that there is sufficient land within the boundary to 

meet projected growth over the planning period and that public facilities and services can be 

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Management Measure 3: Watershed Protection 

provided at reasonable cost in a timely fashion. The potential impact of growth within the 

boundary on existing natural resources also needs to be determined. In the context of watershed 

planning, it is advantageous to use watershed boundaries or other natural features as urban 

growth boundaries. In this manner, key or sensitive watersheds can be protected from the 

impacts of development. 

In Arizona, the 1998 Growing Smarter Act and its 2000 addendum, Growing Smarter Plus, were 

signed into law by Governor Jane Hull (Morrison, 2000). This legislation addresses the issue of 

development by strengthening the ability of communities in Arizona to plan for growth and to 

acquire and preserve open space. The Growing Smarter legislation requires communities to 

address growth and growth-related pressures by mandating general plans that identify growth 

areas, establish policies and strategies for new growth, identify open space needs, regionally plan 

for interconnected open space, and analyze the environmental impacts of the development 

anticipated by the general plan (City of Tucson, no date).

3.3.3.4 Establish limits on impervious surfaces, encourage open space, and promote 

cluster development 

As described earlier, urban runoff contains high concentrations of pollutants washed off 

impervious surfaces (roadways, parking lots, loading docks, etc.). By retaining the greatest area 

of pervious surface and maximizing open space, nonpoint source pollution due to runoff from 

impervious surfaces can be kept to a minimum. Refer to section 4.3.2 for a detailed discussion of 

site design practices to reduce impervious surfaces in new developments. 

The following are examples of successful implementation of open space requirements and cluster 

development: 

− Brunswick, Maine, recently adopted an allowable impervious area threshold of 5 percent 

of any site to be developed in the defined coastal protection zone. The remaining 

95 percent is required to be left natural or landscaped. The threshold was developed and 

adopted using a $28,000 grant. 

− Virginia provides general guidance with regard to minimum open space and maximum 

impervious areas to local governments within the Chesapeake Bay watershed. While 

specific requirements are not associated with the guidance, local plans are required to 

contain criteria and must be approved by the Chesapeake Bay Local Assistance Board. 

− Carroll County, Maryland, is a community with substantial farmland and open space. 

Because it is located close to both Baltimore and Washington, DC, the county amended 

its zoning ordinance to encourage cluster development and preserve open space. This and 

land protection efforts by Carroll County have resulted in protection of 33,000 acres by 

agricultural easements (Maryland Environmental Trust Land Conservation Center, 2002). 

− Maryland adopted the Forest Conservation Act of 1991, which requires all public 

agencies and private landowners submitting a subdivision plan or application for a 

sediment control permit for an area greater than 40,000 square feet to develop a plan for 

retention of existing forest cover on-site. The act allows clearing that is essential to site 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

development, and it established a forest conservation fund for reforestation projects. In 

the first five years of implementation, the Forest Conservation Act has produced 22,508 

acres of retained forest and 4,313 planted acres, while 12,210 acres of existing forest 

have been cleared (Honeczy, 2000). 

− Broward County, Florida, has an open space program and encourages cluster 

development to reduce impervious surface area, protect water quality, and enhance 

aquifer recharge (Broward County, Florida, 1990). 

− New Hampshire has a model shoreland protection ordinance that encourages grouping of 

residential units, provided a minimum of 50 percent of the total parcel remains as open 

space. 

One way to increase open space while allowing reasonable development of land is to encourage 

cluster development. Clustering entails decreasing the allowable lot size while maintaining the 

number of allowable units on a site. Such policies provide planners the flexibility to site 

buildings on more suitable areas of the property and leave environmentally sensitive areas, such 

as wetlands or steep slopes, undeveloped. Criteria can vary. Advantages of cluster development 

include: 

— Reducing the costs of infrastructure; 

— Preserving sensitive areas; 

— Increasing property values with proximity to open space; and 

— Preserving ecological, aesthetic, and recreational values. 

Planned unit development is a type of zoning that encourages the use of cluster development but 

does not require it. For example, a set number of units could be spread across the site under 

typical residential zoning, but under cluster zoning, the same number of units could be 

concentrated on smaller lots on only a portion of the site, preserving the other portion for 

common open space to protect sensitive features or for use as a recreation area. 

3.3.3.5 Revitalize existing developed areas 

Redeveloping existing areas can alleviate water quality impacts by reducing the strain of 

development on open space land and minimizing the amount of impervious surface added to the 

watershed. Existing impervious surfaces, such as declining shopping malls and retail centers, can 

provide large tracts of developable land and are a prime opportunity for mixed-use infill 

development. For additional discussion of options for revitalizing urban areas, see Management 

Measure 10—Existing Development. 

3.3.3.6 Establish setback (buffer zone) standards 

In coastal areas, setbacks or buffer zones adjacent to surface water bodies, such as rivers, 

estuaries, or wetlands, provide a transition between upland development and these water bodies. 

The use of setbacks or buffer zones may prevent direct flow of urban runoff from impervious 

areas into adjoining surface waters and provide pollutant removal, sediment attenuation, and 

infiltration. Riparian forest buffers function as filters to remove sediment and attached pollutants, 

3-16 
Management Measure 3: Watershed Protection 

as transformers that alter the chemical composition of compounds, as sinks that store nutrients 

for an extended period of time, and as a source of energy for aquatic life (USEPA, 1992). 

Setbacks or buffer zones are commonly used to protect coastal vegetation and wildlife corridors, 

reduce exposure to flood hazards, and protect surface waters by reducing and cleansing urban 

runoff (Mantel et al., 1990). The types of development allowed in these areas are usually limited 

to non-habitable structures and those necessary to allow reasonable use of the property, such as 

docks and unenclosed gazebos. 

Factors for delineating setbacks and buffer zones vary with location and environment and 

include: 

− Seasonal water levels; 

− Nature and extent of wetlands and floodplains; 

− Steepness of adjacent topography; 

− Type of riparian vegetation; 

− Quantity and velocity of runoff entering the buffer; 

− Soil types and infiltration capacity; 

− Density of development adjacent to the riparian corridor; and 

− Wildlife values. 

It is important that sheet flow, not concentrated flow, be directed to the buffer. High-velocity 

runoff from steeply sloped or highly impervious areas can promote excessive erosion and 

decreased pollutant removal. A flat, grassy area or a level spreader can be installed at the upland 

part of the buffer to slow the velocity of runoff and promote sheet flow. It is also important to 

consider that the pollutant removal capacity of a buffer is finite and can be exceeded in areas 

with high concentrations of pollutants in runoff. 

Buffer width is an important measure of pollutant removal effectiveness. Buffers typically range 

from 20 to 200 feet wide and should include the 100-year floodplain, riparian areas including 

adjacent wetlands, steep slopes, or critical habitat areas (Schueler, 1995). A buffer at least 

100 feet wide is recommended for water quality protection, and a 300-foot buffer is 

recommended to maintain a wildlife habitat corridor. Wider buffers offer increased detention 

times, infiltration rates, and diversity of soil, vegetation, and wildlife. 

According to Herson-Jones et al. (1995), forested buffers achieve 50 percent TSS removal; 23 to 

96 percent phosphorus removal depending on the extent of TSS removal; greater than 40 percent 

lead removal; more than 60 percent copper, zinc, aluminum, and iron removal; and more than 

70 percent oil and grease removal. 

Overall, aquatic buffers are highly effective at removing particulate pollutants, but less effective 

in removing soluble pollutants (such as nitrogen, for which documented removal rates range 

from -15 to 99 percent). Proper siting and design and regular maintenance enhance removal 

efficiency. 

In general, EPA recommends that no habitat-disturbing activities should occur within tidal or 

non-tidal wetlands. In addition, a buffer area should be adequate to protect the identified wetland 

values. Minimum widths for buffers should be 50 feet for low-order headwater streams, with 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

expansion to as much as 200 feet or more for larger streams. In coastal areas, a 100-foot 

minimum buffer of natural vegetation landward from the mean high tide line helps to remove or 

reduce sediment, nutrients, and toxic substances entering surface waters. 

3.3.3.6.1 Buffer ordinance 

Buffer ordinances provide guidelines for buffer creation and maintenance. They should include 

the following provisions: 

— Buffer boundaries to be clearly marked on local planning maps; 

— Maintenance language that restricts vegetation and soil disturbance; 

— Tables that illustrate buffer width adjustment by percent slope and type of stream; and 

— Direction on allowable uses and public education. 

A model ordinance and examples of buffer ordinances from across the country can be found at 

http://www.epa.gov/owow/nps/ordinance. Buffer ordinances and other water resource-related 

ordinances are also described in section 1.3.1.2. 

The following are examples of setback or buffer requirements: 

− Town commissioners in Apex and Cary, North Carolina, have agreed to set wider buffers 

between development and streams (Price, 2000). Under the new ordinance, buffers must 

be at least 50 feet wide along intermittent streams and must average 100 feet wide along 

perennial streams. The towns chose to use an average rather than a strict 100-foot 

minimum to allow landowners flexibility. In addition to the buffer ordinance, Apex and 

Cary halved the limit of impervious surfaces on a given tract of land over which retention 

ponds are required to control runoff (from 24 percent to 12 percent). Town officials will 

hold a public hearing to vote on the new regulations. 

− Monroe County, Florida, requires a setback of 20 feet from high water on man-made or 

lawfully altered shorelines for all enclosed structures and 50 feet from the landward 

extent of mangroves or mean high tide line for natural water bodies with unaltered 

shorelines (Monroe County, Florida, Code, Section 9.5-286). 

− Brunswick, Maine requires a buffer of 125 to 300 feet from mean high water within the 

Coastal Protection Zone (Section 315 of the Brunswick Zoning Ordinance), depending on 

the slope of the buffer, as designated on the town's land use map. 

− Queen Anne's County, Maryland, established a standard shore buffer of 300 feet from the 

edge of tidal water or wetland, 50 percent of which must be forested. 

− Maryland’s Critical Area Act requires the establishment of a minimum buffer of 100 feet 

of natural vegetation landward from the mean high-water line of tidal waters or the edge 

of tidal wetlands and tributary streams. Unless a property owner can demonstrate 

unwarranted hardship and prove no negative impact to water quality, plant, fish or 

wildlife habitat, the local jurisdiction will not permit disturbance or new development 

within the buffer except for access or water-dependent facilities. Any clearing that occurs 

for access or water-dependent facilities must be mitigated through a buffer management 

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Management Measure 3: Watershed Protection 

plan approved by the local jurisdiction (Critical Area Commission for the Chesapeake 

and Atlantic Coastal Bays, no date). 

3.3.3.6.2 Vegetative and use strategies within management zones 

Buffers can be divided into three zones—the streamside, middle, and upland zones (HersonJones et al., 1995). Dense vegetation in the streamside zone (recommended to be approximately 

25 feet wide) prevents excessive activity in this sensitive area, maintains the physical integrity of 

the stream, and provides shade, litter, debris, and erosion protection. The width of a grassed or 

mostly forested middle zone (minimum of 50 feet) depends on the size of the stream and its 

floodplain and the location of protected areas such as wetlands or steep slopes. The upland zone, 

typically 25 feet wide, is an additional setback from the buffer and usually consists of lawn or 

turf. Zones in the buffer should be delineated to determine the types of vegetation that should be 

maintained or established. 

Allowable land uses in the three zones vary. The streamside zone is limited to footpaths, runoff 

channels, and utility or roadway crossings. The middle zone may be used for recreation and 

runoff control practices. The upland zone may be used for many purposes, with the exception of 

septic systems, permanent structures, or impervious covers. A depression incorporated into the 

design of the upland zone can detain runoff during storms. This runoff is released slowly to the 

middle zone as sheet flow, which is then transferred to the dense streamside zone, designed to 

have minimal to no discharge of surface water to the stream. 

3.3.3.6.3 Provisions for buffer crossings 

Stream crossings should minimize impacts on buffer integrity while providing crossing points for 

linear forms of development such as roads, bridges, golf course fairways, underground utilities, 

enclosed storm drains, and outfall channels (Schueler, 1995). They should also be designed to 

provide fish passage and to withstand overbank flows from the 100-year storm event. Design 

considerations for buffer crossings include: minimizing the width of the crossing; orienting the 

crossing at a right angle to the stream; limiting the total number of crossings; ensuring that 

outfalls discharge at the invert elevation of the stream channel; and burying utility crossings at 

least 3 feet below the channel’s invert elevation. An outfall should not be placed directly in the 

main channel. Energy-dissipating devices can be installed in outfalls to protect the streambed and 

adjacent banks. 

3.3.3.6.4 Integration of structural runoff management practices where appropriate 

Depressions can be incorporated into the upland part of a stream buffer to provide runoff 

detention during storms and to promote sheet flow over the middle zone of the buffer. A flat, 

grassed area or level spreader can also be used in the upland part of the buffer to create sheet 

flow and to promote infiltration over the rest of the buffer. 

Storm water ponds and wetlands can be located inside or outside the buffer. According to 

Schueler (1995), ponds inside the buffer should be used only for runoff quantity control. 

Although ponds in the buffer treat the greatest possible drainage area, are more likely to maintain 

their water level during dry periods, provide a diversity of aquatic habitats, and can increase the 

total width of the buffer, they displace vegetation and might cause barriers to fish migration, 

modification of existing wetlands, and stream warming. 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

3.3.3.6.5 Development of buffer education and awareness programs 

Buffer education efforts should foster community awareness and encourage stewardship. These 

objectives can be met by posting signs along the buffer boundaries that describe allowable 

activities in different parts of the buffer. Buffer owners can be educated by distributing 

pamphlets, hosting stream walks, and holding meetings. New owners should be made aware of 

buffer limits and allowable uses when the property is transferred. Buffer stewardship can be 

encouraged through reforestation and “bufferscaping” programs. Annual inspections can be done 

with “buffer walks” to determine the extent of encroachment, devegetation, erosion, or excessive 

sediment deposition. 

3.3.3.7 Establish slope restrictions 

Slope restrictions can be effective tools to control erosion and sediment transport. Erosion rates 

depend on several site-specific factors including soil type, vegetative cover, and rainfall 

intensity. In general, as slope increases, there is a corresponding increase in runoff water 

velocity, which may result in increased erosion and sediment transport to surface waters (Dunn 

and Leopold, 1978). 

3.3.3.8 Promote urban forestry 

Urban forestry is an effective tool for protecting watersheds because it can provide some of the 

storm water management required in urban areas. Trees decrease runoff by intercepting rain and 

promoting infiltration. This reduces the peak runoff flow and the total runoff volume that 

communities must manage, which can be financially beneficial to communities that have to build 

and maintain sewer and drainage systems (ENN, 2001). Also, trees provide shade, which lowers 

the temperature of urban heat islands and runoff. Erosion and leaf litter in forested areas can 

contribute sediment and nutrients to receiving waters; therefore, an effort should be made to 

establish and maintain stable vegetation and to keep leaf litter on-site. 

Several organizations dedicated to promoting urban forestry can provide information and other 

resources to interested groups or individuals. For example, American Forests 

(http://www.americanforests.org) is a conservation organization that is working to improve the 

environment with trees and forests. The organization’s Urban Forest Center offers tools to 

measure the environmental benefits of trees, such as pollution reduction and storm water 

management. These tools include the Regional Ecosystem Analysis (REA) and CITYgreen 

software packages. REA uses a combination of satellite data, field surveys, CITYgreen software, 

and other GIS technology to measure a region's or city's tree canopy and calculate its dollar 

value. CITYgreen allows users to compare the economic benefits of various planning scenarios 

by testing landscape ordinances, evaluating site plans, and modeling development scenarios that 

capture the benefits of trees. An application of this tool in Fayetteville, Arkansas, found that 

increasing the city’s tree cover from 27 to 40 percent could result in cost savings from runoff 

reduction of up to $135 million (NALGEP, 2003). Information about the software is available at 

http://www.americanforests.org/productsandpubs/citygreen/. 

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Management Measure 3: Watershed Protection 

TreePeople is another forestry organization. It works with the U.S. Forest Service and has 

enlisted the help of thousands of students and volunteers to plant seedlings in the mountains 

around Southern California. Its mission is to inspire people to take responsibility for improving 

their immediate environment. Information about TreePeople is available at 

http://www.treepeople.org/. 

Houston’s Urban Forests 

American Forests conducted a study of a 3.2 million-acre area in Houston to document urban forest 

cover (ENN, 2001). They also analyzed 25 individual sites with aerial photography using CITYgreen to 

map and measure tree cover and to calculate the benefits of Houston’s trees. Study results show that 

trees provide significant benefits in storm water runoff reduction, energy savings, and pollutant removal. 

The study found that Houston’s tree cover reduces the need for storm water management by 2.4 billion 

cubic feet per peak storm event, saving $1.33 billion in one-time construction costs. As a result, 

American Forests made the following recommendations to the city of Houston: 

• Improve green infrastructure by using tree cover data in land-use planning; growth 

management; and all transportation, public works, and development decision-making. 

• Encourage the use of increased tree cover to met storm water needs. 

• Work to increase tree cover in the metropolitan area. 

3.3.3.9 Use site plan reviews and approval 

A site plan review involves review of specific development proposals for consistency with the 

laws and regulations of the local government of jurisdiction. Potential development sites should 

be inspected to ensure that natural resources necessary for protecting surface water quality are 

preserved. Inspection ensures that the information presented in any application for development 

is accurate and that sensitive areas are noted for preservation. Inspections should also be 

conducted during and after development to ensure compliance with development conditions. 

Depending on the size of the local government and the amount of new development, this 

inspection could be incorporated into the duties of existing staff at minimal additional cost to the 

local government, or the inspection could require the addition of staff to conduct onsite 

inspections and monitoring. The effectiveness of such a program depends on the ability of the 

inspectors to evaluate property for its natural resource value and the practices used to protect 

areas necessary for the preservation of water quality. 

Development approvals should contain conditions requiring maintenance of the area’s 

environmental integrity and prevention of degradation from nonpoint source pollution, consistent 

with the goals, objectives, and policies of the comprehensive program and the requirements of 

the land development regulations. The criteria for new development are outlined as part of a 

development permit. Examples include the following: 

− Areas for preservation or mitigation may be identified, similar to the Fairfax County 

Environmental Quality Corridor System (see section 3.3.2). 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

− The use of nonstructural and structural management practices described in this chapter 

for controlling nonpoint source pollution may be a condition of development approval. 

− Setbacks and limits on impervious areas may be clearly defined in a condition for 

development approval, as is being done in the programs discussed above. 

− Reduction in the use of pesticides and fertilizers on landscaped areas by encouraging the 

use of vegetation that is adaptable to the environment and requires minimal maintenance. 

(Xeriscaping techniques are described in Management Measure 4 and lawn and garden 

activities are described in Management Measure 9.) 

3.3.3.10 Designate an entity or individual responsible for maintaining the infrastructure, 

including urban runoff management systems 

The responsible party should be trained in the maintenance and management of urban runoff 

management systems. If desired, the local government could be designated to maintain urban 

runoff systems, with financial compensation from the developer. Because they are not usually 

trained in infrastructure maintenance, homeowners groups are not the best entity for monitoring 

infrastructure for adequacy, especially urban runoff management systems. This responsibility 

should belong to a responsible party that understands the complexity of urban runoff 

management systems, can determine when such systems are not functioning properly, and has 

the resources to correct the problem. Again, this is a duty that the local government can assume, 

with either existing staff or additional staff, depending on the size of the local government and 

the amount of new development occurring. The amount of funding needed depends on the size of 

the local government. 

3.3.3.11 Use official mapping 

Official maps can be used to designate and/or protect environmentally sensitive areas, zoning 

districts, identified land uses, or other areas that provide water quality benefits. When approved 

by the local governing body, these maps can be used as legal instruments to make land use 

decisions related to nonpoint source pollution. 

3.3.3.12 Require environmental impact assessment statements 

To evaluate the impact that proposed development may have on the natural resources of an area, 

some counties and municipalities require an environmental assessment as part of the 

development approval processes. These assessments can be incorporated into the land 

development regulation process. Areas to be covered include geology, slopes, vegetation, 

historical features, wildlife, and infrastructure needs (International City/County Management 

Association, 1979). 

3.3.4 Cost of Planning Programs 

The cost of planning programs depends on a variety of factors, including the level of effort 

needed to complete and implement a program. Many of the practices described in this section 

can be incorporated into ongoing activities of a state or local government. 

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Management Measure 3: Watershed Protection 

The Florida legislature funded the development of comprehensive programs and land 

development regulations required by the Local Government Comprehensive Planning and Land 

Development Regulation Act (1985). Distribution of funds was based on population according to 

formulas used for determining funding for the plan and land development regulations. A base 

amount was given to all counties that requested it. The balance of the monies was allocated to 

each county in an amount proportionate to its share of the total unincorporated population of all 

the counties. A similar distribution process was used for local governments. A total of $2.1 

million was allocated for plan development; however, not all components of the plans address 

nonpoint source issues. 

The effect of planning programs depends on many variables, including implementation of 

programs and monitoring of conformance with conditions of development approval. 

3.3.5 Land or Development Rights Acquisition Practices 

An effective way to preserve land necessary for protecting the environmental integrity of an area 

is to acquire it outright or to limit development rights. Land conservation includes more than 

simply preserving land in its current state. It also means taking responsibility for restoration of 

areas of the property that might already have been affected by urban runoff. Stewardship 

activities for land conservation might include: 

— Resource monitoring 

— General maintenance 

— Control of exotic species 

— Installation of structural runoff management practices 

A government agency or a nonprofit organization, such as a land trust, often has a greater 

capacity to take on the responsibility of stewardship than do private owners. Consequently, many 

of the practices discussed below focus on how conservation lands, or at least property rights to 

those lands, can be transferred to such entities. In many instances, however, private owners 

successfully accomplish stewardship without any formal or binding relationship with a public or 

private conservation agency or organization. 

Several organizations provide educational materials and training to help landowners learn to 

manage conservation areas for the benefit of water quality, wildlife, and other purposes. For 

example, the Land Trust Alliance, an organization that “promotes voluntary land conservation 

and strengthens the land trust movement by providing the leadership, information, skills, and 

resources land trusts need to conserve land for the benefit of communities and natural systems,” 

has compiled a list of links to local land trust organizations. This list can be accessed at 

http://www.lta.org/resources/links (Land Trust Alliance, 2001). Other information on land 

conservation policy, news, success stories, training opportunities, and technical guidance is 

provided on the Land Trust Alliance’s Web site at http://www.lta.org. 

Additionally, The Conservation Fund Web site, at http://www.conservationfund.org, provides 

information on land acquisition, community initiatives, leadership training, and sustainable 

conservation solutions emphasizing the integration of economic and environmental goals. 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Another resource is the Natural Lands Trust whose Web site, at http://www.natlands.org, 

provides information and resources pertaining to land preservation and land use planning. 

The practices described below can be used to protect beneficial uses. 

3.3.5.1 Fee simple acquisition/conservation easements 

The most direct way to protect land for preservation purposes and associated nonpoint source 

control functions is fee simple acquisition, through either purchase or donation. Once a suitable 

area is identified for preservation, the area may be acquired along with the development rights. 

The more development rights that are associated with a piece of property, the more expensive it 

will be. Many state and local governments and private organizations have programs for 

purchasing land. 

Conservation easements are legal restrictions on the present and future use of land. For 

preservation purposes, the easement holder, who is usually not the owner of the property, is able 

to control the rights of the property when the landowner might adversely impact resources on the 

property. In effect, the property owner gives up development rights within the easement while 

retaining fee ownership of the property (Mantel et al., 1990; Barrett and Livermore, 1983). The 

agreement between the easement holder and property owner is permanent, legally enforceable, 

and not subject to alteration unless permission is received in writing by the easement holder and 

all other cosigners (Arendt, 1997). 

A conservation easement is a flexible tool that can be customized to set different levels of 

restrictions among different types of conservation areas in a parcel. In addition to protecting and 

maintaining environmental benefits in perpetuity, landowners who donate conservation 

easements to a government agency or nonprofit group typically realize substantial income, 

property, and estate tax benefits resulting from the charitable donations. Their property value 

might be lowered, however, because the development rights were removed. Consequently, tax 

and estate planning professionals need to be consulted when a conservation easement is being 

contemplated. 

As an alternative, agricultural and forestry easements are specific types of conservation 

easements that allow continued use of land as farms or forests and prevent the land from being 

sold for commercial or residential development. The USDA Natural Resource Conservation 

Service currently manages the Farm and Ranch Lands Protection Program (FRPP), a voluntary 

program that provides matching funds to state, tribal, or local governments and nongovernmental organizations with existing farm and ranch land protection programs to purchase 

conservation easements. FRPP is reauthorized in the Farm Security and Rural Investment Act of 

2002, also known as the Farm Bill (NRCS, 2003). 

3.3.5.2 Leases, deed restrictions, and covenants 

Even though government agencies, land trusts, and other nonprofit organizations would prefer 

that conservation lands be acquired by donation or that conservation easements be placed on the 

property, some lands hold so much value as conservation areas that leasing is worth the expense 

and effort. Leasing a property allows the agency, trust, or organization to actively manage the 

land for conservation. 

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Management Measure 3: Watershed Protection 

Deed restrictions are included in deeds for the purpose of constraining use of the land. In theory, 

deed restrictions are designed to perform functions similar to those of conservation easements. In 

practice, however, deed restrictions have proven to be much weaker substitutes because unlike 

conservation easements, they do not necessarily designate or convey oversight responsibilities to 

a particular agency or organization to enforce protection and maintenance provisions. Also, deed 

restrictions can be relatively easy to modify or vacate through litigation. Modifying or nullifying 

an easement is difficult, especially if tax benefits have already been realized. For these reasons, 

conservation easements are generally preferred over deed restrictions. 

A covenant is similar to a deed restriction in that it restricts activities on a property, but it is in 

the form of a contract between the landowner and another party. The term mutual covenants is 

used to describe a situation where one or more nearby or adjacent landowners are contracted and 

covered by the same restrictions. 

3.3.5.3 Transfer of development rights 

The principle of transfer of development rights (TDR) is based on the concept that ownership of 

real property includes the ownership of a bundle of rights that goes with it. These rights may 

include densities granted by a certain use designation, environmental permits, zoning approvals, 

and others. Certain properties have a bigger bundle of rights than others, depending on what 

approvals have been received by the owner. The TDR system takes all or some of the rights on 

one piece of property and moves them to another parcel. The purpose of TDRs is to shift future 

development potential from an area that is determined to be unsuitable for development (sending 

site) to an area deemed more suitable (receiving site). The development potential can be 

measured in a variety of ways, including number of dwelling units, square footage, acres, or 

number of parking spaces. Most TDR systems require a legal restriction for future development 

on the sending site. TDR programs can be either fixed so that there are only a certain number of 

sending and receiving sites in an area, or flexible so that a sender and receiver can be matched as 

the situation allows (Mantel et al., 1990; Barrett and Livermore, 1983). 

This system is useful for the preservation of those areas considered necessary for maintaining the 

quality of surface waters, in that development rights associated with the environmentally 

sensitive areas can be transferred to less-sensitive areas. There are several examples of TDR use 

in the United States. The more successful projects include preservation of the New Jersey Pine 

Barrens and the Santa Monica Mountains in California. For the TDR concept to work, receiving 

and sending sites should be identified and evaluated, a simple, flexible program should be 

developed, and the use of the program should be promoted and facilitated (Mantel et al., 1990). 

In contrast to a conventional down-zoning approach, which withholds from landowners the value 

associated with the right to develop, TDR systems allow a landowner to be compensated for that 

value by developing at another site. 

Most TDR systems require a legal restriction to ensure that future development will not occur on 

the “sending” site. Also, TDR programs can be fixed so that there are only a certain number of 

sending and receiving sites in an area, or they can be flexible so that a sender and receiver can be 

matched as the situation allows. The following are general steps for setting up a TDR program 

(Redman/Johnston Associates, 1997): 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

— Provide education and outreach. The public should be familiar with the overall 

objectives of the program. Landowners and developers also need to be educated on how 

they will be affected. 

— Conduct an analysis of market conditions. A successful program requires a market for 

TDR transfers. 

— Identify and designate TDR “receiving areas.” Receiving areas should be capable of 

supporting growth. Factors include adequate land area, infrastructure, public services, and 

consideration of environmental constraints. 

— Identify and designate TDR “sending areas.” Sending areas should support preservation 

and protection goals. Specific areas should be delineated to the parcel level. 

— Determine the nature of program. Programs can be voluntary or mandatory. If 

mandatory, sending areas should be down-zoned to control growth. 

— Determine development potential and allocate TDRs. Compute current allowable

densities in both receiving and sending areas, and then allocate TDRs from sending areas 

based on desired densities. For example, down-zoning from a yield of 1 lot per 5 acres to 

1 lot per 25 acres equates to 4 TDRs. 

— Consider a TDR Bank. A TDR bank buys, holds, and sells TDRs. The bank can be either 

a government organization or a quasi-governmental entity. 

Transfer of Development Credits Pilot Program, King County, Washington

King County, Washington’s Transfer of Development Credits (TDC) Pilot Program is a voluntary 

initiative that allows residential densities to be transferred from rural areas to urban areas better suited 

to absorb additional density (King County Office of Regional Policy and Planning, 2001). The following 

provisions were made: 

— A $1.5 million TDC bank was established to purchase and sell density credits. 

— $500,000 was appropriated for urban amenities to improve neighborhoods that will receive 

increased density. 

— An extensive outreach effort has been launched to inform stakeholders about the program and 

identify potential receiving sites. 

— The Rural Forest Commission has reviewed and approved sending site criteria to be used by 

the TDC bank. 

The first successful TDC was finalized in 2000 (Sims, 2000a). Forest land totaling 313 acres was 

protected from development. The density credits were transferred to a developer to add 500,000 

square feet of commercial space in the nearby city of Issaquah. 

More information about this TDC is presented at ww.metrokc.gov/exec/news/2000/032800.htm. More 

information about the King County TDC Pilot Program can be obtained from the program’s Web site at 

http://www.metrokc.gov/exec/orpp/tdc or by contacting Mark Sollitto at 206-205-0705. 

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Management Measure 3: Watershed Protection 

— Provide adequate resources. A TDR program does not run itself. It needs staff and 

resources to administer and manage the program. 

3.3.5.4 Purchase of development rights 

In this process, the rights of development are purchased while the remaining rights remain with 

the fee title holder. Restrictions in the deed make it clear that the land cannot be developed based 

on the rights that have been purchased (Mantel et al., 1990). 

Howard County, Maryland, has the goal of preserving 20,000 acres of farmland. Development 

rights are acquired in perpetuity with 1⁄4th of 1 percent of the local land transfer tax used as 

funding. There is no cap on the percentage of assessed value that may be considered 

development value, and payment for development rights may be spread over 30 years to ease the 

capital gains tax burden on the landowner (Jenkins, 1991). 

3.3.5.5 Land trusts 

Land trusts may be established as publicly or privately sponsored nonprofit organizations with 

the goal of holding lands or conservation easements for the protection of habitat, water quality, 

recreation, or scenic value, or for agricultural preservation. A land trust may also pre-acquire 

properties that are conservation priorities if it enters the development market when government 

funds are not immediately available by securing bank funding with the government as guarantor 

(Jenkins, 1991). 

3.3.5.6 Agricultural and forest districts 

Agricultural or forest districting is an alternative to acquisition of land or development rights. 

Jurisdictions may choose to allow landowners to apply for designation of land as an agricultural 

or forest district. Tax benefits are received in exchange for a commitment to maintain the land in 

agriculture, forest, or open space. 

Fairfax County, Virginia, taxes land designated as an agricultural or forest district based on the 

present use valuation rather than the usual potential use valuation. A commitment to agricultural 

or forestry activities must be shown, and sound land management practices must be used. The 

districts are established and renewed for eight-year periods (Jenkins, 1991). 

3.3.5.7 Cost and effectiveness of land acquisition programs 

The costs associated with land acquisition programs vary depending on the desired outcome. If 

land is to be purchased, the cost depend on the value of the land. An additional cost to be 

considered is the maintenance of the property once it is in public ownership. Easements and 

development rights are less expensive, and maintenance responsibility is retained by the owner. 

Depending on the size of the local government, implementation of these programs is usually part 

of the operating budget of the appropriate agency (planning department or parks and recreation 

department, for example). 

The effectiveness of a land acquisition program is determined by the size of the parcel and the 

difference between predevelopment and potential postdevelopment pollutant loading rates. In 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

addition, wetlands and riparian areas have been shown to reduce pollutant loadings. The 

acquisition and preservation of these areas can be extremely important to water quality 

protection and decrease the cost of implementing structural BMPs. However, the use of wetlands 

for urban runoff treatment, in general, should be discouraged. Where no other alternative exists, 

states and local governments can target upland areas for acquisition to minimize the impacts to 

and preserve the function of wetlands. One option for acquiring land is a public/private 

partnership. For example, Harford County, Maryland, has targeted areas for purchase of 

conservation easements. The county staff is working jointly with a local land trust to acquire 

conservation easements and to educate people in environmentally sound land-use practices. The 

estimated cost for the program is $60,000 per year (Jenkins, 1991). To aid in the establishment of 

two local land trusts, Anne Arundel County, Maryland, provided $350,000 in seed money for 

capital expenditures such as land and easement procurement. The county also gives staff 

assistance to volunteers; additional support comes from contributions of money or land, grants, 

and fundraisers (Jenkins 1991). 

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Management Measure 3: Watershed Protection 

3.4 Information Resources 

The Center for Watershed Protection’s Rapid Watershed Planning Handbook, published in 1998, 

describes techniques communities can use to more effectively protect and restore water 

resources. This document is available for purchase from the Center for Watershed Protection’s 

Web site (http://www.cwp.org). 

The Chesapeake Bay Program’s (1997) Protecting Wetlands: Tools for Local Governments in 

the Chesapeake Bay Region is available from the Chesapeake Bay Program’s Web site at 

http://www.chesapeakebay.net. 

The Conservation Fund’s Web site, located at http://www.conservationfund.org, provides 

information on land acquisition, community initiatives, leadership training, and sustainable 

conservation solutions emphasizing the integration of economic and environmental goals. 

Correll’s (2000) Web site, entitled Vegetated Stream Riparian Zones: Their Effects on Stream 

Nutrients, Sediments, and Toxic Substances, presents an annotated and indexed bibliography of 

buffer strip literature. See http://www.unl.edu/nac/ripzone03.htm. 

Eco-Compass (Island Press, 2000) is an information resource for urban sprawl issues. Developed 

by Island Press, Eco-Compass is an Internet guide to a wide range of environmental information, 

including ecosystems, communities, global change, and economics. The urban sprawl feature of 

Eco-Compass provides a summary of the major issues relating to sprawl as well as an 

examination of the lessons that can be learned from Atlanta, a city that has experienced 

tremendous growth in the past decade. The site also includes links to more than 50 of the best 

sprawl-related Web sites and publications. More information about Eco-Compass is available at 

http://www.islandpress.org/. 

The Natural Lands Trust’s 1997 publication, Growing Greener: Putting Conservation into Local 

Codes, is available from Natural Land Trust, 1031 Palmers Mill Road, Media, PA 19063; 

telephone 610-353-5587; e-mail planning@natlands.org. Other information and resources 

pertaining to land preservation and land use planning can be found at the Natural Lands Trust’s 

Web site at http://www.natlands.org. 

Schueler’s (1995) manual, Site Planning for Urban Stream Protection, is available for download 

from the Center for Watershed Protection’s Web site at http://www.cwp.org/SPSP/TOC.htm. 

Based on the Local Government Commission's research of more than 150 “smart growth” zoning 

codes from across the nation, Smart Growth Zoning Codes: A Resource Guide will help planners 

design a zoning code that encourages the construction of walkable, mixed use neighborhoods and 

the revitalization of existing places. Each chapter analyzes a critical issue, such as design, streets, 

and parking, and highlights exemplary codes from across the country. The guidebook comes 

with a CD-ROM that contains copies of some of the best zoning codes in the United States and 

other resources. The guide is available for purchase ($25) from the LGC bookstore at 

http://www2.lgc.org/bookstore/detail.cfm?itemId=34. 

 3-29 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

The Smart Growth Network is a nationwide effort coordinated by EPA’s Urban and Economic 

Development Division (International City/County Management Association, 2000). Through 

cooperative partnerships with a diverse network of organizations, EPA is working to encourage 

development that better serves the economic, environmental, and social needs of communities. 

The network provides a forum for information sharing, education, tool development and 

application, and collaboration on smart growth issues. Smart growth approaches focus on 

flexible zoning, preventive planning, intelligent management of natural resources and water 

quality, and implementation of treatment and control technologies at multiple scales from 

development sites to watershed planning. For more information about the Smart Growth 

Network, visit http://www.smartgrowth.org or contact ICMA—Smart Growth Network, 777 

North Capitol St., NE, Suite 500, Washington, DC 20002-4201; telephone 202-962-3591; e-mail 

nsimon@icma.org. 

The Mid-America Regional Council (MARC) initiated a project to raise awareness of the 

relationship between land development and transportation systems. In Principles of Transit 

Supportive Development, MARC (no date) presents alternative approaches to land development 

that encourage a more sustainable and balanced transportation system. The organization 

promotes community designs that enable citizens to walk, bike, ride transit, and drive from home 

to shops, schools, and services. For more information about the potential of transit supportive 

development, contact MARC at 816-474-4240 or visit their Web site at 

http://www.marc.org/transportation. 

The Local Government Commission (http://www.lgc.org) is a nonprofit organization that 

provides peer networking opportunities, acts as an interface between city and county officials, 

and provides practical policy ideas for addressing serious environmental and social problems. 

The commission provides guidelines and resources for communities to improve their design, 

transportation, economic development, environment, energy, and waste prevention. A list of 

publications can be found at http://www2.lgc.org/bookstore/list.cfm?categoryId=1. 

The Northeastern Illinois Planning Commission published Model Stream and Wetland Protection 

Ordinance for the Creation of a Lowland Conservancy Overlay District: A Guide for Local 

Officials, which can be ordered from its Web site at http://www.nipc.org/pubs-services/. 

The National Association of Conservation Districts’ Web site (http://www.nacdnet.org) contains 

a list of conservation districts across the country as well as conservation resources for districts, 

educators, and the public. 

In July 2001 the National Governors’ Association Center for Best Practices published New 

Community Design to the Rescue: Fulfilling Another American Dream (Hirschhorn and Souza, 

2001), which provides alternatives to sprawl through “new community design.” The book 

includes a checklist for local governments to evaluate communities and development projects for 

consistency with smart growth principles and provides examples of infill, suburban 

redevelopment, and greenfields projects that have successfully incorporated new community 

design principles. Innovative policies and actions taken by states to encourage new community 

design are also included. This publication can be purchased at the National Governors’ 

Association Web site at http://www.nga.org or downloaded in PDF format at 

http://www.nga.org/cda/files/072001NCDFull.pdf. 

3-30 
Management Measure 3: Watershed Protection 

“Protecting Water Resources with Smart Growth” is intended for audiences such as 

communities, local governments, state and regional planners already familiar with smart growth 

who are now seeking additional ideas on how to protect their water resources. The document is a 

compilation of 75 policies designed to protect water resources and implement smart growth. The 

majority of these policies (46) are oriented to the watershed, or regional level; the other 29 are 

targeted for specific development sites. The document is available for download in PDF format 

at http://www.epa.gov/smartgrowth/water_resource.htm. 

Getting to Smart Growth: 100 Policies for Implementation was produced by the Smart Growth 

Network. The document highlights and describes techniques to help policymakers put smart 

growth principles into practice. The policies and guidelines, which have proven successful in 

communities across the U.S., range from formal legislative or regulatory efforts to informal 

approaches, plans, and programs. The primer describes 10 smart growth principles, specific 

policies for each principle, illustrations of their application in a community, and additional 

resources to aid communities in implementation. The document is available online in PDF 

format at http://www.smartgrowth.org/pdf/gettosg.pdf. 

The concept of creating and maintaining an interconnected network of protected land and water, 

called “Green Infrastructure,” is presented at http://www.greeninfrastructure.net. Green 

Infrastructure supports native species, maintains natural ecological processes, sustains air and 

water resources, and contributes to health and quality of life. This Web site, developed by The 

Conservation Fund with support from USDA Cooperative Forestry, contains information to aid 

in implementing a comprehensive conservation program and includes resources such as 

searchable profiles, training information, events, and references databases. 

The Southeast Michigan Council of Governments (SEMCOG) published Opportunities for 

Water Resource Protection in Local Plans, Ordinances and Programs: A Workbook for Local 

Governments, which is a guide for local communities to protect water resources. The workbook 

provides checklists that guide users through the process of establishing a water resource 

protection program. It covers a wide range of topics, including land conservation, erosion and 

sediment control, public education, and pollution prevention. For each of these topics, case 

studies and checklists guide users through basic tools available for master planning, regulatory 

controls, and design standards. The document can be downloaded from http://www.semcog.org

or ordered by calling 313-961-4266. 

EPA’s Green Communities Program encourages successful community-based environmental 

protection and sustainable community development. The Green Communities Assistance Kit 

provides technical assistance and training for planning green communities. Information about the 

Green Communities Program can be found at http://www.epa.gov/greenkit. 

Other useful EPA publications: 

U.S. Environmental Protection Agency (USEPA). 1996. Green Development: Literature 

Summary and Benefits Associated with Alternative Development Approaches. EPA841-

B-97-001. U.S. Environmental Protection Agency, Washington, DC. Available through 

EPA’s National Service Center for Environmental Publications (NSCEP) at 

http://www.epa.gov/ncepihom or by calling 800-490-9198. 

 3-31 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

U.S. Environmental Protection Agency ( USEPA). 1998. The Volunteer Monitor. U.S. 

Environmental Protection Agency, Washington DC. Available in HTML format at 

http://www.epa.gov/owow/monitoring/volunteer/vm_index.html. 

U.S. Environmental Protection Agency (USEPA). 1999. Model Ordinances to Protect 

Local Resources. U.S. Environmental Protection Agency, Washington DC. Available in 

HTML format at http://www.epa.gov/owow/nps/ordinance. 

U.S. Environmental Protection Agency (USEPA). 2001. Monitoring Water Quality: 

Volunteer Monitoring. U.S. Environmental Protection Agency, Washington DC. 

Available in HTML format at http://www.epa.gov/volunteer. 

3-32 
Management Measure 3: Watershed Protection 

3.5 References 

Arendt, R.G. 1997. Growing Greener: Putting Conservation into Local Codes. Natural Lands 

Trust, Inc., Media, PA. 

Barrett, T.S., and P. Livermore. 1983. The Conservation Easement in California. Island Press, 

Covelo, CA. 

Broward County, Florida. 1990. Land Development Code. Ft. Lauderdale, FL. 

Caraco, D., R. Claytor, P. Hinkle, H.Y. Kwon, T. Schueler, C. Swann, S. Vysotsky, and J. 

Zielinski. 1998. Rapid Watershed Planning Handbook. Center for Watershed Protection, 

Ellicott City, MD. 

City of Tucson. No date. Summary of Growing Smarter and Growing Smarter Plus Legislation. 

http://www.ci.tucson.az.us/planning/grosmart/gsovervu.pdf. Accessed August 21, 2003. 

Correll, D. 2000. Vegetated Stream Riparian Zones: Their Effects on Stream Nutrients, 

Sediments, and Toxic Substances. http://www.unl.edu/nac/ripzone03.htm. Last updated 

September 2001. Accessed May 28, 2002. 

Critical Area Commission for the Chesapeake and Atlantic Coastal Bays. No date. Frequently 

Asked Questions. http://www.dnr.state.md.us/criticalarea/faq.html#14. Accessed March 

3, 2005. 

Delaware County Departments of Planning and Public Works. 2003. Stormwater Management: 

Delaware County Action Plan. Version 1. 

Dunn, T., and L.B. Leopold. 1978. Water in Environmental Planning. W.H. Freeman and 

Company, San Francisco, CA. 

Environmental News Network (ENN). 2001, January 10. Calculating the Benefits of Houston’s 

Urban Trees. http://www.dnr.state.md.us/criticalarea/faq.html. Last updated January 10, 

2001. Accessed April 6, 2001. 

Herson-Jones, L.M., M. Hearty, and B. Jordan. 1995. Riparian Buffer Strategies for Urban 

Watersheds. Metropolitan Washington Council of Governments, Washington, DC. 

Hirschhorn, J.S., and P. Souza. 2001. New Community Design to the Rescue: Fulfilling Another 

American Dream. National Governors’ Association, Washington, DC. 

Holler, S. 1989. Buffer Strips in Watershed Management. In Watershed Management Strategies 

for New Jersey, Cook College Department of Environmental Resources and New Jersey 

Agricultural Experiment Station, Rutgers University, New Brunswick, NJ, pp. 69–116. 

Honeczy, M.R. 2000. The Maryland Forest Conservation Act—A 5-Year Review. Presented at 

the 2000 APA National Planning Conference, New York, New York, April 16, 2000. 

 3-33 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

http://www.asu.edu/caed/proceedings00/FOREST3/honeczy.htm. Accessed March 3, 

2005. 

International City/County Management Association. 1979. The Practice of Local Government 

Planning. American Planning Association, Chicago, IL. 

International City/County Management Association. 2000. Smart Growth Network. 

www.smartgrowth.org. Last updated June 17, 2000. Accessed June 21, 2000. 

Island Press. 2000. Eco-Compass: Sprawl Cities. www.islandpress.org/ecocompass/ 

community/sprawl.html. Accessed April 4, 2001. 

Jenkins. 1991. Chesapeake Bay Restoration: Innovations at the Local Level. A Compilation of 

Local Government Programs. The Chesapeake Bay Local Government Advisory 

Committee and the U.S. Environmental Protection Agency, Annapolis, MD. 

King County Office of Regional Policy and Planning. 2001. Transfer of Development Credits 

(TDC) Program. Last updated April 23, 2001. Accessed May 1, 2001. 

Land Trust Alliance. 2001. Links to Web Sites of Sponsor Members of the Land Trust Alliance. 

www.lta.org/resources/links. Last updated February 16, 2001. Accessed May 1, 2001 

Livingston, E.H., and E. McCarron. 1992. Stormwater Management: A Guide for Floridians. 

Florida Department of Environmental Regulation, Tallahassee, FL. 

Mantel, M.A., S.F. Harper, and L. Propst. 1990. Creating Successful Communities: A Guidebook 

to Growth Management Strategies. Island Press, Washington, DC. 

Maryland Department of Planning. No date. The Economic Growth, Resource Protection, and 

Planning Act of 1992. http://www.mdp.state.md.us/planningact.htm. Accessed March 3, 

2005. 

Maryland Environmental Trust Land Conservation Center. 2002. Local County Purchase of 

Development Rights (PDR) Programs. http://www.conservemd.org/purchased/pdr. 

Accessed March 3, 2005. 

Meeks, G. 1990. State Land Conservation and Growth Management Policy: A Legislator’s 

Guide. National Conference of State Legislators, Washington, DC. 

Metro-Dade Planning Department. 1988. Comprehensive Development Master Plan. Miami, FL. 

Michigan Department of Environmental Quality. No date. Into Every Life a Little Rain Must 

Fall. Michigan Department of Environmental Quality, Madison, WI. 

Mid-America Regional Council (MARC). No date. Principles of Transit Supportive 

Development. Mid-America Regional Council, Kansas City, MO. 

3-34 
Management Measure 3: Watershed Protection 

Morrison, M. 2000, June 5. A sudden oasis, or just sprawl? Phoenix exurb sharpens growth 

debate. The Washington Post, p. A3. 

National Association of Local Government Environmental Professionals (NALGEP). 2003. 

Smart Growth for Clean Water: Helping Communities Address the Water Quality 

Impacts of Sprawl. National Association of Local Government Environmental 

Professionals, Trust for Public Land, ERG. 

http://www.resourcesaver.com/file/toolmanager/CustomO93C337F42157.pdf. Accessed 

June 30, 2003. 

National Park Service (NPS). 2001. Colonial National Historical Park. 

http://www.nps.gov/colo/. Last updated May 2, 2001. Accessed May 2, 2001. 

Natural Resource Conservation Service (NRCS). 2003. Farm Bill 2002: Farm and Ranch Lands 

Protection Program. Natural Resource Conservation Service, U.S. Department of 

Agriculture. http://www.nrcs.usda.gov/programs/farmbill/2002/pdf/FRPPFct.pdf. 

Nelson, A.C. and T. Moore. 1993. Assessing urban growth management: The case of Portland, 

Oregon, the USA’s largest urban growth boundary. Land Use Policy 10(4): 293-302. 

Price, J. 2000, December 7. Apex leaders agree to beef up their stream-protection measures: New 

rules call for larger buffers. The Raleigh News and Observer. 

Redman/Johnson Associates. 1997. Beyond Sprawl—Land Management Techniques for the 

Chesapeake Bay: A Handbook for Local Governments. EPA 903-B-97-005. U.S. 

Environmental Protection Agency, Region 3, Chesapeake Bay Program Office, 

Annapolis, MD. 

Schueler, T. 1995. Site Planning for Urban Stream Protection. Metropolitan Washington 

Council of Governments, Washington, DC. 

Simmons, M.M. 1991. Coastal Barriers Protection Issues in the 101st Congress. Congressional 

Reporting Service, Environment and Natural Resource Policy Division, Washington, DC. 

Sims, R. 2000a. First Transfer of Development Credits in NW Celebrated. www.metrokc.gov/ 

exec/news/2000/032800.htm. Last updated March 28, 2000. Accessed May 4, 2001. 

Sims, R. 2000b. SmartGrowth: Rural Legacy. www.metrokc.gov/smartgrowth/rural.htm. Last 

updated May 31, 2000. Accessed May 1, 2001. 

Stapleton, B. 1999. Old B/A Gas Station Finds New Life. 

http://www.oldgas.com/info/banewtonville.html. Last updated September 11, 1999. 

Accessed February 21, 2000. 

Tritto, C. 2000, November 13. City seeks policy on storm water. Missourian, p. 9. 

 3-35 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

U.S. Department of Agriculture, Natural Resources Conservation Service (USDA-NRCS). 2000. 

1997 National Resources Inventory. 

http://www.nrcs.usda.gov/technical/NRI/1997/index.html. Accessed June 5, 2000. 

U.S. Environmental Protection Agency (USEPA). 1992. Notes of Riparian and Forestry 

Management. In U.S. EPA, Nonpoint Source News Notes. U.S. Environmental Protection 

Agency, Office of Water, Washington, DC. March 1992, pp. 10–11. 

U.S. Fish and Wildlife Service. 2002. The Coastal Barrier Resources Act: Harnessing the Power 

of Market Forces to Conserve America’s Coasts and Save Taxpayers’ Money. 

http://www.fws.gov/habitatconservation/TaxpayerSavingsfromCBRA.pdf. Last updated 

August 2002. Accessed March 3, 2005. 

University of Oregon. 1995. What is an Urban Growth Boundary? darkwing.uoregon.edu/ 

~pppm/landuse/UGB.html. Last updated May 10, 1995. Accessed April 5, 2001. 

Verden, T. 2000, September 25. Officials sign pact to balance development with preservation. 

The Sacramento Bee, p. N10. 

3-36 
Management Measure 4: Site Development 

MANAGEMENT MEASURE 4 

SITE DEVELOPMENT 

4.1 Management Measure 

Plan, design, and develop sites to: 

— Maintain predevelopment site hydrology by using site design techniques that store, 

infiltrate, evaporate, or detain runoff; 

— Protect areas that provide important water quality benefits or are particularly susceptible 

to erosion and sediment loss; 

— Limit effective impervious areaa by design and the use of management practices; 

— Limit land disturbance activities, such as clearing and grading and cut-and-fill, to reduce 

erosion, sediment loss, and soil compaction; and 

— Preserve natural drainage features and vegetation to the extent possible. 

4.2 Management Measure Description and Selection 

4.2.1 Description 

The goals of this management measure are to reduce the generation of nonpoint source pollution, 

maintain predevelopment hydrology, and mitigate the impacts of urban runoff and associated 

pollutants from all site development, including activities associated with roads, highways, and 

bridges. Included in this section are management practices that can be applied during the site 

planning and review process to ensure that nonpoint source pollution and increases in the volume 

and rate of runoff are appropriately managed before, during, and after construction. 

Although the goals of Management Measure 3 (watershed protection) are similar, this measure is 

intended to apply to individual sites at the catchment level (see Figure 1.3) rather than larger 

watersheds or regional drainage basins. The site development and watershed protection 

management measures are intended to complement each other and be used together within a 

comprehensive framework to control runoff and reduce nonpoint source pollution. 

 

a

 Effective impervious area is the portion of total impervious cover that is directly connected to the storm drain 

network (Sutherland, 1995). These surfaces usually include street surfaces and paved driveways and sidewalks 

connected to or immediately adjacent to them, parking lots, and rooftops that are hydraulically connected to the 

drainage network (e.g., downspouts run directly to gutters or driveways). 

4-1 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Programs designed to control increased runoff and nonpoint source pollution resulting from site 

development should include: 

— Predevelopment planning and review processes to ensure watershed/subwatershed and 

site-level natural resource and performance goals are achieved; 

— Guidance on assessing and designing sites to maintain predevelopment site hydrology; 

— Appropriate pollution prevention practices to be incorporated into site development and 

use. 

— Site plan review and conditional approval processes to ensure the preservation of 

environmentally sensitive areas and areas necessary for maintaining natural hydrology 

and water quality; and 

— Requirements for erosion and sediment control plan review and approval prior to 

issuance of appropriate development permits. 

In addition to the preceding provisions, the following objectives should be incorporated into the 

site development process: 

— During site development, disturb only the smallest area necessary to perform current 

activities to reduce erosion and off-site transport of sediment. 

— Avoid disturbance of unstable soils or soils particularly susceptible to erosion and 

sediment loss. 

— Favor sites where development will conserve natural drainage areas and sensitive 

environmental features, and minimize erosion, sediment loss, and soil compaction. 

— Revegetate the site as soon as possible after disturbance, preferably with native 

vegetation. 

— Protect and retain existing vegetation to decrease concentrated flows, maintain site 

hydrology, and control erosion. 

— Minimize imperviousness to the extent practicable. 

— Develop and implement inspection and maintenance procedures to ensure that landscapes 

are maintained to avoid water quality impacts. 

— Use natural hydrology as a design element, and avoid alteration, modification, or 

destruction of natural drainage features. 

— Design sites to preserve vegetated or natural buffers adjacent to receiving waters. 

4-2 
Management Measure 4: Site Development 

— Reforest areas within the same watershed in proportion to the acreage cleared of trees. 

— Use porous pavements for areas of infrequent use (see section 5.3.2.3 in Management 

Measure 5). 

The use of site planning and evaluation can significantly reduce the size of controls required to 

retain runoff and sediment on-site. Long-term maintenance burdens can also be reduced. Good 

site planning can attenuate runoff from development and can improve the effectiveness of the 

conveyance and treatment components of an urban runoff management system (Anacostia 

Restoration Team, 1992). 

4.2.2 Management Measure Selection 

This management measure was selected because the practices associated with it have been 

shown to be effective in protecting natural drainage features, reducing runoff quantity, and 

improving runoff quality. Site evaluation and protection of features that promote infiltration, 

filtration, and on-site detention will protect receiving water quality, maintain baseflow in 

receiving waters, and prevent or reduce further degradation of stream channels. Development in 

and around urban areas is inevitable as population growth puts pressure on suburbs and rural 

areas. This management measure recommends standards for new development that reduce 

environmental damage caused by development. 

4.3 Management Practices 

Many of the management practices in this section are considered “better site design techniques,” 

planning techniques that are intended to be used to guide the layout of new developments to 

reduce the total effective impervious area, conserve natural habitats, and better distribute and 

infiltrate runoff. All aspects of an individual site, including soil types, slopes, and the location of 

environmentally sensitive features such as wetlands, forests, and meadows, should be examined 

to identify areas that should be preserved or restored. Better site design techniques can be used to 

identify the most efficient building and infrastructure layouts. It can also be used to develop a 

comprehensive strategy to reduce the quantity of runoff leaving the site and minimize the amount 

of pollutants generated on-site. 

There are many advantages to better site design. Environmentally friendly site designs are more 

likely to be accepted by local governments and the community, thereby speeding plan approval. 

Site designs that preserve community open space also reduce the burden on the local government 

to provide recreational areas. In addition, better site design techniques reduce the amount and 

cost of infrastructure, which also in turn reduce engineering and maintenance costs. For example, 

runoff storage requirements for a low-impact development neighborhood in Pierce County, 

Washington, were reduced by more than 75 percent and the cost was 20 percent less than for 

conventional designs. These cost savings resulted primarily from the reduced size of runoff 

detention structures and the elimination of catch basins and pipes (Zickler, 2002). 

Low-impact development practices can provide substantial benefits in terms of reducing the 

occurrence of combined sewer overflows (CSOs). Temporarily storing runoff in urban areas can 

greatly reduce the peak flow into storm water systems and provide a cost-effective way to 

4-3 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

mitigate basement flooding and CSOs (USEPA, 1999). Two communities in Indiana successfully 

implemented street surface storage of runoff to reduce the occurrence of CSOs in a cost effective 

manner while also reducing peak flows to wastewater treatment plants. The distributed storage 

controls also offered some water quality benefits by temporarily detaining runoff during storms 

(USEPA, 1999). 

From a marketing perspective, studies have shown that lots abutting forested or other open space 

are initially valued higher than lots with no adjacent open space, and over time they appreciate 

more than lots in conventional subdivisions (Arendt, 1996). For example, lots in an open space 

subdivision in Amherst, Massachusetts, experienced a 13 percent greater appreciation in value 

compared to a conventional development after 20 years, even though the lots in the conventional 

development were twice as large (Arendt, 1996). 

From a quality-of-life standpoint, site designs that incorporate pedestrian paths and common 

open space foster a greater sense of community among residents. House lots are closer together, 

encouraging communication among neighbors. Additionally, common open space provides 

recreational opportunities that further encourage community interaction. 

Finally, better site design offers environmental benefits, including protection of ecologically 

significant natural resources, reduction of runoff, and preservation of open space and wildlife 

habitat. Maintaining open space also increases the opportunity for alternative sewage and 

wastewater disposal and treatment practices such as land treatment, spray irrigation, and 

reclamation and reuse. In addition, the flexibility of better site design allows designers to site 

these wastewater treatment systems in the areas of the development best suited for them. 

Overall, the practices presented in this management measure provide many advantages over 

conventional developments and can be implemented in most communities. In some cases, 

however, outdated development rules can discourage or prohibit some of these practices. 

Watershed managers should review the local building codes and regulations that govern new 

developments to determine whether better site design techniques are allowed or encouraged and 

work with the appropriate authorities to remove these impediments. 

The second edition of the Bay Area Stormwater Management Agencies Association’s Start at the 

Source, which was originally published in 1997, is an excellent resource on site design issues for 

watershed managers. This publication emphasizes the importance of considering runoff quality 

in the early stages of land planning and design. The new edition has been updated and expanded 

to include commercial, industrial, and institutional development, as well as a technical section 

that provides more detailed information on the characteristics, applications, design criteria, 

maintenance, and economics of the practices discussed in the document. More information about 

ordering this publication when it becomes available is provided on the Bay Area Stormwater 

Management Agencies Association’s Web site at http://www.basmaa.org/ (BASMAA, no date). 

4-4 
Management Measure 4: Site Development 

Pembroke Woods Subdivision, Emmittsburg, Maryland

Pembroke Woods is a 43-acre low impact development residential subdivision that the designers hail 

as the first subdivision designed and under construction using the Low-Impact Development Design 

Strategies: An Integrated Design Approach manual developed by Prince George's County, Maryland 

(2000a). The designers have identified significant cost savings for this development compared to the 

traditional development plan created in the 1990s. These include 

— Eliminating the need for 2 storm water management ponds that had been envisioned in a prior 

concept plan for the site, yielding construction cost savings of $200,000. 

— In place of those 2 storm water management ponds, 2.5 acres of undisturbed open space and 

wetlands were conserved, with cost savings realized in eliminating wetland mitigation costs. 

— An additional 2 lots were created by revising the site plan, increasing the site yield from 68 to 

70 lots and adding $90,000 to the project value. 

— Approximately 3,000 linear feet of roads were converted from urban road to rural road, 

replacing curb & gutter with grass bioswales, yielding a savings of $60,000 in construction 

costs. Also, reducing the road with from 36 feet to 30 feet in the rural road section of the 

development reduced paving costs by 17 percent. 

A brief project overview and contact information can be found at 

http://www.buckeyedevelopment.net/lowimpactdevelopment.htm. 

4.3.1 Site Planning Practices 

4.3.1.1 Select site designs that preserve or minimize impacts to predevelopment site 

hydrology and topography 

Retaining the existing topography of a development site assists in maintaining natural drainage 

features and depressional storage areas that help infiltrate and attenuate flows and filter 

pollutants. Depressional storage areas, commonly found as ponded areas after storms or during 

the wet season, aid in reducing runoff volumes and trapping pollutants. To help preserve natural 

drainage, a developer can (Goldman et al., 1986): 

— Construct buildings and parking areas on existing flat terrain; 

— Locate buildings and roads along existing contours; 

— Orient long buildings with the major portion parallel to contours; 

— Stagger floor levels to adjust to gradient changes; and 

— Fit the development to the topography. 

4.3.1.2 Protect environmentally sensitive areas 

Sites should be developed to avoid destroying wetlands, seeps, bogs, fens, springs, surface water 

bodies, and catchment areas that are important for sustaining the hydrology of the land. In 

addition, riparian buffers, both forested and covered with grasses, should be preserved to protect 

4-5 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

surface water bodies. Steep slopes and highly erodible areas need to be protected to avoid 

landslides and soil movement into water bodies. 

The increase in storm water runoff that results from urban development can dramatically impact 

the ecology of wetlands and other areas by altering characteristics of hydrology, water quality, 

and soil (USEPA, 1996). Urban development can also result in ecological changes due to 

fragmentation and habitat destruction. If the development of a site changes runoff characteristics, 

measures should be taken to prevent negative impacts to wetlands and other features. For 

example, Pohlig Builders of Malvern, Pennsylvania, incorporated measures to protect wetlands 

into its building plan after homeowners opposed the construction of seven high-end homes 

adjacent to a wetland area. Pohlig designed a vegetative filter strip to buffer runoff from the 

homes and provide treatment before runoff reached the wetlands. The filter strip was designed to 

eventually grow into a wooded area to enhance aesthetics and benefit water quality. A level 

spreader was added to convert concentrated runoff to sheet flow that can be more effectively 

treated, and extra erosion and sediment control measures were used during construction. The 

total additional cost of these measures was $30,000 (NAHB, 2003). 

4.3.1.3 Practice site fingerprinting 

The total amount of disturbed area in a site can be reduced by “fingerprinting” development, i.e., 

placing development in the most environmentally sound locations on the site and minimizing the 

size of the disturbed area and ultimate development footprint. Fingerprinting places development 

away from environmentally sensitive areas (wetlands, steep slopes, etc.), future open spaces and 

restoration areas, areas with trees to be saved, and temporary and permanent vegetative forest 

buffer zones. At a subdivision or lot level, ground disturbance is confined to areas where 

structures, roads, and rights-of-way will exist after construction is complete. Other site-level 

fingerprinting practices include reducing paving and compaction of highly permeable soils, 

minimizing the size of construction easements and material storage areas, minimizing 

impervious areas in the site design, clearly demarcating the disturbance area, maintaining 

existing topography and drainage divide, and disconnecting impervious areas (Prince George’s 

County, Maryland, Department of Environmental Resources, 2000a). 

4.3.1.4 Use cluster development 

Cluster development is used to concentrate development and construction activity on a limited 

portion of a site, leaving the remainder undisturbed. Figures 4.1 and 4.2 show schematics of a 

residential cluster development and a rural cluster development. Clustering allows the design of 

more effective urban runoff management systems and reduces overall site-level erosion and 

sediment impacts. It also provides a mechanism to preserve environmentally sensitive areas and 

reduce infrastructure such as wastewater treatment systems, roads, sidewalks, and parking areas. 

In addition to its environmental benefits, clustering can result in cost savings for municipalities 

because clustering and infill development typically require less new infrastructure, such as urban 

runoff treatment systems. The imposition of density controls may preclude clustering. Although 

minimum lot size requirements are useful in some instances, such as farmland preservation (see 

4-6 
Management Measure 4: Site Development 

Management Measure 3), zoning ordinances should not preclude the implementation of clustered 

development as an alternative to conventional suburban development. 

Figure 4.1: Schematic of a residential cluster development (Schueler, 1995).

Figure 4.2: Schematic of a rural cluster development (Schueler, 1995).

4-7 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

4.3.1.5 Create open space 

Open space development is a technique that concentrates development on one area of a site in 

exchange for open space in another area. Benefits associated with open space design include: 

— A 40- to 60-percent reduction in impervious cover compared to conventional 

development designs; 

— Increased property values; 

— Reduced construction and development costs; 

— Common recreational facilities (i.e., pedestrian paths, picnic areas, and athletic fields); 

— Reduced infrastructure; 

— Improved quality of life; and 

— The use of community onsite/decentralized systems (see Nutrient Export case study 

below). 

The following are some techniques for conserving open space: 

— By-right open space development. This technique allows increased density on one portion 

of a site in exchange for open space on another portion. A large percentage of this open 

space can be dedicated as conservation land. To encourage open space development, 

municipalities can draft ordinances so that this is a “by-right” option, as opposed to a 

special exception or variance. 

— Density compensation. This technique allows developers to increase housing density to 

offset potential housing lots lost to on-site buffers or other conservation lands. 

— Storm water credits. Credit is given for implementation of source controls that reduce 

runoff volumes and pollutant concentrations before the remaining runoff reaches 

structural controls. Because performance is typically measured by comparing influent 

runoff to effluent runoff, storm water credits benefit operators of structural controls 

because credit for pollutant removal occurs before treatment. 

— Property tax credit. The property tax credit is a technique for reducing, deferring, or 

exempting property taxes on conservation land. Typically, conservation easements are 

exchanged for the property tax credit.

— Density bonus. This bonus allows developers to increase density above base zoning 

density in exchange for conserving natural areas. 

— Off-site mitigation. This term refers to the restoration or creation of wetlands in a 

designated off-site area if on-site wetlands are adversely affected and on-site mitigation is 

not feasible. 

4-8 
Management Measure 4: Site Development 

Randall Arendt (1996), in his book, Conservation Design for Subdivisions: A Practical Guide for 

Creating Open Space Networks, presents a plain-language, illustrated guide for designing open 

space subdivisions. This publication is available from Natural Lands Trust, Inc., 1031 Palmers 

Mill Road, Media, PA 19063; phone 610-353-5587. The following topics are covered: 

— Open space vs. conventional developments; 

— Economic, social, and environmental benefits of open space designs; 

— Roles and responsibilities of stakeholders in site development; 

— A stepwise approach to designing an open space subdivision (discussed below); 

— Ideas for creating an interconnected open space network; 

— Seven case studies; 

— Methods to modify existing regulations to encourage open space design; 

— Management techniques for conservation lands; 

— Sample house plans for open space subdivisions; 

— Sample advertisements for developers to capitalize on open space design benefits; and 

— Model ordinance provisions. 

Arendt’s multi-step process for creating conservation subdivisions involves two stages. The first, 

called the background stage, involves identifying the characteristics of the surrounding landscape 

and existing development and analyzing and delineating significant features of the site. The 

second stage involves integrating the site’s feature information into a map and prioritizing 

conservation lands based on the features deemed most important, while maintaining the quantity 

of land necessary to develop the site to the desired density. 

The background stage involves examining the surrounding landscape and existing development 

to identify conservation areas. It includes the following practices: 

(1) Understanding the locational context. The layout of new development should consider 

proximity to traditional small towns or villages; if existing development is nearby, the design 

of the new community should reflect and extend the historical streetscape and pattern. In 

rural areas located away from existing development, informal, irregular, “organic” layouts 

can be used successfully without detracting from the surrounding landscape. 

(2) Mapping natural, cultural, and historic features. A thorough analysis of a site’s special 

features that may enhance or constrain development is an important step in planning a new 

development. Special features might already have been identified in a natural resources 

inventory conducted by local government or land trust organizations. The site analysis should 

include site visits and identify the conservation areas described in this section. 

The following conservation areas are legally or logistically unbuildable and therefore must be 

avoided: 

— Wetlands. Tidal and non-tidal saltwater and freshwater wetlands and the dry upland 

buffers surrounding them should be identified as areas to be conserved because they 

filter runoff, provide critical habitat at the land-water interface, and offer 

opportunities for recreation and environmental education. Soil survey maps, National 

4-9 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Wetlands Inventory maps, state or environmental agency wetland maps, or on-site 

delineations can be used to determine the extent of wetland habitat on the site. 

— Floodplains. The 100-year floodplain, which can be determined from floodplain maps 

published by the Federal Emergency Management Agency (FEMA) (see 

Management Measure 2), should be left undeveloped to preserve a continuous 

riparian greenway and to prevent damage to property from flooding. To preserve 

views of the water on wooded sites, lower tree limbs can be removed. (This may be a 

reasonable alternative to developing closer to the water’s edge.) Zoning requirements 

might dictate an additional 50- to 100-foot setback from the 100-year floodplain. 

— Slopes. Slopes of more than 25 percent should not be developed because of their high 

potential for erosion. Slopes between 15 and 20 percent can be developed using 

special site planning but should be avoided when possible. Slope maps can be 

prepared from USGS topographic maps by an engineer, planner, or landscape 

architect, but site visits should confirm these conditions. 

The following conservation areas typically are legally buildable but are historically or 

ecologically significant or desirable, and therefore they should be avoided when other land is 

available for development. 

— Soils. Soil surveys, whether they are based on existing maps produced by NRCS or 

data gleaned from on-site testing, identify well-drained soils suitable for treating 

wastewater, poorly drained soils that might result in leaky basements or wetland 

conditions, and steep or stony soils that would be difficult to build on. Existing soil 

survey data might not be detailed enough to characterize site conditions, depending 

on the spatial variability of soil types in the region. High-intensity soil surveys and 

site surveys that are accurate to 0.1 acre should be used in highly variable 

circumstances. 

— Significant wildlife habitats. Habitat for threatened or endangered wildlife, including 

travel corridors to food sources, homes, and breeding grounds, should be conserved. 

An additional buffer of open space is recommended. These habitat locations might 

have been officially documented already by state or local agencies. Habitat for 

wildlife species that are not threatened or endangered should also be considered for 

conservation areas where possible. Continuity in habitat areas is important; land that 

connects two isolated habitat areas provides a valuable corridor that extends the 

usable habitat for the species of concern. 

— Woodlands. Woodlands often provide valuable wildlife habitat and contribute to the 

aesthetic value of a property. Where areas are mostly forested and clearing is required 

for site development, however, areas of mature forest or areas with unique species 

composition should be of higher conservation priority. In areas where woodland is 

not the predominant land use, as much of the existing tree cover as possible should be 

conserved on the property. An effort should be made to maintain corridors that 

connect forested areas to provide as much continuous forested habitat as possible. 

4-10 
Management Measure 4: Site Development 

— Farmland. Agricultural lands can be conserved as open space if desired, although 

relatively small fields might not be lucrative and could pose a more significant water 

quality risk compared to residential development due to specific land management 

practices (tilling, fertilizer application) associated with agriculture. Another option for 

agricultural fields is to let them succeed to a more natural meadow state with grasses, 

wildflowers, and shrubs that could provide habitat for many birds and small 

mammals. 

— Historic, archaeological, and cultural features. Areas with historic significance can 

be identified from official lists such as the National Register of Historic Places and 

state and local inventories of historic and cultural resources. Landowners and local 

historians should also be consulted for detailed information about a site’s history. 

Although historic areas are not always protected from demolition, if other areas of the 

property are equally suitable for development, historic resources should be preserved. 

— Views into and out from the site. Development should be designed to blend well with 

the surrounding landscape. Because developers typically want to site buildings to take 

advantage of attractive views, they often build in areas where structures are highly 

visible. Siting buildings away from the pinnacles of ridges and hills, designing 

buildings with lower profiles, and preserving or planting trees to shield buildings 

from view are all techniques that can be used to reduce the visual impact of 

development on the landscape. Views can be created by cutting a limited number of 

trees to create “view tunnels,” or trimming lower limbs to create “view holes” 

through the foliage. 

— Aquifers and their recharge areas. An aquifer recharge area is where water moves 

downward to the water table. In other words, recharge areas replenish groundwater. 

Unconfined aquifers are not covered by a layer of impermeable rock and are open to 

receive water from the land surface. Unconfined aquifers are typically recharged in 

topographically high areas or through sandy or gravelly soils. These areas should be 

conserved as open space to maintain ground water recharge. They should also be 

buffered with vegetation to filter solids and associated pollutants from runoff. 

After background information has been obtained, the next step is to integrate the information and 

prioritize conservation areas. Typically, all of the features mentioned above are drawn onto 

overlay sheets or entered into a geographic information system (GIS). Once the significant 

features are shown together, areas most suitable for development become obvious. Where some 

conservation areas need to be sacrificed to achieve the development objectives, decisions must 

be made regarding ranking the conservation areas based on how special, unique, irreplaceable, 

environmentally valuable, historic, or scenic they are. Figure 4.3 shows an example site before 

development, developed with a conventional strategy, and developed with consideration of 

locational context and conservation areas (Arendt, 1996). 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Figure 4.3: Development of a conservation subdivision. The site before development (a) 

and as designed with conventional development (b); identification of legally unbuildable 

(c) and legally buildable (d) conservation areas with features to be protected; and 

delineation of potential development areas (e and f) (adapted from Arendt, 1996).

(a) (b)

(c) (d)

(e) (f)

100-yr floodplain 

and wetlands 

4-12 
Management Measure 4: Site Development 

Comparison of Traditional and Low Impact Development Scenarios in Delaware 

The Brandywine Conservancy and the Delaware Department of Natural Resources and Environmental 

Control presented a case study in Conservation Design for Stormwater Management (Delaware 

DNREC and the Brandywine Conservancy, 1997). The case study compares conventional site 

development to several alternative, low impact development scenarios at Chapel Run, a 96-acre site 

in Sussex County, Delaware. The Chapel Run site is located in a rural area and is categorized by 

Sussex County as a primarily agricultural area where low-density residential development is permitted. 

Conservation areas that were identified through a site investigation include a large area of woodland, 

much of which is on well-drained soils that generate little or no runoff, and a small area with steep 

slopes. 

The proposed conventional design dictates dividing the site into 142 lots 1⁄2 acre in size. The 

conventional design does not take into consideration the sensitive areas identified in the site 

assessment and results in a site with 100 percent of the area disturbed after clearing and grading. 

Overall site imperviousness under conventional development would be 29 percent, assuming 

conventional road widths. On-site runoff management would be accomplished by a curb and gutter 

system that conveys runoff to two detention basins. 

Two alternative designs were developed for the Chapel Run site: the parkway design and the village 

cluster design. Figure 4.4 shows lot layouts for the conventional and conservation designs. Table 4.1 

shows a theoretical side-by-side comparison of the three types of developments with respect to lot 

size and layout, amount of disturbed and impervious area, hydrology, and costs. Table 4.2 shows 

differences in itemized costs for infrastructure and management practices between conventional and 

low impact alternative designs. 

(a) 

(b)

(c)

Figure 4.4: Schematic drawings of conventional (a), parkway (b), and clustered (c) development scenarios 

for the Chapel Run subdivision (Delaware DNREC and the Brandywine Conservancy, 1997). 

4-13 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Comparison of Traditional and Low-Impact Development Scenarios in Delaware (continued)

Table 4.1: Theoretical comparison of conventional and low-impact alternative designs for the Chapel Run 

site (DE DNREC and the Brandywine Conservancy, 1997). (Reductions are compared to the conventional 

design.) 

Name Conventional Village Parkway 

Layout type Conventional Condensed cluster Lots configured along 

curving road 

Number of lots 142 142 142 

1/4-acre 

 Woodland and high 

recharge areas 

49.7%

14.9% 

48%

Two one-way lanes 

12 feet wide with a 

pervious median 

59.6%

Infiltration of runoff 

into depressed 

median (swales) 

along streets. Wide 

oval parkway centers 

used for 

retention/infiltration. 

These areas are 

designed with 

overflow piping to 

prevent flooding. 

at 

d 

as 

65

51 cfs 

114,082,682 

17,782,776 

35,502,938 

Lot size 1/2-acre 1/8-acre 

Areas conserved None Woodland and high

recharge areas 

Percent of site in 

open space 

0% 72.7% 

Impervious cover 29% 17.7% 

Impervious cover 

reduction — 38% 

Street width 

28 feet 20 feet 

Undisturbed areas 0% 67.5% 

Runoff management 

system 

Curb and gutter system 

that conveys runoff 

underground to two 

detention basins. 

Swale conveyance 

system along roads th

directs runoff to 

retention/ infiltration 

areas with levelspreading devices an

low berms. These 

retention/infiltration 

areas are located 

throughout the site. 

Several village greens

established on welldrained soils function 

both recreation and 

infiltration areas. 

Average curve 

numbera 78 66 

Peak runoff rate for a 

10-yr storma — 53 cfs 

Water budget (gal) 

Precipitation 

Runoff 

Recharge 

Evapotranspiration 

114,082,682 

31,584,217 

31,280,103 

51,223,261 

114,082,682 

21,812,868 

34,001,079 

58,208,796 60,802,278 

Costs b

 Total $2,460,200 

$17,325 

$1,174,716 

 Per lot $8,273 

$887,705 

$6,259 a

 From USDA-NRCS’s TR-55 model. 

b Total cost for the Parkway design shown here differs from total cost published in DE DNREC and the 

Brandywine Conservancy (1997). Total cost shown here is based on itemized costs, provided in Table 

4.2. These are conservative estimates, as in most cases additional costs such as grading have not 

been taken into account. 

4-14 
Management Measure 4: Site Development 

Comparison of Traditional and Low-Impact Development Scenarios in Delaware (continued)

Table 4.2: Theoretical comparison of itemized costs for conventional and low-impact alternative designs 

for the Chapel Run site (DE DNREC and the Brandywine Conservancy, 1997). 

Name Conventional Village Parkway 

Street 

Length installed 13,388 ft 11,828 ft 7,800 ft 

Unit cost $150/linear ft $85/linear ft $85/linear ft 

Total cost $2,008,200 $1,005,380 $663,000 

Storm water detention ponds 

Number installed 3 0 0 

Unit cost $16,000 per pond

Total Cost $48,000 $0 $0 

Storm water pipe 

Length installed 16,000 ft 2,000 ft 3,000 ft 

Unit cost $22/linear ft $22/linear ft $22/linear ft 

Total cost $352,000 $44,000 $66,000 

Endwalls/inlets 

Number installed 40 5 10 

Unit cost $1,300 each $1,300 each $1,300 each 

Total cost $52,000 $6500 $13,000 

Berms 

Length installed 0 1050 ft 1000 ft 

Unit cost $10/linear ft $10/linear ft 

Total cost $0 $10,500 $10,000 

Swales 

Length installed 0 22,570 ft 20,600 ft 

Unit cost $4.50/linear ft $4.50/linear ft 

Total cost $0 $101,565 $92,700 

Check dams 

Number installed 0 90 82 

Unit cost $75 each $75 each 

Total cost $0 $6771 $6150 

Reforestation 

Acres reforested 0 0 12.8 

Unit cost $2,925/ac 

Total cost $0 $0 $36,855 

Total a $2,460,200 $1,174,716 $887,705 a Total cost for the Parkway design shown here differs from total cost published in DE DNREC and the 

Brandywine Conservancy (1997). Total cost shown here is based on itemized costs. These are 

conservative estimates, as in most cases additional costs such as grading have not been taken into 

account. 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

4.3.2 On-Lot Impervious Surfaces 

4.3.2.1 Reduce the hydraulic connectivity of impervious surfaces 

Pollutant loading from impervious surfaces can be reduced by preventing the direct connection 

of the impervious area to an impervious conveyance system. This can be done in a number of 

ways, including: 

(1) Routing runoff over lawn areas to increase infiltration; 

(2) Discouraging the direct connection of downspouts to storm sewers, or the discharge of 

rooftop downspouts to driveways, parking lots, and gutters; 

(3) Substituting swale and pond systems for curbs and gutters to increase infiltration; or 

(4) Reducing the use of storm sewers to drain streets, parking lots, and backyards by routing 

runoff overland using curbless systems, curb cuts, sloped sidewalks, and bioretention 

cells. 

If runoff is directed over lawns, care should be taken to alleviate soil compaction. Urban lawns 

that are highly disturbed and compacted do not necessarily function as pervious surfaces (for 

more information on managing runoff from lawns and landscaping, see Management Measure 9). 

Figure 4.5 shows schematic representations of impervious areas that are directly connected and 

not directly connected (BASMAA, 1997). 

Figure 4.5: Schematic representation of directly connected and not-directly connected 

impervious areas (BASMAA, 1997). 

4-16 
Management Measure 4: Site Development 

The Urban Runoff Pollution Mitigation ordinance passed by the City of Santa Monica, 

California, requires new developments to implement management practices to collect 

precipitation, increase infiltration, and manage urban runoff on-site rather than after it enters the 

storm drain system. Infiltration trenches are the most common on-site practices for single-family 

homes in the city, but biofilters, swales, and porous pavement are also used. Since 1995, when 

the ordinance came into effect, 600 new developments have implemented management practices, 

resulting in a 1.2 million-gallon decrease in storm water runoff for each storm of 0.1-inch rainfall 

or greater (Shapiro, 2003). 

In Prince George’s County, Maryland, Cheng et al. (no date) measured runoff from adjacent 

watersheds to compare the effects of conventional versus low-impact subdivision design. One 

watershed was developed using conventional subdivision design (curb, gutter, and pipe storm 

drainage), while the other watershed was developed using low-impact development (LID) 

techniques, including curbless roads, networks of grassy swales to convey runoff, and 

bioretention areas (with drop inlet structures where necessary to convey concentrated flows 

during larger storms). After two years of monitoring, the researchers found that the average peak 

flow rate of the LID site was 56 percent of that of the conventional site, and surface runoff 

volume for the LID site was 60 percent of that of the conventional site. Only 15 percent of 

rainfall was converted to runoff in the LID watershed compared to 19 percent in the conventional 

watershed, and the LID site had delayed runoff hydrographs and a higher frequency of small 

flow rates compared to the conventional site, which had a higher frequency of larger flow rates. 

Gap Creek Low Impact Development Subdivision, Sherwood, Arkansas

The Gap Creek subdivision in Sherwood, Arkansas, was designed using a low impact development 

approach that involved implementing such practices as street designs that flow with the existing 

landscape, minimal site disturbance and preservation of native vegetation, preservation of natural 

drainage features, and a network of buffers and greenbelts that protect sensitive areas. The approach 

resulted in significant economic benefits arising from lower development costs, higher lot yield, and 

greater lot values (NRDC, 1999). 

The developer took advantage of the open space that was preserved to maximize the number of lots 

that were adjacent to the uncleared areas, enhancing their marketability and increasing the value of 

those properties. The LID plan reduced the amount of site clearing and grading, yielding lower site 

preparation costs. 

Additionally, enhancing natural drainage features resulted in less money spent on drainage 

infrastructure such as piping, curbs, gutters, and other runoff conveyance features. An additional cost 

savings was realized with shorter and narrower streets, which also reduced imperviousness. For 

example, the developer reduced street width from 36 to 27 feet and retained trees close to the curb 

line, resulting in savings of nearly $4,800 per lot. 

The greater lot yield and high aesthetic curb appeal also resulted in larger profits. The developer was 

able to sell lots for $3,000 more than larger lots in competing areas and sold nearly 80 percent of the 

lots within the first year. Additional benefits can be found in 23.5 acres of green space and parks 

(Toolbase Services, no date). 

The economic benefits are expected to exceed $2 million over original projected profits. Additional 

benefits of the LID design include lower landscaping and maintenance costs and more common open 

space and recreational areas. 

4-17 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

4.3.2.2 Practice rooftop greening 

Rooftop greening has become an increasingly common practice in Europe and other parts of the 

world. This practice involves growing vegetation on the roofs of businesses and homes to 

intercept rainfall and promote evaporation rather than runoff (Natural Carpets, 1998). Rooftop 

mats are typically multilayered and include prevegetated coir fiber mats, a mineral-based 

substrate, and a synthetic matrix (see Figure 4.6). The coir fiber mat absorbs rainfall; the mineral 

substrate provides the plants with nutrients; and the synthetic matrix promotes drainage. Mats 

can be used on roofs with slopes of up to 30 degrees and are capable of reducing runoff by twothirds (see Figure 4.7). These mats provide benefits other than runoff reduction, including: 

— Visual aesthetics 

— Protection of roofs from damaging solar radiation, wind, and precipitation 

— Insulation 

— Noise reduction 

— Habitat for wildlife 

Figure 4.6: Components of the vegetated roof cover (USEPA, 2000). 

4-18 
Management Measure 4: Site Development 

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

0.18

0.20

Time (5-minute intervals)

Inches

Rainfall

Runoff

2.5 mm

5.0 mm

Figure 4.7: Runoff attenuation efficiency for a 0.4-inch rainfall event with saturated 

media (USEPA, 2000). 

— Dust-trapping 

— Evaporation and ambient cooling 

Vegetation should be well-adapted to the growing conditions of the area where it is installed. 

Maintenance includes a limited amount of irrigation on steep slopes and periodic fertilization and 

weeding. Additional roof support might be necessary because the mats, when saturated with 

water, can add 5 to 17 pounds per square foot. 

In response to a court order requiring $3 billion in storm water improvements, Atlanta is 

targeting commercial buildings for the installation of green roofs, with the anticipation that the 

resulting decrease in storm water runoff volume will provide water quality benefits. Commercial 

buildings are being targeted because commercial rooftops cover a huge amount of surface area in 

the city (Copeland, 2002). 

Moran et al. (2004) studied runoff quality from two green roofs installed in North Carolina. They 

found that each green roof retained approximately 60 percent of the total recorded rainfall during 

a nine-month observation period. The green roofs reduced average peak flow by approximately 

85 percent. Water quality data indicated higher concentrations of total nitrogen and total 

phosphorus were present in the green roof runoff than in the control roof runoff and in the 

rainfall at each green roof site. The researchers attribute this to nitrogen and phosphorus leaching 

from the soil media, which was composed of 15 percent compost. A soil column test of three 

different green roof soil media indicated that reducing organic matter in the soil media will 

4-19 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Rooftop Meadow Demonstration Project, Philadelphia, Pennsylvania

Rooftop meadows typically use foliage and a lightweight soil mixture to either absorb or filter and 

detain rainfall (Miller, 1998). Roof meadows are designed to control low-intensity storms by 

intercepting and retaining or storing water until the peak storm event has passed, while allowing the 

runoff from higher-intensity storm events to be safely conveyed away from the building. The plants 

help retain the hydrologic function of intercepting and delaying rainfall runoff by capturing and holding 

precipitation in the foliage, absorbing water in the root zone, and slowing the velocity of direct runoff 

by extending the flowpath through the vegetation. 

A rooftop meadow demonstration project in Philadelphia, Pennsylvania, consists of a 3,000-ft2

 roof 

installed and monitored on top of an existing structure. The roof system was intended to mimic natural 

hydrologic processes of interception, storage, and detention to control the 2-year, 24-hour storm 

event. There are several distinguishing features of this rooftop meadow: (1) a synthetic underdrain 

layer that promotes rapid drainage of water from the surface of the roof deck; (2) a thin, lightweight 

growth medium that permits installation on existing conventional roofs without the need for structural 

reinforcement; and (3) a meadow-like setting of perennial Sedum varieties that have been selected to 

withstand the range of seasonal conditions typical of the Mid-Atlantic region without the need for 

regular maintenance. 

The installed roof meadow is 3.4 inches thick, including the drainage layer, and weighs less than 

5 lb/ft2

 when dry and less than 17 lb/ft2 when saturated. The moisture content of the medium at field 

capacity is 45 percent of the volume. The saturated infiltration capacity is 3.5 inches per hour. 

The runoff characteristics of the roof were simulated using rainfall records for 1994 from eastern 

Pennsylvania. The model predicted a 54 percent reduction in annual runoff volume and attenuation of 

54 percent and 38 percent, respectively, for the 2- and 10-year, 24-hour Type II storm events. 

Monitoring of the pilot project for real and synthetic storm events was also conducted for a period of 

9 months at 28- and 14-ft2

 trays. The most intense storm monitored was a 0.4-inch, 20-minute 

thunderstorm. The storm event occurred after an extended period of rainfall had fully saturated the 

medium. Although 44 inches of rainfall were recorded during this period, only 15.5 inches of runoff 

were generated from the trays. Runoff was negligible for storm events with less than 0.6 inch of 

rainfall. This demonstration project shows the advantages of reducing peak runoff rates on overloaded 

systems for a majority of the storm events and shows that some existing structures can be retrofitted 

to reduce runoff. 

reduce the amount of nutrient leaching. Based on the results of this study, caution should be used 

when implementing green roofs in nutrient-sensitive watersheds; green roof components such as 

soil media composition should be selected with consideration of receiving water limitations. 

Dunnett and Kingsbury (2004) describe examples of both large-scale and residential applications 

of green roofs and living walls, and they include technical information about constructing these 

structures in Planting Green Roofs and Living Walls. The authors cover structural engineering 

concerns as well as factors such as plant selection and environmental considerations that are 

important for the success of green roofs and living walls. The book is available for purchase at 

the Timber Press Web site at http://www.timberpress.com. 

Another resource for information about green roofs is the proceedings of a conference entitled 

Green Roofs for Healthy Cities. A CD-ROM of the proceedings can be purchased from 

http://www.greenroofs.org/portland/proceedings.php and includes information on green roof 

design and implementation, technical research, and policy developments. 

4-20 
Management Measure 4: Site Development 

A Better Site Design Approach to Runoff Management: Low Impact Development 

The goal of low impact development (LID) is to maintain and enhance the predevelopment hydrologic 

regime of urban and developing watersheds. LID focuses on managing runoff in small, cost-effective 

landscape features on each lot rather than conveying runoff to large, costly storm water ponds located 

at the bottom of large drainage areas. Hydrologic functions such as infiltration, ground water recharge, 

and depressional storage are maintained using simple, small-scale practices such as bioretention 

facilities. A key objective of LID is to reduce the hydraulic connectivity of impervious surfaces. For 

example, instead of allowing storm water to run from a downspout down a driveway and into a storm 

sewer, direct the runoff onto a lawn or other pervious area. By disconnecting rooftop runoff from the 

storm drainage system, a community can decrease the volume of water conveyed to a storm drain by 

as much as 50 percent (Pitt, 1986) and avoid treatment and storage costs, decrease system 

maintenance costs, and reduce instream impacts. To avoid soggy areas in lawns, water can be 

directed to specially designed depression storage areas such as bioretention or infiltration areas. 

The following is a list of fundamental practices of the LID approach that can be included in runoff 

management plans. These practices are presented in two publications by the Department of 

Environmental Resources of Prince George’s County, Maryland: Low-Impact Development Design 

Strategies: An Integrated Design Approach (2000a) and Low Impact Development Hydrologic Analysis 

(2000b). 

— Use hydrology as the integrating framework. Hydrology is used as the key feature when 

designing a development. Areas that play a critical role in the movement of water (e.g., 

streams, riparian and buffer areas, floodplains, wetlands, and ground water recharge sites) 

are identified first. Alternative layout schemes are then evaluated in terms of their impact on 

site hydrology. Key objectives are to minimize the amount of impervious cover created and to 

make created impervious areas function as “ineffective” impervious areas that are not directly 

connected to a storm drain network. 

— Think micromanagement. Site hydrology is analyzed and dealt with at small scales. Using 

natural drainage as a design element, integrated management practices are scattered 

throughout the site, allowing for runoff distribution and the retention of natural hydrologic 

functions such as infiltration, depressional storage, and interception. 

— Control runoff at the source. Management of runoff at or near the sources eliminates the need 

for large-scale runoff management practices such as concrete conveyance systems and 

storm water ponds. 

— Incorporate safety features into the design of management practices. LID practices can 

require diversions or drainage to allow for overflow of runoff from large storms and storm 

events that occur during saturated conditions. This emergency drainage will protect the 

longevity of the structural practice against damage from high runoff volumes and flow 

velocities and enhance the acceptance of LID in the community. 

— Use simple, nonstructural methods. Natural hydrologic functions rely on simple processes that 

promote infiltration, depressional storage, and interception of storm water. These 

characteristics can be implemented throughout the site using simple methods that incorporate 

native plants, soil, and gravel. 

— Create a multifunctional landscape. A goal of the LID approach is to create a landscape where 

runoff is micromanaged and controlled at the source. Runoff management practices and 

natural landscape features can be used in tandem to reduce postdevelopment runoff volume 

and maintain the predevelopment time of concentration. 

The Prince George’s County LID publications can be ordered through the Internet at EPA’s National 

Service Center for Environmental Publications Web site at http://www.epa.gov/ncepihom. They can 

also be ordered by phone, fax, or mail from USEPA/NSCEP, P.O. Box 42419, Cincinnati, Ohio 45242-

2419, toll-free 800-490-9198, fax 513-489-8695. 

4-21 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

4.3.2.3 Relax frontage and setback requirements 

Developers interested in increasing open space or conservation areas typically increase housing 

density by creating smaller lots or clustered developments and pool the space “savings” in a 

large open area accessible to all. This can be accomplished by reducing front, side, and rear yard 

setbacks and decreasing frontage distances. In addition to increasing housing density for open 

space development designs, relaxing frontage and setback requirements also decreases 

impervious cover. This occurs because narrower side yards mean narrower lots, which can in 

turn lead to shorter subdivision streets; shorter front yard setbacks lead to shorter driveways and 

sidewalks. 

Frontage distance can be reduced by providing garage access through rear alleys. This approach 

eliminates driveways and allows homes to be sited on narrower lots. This helps reduce road 

frontage requirements and accommodate more homes on a given amount of road. Because of 

their limited traffic, the alleys can be paved with alternative treatments to retain more pervious 

area. 

Areas with high potential for significant storm damage, earthquakes, or other catastrophes should 

take into consideration the appropriate setback distance to ensure emergency access in case of 

building collapse. 

4.3.2.4 Modify sidewalk standards 

Many conventional subdivision codes require paved sidewalks on both sides of the street in 

widths that range from 4 to 6 feet. Communities that want to reduce impervious cover and 

increase the use of pervious areas for runoff treatment should consider the following (always 

considering public safety first): 

— Allowing sidewalks on only one side of the street or building them only where there is 

pedestrian demand; 

— Increasing the distance between sidewalks and the street so sidewalk runoff has a better 

chance of infiltrating into the grass border area and not becoming street runoff. This will 

provide water quality as well as safety benefits; 

— Grading sidewalks so that runoff drains into the yard rather than toward the street; 

— Reducing the width of very wide sidewalks. Communities should consider the 

implications of reducing sidewalk widths, including pedestrian demand and wheelchair 

access, on a case-by-case basis. Three feet will typically allow passage for one 

wheelchair. Sidewalks in highly commercial areas and government centers should 

accommodate two wheelchairs abreast, but it may be appropriate for some residential 

areas to reduce sidewalk width to three feet. 

— Maintain sidewalk widths but use porous pavement (see Management Measure 5). 

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Management Measure 4: Site Development 

4.3.2.5 Modify driveway standards 

In a sense, driveways are small-scale parking lots that are designed to accommodate two to four 

cars. Typical residential driveways and parking pads often total 400 to 800 square feet. 

Communities that want to reduce driveway impervious cover should consider: 

— Shortening driveway length by shortening front yard setback requirements; 

— Narrowing driveway widths; 

— Encouraging the use of driveways that are shared by two or more homes; and 

— Providing incentives for use of alternative driveway surfaces that allow for infiltration, 

such as porous pavers, gravel, or a two-track surface with grass in between. 

4.3.3 Residential Street and Right-of-Way Impervious Surfaces 

The largest percentage of impervious cover in residential neighborhoods is typically associated 

with the streets, driveways, and sidewalks that together aid in the transport of people to and from 

their various destinations. Management practices associated with residential streets and their 

rights-of-way typically are focused on minimizing impervious cover or treating runoff. In 

general, these objectives can be achieved by developing, updating, or revising codes, ordinances, 

and standards that determine the size, shape, and construction of residential streets and their 

rights-of-way. 

4.3.3.1 Decrease street pavement width and length 

Streets typically make up the largest percentage of transport system impervious cover in 

residential neighborhoods. Communities can significantly reduce this type of cover in new 

developments by revising street standards so that street pavement widths are based on traffic 

volume, on-street parking needs, and other variables rather than requiring all streets to have one 

universal width. Additionally, communities can encourage developers to design street networks 

that minimize the total length of pavement. The length of residential streets can be reduced by 

altering the design and placement of new development. Techniques include: 

— Reducing frontage distances and side yard setbacks; 

— Allowing narrower lots; 

— Clustering smaller lots; 

— Reducing the number of non-frontage roads; and 

— Eliminating long streets that serve only a small number of homes. 

4.3.3.2 Decrease street right-of-way width 

A street right-of-way is a public easement corridor through which people, vehicles, runoff, utility 

services, and other items and materials move in, out, and around the development. A right-ofway usually includes the street itself, its gutters and curbs, and some amount of land on either 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

side of the street, which might contain sidewalks, utility easements, or other components. 

Options for minimizing right-of-way widths include: 

— Eliminating some right-of-way components; 

— Placing sidewalks on only one side of the street; 

— Running utility pipes, cables, and other infrastructure underneath street pavement (this 

can result in traffic congestion from road construction if the infrastructure needs to be 

repaired or replaced); or 

— Reducing street and sidewalk widths where appropriate. 

On-street parking is a variable that should be closely examined in communities where reducing 

impervious cover is a goal. Some communities have implemented a concept known as “queuing 

streets.” Queuing streets generally have one travel lane and one or two parking lanes. Cars wait 

between parked cars until approaching traffic passes before proceeding to the travel lane. This 

approach also helps slow traffic, which can improve safety. 

Street width must provide for utility work (common utilities include water, sewer, gas, cable, 

phone, power, and fiber optics). If the street width is reduced, utilities can be installed together in 

a concrete trench with a removable top for maintenance access (Matsuno, 2003). 

When considering these options, it is important to remember that public safety should not be 

compromised and traffic engineering principles must still be a significant design factor. In 

addition, areas with high potential for significant storm damage, earthquakes, or other 

catastrophes should take into consideration the appropriate right-of-way width to enable passage 

of emergency vehicles. 

The Headwaters Project: A Sustainable Community

In 1998 the Department of Planning and Development in Surrey, British Columbia, initiated the 

Headwaters Project to develop a real example of a sustainable community. Part of this project is the 

East Clayton Neighbourhood Concept Plan (The Headwaters Project, 2000), a green infrastructure 

plan that is an integrated system of “green” streets and affordable housing sites. It has narrow streets 

that use one-third less blacktop than typical roadways. Storm water management is achieved through 

natural infiltration, which minimizes runoff and avoids downstream flooding events. Information about 

East Clayton and a copy of the concept plan are available at http://www.sustainablecommunities.agsci.ubc.ca/projects/Headwaters/PDF/toc.pdf

4.3.3.3 Use alternative cul-de-sac designs 

Cul-de-sacs (roads with one open and one closed end) are a popular design element in 

community road networks. The intent of cul-de-sacs is to provide more homebuyers with 

premium, “end-of-the-road” lots. The typical “bulb” found at the closed end of a cul-de-sac, 

however, represents a particularly large concentration of impervious cover. Communities can 

reduce the amount of impervious cover created by bulb-ending cul-de-sacs by 

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Management Measure 4: Site Development 

— Eliminating cul-de-sac streets altogether; 

— Using alternative designs for turnarounds, such as a T-shaped turnaround or a looped 

road; 

— Reducing the radius of the turnaround bulb; or 

— Incorporating a pervious cover island in the center of the turnaround bulb that accepts 

runoff. 

As with modifications of street right-of-way width, public safety should not be compromised and 

traffic engineering principles must still be a significant design factor for this practice. Existing 

fire codes may dictate cul-de-sac width. Figures 4.8 and 4.9 show five turnaround options at the 

end of a residential street and the amount of impervious cover created by each option (Schueler, 

1995). 

4.3.4 Parking Lot Impervious Surfaces 

Parking lots are considered by some to be one of the most damaging land uses in the urban 

landscape (CWP, 2000). Not only are parking lots very efficient at concentrating and delivering a 

large amount of runoff to receiving waters, thus exacerbating erosion problems, but they also act 

as a repository for pollutants associated with automobiles, which include nutrients, trace metals, 

and hydrocarbons. 

Figure 4.8: Five turnaround options at the end of a residential street (Schueler, 1995). 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

5.024

4.397

2.826

2.512

1.25

0

1

2

3

4

5

6

40-ft radius 40-ft w/island 30-ft radius 30-ft w/island Hammerhead

Turnaround Options

Impervious Area (1,000 ft2

)

Figure 4.9: Impervious cover created by each turnaround option shown in Figure 4.8 

(Schueler, 1995). 

Innovative Turf Parking Lot Installation at a Connecticut Shopping Mall

The owners of Westfarms Mall, in the suburbs of Hartford, Connecticut, planned a 310,000-ft2

expansion that required an additional 4 acres of overflow parking (Wilson et al., 1998). Local zoning 

boards and members of the community balked at this proposal because of the high ratio of 

impervious-to-pervious surfaces and concern for the quality and quantity of runoff generated by the 

new additions. 

The traditional solution for handling the increased runoff was to install a large runoff detention pond, 

which would have cost $1million and was looked upon unfavorably by both the community and the 

mall owner. A 4-acre turf parking lot was implemented as an alternative and allows rainfall to infiltrate 

and recharge the ground water supply. To better support automobile traffic, the lot consists of a plastic 

honeycomb grid filled with sand and soil and laid atop a bed of crushed stone. Additionally, rooftop 

runoff is diverted to a tank located under the lot and the collected runoff is used to irrigate the turf. The 

turf would not hold up to everyday traffic, but overflow parking is needed only during the Christmas 

shopping season when the grass is dormant. 

The cost of installing the turf lot was $500,000, which is half the cost of installing a pond. Even though 

the turf installation was more expensive than traditional pavement installation, the mall owner 

estimated that the installation would break even within 5 years because of lower maintenance 

requirements. An additional benefit of this innovative design was for the mall owner to gain the support 

of community members and local planning commissions. 

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Management Measure 4: Site Development 

Traditionally, developers have provided an overabundance of parking as a convenience for 

shoppers, workers, and landowners. A goal of watershed managers should be to reduce the 

surface area of parking lots and integrate runoff treatment practices to reduce adverse impacts, 

while still providing enough spaces to meet the expected parking demand. This reduction can be 

accomplished by implementing better site design practices, such as: 

— Redesigning building and parking area layouts to reduce walking distances and provide 

more efficient layouts. 

— Ensuring that the number of spaces built reflects actual demand. Site planners should 

design the lot size to correspond to minimum local parking requirements and consider 

ways in which this requirement can be reduced. For example, less parking is needed if 

access to public transportation is provided. Also, a parking area can be shared if localities 

in close proximity have different peak parking times. For instance, a retail establishment 

with peak demand during weekdays can share parking with a church whose peak demand 

is on the weekend. 

— Sizing parking lot dimensions to meet everyday demand and designating additional 

“spillover” parking areas to handle peak demand. Because these spillover areas will 

receive less traffic, alternative paving techniques (see Management Measure 5) can be 

used to increase infiltration. 

— Reducing the dimensions of the normal parking spaces if allowable. Also, developers can 

designate a percentage of the available parking spaces for use by compact cars and reduce 

their dimensions correspondingly. 

— Building multilevel parking structures when feasible. (Parking structures can sometimes 

be impractical from a cost standpoint.) Green roofs can be used on these parking garages 

to reduce imperviousness. 

— Converting parking lot islands to bioretention areas (see Management Measure 5). 

— Building below-grade parking where it does not affect groundwater or other subsurface 

resources. 

— Working with municipalities to regulate the maximum number of parking spaces allowed 

in development, rather than a minimum. 

When parking area is reduced, functional landscaping can be used to improve the aesthetics of 

the site and to allow room for the installation of runoff treatment practices such as infiltration 

basins, filter strips, and dry swales or detention practices like those described in Management 

Measure 5. 

4.3.5 Xeriscaping Techniques 

Xeriscaping is a landscaping concept that maximizes water conservation by using siteappropriate plants and an efficient watering system. It involves the use of landscaping plants that 

need minimal watering, fertilization, and pesticide application, and practices that reduce water 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

demand. For instance, mulching can help retain water and humidity and reduce the need for 

irrigation. Shading and windbreaks can reduce evaporation, particularly from young plants. In 

contrast to overhead sprinklers, drip irrigation waters plants directly on the roots without wetting 

plant leaves, helping to reduce evaporation and control disease. Timers are available that allow 

automatic watering with drip irrigation systems. Watering early in the morning can also reduce 

evaporation, and prevent the propagation of disease that often results from leaving foliage wet 

overnight (Relf, 1996). Xeriscaping can reduce the contribution of landscaped areas to nonpoint 

source pollution, and it can reduce landscape maintenance by as much as 50 percent, primarily as 

a result of the following (Clemson University Cooperative Extension Service, 1991): 

— Reduction of water loss and soil erosion through careful planning, design, and 

implementation; 

— Reduction of mowing by limiting lawn areas and using proper fertilization techniques; 

and 

— Reduction of fertilization through soil preparation. 

The specific benefits resulting from xeriscaping will vary based on the local climate and site 

conditions. 

In 1991 the Florida legislature adopted a xeriscape law that requires state agencies to adopt and 

implement xeriscaping programs. The law requires that rules and guidelines be adopted for the 

implementation of xeriscaping along highway rights-of-way and on public property associated 

with publicly owned buildings constructed after July 1, 1992. Local governments are tasked with 

determining whether xeriscaping is a cost-effective measure for conserving water. If so, local 

governments are to work with the state water management districts in developing their xeriscape 

guidelines. Water management districts will provide financial incentives to local governments 

for developing xeriscape plans and ordinances. These plans must include: 

— Landscape design, installation, and maintenance standards; 

— Identification of prohibited plant species (invasive exotic plants); 

— Identification of controlled plant species and conditions for their use; 

— Specifications for maximum percentage of turf and impervious surfaces allowed in a 

xeriscaped area; 

— Specifications for land clearing and requirements for the conservation of existing native 

vegetation; and 

— Monitoring programs for ordinance implementation and compliance. 

The law also includes a provision requiring local governments and water management districts to 

promote the use of xeriscape practices in existing developed areas through public education 

programs. California has passed a law requiring all municipalities to consider enacting waterefficient landscape requirements. 

4-28 
Management Measure 4: Site Development 

— Establishes water budget goals for parks and golf courses. 

— Requires that new sprinkler systems on large turf areas meet minimum uniformity standards. 

— Requires spray irrigation to occur between 6:00 p.m. and 10:00 a.m. from April to September. 

The full text of the ordinance can be found at www.cabq.gov/resources. 

As a result of these changes in Albuquerque’s water conservation policy, the city’s water consumption 

has decreased by 24 percent and its irrigation professionals have experienced a substantial increase 

in business as landowners seek smarter solutions to irrigation problems. Improvements in irrigation 

technology and increased public awareness are likely to further decrease water consumption. 

— Establishes design requirements to discourage turf on steep slopes or adjacent to streets. 

— Limits high-water-use turf to 20 percent of the total landscape for all new developments. 

— Prohibits irrigation water from flowing or spraying into streets, storm drains, or adjoining 

property. 

The city also developed a new ordinance, the Water Conservation Landscaping and Water Waste 

Ordinance, that includes the following provisions: 

— Aggressive preservation of ground water quality. 

— Developing systems to use reclaimed wastewater and low-quality shallow ground water to 

irrigate landscaped areas in specific corridors of the community. 

— Developing facilities to treat and distribute city-owned surface water in combination with more 

limited use of the aquifer. 

— Reducing per capita water consumption by 30 percent. 

The City of Albuquerque, New Mexico, recently adopted a new strategy to encourage water 

conservation and to ensure a lasting water supply for years to come (Bennett, 1999). The strategy 

includes 

Water Conservation and Xeriscaping in Albuquerque, New Mexico

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

4.4 Information Resources 

In 1991 the Center for Watershed Protection published the Consensus Agreement on Model 

Development Principles to Protect Our Streams, Lakes, and Wetlands, which outlines the series 

of 22 nationally endorsed principles developed by the Site Planning Roundtable, a national crosssection of diverse planning, environmental, homebuilder, fire, safety, public works, and local 

government personnel, and details the basic rationale for their implementation. The Consensus 

Agreement can be purchased at http://www.cwp.org/. 

The Center for Watershed Protection also published Better Site Design: A Handbook for 

Changing Development Rules in Your Community in 1998. This document outlines 22 guidelines 

for better developments and provides a detailed rationale for each principle. Better Site Design

also examines current practices in local communities, details the economic and environmental 

benefits of better site designs, and presents case studies from across the country. It can be 

purchased at http://www.cwp.org/. 

Wildlife Reserves and Corridors in the Urban Environment: A Guide to Ecological Landscape 

Planning and Resource Conservation, by Lowell Adams and Louise Dove (1989) reviews the 

knowledge base regarding wildlife habitat reserves and corridors in urban and urbanizing areas, 

and it provides guidelines and approaches to ecological landscape planning and wildlife 

conservation in such areas. It can be purchased from the Urban Wildlife Resources Bookstore at 

http://users.erols.com/urbanwildlife/bookstor.htm. 

In 1997 Randall Arendt of the Natural Lands Trust, Inc., published Growing Greener: Putting 

Conservation into Local Codes. Growing Greener is a statewide community planning initiative 

designed to help communities use the development regulation process to their advantage to 

protect interconnected networks of greenways and permanent open space. The booklet can be 

downloaded in PDF format at http://www.dcnr.state.pa.us/growinggreener/growing.pdf. 

The Low Impact Development Center was established to develop and provide information to 

individuals and organizations dedicated to protecting the environment and our water resources 

through proper site design techniques that replicate preexisting hydrologic site conditions. More 

information about this organization can be found on the Low Impact Development Center Web 

site at http://www.lowimpactdevelopment.org/ or by contacting the Center at 301-345-0440. 

The Prince George's County, Maryland, Department of Environmental Resources produced two 

documents, Low-Impact Development Design Strategies: An Integrated Design Approach (EPA841-B-00-003) and Low-Impact Development Hydrologic Analysis (EPA-841-B-00-002), that 

discuss site planning, hydrology, distributed integrated management practice technologies, 

erosion and sediment control, and public outreach techniques that can reduce storm water runoff 

from new and existing developments. Both publications can be ordered free of charge through 

EPA’s National Service Center for Environmental Publications at 

http://www.epa.gov/ncepihom/index.htm. 

Residential Streets, prepared by the American Society of Civil Engineers, the National 

Association of Home Builders, and the Urban Land Institute (1990), discusses design 

considerations for residential streets based on their function and their place in the neighborhood. 

4-30 
Management Measure 4: Site Development 

The publication presents guidance on street widths, speeds, pavement types, streetscapes, rightsof-way, intersections, and drainage systems. 

The Institute of Transportation Engineers (ITE) published Traditional Neighborhood 

Development—Street Design Guidelines (1997), in which traditional neighborhood designs that 

support pedestrian movement over automobile traffic are discussed, and design concepts such as 

on-street parking, street width, and sight distances are presented. The publication also includes a 

practical discussion of the time needed for community acceptance and travel behavior changes. 

ITE also published Guidelines for Residential Subdivision Street Design (1993), which presents a 

discussion of the overall design of a residential subdivision with respect to the adequacy of 

vehicular and pedestrian access, minimizing excessive vehicular travel, and reducing reliance on 

extensive traffic regulations. It also provides design considerations for local and collector streets 

and intersections, including such topics as terrain classifications, rights-of-way, pavements, curb 

types, and cul-de-sacs. These publications are available through the Institute of Transportation 

Engineers, 525 School Street, SW, Suite 410, Washington, DC 20024-2797, (202) 863-5486. 

Street Design Guidelines for Healthy Neighborhoods is a guidebook intended to help 

communities implement designs for streets that are safe, efficient, and aesthetically pleasing. 

This publication can be purchased from the Local Government Commission’s Center for 

Liveable Communities Web site at http://www2.lgc.org/bookstore/topic.cfm?topicId=11. 

The Congress for the New Urbanism has compiled a database of jurisdictions across the country 

that have adopted reduced-width street standards (Cohen, 2000). The database also includes 

resources related to neighborhood design and transportation. The database can be viewed at 

http://www.sonic.net/abcaia/narrow.htm. 

EPA has compiled a number of resources on its Low Impact Development (LID) Web page, with 

links to Web sites, a literature review, fact sheets, and technical guidance. The Web site is 

accessible at http://www.epa.gov/owow/nps/lid/. 

The Local Government Commission has published a guidebook to assist local communities in 

overcoming regulatory obstacles to smart growth. Smart Growth Zoning Codes: A Resource 

Guide helps planners design zoning codes that encourage the construction of walkable, mixeduse neighborhoods. The guidebook comes with a CD-ROM containing examples of the best U.S. 

zoning codes and other resources. The book can be purchased for $25 from 

http://www2.lgc.org/bookstore/topic.cfm?topicId=1. 

Dunnett and Kingsbury (2004) describe examples of both large-scale and residential applications 

of green roofs and living walls and include technical information about constructing these 

structures in Planting Green Roofs and Living Walls. The authors cover structural engineering 

concerns as well as factors such as plant selection and environmental considerations that are 

important for the success of green roofs and living walls. The book is available for purchase at 

the Timber Press Web site at http://www.timberpress.com. 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

4.5 References 

Adams, L.W. 1999. Metropolitan greenways for recreation. The Urban Open Space Manager

4(4): 1. 

American Society of Civil Engineers, National Association of Home Builders, and Urban Land 

Institute. 1990. Residential Streets. American Society of Civil Engineers, Reston, VA; 

National Association of Home Builders, Washington, DC; and Urban Land Institute, 

Washington, DC. 

Anacostia Restoration Team. 1992. A Current Assessment of Urban Best Management Practices: 

Techniques for Reducing Nonpoint Source Pollution in the Coastal Zone. Anacostia 

Restoration Team, Department of Environmental Programs, Metropolitan Council of 

Governments, Washington, DC. 

Arendt, R. 1996. Conservation Design for Subdivisions: A Practical Guide to Creating Open 

Space Networks. Island Press, Washington, DC. 

Bay Area Stormwater Management Agencies Association (BASMAA). 1997. Start at the 

Source: Residential Site Planning & Design Guidance Manual for Stormwater Quality 

Protection. Bay Area Stormwater Management Agencies Association, Oakland, CA. 

Bay Area Stormwater Management Agencies Association (BASMAA). No date. Web & Flow. 

http://www.basmaa.org/. Accessed June 21, 2000. 

Bennett, D. 1999. Albuquerque reduces water consumption by 24 percent. Irrigation Business 

and Technology 7(6): 22–28. 

Buckeye Development LLC. No date. Pembroke Woods Low Impact Development (LID) 

Residential Subdivision, Emmittsburg, MD. 

http://www.buckeyedevelopment.net/lowimpactdevelopment.htm. Accessed September 

10, 2003. 

Center for Watershed Protection (CWP). 1998. Better Site Design: A Handbook for Changing 

Development Rules in Your Community. Center for Watershed Protection, Ellicott 

City, MD. 

Center for Watershed Protection (CWP). 2000. The benefits of better site design in commercial 

development. Watershed Protection Techniques 3(2): 647–656. 

Cheng, M., L.S. Coffman, Y. Zhang, and Z.J. Licsko. No date. Comparison of Hydrological 

Responses from Low Impact Development with Conventional Development. Prince 

George’s County Department of Environmental Resources, Largo, MD. 

Clemson University Cooperative Extension Service. 1991. Xeriscape: Landscape Water 

Conservation in the Southeast. Clemson University, Clemson, SC. 

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Cohen, A.B. 2000. Narrow Streets Database: A Congress for the New Urbanism Transportation 

Task Force Initiative. http://www.sonic.net/abcaia/narrow.htm. Last updated June 2000. 

Accessed May 10, 2001. 

Copeland, L. 2002. “Ecoroof” lures urbanites, planners back to garden. USA Today. December 

13, 2002. http://www.usatoday.com/news/nation/2002-12-03-roofs-usat_x.htm. Accessed 

June 27, 2003. 

Cote, M., J. Clausen, B. Morton, P. Stacey, and S. Zaremba. 2000. Jordan Cove Urban 

Watershed National Monitoring Project. In National Conference on Tools for Urban 

Water Resource Management and Protection, February 7–10, 2000, Chicago, IL. EPA625-R-00-001. U.S. Environmental Protection Agency, Office of Research and 

Development, Cincinnati, OH, pp. 1–14. 

Delaware DNREC and the Brandywine Conservancy. 1997. Conservation Design for 

Stormwater Management: A Design Approach to Reduce Stormwater Impacts from Land 

Development and Achieve Multiple Objectives Related to Land Use. Delaware 

Department of Natural Resources and Environmental Control, Dover, DE, and the 

Environmental Management Center of the Brandywine Conservancy, Chadds Ford, PA. 

Dunnett, N., and N. Kingsbury. 2004. Planting Green Roofs and Living Walls. Timber Press, 

Portland, OR. 

Goldman, S.J., K. Jackson, and T.A. Borstztynksy. 1986. Erosion and Sediment Control 

Handbook. McGraw-Hill, Inc., New York, NY. 

Institute for Transportation Engineers. 1993. Guidelines for Residential Subdivision Street 

Design. Institute for Transportation Engineers, Washington, DC. 

Institute for Transportation Engineers. 1997. Traditional Neighborhood Development—Street 

Design Guidelines. Institute for Transportation Engineers, Washington, DC. 

Kiesling, M. 1999. Pedestrian paths. Progress 9(3): 10–11. 

Laquatra, J., and G.L. Potter. 2000. Building a balance: Housing affordability and environmental 

protection in the USA. Electronic Green Journal.

http://egj.lib.uidaho.edu/egj12/laquatra1.html. Last updated April 22, 2000. Accessed 

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Lehner, P., G. P. Aponte Clark, D.M.Cameron and A.G. Frank. 1999. Stormwater Strategies: 

Community Responses to Runoff Pollution. Natural Resources Defense Council, 

Washington, DC. 

Matsuno, R. 2003. Comments on the Draft National Management Measures to Control Nonpoint 

Source Pollution from Urban Areas. King County Department of Transportation. King 

County, WA. 

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Miller, C. 1998. Vegetated roof covers: A new method for controlling runoff in urbanized areas. 

In Proceedings of the 1998 Stormwater Management Symposium, Villanova University, 

Philadelphia, PA. 

Moran, A., B. Hunt, and G. Jennings. 2004. A North Carolina Field Study to Evaluate Greenroof 

Runoff Quantity, Runoff Quality, and Plant Growth. 

http://www.bae.ncsu.edu/greenroofs/GRHC2004paper.pdf. Accessed March 19, 2005. 

National Association of Home Builders (NAHB). 2003. Smart Growth Case Study: Abraham’s 

Landing. http://www.nahb.org/generic.aspx?genericContentID=508. Accessed June 27, 

2003. 

Natural Carpets. 1998. Natural carpets protect roof and soil. Erosion Control November/ 

December: 25–26. 

Phillips, R.A., J.C. Clausen, M.E. Dietz, J.J. Engdahl, J. Alexopoulos, M.P. Cote, S. Zaremba, 

and B.L. Morton. 2000. Effectiveness of Construction BMPs on Water Quality in a LowImpact Subdivision. In 8th National Nonpoint Source Monitoring Workshop Field Trip, 

September 10–14, 2000, Hartford, CT. 

Pitt, R. 1986. Runoff controls in Wisconsin's priority watersheds. In Urban Runoff Quality: 

Proceedings of an Engineering Foundation Conference, June 23–27, 1986, Henniker, 

NH. American Society of Civil Engineers, Reston, VA, pp. 290–313. 

Prince George’s County, Maryland, Department of Environmental Resources. 2000a. LowImpact Development Design Strategies: An Integrated Design Approach. Prince George’s 

County, Maryland, Department of Environmental Resources, Programs and Planning 

Division, Largo, MD. 

Prince George’s County. 2000b. Low-Impact Development Hydrologic Analysis. Prince George’s 

County, Maryland, Department of Environmental Resources, Programs and Planning 

Division, Largo, MD. 

Relf, D. 1996. Irrigating the Home Garden. Virginia Cooperative Extension. 

http://www.ext.vt.edu/pubs/envirohort/426-322/426-322.html. Accessed June 12, 2003. 

Schueler, T. 1995. Site Planning for Urban Stream Protection. Metropolitan Washington 

Council of Governments, Washington, DC. 

Shapiro, N. 2003. The Stranger Among Us: Urban Runoff, the Forgotten Local Water Resource.

In Proceedings, National Conference on Urban Stormwater: Enhancing Programs at the 

Local Level, February 17-20, 2003, Chicago, IL. 

Sutherland, R.C. 1995. Methodology for Estimating the Effective Impervious Area of Urban 

Watersheds. Technical Note 58. Watershed Protection Techniques 2(1): 282–283. 

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Toolbase Services. No date. Low Impact Development (LID) Practices for Storm Water 

Management. 

http://www.toolbase.org/tertiaryT.asp?TrackID=&CategoryID=1325&DocumentID=2007. 

Accessed March 23, 2005. 

U.S. Environmental Protection Agency (USEPA). 1996. Protecting Natural Wetlands: A Guide 

to Stormwater Best Management Practices. EPA-843-B-96-001. U.S. Environmental 

Protection Agency, Office of Water, Washington, DC. 

http://www.epa.gov/owow/wetlands/pdf/protecti.pdf. Accessed June 27, 2003. 

U.S. Environmental Protection Agency (USEPA). 1999. Street Storage System for Control of 

Combined Sewer Surcharge: Retrofitting Stormwater Storage into Combined Sewer 

Systems. EPA-600-R-00-065. U.S. Environmental Protection Agency, Office of Research 

and Development, Urban Watershed Management Branch, Cincinnati, OH. 

http://www.epa.gov/ednnrmrl/publications/reports/epa600r00065/epa600r00065.htm. 

U.S. Environmental Protection Agency (USEPA). 2000. Vegetated Roof Cover. EPA-841-B-00-

005D. http://www.epa.gov/owow/nps/roofcover.pdf. Accessed September 19, 2005. 

Wilson, A., J.L. Uncapher, L. McManigal, L.H. Lovins, M. Cureton, and W.D. Browning. 1998. 

Green Development: Integrating Ecology and Real Estate. Rocky Mountain Institute, 

Snowmass, CO, p. 144. 

Zickler, L. 2002, July 25. Managing stormwater in Pierce County: Kensington Estates case study 

sheds light on low impact development. Seattle Daily Journal. 

http://www.djc.com/news/en/11135654.html. Last updated July 25, 2002. Accessed April 

14, 2004. 

Zielinski, J., D. Caraco, and R. Claytor. 2000. Comparative nutrient export and economic 

benefits of conventional and better site design techniques. In National Conference on 

Tools for Urban Water Resource Management and Protection, February 7–10, 2000, 

Chicago, IL. EPA-625-R-00-001. U.S. Environmental Protection Agency, Office of 

Research and Development, Cincinnati, OH, pp. 280–289. 

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4-36 
Management Measure 5: New Development Runoff Treatment 

MANAGEMENT MEASURE 5 

NEW DEVELOPMENT RUNOFF TREATMENT 

5.1 Management Measure 

By design or performance (a) reduce the postdevelopment loadings of total suspended solids 

(TSS) so that the average annual TSS loadingsa

 are no greater than the predevelopment loadings, 

or (b) reduce the average annual TSS loadings by a minimum of 80 percent of the influent 

concentration of TSSb

. 

Maintain the postdevelopment average volume and peak runoff rates at levels that are similar to 

predevelopmentc levels or, through planning and/or design, control offsite discharges of runoff to 

prevent erosive impacts to downstream channels or shorelines. 

Maintain discharge temperatures in runoff at levels similar to predevelopment levels or at levels 

that will protect aquatic communities from the thermal impacts of runoff.

 

a

 In general, calculations of average annual TSS loadings will be based on TSS loadings from all storms below or 

equal to a predetermined maximum storm size. The most commonly used upper threshold that states use to calculate 

annual average TSS loadings is the 2-year, 24-hour storm. However, some states have recently reevaluated the 

benefits of controlling the 2-year versus the 1-year, 24-hour storm and, as a result, have adopted standards that 

require the control of all storms less than or equal to the 1-year, 24-hour storm. 

EPA interprets predevelopment conditions to mean those conditions that exist prior to the current land use. In 

situations where the previous land use has resulted in unacceptable erosion and significant sediment movement 

offsite, a baseline reference condition can be used (e.g., the typical TSS loading rates from forested sites or 

meadows in the area). Average annual TSS loading calculations also should be based on the TSS discharge 

concentrations that occur after the site has been permanently stabilized. 

b

 It is anticipated that the total TSS reductions will be calculated based on all reductions achieved through a system 

of structural and nonstructural management practices. The intent of this guidance is to promote the implementation 

of runoff management programs that protect receiving waters from increases of suspended solids that may, on an 

individual or cumulative basis, threaten or impair surface waters. Management practices and systems of practices 

should be selected based on achievement of water quality standards throughout the receiving watershed. TSS 

loading reduction goals therefore should be determined by assessing the capacity of the receiving water body to 

assimilate TSS from all contributing sources. EPA acknowledges that, in some jurisdictions, reducing 80 percent of 

the influent TSS concentration is not reasonable due to the presence of significant concentrations of colloidal 

particles. EPA also understands that treatment of these particles in many cases is not necessary to protect receiving 

waters and meet state or local water quality standards. In such cases, design or performance requirements should 

protect receiving waters from impairment from TSS loadings above the ambient TSS in receiving waters that are not 

due to anthropogenic sources. 

c

 As with the TSS element of the measure, term predevelopment refers to runoff rates and volumes that exist on-site 

immediately before the planned land disturbance and development activities occur. Predevelopment is not intended 

to be interpreted as that period before any human-induced land disturbance activity has occurred. Watershed 

managers need to determine an appropriate reference or management condition as an objective to achieve. Also, for 

the purposes of this element of the management measure, the term similar is defined as “resembling though not 

completely identical.” 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

5.2 Management Measure Description and Selection 

5.2.1 Description 

During the development process, both the existing landscape and hydrology are altered. As 

development occurs, the following changes are likely to occur: 

— Soil porosity decreases due to removal of vegetation and compaction of topsoil by 

construction equipment; 

— Impermeable surfaces (paving and rooftops) increase (see Introduction); 

— Artificial conveyances such as pipes and concrete channels are constructed; 

— Slope angles become less acute; 

— Vegetative cover decreases; and 

— Surface roughness decreases. 

These changes result in increased runoff volume and velocity, which may lead to accelerated 

erosion of streambanks, steep slopes, and unvegetated areas (Novotny, 1991). The grading of 

urbanized areas can increase the downward slope to a water body and destroy riparian buffer 

zones, or developers may level a site to facilitate construction activities. Destruction of in-stream 

and riparian habitat, increases in water temperature, streambed scouring, and downstream 

sedimentation of streambed substrates, riparian areas, and estuarine habitats may occur. 

Everyday activities that occur after development may cause the discharge of pollutants in runoff 

that can have harmful effects on waters and habitat. Pollutants related to vehicle petroleum and 

coolant leaks and overflows, tire and brake wear, pet waste, pesticides, and fertilizers can be 

carried into estuaries, streams, rivers, and lakes through runoff. Soils and sediment can constitute 

a significant fraction of the solids on urban surfaces. Weather related erosion and transport of 

eroded soil (e.g., by wind and rain) increases solids in urban areas. Other sources of solids on 

urban surfaces are wear of automotive parts (brake pads, tires), combustion products from dieseland gasoline-fueled engines, fireplaces, construction sites, and industrial facilities. An extensive 

discussion of these pollutants is presented in Chapter 1. 

The goals of the new development runoff treatment management measure are to: 

— Retain the predevelopment or pre-disturbance hydrological conditions of both surface and 

ground water; 

— Remove suspended solids and associated pollutants entrained in runoff that result from 

activities occurring during and after development; 

— Decrease the erosive potential of increased runoff volumes and velocities associated with 

development-induced changes in hydrology; 

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Management Measure 5: New Development Runoff Treatment 

— Preserve natural systems, including in-stream habitat, riparian areas, and wetlands; and 

— Reduce the thermal impacts that result from impervious surfaces and treatment devices 

with large amounts of surface exposed to sunlight such as wet ponds. 

Several issues require clarification to fully understand the scope and intent of this management 

measure. The watershed protection (3), site development (4), and new development runoff 

treatment (5) management measures are intended to be used together within a comprehensive 

framework to reduce nonpoint source pollution. Applied on-site and throughout watersheds, 

these three management measures can be used together to provide increased watershed 

protection and help prevent erosion, flooding, and increased pollutant loads generally associated 

with poorly planned development. Implementation of the watershed protection and site 

development management measures can help achieve the goals of the new development runoff 

treatment management measure. 

5.2.1.1 Pollutants and total suspended solids 

Many pollutants bind to and are entrained in sediment or particulate loadings. Particulates 

include suspended, settleable, and bedload solids. Metals, phosphorus, nitrogen, hydrocarbons, 

and pesticides are commonly found in urban sediments. The correlation between total suspended 

solids (TSS) and specific pollutants may vary (URS Greiner Woodward Clyde, 1999). 

TSS is a measure of the concentrations of sediment and other solid particles suspended in the 

water column of a stream, lake, or other water resource. TSS is an important parameter because 

it quantifies the amount of sediment entrained in runoff. This information can be used to link 

sources of sediments to the resulting sedimentation in a stream, lake, wetland, or other water 

resources. As shown previously, TSS is also an indirect measure of other pollutants carried by 

runoff, because nutrients (phosphorus), metals, and organic compounds are typically attached to 

sediment particles. For these reasons TSS was selected as the prime or sole parameter associated 

with the first element of this management measure. 

Sansalone and Buchberger (1997) found that the relative proportional mass of heavy metals (Zn, 

Cu, Pb) in highway runoff and snowbank samples increased with decreasing particle size. This 

effect was attributed to the increase in surface area binding sites that were present with smaller 

particles. In another study, Sansalone et al. (1998) observed that the greatest mass of 

contaminants in highway runoff is found on particles in the 425 to 850 micron (μm) range. 

Because average particle size varies across the U.S., it makes sense to address the particle size 

that most effectively captures the highest percentage of associated pollutants. 

The quantity and size range of the suspended particles measured and reported as TSS at any 

given time depends on many factors including: 

— The composition and extent of the sources of suspended solids in the watershed; 

— The magnitude and duration of storms or dry weather periods preceding the sampling; 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

— Flow velocity, turbulence, and other conditions that promote the suspension of solids in 

the water column; and 

— The sampling techniques employed. 

Generally, individual particles found in a TSS sample are 62 μm (0.062 μm) or less in diameter 

and classified as either silts or clays (Table 5.1). Solids greater than 62 μm can also be found in 

the water column if conditions are turbulent enough to keep them in suspension. 

Table 5.1: Sediment particle size distribution (shaded classes are found in a typical urban 

TSS sample). 

General Class Class Name Diameter (μm) 

Very coarse sand 2000–1000 

Coarse sand 1000–500 

Medium sand 500–250 

Fine sand 250–125 

Sand 

Very fine sand 125–62 

Coarse silt 62–31 

Medium silt 31–16 

Fine silt 16–8 

Silt 

Very fine silt 8–4 

Coarse clay 4–2 

Medium clay 2–1 

Fine clay 1–0.5 

Very fine clay 0.5–0.24 

Clay 

Colloids < 0.24

Erosion and entrainment of solids in runoff occur primarily during rainfall. Rainfall varies in 

magnitude through time, with large rainstorms occurring less frequently than small showers. 

Collectively, all the rainfall occurring during the year contributes to the annual sediment yield 

from a site. In order to focus on typical annual yields, however, the management measure states 

that yield calculations are to be based on the average annual TSS loadings from all storms less 

than or equal to the two-year, 24-hour storm. Setting this threshold eliminates the need to 

calculate or integrate the impacts of larger infrequent storms into the average annual sediment 

yield calculation. 

The annual TSS loadings can be calculated by adding the TSS loadings that can be expected 

during an average one-year period from precipitation events less than or equal to the two-year, 

24-hour storm. Removal of 80 percent of TSS can be achieved by reducing, over the course of 

the year, 80 percent of these loadings. 

Critics of the TSS standard suggest that the sampling and analysis protocols employed for this 

measure do not fully capture the entire range of particle sizes found in some kind of samples. 

More specifically, TSS protocols tend to under-sample larger solids and therefore yield lowerthan-actual values for management practice pollutant removal efficiency. However, undersampling the larger particles that would easily settle out in a runoff treatment control results in 

higher overall removal rates of solids and fewer solids discharged to surface waters. 

5-4 
Management Measure 5: New Development Runoff Treatment 

There are alternatives to the TSS method, including turbidity and suspended sediment 

concentration (SSC). Monitoring turbidity in urban runoff is advantageous because the 

measurements can be conducted in situ using continuous methods (e.g., Secchi disk). It should be 

noted, however, that using turbidity as a surrogate for TSS may be appropriate only in instances 

where a strong statistical correlation has been established, such as in low-energy environments 

like lakes and estuaries. This correlation should be established on a case-by-case basis if 

turbidity is to be used as a surrogate. 

The SSC method is used by the U.S. Geological Survey (USGS) as the standard for determining 

concentrations of suspended material in surface water samples (USGS, 2000). Gray et al. (2000) 

examined the comparability of SSC and TSS measurements. SSC and TSS are the predominant 

analytical methods used to quantify concentrations of solid-phase material in surface waters. 

SSC values are obtained by measuring the dry weight of all the sediment from a known volume 

of a water-sediment mixture. TSS data are produced by several methods, most of which involve 

measuring the dry weight of sediment from a known volume of a subsample of the original. 

Analysis of paired SSC and TSS data showed bias in the relationship between SSC and TSS. In 

samples where sand-size material was greater than nearly a quarter of the dry sediment mass, 

SSC values tended to be higher than corresponding paired TSS values. 

According to Gray, the SSC method produces relatively reliable results for natural water 

samples, regardless of the amount or percentage of sand-size material in the samples. SSC and 

TSS are not comparable and should not be used interchangeably. Rather, the authors suggest 

using the SSC analytical method to enhance the accuracy and comparability of suspended solidphase concentrations of natural waters (Gray et al., 2000). More information about the SSC 

analytical method can be found at http://www.astm.org/ by searching for standard number 

ASTM D 3977-97, Standard Test Method for Determining Sediment Concentration in Water 

Samples (ASTM International, 2002). 

5.2.1.2 Runoff 

Runoff management programs have traditionally focused on reducing or preventing induced 

flooding from new development. Performance standards were typically developed to control 

large storms, e.g., 50- or 100-year storms. Although the control of these large storms is still 

essential, it has become apparent in the last 20 years that a broad range of storms must be 

managed to prevent streambed and streambank erosion. Recent research points to the need to 

control total discharge volumes and rates so that they do not result in stream channel 

degradation. As a result, some states and local governments have developed performance 

requirements that are intended to prevent stream channel erosion as well as flooding of 

downstream properties. 

This management measure was written to address the control of both peak runoff rates and 

average runoff volumes with the intent to maintain postdevelopment runoff characteristics at 

predevelopment levels. Even though EPA recommends that structural runoff controls be 

designed to control all storms less than or equal to the two-year, 24 hour storm, state and local 

governments should determine the locally appropriate storm size threshold to control based on 

local hydraulics, hydrology, meteorology and other regional and local factors. Watershed 

managers also should consider the development and implementation of volume and peak 

5-5 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

discharge performance standards to address problems associated with the frequency and duration 

of erosive flows (MacRae and Rowney, no date). The use of low-impact development (LID) 

techniques may be one way to achieve these goals (Prince Georges’ County, Maryland, 

Department of Environmental Resources, 2000a, 2000b).

5.2.2 Management Measure Selection 

This management measure was selected because of the following factors: 

— Removal of 80 percent of TSS is assumed to control heavy metals, phosphorus, and other 

pollutants. 

— Several states and local governments have implemented a TSS removal treatment 

standard of at least 80 percent. Table 5.2 presents TSS reduction standards and design 

criteria for select state and local runoff management programs. 

— Analysis has shown that constructed wetlands, wet ponds, and infiltration basins can 

remove 80 percent of TSS, provided they are designed and maintained properly. Other 

practices or combinations of practices can also be used to achieve the goal. 

— A number of flood control practices can control postdevelopment volume and peak runoff 

rates and maintain predevelopment hydrological conditions, which will reduce or prevent 

streambank erosion and stream scouring. Table 5.3 presents peak discharge and volume 

standards and design criteria for select local runoff management programs. 

— Urban streams often experience elevated temperatures due to an increase in impervious 

areas and a decrease in vegetative cover that would normally provide shading for 

wetlands and stream channels. Many of the practices presented in this management 

measure and throughout this guidance, such as infiltration practices, riparian buffers, and 

urban forestry, help to lower stream temperatures. Practices such as retention ponds may 

contribute to temperature elevation and should not be used in areas with temperaturesensitive fish or macroinvertebrates unless the other measures are taken to counteract this 

effect (i.e., plant vegetation to shade ponds, wetlands, or channels). 

Table 5.2: Select local and state programs with TSS performance standards (adapted from 

Watershed Management Institute [WMI], 1997a). 

Community/State Standard Criteria 

Olympia, WA 80 percent removal of suspended solids. Treat runoff volume of six-month, 24 hr 

storm 

Orlando, FL Reduce average annual TSS loading by 80 

percent. 

Treat first half-inch of runoff or the runoff 

from the first inch of rainfall, whichever is 

greater. 

Winter Park, FL Reduce average annual TSS loading by 80 

percent. 

Treat the first inch of runoff by retention. 

Baltimore Co., MD Remove at least 80 percent of the average 

annual TSS loading. 

Treat the first half-inch of runoff from the 

site’s impervious area. 

South Florida Water 

Management District 

Remove at least 80 percent of the average 

annual TSS loading. 

Treatment volume varies from 1.0 to 2.5 

inches times percent impervious area. 

5-6 
Management Measure 5: New Development Runoff Treatment 

Table 5.2 (continued). 

Community/State Standard Criteria 

Delaware Remove at least 80 percent of the annual 

TSS loading. 

Treat the first inch of runoff by approved 

management practices. 

Florida Remove at least 80 percent of the average 

annual TSS loading. 

Treatment volume varies from 0.5 to 1.5 

inches depending on the practice. 

New Jersey 80 percent reduction in TSS. Treat runoff volume of a storm of 

>1.25inches in two hours or the one-yr, 24-

hr storm. 

South Carolina Remove at least 80 percent of the average 

annual TSS loading. 

Treatment volume varies from 0.5 to 1.0 

inch depending on the practice. 

Table 5.3: Select local programs with peak discharge and/or runoff volume performance 

standards (adapted from WMI, 1997a). 

Community/State Peak discharge Volume 

Alexandria, VA Postdevelopment rate cannot exceed 

predevelopment rate for two-yr and 10-yr, 

two-hr storm. 

None 

Austin, TX Postdevelopment rate cannot exceed 

predevelopment rate for two-, 10-, 25-, and 

100-yr, 24-hr storm. 

None 

Bellevue, WA Postdevelopment rate cannot exceed 

predevelopment rate for two- and 10-yr, 

two-hr storm. 

Multiple release rates for detention 

systems. 

Olympia, WA Postdevelopment rate cannot exceed 

predevelopment rate for two-yr and 100-yr, 

24-hr storm. 

Must infiltrate all of the 100-yr vol. on-site 

if percolation rate greater than 6 inches per 

hr. 

Orlando, FL Postdevelopment rate cannot exceed 

predevelopment rate for 25-yr, 24-hr storm.

In closed basins, retain runoff from 100-yr, 

24-hr storm. 

Washington, DC Postdevelopment rate cannot exceed 

predevelopment rate for two-, 10-, and 

100-yr, 24-hr storm. 

None 

Clark Co., WA Postdevelopment rate cannot exceed 

predevelopment rate for two-, 10- and 100-

yr, 24-hr storm. 

Post-development vol. cannot exceed 

predevelopment vol. for two-yr, 24-hr 

storm. 

SW Florida Water 

Management District 

Postdevelopment rate cannot exceed 

predevelopment rate for 25-yr, 24-hr storm.

Post-development vol. cannot exceed 

predevelopment vol. for 25-yr, 24-hr 

storm.

5-7 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

— In Maryland, local governments are usually 

responsible for storm water management 

review authority. Prior to design, applicants 

should always consult with their local 

reviewing agency to determine if they are 

subject to additional storm water design 

requirements. In addition, certain earth 

disturbances may require NPDES 

construction general permit coverage from 

MDE. 

— Runoff from land uses or activities with 

higher potential for pollutant loadings, 

sometimes referred to as hotspots, may 

require the use of specific structural runoff 

control and pollution prevention practices. In 

addition, runoff from a hotspot land use may 

not be infiltrated without proper 

pretreatment. 

— Certain industrial sites are required to 

prepare and implement a storm water 

pollution prevention plan (SWPPP) and file 

a notice of intent (NOI) under the provisions 

of Maryland’s Storm Water NPDES general 

permit. The SWPPP requirement applies to 

both existing and new industrial sites. 

— Redevelopment, defined as any 

construction, alteration, or improvement 

exceeding 5,000 square feet of land 

disturbance on sites where existing land use 

is commercial, industrial, institutional, or 

multi-family residential, is governed by 

special sizing criteria depending on the 

increase or decrease in impervious area 

created by the redevelopment. 

— Every management practice shall have an 

acceptable form of water quality 

pretreatment. 

— All management practices shall have an 

enforceable operation and maintenance 

agreement to ensure the system functions 

as designed. 

— Runoff to critical areas with sensitive 

resources may be subject to additional 

performance criteria or may need to use or 

restrict certain management practices. 

— To protect stream channels from degradation, 

Cpv shall be provided by 12 to 24 hours of 

extended detention storage for the 1-year storm 

event. Cpv shall not be provided on the Eastern 

Shore unless the appropriate approval authority 

deems it necessary on a case-by-case basis.

— On the Eastern Shore, the postdevelopment 

peak discharge rate shall not exceed the 

predevelopment peak discharge rate for the 2-

year frequency storm event. On the Western 

Shore, local authorities may require that the 

postdevelopment 10-year peak discharge not 

exceed the predevelopment peak discharge if 

the channel protection storage volume (Cpv) is 

provided. In addition, safe conveyance of the 

100-year storm event runoff control practices 

shall be provided. 

— Structural management practices for new 

development shall be designed to remove 80 

percent and 40 percent of the average annual 

postdevelopment TSS and total phosphorus 

loads, respectively. It is presumed that a 

management practice complies with this 

performance standard if it is sized to capture 

the prescribed water quality volume, designed 

according to the specific performance criteria 

outlined in the Maryland Stormwater Design 

Manual (MDE, 2000), constructed properly, and 

maintained regularly. 

— Water quality management shall be provided 

through the use of structural and nonstructural 

controls. 

— Annual ground water recharge rates shall be 

maintained by promoting infiltration through the 

use of structural and nonstructural methods. At 

a minimum, the annual recharge from 

postdevelopment site conditions shall mimic the 

annual recharge from predevelopment site 

conditions. 

— Runoff generated from development and 

discharged directly into a jurisdictional wetland 

or waters of the State of Maryland shall be 

adequately treated. 

— Site designs shall minimize runoff generation 

and maximize pervious areas for runoff 

treatment. 

To prevent adverse impacts from runoff, the Maryland Department of the Environment (MDE, 2000) 

developed 14 performance standards for development sites. These standards apply to any 

construction activity disturbing 5,000 or more square feet of land. The following standards are 

required at all sites where runoff management is necessary: 

General Performance Standards for Storm Water Management in Maryland 

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Management Measure 5: New Development Runoff Treatment 

The Delaware Department of Natural Resources and Environmental Conservation (2005) developed 

the Delaware Urban Runoff Management Model (DURMM) to quantitatively estimate how “green 

technology” management practice designs achieve pollutant removal and flow reductions. Green 

technology includes the following management practices: 

− Conservation site design 

− Source area disconnection 

− Biofiltration swales/grassed swales 

− Terraces 

− Bioretention structures 

− Infiltration practices 

These green technologies address some of the drawbacks of traditional runoff controls, including the 

following: 

− Ponds and wetlands do not necessarily protect against streambank erosion 

− Ponds and wetlands do not recharge groundwater. 

− Ponds and wetlands require substantial land area 

− Ponds and wetlands require significant maintenance. 

− Discharges from multiple structural practices can overlap, resulting in downstream flooding. 

− Discharges can elevate stream temperatures and sometimes contain high levels of algae. 

DURMM provides a quantitative approach to define the benefits of conservation design and quantifies 

runoff reductions and pollutant reductions from filter strips, biofiltration and grassed swales, terraces, 

bioretention structures, and infiltration trenches. It also quantifies runoff reductions from source area 

disconnection. The Delaware Department of Natural Resources and Environmental Conservation is 

also developing a companion document specifically focused on riparian buffer system design. 

Additional information on green technology BMPs or DURMM can be obtained by contacting 

Delaware’s Division of Soil & Water Conservation at 302-739-4411. 

Delaware Urban Runoff Management Model

5.2.3 General Categories of Urban Runoff Control 

Structural practices to control urban runoff rely on several basic mechanisms: 

— Infiltration; 

— Filtration; 

— Detention/retention; and 

— Evaporation. 

5.2.3.1 Infiltration practices 

Infiltration facilities are designed to capture a treatment volume of runoff and percolate it 

through surface soils into the ground water system. This process: 

— Reduces the total volume of runoff discharged from the site, which, in turn, decreases 

peak flows in storm sewers and downstream waters; 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

— Filters out sediment and other pollutants by various chemical, physical, and biological 

processes as runoff water moves through the bottom of the infiltration structure and into 

the underlying soil; and 

— Augments ground water reserves by facilitating aquifer recharge. Groundwater recharge 

is vital to maintain stream and wetland hydrology. During dry weather, ground water 

recharge helps to assure baseflow necessary for survival of biota in wetlands and streams. 

Treatment effectiveness depends on whether the facility is sited on-line or off-line, and on the 

sizing criteria used to design the facilities. Online systems receive all of the runoff from an area. 

Off-line practices receive diverted runoff for treatment and isolate it from the remaining fraction 

of runoff, which must still be controlled to prevent flooding. Off-line infiltration practices 

prevent all of the TSS and other pollutants contained in the volume of runoff infiltrated from 

exiting the site. Thus, the total annual load reduction depends on how much of the annual volume 

of runoff is diverted to the infiltration structure. On-line infiltration practices, on the other hand, 

have lower treatment effectiveness, averaging approximately 75 percent removal of TSS (WMI, 

1997b). 

The overall hydrologic benefits of infiltration practices may also vary depending on site 

characteristics and the frequency and intensity of storms. Holman-Dodds et al. (2003) modeled 

the potential for infiltration techniques to reduce the adverse hydrologic effects of urbanization. 

The study indicated that the greatest reductions in flow are achievable when rainfall is limited 

and relatively frequent, and when soils are relatively porous. 

Infiltration facilities require porous soils (i.e., sands and gravels) to function properly. Generally, 

they are not suitable in soils with 30 percent or greater clay content or 40 percent or greater 

silt/clay content (WMI, 1997b). They are also not suitable: 

— In areas with high water tables; 

— In areas with shallow depth to impermeable soil layers; 

— On fill sites, which have low permeability, or on steep slopes; 

— In areas where infiltration of runoff would likely contaminate ground water; 

— In areas where there is a high risk of hazardous material spills; or 

— Where additional groundwater could form sinkholes. 

Special protection for ground water is needed when runoff is used as a drinking water source in 

urban areas (see Management Measure 3—Watershed Protection). Certain types of infiltration 

facilities, called Class V injection wells, may be regulated as part of the federal Underground 

Injection Control (UIC) Program, authorized by the Safe Drinking Water Act. Class V wells 

discharge fluids underground. Class V wells include French drains, tile drains, infiltration sumps, 

and percolation areas with vertical drainage. Dry wells, bored wells, and infiltration galleries are 

all Class V wells. Class V wells do not include infiltration trenches filled with stone (with no 

piping), or excavated ponds, lagoons, and ditches (lined or unlined, without piping or drain tile) 

with an open surface. Compliance with federal regulations may include submitting basic 

inventory information about the drainage wells to the state or EPA and complying with specific 

construction, operation, permitting, and closure requirements (USEPA, 2003). Any questions 

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Management Measure 5: New Development Runoff Treatment 

regarding the applicability of the UIC regulations to a storm water facility should be directed to 

federal or state UIC contacts. This information is available at 

http://www.epa.gov/safewater/uic.html. 

The effect of infiltration practices on ground water quality is unclear, but a few studies exist that 

indicate potential ground water quality concerns from infiltrating urban runoff (Pitt, et al., 1994; 

Fischer, no date; Ging et al., 1997, Morrow, 1999). For example, Fischer (no date) studied the 

effects of infiltration of urban runoff on ground water quality in the New Jersey Coastal Plain. 

He found that although many pollutants were removed from runoff before reaching the water 

table, elevated concentrations and occurrences of certain compounds and ions indicated 

contributions from urban runoff, implying that infiltration practices could have a detrimental 

effect on ground water quality. Conversely, Fischer hypothesized that infiltrating runoff would 

have the beneficial effect of diluting other compounds frequently present in ground water. 

Pitt et al. (1994) summarized the potential for 25 pollutants to contaminate ground water, 

categorizing each as low, low/moderate, moderate, or high. Of these 25 pollutants, only one, 

chloride, has a high potential, and only fluoranthene and pyrene have a moderate potential. 

Nitrate, a highly soluble and mobile contaminant, was categorized as having a low/moderate 

potential for contamination, and the other 21 pollutants had low potential. 

Heavy metals and hydrocarbons may pose a low risk of contamination, but several studies have 

indicated that concentrations of these pollutants decrease rapidly with depth (Barraud et al., 

1999; Legret et al. 1999). Similarly, Dierkes and Geiger (1999) found that polycyclic aromatic 

hydrocarbons (PAHs) in highway runoff were removed in the top four inches of soil. 

The presence of volatile organic compounds (VOCs) in ground water is another concern. A 

USGS study (Ging et al., 1997) analyzed the occurrence and distribution of VOCs in ground 

water in south-central Texas. Although less than 50 percent of the samples taken had VOC 

detections, 28 VOCs were detected in samples from 89 wells. Based on the results of this study, 

VOC contamination in ground water appears to be associated with urban development (Ging et 

al., 1997). 

VOC contamination has also been detected in the ground water of the Lower Illinois River 

Basin. In 1996, water samples collected from 60 wells in the basin were sampled and analyzed 

for VOCs. There were only six VOC detections in more than 4,300 analyses of the ground water 

samples (although at least three of these detections may have been caused by well disinfection 

practices). Additionally, a VOC was detected in one sample from deep glacial drift, indicating 

that shallow aquifers may be more susceptible to VOC contamination than deep aquifers. Based 

on these results, the authors concluded that VOC contamination does not appear to be a major 

concern for ground water quality in rural areas of the Lower Illinois River Basin (Morrow, 

1999). 

Several studies have found that the potential for ground water contamination, particularly from 

heavy metals and hydrocarbons, is low when porous pavement and stone-filled subsurface 

infiltration beds are used. These systems provide treatment through adsorption, filtration, 

sedimentation, and biodegradation before runoff reaches the underlying soil (Balades et al., 

1995; Legret and Colandini, 1999; Newman et al., 2002; Pratt et al., 1999; Swisher, 2002). 

5-11 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

5.2.3.2 Filtration practices 

Filtration practices are so named because they filter particulate matter from runoff. The most 

common filtering medium is sand, but other materials, including peat/sand combinations and leaf 

compost material, have been used. Filtration systems provide only limited flood storage; 

therefore, they are most often implemented in conjunction with other types of quantity control 

management practices. Most filtration techniques require a forebay or clarifier to remove larger 

particles in runoff from clogging the filter media. 

Biofiltration refers to practices that use vegetation and amended soils to retain and treat runoff 

from impervious areas. Treatment is through filtration, infiltration, adsorption, ion exchange, and 

biological uptake of pollutants. 

5.2.3.3 Detention/retention practices 

Runoff detention facilities provide pollutant removal by temporarily capturing runoff and 

allowing particulate matter to settle prior to release to surface waters. Dry detention runoff 

management ponds are one type of detention facility. Peak flows are reduced in drainage 

systems/receiving waters downstream of detention facilities. 

Runoff retention facilities are used to capture runoff, which is subsequently withdrawn or 

evaporated. Therefore, peak flows and total flow volume can be reduced in downstream drainage 

systems/receiving waters. Wet runoff management ponds are one type of retention facility. These 

retention facilities can be designed to accept flow from receiving streams/drainage systems 

offline. 

Both detention and retention facilities can use biological uptake as a mechanism for pollutant 

removal. Runoff management ponds can be designed to control the peak discharge rates, thereby 

reducing excessive flooding and downstream erosion in reaches of the drainage system/receiving 

stream immediately downstream. At some point downstream, however, runoff flow that is not 

retained will increase the volume of total flow, thereby increasing the risk of flooding and 

erosion if the receiving stream at that point does not have a stable channel and riparian area or 

floodplain. 

Constructed wetlands are engineered systems designed to employ the water quality improvement 

functions of natural wetlands to treat and contain surface water runoff pollution and decrease 

pollutant loadings to surface waters. They can be designed with extended detention to control 

runoff peak flow and volume. Where site-specific conditions allow, constructed wetlands and 

retention basins should be located to minimize the impact on the surrounding areas (e.g., in 

upland areas of the watershed). Ponds, constructed wetlands, and other structural management 

practices degrade the functions of natural buffer areas and natural wetlands, and they may also 

interrupt surface water and ground water flow when soils are disturbed for installation. 

Therefore, the placement of structural management practices in natural buffers and natural 

wetlands should be avoided where possible. 

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Management Measure 5: New Development Runoff Treatment 

5.2.3.4 Evaporation practices 

Runoff detention and retention facilities and other practices that temporarily store runoff can also 

evaporate it. Evaporation from runoff detention and retention areas such as rooftops, streets, 

basins, and ponds can be an important mechanism for runoff management in warm, dry climates. 

5.3 Management Practices 

Management practices to control urban runoff can be classified in seven categories. The 

following practices are described for illustrative purposes only. EPA has found these practices to 

be representative of the types of practices that can be applied successfully to achieve the new 

development runoff treatment management measure. As a practical matter, EPA anticipates that 

the management measure can be achieved by applying one or more management practices 

appropriate to the source(s), location, and climate. Thus, practices that by themselves do not 

achieve 80 percent TSS removal can be combined with other practices to achieve 80 percent 

removal (such that x + y + z = 80 percent). This is the “treatment train” approach, in which 

several types of practices are used together and integrated into a comprehensive runoff 

management system (WMI, 1997b). The seven categories include: 

— Infiltration practices; 

— Vegetated open channel practices; 

— Filtering practices; 

— Detention ponds or vaults; 

— Retention ponds; 

— Wetlands; and 

— Other practices such as water quality inlets. 

5.3.1 Infiltration Practices 

These practices capture and temporarily store runoff before allowing it to infiltrate into the soil 

over several days. Design variants include: 

— Infiltration basins; 

— Infiltration trenches; and 

— Pervious or porous pavements. 

To prevent premature clogging, these practices must not receive drainage from a construction 

activity or site. Infiltration practices can be placed in service after the construction activity is 

complete or the site is stabilized. 

5.3.1.1 Infiltration basins 

Infiltration basins (Figure 5.1) are impoundments created by excavation or creation of berms or 

small dams. They are typically flat-bottomed with no outlet and are designed to temporarily store 

runoff generated from adjacent drainage areas (from 2 to 50 acres, depending on local 

conditions). Runoff gradually infiltrates through the bed and sides of the basin, ideally within 72 

hours, to maintain aerobic conditions and ensure that the basin is ready to receive runoff from the 

5-13 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

next storm. Infiltration basins are often used as an off-line system for treating the first flush of 

runoff flows or the peak discharges of the two-year storm. 

The key to successful operation is keeping the soils on the floor and side slopes of the basin 

unclogged to maintain the rate of percolation. This is usually much easier said than done. For 

example, Schueler (1992) reported infiltration basin failure rates ranging from 60 to 100 percent 

STILLING

BASIN

INFLOW

FLAT BASIN FLOOR WITH

GRASS TURF

BACKUP UNDERDRAIN

CONCRETE

LEVEL

SPREADER

GRASS CHANNEL

EMERGENCY

SPILLWAY

OUTFALL

RISER/

BARREL

INFLOW

STILLING BASIN

100 YEAR LEVEL

10 YEAR LEVEL

CPv OR 2 YEAR LEVEL

CLEANOUTS VALVE

RISER

EMBANKMENT

EMERGENCY

SPILLWAY

STABLE

OUTFALL

BARREL

ANTI-SEEP COLLAR or

FILTER DIAPHRAGM

BACKUP UNDERDRAIN PIPE IN CASE 

OF STANDING WATER PROBLEMS

INFILTRATION STORAGE

STILLING

BASIN

INFLOW

FLAT BASIN FLOOR WITH

GRASS TURF

BACKUP UNDERDRAIN

CONCRETE

LEVEL

SPREADER

GRASS CHANNEL

EMERGENCY

SPILLWAY

OUTFALL

RISER/

BARREL

INFLOW

STILLING BASIN

100 YEAR LEVEL

10 YEAR LEVEL

CPv OR 2 YEAR LEVEL

CLEANOUTS VALVE

RISER

EMBANKMENT

EMERGENCY

SPILLWAY

STABLE

OUTFALL

BARREL

ANTI-SEEP COLLAR or

FILTER DIAPHRAGM

BACKUP UNDERDRAIN PIPE IN CASE 

OF STANDING WATER PROBLEMS

INFILTRATION STORAGE

Figure 5.1: Schematic of an infiltration basin (MDE, 2000). 

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Management Measure 5: New Development Runoff Treatment 

in the mid-Atlantic region. To help keep sediment out of the basin, incoming runoff should be 

pretreated using vegetated filter strips, a settling forebay, or other techniques. Grasses or other 

vegetation should also be planted and maintained in the basin. If soil pores become clogged, the 

basin bottom should be roughened or replaced to restore percolation rates. 

5.3.1.2 Infiltration trenches 

Infiltration trenches (Figure 5.2) are shallow (2- to 10-feet deep) excavated ditches with 

relatively permeable soils that have been backfilled with stone to form an underground reservoir. 

The trench surface can be covered with a grating or can consist of stone, gabion, sand, or a grasscovered area with a surface inlet. Runoff diverted into the trench gradually infiltrates into the 

subsoil and, eventually, into the ground water. Trenches can be used on small, individual sites or 

for multi-site runoff treatment. Pretreatment controls such as vegetated filter strips should be 

incorporated into the design to remove sediment and reduce clogging of soil pores. More 

expensive than pond systems in terms of cost per volume of runoff treated, infiltration trenches 

are best-suited for drainage areas of less than 5 to 10 acres, or where ponds cannot be used. 

Variations in the design of infiltration trenches include dry wells, which are pits designed to 

control small volumes of runoff (such as rooftop runoff) and exfiltration trenches. A typical dry 

well design includes a perforated pipe 3 to 4 feet in diameter that is installed vertically in 

deposits of gravely/sandy soil. Rock is then backfilled around the base of the well. An 

exfiltration trench is an infiltration trench that stores runoff water in a perforated or slotted pipe 

and percolates it out into a surrounding gravel envelope and filter fabric. Dry wells and other 

infiltration practices that involve subsurface drainage may be regulated by EPA’s Underground 

Injection Control Program. See the EPA’s Underground Injection Control Program Web site at 

http://www.epa.gov/safewater/uic.html for more information. 

5.3.1.3 Pervious or porous pavements 

Pervious pavement has the approximate strength characteristics of traditional pavement but 

allows rainfall and runoff to percolate through it. The key to the design of these pavements is the 

elimination of most of the fine aggregate found in conventional paving materials. There are two 

types of pervious pavement, porous asphalt and pervious concrete (WMI, 1997b). Porous asphalt 

has coarse aggregate held together in the asphalt with sufficient interconnected voids to yield 

high permeability. Pervious concrete, in contrast, is a discontinuous mixture of Portland cement, 

coarse aggregate, admixtures, and water that also yields interconnected voids for the passage of 

air and water. Underlying the pervious pavement are a filter layer, a stone reservoir, and a filter 

fabric. Stored runoff gradually drains out of the stone reservoir into the subsoil. Figure 5.3 shows 

several types of porous pavement. More information about pervious pavement can be found at 

http://www.gcpa.org/pervious_concrete_pavement.htm (Georgia Concrete & Products 

Association, 2003). 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

PARKING LOT

BYPASS

(TO DETENTION FACILITY)

CONCRETE

LEVEL

SPREADER

STILLING

BASIN

GRASS

CHANNEL

(LESS THAN

1% SLOPE

OVERFLOW

INFILTRATION

TRENCH

WITH PEA GRAVEL

FILTER LAYER

OVER WASHED

BANK RUN GRAVEL

AGGREGATE

RUNOFF FILTERS THROUGH GRASS

BUFFER STRIP (20’ MINIMUM); GRASS

CHANNEL; OR SEDIMENT FOREBAY

2” PEA GRAVEL FILTER LAYER

PROTECTIVE LAYER OF FILTER FABRIC

TRENCH 3–8 FEET DEEP

FILLED WITH 1.5–2.5 INCH DIAMETER

CLEAN STONE

(BANK RUN GRAVEL PREFERRED)

SAND FILTER 6” DEEP

RUNOFF EXFILTRATES THROUGH

UNDISTURBED SUBSOILS WITH A

MINIMUM RATE OF 0.5 INCHES PER HOUR

OVERFLOW BERM

OVSERVATION 

WELL WITH 

SCREW TOP LID

PARKING LOT

BYPASS

(TO DETENTION FACILITY)

CONCRETE

LEVEL

SPREADER

STILLING

BASIN

GRASS

CHANNEL

(LESS THAN

1% SLOPE

OVERFLOW

INFILTRATION

TRENCH

WITH PEA GRAVEL

FILTER LAYER

OVER WASHED

BANK RUN GRAVEL

AGGREGATE

RUNOFF FILTERS THROUGH GRASS

BUFFER STRIP (20’ MINIMUM); GRASS

CHANNEL; OR SEDIMENT FOREBAY

2” PEA GRAVEL FILTER LAYER

PROTECTIVE LAYER OF FILTER FABRIC

TRENCH 3–8 FEET DEEP

FILLED WITH 1.5–2.5 INCH DIAMETER

CLEAN STONE

(BANK RUN GRAVEL PREFERRED)

SAND FILTER 6” DEEP

RUNOFF EXFILTRATES THROUGH

UNDISTURBED SUBSOILS WITH A

MINIMUM RATE OF 0.5 INCHES PER HOUR

OVERFLOW BERM

OVSERVATION 

WELL WITH 

SCREW TOP LID

Figure 5.2: Schematic of an infiltration trench (MDE, 2000). 

5-16 
Management Measure 5: New Development Runoff Treatment 

Figure 5.3: Photo showing several types of pervious modular pavement installations. 

Modular pavement consists of individual blocks made of pervious material such as sand, gravel, 

or sod interspersed with strong structural material such as concrete. The blocks are typically 

placed on a sand or gravel base and designed to provide a load-bearing surface that is adequate to 

support personal vehicles, while allowing infiltration of surface water into the underlying soils. 

They usually are used in low-volume traffic areas such as overflow parking lots and lightly used 

access roads. An alternative to pervious and modular pavement for parking areas is a geotextile 

material installed as a framework to provide structural strength. Filled with sand and sodded, it 

provides a completely grassed parking area. More information about concrete pavers can be 

found at http://www.concretenetwork.com/concrete/porous_concrete_pavers/

(Concretenetwork.com, 2003). 

Some states no longer promote the use of porous pavement because it tends to easily clog with 

fine sediments (Washington Department of Ecology, 1991). If this type of pavement is installed, 

a vacuum-type street sweeper should be used regularly to maintain porosity. Frequent washing 

with a high-pressure jet of water can also keep pores clear of clogging sediments. Sites where 

pervious pavement is to be installed must have deep, permeable soils, slopes of less than 

5 percent, and no heavy vehicle traffic. 

The City of Kinston, North Carolina, installed a permeable pavement parking lot as a 

demonstration and research project and to meet the daily parking needs of city employees (Hunt 

and Stevens, 2001). The final parking lot design included 26 stalls; 20 of the stalls were 

5-17 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

The Bath Club Concourse Storm Water Rehabilitation Project, Florida 

The Bath Club Concourse is located on a small barrier island community in North Redington Beach, 

Florida. A combination roadway and parking area, which connects Bath Club Circle and Gulf 

Boulevard, was previously an impervious slab of concrete pavement. The concourse could not absorb 

falling rain, which caused runoff to flow directly into a single storm sewer. The sewer would then carry 

pollutants directly to Boca Ciega Bay. In August 1990, the Water Management District and the town 

agreed to construct a stormwater rehabilitation project using pervious concrete pavement at the Bath 

Club Concourse (USEPA, 1999). 

The main objective of the rehabilitation project was to reduce nonpoint source pollutant loading by 

reducing the volume of runoff discharging directly into Boca Ciega Bay. A second objective was to 

demonstrate an innovative way to treat or improve the quality of runoff in highly urbanized areas, 

where it can sometimes be difficult or expensive to manage runoff because of land constraints. 

To maximize infiltration of runoff and reduce the amount of untreated runoff discharged directly into 

storm sewers, drainage was directed toward two pervious concrete parking areas. These areas were 

separated by an unpaved island in the center of the concourse, which also provides infiltration. 

Engineers installed two 150-foot under-drains to maximize infiltration by allowing subsurface soils to 

drain beneath the parking areas. 

The rehabilitation project resulted in a significant reduction of direct discharge of runoff from the site. 

Estimates indicate that these improvements resulted in a 33 percent reduction in total on-site runoff 

volume. Additionally, the volume of surface runoff discharging directly to Boca Ciega Bay was reduced 

by nearly 75 percent. Overall removal efficiencies for the project, which are based on the pollutant 

removal efficiency of the under-drain/filter system, indicate that the project can remove 73 percent of 

lead (Bateman et al., no date). Other removal efficiencies and additional information about the project 

are available at http://www.stormwaterauthority.org/assets/103BFloridaRetrofits.pdf. 

constructed using a concrete block paver filled with and overlaying sand, while the other six 

were constructed using a plastic grid paver with sandy soil and Bermuda grass. Monitoring 

results from a two-year study showed a 3- to 5-time reduction in peak runoff for storms greater 

than 0.5 inches based on calculated runoff coefficients (using the rational method). Of 

48 rainstorms, only 11 (less than 25 percent) resulted in runoff generated from the parking lot 

The researchers found that annual maintenance to scarify the surface of the lot with a street 

sweeper helps to maximize permeability of the pavement. More information about the study, 

including several design recommendations, can be found at 

http://www5.bae.ncsu.edu/programs/extension/wqg/issues/101.pdf. 

Brattebo and Booth (2003) examined the long-term effectiveness of permeable pavement by 

testing four commercially available permeable pavement systems for six years of regular parking 

use. The systems included the following: 

− A flexible plastic grid system with virtually no impervious area, filled with sand and 

planted with grass; 

− An equivalent plastic grid, filled with gravel; 

− A concrete block lattice with approximately 60 percent impervious coverage, filled with 

soil and planted with grass; and 

5-18 
Management Measure 5: New Development Runoff Treatment 

− Small concrete blocks with approximately 90 percent impervious coverage, with the 

spaces between blocks filled with gravel. 

At the end of the study, none of the systems showed major signs of wear. The pavements 

infiltrated nearly all rainwater, generating almost no surface runoff. The researchers compared 

the quality of infiltrated water to surface runoff from an asphalt area and found significantly 

lower levels of copper and zinc in the infiltrated water. Motor oil was not detected in infiltrated 

water but was detected in 89 percent of samples of surface runoff from asphalt. Measurements of 

infiltrated rainwater from five years earlier showed significantly higher concentrations of zinc 

and lower concentrations of copper and lead.

5.3.2 Vegetated Open Channel Practices 

Vegetated open channels are explicitly designed to capture and treat runoff through infiltration, 

filtration, or temporary storage. 

A vegetated swale is an infiltration practice that usually functions as a runoff conveyance 

channel and a filtration practice. It is lined with grass or another erosion-resistant plant species 

that serves to reduce flow velocity and allow runoff to infiltrate into ground water. The 

vegetation or turf also prevents erosion, filters sediment, and provides some nutrient uptake 

benefits. These practices are also known as biofiltration swales. Check dams are often used to 

reduce flow velocity. When used, sediment that collects behind check dams should be removed 

regularly. 

Two types of channels are typically used in residential landscapes: 

— Grass channels. These have dense vegetation, a wide bottom, and gentle slopes (Figure 

5.4). Usually they are intended to detain flows for 10 to 20 minutes, allowing sediments 

to filter out. 

— Dry swales. As with grass channels, runoff flows into the channel and is subsequently 

filtered by surface vegetation (Figure 5.5). From there, runoff moves downward through 

a bed of sandy loam soil and is collected by an underdrain pipe system. The treated water 

is delivered to a receiving water or another structural control. Dry swales are used in 

large-lot, single-family developments and on campus-type office or industrial sites. They 

are applicable in all areas where dense vegetative cover can be maintained. Because of a 

limited ability to control runoff from large storms, they are often combined with other 

structural practices. They should not be used in areas where flow rates exceed 1.5 feet per 

second unless additional erosion control measures, such as turf reinforcement mats, are 

used. 

5-19 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Figure 5.4: Schematic of a grass channel (Claytor and Schueler, 1996). 

5-20 
Management Measure 5: New Development Runoff Treatment 

In a research study conducted by J.F. Sabourin and Associates (1999), two grass 

swale/perforated pipe systems and one conventional curb-and-gutter system were compared. 

Flow monitoring results indicate that much less water reached the outlet of the perforated pipe 

systems than the conventional system. Peak flows and total runoff volumes from the outlet of the 

perforated pipe/grass swale system were 2 to 6 percent of those of the conventional system, and 

total runoff volumes were 6 to 30 percent of conventional system volumes. Water quality 

monitoring results indicate that for most elements, concentrations measured in the perforated 

pipes were the same or lower than in the conventional system. Chloride concentrations were 

found to be higher in the perforated pipe system, most likely from the use of road salt. However, 

a loading analysis indicated that the perforated pipes released significantly fewer pollutants than 

the conventional system. 

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j j j j j j j j j 

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CHECK DAM

ROAD

PRETREATMENT

SIDE SLOPE

PRETREATMENT

FOREBAY

INFLOW

RIPRAP

SHOULDER

CHANNEL BOTTOM

10-YEAR STORM

2-YEAR STORM

WATER QUALITY STORM

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CHECK DAM

ROAD

PRETREATMENT

SIDE SLOPE

PRETREATMENT

FOREBAY

INFLOW

RIPRAP

CHANNEL BOTTOM

SHOULDER

10-YEAR STORM

2-YEAR STORM

WATER QUALITY STORM

Figure 5.5: Schematic of a dry swale (adapted from MDE, 2000). 

5-21 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

The authors also performed video inspections of the swale/perforated pipe sewershed. These 

inspections revealed a few interesting issues that can affect the performance of perforated pipe 

systems. Several unauthorized sanitary sewer connections had been made by some residents, and 

several raccoons were found living inside the pipes. Both can contribute to nutrient and pathogen 

problems in receiving waters. 

J.F. Sabourin and Associates concluded that infiltration capacities of grass swales are optimum 

when they allow for proper drainage and hold enough moisture for sustaining grass and plant 

life. Exfiltration tests indicated that runoff volumes can be reduced by 40 to 60 percent by grass 

swales and perforated pipe drainage systems. With a direct connection, peak outflows can be 

45 percent of the inflow. 

5.3.3 Filtering Practices 

Filtering practices capture and temporarily store runoff and pass it through a filter bed of sand, 

organic matter, soil, or other media. Filtered runoff may be collected and returned to the 

conveyance system, or allowed to exfiltrate into the soil. Design variants include: 

— Surface sand filter; 

— Underground sand filter; 

— Organic filter; 

— Pocket sand filter; and 

— Bioretention areas. 

5.3.3.1 Filtration basins and sand filters 

Filtration basins are impoundments lined with a filter medium such as sand or gravel. Runoff 

drains through the filter medium and through perforated pipes into the subsoil. Detention time is 

typically four to six hours. Sediment-trapping structures are often used to prevent premature 

clogging of the filter medium (NVPDC, 1980; Schueler et al., 1992). 

Sand filters are usually two-chambered practices: the first is a settling chamber and the second is 

a filter bed filled with sand or another filtering medium. As runoff flows into the first chamber, 

large particles settle out and finer particles and other pollutants are removed as runoff flows 

through the filtering medium. There are several modifications of the basic sand filter design, 

including the surface sand filter, underground sand filter, perimeter sand filter, organic media 

filter, and multi-chambered treatment train (Robertson et al., 1995). All of these filtering 

practices operate on the same basic principle. Modifications to the traditional surface sand filter 

were made primarily to fit sand filters into more challenging site designs (e.g., underground and 

perimeter filters) or to improve pollutant removal (e.g., organic media filter). The following are 

design variations for sand filtration devices: 

(1) Surface sand filter. The surface sand filter (Figure 5.6) is an aboveground filter design. Both 

the filter bed and the sediment chamber are aboveground. The surface sand filter is designed 

as an off-line practice; only the water quality volume is directed to the filter. The surface 

sand filter is the least-expensive filter option and has been the most widely used. 

5-22 
Management Measure 5: New Development Runoff Treatment 

(2) Underground sand filter. The underground sand filter (Figure 5.7) is a modification of the 

surface sand filter, where all of the filter components are underground. Like the surface sand 

filter, this practice is an off-line system that receives only flows from small rainstorms. 

Underground sand filters are expensive to construct but consume very little space. They are 

well-suited to highly urbanized areas, and often included in groups of practices known as 

“ultra-urban BMPs.” 

(3) Perimeter sand filter. The perimeter sand filter (Figure 5.8) also includes the basic design 

elements of a sediment chamber and a filter bed. In this design, however, flow enters the 

system through grates, usually at the edge of a parking lot. The perimeter sand filter is the 

only filtering option that is on-line; all flow enters the system, but a bypass to an overflow 

chamber prevents system flooding. One major advantage of the perimeter sand filter design is 

that it requires little hydraulic head and thus is a good option in areas of low relief. 

(4) Organic media filter. Organic media filters (Figure 5.9) are essentially the same as surface 

filters, with the sand replaced with or supplemented by another medium. Two examples are 

the peat/sand filter (Galli, 1990) and the compost filter system. It is assumed that these 

systems will provide enhanced pollutant removal for many compounds because of the 

increased cation exchange capacity achieved by increasing organic matter content. 

(5) Multi-chambered treatment train. The multi-chambered treatment train (Figure 5.10) is 

essentially a “deluxe sand filter” (Robertson et al., 1995). This underground system consists 

of three chambers. Runoff enters into the first chamber where screening occurs, trapping 

large sediments and releasing highly volatile materials. The second chamber provides settling 

of fine sediments and further removal of volatile compounds and floatable hydrocarbons 

through the use of fine bubble diffusers and sorbent pads. The final chamber provides 

filtration by using a sand and peat mixed medium for reduction of the remaining pollutants. 

The top of the filter is covered by a filter fabric that evenly distributes the water volume and 

prevents channelization. Although this practice can achieve very high pollutant removal 

rates, it might be prohibitively expensive in many areas. It has been implemented only on an 

experimental basis. 

(6) Exfiltration/partial exfiltration. In exfiltration designs, all or part of the underdrain system is 

replaced with an open bottom that allows infiltration to the ground water. When the 

underdrain is present, it is used as an overflow device in case the filter becomes clogged. 

These designs are best applied in the same soils where infiltration practices are used. 

5-23 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Figure 5.6: Schematic of a surface sand filter (MDE, 2000). 

5-24 
Management Measure 5: New Development Runoff Treatment 

Figure 5.7: Schematic of an underground sand filter (MDE, 2000). 

5-25 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Figure 5.8: Schematic of a perimeter sand filter (MDE, 2000). 

5-26 
Management Measure 5: New Development Runoff Treatment 

Figure 5.9: Schematic of an organic media filter (MDE, 2000). 

5-27 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

SORBENT PADS

FINE BUBBLE

AERATOR

FILTER FABRIC

GRAVEL UNDERDRAIN PERFORATED PVC PIPE

PEAT/SAND MEDIUM

OUTFLOW

INFLOW

INLET/

SCREENING SETTLING FILTRATION

INCLINED TUBE/

PLATE SETTLERS

FLASH

AERATOR SORBENT PADS

FINE BUBBLE

AERATOR

FILTER FABRIC

GRAVEL UNDERDRAIN PERFORATED PVC PIPE

PEAT/SAND MEDIUM

OUTFLOW

INFLOW

INLET/

SCREENING SETTLING FILTRATION

INCLINED TUBE/

PLATE SETTLERS

FLASH

AERATOR

Figure 5.10: Schematic of a multi-chambered treatment train (Pitt, 1996). 

5.3.3.2 Media filtration units 

Similar to wastewater treatment technology, passive filtration units can be used to capture 

pollutants from runoff. Media filtration practices commonly use trenches filled with sand or peat. 

Other media, including types of crushed rock and composted leaves, can also be used. A basin 

collects the runoff and gradually routes discharge through cartridges filled with filter media. An 

emergency bypass prevents system flooding during large rainstorms. According to the Unified 

Sewerage Agency of Washington County in Oregon (WEF, 1998), composted leaf media trap 

particulates, adsorb organic chemicals, and remove 90 percent of solids, 85 percent of oil and 

grease, and 82 to 98 percent of heavy metals through cation exchange from leaf decomposition. 

Similar types of systems with various filter media are available commercially. 

5-28 
Management Measure 5: New Development Runoff Treatment 

Performance of a Compost Storm Water Treatment System in Hillsboro, Oregon 

A compost storm water treatment facility was constructed to treat runoff from 3.9 acres of 5-lane 

arterial road and 70.1 acres of mixed residential land use in Hillsboro, Oregon (FHWA, no date). The 

system consists of a discharge pipe that conveys runoff from the drainage area into a forebay. Runoff 

then flows over a wooden baffle into two consecutive cells filled with Portland leaf compost material. 

After runoff filters through the compost medium, it is discharged to a rock drainbed separated from the 

compost by a layer of filter fabric. 

Monitoring of the effluent between 1991 and 1994 showed average mass balance pollutant removals 

of 81 percent for oils and grease, 84 percent for petroleum hydrocarbons, 58 percent to 94 percent for 

nutrients, and 68 percent to 93 percent for metals. See Table 5.4 for additional pollutant removal 

results. More details on the design and performance of this study are available at 

http://www.fhwa.dot.gov/environment/ultraurb/5mcs5.htm. 

Table 5.4: Pollutant removal efficiencies for the compost storm water treatment facility from 

1991 to 1994.

Parameter 1991-1992 1992-1993 1993-1994 

Turbidity Combined 84.2 % 78.4 % 78.4 % 

First Flush 93.4 % 85.3 % 81.4 % 

5.3.3.3 Bioretention systems 

Bioretention systems (Figure 5.11 and Figure 5.12) are suitable to treat runoff on sites where 

there is adequate soil infiltration capacity and where the runoff volumes that are not infiltrated do 

not present a safety or flooding hazard. Typical applications for bioretention include parking 

areas with or without curbs, traffic islands, and swales or depressed areas that receive runoff 

from impervious areas. 

Total Suspended Solids Combined 94.8 % 88.5 % 86.0 % 

First Flush 98.3 % 91.4 % 89.0 % 

Chemical Oxygen Demand Combined 66.9 % 76.3 % 74.0 % 

First Flush 89.5 % 82.1 % 79.8 % 

Total Phosphorus Combined 40.5 % 53.2 % 65.5 % 

First Flush 67.3 % 68.9 % 72.9 % 

Total Kjeldhal Nitrogen Combined 55.9 % 50.5 % 66.7 % 

First Flush 84 % 60.8 % 69.0 % 

Iron Combined 89 % 95.5 % 79.6 % 

First Flush 94 % 97.5 % 82.9 % 

Chromium Combined 61.2 % 74.5 % 64.3 % 

First Flush 92.4 % 80.8 % 72.8 % 

Copper Combined 66.7 % 63.5 % 64.1 % 

First Flush 83.7 % 73.9 % 70.7 % 

Lead Combined N/A 85.1 % 81.4 % 

First Flush N/A 89.0 % 84.0 % 

Zinc Combined 88.3 % 75.8 % 79.9 % 

First Flush 92.8 % 83.1 % 83.1 % 

5-29 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Bioretention system designs are very flexible, can be adapted to a wide range of commercial, 

industrial, and residential settings, and can be linked in series or combined with structural 

devices to provide the necessary level of treatment depending on expected runoff volumes and 

pollutant loading. A common technique is to use bioretention areas to pre-treat sheet flow before 

it is channelized or collected in an inlet structure. 

Figure 5.11: Schematic of a bioretention system (MDE, 2000). 

5-30 
Management Measure 5: New Development Runoff Treatment 

Side View

(not to scale)

Concrete Potting Soil Pavement Grass

4 ft

El 447.75

El 

445.0

Concrete splash

block

Invert

(El 444.25)

El 

444.0

Cut in curb

(El 446.0)

Side View

(not to scale)

Potting Soil

Seal off 

Weir inlet

El 445.20

Concrete Potting Soil Pavement Grass

4 ft

El 447.75

El 

445.0

Concrete splash

block

Invert

(El 444.25)

El 

444.0

Cut in curb

(El 446.0)

Seal off 

Weir inlet

El 445.20

4 ft

El 447.75

El 

445.0

Concrete splash

block

Invert

(El 444.25)

El 

444.0

Cut in curb

(El 446.0)

Seal off 

Weir inlet

El 445.20

Figure 5.12: Schematic of a bioretention parking lot island (Traver, 2003). 

5-31 

Bioretention should not be used in areas: 

— With mature trees; 

— With slopes greater than 20 percent; 

— With a water table within 6 feet of the land surface; 

— With easily erodible soils; 

— Below outfalls; 

— Where concentrated flows are discharged; or 

— Where excavation or cutting will occur. 

To determine the appropriate design of the bioretention area with respect to the amount of runoff 

it receives, Prince George’s County, Maryland, Department of Environmental Resources (1993), 

suggests a design based on a four-day maximum ponding period (appropriate for the MidAtlantic region). This four-day period is based on hydrologic, horticultural, and maintenance 

constraints such as plant tolerance of flooded conditions and mosquito-breeding concerns. Other 

considerations include infiltration rates for the root zone, sand layer, and in-situ material. 

There is some flexibility with respect to size, shape, and placement of vegetation within the 

bioretention area. Other elements that should be incorporated into the design of the bioretention 

system include curb openings, a ponding area suitable to handle runoff from larger storms, 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

amended planting soil that provides the desired infiltration rate, and an under-layer sand or 

gravel bed or underground perforated pipe that facilitates infiltration. 

Regular maintenance, including soil pH testing, mulching and repairing eroded areas, inspecting 

vegetation, ensuring that runoff is infiltrating as designed, and checking for damage caused by 

large storms, will help to ensure the longevity of bioretention areas. More information about the 

design, operation, and maintenance of bioretention systems can be found in Coffman and 

Winogradoff (1999) or Prince George’s County, Maryland, Department of Environmental 

Resources (1993). 

As for the performance of bioretention areas, in one research study, simulated runoff was 

pumped continuously into an area of 5.3 m2 in six bioretention cells, and effluent samples were 

collected from the perforated drainpipes underlying the bioretention media. All six bioretention 

facilities showed greater than 99 percent removal efficiency for oil and grease. Total lead 

removal efficiency decreased when the TSS level in the effluent increased because lead was 

adsorbed onto the surface of the solids. TSS removal ranged from 72 to 99 percent, and lead 

removal rates ranged from 80 to 100 percent. For total phosphorus, the removal efficiency was 

found to be highly variable, ranging from 37 to 99 percent. Nitrate-nitrogen and ammoniumnitrogen removal efficiencies ranged from 2 to 7 percent and 5 to 49 percent, respectively. 

Overall, the bioretention cells contributed significantly to water quality improvement (Hsieh and 

Davis, 2003). 

The developer of Somerset Community, a typical suburban development in Prince George’s 

County, Maryland, incorporated bioretention areas into each lot to control runoff quantity and 

quality. The bioretention areas eliminated the need for a wet pond, allowed the development of 

six extra lots, and resulted in a cost savings of more than $4,000 per lot. Somerset residents have 

enthusiastically accepted their bioretention areas, are actively maintaining them, and have lodged 

few complaints. Safety issues and mosquitoes have not been a problem (Daniels, 1995, and 

Curry and Wynkoop, 1995). 

The Inglewood Demonstration Project in Largo, Maryland, involved retrofitting an existing 

parking facility with bioretention areas and comparing the pollutant removal efficiency of a 

bioretention cell in a laboratory setting to that of a comparable facility constructed in a parking 

lot. This study showed the feasibility of retrofitting an existing parking facility and demonstrated 

the consistency of laboratory and field pollutant removal performance. Results showed that the 

runoff temperature was lowered 12 degrees Celsius, lead levels were lowered 79 percent, zinc 

levels were lowered 78 percent, and numerous other pollutant levels were also considerably 

reduced. The retrofit cost $4,500 to construct, while usual methods would have cost $15,000 to 

$20,000 and involved fewer environmental benefits and higher maintenance costs. Also, 

bioretention areas offer the ancillary benefit of aesthetic enhancement. It is interesting to note 

that a drought occurred after the installation of the plants, and although many of the other plants 

in the parking lot died or experienced severe drought stress, those in the bioretention facility 

survived because of the retained water supply (USEPA, 2000a). 

5-32 
Management Measure 5: New Development Runoff Treatment 

Using Landscaped Rain Gardens to Control Runoff

The city of Maplewood, Minnesota is seeking to improve drainage in its older neighborhoods through 

the use of rain gardens. A successful pilot project, which was implemented in 1995, was the starting 

point for the current citywide rain garden initiative. Rain gardens from the pilot project have prevented 

runoff from flowing out of the area, containing 100 percent of the flow. City officials decided to expand 

the project when they recognized the aesthetic and environmental benefits resulting from the pilot 

project rain gardens. 

The city is focusing on demonstration, education, and outreach to convey the benefits of using rain 

gardens for runoff management, rather than requiring homeowners to participate. Although rain 

gardens can be a solution for people who are opposed to adding curbs and gutters to their streets, 

some are concerned that rain gardens may attract and breed mosquitoes. Before beginning a street 

improvement project for a specific neighborhood, the city holds neighborhood meetings and distributes 

a comprehensive educational mailing and questionnaire to homeowners. These materials contain a 

fact sheet that explains the purpose of rain gardens, how they are designed, how they work, their 

benefits, and the plants best suited for a variety of hydrologic conditions. A questionnaire is also 

included to ascertain existing drainage problems and to determine whether the homeowner would be 

willing to agree to use a rain garden. 

Once a homeowner has decided that they want a rain garden, they choose the location and size. The 

city works with homeowners to make these types of decisions and to help them comply with 

restrictions on garden placement caused by existing trees, natural drainage, or the presence of gas 

and water mains and other utilities. Homeowners may choose from three standard rain garden sizes 

(12-foot by 24-foot, 10-foot by 20-foot, and 8-foot by 16-foot) and from one of six different garden 

themes, including an easy shrub garden, easy daylily garden, sunny garden, sunny border garden, 

butterflies and friends garden, Minnesota prairie garden, and shady garden. 

To begin construction, the city’s contractor excavates a gently sloping depression to collect the water. 

Rain garden depths vary depending on garden size and topography. The contractor digs a sump 42 

inches wide and 3 feet deep at the deepest part of the garden to accommodate a geotextile filter fabric 

bag, which is filled with clean crushed rock. The sump promotes rapid infiltration to reduce the 

standing time of water in the rain garden. After the infiltration sump is in place, the contractor adds at 

least 8 inches of bedding material (typically a mixture of salvaged topsoil and clean organic compost) 

and covers the area with 3 to 4 inches of shredded wood mulch. Residents are provided with all 

necessary plants and a landscape plan at no additional cost. However, many Minnesota municipalities 

charge residents a street assessment to cover a percentage of the project cost. 

The city’s rain garden street improvement project typically costs 75 to 85 percent of a traditional curb 

and gutter project. Costs are kept low because most of the existing street material is recycled to use 

as the base aggregate. Additionally, plants are obtained at a reasonable cost and residents are 

responsible for the planting. Other long-term savings, which are difficult to quantify, result from the 

reduced demand on the city’s downstream sewer infrastructure, which is not characteristic of 

conventional storm systems. The city may also be able to reduce the need for downstream storm 

sewer system upgrades and construction, including detention and treatment facilities designed to 

prevent pollution, erosion, and flooding problems. 

More information about Maplewood’s rain garden project is available from Chris Cavett, Assistant City 

Engineer, at 651-770-4554 or chris.cavett@ci.maplewood.mn.us (Terrene Institute, 2001). 

5-33 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

5.3.4 Detention and Retention Practices 

5.3.4.1 Detention ponds and vaults 

These practices temporarily detain runoff to ensure that the postdevelopment peak discharge rate 

is equal to the predevelopment rate for the desired design storm (e.g. two-, 10-, or 25-year). 

These practices may also be used to provide temporary extended detention to protect 

downstream channels from erosion (e.g., 24-hour extended detention for a one-year storm). 

Extended detention (ED) ponds (Figure 5.13) are an example of this type of facility. ED ponds 

temporarily detain a portion of urban runoff for up to 24 hours after a storm, using a fixed orifice 

to regulate outflow at a specified rate and allowing solids and associated pollutants time to settle 

out. ED ponds are normally dry between storm events and do not have any permanent standing 

water. These basins are typically composed of two stages: an upper stage, which remains dry 

except after larger storms, and a lower stage, which is designed for typical storms. Enhanced ED 

ponds are equipped with plunge pools or forebays near the inlet, a micropool at the outlet, and an 

adjustable reverse-sloped pipe as the ED control device (NVPDC, 1980; Schueler et al., 1992). 

Most ED ponds use a riser with an anti-vortex trash rack on top to control large floating solids. 

Detention tanks and vaults are underground structures used to control peak runoff flows. They 

are usually constructed out of concrete (vaults) or corrugated metal pipe (tanks). Underground 

detention can also be achieved by retrofitting the over-capacity storm drain pipes with baffles. 

The baffles allow water to be stored in the pipes so it can be released at a slower rate. 

Pretreatment structures such as water quality inlets and sand filters can be used to treat runoff 

and remove trash and debris. 

These systems are primarily applicable where space is limited and there are no other practical 

alternatives. Concrete vaults are relatively expensive and are often used to control small flows 

where system replacement costs are high. Corrugated metal pipe systems are less expensive and 

are often used to control larger volumes of runoff in parking lots, adjacent to rights-of-way, and 

in medians. These systems should be located where maintenance can be conducted with minimal 

disturbance. 

Underground detention structures provide runoff quantity control but do not provide significant 

water quality control without modifications. Corrugated metal pipe systems can work in 

conjunction with infiltration to provide additional runoff treatment. This is accomplished by 

adding perforations to the pipe to allow it to store the water until it can be released into the soil 

(FHWA, no date). 

5.3.4.2 Retention ponds 

These practices use a permanent pool, extended detention basin, or shallow marsh to remove 

pollutants and can include: 

— Micropool extended detention ponds; 

— Wet ponds; 

— Wet extended detention ponds; and 

— Multiple pond systems. 

5-34 
Management Measure 5: New Development Runoff Treatment 

MAXIMUM ELEVATION

OF 100-YR STORM

MAXIMUM ELEVATION

OF ED POOL

INFLOW

PILOT CHANNEL

EXISTING 

VEGETATION RETAINED

EMERGENCY

SPILLWAY

OUTFALL

MICROPOOL

FOREBAY

SAFETY

BENCH

AQUATIC

BENCH

MAINTENANCE ACCESS TO MICROPOOL

Qp LEVEL

Qf LEVEL

Cpv LEVEL

ED LEVEL

INFLOW

FOREBAY

MICROPOOL

ANTI-SEEP COLLAR or

FILTER DIAPHRAGM

STABLE

OUTFALL

EMERGENCY

SPILLWAY

EMBANKMENT

RISER

HOOD

BARREL

MAXIMUM ELEVATION

OF 100-YR STORM

MAXIMUM ELEVATION

OF ED POOL

INFLOW

PILOT CHANNEL

EXISTING 

VEGETATION RETAINED

EMERGENCY

SPILLWAY

OUTFALL

MICROPOOL

FOREBAY

SAFETY

BENCH

AQUATIC

BENCH

MAINTENANCE ACCESS TO MICROPOOL

Qp LEVEL

Qf LEVEL

Cpv LEVEL

ED LEVEL

INFLOW

FOREBAY

MICROPOOL

ANTI-SEEP COLLAR or

FILTER DIAPHRAGM

STABLE

OUTFALL

EMERGENCY

SPILLWAY

EMBANKMENT

RISER

HOOD

BARREL

Figure 5.13: Schematic of a dry extended detention pond (MDE, 2000). 

Ponds (Figure 5.14) are basins designed to maintain a permanent pool of water and temporarily 

store runoff (ED wet pond), which is released at a controlled rate. Ponds allow particulates to 

settle and can provide biological uptake of pollutants such as nitrogen or phosphorus. Enhanced 

designs include a forebay to trap incoming sediment where it can easily be removed. Often, a 

5-35 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

POND BUFFER

(25 FEET MINIMUM)

OVERFLOW

SPILLWAY 

HARDENED

PAD FOREBAY

MAINTENANCE

ACCESS ROAD

NATIVE LANDSCAPING AROUND POOL

SAFETY BENCH

AQUATIC BENCH

RISER/

BARREL

RISER IN 

ENBANKMENT

OUTFALL

EMERGENCY

SPILLWAY 

INFLOW IRREGULAR POOL SHAPE

6-8 FEET DEEP 

BE

R

100 YEAR LEVEL

10 YEAR LEVEL

Cpv OR 2 YEAR LEVEL

INFLOW

FOREBAY

AQUATIC

BENCH 

WET POOL

SAFETY

BENCH

EMBANKMENT

RISER

STABLE

OUTFALL

EMERGENCY

SPILLWAY 

ANTI-SEEP COLLAR or

FILTER DIAPHRAGM 

REVERSE PIPE

POND DRAIN

BARREL

25

Figure 5.14: Schematic of a wet pond (MDE, 2000). 

fringe wetland is installed around the perimeter of the pond to increase the habitat, aesthetic, and 

pollutant removal values of the facility. An outlet riser, sometimes combined with an anti-vortex 

trash device, is a common design modification. The design of wet ponds should account for the 

infiltration of ground water when the wet pond intercepts the water table. Table 5.5 presents 

several design considerations for ponds. 

5-36 
Management Measure 5: New Development Runoff Treatment 

Table 5.5: Design considerations for ponds and wetlands (MDE, 2000). 

Design Consideration Ponds Wetlands 

Watershed Design Requirements

Streams in intensely 

developed areas 

Drainage area may limit the applicability 

of ponds except for pocket ponds. 

Drainage area may limit the applicability 

of ponds except for pocket wetlands. 

Cold-water streams An offline design is recommended. 

Maximize shading of open pool areas. 

An off-line design is recommended. 

Maximize shading of open pool areas. 

Streams in sparsely 

developed areas 

Require additional storage to ensure 

adequate downstream channel protection. 

Require additional storage to ensure 

adequate downstream channel protection. 

Aquifer protection May require a liner depending on soil type. May require a liner depending on soil type. 

Reservoir protection Require additional storage to ensure 

adequate downstream channel protection. 

Require additional storage to ensure 

adequate downstream channel protection. 

Shellfish beach located 

downstream 

Provide moderate bacteria removal. Should 

be designed to prevent geese problems. 

Should provide permanent pools. 

Provide 48-hr extended detention for 

maximum bacterial die-off. 

Terrain Factors

Low relief The maximum normal pool depth should 

be 4 feet (dugout). 

Wetlands are suitable for low-relief areas. 

Karst Require a poly or clay liner and 

geotechnical tests. 

Require a poly or clay liner and 

geotechnical tests. 

Mountainous Embankment heights are restricted. Embankment heights are restricted. 

Physical Feasibility

Soils Depending on pond type, they may or may 

not require a liner or testing. 

Certain soils may require a liner. 

Water table Must be at least 2 feet above water table if 

near a potentially contaminated “hotspot” 

or if underlain by an aquifer. Pocket ponds 

by definition are below the water table. 

Must be at least 2 feet above water table if 

near a potentially contaminated “hotspot” 

or if underlain by an aquifer. 

Drainage area Minimum drainage area is 10 to 25 acres 

depending on type of pond. Pocket pond 

has a 5-acre maximum. 

Minimum of 25 acres except pocket 

wetlands, which have a 5-acre maximum. 

Site slope Slopes should always be less than 15% Slopes should be less than 8%. 

Head A 6- to 8-foot head is needed for all ponds 

except pocket ponds, which require a 4-

foot head. 

A 3- to 5-foot head is needed for most 

wetlands except pocket wetlands, which 

require a 2- to 3-foot head. 

Ultra urban Only pocket ponds are practical. Pocket wetlands are sometimes practical; 

all others impractical. 

Runoff Treatment Suitability

Ground water recharge No No 

Channel protection Yes Yes 

Runoff Treatment Suitability (continued)

Ground water recharge No No 

Channel protection Yes Yes 

Water quantity control Yes Yes 

Large space 

requirements 

Less space More space 

Community and Environmental Factors

Maintenance Easier More difficult 

Community acceptance More acceptable Less acceptable 

Affordability More affordable Less affordable 

Wildlife habitat Yes Yes

5-37 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Used in combination with on-site and nonstructural practices, regional ponds are an important 

component of a runoff management program. The costs and benefits of regional, or off-site, 

practices compared to on-site practices should be considered as part of a comprehensive 

management program. For example, regional ponds can be located to treat runoff from existing 

development, and will result in overall net reductions on pollutant loads for the watershed 

(Fairfax County Environmental Coordinating Committee, 2002). Regional facilities can 

incorporate more advanced treatment technologies than on-site facilities (Maupin and Wagner, 

2003). They can also provide community recreation and wildlife benefits, reduce peak and total 

flow, and be easier to maintain than dispersed controls. The City of Fairfax, Virginia, found that 

maintenance costs for a regional pond were about one-sixth those of on-site ponds (Fairfax 

County Environmental Coordinating Committee, 2002). Maintenance responsibilities and 

liability for regional runoff facilities belong to the municipality (Maupin and Wagner, 2003). 

A study of 43 wadeable streams in Austin, Texas, showed that several indicators of stream health 

(ephemeroptera-plecoptera-trichoptera (EPT) richness and percent EPT abundance) were higher 

in streams with storm water ponds protecting 60 to 95 percent of their catchments than in streams 

with no storm water controls (Maxted and Scoggins, 2004). This trend was only significant in 

fully developed watersheds (having greater than 40 percent impervious cover). In watersheds 

with less than 40 percent impervious cover, storm water ponds had no significant impact on EPT 

richness or percent EPT abundance. The researchers attributed the lack of effects of storm water 

ponds to urban development in the reference watersheds and to the nature of the biological index 

used to gauge stream health, which was not tailored to the specific environmental conditions of 

the Austin area. 

Research has shown that storm water ponds can increase property values. A survey in Columbia, 

Maryland, found that 75 percent of homeowners felt that permanent bodies of water such as 

storm water ponds added to real estate values. Seventy-three percent were willing to pay more 

for property located in a neighborhood with storm water control basins designed to enhance fish 

or wildlife uses (Adams et al., 1984; Tourbier and Westmacott, 1992; USEPA, 1995). Residents 

of a Champaign-Urbana, Illinois, neighborhood with storm water ponds stated that lots adjacent 

to a wet pond were worth an average of 21.9 percent more than comparable non-adjacent lots in 

the same subdivision. The same survey revealed that 82 percent would in the future be willing to 

pay a premium for a lot adjacent to a wet pond (Emmerling-DiNovo, 1995). In Alexandria, 

Virginia, condominiums alongside a 14-acre runoff detention pond sold for $7,500 more than 

comparable units not adjacent to the pond (USEPA, 1995). 

Regional ponds do not, however, provide protection in contributing drainage systems, including 

upstream tributaries. These can experience damage from increased peak flow and flow volume. 

In addition, placement of regional ponds in low-lying areas may harm natural wetlands, and the 

ponds may create safety and liability issues. Siting ponds or other structural management 

practices within natural buffer areas and wetlands degrades their functions and may interrupt 

surface water and ground water flow when soils are disturbed for installation. 

5.3.4.3 Constructed wetlands 

Constructed wetlands (Figure 5.15) are engineered systems designed to treat runoff. They are 

typically designed to provide some of the functions of natural wetlands, e.g., wildlife habitat, in 

5-38 
Management Measure 5: New Development Runoff Treatment 

WETLAND BUFFER

(25 FEET MINIMUM) LIMIT 25% OF POND

PERIMETER OPEN GRASS

25’

SAFETY BENCH

EMERGENCY

SPILLWAY

OUTFALL

RISER/

BARREL

RISER IN

EMBANKMENT

HIGH MARSH

(LESS THAN 6” WATER DEPTH) LOW MARSH

(WATER DEPTH BETWEEN 6” AND 18”)

25’ WETLAND BUFFER LANDSCAPED WITH

NATIVE TREES/SHRUBS FOR HABITAT

MAINTENANCE

ACCESS ROAD

INFLOW

FOREBAY

WEIR

WALL

WATERFOWL

ISLAND

MICROPOOL

25’

WETLANDS

HIGH MARSH

100 YEAR LEVEL

10 YEAR LEVEL

Cpv OR 2 YEAR LEVEL

WQv LEVEL

INFLOW

FOREBAY

GABION WALL

LOW MARSH

POND DRAIN

REVERSE PIPE

BARREL

RISER

EMBANKMENT

EMERGENCY

SPILLWAY

STABLE

OUTFALL

ANTI-SEEP COLLAR or

FILTER DIAPHRAGM

PERMANENT

POOL

WETLAND BUFFER

(25 FEET MINIMUM) LIMIT 25% OF POND

PERIMETER OPEN GRASS

25’

SAFETY BENCH

EMERGENCY

SPILLWAY

OUTFALL

RISER/

BARREL

RISER IN

EMBANKMENT

HIGH MARSH

(LESS THAN 6” WATER DEPTH) LOW MARSH

(WATER DEPTH BETWEEN 6” AND 18”)

25’ WETLAND BUFFER LANDSCAPED WITH

NATIVE TREES/SHRUBS FOR HABITAT

MAINTENANCE

ACCESS ROAD

INFLOW

FOREBAY

WEIR

WALL

WATERFOWL

ISLAND

MICROPOOL

25’

WETLANDS

HIGH MARSH

100 YEAR LEVEL

10 YEAR LEVEL

Cpv OR 2 YEAR LEVEL

WQv LEVEL

INFLOW

FOREBAY

GABION WALL

LOW MARSH

POND DRAIN

REVERSE PIPE

BARREL

RISER

EMBANKMENT

EMERGENCY

SPILLWAY

STABLE

OUTFALL

ANTI-SEEP COLLAR or

FILTER DIAPHRAGM

PERMANENT

POOL

Figure 5.15: Schematic of a shallow wetland (MDE, 2000). 

addition to controlling runoff volumes and pollutant loadings. There are many variations of 

constructed wetlands, such as shallow wetlands, extended detention wetlands, pond/wetland 

systems, and small isolated “pocket” wetlands. Constructed wetlands may contain some or all of 

the following elements: shallow vegetated areas, permanent pools, sediment forebays, transition 

areas, and weirs. Designs are intended to slow flow through the wetlands and provide maximum 

contact with wetland vegetation. 

It should be noted, however, that constructed wetlands rarely replicate the functions of natural 

wetlands and should not be used for compensatory mitigation of natural wetlands and buffers. 

5-39 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Furthermore, constructed wetlands should be designed to receive periodic maintenance to ensure 

the wetland continues to function as designed. 

Constructed wetlands are feasible at most sites and drainage areas where there is enough rainfall 

and/or snowmelt to maintain a permanent pool. In areas with highly permeable soils, other 

impermeable barriers, such as synthetic liners or clay, sometimes can be used to maintain enough 

water or moisture to support the wetland. Constructed wetlands should be located contiguous to 

existing wetlands wherever possible, unless there is concern about contaminants that may pose a 

threat to wildlife. Although it is technically feasible to construct a wetland on a small site (less 

than 1 acre), alternative control strategies should be considered when land constraints are 

present. 

Constructed wetland systems can take several forms, including wet ponds with a wetland fringe, 

swale/ditch wetland depressions, and large-scale constructed wetlands used as mitigation 

wetlands or treatment wetlands. The choice of wetland designs depends on watershed 

characteristics, spatial and geomorphic constraints, runoff treatment requirements, and 

community and environmental factors. These considerations are outlined in Table 5.5. 

In the San Diego Creek Watershed in southern California, constructed wetlands are being used as 

a regional runoff control technique. This approach, called the Natural Treatment System (NTS) 

Plan, is part of a watershed-wide management effort to meet total maximum daily load (TMDL) 

requirements for the San Diego Creek, which is impaired by sediment, nutrients, pathogens, 

heavy metals, and pesticides. The results of water quality modeling that accounted for the 

combined effects of the 44 planned facilities indicated that the TMDL for total nitrogen in base 

flows would be achieved, total phosphorus targets would be met in all but the wettest years and 

the fecal coliform target would be met in the dry season. While the NTS Plan is not meant to 

meet the TMDL for sediment, it will capture 1,900 tons annually, and the wetlands are estimated 

to remove 18 percent of the total zinc and 11 percent of the total copper and lead in runoff 

(Strecker et al., 2003). 

New York City Bluebelt 

The New York City Department of Environmental Protection (NYCDEP) has taken an innovative 

approach to solving drainage problems that have long plagued southern Staten Island. Instead of 

installing a conventional piped storm sewer system that would destroy the existing wetlands through 

drainage or filling, NYCDEP proposed to use a natural drainage system to convey, store, and filter 

runoff. The plan involves both preserving and restoring wetlands. In 1991, the agency began 

purchasing land along wetland corridors, and soon this network of property was termed the Bluebelt, 

because it mirrors the role a Greenbelt plays for open space areas by protecting water resources. The 

Bluebelt area is a total of 10,000 acres and includes 16 watersheds. 

The constructed wetlands in the Bluebelt range from 0.5 to 2 acres in area and have a permanent pool 

that ranges from 12 to 24 inches deep. The wetlands are intended to provide water quality, flood 

control, and flow attenuation benefits for the region. More than 100 management practices were 

screened for their applicability, and in addition to constructed wetlands, meandering streams and outlet 

stilling basins were installed. Meandering streams convey runoff in open channels, providing a basis 

for the establishment and preservation of riparian areas. Outlet stilling basins mitigate the high 

velocities of runoff exiting conventional pipes. In the past 12 years, approximately half of the 89 

planned management practices have been designed (Vokral et al, 2003). 

5-40 
Management Measure 5: New Development Runoff Treatment 

Desert Wetlands 

A constructed wetland demonstration project is being tested in the Sonoran Desert to improve the 

New River, which consists primarily of wastewater from Mexico and agricultural drain water from 

California’s Imperial Valley (Fortner, 2000). Without these two sources of water, the New River would 

run dry. Near Imperial, California, about halfway along the New River, 68 acres of wetlands were 

constructed as a demonstration project. These wetlands use a series of six cells to remove sediments 

and other pollutants from irrigation drain water. A few miles downstream, in Brawley, California, a 

similar project will treat water that is diverted directly from the New River. The site for this project 

consists of 7 acres and three cells. The two sites are collectively referred to as the Brawley 

Constructed Wetlands Demonstration Project. 

The project is described as one of the most challenging constructed wetlands projects in the United 

States and will help researchers determine the best design for treating river and agricultural drain 

water. Scientists are aware that it will be challenging to construct a wetland to treat a severely 

impaired waterbody in a desert area. They will monitor the performance of the test sites before 

additional wetlands are built. Once the data is obtained, the Citizens’ Congressional Task Force for 

the New River (comprised of citizens and representatives from environmental groups, local community 

organizations, and state and federal agencies) will decide whether to expand the project. 

Wetlands and other runoff control systems should not be sited in areas where they disrupt or 

significantly alter the predevelopment hydrology unless restoration objectives apply. When 

designing the wetland, a variety of physical characteristics should be used to promote multiple 

wildlife and habitat functions. For example, an irregular shape increases the perimeter of the 

system and provides a greater variety of microhabitats along the shoreline. Also, an irregular 

shoreline can extend the perimeter of a constructed wetland by 10 to 20 percent with no increase 

in land requirements. 

Shallow-water wetlands do not contain a large volume of water per surface area as would a 

typical wet pond. In general, the wetland should have a shallow slope with a permanent pool in 

the middle. To enable growth of emergent vegetation, static water depths should not exceed 2 to 

3 feet. Depths greater than 2 to 3 feet are conducive to the growth of submerged aquatic 

vegetation. The use of deeper water (>3 feet) in an area that is easily accessible for small 

children should be discouraged. No area of the pond should have a depth greater than four feet. 

In general, 50 percent of the pond should have depths less than one foot, 30 percent should be 

1 foot to 2 feet deep, and 20 percent should be 2 to 4 feet deep. Greater depths are allowable for 

the inflow forebay and around the outlet structure. 

The Maryland Department of the Environment (2000) requires that the first inch of runoff from 

the site must be controlled and released over a 24-hour period to provide water quality treatment, 

while peak discharge control of the two- and 10-year storms must be provided for water quantity 

control. Local requirements should be used when designing the treatment capacity of a 

constructed wetland. Other factors such as steep slopes may necessitate deeper ponds to obtain 

adequate runoff control. 

Individual soil analyses should be done during the site design phase to determine if a clay or 

plastic liner is needed to maintain a wetland environment. Wetland vegetation cannot usually 

survive unless a base flow is available to provide a permanent pool to keep plants wet. Rapid 

infiltration will remove this needed pool. If a liner is needed, it should have at least 1 foot of 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

The Use of Wetlands to Reduce Fecal Coliform

Unusually high levels of fecal coliform have been found in an area of Laguna Niguel, California. Runoff 

from a neighborhood is washing into Aliso Creek and then to the Pacific Ocean. In response to a 

cleanup order issued by state water regulators, city officials built a series of wetlands to filter fecal 

coliform out of runoff. The natural water treatment system will work in combination with an existing 

wetland, which has already been proven successful in cleaning waters to a level acceptable for 

swimming. 

Upon completion, water will flow through a series of four stepped ponds, spread out, and remain in the 

wetlands for hours or days of treatment. It is estimated that it will take a year for all vegetation to grow 

in and nearly two years to attain maximum removal of bacteria. When the wetlands system is 

complete, the existing wetland will treat 35 to 40 percent of the runoff and the new wetlands will treat 

35 percent of the runoff. The city hopes that the new wetlands will work as well as the existing 

wetlands in reducing fecal coliform from urban runoff (Vardon, 2000). 

clean fill material placed on top of it for wetland plant growth (the fill material will also reduce 

the potential for puncture). 

An island placed in the wetland can extend the length of the flow path that runoff must travel to 

traverse the pond. This increased flow path enhances the pollution removal function of the 

constructed wetland. The highest elevation of the island should be above that reachable by 

storage of the first inch of runoff. Islands in wetlands may attract geese, which can be 

undesirable in some urban settings, but there are ways to minimize habitat for geese in a 

constructed wetland. Because most runoff management ponds are fairly small compared with a 

natural marsh system, they do not provide the long glide path preferred by geese for landing and 

takeoff. Planting woody vegetation or allowing areas around the pond to grow without mowing 

also tends to discourage goose residency. 

The following are typical elements of a constructed wetland: 

(1) Sediment forebays. It is important that sediment forebays be placed at all locations where 

runoff enters the wetland. A forebay is designed for vehicle access to facilitate sediment 

removal while preventing disturbance of substrate that could disrupt wetland functions. The 

forebay should constitute approximately 10 percent of the total basin volume and should 

have a maximum depth of 4 feet. Where there are multiple inlets to the constructed wetland, 

the total volume of all the forebays should be 10 percent of the basin volume, with individual 

inlet forebays sized with respect to the percentage of contributing flow they receive. The use 

of stone riprap in the forebay will reduce the velocity of flow into the wetland portion of the 

basin and minimize resuspension of deposited sediments. An access to the forebay should be 

provided for cleanout equipment. An area adjacent to the constructed wetland should be set 

aside for disposal of the sediments that become trapped and are removed during periodic 

maintenance. 

The cleanout frequency of sediment forebays depends on the sediment load entering the 

constructed wetland. Each forebay should be inspected annually to ensure cleanout is being 

conducted as needed. Once the forebay has been filled to approximately 50 percent of its 

total volume (every 10 to 15 years), sediment should be removed, placed in an appropriate 

upland location, and stabilized. Costs for sediment forebay maintenance, including periodic 

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Management Measure 5: New Development Runoff Treatment 

inspection and cleaning, should be budgeted as a long-term operating expense if this practice 

is selected. 

(2) Diversion weir. Diversion weirs may be needed for designs where the entire runoff volume is 

not directed to the constructed wetland. This diverted fraction of the runoff is often routed to 

collection systems or inlets. The amount of rainfall that may be diverted will vary according 

to local requirements and design objectives. 

(3) Outlet. As is the case with all ponds having a normal pool of water, algae can clog outlets 

with small orifices that are needed for extended detention. A below-surface withdrawal 

structure may reduce or eliminate this problem. 

(4) Transition zone. The maximum slope of the transition zone on wetland side slopes should be 

no greater than 10:1 (horizontal:vertical) and should extend at least 20 feet from the design 

pool of the constructed wetland. This area will be temporarily flooded whenever runoff is 

temporarily detained. Planting trees in the transition zone enhances nutrient uptake; the 

shading reduces temperature increases common in open water areas; and the trees provide 

habitat for wildlife. The transition zone should be mowed no more than once a year in late 

fall. Optimally, to promote the growth of woody vegetation, the transition area should not be 

mowed at all unless the pond is an embankment pond, in which case it should be mowed 

annually to prevent woody vegetation on the embankment. 

(5) Vegetation. Placement of organic soils on the bottom of the pond will provide faster growth 

of planted or volunteer vegetation. Constructed wetlands should initially be planted with 

emergent plants and woody shrubs, and the wetlands should be allowed to succeed to a 

system dominated by woody shrubs and trees. The emergent wetland plants that are chosen 

should have tops that rise above the normal pool level. 

It is important to consult local ecologists/plant specialists to choose suitable wetland species 

and to design a landscaping plan with appropriate vegetation density and spacing. Local 

specialists can also provide information regarding the optimal time to plant vegetation and 

help to design a maintenance schedule based on vegetation requirements. Native species 

should be used where feasible because they are well-adapted to local conditions. The USDA 

has a database (see http://www.plants.usda.gov/) of invasive and noxious species, which 

should be avoided. 

The following specifications are provided as an example and apply to the Mid-Atlantic 

region (MDE, 2000): 

— At least two aggressive species should be planted in the constructed wetland; their 

purpose is to rapidly spread to other unplanted areas of the wetland. In addition, at 

least three secondary species should be planted to increase the diversity, wildlife 

values, and appearance of the wetland. Ideally, plantings should include a mix of 

perennial and annual species. 

— Plants should cover approximately 30 percent of shallow areas, with particular 

attention paid to areas adjacent to the shoreline. Plants should be spaced 2 to 3 feet 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

apart, and the same species of plants should be planted in a single area to avoid 

interspecies competition. 

— Species that are not recommended for any use in a constructed wetland are 

Phragmites australis (common reed), Lythrum salicaria (purple loosestrife), and 

Phalaris arundinacea (reed canary grass). Periodic inspections are important to 

ensure that exotic or other pest species do not dominate the plant community. In 

certain situations where there is an initial invasion of an aggressive, undesirable 

species, selective removal of the plants might be warranted, especially if the plant 

community that was introduced has not had time to adequately establish itself. 

— Depending on site conditions, planting Typha latifolia (cattail) may or may not be 

recommended. Despite the fact that it is considered an exotic species, cattail will 

eventually dominate the wetland community. Additionally, cattail is an excellent 

plant for water treatment from a filtration and sedimentation standpoint. 

— Planting will be more successful if the water level can be drawn down immediately 

prior to planting. This drawdown will leave the soils saturated, a condition necessary 

for the plants, and will improve visibility, especially when a number of people are 

involved in planting. The potential for damaging previously planted vegetation is 

reduced if the plants are clearly visible. Upon completion of planting, the outlet 

structure drain valve should be closed so either storm or base flow can reestablish the 

normal pool elevation. 

— Harvesting wetland plants is only appropriate in areas such as the southern United 

States where plant growth is the most important mechanism for nutrient uptake. 

Harvesting is not needed where microbial activity is the dominant pollutant removal 

mechanism. 

Like wet ponds, wetlands can increase adjacent property values. One study in Boulder, Colorado, 

found that lots located alongside a constructed wetland sold for up to a 30 percent premium over 

lots with no water view (USEPA, 1995). In Wichita, Kansas, a developer enhanced existing 

wetlands rather than filling them, and the waterfront lots sell for a premium of up to 150 percent 

of comparable lots (USEPA, 1995). 

5.3.5 Other Practices 

Other practices used to control urban runoff have not been studied as extensively as those above 

but have been used with varying degrees of success. They include: 

— Water quality inlets; 

— Hydrodynamic devices; 

— “Baffle boxes;” 

— Catch basin inserts; 

— Vegetated filter strips; 

— Street surface storage; 

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Management Measure 5: New Development Runoff Treatment 

— On-lot storage; and 

— Microbial disinfection. 

In some cases, these practices are used for pretreatment or are part of an overall runoff 

management system, which is sometimes referred to as a “treatment train.” For example, water 

quality inlets, catch basin inserts, and vegetated filter strips installed upslope of a wet pond or 

filtration practice will help remove a portion of the pollutants present in runoff before it enters 

the pond or filtration practice. These other practices in the treatment train improve runoff quality 

and can help extend the longevity of the filtration practice and wet pond. 

5.3.5.1 Water quality inlets 

Water quality inlets are underground retention systems designed to remove settleable solids. 

There are several water quality inlet designs. In their simplest form, catch basins are singlechambered urban runoff inlets in which the bottom has been lowered to provide 2 to 4 feet of 

additional space between the outlet pipe and the structure bottom for collection of sediment. 

Some water quality inlets include a second chamber with a sand filter to provide additional 

removal of finer suspended solids by filtration. The first chamber provides effective removal of 

coarse particles and helps prevent premature clogging of the filter medium. 

Other water quality inlets include an oil/grit separator. Typical oil/grit separators consist of three 

chambers. The first chamber removes coarse material and debris; the second chamber provides 

separation of oil, grease, and gasoline; and the third chamber provides safety relief if blockage 

occurs (NVPDC, 1980). Although water quality inlets have the potential to perform effectively, 

they are not recommended because they are usually designed to bypass high flows, which can 

resuspend captured pollutants and flush them through the water quality inlet. Frequent 

maintenance and disposal of trapped residuals and hydrocarbons are necessary for these devices 

to continuously and effectively remove pollutants. 

5.3.5.2 Hydrodynamic devices 

A variety of engineered hydrodynamic devices, also called swirl separators or swirl 

concentrators, are available for removing pollutants from runoff. Swirl separators are 

modifications of the traditional oil-grit separator and include an internal component that creates a 

swirling motion as runoff flows through a cylindrical chamber. The concept behind these designs 

is that sediments settle out as runoff moves in this swirling path. Additional compartments or 

chambers, with or without pads, are sometimes present to trap oil and other floatables. Typically 

these devices are prefabricated and come in a range of sizes targeted at specific flow rates. At 

least two technologies are available. One is designed to remove suspended particles, oil, and 

grease during low flow conditions. The device removes particulate and floatable pollutants from 

runoff through settling of solids and floating of oils, greases, and litter. Higher runoff flows are 

diverted around the treatment unit so that scour and increased velocity do not carry the collected 

pollutants out of the treatment chamber. Maintenance requirements include the periodic removal 

of oil, greases, and sediments, typically by using a vacuum truck. 

A second type of hydrodynamic device uses centrifugal motion to remove litter and debris and, 

potentially, larger sediment particles from runoff. This technology is designed to capture trash 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

rather than pollutants, and therefore it is most applicable in coastal areas and areas that receive 

heavy trash loads such as leaf litter, plastics, and cans. Prefabricated units are currently available 

with capacities up to 300 cubic feet per second (cfs). The devices are constructed so that a 

vacuum truck can regularly remove the floatable and settleable debris collected in the treatment 

chamber. 

Limited data are available on the performance of these devices, and independently conducted 

studies suggest marginal fine particle and soluble pollutant removal. Therefore, swirl separators 

should not be used as a stand-alone practice for new development. Also, these devices require 

regular maintenance. Communities may reduce maintenance costs by sharing a vactor truck. 

Swirl separators are best installed on highly impervious sites. These products have application as 

pretreatment to another runoff treatment practice and in a retrofit situation where space is 

limited. 

5.3.5.3 Baffle boxes 

Sediment control devices called “baffle boxes” have been used in Brevard County, Florida, as an 

“end of pipe” treatment method (England, 1996). They are concrete or fiberglass boxes, typically 

10 to 15 feet long and 6 to 8 feet high, which are placed at the end of existing storm drain pipes. 

The box is divided into multiple chambers by weirs set at the same level as the pipe invert to 

minimize hydraulic losses. Trash screens are incorporated in the design to remove floating 

debris. Baffle boxes have been shown to have a removal efficiency of up to 90 percent for sand 

or sandy clay at entrance velocities of up to 6 feet per second, and 28 percent removal efficiency 

for fly ash at the same velocity. Baffle box designs can be modified to serve as a retrofit 

installation at curb or manhole inlets or beneath grates. Regular maintenance, especially removal 

of sediment and debris, is essential to maintain the effectiveness of this practice. 

5.3.5.4 Catch basin inserts 

Catch basin inserts consist of a frame that fits below the inlet grate of a catch basin and can be 

fitted with various trays that target specific pollutants. Typically the frame and trays are made of 

stainless steel, cast iron, or aluminum to resist corrosion. The trays may contain a variety of 

media. Often more than one tray is included in the design with the first tray filtering out 

sediment. Subsequent trays typically address a specific targeted pollutant, (e.g., wood fiber or 

other absorbent materials for oils and grease, or activated carbon for organics, fertilizers, and 

pesticides). The device is typically designed to accept the design flow rate of the inlet grate with 

bypasses as the trays become clogged with debris. The media require routine maintenance for 

replacement, cleaning, or regeneration. Catch basin inserts are typically used for smaller 

drainage areas. Usually the media need replacement on a quarterly basis. 

The City of Santa Monica installs catch basin inserts that catch trash and debris in areas of high 

pedestrian traffic. Catch basin screens attach to the face of the curb and block trash from the 

storm drain, allowing debris to be easily removed by maintenance personnel or a street sweeper. 

Inserts that also filter hydrocarbons are installed on streets with automotive businesses. The city 

has found these practices to be effective when they are chosen carefully to suit site 

characteristics and are carefully installed and maintained (Shapiro, 2003). 

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Management Measure 5: New Development Runoff Treatment 

5.3.5.5 Alum 

Alum, which is an aluminum sulfate salt, can be added to storm water to cause fine particles to 

flocculate and settle out (USEPA, 2001a). It can help meet downstream pollutant concentration 

loads by reducing the concentrations of fine particles and soluble phosphorus. Alum can be 

added directly to or just before a pond or lake inlet, and booms can be used to ensure quiescent 

settling. When alum is injected into runoff it forms the harmless precipitates aluminum 

phosphate and aluminum hydroxide. These precipitates combine with heavy metals and 

phosphorus, causing them to be deposited into the sediments in a stable, inactive state. The 

collected mass of alum pollutants, precipitates, and sediments is commonly referred to as “floc.” 

Frequent maintenance and disposal of the floc is required for continuous and effective operation. 

5.3.5.6 Vegetated filter strips 

Vegetated filter strips (VFSs) (Figure 5.16) are areas of land with vegetative cover that are 

designed to accept runoff as overland sheet flow from upstream development. Dense vegetative 

cover facilitates sediment attenuation and pollutant removal. Unlike grassed swales, vegetated 

filter strips are effective only for overland sheet flow and provide little treatment for 

concentrated flows. Grading and level spreaders can be used to create a uniformly sloping area 

that distributes the runoff evenly across the filter strip (Dillaha et al., 1989). Vegetated filter 

strips are often used as pretreatment for other structural practices, such as infiltration basins and 

infiltration trenches. 

Typically, VFSs are used to treat very small drainage areas. The limiting design factor, however, 

is not the drainage area the practice treats but the length of flow leading to it. As runoff flows 

over the ground surface, it changes from sheet flow to concentrated flow. Rather than moving 

uniformly over the surface, the concentrated flow forms rivulets that are slightly deeper and 

cover less area than the sheet flow. When flow concentrates, it moves too rapidly to be 

effectively treated by a grassed filter strip. 

VFSs should be designed on slopes between 2 and 6 percent. Steeper slopes encourage the 

formation of concentrated flow. Except in the case of very sandy or gravelly soil, runoff ponds 

on the surface on slopes flatter than 2 percent, creating potential mosquito-breeding habitat. 

Filter strips should not be used on soils with high clay content because they require infiltration 

for proper treatment. Very poor soils that cannot sustain a grass cover crop are also a limiting 

factor. Filter strips should be separated from the ground water by 2 to 4 feet to prevent 

contamination and to ensure that they do not remain wet between storms. 

The design of VFSs is straightforward because they are not much more than a grassed slope. 

However, the following design features are critical to ensure that the filter strip provides some 

minimum amount of water quality treatment: 

— A pea gravel diaphragm or stone drop should be used at the top of the slope. The pea 

gravel diaphragm (a small trench running along the top of the filter strip) serves two 

purposes. First, it acts as a pretreatment device, settling out sediment particles before they 

reach the practice. Second, it acts as a level spreader, maintaining sheet flow as runoff 

flows over the filter strip. 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Figure 5.16: Schematic of a vegetated filter strip (Claytor and Schueler, 1996). 

— The filter strip should be designed with a pervious berm of sand and gravel at the toe of 

the slope. This feature provides an area for shallow ponding at the bottom of the filter 

strip. Runoff ponds behind the berm and gradually flows through outlet pipes in the berm. 

The volume ponded behind the berm should be equal to the water quality volume. The 

water quality volume is the amount of runoff that will be treated for pollutant removal in 

the practice. Typical water quality volumes are the runoff from a 1-inch storm or 1⁄2-inch 

of runoff over the entire drainage area to the practice. 

— The filter strip should have a length of at least 25 feet to provide water quality treatment. 

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Management Measure 5: New Development Runoff Treatment 

— Vegetation must be able to withstand relatively high velocity flows and both wet and dry 

periods. 

— The slope should have a flat top and toe to encourage sheet flow and prevent erosion. 

5.3.5.7 Street surface and subsurface storage 

Runoff can be temporarily stored on and 

below the surface of streets in urban areas, 

as shown in Figure 5.17, to reduce peak 

flows to the storm sewer system (Carr et 

al., 1999). Runoff can be retained on and 

below the street using a combination of 

berms, flow regulators, and below-surface 

storage. Berms resemble speed bumps or 

speed humps but are broader and gentler; 

they retain water in a shallow pool on the 

street surface upstream of the berm. In 

some cases, this type of surface storage is 

inappropriate because it can result in 

damage to roadways. An alternative is 

subsurface storage in tanks or large sewer 

pipes. Both above- and below-ground 

storage systems, when combined with flow 

regulators that allow only a limited amount 

of runoff to enter the sewer system, 

mitigate basement flooding, combined sewer overflows, sanitary sewer overflows, and surface 

flooding. These systems should be designed with public safety in mind to minimize hydroplaning 

and icing in cold climates. 

Figure 5.17: Runoff pooling on a street 

surface designed for temporary storage. 

Two suburban Chicago, Illinois, towns—Skokie and Wilmette—implemented street-surface 

storage of runoff. The Skokie system has 2,900 flow regulators, 871 berms, 10 off-street storage 

facilities, 83 subsurface facilities, and several new storm and combined sewers (USEPA, 2000b). 

Wilmette’s runoff storage system is composed of essentially all street storage. These systems 

have been effective in preventing flooding and overflows and are less expensive than other 

alternatives such as sewer separation and relief sewers. More information about these studies can 

be found at http://www.epa.gov/ednnrmrl/publications/reports/epa600r00065/epa600r00065.htm. 

5.3.5.8 On-lot storage practices 

The term “on-lot storage” refers to a series of practices that are designed to contain runoff from 

individual lots. The purpose of most on-lot practices is to manage rooftop or parking area runoff. 

The primary advantage of managing runoff from rooftops and parking lots is to disconnect these 

impervious surfaces, reducing the effective impervious cover in a watershed. 

Johnston et al. (2003) modeled the downstream hydrologic and economic impacts of on-site 

runoff storage based on flood risk reduction on property values and costs of storm drainage 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

infrastructure. They found that use of reduced runoff practices provided property value benefits 

due to decreased flood risk of $21,600 to $36,300 per acre using countywide assessed values, or 

$17,540 to $29,240 per acre using U.S. Census Bureau census block median housing values. 

Benefits in avoided costs for storm drainage infrastructure (road culverts) totaled $247 to $836 

per developed acre. 

Although there are many on-lot treatment options, they can all be classified into one of three 

categories: (1) practices that infiltrate runoff; (2) practices that divert runoff to a pervious area; 

and (3) practices that store runoff for later use. The best option depends on the goals of a 

community, the feasibility at a specific site, and the preferences of the property owner. 

Rooftop Runoff 

Rooftop runoff, particularly in residential areas, generally has low pollutant concentrations 

compared with other urban sources (Schueler, 1994). Information on green rooftops can be found 

in Section 4.3.2.2. The practice most often used to infiltrate rooftop runoff is the dry well. In this 

design, the storm drain is directed to an underground rock-filled trench that is similar in design to 

an infiltration trench. French drains or Dutch drains can also be used for this purpose. In these 

designs, the relatively deep dry well is replaced with a long trench with a perforated pipe within 

the gravel bed to distribute flow throughout the length of the trench. Chamber systems, a widely 

marketed proprietary product, can be used in a similar manner. 

Runoff can be diverted to a pervious area or to a treatment area using site grading or channels 

and berms. Treatment options can include grassed swales, bioretention cells, or filter strips. The 

bioretention design can be simplified for an on-lot application by limiting the pretreatment filter 

and in some cases eliminating the underdrain. Alternatively, rooftop runoff can simply be 

diverted to pervious lawn areas instead of discharging it directly to the street or a pipe drainage 

system. 

Figure 5.18: A rain barrel that collects 

runoff from a roof gutter downspout. 

Practices that store rooftop runoff, such as 

cisterns, chambers, and rain barrels (Figure 5.18), 

are the simplest designs for on-lot treatment 

systems. Some of these practices are available 

commercially and can be applied in a variety of 

site conditions. Cisterns and rain barrels are 

particularly valuable in the arid Southwest, where 

water is at a premium, rainfall is infrequent, and 

reuse for irrigation can save homeowners money. 

Rain barrels typically range in cost from $60 to 

$135. These prices do not always include the cost 

of additional parts needed to link the rain barrel 

to a downspout. These parts generally range in 

cost from $5 to $18, depending on the 

manufacturer and the design of the rain barrel 

(Gardener’s, 2001; Jade Mountain, 2000; 

Midwest, 2001; Spruce Creek, 2001). If 

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Management Measure 5: New Development Runoff Treatment 

homeowners want to save money, they can build their own rain barrel, which costs 

approximately $15 if recycled drums are available. 

Information about building a simple rain barrel is available from the Maryland Green Building 

Program at http://www.dnr.state.md.us/ed/rainbarrel.html (MDNR, no date). Information is also 

available in How to Make a Rain Barrel, which was published by the city of Ottawa, Ontario (no 

date). The manual is available by contacting the city of Ottawa toll-free at 866-261-9799, or by 

e-mailing info@city.ottawa.on.ca. 

It is important for municipalities planning to start a rain barrel program to consider water quality 

issues, climate, algae and mosquito control, homeowner attitudes and willingness, and the 

protection of home foundations. Rain barrels can be a reliable source of water for garden and 

lawn watering, but if the water is intended for consumption it is crucial that the roof materials 

and gutter system be examined for asbestos, lead paint, and bird droppings (Sands and Chapman, 

2003). 

The Milwaukee Metropolitan Sewerage District (MMSD) undertook a rain barrel project in 

response to problems with combined sewer overflows. The project involved 40,000 single-family 

homes with roof areas of approximately 1,200 square feet. Two 90-gallon rain barrels were 

installed at each home. The MMSD found the reduction in runoff volume attributed to rain 

barrels to be approximately 243 million gallons. While the effort did not reduce combined sewer 

overflow volumes for the MMSD, it did result in savings on treatment plant costs and increased 

environmental awareness. The MMSD plans to continue to incorporate rain barrels into an 

integrated management plan that might include additional on-lot treatment practices (Sands and 

Chapman, 2003). 

On-lot treatment practices can be applied to almost all sites with very few exceptions (e.g., very 

small lots or lots with no landscaping). There are currently at least two jurisdictions that offer 

“credits” in exchange for the application of on-site runoff management practices. In Denver, 

Colorado, sites designed with methods to reduce “directly connected impervious cover,” 

including disconnection of downspout runoff from the storm drain system, are permitted to use a 

lower impervious area when computing the required storage of runoff management facilities 

(DUDFC, 1992). Similarly, new regulations for Maryland allow designers to subtract each 

rooftop that is disconnected from the total site impervious cover when calculating required 

storage in runoff management practices (MDE, 2000). 

Although most residential lots can incorporate on-lot treatment, the best option for a site depends 

on design constraints and the preferences of the homeowner. On-lot infiltration practices have 

the same restrictions regarding soils as other infiltration practices. If other design practices are 

used, such as bioretention or grassed swales, they need to meet the siting requirements of those 

sites. Of all of the practices, cisterns and rain barrels have the fewest site constraints. In order for 

the practice to be effective, however, homeowners need to have a use for the water stored in the 

practice, and the design must accommodate overflow and winter freezing conditions. 

Although these runoff management practices are simple compared with many others, their design 

needs to incorporate the same basic elements. Pretreatment is important for all of these practices 

to ensure that they do not become clogged with leaves or other debris. Infiltration practices may 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Santa Monica’s comprehensive urban runoff program combines pollution prevention and on-site 

practices with a runoff recycling program designed to improve water quality and harvest dry weather 

runoff as a resource. By protecting existing water resources, increasing infiltration on-site, and 

harvesting runoff for reuse, the city is maximizing the use of storm water as a resource and 

decreasing the demand for imported water. The city’s pollution prevention program protects water 

quality with education, municipal housekeeping, lawn care and landscaping practices, and an 

ordinance that requires good housekeeping practices on construction sites. On-site practices are 

required by the Urban Runoff Pollution Mitigation Ordinance and include infiltration practices, porous 

pavement, and other low impact development techniques. The city has also installed catch basin 

inserts and screens to capture trash, debris, and some soluble pollutants. Finally, the Santa Monica 

Urban Runoff Recycling Facility (SMURRF) harvests and treats dry weather runoff and makes it 

available for reuse as irrigation water or for indoor toilet flushing (Shapiro, 2003). 

Santa Monica Urban Runoff Program

be preceded with a settling tank or, at a minimum, a grate or filter in the downspout to trap 

leaves and other debris. Rain barrels and cisterns also often incorporate some sort of 

pretreatment, such as a mesh filter at the top of the barrel or cistern. 

Both infiltration practices and storage practices should incorporate some type of bypass so runoff 

from larger storms flows away from the house. With rain barrels or cisterns, this bypass may be a 

hose set at a high level within the device that directs runoff away from both the device and the 

building foundation. These practices also include a hose bib set at the bottom of the device so the 

homeowner can use the stored water for irrigation or other uses by attaching a standard garden 

hose to the hose bib. 

One important design requirement for on-lot infiltration practices is locating the infiltration area 

sufficiently far from the house (at least 10 feet) to prevent undermining of the foundation or 

seepage into the basement. 

Infiltration practices require regular removal of sediment and debris settled in the pretreatment 

area, and the infiltration medium needs to be replaced when it becomes clogged. Rain barrels and 

cisterns require minimal maintenance, but the homeowner must ensure that the hose remains 

elevated during the winter to prevent freezing and cracking. In addition, the tank requires 

cleaning approximately once a year. 

On the basis of cost per unit area treated, on-lot practices are relatively expensive compared with 

other runoff storage and treatment options. It is difficult to make this comparison, however, 

because the cost burden of on-lot practices is borne directly by homeowners. Typical costs are 

$100 for a rain barrel and $200 for a dry well or French drain. Often, homeowners can reduce 

costs by creating their own on-lot practice rather than purchasing a commercial product. 

Parking Lot Runoff 

Standard parking lots typically drain rapidly through curb and gutter systems to prevent flooding. 

This practice, however, does little to improve water quality or protect receiving waters from high 

flows during and after storms. Innovative designs for parking lots incorporate pervious areas for 

drainage, whether at the perimeter or in various islands within the lot. These pervious areas 

5-52 
Management Measure 5: New Development Runoff Treatment 

should be designed to infiltrate runoff at rates that prevent excessive ponding, which could 

appear unsightly or create safety issues and nuisance mosquito habitat. In cases where existing 

soils have poor infiltration capacity, better-drained soils should be imported or perforated underdrains installed to store infiltrated runoff underground. 

The use of large-diameter underground pipes constructed of concrete, corrugated steel, or highdensity polyethylene (HDPE) is becoming a more common practice for large parking areas such 

as shopping malls and mixed-use developments. These underground pipes and vaults as well as 

chamber systems can store large quantities of runoff that can be reused as needed or released at 

rates that will not damage natural conveyance systems. 

5.3.5.9 Microbial disinfection 

Other practices can be used to treat runoff for specific pollutants other than sediment. For 

instance, in areas where microbial pollution is an issue, runoff can be treated using ozone or 

ultraviolet light to prevent disease and reduce exceedances of water quality due to pathogen 

contamination. The City of Encinitas, California, was concerned about the number of public 

health warnings at its primary seaside attraction, Moonlight Beach, due to high enterococcus and 

coliform bacteria counts. The main source of the microbial pollution was dry weather runoff 

from Cottonwood Creek, which discharges at Moonlight Beach. Despite extensive evaluation of 

the Cottonwood Creek drainage area to identify and reduce bacterial loading, public health 

warnings continued to be posted. In anticipation of a total maximum daily load for bacteria under 

development for the region, and to reduce or eliminate the number of beach postings, the City 

chose to install an ultraviolet (UV) disinfection facility with partial funding from California’s 

Clean Beach Initiative. The UV treatment facility was designed to treat 150 gallons per minute of 

Cottonwood Creek’s dry weather flow, with 15% of the creek’s flow diverted around the facility 

to maintain biological connectivity between upstream and downstream waters. During times of 

high flow (i.e., during and after storms) and high turbidity, when the system’s treatment 

effectiveness would be reduced, the system is shut down and flow is passed through without 

treatment. Early monitoring results showed a significant decrease in bacterial counts downstream 

of the treatment facility, with a removal efficiency of more than 99.9 percent that yielded an 

effluent quality of 2 bacteria per 100 mL. Filters built into the system were also effective at 

removing suspended sediment, reducing turbidity from an average of 14.0 mg/L in the influent to 

5.0 mg/L in the effluent. 

5-53 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

5.4 Performance and Cost Information for Management Practices 

Some advantages, disadvantages, and costs of specific runoff control practices described above 

are listed in Table 5.6. Site-specific information, regional limitations, operation and maintenance 

burdens, and longevity for these practices are listed in Table 5.7. 

Table 5.6: Advantages and disadvantages of management practices (MDE, 2000). 

Practice Advantages Disadvantages 

Comparative 

Costa

 Runoff control ponds 

Wet pond — Can provide peak flow control 

— Can serve large developments; 

most cost-effective for larger, 

more intensively developed sites 

— Enhances aesthetics and provides 

recreational benefits 

— Little ground water discharge 

— Permanent pool in wet ponds 

helps to prevent scour and resuspension of sediments 

— Provides moderate to high 

removal of both particulate and 

soluble urban runoff pollutants 

— Not economical for drainage area 

less than 10 acres 

— Potential safety hazards if not 

properly maintained 

— If not adequately maintained, can 

be an eyesore, breed mosquitoes, 

and create undesirable odors 

— Requires considerable space, 

which limits use in densely 

urbanized areas with expensive 

land and high property values 

— Not suitable for hydrologic soil 

groups “A” and “B” (USDANRCS classification) unless a 

liner is used 

— With possible thermal discharge 

and oxygen depletion, may 

severely impact downstream 

aquatic life 

— Hydrologic damage to stream 

channels and aquatic habitat is 

possible due to flow volume. 

Moderate to high 

compared to 

conventional 

runoff detention 

Infiltration practices 

Infiltration 

basin 

— Provides ground water recharge 

— Can serve large developments 

— High removal capability for 

particulate pollutants and 

moderate removal for soluble 

pollutants 

— When basin works, it can replicate 

predevelopment hydrology more 

closely than other BMP options 

— Basins provide more habitat value 

than other infiltration systems 

— Possible risk of contaminating 

ground water 

— Only feasible where soil is 

permeable and there is sufficient 

depth to bedrock and water table 

— Fairly high failure rate 

— If not adequately maintained, can 

be an eyesore, breed mosquitoes, 

and create undesirable odors 

— Regular maintenance activities 

cannot prevent rapid clogging of 

infiltration basin 

Construction 

cost moderate 

but rehabilitation 

cost high 

5-54 
Management Measure 5: New Development Runoff Treatment 

Table 5.6 (continued). 

Practice Advantages Disadvantages 

Comparative 

Costa

Infiltration 

trench 

— Provides ground water recharge 

— Can serve small drainage areas 

— Can fit into medians, perimeters, 

and other unused areas of a 

development site 

— Helps replicate predevelopment 

hydrology, increases dry weather 

baseflow, and reduces bankfull 

flooding frequency 

— Possible risk of contaminating 

ground water 

— Only feasible where soil is 

permeable and there is sufficient 

depth to bedrock and water table 

— Since not as visible as other 

BMPs, less likely to be 

maintained by residents 

— Requires significant maintenance 

— Cost-effective 

on smaller 

sites 

— Rehabilitation 

costs can be 

considerable 

Concrete 

grid 

pavement 

— Can provide peak flow control 

— Provides ground water recharge 

— Provides water quality control 

without additional consumption of 

land 

— Requires regular maintenance 

— Not suitable for areas with high 

traffic volume 

— Possible risk of contaminating 

ground water 

— Only feasible where soil is 

permeable, there is sufficient 

depth to bedrock and water table, 

and there are gentle slopes 

Information not 

available 

Filtering practices 

Filtration 

basin 

— Ability to accommodate mediumsize development (3–80 acres) 

— Flexibility to provide or not 

provide ground water recharge 

— Can provide peak volume control 

— Requires pretreatment of runoff 

through sedimentation to prevent 

filter media from premature 

clogging 

Information not 

available 

Bioretention — Provides ground water recharge —

Open channel practices 

Grassed 

swale 

— Requires minimal land area 

— Can be used as part of the runoff 

conveyance system to provide 

pretreatment 

— Can provide sufficient runoff 

control to replace curb and gutter 

in single-family residential 

subdivisions and on highway 

medians 

— Economical 

— Low pollutant removal rates 

— Leaching from culverts and 

fertilized lawns may actually 

increase the presence of trace 

metals and nutrients 

Low compared 

to curb and 

gutter 

Structural management practices that do not consistently remove 80% TSS 

Vegetated 

filter strip 

— Low maintenance requirements 

— Can be used as part of the runoff 

conveyance system to provide 

pretreatment 

— Can effectively reduce particulate 

pollutant levels in areas where 

runoff velocity is low to moderate 

— Provides excellent urban wildlife 

habitat 

— Economical 

— Often concentrates water, which 

significantly reduces effectiveness 

— Ability to remove soluble 

pollutants highly variable 

— Limited feasibility in highly 

urbanized areas where runoff 

velocities are high and flow is 

concentrated 

— Requires periodic repair, 

regrading, and sediment removal 

to prevent channelization 

Low 

5-55 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Table 5.6 (continued). 

Practice Advantages Disadvantages 

Comparative 

Costa

Water 

quality inlet 

Catch basins 

with sand 

filter 

— Provide high removal efficiencies 

of particulates 

— Require minimal land area 

— Flexibility to retrofit existing 

small drainage areas 

— Higher removal of nutrient as 

compared to catch basins and 

oil/grit separator 

— Not feasible for drainage areas 

greater than 5 acres 

— Only feasible for areas that are 

stabilized and highly impervious 

— Not effective as water quality 

control for intense storms 

Information not 

available 

Water 

quality inlet 

Oil/grit 

separator 

— Captures coarse-grained 

sediments and some hydrocarbons 

— Requires minimal land area 

— Flexibility to retrofit existing 

small drainage areas and 

applicable to most urban areas 

— Shows some capacity to trap 

trash, debris, and other floatables 

— Can be adapted to all regions of 

the country 

— Not feasible for drainage area 

greater than 1 acre 

— Minimal nutrient and organic 

matter removal 

— Not effective as water quality 

control for intense storms 

— Concern exists for the pollutant 

toxicity of trapped residuals 

— Require high maintenance 

High, compared 

to trenches and 

sand filters 

Extended 

detention 

dry pond 

with 

micropool 

— Can provide peak flow control 

— Possible to provide good 

particulate removal 

— Can serve large development 

— Requires less capital cost and land 

area when compared to wet pond 

— Does not generally release water 

or anoxic water downstream 

— Provides excellent protection for 

downstream channel erosion 

— Can create valuable wetland and 

meadow habitat when properly 

landscaped 

— Removal rates for soluble 

pollutants are quite low 

— Not economical for drainage area 

less than 10 acres 

— If not adequately maintained, can 

be an eyesore, breed mosquitoes, 

and create undesirable odors 

Lowest cost 

alternative in 

size range

a

Comparative cost information from Schueler, 1992 

5-56 
Management Measure 5: New Development Runoff Treatment 

Table 5.7: Regional, site-specific, and maintenance considerations for management 

practices (USEPA, 1993; Caraco and Claytor, 1997; Schueler, in press). 

Management Practice and Specifications

Cold Climate Restrictions 

(Caraco and Claytor, 1997) 

Arid and Semi-Arid 

Regional Restrictions 

(Schueler, in press) 

Infiltration basins 

Size of drainage area: Moderate to large 

Site requirements: Deep, permeable soils 

Maintenance burdens: High 

Longevity: Low 

— Avoid areas with permafrost 

— Monitor ground water for chlorides 

— Do not infiltrate road/parking lot 

snowmelt if chlorides are a concern 

— Increase percolation requirements 

— Use 20 foot minimum setback between 

road subgrade and practice 

— No recharge in hotspot areas 

— Do not treat pervious 

areas 

— Use multiple 

pretreatment 

— Soil limitations exist 

in arid areas 

Infiltration trenches 

Size of drainage area: Moderate 

Site requirements: Deep, permeable soils 

Maintenance burdens: High 

Longevity: Low 

— Avoid areas with permafrost 

— Monitor ground water for chlorides 

— Do not infiltrate road/parking lot 

snowmelt if chlorides are a concern 

— Increase percolation requirements 

— Use 20-foot minimum setback between 

road subgrade and practice 

— No recharge in hotspot areas 

— Do not treat pervious 

areas 

— Use multiple 

pretreatment 

— Soil limitations exist 

in arid areas 

Vegetated filter strips 

Size of drainage area: Small 

Site requirements: Low-density areas with 

low slopes 

Maintenance burdens: Low 

Longevity: Low if poorly maintained 

— Small setback may be required between 

filter strips and roads when frost heave 

is a concern 

— Avoid areas with permafrost 

— Use cold- and salt-tolerant vegetation 

— Plowed snow can be stored in-practice 

— Use drought-tolerant 

vegetation 

Grassed swales 

Size of drainage area: Small 

Site requirements: Low-density areas with 

<15% slope 

Maintenance burdens: Low 

Longevity: High if maintained 

— Avoid areas with permafrost 

— Use cold- and salt-tolerant vegetation 

— Plowed snow can be stored in the 

practice 

— Increase underdrain pipe diameter and 

size of gravel bed 

— Provide ice-free culverts 

— Ensure soil bed is highly permeable 

— Not recommended 

for pollutant removal 

in arid areas 

— Of limited use in 

semi-arid areas 

— Ensure adequate 

erosion protection of 

channels 

Porous pavement 

Size of drainage area: Small 

Site requirements: Deep permeable soils, 

low slopes, and restricted traffic 

Maintenance burdens: Moderate to high 

Longevity: Low 

— Only use on non-sanded surfaces 

— Pavement may be damaged by snow 

plows 

— Maintenance is essential 

Filtration basins and sand filters 

Size of drainage area: Widely applicable 

Site requirements: Widely applicable 

Maintenance burdens: Moderate 

Longevity: Low to moderate 

— Reduced treatment effectiveness during 

cold season 

— Underground filters only effective if 

placed below the frost line 

— Peat/compost media ineffective during 

winter and may become impervious if 

frozen 

— Preferred in both arid 

and semi-arid areas. 

Arid area filters 

require greater 

pretreatment 

Bioretention — Reduced treatment effectiveness during 

cold season 

— Pretreatment should be used to prevent 

“choking” of vegetation 

5-57 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Table 5.7 (continued). 

Management Practice and Specifications

Cold Climate Restrictions 

(Caraco and Claytor, 1997) 

Arid and Semi-Arid 

Regional Restrictions 

(Schueler, in press) 

Water quality inlets 

Size of drainage area: Small 

Site requirements: Impervious catchments 

Maintenance burdens: Cleaned twice a 

year 

Longevity: High 

— Few restrictions 

Extended detention dry ponds 

Size of drainage area: Moderate to large 

Site requirements: Deep soils 

Maintenance burdens: Dry ponds have 

relatively high burdens 

Longevity: High 

— Protect inlet/outlet pipes 

— Use large-diameter (> 8 in) gravel in 

underdrain of outfall protection 

— Consider seasonal operation 

— Provide ice storage volume 

— Cold-tolerant vegetation 

— Preferred in arid 

climates and 

acceptable in semiarid climates 

Wet ponds 

Size of drainage area: Moderate to large 

Site requirements: Deep soils 

Maintenance burdens: Low 

Longevity: High 

— Protect inlet/outlet pipes 

— Use large-diameter (> 8 in) gravel in 

underdrain of outfall protection 

— Consider seasonal operation 

— Provide ice storage volume 

— Cold-tolerant vegetation 

— Not recommended in 

arid areas and of 

limited use in semiarid areas 

Wetlands 

Size of drainage area: Moderate to large 

Site requirements: Poorly drained soils, 

space may be limiting 

Maintenance burdens: Annual harvesting 

of vegetation 

Longevity: High 

— Protect inlet/outlet pipes 

— Use large-diameter (> 8 in) gravel in 

underdrain of outfall protection 

— Consider seasonal operation 

— Provide ice storage volume 

— Cold-tolerant vegetation 

— Not recommended in 

arid areas and of 

limited use in semiarid areas 

Table 5.8 presents pollutant removal efficiency statistics for the management practices discussed 

in this section. These values originate from the National Pollutant Removal Performance 

Database for Stormwater BMPs (Caraco and Winer, 2000). The database was compiled through 

a comprehensive literature search focusing on runoff treatment practice monitoring sites from 

1990 to present. In addition, approximately 60 previously collected monitoring studies from 

1977 and 1989 were included in the database. All 139 studies meet the two following criteria: 

(1) the researchers used automated equipment that enabled flow or time-based composite 

samples; and (2) they documented the method used to compute removal efficiency. With respect 

to the number of storms sampled, more than three-quarters of the studies were based on five or 

more storm samples. The sample size was not reported in the remaining studies. 

5-58 
Management Measure 5: New Development Runoff Treatment 

Table 5.8: Effectiveness of management practices for runoff control (adapted from Caraco 

and Winer, 2000). 

Runoff Treatment Median Pollutant Removal (Percent) 

or Control Practice 

Category or Type 

No. of 

studies TSS TP OP TN NOx Cu Zn 

Quality Control Pond 3 3 19 N/A 5 9 10 5 

Dry Extended Detention Pond 6 61 20 N/A 31 -2 29 29 

Dry Ponds 9 47 19 N/A 25 3.5 26 26 

Wet Extended Detention Pond 14 80 55 69 35 63 44 69 

Multiple-Pond System 1 91 76 N/A N/A 87 N/A N/A 

Wet Pond 28 79 49 39 32 36 58 65 

Wet Ponds 43 80 51 65 33 43 57 66 

Shallow Marsh 20 83 43 66 26 73 33 42 

Extended Detention Wetland 4 69 39 59 56 35 N/A -74 

Pond/Wetland System 10 71 56 37 19 40 58 56 

Submerged Gravel Wetland 2 83 64 14 19 81 21 55 

Wetlands 36 76 49 48 30 67 40 44 

Organic Filter 7 88 61 30 41 -15 66 89 

Perimeter Sand Filter 3 79 41 68 47 -53 25 69 

Surface Sand Filter 7 87 59 N/A 31.5 -13 49 80 

Vertical Sand Filter 2 58 45 21 15 -87 32 56 

Bioretention 1 N/A 65 N/A 49 16 97 95 

Filtering Practicesa 18 86 59 57 38 -14 49 88 

Infiltration Trench 3 100 42 100 42 82 N/A N/A 

Porous Pavement 3 95 65 10 83 N/A N/A 99 

Ditchesb 9 31 -16 N/A -9 24 14 0 

Grass Channel 3 68 29 32 N/A -25 42 45 

Dry Swale 4 93 83 70 92 90 70 86 

Wet Swale 2 74 28 -31 40 31 11 33 

Open Channel Practices 9 81 34 1.0 84 31 51 71 

Oil-Grit Separator 1 -8 -41 40 N/A 47 -11 17

Shaded rows show data for groups of practices (i.e., dry ponds include quality control ponds and dry extended detention ponds).

Numbers in italics are based on fewer than five data points.

 a Excludes vertical sand filters 

b

 Refers to open channel practices not designed for water quality. 

TSS=total suspended solids, TP=total phosphorus, OP=ortho-phosphorus, TN=total nitrogen, NOx=nitrate and nitrite nitrogen, Cu=copper, 

Zn=zinc.

Strecker et al. (2000) identified problems with comparing different management practice 

effectiveness studies. They suggested that inconsistent study methods, lack of associated design 

information, and multiple reporting protocols make wide-scale assessments of management 

practices difficult. Also, differences in monitoring strategies and data evaluation methods 

contribute significantly to the wide range of reported management practice effectiveness. 

EPA recognizes that 80 percent TSS removal efficiency cannot be achieved for each storm event 

and understands that TSS removal efficiency will fluctuate above and below 80 percent for 

individual storms. Researchers have noted that efficiency estimation is often based on pollutant 

loads into and out of the management practice on a storm-by-storm basis. Therefore, a multiplestudy analysis or summary is based on the assumption that all storms are equal when computing 

average pollutant removal. Storm-by-storm comparisons are probably not effective because 

many storms are not large enough to displace the permanent pool volume. They recommend that 

effectiveness be evaluated using statistical characterizations of the inflow and outflow 

5-59 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

concentrations because if enough samples are collected, total loads into and out of the 

management practice can be used reliably. 

Strecker et al. (2000) also analyzed the use of effluent data to measure the influence of certain 

design criteria on management practice efficiency. Some studies suggest that management 

practices can only treat runoff to a specified pollutant concentration. However, if relatively clean 

water enters a practice, performance data based on removal efficiency might not fully 

characterize whether the practice is well designed and effective. Therefore, pollutant removal 

efficiency, when it is expressed as percent removal, might not be an accurate representation of 

Verifying the Performance of Environmental Technologies

EPA’s Environmental Technology Verification (ETV) Program, which began in October 1995, was 

instituted to verify the performance of innovative technical solutions to problems that threaten human 

health and the environment. ETV was created to significantly accelerate the entrance of new 

environmental technologies into the domestic and international marketplaces. The program operates 

through public and private testing partnerships to evaluate the performance of environmental 

technology in all media, including air, water, soil, ecosystems, waste, pollution prevention, and 

monitoring. More information about the ETV Program is available at http://www.epa.gov/etv (USEPA, 

2001b). 

Another method for evaluating technology is the Environmental Technology Evaluation Center 

(EvTEC), which was established by the Civil Engineering Research Foundation (CERF) through 

EPA’s ETV Program. EvTEC is an independent, market-based approach to technology verification 

and was established to accelerate the adoption of environmental technologies into practice. More 

information about EvTEC is available at http://www.cerf.org/evtec (CERF, 2001). 

EPA and NSF International, an independent, nonprofit testing organization, have developed a testing 

protocol to determine the viability of runoff treatment technologies and other wet weather flow controls, 

including runoff, combined sewer overflow (CSO), and sanitary sewer overflow (SSO). NSF 

International will also test and verify high-rate separation/clarification and high-rate disinfection 

technologies, flow monitoring equipment, and wet weather models. 

Participants in the study include vendors who want to demonstrate the effectiveness of their 

technologies. Results of the pilot will be useful to a variety of stakeholders including municipalities, 

businesses, vendors, consulting engineers, and regulatory agencies. Once verification reports have 

been completed, vendors may use the results in their marketing efforts. Results will be made publicly 

available through EPA’s and NSF’s Web sites at http://www.epa.gov/etv and 

http://www.nsf.org/business/ETV_EPA_NSF/index.asp?program=ETVEPANSF, respectively. More 

information about the program is available at http://www.wateronline.com/ 

content/news/article.asp?docid={17DDF263-29B8-11D5-A770-00D0B7694F32} (Water-Online, 2001).

The American Society of Civil Engineers, in cooperation with EPA, has compiled the International 

Stormwater Best Management Practices Database, which contains performance data from more than 

200 management practice studies. Information provided for the management practices includes test 

site location, researcher contact data, watershed characteristics, regional climate statistics, 

management practice design parameters, monitoring equipment types, and monitoring data such as 

precipitation, flow, and water quality. More information on the database’s purpose, design, and 

documentation can be found at http://www.bmpdatabase.org/. 

International Stormwater Best Management Practices Database

5-60 
Management Measure 5: New Development Runoff Treatment 

how well a management practice is performing. Although more research is necessary to 

accurately determine the effectiveness of management practices, Strecker et al. recommend that 

standard methods and detailed guidance on data collection be used to improve data 

transferability. 

Table 5.9 presents information concerning the costs associated with selected structural practices. 

The sources of these data are publicly available articles (some are a compilation of numerous 

studies). 

Table 5.9: Costs of selected management practices (Claytor and Schueler, 1996; Brown and 

Schueler, 1997). 

Management Practice Construction Costsa Useful Life (years) Total Annual Costs 

Infiltration basinb

 Average 

 Report range 

 Probable range 

$0.55/ft3

 storage 

$0.22–$1.31/ft3

$0.44–$0.76/ft3

25c

– 

– 

– 

$0.03–$0.05/ft3

– 

Infiltration trenchb

 Average 

 Report range 

 Probable range 

$4.36/ft3

 storage 

$0.98–$10.04/ft3

$2.73–$8.18/ft3

10c

– 

– 

– 

$0.03–$0.10/ft3

– 

Infiltration practicesd

 Average 

 Report range 

$2.99/ft3

 storage 

$2.13-4.27/ft3

 storage 

– 

– 

– 

– 

Vegetated swalesb

Established from seed 

 Average 

 Report range 

Established from sod 

 Average 

 Report range 

$7.09/linear ft 

$4.91–$9.27/linear ft 

$21.82/linear ft 

$8.73–$54.56/linear ft 

50e

– 

50e

– 

$1.09/linear ft 

– 

$2.18/linear ft 

– 

Porous pavementb

 Average 

 Report range 

$1.64/ft2

$1.09-$2.18/ft2

10f

– 

$0.16/ft2

– 

Concrete grid pavementb

 Average 

 Report range 

$1.09/ft2

$1.09–$2.18/ft2

20 

– 

$0.05/ft2

– 

Filtration basinsb

 Average (probable) 

 Report range 

 Probable range 

$5.46/ft3

 storage 

$1.09–12.00/ft3

$2.18–9.82/ft3

25g

– 

– 

– 

$0.11–$0.87/ft3

– 

Bioretention practicesd

 Average $6.83/ft3

 storage – – 

Filtration practicesd

 Average 

 Range 

$2.63/ft3

 storage 

$2.13-6.40/ft3

 storage 

– 

– 

– 

– 

Water quality inletb,h

 Average 

 Report range 

 Probable range 

$2,182 each 

$1,200–3,273 each 

– 

50 

– 

– 

$164 each 

– 

– 

Water quality inlet with 

sand filterb,h

 Average (probable) 

$10,900/drainage acre 50 $764/drainage acre 

5-61 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Table 5.9 (continued). 

Management Practice Construction Costsa Useful Life (years) Total Annual Costs 

Oil/grit separatorb,h 

 Average 

 Report range 

$19,640/drainage acre 

$16,370–$21,820/drainage 

acre 

50 

– 

$1,091/drainage acre 

– 

Stabilization with ground 

coverb,h 

From existing vegetation 

 Average 

 Report range 

From seed 

 Average 

 Report range 

From seed and mulch 

 Average 

 Report range 

From sod 

 Average 

 Report range 

$0 

– 

$436/acre 

$218–$1,091/acre 

$1,637/acre 

$872–$3,819/acre 

$12,330/acre 

$4,910–$52,375/acre 

50 

– 

50 

– 

50 

– 

50 

– 

Natural: $109/acre 

Managed: $873/acre 

Natural: $131/acre 

Managed: $900/acre 

Natural: $218/acre 

Managed: $982/acre 

Natural: $764/acre 

Managed: $1,528/acre 

Ext. Detention Dry 

Pondb,h

 Average 

 Report range 

 Probable range 

$0.55/ft3

 storage 

$0.05–$3.49/ft3

$0.10–$5.46/ft3

50 

– 

– 

– 

$0.008–$0.33/ft3

– 

Wet Pond and Extended 

Detention Wet Pondb

Storage vol. < 1 million ft3

Average 

Report range 

Probable range 

Storage vol. > 1 million ft3

Average (probable) 

Report range (probable) 

Probable range 

$0.55/ft3

 storage 

$0.05–$1.09/ft3

$0.55–$1.09/ft3

$0.27/ft3

 storage 

$0.05–$0.55/ft3

$0.11–$0.55/ft3

50 

– 

– 

50 

– 

– 

$0.009–$0.08/ft3

– 

– 

– 

$0.009–$0.08/ft3

– 

a

Costs updated using the Bureau of Labor Statistics Inflation Calculator. 

b

Claytor and Schueler, 1996. 

c

References indicate the useful life for infiltration basins and infiltration trenches at 25-50 and 10-15 years, respectively. Because of the high 

failure rate, infiltration basins are assumed to have a useful life span of 25 years and infiltration trenches are assumed to have a useful life span of 

10 years. 

d

Brown and Schueler, 1997. 

e

Useful life is assumed to equal the life of the project, assumed to be 50 years. 

f

No information was available for porous pavement. It is assumed to be similar to infiltration trenches. 

g

No information was available for filtration basins. It was assumed to be similar to infiltration basins. 

h These practices do not meet the 80 percent TSS removal, thus it is recommended that they be used with other management practices in a 

treatment train.

5.5 Managing Structural Controls to Reduce Mosquito-Breeding 

Habitat 

In recent years, concern has been raised that storm water management facilities have been 

breeding grounds for mosquitoes (Conlon, 2002). This is a public health concern because 

mosquitoes are known vectors for disease-causing arboviruses such as malaria, yellow fever, 

dengue fever, St. Louis encephalitis, and West Nile virus, to name a few. The relationship 

5-62 
Management Measure 5: New Development Runoff Treatment 

between storm water management and mosquito breeding exists because the presence of standing 

and sometimes stagnant water facilitates the two aquatic stages of a mosquito’s life cycle—the 

egg and larval stages. 

Not all mosquito species are vectors for disease, but control is still warranted because, even if not 

a health risk, mosquitoes are considered a nuisance. Mosquito species have different habitat 

preferences, and two basic groups can breed in the urban environment: permanent water species 

and floodwater species (Metzger et al., 2002). Permanent water species would be likely to 

propagate in storm water management facilities that always contain water, such as wet detention 

ponds and constructed wetlands. Floodwater species would likely inhabit “dry” systems such as 

extended detention dry ponds that have fluctuating water levels. 

This issue has caused a fair amount of controversy because mosquito-breeding habitats are 

prevalent in urban and suburban environments. Metzger et al. (2002) identified a few of the 

numerous manmade mosquito-breeding habitats in urban and suburban environments: 

Urban environments provide mosquitoes with a vast array of new habitats: humid 

and arid, above and below ground, small water-holding containers and large 

ponds, polluted and clean water. Aquatic habitats are found around people's 

homes (birdbaths, jars, flower pots, neglected pools and Jacuzzis and clogged rain 

gutters), in unregulated waste dumps (used tires, barrels, bottles, and cans), in 

parks (ponds, lakes, and streams), and in the city's own infrastructure (storm 

drains, sewer systems, catch basins, and culverts). Many of these sources are 

replenished frequently by stormwater and urban runoff (e.g., irrigation, washing 

cars). Adding to this, increasingly stringent urban stormwater runoff regulations 

have recently mandated the construction of structural practices for both volume 

reduction and pollution management, many of which have created additional 

sources of standing water. This abundance of habitats has favored mosquitoes and 

allowed many species to greatly expand their range and increase in number. 

Although storm water management facilities are not the sole source of standing water, public 

concern has raised the question of how these facilities can be managed, redesigned, or otherwise 

modified to reduce the creation of disease vectors close to urban population centers. 

The California Department of Health Services’ Vector-Borne Disease Section (2002), in 

cooperation with the California Department of Transportation (Caltrans), undertook a study to 

evaluate retrofit opportunities for storm water management. Part of this study investigated the 

mosquito production of 37 structural management practices in southern California. Eight 

categories of practices were constructed and examined as part of the study: (1) biofiltration strips 

and swales; (2) filtration devices (Austin-type and Delaware-type sand media filters, multichambered treatment train sand media filters, and a proprietary canister filter); (3) extended 

detention basins; (4) infiltration devices (basins and trenches); (5) continuous deflective 

separators (CDSs); (6) an oil/water separator; (7) drain-inlet inserts; and (8) a constructed 

wetland (retention pond). The study consisted of comprehensive surveillance and monitoring of 

each practice for mosquito production, as well as follow-up monitoring after modifications had 

been made to reduce the potential to produce mosquitoes. Of the eight different technologies 

implemented by Caltrans, those that maintained permanent sources of standing water in sumps or 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

basins (MCTT, CDS, and the retention pond) provided excellent habitat for immature 

mosquitoes and frequently supported large populations relative to other structural designs. In 

contrast, practices designed to drain rapidly (i.e., biofiltration swales and strips, Austin-type sand 

media filters, infiltration basins and trenches, and extended detention basins) provided lesssuitable habitats and rarely harbored mosquitoes. 

The project was expanded to a nationwide investigation using phone and mail surveys and site 

visits to 150 agencies in 28 states. Of the 72 agencies that completed a questionnaire, 86 percent 

reported mosquito production associated with storm water management facilities. The survey 

found that inadequate maintenance resulted in accumulation of trash and other constituents (e.g., 

sediment, vegetation, organic debris). 

The Southwest Florida Water Management District conducted a study to determine the extent to 

which storm water management facilities were breeding mosquitoes and offer recommendations 

for minimizing mosquito production (Livingston, no date). After examining more than 200 

management practices with both permanent pools and intermittent pools, they found that 76 

percent of all practices were mosquito productive, and that 66 percent of the permanently 

flooded practices and 69 percent of the intermittently flooded practices bred mosquitoes. Larval 

density was smaller and more dispersed in wet detention systems than in intermittently flooded 

systems. The wet detention systems that did not breed mosquitoes shared a paucity of vegetation, 

abundant fish, and good aeration. The intermittently flooded dry detention pond systems that did 

not produce mosquitoes were those that drained or dried within 72 hours. 

The Florida researchers also investigated several pesticides and found them to be between 91 and 

100 percent effective at controlling existing larval infestations in intermittently flooded systems 

within 24 hours of treatment, although one treatment in a system with high organic content was 

found to be ineffective against dense larval populations. The researchers also found that 

sustained-release materials such as pellets were effective for up to five weeks after application, 

whereas short-term controls required regular application. 

Regular monitoring for mosquito adults and larvae, retrofitting and maintenance of practices to 

reduce the likelihood for breeding, and pesticide application where needed are the three key 

actions for eliminating mosquito breeding in storm water facilities. The Centers for Disease 

Control and Prevention discussed the role of pesticides that kill adult mosquitoes (adulticides) in 

mosquito management and recommended that their use be incorporated into an integrated pest 

management program that includes surveillance, source reduction, chemical control (larvicide 

and adulticide), biological control, and public relations and education (Rose, 2001). 

Surveillance programs track diseases in bird populations, vector-borne pathogens in mosquitoes, 

mosquito populations, larval habitats, mosquito traps, biting counts, and reports by the public 

(Rose, 2001). Control activities are initiated when threshold populations are exceeded, and 

predictions are made from seasonal records and weather data. 

Source reduction entails eliminating or altering larval habitats. This can be achieved through 

public education campaigns, with outreach to both children and adults. Additionally, state and 

local mosquito control agencies can alter the hydrology of open water and marshy areas to 

reduce or prevent the proliferation of mosquito larvae. Rose (2001) suggests techniques in which 

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Management Measure 5: New Development Runoff Treatment 

mosquito-producing areas in marshes are connected by shallow ditches to deep-water habitats to 

allow drainage or fish access, and minimally flooding the marsh during the summer but flapgating impounded areas to reintegrate them to the estuary for the rest of the year. 

Biological control can be achieved using various predators such as dragonfly nymphs and 

predacious mosquitoes (Rose, 2001). Mosquito fish are the most commonly used agents for 

biological control because they are easily reared, although they also feed on non-target species. 

Other types of organisms that might be used for mosquito control include several fish types other 

than Gambusia, as well as fungi, protozoans, nematodes, and predacious copepods. 

It is essential that storm water managers and public works crews who maintain storm water 

management facilities be educated in integrated pest management. They should be trained to 

identify design flaws or maintenance needs that might create mosquito-breeding habitat, and they 

should know the procedures for reporting and remedying the problem. Pesticide handlers should 

have the required training under the Federal Insecticide, Fungicide, and Rodenticide Act and all 

chemicals should be applied at rates recommended on the packaging. Treated areas should be 

monitored after application to determine the efficacy of the applications and identify where 

pesticide resistance might be occurring. 

There are steps that a storm water manager can take to reduce the likelihood that mosquitoes will 

breed in storm water management facilities. From a design standpoint, most management 

practices other than wet retention ponds are intended to drain within 72 hours. This is a safe 

drainage time because mosquitoes need at least that long for their aquatic life stages. 

Additionally, Metzger et al. (2002) found that several design features of storm water 

management practices contributed to vector production, including the use of sumps, catch basins, 

or spreader troughs that did not drain completely; the use of loose riprap that could hold small 

amounts of water; pumps or motors designed to “automatically” drain water from structures; and 

effluent pipes with discharge orifices prone to clogging because of their small diameter. 

Livingston (no date) recommends the following design considerations to minimize mosquitoes: 

— Designs must be based on site characteristics to ensure that the most appropriate type of 

storm water management facility is selected. Vegetated dry retention systems should be 

designed as off-line systems. They should be used only where the soil and water table 

conditions will assure that the system drains or dries within 24 to 36 hours, and where the 

seasonal high water table is at least two feet below the bottom of the system. If on-line 

retention areas are used, they should be designed to be dry within three days of a 25-year, 

24-hour storm. 

— Dry retention systems need to be carefully constructed to avoid compacting the soil and 

reducing its infiltration rate. They also should have flat bottoms to avoid having areas of 

standing water. 

— To minimize decaying organic matter, the grass or other vegetation in dry retention areas 

should be regularly mowed and the clippings removed and composted. 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

— The littoral zone of wet detention areas should be planted with aquatic macrophytes such 

as Sagittaria latifolia (duck potato), Sagittaria lancifolia (lance-leaf arrowhead), Juncus 

effusus (soft rush), Pontedaria lancifolia (pickerelweed), Juncus roemerianus (needle 

rush), Scirpus californicus (giant bulrush), and Scirpus validus (soft stem bulrush). 

Cattails (Typha spp.) should never be planted in or allowed to remain in storm water 

systems as they grow very profusely, creating a large quantity of decaying matter. 

— Wet detention systems should be stocked with native Gambusia spp. minnows (mosquito 

fish) to foster biological predation of mosquito larvae. If needed because of site 

conditions, a “minnow sump” should be excavated in the deepest part of the pond to 

assure permanent habitat and survival during droughts. 

— Sustained-release larvicides should be used whenever necessary with systems known to 

be mosquito productive treated before the onset of the mosquito life cycle. 

— Regular inspection and maintenance of storm water systems is essential to ensure that the 

facility drains as designed. Such maintenance involves removing submerged vegetation 

and clearing sediments away from inlets, outlets, and the bottom of the pool or holding 

area. 

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5.6 Information Resources 

The Technology Review: Ultra-Urban Stormwater Treatment Technologies (Brueske, 2000) was 

compiled to provide a review of “ultra-urban” storm water treatment technologies. These types 

of technologies are designed to remove pollutants from runoff in highly developed areas where 

land values are high and available space is limited. Ultra-urban technologies differ from 

traditional runoff treatment controls in that they are very compact and can be retrofitted into 

existing runoff collection systems. The document specifically analyzes four types of treatment 

technologies: gravity separation, swirl concentration, screening, and filtration. Technology 

review findings were then used to develop a design protocol for selecting and installing ultraurban treatment technologies. This document can be downloaded in PDF format from 

http://depts.washington.edu/cuwrm/research/ultraurbn.pdf. 

The California Department of Transportation (Caltrans) prepared two handbooks on storm water 

quality as an updated version of the Construction Contractor’s Guide and Specifications. These 

new manuals are the Construction Site Best Management Practices (BMPs) Manual and the 

Storm Water Pollution Prevention Plan (SWPPP) and Water Pollution Control Program 

(WPCP) Preparation Manual. The two manuals provide background information on Caltrans’ 

program to control water pollution, offer instructions for selecting and implementing 

construction site best management practices, and help to standardize the process for preparing 

and implementing the SWPPP and the WPCP. Caltrans requires contractors to prepare and 

implement a program to control water pollution during the construction of all projects. The 

manuals are available for download at 

http://www.dot.ca.gov/hq/construc/stormwater/manuals.htm. 

The Milwaukee Metropolitan Sewerage District developed a manual entitled “Surface Water and 

Storm Water Rules Guidance Manual” in 2002 that is available on their Web site at 

http://www.mmsd.com/stormwaterweb/Startpg.htm. The document includes an extensive 

discussion of the principles of storm water management, descriptions of both structural and 

nonstructural measures to control storm water, and sizing procedures for detention basins, among 

other topics. 

In August 1998 the Center for Watershed Protection published Better Site Design: A Handbook 

for Changing Development Rules in Your Community. The publication covers everything from 

basic engineering principles to “actual versus perceived” barriers to implementing better site 

designs. The handbook outlines 22 guidelines for better developments and provides a detailed 

rationale for each principle. Better Site Design also examines current practices in local 

communities, details the economic and environmental benefits of better site designs, and presents 

case studies from across the country. The document is available for purchase from the Center for 

Watershed Protection at http://www.cwp.org/. 

In 2000 the Maryland Department of the Environment published the Maryland Stormwater 

Design Manual. The manual was designed to protect Maryland waters from the adverse impacts 

of urban runoff, to provide design guidance on the most effective structural and nonstructural 

management practices for development sites, and to improve the quality of management 

practices that are recommended by the state of Maryland. The first volume of the manual 

contains information on management practice siting and design on new development sites to 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

comply with Maryland’s 14 storm water performance standards. A unique feature is the use of 

storm water credits for rewarding innovative storm water management designs. The second 

volume contains detailed technical information on runoff control practices, including step-bystep design examples. Both volumes are available for download at 

http://www.mde.state.md.us/environment/wma/stormwatermanual. 

In 1995 the Metropolitan Washington Council of Governments (MWCOG) published Site 

Planning for Urban Stream Protection, which presents a watershed approach to site planning and 

examines new ways to reduce pollutant loads and protect aquatic resources through nonstructural 

practices and improved construction site planning. The book also provides insight into the 

importance of imperviousness, watershed-based zoning, concentration of development, 

headwater streets, stream buffers, green parking lots, and other land planning topics. The 

document is available for purchase from MWCOG at http://www.mwcog.org/ic/95708.html. 

The Texas Nonpoint SourceBOOK is an interactive Web tool that was designed to provide runoff 

management information to public works professionals and other interested parties in Texas and 

elsewhere. This site, which can be accessed at http://www.txnpsbook.org/, includes a beginner’s 

guide to urban nonpoint source management issues, a discussion of water quality issues in Texas, 

elements of a storm water management program, information on storm water utilities, tips for 

assessing and selecting management practices, a comprehensive listing of links to other sites, 

frequently asked questions, and nonpoint source news. 

In 1999 the Denver Urban Drainage and Flood Control District published the Urban Storm 

Drainage Criteria Manual. The manual was designed to provide guidance for local jurisdictions, 

developers, contractors, and industrial and commercial operators in selecting, designing, 

implementing, and maintaining management practices to improve runoff quality. The third 

volume of this manual is primarily targeted at developing and redeveloping residential and 

commercial areas. The manual is available for purchase at http://www.udfcd.org/. 

In 1995 EPA published Economic Benefits of Runoff Controls (EPA-841-S-95-002), which 

contains a description of studies that document increases in property values and rental prices 

when properly designed runoff controls are used as visual amenities. The document is available 

for download from EPA’s National Environmental Publications Internet Site (NEPIS) at 

http://www.epa.gov/ncepihom/nepishom. 

EPA published the Preliminary Data Summary of Urban Storm Water Best Management 

Practices in 1999. The document summarizes existing information and data on the effectiveness 

of management practices to control and reduce pollutants in storm water. The report also 

provides a synopsis of what is currently known about the expected costs and environmental 

benefits of management practices, and identifies information gaps. The document is available for 

download in PDF format at http://www.epa.gov/ost/stormwater/usw_a.pdf. 

In 1992 the Washington State Department of Ecology published its Stormwater Management 

Manual for the Puget Sound Basin. The manual is divided into five documents: Volume I: 

Minimum Technical Requirements; Volume II: Construction Stormwater Pollution Prevention; 

Volume III: Hydrologic Analysis and Flow Control Design; Volume IV: Source Control BMPs; 

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Management Measure 5: New Development Runoff Treatment 

and Volume V: Runoff Treatment BMPs. All five volumes are available for download at 

http://www.ecy.wa.gov/biblio/9911.html. 

The Washington State Department of Ecology’s Water Quality Program has developed a 

Nonpoint Source Pollution home page. This Web site, accessible at 

http://www.ecy.wa.gov/programs/wq/nonpoint, contains nonpoint source program information, 

posters, resources, and references. The Department of Ecology has also made available a copy of 

the draft of Instream Flows in Washington State: Past, Present, and Future. The document is 

available at http://www.olympus.net/community/dungenesswc/InstreamFlowversion12.PDF. 

The Metropolitan Council of St. Paul/Minneapolis developed the Urban Small Sites Best 

Management Practices (BMP) Manual to provide assistance to communities in planning for 

storm water management for sites of less than 5 acres located in cold climates. The document 

focuses on low-impact development practices that promote the restoration and preservation of 

natural hydrology. The manual includes information on the selection of BMPs and model storm 

water ordinances and contains a regulatory analysis for watershed programs. The document is 

available at http://www.metrocouncil.org/environment/Watershed/bmp/manual.htm. 

An excellent discussion of the design of infiltration techniques in limestone/carbonate bedrock 

areas can be found in a new design manual developed for the Lehigh Valley Planning 

Commission (LVPC) by Cahill Associates. The manual, Technical Best Management Practice 

Manual and Infiltration Feasibility Report: Infiltration of Stormwater in Areas Underlain by 

Bedrock in the Little Lehigh Creek Watershed, is available from the LVPC at 961 Marcon 

Boulevard, Suite 310, Allentown, Pennsylvania, 18109, 1-888-627-2626 (toll free), 

lvpc@lvpc.org. 

The Virginia Municipal League published an article titled “Stafford County helps pioneer low 

impact design movement” describing the process by which Stafford County, Virginia, 

incorporated low-impact design into its development codes. The article includes links to Builders 

for the Bay, an organization that provides assistance to local communities wishing to update their 

codes, as well as several other helpful resources for communities. The article can be downloaded 

at http://www.vml.org/VTC/VTC3908-2.html. 

The American Mosquito Control Association’s Web site, located at http://www.mosquito.org/, 

offers information about mosquitoes and their control along with links, frequently asked 

questions, and West Nile virus information. 

American Rivers developed a report on low impact development techniques for the Great Lakes 

region called Catching the Rain: A Great Lakes Resource Guide for Natural Stormwater 

Management. The report includes an overview of many runoff control techniques, including pros 

and cons of each practice. The report can be downloaded in PDF format from the American 

Rivers Web site at www.americanrivers.org (visit the “Resources” link and choose to view a 

complete list of publications). 

The Villanova University Stormwater Partnership conducts research on management practices to 

control urban runoff. The organization has established a “Stormwater BMP Park” with a 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

constructed wetland, a biofiltration traffic island, and a porous concrete site. Research results and 

outreach materials can be found at http://www3.villanova.edu/VUSP/. 

The EPA “Final Action for Effluent Guidelines and Standards for the Construction and 

Development Category” can be found at http://www.epa.gov/fedrgstr/. The Technical 

Development Document (EPA-821-B-04-001), which contains information on costs and 

technologies, is available from US EPA/NSCEP. P.O. Box 42419, Cincinnati, Ohio 45242-2419, 

(800) 490-9198 or http://www.epa.gov/waterscience/guide/construction. 

EPA’s The Use of Best Managment Practices (BMPs) in Urban Watersheds evaluates design, 

effectiveness, and cost considerations for storm water management practices. The document 

canbe downloaded in PDF format from 

http://www.epa.gov/ORD/NRMRL/pubs/600r04184/600r04184.pdf (cover and table of contents) 

and http://www.epa.gov/ORD/NRMRL/pubs/600r04184/600r04184chap1.pdf (Chapters 1–6). 

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Management Measure 5: New Development Runoff Treatment 

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ASTM International. 2002. Standard Test Methods for Determining Sediment Concentration in 

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Baladès, J-D, M. Legret, and H. Madiec. 1995. Permeable Pavements: Pollution Management 

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Barraud, S., A. Gautier, J. P. Bardin and V. Riou. 1999. The Impact of Intentional Stormwater 

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of permeable pavement systems. Water Research 37(18): 4,369–4376. 

Brown, W., and T. Schueler. 1997. The Economics of Stormwater BMPs in the Mid-Atlantic 

Region: Final Report. Prepared by the Center for Watershed Protection, Ellicott 

City, MD, for the Chesapeake Research Consortium, Edgewater, MD. 

Brueske, C.C. 2000. Technology Review: Ultra-Urban Stormwater Treatment Technologies. 

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Caraco, D., and R. Claytor. 1997. Stormwater BMP Design Supplement for Cold Climates. 

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Caraco, D., and R. Winer. 2000. Updated National Pollution Removal Performance Database 

for Stormwater Treatment Practices. Center for Watershed Protection, Ellicott City, MD. 

Carr, R.W., E. Carolyn, and S.G. Walesh. 1999. Street Surface Storage for Control of Combined 

Sewer Surcharge: Case Studies. American Society of Civil Engineers 26th Annual Water 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Center for Watershed Protection (CWP). 1996. Irreducible Pollutant Concentrations Discharged 

from Urban BMPs. Watershed Protection Techniques 2(2): 369–371. 

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Enhancing Your Rain Garden. Prince George’s County Department of Environmental 

Resources, Landover, MD. 

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Management Measure 5: New Development Runoff Treatment 

Dillaha, T.A., R.B. Renear, S. Mostaghimi, and D. Lee. 1989. Vegetative Filter Strips for 

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Water: Water Quality and Fate of Heavy Metals. Water Science and Technology 39(2): 

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Legret, M., M. Nicollet, P. Miloda, V. Colandini and G. Raimbault. 1999. Simulation of Heavy 

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Livingston, E.H. No date. Stormwater Management Systems: A Source of Mosquitoes?? Florida 

Department of Environmental Protection, Stormwater/Nonpoint Source Management 

Section, Tallahassee, FL. 

MacRae, C.R. and A.C. Rowney. No date. The Role of Moderate Flow Events and Bank 

Structure in the Determination of Channel Response to Urbanization. Kingston, Ontario, 

Canada. 

MacRae, C.R. No date. Experience from Morphological Research on Canadian Streams: Is 

Control of the Two-Year Frequency Runoff Event the Best Basis for Stream Channel 

Protection? Kingston, Ontario, Canada. 

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Program. Maryland Department of Natural Resources, Annapolis, MD. 

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5-80 
Management Measure 6: New and Existing On-Site Wastewater Treatment Systems 

MANAGEMENT MEASURE 6 

NEW AND EXISTING ON-SITE WASTEWATER TREATMENT 

SYSTEMS 

6.1 Management Measure 

Develop or maintain on-site wastewater treatment system (OWTS) permitting and installation 

programs that adequately protect surface water and ground water quality. Programs should 

include: 

— A process to identify and protect sensitive areas (e.g., wellhead protection zones, 

nitrogen/phosphorus limited waters, shellfish habitat) and ensure that cumulative 

hydraulic discharges and mass pollutant loads from on-site systems do not impair surface 

or ground water; 

— System selection, siting, design, and installation based on performance requirements, 

prescriptive technologies, protective setbacks, and separation distances that protect 

surface water and ground water resources; 

— Education, training, licensing, and/or certification programs for system designers, site 

evaluators, permit writers, installers, inspectors, and other service providers; and 

— Inspections of new on-site systems during and immediately following 

construction/installation to ensure that design and siting criteria are applied appropriately 

in the field. 

Establish and implement management programs to ensure that newly permitted and existing onsite wastewater treatment systems are operated and maintained properly to prevent the 

impairment or degradation of surface and/or ground waters. On-site system operation and 

maintenance programs should include: 

— System inventories and assessments of maintenance needs that provide management 

information regarding the types of systems in use and their location, capacity, installation 

date, owner, date of last inspection/service, and other data needed to support operation 

and maintenance oversight activities. 

— Policies to ensure that on-site systems are managed, operated, and maintained to prevent 

degradation and impairment of surface and ground waters. These policies should include 

adequate authority to conduct inspections, revoke operating permits, and require 

pumping, repair, replacement, upgrade, or modification technologies when conditions 

indicate that surface and/or ground water resources might be adversely affected (e.g., 

eutrophication of surface waters, microbial or nitrate contamination of ground water). 

— Periodic inspection and/or monitoring requirements to ensure that on-site systems are 

functioning properly. Inspection and monitoring programs should consider hydraulic, 

hydrologic, and mass pollutant loading impacts at both the site and watershed scales. 

— Requirements to ensure that residuals pumped from the tank (i.e., septage) are reused or 

disposed of in a manner that does not present significant risks to surface waters or ground 

water resources. 

6-1 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

6.2 Management Measure Description and Selection 

6.2.1 Description 

When properly planned, designed, installed, operated, and maintained, OWTSs (also referred to 

as septic systems) can effectively remove or treat contaminants such as pathogens, biochemical 

oxygen demand (BOD), and nutrients in human sewage. However, many on-site systems are 

failing because of age, inappropriate design, hydraulic/pollutant overloading, or poor 

maintenance (see Table 6.1). Detrimental impacts from on-site systems can occur when they are 

sited in sensitive ecological areas (such as wellhead protection zones, near nitrogen/phosphorus 

limited waters, or near beaches or shellfish habitat) or when they are installed at densities that 

exceed the hydraulic and hydrologic assimilative capacities of regional soils and aquifers. 

Pollutants of concern from on-site systems include pathogens, nitrogen compounds (e.g., 

nitrates), phosphorus, BOD, and other chemicals described in Table 6.2. 

Table 6.1: Common causes of OWTS failure. 

Type of failure Contributing causes 

Hydraulic Excessive hydraulic loadings to undersized systems, low soil permeability, excessive ponding at 

the infiltrative surface, poor maintenance. Increases in water usage over a period of years can 

exceed the design capacity of the wastewater treatment system. 

Organic Excessive organic loading from unpumped or sludge-filled tanks results in biomat loss of 

permeability (biomats are discussed further in Section 6.3.1.5.2, which describes subsurface 

wastewater infiltration systems). 

Soil depth to 

ground water 

table or 

bedrock 

Insufficient soil depths (i.e., soil thickness between the subsurface wastewater infiltration system 

[SWIS] and ground water tables, impermeable strata, or bedrock is less than the recommended 

depth for soil texture and structure). High ground water is deleterious to pathogen removal and 

hydraulic performance. 

System age Systems more than 25 to 30 years old. Systems less than 25 to 30 years old experience 

considerably fewer hydraulic failures. Failure rates can more than triple for older systems. 

Regular tank pumping and use of alternating SWISs can prolong system life indefinitely. 

Design failure Inappropriate system design for the site; failure to adequately consider or characterize wastewater 

strength and flow (average daily and/or peak flows); failure to identify and consider restrictive 

soil/rock layers (e.g., fragipan) or regional geology (e.g., karst features, creviced bedrock); failure 

to assess landscape position. 

System density Cumulative effluent load from all systems in watershed or ground water recharge area exceeds 

the hydrologic capacity of the area to accept and/or properly treat effluent.

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Management Measure 6: New and Existing On-Site Wastewater Treatment Systems 

Table 6.2: Pollutants of concern for OWTSs (adapted from Tchobanoglous and Burton, 

1991). 

Pollutant Reason for concern 

Pathogens Microorganisms such as parasites, bacteria, and viruses can cause communicable 

diseases through direct/indirect body contact or ingestion of contaminated water or 

shellfish. Pathogens pose a particular threat when partially treated sewage pools on 

ground surfaces or migrates to recreational waters. Transport distances for some 

pathogens in surface or ground waters can be significant. 

Nitrogen Nitrogen is a plant nutrient that can contribute to eutrophication and depletion of 

dissolved oxygen in surface waters, especially in estuaries and coastal embayments. 

Excessive nitrate-nitrogen in drinking water can cause methemoglobinemia in infants 

and complications for pregnant women. Livestock also can suffer health impacts from 

drinking water high in nitrate. 

Phosphorus Phosphorus is a plant nutrient that can contribute to eutrophication of inland fresh 

waters and some marine waters and eventually deplete dissolved oxygen. 

Household chemicals Chlorine, ammonia, and other cleaning compounds in high volumes may disrupt or 

disable biological activity in the septic tank. Wastes from hobby or craft activities 

(paints, solvents, etc.) and disposal of non-organic liquid wastes (old furniture polish, 

pesticides/herbicides, etc.) in onsite/cluster systems can have similar impacts. 

Pharmaceuticals and 

endocrine disruptors 

Disposal of large quantities of outdated antibiotics and other medicinal products in 

septic tank-based systems can impair or halt biological treatment processes. Disposal of 

products containing chemicals that disrupt endocrine system functions (e.g., regulation 

of metabolism, blood sugar, reproduction, embryonic development) in on-site systems 

might result in leaching of these chemicals into groundwater and surface waters and 

impair water quality and/or aquatic organisms, in some cases. Research on this issue, 

including toxicology, transport, and fate of potential endocrine disruptors, is ongoing 

(USEPA, 1998a; North Carolina Department Environment and Natural Resources, no 

date). 

Estimates of on-site system failure rates range from 5 to 25 percent and higher in some states 

(USEPA, 2001b), resulting in contamination of drinking water, beaches, shellfish beds, and 

surface water resources. In 1996 septic systems were a contributing source of pollution for more 

than one-third (36 percent) of the impaired miles of ocean shoreline surveyed. The National 

Oceanic and Atmospheric Administration (NOAA) reported in 1995 that the discharge of 

partially treated sewage from malfunctioning septic systems was identified as a principal or 

contributing factor in 32 percent of all harvest-limited growing areas (NOAA, 1995). 

In addition, ponds, lakes, and coastal embayments have been impaired by algal blooms caused in 

part by nutrient over-enrichment from failing OWTSs. For example, in Sarasota County, Florida, 

45,000 septic systems contribute four times as much nitrogen to Sarasota Bay as the city of 

Sarasota’s wastewater treatment plant. Septic systems are adding an estimated 1.5 million 

pounds of nitrogen per year to Florida’s Indian River Lagoon, causing a decrease in freshwater 

wetlands and commercial shellfish harvests (USEPA, 2003). 

States have identified OWTSs as the third most common contributor to ground water pollution 

and a significant threat to drinking water sources (Parsons Engineering Science, 2000). A 1999 

outbreak of gastroenteritis at the Washington County (New York) Fair was linked to a failing 

septic system at a nearby dormitory. A failed septic system was blamed for 46 cases of hepatitis 

A in Racine, Missouri, in 1992, and other states have reported both health and water resource 

impacts from poorly functioning OWTSs (Fobbs and Skala, 1992). 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Figure 6.1: Conventional on-site wastewater treatment system. 

OWTSs can generally be divided into two categories: conventional systems and alternative or 

innovative systems. 

Conventional systems (see Figure 6.1) consist of a septic tank and a subsurface soil absorption 

field, commonly called a subsurface wastewater infiltration system (SWIS). Buried in the 

ground, septic tanks are essentially watertight, single- or multiple-chamber sedimentation and 

anaerobic digestion tanks. They are designed to receive and pretreat domestic wastewater, 

mediate peak flows, and keep settleable solids, oils, scum, and other floatable material out of the 

SWIS. Wastewater effluent is discharged from the tank and passes through pipes to a series of 

underground perforated pipes that can be wrapped in a permeable synthetic material. From there, 

the partially treated effluent flows onto and through the soil infiltrative surface, and finally into 

the SWIS infiltration medium (i.e., soil). Treatment occurs in the septic tank, on and within the 

biomat that forms at the soil infiltrative surface, and in the soil (or other medium); it then 

continues as the effluent moves through the underlying soil (biomats are discussed further in 

Section 6.3.1.5.2, which describes subsurface wastewater infiltration systems). Treated effluent 

that is not drawn into plant roots, incorporated into microbial biomass, or evaporated ultimately 

reaches ground waters and possibly nearby surface waters. 

Alternative or innovative systems such as mound systems, fixed-film contact units, wetlands, 

aerobic treatment units (“package plants”), low-pressure drip applications, and cluster systems, 

are used in areas where conventional soil-based systems cannot provide adequate treatment of 

wastewater effluent. Areas that might not be suitable for conventional systems are those with 

nearby nutrient-sensitive waters, high densities of existing conventional systems, highly 

6-4 
Management Measure 6: New and Existing On-Site Wastewater Treatment Systems 

permeable or shallow soils, shallow water tables, large rocks or confining layers, and poorly 

drained soils. Alternative or innovative systems feature components and processes designed to 

promote degradation and/or treatment of wastes through biological processes, oxidation/ 

reduction reactions, filtration, evapotranspiration, and other processes. Cluster systems can be 

used to collect and treat wastewater from multiple facilities at a common site (e.g., lagoon, 

wetland, infiltration field). Alternative, innovative, and cluster systems often require individual 

septic tanks for each facility served to provide primary treatment and minimize fat, oil, grease, 

and solids loadings to secondary treatment units. (Note: Cluster systems that serve 20 or more 

people may be regulated by a federal, state, and/or local Underground Injection Control Program 

for Class V facilities. For more information, visit EPA’s Underground Injection Control Program 

Web site at http://www.epa.gov/safewater/uic.html.) 

Many states, tribes, and municipalities use a prescriptive approach to on-site system 

management. Such an approach assumes that a prescribed system design will adequately protect 

public health and water resources when installed at sites meeting established minimum 

requirements. Site evaluations are usually based on empirical approaches such as percolation 

tests and setback/separation distance requirements. 

These evaluations do not typically consider regional hydrology or the density and cumulative 

discharge of existing and planned treatment systems. They do not consider the overall 

assimilative capacity of regional soils and hydrology and do not assess complex relationships 

among soil characteristics, site conditions, wastewater composition, biological mechanisms, and 

regional climate (Otis and Anderson, 1994). A prescriptive approach is often restrictive and 

arbitrary and can be underprotective or overprotective of public health and water quality. 

A performance-based on-site system management approach does not require specifications for 

treatment methods or processes, but rather establishes treatment performance requirements for 

protecting human health and water resources. For example, this approach requires additional 

nitrogen removal in designated nutrient-sensitive areas without specifying the type of technology 

to be used (Code of Massachusetts Regulations, 1995). A report issued by the Maryland 

Department of the Environment and Maryland Office of Planning (2000) recommends 

installation of systems with enhanced nitrogen removal capabilities in designated “areas of 

special concern” to reduce nutrient loadings to the Chesapeake Bay and other sensitive waters. 

Under a performance-based approach, officials are free to consider the application of alternative 

and innovative on-site systems in addition to conventional systems. Systems are planned, 

designed, sited, and installed to achieve specified performance requirements within the context 

of regional and individual site conditions, rather than requiring site conditions to conform to the 

soils, slopes, and other needs of a restricted set of prescribed technologies. Performance-based 

on-site programs also include rigorous and ongoing system management, such as periodic 

inspections and required maintenance. Such a management approach can result in fewer system 

failures and greater protection of public health, surface waters, and ground water. 

EPA issued EPA Voluntary National Guidelines for Management of Onsite and Clustered 

(Decentralized) Wastewater Treatment Systems (USEPA, 2003), which recommends 

management measures for on-site systems based on the administrative and managerial capacity 

of management entities, the complexity of technologies used, and the value and proximity of 

6-5 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

resources to be protected. The guidance contains tools and directions to assist states and 

communities in developing management programs based on local needs and resources, as well as 

risks to human health and water resources. Activities include planning, design, site evaluation, 

inspections, monitoring, funding, and other functions. The guidelines note the shortcomings of 

on-site programs that: (1) do not have a planning element that considers regional hydrology and 

system densities and discharges; and (2) do not have operation and maintenance requirements 

that ensure monitoring, periodic septic tank pumping, system repair, and upgrades when 

necessary. Many existing OWTS regulatory programs fail to consider the ability of regional soils 

to assimilate pollutants from dozens or hundreds of treatment systems in an area and often leave 

operation and maintenance of these systems to uninformed and untrained homeowners. 

In EPA Voluntary National Guidelines for Management of Onsite and Clustered(Decentralized) 

Wastewater Treatment Systems, EPA recognizes the benefits of both conventional and alternative 

systems and emphasizes the importance of proper planning, site evaluation, system design, 

installation, inspection, operation, monitoring, and maintenance. On-site systems, like sewage 

treatment plants that serve urban areas, require periodic attention and regular servicing to ensure 

that treatment levels meet established performance requirements. Management programs must 

comply with performance requirements by ensuring sludge is pumped from tanks periodically, 

failed or failing systems are detected promptly and repaired or replaced, and undersized or 

underperforming systems are upgraded. 

6.2.2 Management Measure Selection 

This management measure was selected to ensure that new and existing on-site wastewater 

treatment systems function properly. If these systems fail, wastewater can pool on ground 

surfaces or migrate to aquifers or surface waters and cause significant public health or 

environmental problems (e.g., disease outbreaks, eutrophication, loss of dissolved oxygen). This 

management measure supports a performance-based approach to system management and is 

consistent with the EPA Voluntary National Guidelines for Management of Onsite and Clustered 

(Decentralized) Wastewater Treatment Systems (USEPA, 2003) and the Onsite Wastewater 

Treatment System Manual (USEPA, 2002a). 

6.3 Management Practices 

6.3.1 Permitting and Installation Programs 

EPA believes that on-site system permitting and installation programs that protect surface and 

ground waters are necessary to decrease or eliminate risks to human health and sensitive 

ecological resources. Approaches that match the treatment capabilities of various on-site 

technologies to the conditions and sensitivity of the receiving environment (ground water or 

surface water) are preferred. EPA recognizes that, due to a lack of staff expertise, funding, 

assessment data, regulatory infrastructure, public support, and other resources, not all on-site 

regulatory agencies or management programs will have the ability to implement performancebased approaches. 

6-6 
Management Measure 6: New and Existing On-Site Wastewater Treatment Systems 

Therefore, alternative approaches, which include prescriptive standards that provide appropriate 

levels of protection for human health and water resources, are included among the acceptable 

management practices summarized in this section. These standards include prescribed treatment 

technologies, minimum requirements (e.g., soils, slopes) for proposed installation sites, 

mandatory setback and separation distances, and specific system component requirements (e.g., 

septic tank screens, grease traps). They will be considered acceptable management practices if 

they provide reasonable assurances of protecting public health and water resources when applied 

under the specific site conditions. 

Elements supporting this Management Practice are listed below and correspond with the 

management measures listed in Section 6.1. 

6.3.1.1 Planning activities 

Comprehensive planning can provide valuable information and support for on-site system 

placement and management. Integrating planning with regulatory programs can provide a basis 

for ensuring the performance of existing systems and permitting future installations. Planning 

involves the examination of many variables: 

− A wide range of environmental characteristics (e.g., ground water, topography, soils, 

climate, sensitive ecological resources); 

− The locations and types of facilities that could be part of an overall wastewater 

management plan; 

− The organizational and institutional structures that exist or may need to be created; and 

− Financial support for their development and implementation. 

At a minimum, planning should identify areas where: 

− Installation of conventional systems can be allowed at specified densities; 

− Alternative systems could be required; and 

− On-site systems could be permitted only under strict design and performance 

requirements and assurances for long-term monitoring and maintenance. 

6.3.1.1.1 Comprehensive planning 

Comprehensive planning provides one of the best vehicles for ensuring that on-site management 

issues are considered under future growth and development scenarios. Comprehensive planning 

and zoning are closely related and are usually integrated. Comprehensive planning sets overall 

guidance and policies; zoning provides the detailed regulatory framework for implementation. 

Comprehensive planning that addresses environmental protection while providing adequate 

public services such as wastewater treatment can be administered through zoning regulations 

that: 

6-7 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

— Specify prescriptive or performance requirements for individual or clustered systems 

installed in unsewered areas, preferably by watershed, subwatershed, or ground water 

recharge area; 

— Limit, manage, or prevent development on sensitive natural resource lands or in 

designated critical areas (e.g., in wellhead protection zones or shellfish habitat runoff 

catchments, or near nutrient-sensitive waters and wetlands); 

— Encourage development within urban growth areas serviced by sewer systems, if 

adequate capacity exists; and 

— Consider factors such as system densities, hydraulic and pollutant output, proximity to 

water bodies, soil and hydrogeological conditions, water quality, and cumulative loadings 

from all systems, including future systems, in planning and zoning decisions. Large 

numbers of soil-based on-site systems discharging to a confined area (e.g., high-density 

subdivisions) can overwhelm the capacity of soils to assimilate and treat wastewater 

pollutants of concern, such as nutrients and pathogens. 

It should be noted, however, that it is not necessary for the on-site regulatory agency or 

management entity to oversee or administer the planning program. In many areas, local or 

regional planning offices collect and store the types of information needed for on-site system 

management. Some of these offices have the ability to generate geographic information system 

(GIS) maps that can incorporate water resource, soil, topographic, and other information that 

provides screening-level site criteria for proposed installation of on-site systems. Coordination 

with planning offices to designate ecologically sensitive areas and those approved for future onsite system installations can significantly improve the management capabilities of the on-site 

regulatory agency or management program and improve watershed protection. 

6.3.1.1.2 Wastewater treatment continuum concept 

Decision-makers responsible for approving wastewater collection and treatment services for 

existing or new facilities often require information and guidance on the various options available. 

Protection of public health and valued water resources and cost are the primary decision-making 

criteria in most cases. Both centralized sewer service and decentralized/on-site systems protect 

public health and water resources, though treatment levels and cost may vary depending on 

technology, operational factors, system maintenance, and site-specific conditions (e.g., combined 

sewer overflows, bypasses, and nutrient removal requirements for centralized systems; and 

geology, soils, climate, and other factors for decentralized/on-site systems). 

A number of wastewater treatment and collection options exist along the continuum between 

individual on-site systems and centralized sewer service. The following options are suggested for 

decision-makers seeking to improve collection and treatment in existing areas or to provide these 

services to new development (Venhuizen, 2000): 

— Current practice, employing conventional septic tank/soil absorption field systems within 

the confines of each residential or facility lot; 

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Management Measure 6: New and Existing On-Site Wastewater Treatment Systems 

— Alternative on-site systems for each lot. Examples include sand filters, aerobic treatment 

units, vegetated submerged wetlands, and dispersal in shallow, pressure-dosed subsurface 

wastewater infiltration systems; 

— Small-diameter collection/treatment facilities using septic tank effluent drains (STEDs) 

or other shallow, low-cost collection systems to pump or route the flow from each lot to a 

common site for final treatment and dispersal or discharge; or 

— Centralized sewage collection and treatment with the option of either conventional or 

alternative treatment facilities at one centralized plant. 

Each of these strategies should include oversight and management programs to ensure that 

collection and treatment equipment and processes continually meet performance requirements. 

The responsible management entity (RME) should be charged with keeping collection and 

treatment systems working. The RME should have sufficient authority to enforce programmatic 

and other requirements, pay for operational and other costs, and take necessary actions in the 

event of performance failure or emergencies. 

Developing operation, maintenance, and management strategies for decentralized/on-site systems 

in a manner similar to those in existence for centralized systems—or incorporating on-site 

treatment options into the centralized system strategy—can help to ensure that public health and 

water resources are protected effectively and efficiently. 

6.3.1.1.3 Centralized sewage treatment 

As development activity increases the density of OWTS-served housing, commercial 

establishments, and other facilities in a region, it is sometimes cost-effective to extend service 

lines from centralized sewage treatment facilities (i.e., publicly owned treatment works or 

POTW) for wastewater collection and treatment at a central plant. Small towns in the past have 

typically only considered connections to a regional POTW or the construction of a treatment 

facility. Factors to consider other than costs when deciding whether it is beneficial to use 

decentralized/onsite systems, construct a new treatment plant, or extend service lines of a nearby 

system include the following: 

— Age and operational history of existing OWTSs; 

— The RME’s capacity and authority to properly manage OWTSs; 

— Future housing and other development trends based on land use planning information; 

— Proximity and capacity of existing POTW service lines and treatment facilities; 

— Potential for revision to an existing NPDES discharge permit; 

— Suitable financing, land area, and site conditions for construction of POTWs or collection 

lines; and 

— Hydrological impacts and catastrophic risk assessment due to failure of collection 

systems and POTWs. 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

6.3.1.2 System selection, site evaluation, design, and installation 

On-site systems often fail because of improper design and inadequate site evaluation and/or 

installation. Some states require higher levels of treatment near wellhead recharge zones, 

nutrient-sensitive waters, shellfish habitat, or other areas of special concern. On-site wastewater 

treatment systems discharging pathogens that can reach wells or shellfish habitat areas, and those 

that discharge significant inputs of nitrogen or phosphorus to nutrient-sensitive waters, should be 

high-priority candidates for upgrade or replacement (Commonwealth Biomonitoring, 2001). A 

committee advising the Maryland Department of the Environment recommended in 2000 that 

legislation be adopted requiring county water and sewer agencies to designate areas of special 

concern to address elevated nitrogen inputs from existing and new on-site systems (Maryland 

Department of the Environment, 2000). State income tax credits of up to $1,100 per year for 

three years were suggested to assist homeowners with increased system costs. Existing systems 

would only require nitrate removal in these areas when system replacement was required. 

6.3.1.2.1 Performance-based programs 

Performance requirements for individual or clustered on-site treatment systems are most often 

based on assurances that system discharges will not cause violations of surface water quality 

standards or drinking water standards. A performance-based program includes the following 

components: 

— Performance goals; 

— Performance criteria; 

— Performance requirements; and 

— Performance monitoring. 

(a) Performance goals. Performance goals define the larger issues that are important to consider 

in on-site system siting, selection, design, and management. A properly functioning on-site 

system should be able to meet two basic performance goals: protect public health and protect 

water resources. 

An example of a performance goal might be to protect the surface water from nutrient 

enrichment in environmentally sensitive areas such as lakes or estuaries. Detailed planning, 

design, installation, and management programs can help prevent placement of inappropriate 

systems in areas with unsuitable soils, on sites adjacent to valued and sensitive surface water 

bodies, and at densities that exceed regional hydrologic and pollutant assimilative capacities. 

Such an approach can help control or minimize pollutant loadings and associated impacts on 

surface and ground waters. 

The Code of Massachusetts Regulations allows a state tax credit of up to 40 percent of the cost of a 

new on-site system or system repairs. The credit is capped at $1,500 per year and $6,000 total and is 

limited to homeowners living in the residence served by the repaired or replaced on-site system (Code 

of Massachusetts Regulations, 2001). 

Promoting System Upgrades Through Innovative Financing

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Management Measure 6: New and Existing On-Site Wastewater Treatment Systems 

(b) Performance criteria. Performance criteria are measurable indicators that identify the 

pollutants of concern for a particular area so that benchmarks or performance requirements 

can be established to reduce further inputs of those pollutants. Performance criteria are used 

to quantify progress in achieving performance requirements for specific pollutants. Some 

examples of site-scale performance criteria include effluent concentration limits for nitrate, 

biochemical oxygen demand (BOD), fecal coliform bacteria, and overall flow. Watershedscale criteria might include total hydraulic input to a ground water recharge zone from on-site 

systems, and total nitrogen load or total phosphorus load to ground water or surface waters. 

(c) Performance requirements. Performance requirements are criteria-based limits that define 

acceptable environmental impacts and public health risks associated with on-site systems. 

Performance requirements are based on the type of water body that ultimately receives 

treated wastewater effluent (ground water or surface water) and the present or projected uses 

of that water body (e.g., drinking water source, shellfish habitat, contact recreation). 

Examples of a performance requirement might be that on-site systems in nitrogen-sensitive 

areas must not discharge more than 5 pounds of nitrogen per year, or that nitrate 

concentrations in OWTS effluent cannot be greater than 15–20 milligrams per liter (mg/L). 

Resource protection performance requirements are based on the assumption that any given 

resource has a threshold (carrying or assimilative capacity) beyond which it cannot function 

and may deteriorate. Nitrogen requirements are more likely to be appropriate near marine 

waters because this nutrient is usually the limiting factor for algal growth in coastal areas. In 

ground waters, nitrogen can degrade drinking water resources as well. The Commonwealth 

of Massachusetts has designated certain areas, such as wellhead protection areas, areas in 

public water supply watersheds, and nitrogen-sensitive coastal embayments or other 

nitrogen-sensitive water bodies, as “Nitrogen-Sensitive Areas” (Code of Massachusetts 

Regulations, 1995) and has issued requirements to ensure their protection. Environmentally 

sensitive areas might include nitrogen-limited coastal waters, phosphorus-limited inland 

waters, shellfish habitat, and ground water used as drinking water. Typical performance 

criteria and examples of corresponding performance requirements are listed below: 

— Fecal coliform bacteria as an indicator of the possible presence of pathogens (e.g., 

less than 200 colony-forming units per 100 milliliters [cfu/100 ml]) for support of 

primary contact recreation or 14 cfu/100 ml in shellfish waters 

— Nitrogen in the form of nitrate in potable ground water (e.g., less than 10 mg/L) and 

as total nitrogen in nitrogen-limited coastal waters to prevent or reduce enrichment 

— Phosphorus concentration in surface waters where phosphorus is the limiting element 

for algal growth (e.g., less than 0.025 mg/L to support warm water aquatic habitat) 

— BOD for surface waters requiring high levels of dissolved oxygen for propagation of 

fish and shellfish (e.g., 5–10 parts per million of 5-day BOD after tertiary treatment to 

support warm water aquatic habitat) 

— Nuisance factors (e.g., no objectionable odors emanating from the septic tank or 

infiltration field area, no sewage surfacing to minimize risk of human contact) 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

(d) Performance monitoring. Performance monitoring tracks progress in achieving performance 

requirements. Typical approaches involve measuring or assessing performance criteria at 

some specified point of compliance (e.g., a designated performance boundary). For example, 

if waters of a commercial shellfish habitat in a coastal bay are experiencing elevated bacterial 

contamination, a fecal coliform bacteria performance requirement for on-site systems in the 

area might be established at the property line or shoreline of the lot. A variety of monitoring 

programs have been developed to assess the performance of on-site systems. Approaches 

include measurement of chemical parameters (e.g., nitrogen, phosphorus, BOD, nitrate) in 

effluent or receiving waters; analysis of fecal coliform/fecal streptococcus ratios; and a 

variety of new, experimental, analytical approaches using molecular, chemical, or 

biochemical methods (e.g., ribotyping, antibiotic resistance analysis, randomly amplified 

polymorphic DNA, pulse field gel electrophoresis, caffeine tracking) (Hagedorn, 2000). 

Validation and cost issues prevent widespread use of the newer methodologies at the present 

time, but research in the field shows significant promise. 

The Critical Point Monitoring (CPM) approach being developed in Washington State 

provides a systematic approach to choosing critical locations to monitor specific water 

quality parameters (Eliasson et al., 2001). The program is most suitable for responsible 

management entities operating comprehensive management programs. CPM provides an 

appropriate framework for monitoring treatment train components (i.e., septic tank, 

infiltration field, sand/media filters, aerobic treatment units), though it should be recognized 

that evaluations of overall system effectiveness—and compliance with performance 

requirements—should be based on monitoring at designated performance boundaries. 

Tracer dye tests, analysis of E. coli concentrations in receiving waters, and system 

inspections are the most widely used methods for monitoring on-site system performance at 

present. The first only provides indirect hydrologic information, while the latter two offer 

direct utility to assess whether performance goals are being achieved. For the purpose of 

watershed-scale monitoring and modeling, the use of output criteria derived from typical 

performance ranges of on-site system types used in the area is a common practice. Models 

can be useful tools to predict potential ground water impacts if they are based on site- or 

regional-specific characteristics and are calibrated to achieve the best estimates of actual field 

results. They are rarely accurate under all conditions, however, and must be supplemented 

with actual field monitoring results when available. 

6.3.1.2.2 Modeling system performance and impacts 

There have been relatively few attempts at developing modeling tools to predict and simulate 

nutrient fate and transport mechanisms from on-site system effluent (Tetra Tech, 2000; Bicki and 

Brown, 1991; Harmesen et al., 1991). Most of the work has focused on identifying nitrate 

loading to ground water for the purpose of planning for drinking water protection. Computer 

models require a considerable amount of site-specific information regarding wastewater 

characteristics, discharge volumes, soils, topography, underlying geology, ground water, and 

climate, but they can be useful tools for assessing the long-term impacts of OWTSs in an area 

and developing strategies to mitigate potential problems. 

The State of Florida developed a computerized model to assess ground water contamination 

potential in selected hydrogeologic regions as a tool to guide development of subdivision 

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Management Measure 6: New and Existing On-Site Wastewater Treatment Systems 

regulations (Florida HRS, 1993). The model incorporated features of the state’s varied surficial 

hydrology and soil regimes and provided estimations of the transport and fate of nitrogen 

compounds. The Florida model uses a steady-state, one-dimensional flow field with threedimensional dispersion and assumes retardation and first-order decay rates to be zero. Nitrate 

contaminant plumes generated by the model show a variety of dispersion and transport scenarios 

and confirm that increasing lot size from four homes per acre to two homes per acre (and even 

fewer in areas of high porosity) reduce nitrate concentration and migration in ground water by 

approximately 50 percent (from 10 mg/L to 5 mg/L 700 feet downgradient of the subdivision 

under study). The results suggest that concerns over nitrate contamination of ground waters from 

large, densely developed subdivisions with OWTSs are not unfounded. They support 

recommendations to monitor ground water nitrate concentrations below and downgradient of 

large subdivisions with home densities greater than four units per acre. 

Another model developed for the Indian River Lagoon National Estuary Program found that 

nitrogen inputs linked to on-site systems constituted 12 percent of the total nitrogen load into the 

lagoon, an amount nearly equal to the load from cattle. The loading model provides a mechanism 

for calculating total nitrogen inputs into the aquatic system, and it attempts to predict the 

nitrogen concentrations in ground water based on hydrological parameters (University of 

Massachusetts, 2000). Efforts to calibrate the ground water prediction capabilities of the model 

are ongoing. 

6.3.1.2.3 Applying system siting criteria 

Conventional and many alternative on-site systems include a SWIS, which requires a certain 

minimum area of soil, sand, or other treatment media to effectively remove pathogens and other 

pollutants. Under a prescriptive approach, setbacks from wells, surface waters, building 

foundations, and property boundaries are minimum requirements necessary to eliminate or 

reduce threats to public health and the environment. Setbacks are used only rarely but can be 

established based on soil type, slope, characteristics of the water table (as defined by the 

implementing agency), sensitivity of aquatic resources, and type of on-site system. Under a 

prescriptive program, setback guidelines also should be established for both conventional and 

alternative on-site systems. Recommendations for horizontal separation distances are based on 

the degree of pre-soil application treatment achieved, as well as site-specific factors such as 

climate, topography, soil permeability, ground water gradient, ground water flow, and geology. 

The management entity should adopt measures that restrict the placement of wastewater 

treatment systems in inappropriate soils, in proximity to valuable surface waters, and at densities 

too high for soils to treat pollutants sufficiently. One example is the lack of available 

concentrations of certain metals that retard phosphorus movement to nearby surface waters. 

Separation and setbacks can also be used under the performance-based approach. Under this 

approach, setback or separation distances should be based upon research or field data that 

demonstrate pollutant removals needed to meet performance requirements given the specific site 

conditions and treatment technology applied. Pretreatment systems that discharge effluent 

containing concentrations of bacteria, nitrogen, and phosphorus below requirements established 

to protect water quality can be sited closer to water resources if impact analyses determine that 

contamination risk is unlikely. 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

6.3.1.2.4 Site evaluations that assess suitability for specific technologies 

States vary greatly in their approach to evaluating site suitability; such approaches range from no 

specific requirements to very detailed evaluations that require qualified soil scientists and 

hydrogeologists (NSFC, 1995). A performance-based approach to site evaluation may involve 

one or more of three evaluation approaches: 

1. Soil-based. Sites are characterized by conducting a soil profile analysis, usually through 

the use of soil maps, field data, and inspection of the soil profile in a backhoe pit. Many 

states now require a soil profile analysis to determine site suitability for conventional 

systems. 

The soil-based approach focuses on site-specific observation of soil properties that 

significantly affect the performance of soil-based on-site systems. The soil-based 

approach has two major advantages: (1) direct observation of soil properties provides a 

considerable amount of quantitative and qualitative information that can be used to select 

or modify on-site system design; and (2) site evaluations for individual systems can 

sometimes be completed in a single visit. The major disadvantage of this approach is that 

it provides little quantitative information on hydrologic properties and characteristics of 

the region and sub-watershed. The risk of inadequate hydrogeologic characterization 

increases when on-site system densities increase. 

Soil assessments are best conducted by observing the soil profile on the wall of a backhoe 

pit that is 48 to 72 inches deep. Soil layers should be characterized to a depth of at least 3 

to 5 feet below the proposed excavation of the effluent absorption field, especially in 

highly porous soils. Characterizing the soil profile in a backhoe pit is best accomplished 

using natural lighting because soil texture, structure, color, mottling, and iron or 

manganese concretions can be observed, assessed, and described more accurately. Hand 

augers tend to disturb and compress the soil and disguise soil layers, making it difficult to 

observe structure and other features. Pits should be excavated at the perimeter of the soil 

absorption field rather than in the middle of it because settling might cause problems with 

distribution piping and absorption trench stability, and the disturbance could modify 

subsequent soil system performance. 

2. Hydrogeologic-based. Surface water and ground water hydrology and the geology of the 

management area are characterized to determine treatment technology selection and 

maximum system densities. Zones can be created to establish minimum lot sizes, 

maximum discharge rates per acre, or minimum treatment efficiencies (e.g., effluent 

nitrogen concentrations). Percolation rate tests, which have been used extensively in the 

past to characterize wastewater dispersion in the soil, do not predict treatment 

effectiveness or ensure future hydraulic performance. 

Hydrogeologic-based evaluations originated with the development of the percolation test 

in the 1920s. Although the percolation test is simple to conduct and can provide some 

information on relative infiltration rates, it does not necessarily provide design 

information because of its inability to discern what controls the rate of water loss from 

the hole. Also, the test cannot accurately predict infiltration rates at equilibrium operation 

or in downgradient zones through which the effluent will migrate. 

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Management Measure 6: New and Existing On-Site Wastewater Treatment Systems 

Hydrogeologic characterization can also include testing for hydraulic conductivity, 

porosity, and permeability, usually requiring multiple extended site visits. Cluster and 

small community on-site systems (> 2000 gpd) require more extensive hydrogeologic 

characterization. Multifactor approaches for site evaluation use information regarding 

soils, hydrogeology, mineralogy, cation exchange, and possibly other information such as 

regional effluent loading models. 

3. Multifactor-based. A variety of factors (e.g., soils, climate, ground water conditions, 

slopes, OWTS densities, proximity to and status of water resources) in the management 

area are characterized to establish zones reflecting likely treatment effectiveness and the 

potential for public health and environmental impacts. Conventional systems are 

permitted in nonsensitive zones that meet minimum soil, separation/setback, and other 

prescriptive requirements. Alternative systems should be required for sensitive sites that 

cannot support conventional SWIS-based applications. Sites within sensitive zones can 

be required to meet performance standards and to be closely managed for continued 

compliance. 

Regardless of approach, the objective of the site investigation is to evaluate the wastewater 

treatment and dispersal capabilities of the site and surrounding area. The site evaluation 

systematically gathers information that is used to narrow the range of OWTS design options to 

the one that best accomplishes the overall performance goals of protecting human health and the 

environment. The evaluation should begin with a consideration of both regional hydrology and 

the density and discharge of existing OWTSs in the area. Regional planning programs, where 

they exist, can provide a significant amount of information during this stage of the process. Other 

reconnaissance activities prior to the actual site visit should include researching the following: 

soil surveys; geology, topography, and surface water and ground water resources; OWTS 

installations in the vicinity and their operating record; well locations and hydrogeological records 

in the area; and maps showing utility lines and other features that might have an impact on 

design and placement of the system. 

Landscape position, location of treatment unit components, slopes, trees, and other features (e.g., 

drainages, fences, pipelines, electric lines) should be noted on a site plan that is filed with permit 

documents. The soil analysis should include identification of the major horizons and their 

structure, texture, color, mottles and concretions, as well as other notable features (e.g., rocks, 

organic matter, wetness). If percolation tests are used, they should be conducted in strict 

accordance with established procedures and should always be accompanied by a detailed 

investigation of the soil profile and regional conditions. Permitting of OWTSs on the basis of 

percolation tests alone is not recommended. 

Table 6.3 presents a list of site features that might require evaluation prior to selecting the system 

design and installation site. The site evaluation process typically differs for individual OWTSs 

and larger-scale cluster or small community systems; i.e., data on every feature on the checklist 

does not have to be collected for every individual home site. Site assessments should be 

performed to determine the soil infiltration rate, expected soil pollutant removal capacity, 

acceptable hydraulic loading rate, and required depth to the water table, at a minimum, prior to 

design and application for a construction permit for on-site systems. A simple individual home 

site evaluation can be accomplished in a single site visit when a soil-based approach is used. 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Three American Society for Testing and Materials (ASTM) practices covering surface 

characterization (ASTM, 1995), subsurface soil characterization (ASTM, 1996b), and 

preliminary sizing and delineation of subsurface soil absorption or constructed filter field areas 

(ASTM, 1996a) give specific guidance on how this can be accomplished (http://www.astm.org/). 

Surface and some subsurface characterization practices are shown in Table 6.4. The ASTM 

standard practice for characterizing subsurface conditions through test pit inspection is 

summarized in Table 6.5. These practices can be specified when hiring contractors and 

consultants. 

Table 6.3: Site features that should be evaluated before OWTS design and installation. 

Type Site Feature 

Surface Features Location of property boundaries, location of existing and/or proposed structures, location of 

surface water features (landscape position and land form, including intermittent and perennial 

drainage ways, irrigation ditches, streams, swales, depressions, water bodies, and wetlands), 

topography (use local regulatory suitability criteria or Natural Resources Conservation 

Service [NRCS] soil survey classes), location of water supply sources (well, public water 

supply reservoir), location of buried anthropogenic features (water lines, utility lines, etc.), 

location of disturbed soil (cut and fill), other significant features (large trees, bedrock at the 

surface, etc.) 

Soil Features Major soil horizons, texture and structure of each horizon, color, mottles, other relevant 

features of each horizon (rupture resistance, penetration resistance, wetness, pore 

characteristics, presence of roots), depth to bedrock, depth to low permeability (i.e., 

restrictive) soil horizons (fragipan, caliche, duripan, etc.), depth and thickness of strong 

textural contrasts. Phosphorus (P) Index when P retention is needed. 

Hydrogeologic 

Features 

Depth to seasonal high water table and shallow ground water tables, potentiometric surface, 

ground water flow direction and gradient, percolation test results, saturated hydraulic 

conductivity (estimated, field, and laboratory), ground water time of travel to points of 

interest, unsaturated hydraulic conductivity relationships, other water budget parameters 

(precipitation, potential evapotranspiration, etc.)

Table 6.4: Practices to characterize surface and subsurface features of proposed OWTS 

sites (ASTM, 1995, 1996b). 

Description of activity Information from research 

Preliminary Documentation — Site survey map 

— Soil survey, U.S. Geological Survey (USGS) 

topographic map 

— Aerial photos, wetland maps 

— Natural resource inventories 

— Applicable regulations and/or setbacks 

— Hydraulic loading rates 

— Criteria for alternative OWTSs 

— Size of house or facility 

— Loading rates, discharge types 

— Planned location of water well 

Scheduling — Planned construction schedule 

— Date and time for meeting 

Description of Activity — Information from field study 

Identification of Unsuitable Areas — Water supply separation distances 

— Regulatory buffer zones and setbacks 

— Limiting physiographic features 

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Management Measure 6: New and Existing On-Site Wastewater Treatment Systems 

Table 6.4 (continued). 

Description of activity Information from research 

Subsurface Investigations — Ground water depth from pit or auger 

— Soil profile from backhoe pit 

— Percolation tests 

Identification of Recommended OWTS Site — Integration of all collected data 

— Identification of preferred areas 

— Assessment of gravity-based flow 

— Final selection of OWTS site 

Table 6.5: Practices to characterize subsurface conditions through test pit inspection 

(ASTM, 1996a). 

Description of activity Process steps Information to be collected 

Select backhoe pit site(s) near 

but not in proposed drainfield 

Orient pit so that sunlight illuminates 

vertical face of pit 

Proposed location of soil absorption 

field 

Excavate pit to depth required 

by regulations 

Pit excavation Required ground water separation 

distance, soil profile depth 

Enter test pit — Take safety precautions 

— Beware of cave-ins 

— Select area of pit wall to 

examine 

Safe depths for unbraced pit walls 

Expose natural soil structure Use soil knife, blade, screwdriver, or 

other tool to pick at area 0.5 m wide 

along full height of pit wall 

Soil structural type (e.g., prismatic, 

columnar, angular blocky, subangular 

blocky, platy, granular) 

Describe soil horizons — Note master soil horizon layers 

— Describe features of each 

horizon 

List soil horizon features: 

— Depth of horizon and thickness 

— Moisture content 

— Color (i.e., hue, value, chroma) 

— Volumetric percentage of rock 

— Size, shape, type of rock found 

— Texture of <2mm fraction of 

horizon 

— Presence or absence of mottles 

and other redoximorphic 

features 

— Soil structure by grade 

— Level of cementation 

— Presence or absence of 

carbonates 

— Soil penetration resistance 

— Abundance, size, and 

distribution of roots 

Determine lateral changes in 

soil profile 

Use hand auger and/or compare to 

profile of second pit 

Determine changes, if any, in soil 

profile across proposed site 

Interpret results Identify limiting depths — Check vertical separation 

distances 

— Identify mottled layers and 

concretions 

— Determine depth to saturation 

— Measure depth to confining layer

Issue site report Log all data onto survey form Develop system type, site location, 

and installation recommendations

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Several systems have been developed to perform source water vulnerability assessments and to 

map locations where site conditions might preclude the use of conventional on-site systems. A 

system such as the DRASTIC methodology (Aller et al., 1987) can be used to map areas where 

aquifers might be vulnerable to pollution from on-site systems. DRASTIC considers soil 

permeability, depth to ground water, and aquifer characteristics. Florida adapted the DRASTIC 

approach to produce digital maps showing potential areas where ground water threats might 

increase (http://www.dep.state.fl.us/gis/datadir.asp). The U.S. Department of Agriculture 

(USDA) developed soil maps that contain detailed information on regional soils, including 

suitability for conventional on-site systems, and is updating these maps in some areas. The 

USDA National Soils Survey Center (http://ssldata.nrcs.usda.gov/) provides county-level soil 

information nationwide. 

States are implementing GIS-based programs for identifying and mapping critical water supplies 

and aquifer protection areas. Some states have established zones that define effluent quantity and 

quality and system options available to meet those requirements. Computer simulation models 

have also been developed that assess the impact from locating on-site systems at various 

densities within a watershed. For example, the Buzzards Bay Project of the National Estuary 

Program provides an online nitrogen input modeling spreadsheet that can be adapted for local 

use by entering appropriate information for land use, nitrogen loading rates, watershed size, 

projected build-out, and other parameters 

(http://www.buzzardsbay.org/nitrmang/bbploadcalc.xls). 

6.3.1.3 Education, training, licensing, and/or certification programs 

In the past, a few states established training programs for site evaluators and adopted morestringent codes for system design, setback distances, and general site requirements 

(Kreissl, 1982). If a site were declared unsuitable by these evaluators under the code 

prescriptions, some of these states would allow professional engineers to propose system designs 

that could overcome site limitations. Many jurisdictions (regulatory agencies) have begun to 

favor employing trained, experienced, professional staff who can make judgments and decisions 

on system design and siting in an efficient, effective manner. This practice must be differentiated 

from programs that use compliance enforcement staff to design systems. Such approaches are not 

recommended due to potential conflicts of interest resulting from design and compliance 

determinations by the same entity. 

 Most states have minimum requirements (e.g., college coursework, state-sponsored training) for 

oversight agency staff (e.g., health department permitting personnel), but some states have more 

stringent competency requirements. 

In many states, system installers must be certified (see Table 6.6). Florida requires installers to 

meet certain minimum requirements, demonstrate experience, provide references, pass an 

examination, and complete six hours of approved classroom instruction annually to retain their 

certification. Minnesota has had a certification program for installers, designers, pumpers, and 

inspectors since the early 1970s; the program became mandatory for all service providers in 

1994. Maine instituted a licensing program for site evaluators in 1974 and saw system failure 

rates drop to insignificant levels (Kreissl, 1982). Site evaluators in Maine must now be licensed 

professional geologists, soil scientists, or engineers with at least one year of relevant field 

6-18 
Management Measure 6: New and Existing On-Site Wastewater Treatment Systems 

experience. They must also pass a written examination and a field practices test (Maine 

Department of Health Services, 1996). 

Requirements for site evaluators, system designers, installers, inspectors, and maintenance 

service providers vary widely among the states. Some states have few, if any, requirements for 

service personnel, whereas other states require professional certification and ongoing training for 

most service providers (see Table 6.6). In addition, some states issue permits or grant exemptions 

that allow homeowners to design and install on-site treatment systems at their primary residence. 

Table 6.6: Survey of state certification and licensing programs for onsite wastewater 

service providers (Noah, 2000). 

State Contractors Installers Inspectors Pumpers Designers Engineers Geologists Operators

AL Y Y Y Y N Y Y Y 

AK Y Y NA NA NA Y NA NA 

AZ Y Y NA Y NA Y Y NA 

AR N Y N Y Y N N N 

CA N N N N N N N N 

CO N N N N N Y N Y 

CT NA Y Y Y NA Y NA NA 

DE Y Y N Y Y Y N Y 

FL Y Y Y Y Y Y Y Y 

GA Y Y Y Y N N N N 

HI N N N N N Y N Y 

ID N Y Y Y N N N N 

IL Y Y NA Y NA NA NA NA 

IN N N N N N N N N 

IA N N N Y N N N N 

KS NA NA NA NA NA Y Y Y 

KY Y Y Y Y N N N N 

LA NA Y NA NA NA NA NA NA 

ME N Y Y N Y Y Y N 

MD N Y Y N N N N N 

MA Y Y Y Y Y Y N Y 

MI N N N N N N N N 

MN NA Y Y Y Y NA NA Y 

MS NA Y Y Y NA NA NA NA 

MO Y N N Y N Y N N 

MT N N N N N N N N 

NE N N N N N N N N 

NV NA NA NA NA NA NA NA NA 

NH N Y N N Y Y N Y 

NJ N N N N N N N N 

NM Y Y N N N N N N 

NY N N N Y N N N N 

NC N N Y N N N N Y 

ND Y Y Y N N N N N 

OH N N N N N N N N 

OK Y Y N Y Y N N Y 

OR Y Y Y Y Y Y Y Y 

PA N N Y N N Y Y N 

RI Y Y Y N Y Y N Y 

6-19 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Table 6.6 (continued). 

State Contractors Installers Inspectors Pumpers Designers Engineers Geologists Operators

SC Y Y NA Y NA NA NA NA 

SD N Y N N N N N N 

TN N Y N Y N Y Y Y 

TY N Y Y Y N N N Y 

UT N N N N N N N N 

VT N N N N Y N N Y 

VA N N N N N Y Y Y 

WA N N Y N Y N N N 

WV N N N Y N N N N 

WI N Y Y Y Y Y Y N 

WY N N N N Y Y Y N

Y = yes; N = no; NA = not available. 

NSF Onsite Wastewater Inspector Accreditation Program

NSF International has developed an accreditation program to verify the proficiency of persons 

performing inspections on existing on-site wastewater treatment systems (NSF International, 2000). 

The accreditation program includes written and field tests and provides credit for continuing education. 

Inspectors who pass the tests and receive accreditation are listed on the NSF International Web site 

and in the NSF Listing Book, which is circulated among industry, government, and other groups. 

The accreditation process includes four components. A written examination, conducted at designated 

locations around the country, covers a broad range of topics relating to system inspections, including 

equipment, evaluation procedures, trouble-shooting, and the NSF International Certification Policies. 

The field examination includes an evaluation of an existing on-site wastewater treatment system. An 

ethics statement, required as part of the accreditation, includes a pledge by the applicant to maintain a 

high level of honesty and integrity in the performance of evaluation activities. Finally, the continuing 

education component requires requalification every 5 years through retesting or earning requalification 

credits through training or other activities. 

To pass the written examination, applicants must answer correctly at least 75 of the 100 multiple 

choice questions and score at least 70 percent on the field evaluation. A 30-day wait is required for 

retesting if the applicant fails either the written or field examination.

These code provisions, which are linked to outdated farmstead or homestead exemptions, should 

require some demonstration of competency on the part of the prospective homeowner designer or 

installer. For example, Alaska allows homeowners to design and install systems at their 

residence if they complete an approved training course and comply with state design, 

construction, and siting requirements. Approval is granted after the homeowner submits an 

infiltration field size estimate based on a professional analysis (i.e., by an engineer or a 

laboratory) of soils at the proposed site (Alaska Administrative Code, 1999). Another approach 

could include providing technical assistance for system design and close oversight of installation 

to ensure that homeowner-installed systems meet performance requirements. 

On-site programs should establish minimum criteria for all service providers to ensure protection 

of public health and water resources. The Maine program requires that site evaluators be licensed 

and that designers of systems treating more than 2,000 gallons per day or systems with unusual 

wastewater characteristics be registered professional engineers. Prerequisites for applying for a 

6-20 
Management Measure 6: New and Existing On-Site Wastewater Treatment Systems 

license and taking the certification examination are either a degree in engineering, soils, geology, 

or a similar field plus one year of experience, or a high school diploma or equivalent and four 

years of experience (Maine Department of Human Services, 1996). 

Some jurisdictions opt to secure planning, operation, maintenance, and inspection services by 

partnering with other agencies or contracting with private entities to perform these functions. For 

example, the Massachusetts communities of Yarmouth and Dennis contract with an engineering 

firm to conduct system inspections (Shephard, 1996). Many management agencies in highly 

developed areas depend on regional planning or environmental agencies for guidance on the 

hydraulic and pollutant assimilation capacity of water resources in areas proposed for 

development. When on-site management functions are performed by outside entities, it is 

important to establish clear, consistent, and reasonable program requirements, administrative 

processes, and communication procedures. 

6.3.1.4 Inspection of new on-site wastewater treatment systems 

Verifying that systems are constructed and installed as designed helps to ensure that they will 

perform as intended. A construction management program that includes multiple field 

inspections will ensure that system design and specifications are followed during the 

construction process. If a system is not constructed and installed properly, the chances of failure 

increase. For example, if the natural soil structure is not preserved during the installation process 

(i.e., if equipment compacts or smears infiltration field soils) the infiltration field can be 

significantly impaired. Most failures of conventional on-site system soil absorption fields have 

been attributed to hydraulic overloading (USEPA, 1993a). These failures can be exacerbated by 

poor design and installation practices. Effective on-site system management programs ensure 

proper system construction and installation through construction permitting, inspections during 

construction, and designer/installer certification programs. 

Design and plan reviews before construction begins help to acquaint the installer with site 

conditions as characterized by the site evaluator and the proposed system design. During this 

review, details of the construction schedule, inspections, and final permit issuance can be 

discussed and agreed upon. In general, construction should conform to the approved plan and use 

appropriate methods, materials, and equipment. Typical regulatory mechanisms to ensure proper 

installation are reviews of site evaluation procedures and findings, and inspections of systems 

during and after installation. The review and inspection process should include: 

— Preconstruction meeting of the owner, designer, regulator, and contractor; 

— Inspection after delivery of components; 

— Inspections during and after construction (e.g., during excavation and installation of 

components, and after backfilling); and 

— Issuance of a permit to operate the system as designed and built. 

During the construction process, inspections should verify compliance with approved 

construction documents and procedures. If there are not enough management program personnel 

to conduct these inspections, a trained/certified inspector should be assigned to oversee 

6-21 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

installation and certify that it has been conducted and recorded properly. The construction 

process for soil-based systems must be flexible, as construction during wet weather may 

compact, smear, or otherwise alter soil structure. 

6.3.1.5 Installation of conventional or alternative systems 

As noted previously, selection of an on-site system should consider climate, regional hydrology, 

site slopes, soil, ground water characteristics, and the quality requirements of the water(s) 

receiving on-site system effluent. Design, operation, and maintenance information for on-site 

systems can be found in the Design Manual: Onsite Wastewater Treatment and Disposal 

Systems (USEPA, 1980), the Onsite Wastewater Treatment System Manual (USEPA, 2002a) and 

the Draft Onsite Wastewater System Management Handbook (USEPA, 2002b). Table 6.7 

summarizes the different treatment technologies used to remove various pollutants of concern. 

A conventional on-site system consists of a septic tank, as shown in Figure 6.2, and a SWIS. 

Septic tanks perform the following four important functions: 

1. Removal of settleable and floatable solids, oils, and grease from raw wastewater; 

2. Storage of the removed solids; 

Figure 6.2: Septic tank detail (University of Missouri Extension Service, 1997). 

6” to 12” 

soil or 

locking 

cover

Length = 2 to 3 times width

D = Liquid depth (0.2 D = 20% of total liquid depth)

Liquid 

level

0.2 D

0.4 D

0.2 D

1” min.

6” min.

0.2 D max.

0.6 D

36” D 

min.

Inlet Outlet

3” min.

6” diameter 

inspection 

pipe

20” or larger 

manhole 6” diameter 

inspection 

pipe Cap

6” to 12” 

soil or 

locking 

cover

20” or larger 

manhole 6” diameter 

inspection 

pipe

6” diameter 

inspection 

pipe Cap

1” min.

Liquid 

level

0.2 D

0.4 D

0.2 D

Length = 2 to 3 times width

D = Liquid depth (0.2 D = 20% of total liquid depth)

6” min.

0.2 D max.

Inlet Outlet

3” min.

0.6 D

36” D 

min.

6-22 
Management Measure 6: New and Existing On-Site Wastewater Treatment Systems 

3. Partial anaerobic digestion (liquefaction) of settled organic matter; and 

4. Flow attenuation. 

Table 6.7: Treatment technologies for OWTSs. 

Treatment objective Treatment process Treatment methods 

Sedimentation Septic tank 

Free water surface constructed wetland 

Vegetated submerged bed 

Lagoons 

Septic tank effluent screens 

Suspended solids 

removal 

Filtration Packed bed media filtersa

Mechanical disc filters 

Soil infiltration 

Activated sludge Extended aeration 

Fixed film activated sludge 

Sequencing batch reactors 

Fixed film aerobic bio-reactor Soil infiltration 

Packed bed media filtersa

Trickling filter 

Fixed film activated sludge 

Rotating biological contactors 

Soluble carbonaceous 

BOD and ammonia 

removal 

Lagoons/wetlands Free water surface constructed wetland 

Biological nitrification/ 

denitrification 

Activated sludge (nitrification only) 

Sequencing batch reactor (only if designed with 

certain operating modes) 

Fixed film bio-reactor (nitrification only) 

Recirculating media filter 

Fixed film activated sludge (nitrification only) 

Anaerobic upflow filter (denitrification only) 

Anaerobic submerged media reactor (denitrification) 

Submerged vegetated bed (denitrification) 

Free water surface constructed wetland 

Nitrogen removal 

Ion exchange Cation exchange (ammonium) 

Anion exchange (nitrate) 

Phosphorus removal Adsorption Soil infiltration 

Iron-rich packed bed media filter 

Sequencing batch reactor (only if designed with 

certain operating modes) 

Filtration/predation/inactivation Soil infiltration 

Packed bed media filtersa

Pathogen removal 

(bacteria, viruses, and 

parasites) Disinfection Hypochlorite feed 

Ultraviolet light 

Flotation/adsorption Grease trap 

Septic tank 

Mechanical skimmer 

Grease removal 

Aerobic biological treatmentb All types a Including dosed systems; granular [sand, gravel, glass], peat, textile, foam. 

b Incidental removal will occur, although overloading is possible.

Removal of total suspended solids (TSS) is usually 70 to 85 percent for well-designed septic 

tanks. Other pollutant removal rates are affected by the characteristics of the wastewater. 

Typically, reduction of BOD is 40 to 60 percent. Nitrogen and phosphorus removals are 

approximately 10 to 20 percent, while fecal coliforms are reduced by approximately 1 log 

(USEPA 2002a). The conventional system accepts both graywater (wastewater from showers, 

6-23 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

sinks, and laundry) and blackwater (wastewater from toilets). Depending on climate, diet, and 

other factors, the tank will need to be pumped every 3 to 5 years, since the pumping interval 

depends on the rate of accumulation of sludge, oils, and grease. Periodic visual inspection or 

remote sensing of the depth of those accumulations is possibly the most efficient way to 

determine pumping intervals. 

A gravity-flow SWIS is the most commonly used treatment and discharge method for OWTS 

septic tank effluent. Soil absorption systems usually consist of covered excavations filled with 

porous media and perforated pipes or plastic leaching chambers with a distribution system for 

introducing and dispersing wastewater throughout. SWISs work well at sites with moderately 

permeable soils and sufficient vertical depth to ground water (i.e., the seasonally high water 

table), bedrock, or other limiting layer. The most common types of hydraulic failure of these 

systems are clogging of the infiltrative surface, insufficient separation distance to the water table, 

insufficient percolation capacity of the soil, and hydraulic overloading. Trenches and leaching 

chambers are the most widely used designs for both individual residences and commercial 

establishments. Uniform distribution and dosing via siphons or pressurized distribution are the 

best methods of pollutant removal because they distribute the wastewater load widely and 

uniformly across a large surface and sidewall area. 

6.3.1.5.1 Pollutant removal processes for conventional systems 

Nitrogen in domestic wastewater can be removed through effective linking of aerobic and 

anaerobic biochemical transformation processes, but in general, most conventional septic 

systems are not considered effective in removing nitrogen without additional treatment in the 

soil. Septic tanks remove approximately 30 percent of the nitrogen in raw domestic wastewater 

(University of Wisconsin, 1978). Percolation through 3 to 5 feet of soil can remove 0 to 20 

percent of the total nitrogen in septic tank effluent (Siegrist, 2001). Additional nitrogen removal 

is possible under optimum soil and denitrification (e.g., anaerobic and carbon-rich) conditions. 

Factors that favor denitrification in soil absorption fields include fine-grained soils such as silts 

and clays, layered soils that feature alternating fine-grained and coarse-grained layers, and 

organic matter or sulfur compounds in the infiltrative medium. Placing the soil absorption field 

high in the soil profile where organic matter is more likely to exist, and dosing effluent to 

achieve alternating wet/dry (anaerobic/aerobic) cycles, can aid denitrification and reduce nitrate 

leaching. Maine’s Coastal Nonpoint Source Control Program and Division of Health Engineering 

favor shallow leach field installations to take advantage of the treatment potential in the upper 

soil horizon. Monitoring of shallow SWISs in Maine found total nitrogen reductions of 41 to 91 

percent (Leyden, 1999). 

In those areas where nitrogen is a problem pollutant, existing systems may be retrofitted to 

improve nitrogen removal, and new systems should include treatment components that are 

capable of removing nitrogen. Retrofitting upon failure of systems in these areas is 

recommended. Also, it is important to consider the density and overall discharge of on-site 

treatment systems. As the density of residences increases, lot sizes decrease and nitrogen impacts 

on surface and ground waters intensify. Lots of 1/2 acre to 5 acres are generally the minimal 

requirement of prescriptive codes for siting conventional on-site systems. The Code of 

Massachusetts Regulations identifies certain wellhead protection areas, public water supply 

recharge zones, and coastal embayments as nitrogen-sensitive areas and requires treatment 

systems in those areas to meet nitrogen loading limitations. For example, recirculating sand 

6-24 
Management Measure 6: New and Existing On-Site Wastewater Treatment Systems 

filters or equivalent technologies must be employed to limit total nitrogen (nitrogen as nitrate, 

nitrite, or ammonia) concentrations in effluent to no more than 25 mg/L and to remove a 

minimum of 40 percent of the influent nitrogen load. All systems in nitrogen-sensitive areas 

must discharge no more than 440 gallons of design flow per day per acre unless system effluent 

meets a nitrate standard of 10 mg/L or other nitrogen removal technologies or attenuation 

strategies are used (Code of Massachusetts Regulations, 1995). Any zone requiring such systems 

should have a management entity to assure sustained performance by these systems. 

One of the most effective nitrogen removal methods is the recirculating sand filter (Table 6.8), 

which has been shown to remove approximately 50 percent of the total nitrogen from residual 

wastewater (USEPA, 1993b and 2002a). Other innovative and alternative systems have been 

developed to address site constraints and to provide improved on-site treatment and dispersal of 

wastewater. Many of these systems use advanced nutrient removal processes to enhance the 

ability of on-site systems to protect surface and ground water quality. Such systems include 

recirculating sand (nitrogen removal) and anaerobic upflow filters (denitrification), intermittent 

sand filters (nitrification), and subsurface-flow constructed wetlands (denitrification). The 

subsurface flow constructed wetland (i.e., vegetated submerged beds) and anaerobic upflow 

filters require nitrification of septic tank effluent before it enters the treatment process. 

Nitrification technologies include trickling filters with highly permeable plastic media, singlepass media filters, aerated sequencing batch reactors, activated sludge treatment systems, and 

filtration systems that use peat or other materials in place of sand. Table 6.8 presents an 

estimated performance summary for a variety of treatment technologies. 

Another primary nutrient, phosphorus, is often the limiting factor for algal growth and 

eutrophication in freshwater systems. Because other nutrients necessary for the growth of algae 

and other aquatic plants are usually present in inland waters, low concentrations of phosphorus 

can lead to a direct increase in growth. Studies have shown that lakes with phosphorus 

concentrations as low as 20 to 30 parts per billion can become highly productive or eutrophic. 

Conventional OWTSs (septic tanks/SWISs) remove only 15 to 30 percent of the phosphorus in 

raw wastewater. Favorable phosphorus removal conditions exist for SWISs in most soils of the 

United States, but some phosphorus loading problems might be encountered in areas with older 

systems, highly permeable soils (e.g., sands), mineral-poor soils, nearby surface waters, and high 

system densities. Some technologies can enhance phosphorus removal (e.g., sand filters with 

high iron-content sand, sequencing batch reactors operated in certain modes). 

6-25 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Table 6.8: Wastewater constituents of concern and representative estimates of 

concentrations in the effluent of various treatment units (adapted from Siegrist et al., 

2000). 

Tank-based treatment unit effluent concentrations 

Constituents of concern 

Direct or 

indirect 

measures 

Domestic STEa

Domestic STE with N-removal recyclebAerobic unit effluent Recirculating sand filter effluentc

Recirculating foam or textile filter effluentc

SWIS 

percolate 

into 

ground 

water at 

3- to 5-ft 

depth (% 

removal) 

Oxygen demand BOD5 (mg/L) 140-200 80-120 5-50 2-15 5-15 >90 

Particulate solids TSS (mg/L) 50-100 50-80 5-100 5-20 5-10 >90 

Nitrogen Total N (mg N/L) 40-100 10-30 25-60 10-50 30-60 10-20 

Phosphorusd Total P (mg P/L) 5-15 5-15 4-10 3-9 4-10 0-100 

Bacteria (e.g., 

Clostridium perfringens, 

Salmonella, Shigella) 

Fecal coliform 

(organisms per 

100 mL) 

106-108 106-108 103-106 101-103 101-103 >99.99 

Viruse (e.g., hepatitis, 

polio, echo, coxsackie, 

coliphage) 

Specific virus 

(pfu/mL) 

0-105 0-104 0-104 0-103 0-103 >99.9 

Organic chemicals (e.g., 

solvents, petrochemicals, pesticides) 

Specific organics 

or totals (:g/L) 

0 to 

trace 

0 to 

trace 

0 to 

trace 

0 to 

trace 

0 to 

trace 

>99 

Heavy metals (e.g., Pb, 

Cu, Ag, Hg) 

Individual metals 

(:g/L) 

0 to 

trace 

0 to 

trace 

0 to 

trace 

0 to 

trace 

0 to 

trace 

>99

a Septic tank effluent (STE) concentrations given are for domestic wastewater. However, restaurant STE is markedly 

higher, particularly in BOD5, COD, and suspended solids, while concentrations in graywater STE are noticeably 

lower in total nitrogen. 

b N-removal accomplished by recycling STE through a packed bed for nitrification with discharge into the influent 

end of the septic tank for denitrification. 

c Operated in recirculating mode. 

d P-removal by adsorption or precipitation is highly dependent on media capacity, P loading, and system operation. 

e Episodically present at high levels.

6.3.1.5.2 Septic tanks 

Septic tanks are designed to retain a minimum 24- to 48-hour wastewater flow and are usually 

the first component in OWTSs. Additional treatment components (e.g., soil absorption field, 

sand/media filter) are necessary because the quality of septic tank effluent is not adequate for 

direct discharge. The septic tank should be watertight for two reasons: (1) infiltration into the 

tank can cause hydraulic overloading of treatment and/or dispersal components; and (2) leaks 

can cause discharge of scum and sludge to subsequent processes and increase potential for 

surface and ground water contamination. Many states and counties require tanks to be watertight. 

For example, Suffolk County, New York, regulations state that “all joints shall be sealed so that 

the tank is watertight and certified as to watertightness after installation. Tanks that are cast in 

place must be certified by a licensed professional engineer and, as a minimum, have the floor and 

walls monolithically poured.” Oregon septic tank standards stipulate that tanks are to be tested 

by filling them with water to a level 2 inches above the point of riser connection to the top of the 

tank. Leakage of no more than 1 gallon during a 24-hour period must be demonstrated. Because 

of leakage concerns, cast concrete and polyethylene tanks are preferred over those constructed of 

metal, redwood, concrete block, brick, or other materials, unless equipped with a watertight liner. 

6-26 
Management Measure 6: New and Existing On-Site Wastewater Treatment Systems 

Septic tanks should be fitted with a regularly serviced effluent screen, commonly called a filter, 

at the outlet pipe. Several states and localities (e.g., Connecticut, Georgia, Florida, Alabama, 

North Carolina, Contra Costa County, California) now require septic tank screens to help protect 

the integrity of the SWIS for long-term performance (Schaub, 2000; Stuart, 2000). Screens not 

only prevent the discharge of neutrally buoyant solids and reduce TSS during tank upsets, but 

also provide an early warning sign that an inspection is needed, since they will clog and cause 

plumbing fixtures to drain poorly as they screen solids attempting to exit the tank through the 

outlet pipe. 

Because septic tanks need to be serviced, the top of a septic tank riser should extend above the 

ground surface. Older installations can be difficult to locate when these features are not provided. 

Both septic tanks and SWISs are usually required to be at least 50 to 100 feet from any surface 

water body, but this setback might not be adequate in some cases (e.g., high-porosity soils, high 

water tables). Septic tanks should be inspected and pumped every 3-5 years. 

6.3.1.5.3 Subsurface wastewater infiltration systems 

Infiltration trenches containing perforated pipe and stone are the most widely used method for 

treating and dispersing septic tank effluent, though other septic tank effluent infiltration 

approaches (plastic open-bottomed leaching chambers, perforated pipes encased in net-wrapped 

foam pellets, and alternate media such as tire chips) have been used successfully. SWIS trenches 

are typically about 2 to 4 feet deep and about 2 to 3 feet wide. Soils, surface water drainage, and 

the slope of the land influence the location of the tank and field (Dickey et al., 1996). For 

example, septic systems are usually required to be located downslope from all wells, although 

ground water might not always follow this gradient. Trenches typically range in length from 45 

to 100 feet. 

Infiltration occurs through the bottom and sides of the trench. Gravelly soils promote rapid 

movement of wastewater contaminants, and poor-permeability soils (clays, etc.) require very 

large SWISs to accept the entire wastewater volume. Shallow trenches are generally preferred to 

deeper trenches because the upper soil horizons are usually more permeable and greater aeration 

and evapotranspiration can occur. A reserve area for future repairs or additions to the drainage 

field is often required by state code. 

Septic tank effluent can be distributed to soil absorption system components by gravity, dosing, 

or uniform application. Dosing refers to periodically (e.g., 4 to 24 times per day) releasing 

effluent to the SWIS using a pump or siphon after a predetermined quantity has accumulated. 

Similarly, uniform application stores the effluent for a short time, after which it is pumped 

through smaller-diameter perforated pipes throughout the entire trench length to achieve uniform 

distribution. Distribution boxes have long been a source of poor performance in gravity-dosed 

systems, and they must be inspected frequently after initial installation because uneven settling 

causes uneven distribution of effluent. Ports with cam-type levelers can be adjusted to 

compensate for settling where regular inspection is required. Distribution boxes that do not have 

access ports or are not inspected or maintained are not recommended. 

Uniform application can result in the least amount of infiltrative surface clogging and greatest 

treatment efficiency. Maintenance of trenches and beds is minimal, particularly if the tank is 

pumped regularly. Alternating SWIS systems are especially effective because they allow the use 

6-27 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

of one or more leaching systems while others rest for six months to a year to restore their 

effectiveness. 

Most SWISs are designed to oxidize carbonaceous organics and convert the ammonium in septic 

tank effluent to nitrate by providing an aerobic environment. Nitrogen removal capabilities of 

SWISs are minimal and depend in part on temperature. Nitrate is water-soluble and travels freely 

to ground water. Elevated nitrate concentrations in ground water used as drinking water can 

cause the childhood illness methemoglobinemia (blue baby syndrome), can cause problems 

during pregnancy, and can present a risk to poultry livestock. In soils with no denitrifying 

capability, nitrate can travel with the ground water to nearby surface waters. Nitrogen loadings in 

coastal areas can cause eutrophication and related problems (e.g., low dissolved oxygen) that 

impair the life functions of desirable aquatic biota. 

Some clogging of infiltrative surface pores from biomass and slimes produced by natural 

wastewater decomposition processes occurs under normal conditions. In coarser soils, this 

“biomat” improves treatment performance. Research conducted in Marion County, Florida, 

found that the predominant cause of hydraulic failure in systems less than five years old was 

hydraulic overload. After 15 years of service, root clogging was the cause of hydraulic failure in 

most cases. In general, SWISs located high in the soil profile provide access to both carbon 

(from organic matter) and oxygen (diffusion from ground surface), two elements needed for 

biochemical wastewater decomposition processes. Shallow placement also maximizes vertical 

separation between the infiltrative surface and ground water. 

The vertical distance between the soil infiltration system and ground water is an important 

consideration. If seepage from the SWIS reaches the ground water in an area where unsaturated 

soil depth is inadequate, it could contaminate drinking water supplies. Furthermore, during wet 

seasons, ground water might rise into the SWIS, causing sewage to move upward toward the 

ground surface. This is especially important to consider in areas with a high water table 

(Lockwood, 1997) or in areas with poor permeability. Dickey et al. (1996) recommend that 

SWISs be placed at least 4 feet above the ground water table during the wettest season. The type 

of soil also influences the potential for ground water contamination. If sewage is applied to 

coarse soils, for example, the potential for contamination may be higher (Dickey et al., 1996). 

Clays that crack when dry or contain other types of macropores can also have a high 

contamination potential. 

Installation of a conventional septic tank with a SWIS typically costs between $3,000 and $5,000 

per home, but costs vary widely based on site-specific physical and regulatory limitations. 

6.3.1.5.4 Leaching chambers 

Molded plastic leaching chambers (see Figure 6.3) have been used in lieu of trench-based 

perforated pipe and aggregate infiltration systems to distribute septic tank effluent to the soil for 

final treatment. A typical leaching chamber infiltration system consists of interconnected archshaped bottomless chamber segments, installed below grade in level beds that comprise the drain 

field network. Aggregate is not needed, although porous media (e.g., gravel) is often used to fill 

in around the exterior of the vented chamber sidewalls to accommodate delivery of effluent 

through the sidewalls when ponding in the chambers occurs. Sizing of the network is based on 

wastewater characteristics, flows, and site conditions (soils, depth to groundwater/bedrock, etc.). 

6-28 
Management Measure 6: New and Existing On-Site Wastewater Treatment Systems 

Figure 6.3: Leaching chamber subsurface wastewater infiltration system (Hoover et al., 

1996). 

Chamber systems have increased in use due to their performance, cost, light weight, and ease of 

installation. 

6.3.1.5.5 Alternative systems 

Several states have adopted provisions for the use of alternative and innovative technologies. 

Massachusetts has adopted a provision of its state environmental code that allows “approval of 

innovative (dispersal) systems if it can be demonstrated that their impact on the environment and 

hazard to public health is not greater than that of other approved systems” (Code of 

Massachusetts Regulations, 1995). Commonly referred to as Title 5, this legislation requires 

evaluation of pollutant loadings as well as management requirements prior to approval of 

alternative systems (Venhuizen, 1992). 

The State of Maryland’s regulations assert that the Maryland Department of the Environment 

(MDE) and the approving authority “shall consider all possible methods for correcting existing 

system failures and providing facilities for homes that lack indoor plumbing and, based on a 

case-by-case evaluation, provide the best technical guidance in attempting to resolve existing 

pollution or public health problems” (Code of Maryland Regulations, 2001). Alternative 

technology (with appropriate management) can be used for new construction on existing lots of 

record where site limitations prevent the use of conventional on-site systems. State regulations 

require that the local health unit and MDE monitor these systems for not less than two years. 

More information on the alternative technologies described below is available from the National 

Small Flows Clearinghouse Environmental Technology Initiative 

(http://www.nesc.wvu.edu/nsfc/nsfc_ETI.htm) and EPA 

(http://www.epa.gov/owm/decent/treat.htm). An extensive list of links to public and private 

sector OWTS resources can be found at 

http://centreforwaterresourcesstudies.dal.ca/cwrs/onsite/info.htm. For information on loading 

rates, design, and performance capabilities for conventional and alternative treatment systems, 

refer to the Onsite Wastewater Treatment System Manaual (USEPA, 2002a). Table 6.9 provides 

a summary of capital and maintenance cost data for selected OWTS technologies. 

6-29 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Table 6.9: Summary of estimated capital and operation and maintenance costs for OWTSs 

(adapted from Hoover, 1997). 

Costs (dollars) 

System Type 

Total 

materials 

& 

installation 

Present 

value of 

total 

O&M1

Total 

over life 

of 

system 

Amortized 

monthly 

materials & 

installation 

Average 

monthly 

present 

value of 

O&M1

 

Average 

monthly 

over the 

life of the 

system 

Septic Tank and Gravity Distribution 

Alone 2,504 6,845 9,349 20 19 39 

With chambers 3,336 7,032 10,368 27 20 46 

With styrene foam 2,846 6,920 9,767 23 19 42 

With large diameter pipes 3,816 7,156 10,971 31 20 51 

With pressure manifold 4,774 7,707 12,482 38 21 60 

With pressure manifold and chambers 5,593 7,889 13,482 45 22 67 

With pressure manifold and styrene foam 5,103 7,777 12,881 41 22 63 

With pressure manifold large-diameter pipes 6,073 8,013 14,085 49 22 71 

With sand filter pretreatment 7,296 12,069 19,364 59 34 92 

With peat filter pretreatment 11,808 12,604 24,412 95 35 150 

With recirculating sand filter pretreatment 6,226 12,059 18,285 50 33 84 

With wetland cell 5,574 23,231 28,805 45 65 109 

With 18" fill mound 4,507 6,850 11,357 36 19 55 

With 18" fill mound and chambers 5,326 7,032 12,357 43 20 62 

Septic Tank and LPP Distribution 

Alone 4,523 12,319 16,843 36 34 71 

With sand filter pretreatment 10,223 13,338 23,561 82 37 119 

With recirc. Sand filter pretreatment 8,232 13,007 21,239 66 36 102 

In at-grade system 4,590 12,345 16,935 37 34 71 

Septic Tank and Drip Distribution 

Alone 11,163 13,082 24,245 90 36 126 

With sand filter pretreatment 15,994 14,101 30,095 129 39 168 

With recirculating sand filter pretreatment 14,872 14,094 28,966 120 39 159 

With sand filter pretreatment and chlorine 

disinfection 16,408 21,244 37,652 132 59 191 

With recirculating sand filter pretreatment 

and chlorine disinfection 15,285 21,237 36,522 123 59 182 

with sand filter pretreatment and UV 

disinfection 17,867 21,655 39,522 144 60 204 

With recirculating sand filter pretreatment 

and UV disinfection 16,744 21,757 38,501 135 60 195 

Septic Tank and Gravity Distribution 

Alone 2,504 6,845 9,349 20 19 39 

With chambers 3,336 7,032 10,368 27 20 46 

Septic Tank and Spray Irrigation 

With sand filter pretreatment and chlorine 

disinfection 11,890 20,670 32,580 96 57 153 

With recirculating sand filter pretreatment 

and chlorination 10,768 20,663 31,431 87 57 144 

With sand filter pretreatment and UV 13,349 21,190 34,539 107 59 166 

With recirculating sand filter pretreatment 

and UV 12,227 21,183 33,410 98 59 157 

Denitrification System Black Water and Gray Water Separation 

With gravity distribution 9,963 13,508 23,471 80 38 118 

With LPP distribution 12,565 15,070 27,635 101 42 143 

6-30 
Management Measure 6: New and Existing On-Site Wastewater Treatment Systems 

Table 6.9 (continued).

Costs (dollars) 

System Type 

Total 

materials 

& 

installation 

Present 

value of 

total 

O&M1

Total 

over life 

of 

system 

Amortized 

monthly 

materials & 

installation 

Average 

monthly 

present 

value of 

O&M1

 

Average 

monthly 

over the 

life of the 

system 

Other Types 

Aerobic treatment unit and gravity 

distribution 8,037 36,406 44,443 65 101 166 

Septic tank and pressure-dosed sand mound 

system 4,863 12,407 17,269 39 34 74 

Septic tank filter or screen (installation or 

retrofit into existing tank only) 200-400 938 1,250 1 <1 <1 

Note: These numbers could be considered in the low to moderate range and may vary in other regions because of differences in 

material and labor costs. 

1

 O&M = Operation and Maintenance

Regardless of the type of soil, sand, or other medium used for the absorption field, some sort of 

minimal maintenance is often required. It is important to restrict the operation of heavy 

equipment within the area proposed for soil absorption fields to prevent compaction of the soil 

structure and system clogging. Vehicles or other heavy equipment should not be operated over 

previously installed absorption fields or filters for the same reason. Concrete tanks are often 

capable of withstanding heavy loads, but operation of vehicles or other heavy equipment directly 

above them can cause settling or structural failure that can affect tank performance. Finally, 

because of the clogging effect of roots, vegetation above absorption fields and filter media 

should be restricted to types with short root structures. Trees or shrubbery should be immediately 

removed from absorption fields or filter medium installations. 

6.3.1.5.6 Elevated systems 

Mound systems are alternative soil absorption systems typically used at sites where insufficient 

ground water separation distances or slow-permeability soil conditions exist (see Figure 6.4). 

Mound systems are usually designed so that the effluent from the septic tank flows to a dosing 

tank and is then pumped to the top of the mound, which is constructed above the natural soil 

surface. The mound consists of a layer of suitable sand fill, an absorption bed filled with 

aggregate within the sand fill, and a covering layer of topsoil. The topsoil layer should be at least 

6 inches deep and serves as a growth medium for vegetation. Converse and Tyler (2000) advise 

that mounds not be built on grades steeper than 25 percent. 

At-grade systems are similar to mound systems, but the absorption bed is built directly on the 

ground surface, with aggregate placed on tilled soil instead of on top of raised sand. At-grade 

systems are typically designed for sites unsuitable for subsurface systems, but with lessrestrictive conditions than sites where mounds would be needed (Converse and Tyler, 2000). 

Pollutant removal effectiveness and operation and maintenance are similar to those of 

conventional systems with pressurized distribution. A mound system is more expensive to install 

than a typical soil absorption trench system. The cost of a complete mound system, including a 

septic tank, is typically $7,000 to $12,000 installed. Operation and maintenance include septic 

tank pumping every 3 to 5 years; annual or semiannual inspection of the pump, float switches, 

tank, and dosing chamber; and maintenance of vegetative cover (i.e., grass) to prevent erosion. 

6-31 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Mound

Plowed Layer Aggregate

% Slope

Sand

Fill

Observation Tube

Fabric

Topsoil

Subsoil

Pump

Septic Tank

From

House

Dosing Chamber

Scum

Sludge

Mound

Plowed Layer Aggregate

% Slope

Sand

Fill

Observation Tube

Fabric

Topsoil

Subsoil

Pump

Septic Tank

From

House

Dosing Chamber

Scum

Sludge

Figure 6.4: Schematic of a typical mound system (Ohio State University, no date). 

6.3.1.5.7 Intermittent sand/media filters 

An intermittent filter system receives and treats effluent from the septic tank via sand or other 

media (e.g., peat or composite materials) before it is discharged to the soil absorption field. 

Periodic, uniform dosing of septic tank effluent is distributed to the surface of the sand/media 

filter. The filter consists of a bed (either open or buried) of granular, synthetic, or organic 

material from 24 to 36 inches deep. Microorganisms living and growing on the filter medium 

consume nutrients and other wastes and facilitate aerobic decomposition of organic matter in the 

wastewater. The treatment medium is underlain by leveled rock or gravel and collector drains. 

Siphon or pressure distribution of septic tank effluent is used to dose wastewater to the surface of 

the media. Free access filters (media exposed to the atmosphere) should be covered with 

removable covers to prevent operation and maintenance problems (such as those caused by dust 

and rain), and should include insulation in cold and wet regions. 

Intermittent media filters might become clogged as the pore space between the grains of the 

medium begins to fill with excessive amounts of inert biological materials. Resting the filter for 

several months in warm weather will restore hydraulic conductivity (Tyler et al., 1985). Free 

access filters should be checked every three to four months to prevent surface problems. Periodic 

raking is recommended to remove leaves and other debris where the system is not covered. 

Intermittent sand filters typically produce high-quality effluents with BOD5 and suspended solids 

concentrations below 10 mg/L (Tchobanoglous and Burton, 1991). Nitrogen compounds are 

almost completely nitrified if the filter remains aerobic, although nitrification rates might fall 

during cold weather. Total nitrogen removal rates average 15 to 35 percent (USEPA, 2002a). 

Installation cost ranges from $5,000 to $10,000. Systems that use peat or other organic media in 

place of the soil/sand filter media have been installed in several areas of the country to serve 

single- and multiple-family residences. This technology has shown excellent results in many 

applications but is still under study and considered a provisional application subject to 

monitoring in most jurisdictions. 

6-32 
Management Measure 6: New and Existing On-Site Wastewater Treatment Systems 

Washington Island, Wisconsin, covers a 36-square-mile area. Its geology consists of shallow soils and 

fissured, cavernous carbonate bedrock. Sinkholes are not uncommon and the threat of ground water 

contamination is real. Conventional systems serve older developments on the island, but the potential 

for ground water contamination from pathogens and nitrate spurred interest in alternative 

technologies. As part of a demonstration project, recirculating sand filters were installed and evaluated 

for 2 years. The demonstration project showed that total nitrogen could be reduced by 60 to 90 

percent. Water quality was also improved by inserting an anaerobic upflow filter between the septic 

tank and the sand filter dosing tank.

Sand Filter System, Washington Island, Wisconsin

Operation and maintenance include monitoring influent and effluent, inspecting the dosing 

equipment, maintaining the filtration medium surface (i.e., raking and replacing as needed), 

checking the discharge orifices for buildup or blockage, and flushing the distribution manifold 

annually. Costs for operation and maintenance of these systems include three or four visits per 

year ($100 to $150/year), in addition to septic tank maintenance. 

6.3.1.5.8 Recirculating sand/media filters 

A recirculating sand/media filter is a modified intermittent filter that recirculates the effluent 

from the filter through the septic tank and/or the recirculation tank before it is discharged to the 

wastewater infiltration system. The addition of the recirculation loop in the system enhances 

pollutant removal effectiveness by providing a denitrification step (i.e., in the septic or 

recirculating tank) in the treatment process. Nitrogen is both nitrified (in the media filter) and 

denitrified in these systems, resulting in 40 to50 percent or more (if enhanced) nitrogen removal. 

Recirculation rates of 3:1 or higher are generally recommended. Recirculating media filters can 

be used in new, on-site systems or applied to retrofits of failing conventional systems (Bruen and 

Piluk, 1994), particularly at sites with nitrogen concerns. Recirculating media filter effluent 

might also be appropriate for soil absorption systems with low-permeability soils. 

BOD and suspended solid concentrations in the effluent are typically less than 10 mg/L (Roy and 

Dube, 1994; Bruen and Piluk, 1994; Loudon, 1996). Recirculating sand filters typically cost 

$8,000 to $11,000. 

Operation and maintenance include monitoring effluent; inspecting the dosing equipment; 

maintaining the filtration surface (i.e., raking as needed); checking the discharge orifices for 

buildup and blockage; and flushing the distribution manifold annually in addition to septic tank 

maintenance. 

6.3.1.5.9 Anaerobic upflow filters 

An anaerobic upflow filter (AUF), which may resemble a septic tank filled with gravel, is 

designed so that the effluent flows up through the bottom of the AUF filter media (e.g., d-inch 

gravel). Anaerobic bacteria that convert nitrate in the influent to nitrogen gas grow on the 

surfaces of the filter medium. Septic tank effluent is gravity-dosed or pumped (depending on site 

conditions) to the bottom of the AUF and up through the filter to the top, where a collection pipe 

transports it to a dosing chamber and/or SWIS for final discharge. A nitrogen-removal system 

may include a septic tank, a sand filter, an AUF, and a soil absorption field. AUFs are relatively 

small (e.g., 4 feet deep and 6 feet in diameter) (Boyle, 1995) and sized to allow retention times of 

24 to 48 hours. 

6-33 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Zielinski et al. (2000) undertook a study to compare nutrient export from several conventional 

development projects and the same projects designed using alternative open space strategies (see 

Management Measure 4 for a discussion of conventional and alternative development scenarios). One 

site was a low-density residential subdivision in Maryland. In the conventional design, each lot had an 

on-site private septic system and the neighborhood had a septic reserve field of approximately 10,000 

square feet. When the site was redesigned to preserve open space, the individual septic systems 

were replaced with shared septic systems that used more advanced recirculating sand filter 

technology with better nutrient removal capacity and lower construction and installation costs. When 

the two development scenarios were modeled to determine relative rates of nutrient export, the 

redesigned septic system showed a substantial decrease in nutrient output. However, despite the use 

of more advanced technology, septic systems remained the predominant source of exported nutrients. 

Nutrient Export from Conventional vs. Open Space Development in Maryland 

Total nitrogen concentrations from AUFs treating fully nitrified influent can range from less than 

3 to 23 mg/L or higher, with removal efficiencies of approximately 60 to 70 percent. Boyle 

(1995) reported average total nitrogen concentrations below 15 mg/L in a recirculating sand 

filter-anaerobic upflow filter system. The cost of the filter varies by manufacturer and is 

approximately $1,000 to $1,500. Operation and maintenance tasks are minimal, especially if the 

filter medium consists of large gravel (i.e., > 1 inch). Sand-sized media will clog and should not 

be considered. Inspection of wastewater levels in the septic tank and AUF filter tank, as well as 

periodic inspection of pumps, float switches, discharge orifices, and other components, should be 

conducted to ensure continuous performance. 

6.3.1.5.10 Cluster systems 

For the purposes of this guidance, a cluster system is defined as a collection of individual on-site 

systems that provide primary treatment in septic tanks at each site. Septic tank effluent is 

collected and routed to another site for further treatment. Other designs in which primary 

treatment occurs at the treatment site instead of the septic tank are also possible. Collection and 

movement of effluent to the final treatment site can be accomplished by gravity flow or pumps. 

Additional treatment for cluster systems may involve the use of conventional SWISs, sand 

filters, AUFs, constructed wetlands, aerobic lagoons, or aerobic treatment. The use of cluster 

systems can be advantageous in the case of inadequate soil, groundwater, or space at individual 

homes, or when better soil at is available at another location in the development. 

6.3.1.5.11 Constructed wetlands 

Constructed wetlands have traditionally been used for polishing effluent that has already had 

some degree of treatment. Vegetated submerged beds (VSBs), also known as submerged 

constructed wetlands, subsurface flow constructed wetlands, or plant rock filters (see Figure 6.5), 

are designed primarily to reduce concentrations of BOD and suspended solids in wastewater 

effluent from the septic tank. VSBs consist of horizontal flow gravel filters with wetland-type 

vegetation (e.g., cattails, canna lilies) and are usually underlain with an impermeable liner (e.g., 

plastic sheeting). The vegetation has a minimal role in treatment in this application. Residential 

vegetated submerged beds are normally followed by subsurface infiltration trenches or chambers. 

The performance of constructed wetlands is not significantly degraded in colder climates during 

winter months because removal is by physical and chemical processes. Recent tests that 

6-34 
Management Measure 6: New and Existing On-Site Wastewater Treatment Systems 

Inlet Stone 

Distribution

Slope 1% Rhizome

Network

Soil or 

Gravel

Watertight

Membrane

Effluent 

Outlet

Height

Variable

Inlet Stone 

Distribution

Slope 1% Rhizome

Network

Soil or 

Gravel

Watertight

Membrane

Effluent 

Outlet

Height

Variable

Figure 6.5: Components of a vegetated submerged bed. 

incorporated a submerged aeration line in the wetland cell have shown promise in facilitating 

nitrification/denitrification (Wallace, 2000). 

Constructed wetlands are configured as free-water surface wetlands, which can facilitate aerobic 

treatment processes, or subsurface flow wetlands, which are generally anaerobic. Removal rates 

for fecal coliform, BOD, and suspended solids can be as high as 90 percent for a gravel-based 

VSB (White and Shirk, 1998). However, removal of nitrogen and phosphorus compounds (e.g., 

ammonium, nitrate, SRP) is typically much less. Nitrogen removal can be enhanced through 

designs that accommodate nitrification-denitrification processes—i.e., aerobic treatment 

followed by anaerobic treatment zones—but significant phosphorus removal is much more 

difficult to achieve (USEPA, 2001a). Estimated costs for VSBs range from approximately 

$10,000 to $20,000 for a system serving a typical residence. Maintenance tasks include removing 

dead vegetation; inspecting and cleaning the inlet and outlets; inspecting wastewater levels in the 

tank and filter bed; and ensuring wastewater levels do not rise above the filter medium. 

6.3.1.5.12 Sequencing batch reactors

A sequencing batch reactor (SBR) is a modified cyclically aerated and decanted activated sludge 

treatment system. The SBR carries out aeration, sedimentation, and clarification via timed cycles 

in the same tank. Continuously fed SBRs are compartmented to reduce short-circuiting. SBRs 

remove BOD and TSS from wastewater. Modification to the operational mode can enhance 

removal of phosphorus and nitrogen. Development of reliable and versatile control systems has 

been a major factor in the increased use of SBRs during recent years. However, repair and 

replacement costs and operator knowledge requirements should be considered in decisions 

regarding this technology. 

6-35 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

SBRs can be used for new developments or connected to existing septic systems and can be 

designed to collect effluent from multiple septic tanks for treatment at a common site. SBRs can 

be sited in relatively small areas of only a few hundred square feet. SBR costs, operation, and 

maintenance requirements are greater than those of conventional on-site systems. SBRs can be 

suitable alternatives for sites where high-density development and/or unsuitable soils preclude 

adequate treatment of effluent by conventional systems. 

With appropriate design and operation, SBR plants have been reported to produce high-quality 

effluents with very good removal rates for BOD and TSS. Typical ranges of CBOD5

(carbonaceous 5-day BOD) are from 5 to 15 mg/L, while TSS levels can range from 10 to 30 

mg/L in well-operated systems. Fecal coliform removal of 1 to 2 logs can be expected (USEPA, 

2002b). By using an anaerobic-aerobic operating mode, significant nitrogen and phosphorus 

removals are also possible. 

6.3.1.5.13 Aerobic treatment units 

Packaged aerobic treatment units have been used for residential on-site use for nearly 40 years. 

Treatment unit storage volumes can provide a hydraulic retention time of several days based on 

typical household flows. These systems require regular supervision, operation, and maintenance 

to be effective. Since maintenance has been a particular problem with these units, requiring a 

perpetual maintenance contract at the time of permitting is strongly recommended. Packaged 

aerobic treatment units generally include pretreatment by settling (usually in a septic tank) to 

remove fats, oils, grease, and solids. Effluent is usually discharged to a SWIS. When additional 

treatment (e.g., filtration, disinfection, etc.) is provided, discharge to surface waters may be 

possible if a Clean Water Act Section 402 (National Pollutant Discharge Elimination System) 

permit is obtained. Power requirements can be significant for certain types of package plants. 

Mixed liquor solids must be disposed of regularly, so the system should be inspected at least 

every three months. 

Extended aeration units can achieve BOD concentrations ranging from 30 to 50 mg/L and 

suspended solids concentrations ranging from 40 to 60 mg/L in well-operating systems, often 

reflecting 75 to 95 percent removal efficiency (Kellam et al., 1993; Ayres and Associates, 1991; 

Tchobanoglous and Burton, 1991). Installing a sand filter or other polishing unit to treat 

wastewater after an extended aeration unit can improve BOD and suspended solids removal 

performance, although nitrate levels might increase as a result (Kellam et al., 1993). Costs 

typically range from $3,000 to $6,000 for an installed unit, with maintenance costs of $200 to 

$300 per year. 

6.3.1.5.14 Fixed film systems 

Fixed film systems feature media (e.g. plastic disks, pellets, gravel, tire chips, fabric media, foam 

pellets) with large amounts of surface area where microorganisms that digest wastes become 

attached and grow. Colonies of bacteria and other organisms develop into a biologically active 

slime layer that is sustained by nutrients and other constituents in the effluent. As wastewater 

flows over the media, colonies of microorganisms extract soluble organic matter and nutrients as 

a source of carbon and energy. Oxygen, which is required by these microorganisms, can be 

supplied by natural ventilation or by mechanical or diffused aeration within the wastewater. 

6-36 
Management Measure 6: New and Existing On-Site Wastewater Treatment Systems 

Fixed film systems include trickling filters (where the wastewater flows down through a bed of 

gravel, carbon-based, or composite media such as tire pellets, fabric strips, foam pellets, etc.) and 

rotating biological contactors (rotating plastic discs colonized by wastewater flora/fauna partially 

submerged in the wastewater). These systems require pretreatment of sewage in a septic tank. 

Final effluent can be discharged to a SWIS or reused. Disinfection is necessary if effluent may 

come into contact with humans or disease vectors. Both systems can achieve TSS concentrations 

of 60 to 80 mg/L and BOD levels of 80 to 90 mg/L. Maintenance includes periodic inspection of 

wastewater levels in the septic tank; inspection of pump switches and discharge orifices; and 

cleaning or replacement of the growth medium at regular intervals, or more frequently if 

clogging develops. 

6.3.1.5.15 Pressure distribution systems 

Low-pressure effluent distribution into the soil using technologies developed by the drip 

irrigation industry offers significant treatment performance improvements. Pumping effluent to 

the dispersal field typically creates a large flow surge that distributes effluent uniformly 

throughout the dispersal field. This minimizes localized overloading and the consequent potential 

for eventual failure (Venhuizen, 1995). Pressure systems are placed very high in the soil profile 

and use periodic dosing to distribute effluent to the soil matrix. Pressure distribution trenches are 

typically shallow and narrow, providing ease of installation and maximum carbon availability for 

treatment processes. Reaeration of the infiltrative surface and drying of the biomat between 

doses reduce potential clogging threats and help to ensure nitrification of ammonia in the septic 

tank effluent. Drip irrigation distribution lines are typically installed with a vibratory plow at 

shallower depths (i.e., 8-12 inches below surface grade) and should be preceded with 

pretreatment by a septic tank and fixed film filter to prevent clogging of emitters (USEPA, 

2002a). 

6.3.1.5.16 Evapotranspiration 

Evapotranspiration (ET) systems are designed to remove wastewater through evaporation and 

transpiration; they are used mostly in dry climates (e.g., Arizona, New Mexico). They have been 

used in wetter climates where ET potential is sufficiently high in certain months. Seepage from 

an ET system can be reduced or eliminated by using a plastic, PVC, or clay liner, but leaving the 

system unlined allows both percolation and evapotranspiration to occur. Wastewater is applied 

below the surface to the sand medium of the ET system. Water moves to the soil surface by 

capillary action for use by plants or is evaporated to the atmosphere. Performance strongly 

depends on climate, available surface area, and physical properties of the sand. Properly 

operating ET systems must evaporate or transpire more water than is applied as waste or 

collected during precipitation. More than 5,000 ET systems are in use in the United States. The 

cost of installation ranges from $10,000 to $15,000, but operation and maintenance costs are 

generally quite low. 

6.3.1.5.17 Spray irrigation 

Spray irrigation is commonly used to discharge septic tank effluent as irrigation water to 

hayfields or other vegetated areas not used to produce food crops. Spray irrigation can 

effectively dispose of effluent from OWTSs. However, strict controls on human contact with 

discharges that might contain pathogens are required. Design of spray irrigation systems must 

consider soil permeability, slopes, climate, and the water and nutrient needs of vegetation 

growing on the spray field. Additional treatment and disinfection of spray irrigation water is 

6-37 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

necessary if human contact with the spray field or wet vegetation is likely. Successful 

applications have been installed in shallow soils in the Northeast. It is recommended that effluent 

be treated prior to spraying to remove most BOD for odor-prevention. Spray devices should not 

be activated during wet weather, freezing temperatures, or saturated soil conditions. Because 

large buffer areas around the spray sites are usually required, extensive land is required, limiting 

this option to very large lots. 

6.3.1.5.18 Disinfection devices 

In some areas (e.g., source water protection areas and sites near recreational lakes, and coastal 

beaches), pathogen contamination from on-site systems is a major concern. Disinfection devices 

can be used in conjunction with the technologies summarized above to treat effluent for 

pathogens before it is discharged. The three most common methods of disinfection in the United 

States are chlorination, ozonation, and ultraviolet (UV) disinfection (NSFC, 1998). 

Installation of these devices in an on-site system increases its cost and adds to operation and 

maintenance requirements. Single-home chlorinators in non-dosed conventional OWTSs have a 

poor track record when applied without management oversight. These units can greatly overdose 

or not dose at all if proper operation and maintenance are not performed. Chlorine is a powerful 

biocide and can have significant impacts on aquatic biota at concentrations well below 1 mg/L. 

Some states (e.g., Maryland) have additional requirements for maximum chlorine concentrations 

in effluent or prohibit the use of halogen (i.e., chlorine and iodine) processes. UV units generally 

require controlled dosing of a high-quality influent (BOD of 30 mg/L and TSS of 30 mg/L or 

better) for consistent performance. Maintenance includes periodically cleaning UV tube surfaces 

to maintain integrity and inspecting the contact chamber to ensure that solids have not 

accumulated. Annual replacement of UV bulbs is suggested. UV units cost $1,000 to $2,000 

(installed) or about the same as tablet chlorinator units. Operation and maintenance costs for UV 

are about $150 to $200, similar to the chlorinator. 

6.3.1.5.19 Water separation systems 

A water separation system separates graywater from sinks, tubs, and appliances from toilet 

blackwater. The graywater is treated by using a somewhat smaller conventional OWTS or a 

SWIS. The blackwater can be treated in another OWTS or stored in a holding tank and 

periodically hauled off site for treatment or disposal. For extreme situations or for seasonal 

residents, some form of separation of toilet wastes from bath and kitchen wastes can be helpful. 

Most nitrogen discharges in residential wastewater come from human wastes, and they also 

provide almost half of phosphorus, TSS, and BOD. Use of holding tanks can be very expensive 

owing to the cost of $0.10 to $0.20 per gallon for pumping and hauling. 

6.3.1.5.20 Vaults or holding tanks 

Vaults or holding tanks are used to contain wastewater in emergencies or other temporary 

situations and to hold wastewater from a blackwater system. These systems require frequent 

pumping, which can be expensive if the total wastewater flow is contained. 

6.3.2 Operation and Maintenance Programs 

This chapter discusses two broad functions that have an impact upon on-site wastewater 

treatment systems: regulatory oversight and management. In the following discussion, oversight 

6-38 
Management Measure 6: New and Existing On-Site Wastewater Treatment Systems 

refers to the regulatory and enforcement functions (e.g., issuing permits, compelling compliance 

with local or state codes) typically performed by the regulatory authority (i.e., state health 

departments and their agents, which are usually local health departments). The term management 

includes other functions and services that may or may not fall under the direction of the 

regulatory authority, such as long-term planning, ensuring that septic tanks are pumped 

regularly, conducting periodic system inspections, arranging for financial assistance for 

installations/repairs, and other activities. 

Management services may be provided by a management entity separate from the regulatory 

authority, such as a sanitation district, contracted firm, or homeowners’ association. It is 

important to recognize that while the enforcement of codes and regulations (i.e., by the 

regulatory authority) provides a very basic level of protection for public health and 

environmental resources, the execution of management tasks (e.g., planning, monitoring, 

operation, maintenance, inspection) by a designated management entity helps to ensure that longterm system use meets established performance requirements. 

Implementation of the various management program elements will undoubtedly be subject to the 

authority of the regulatory agency or agencies, but may be accomplished by another management 

entity, such as a public or private utility, regional planning agency, or water monitoring council. 

Some management program elements may require special arrangements or agreements if they are 

to be performed by a separate management entity. For example, where state codes require the 

regulatory authority to oversee system design and permitting, a formal agreement would likely 

be required if an outside management entity assumed those duties. The exact nature of the 

relationship between the regulatory authority and any management entities servicing a particular 

jurisdiction will vary considerably and depend upon the capacity of the regulatory authority, state 

and local codes, and the ability of management entities to provide designated services in an 

acceptable manner. 

According to the U.S. Census Bureau (1997b), approximately 25 percent of the estimated 

112 million occupied homes in the United States are served by on-site systems, a proportion that 

has changed little since 1970. Distribution and density of homes with OWTSs varies widely by 

state, with a high of about 55 percent in Vermont and a low of around 9.8 percent in California. 

New England states have the highest proportion of OWTS-served homes: New Hampshire and 

Maine both report that about half of all homes are served by on-site systems. More than a third of 

homes in the southeastern states depend on OWTSs, including approximately 48.5 percent in 

North Carolina and about 40 percent in both Kentucky and South Carolina. 

More than half of the nearly 26 million homes with on-site treatment systems are more than 30 

years old (U.S. Census Bureau, 1997a, 1999) and a significant number report problems. A survey 

conducted by the U.S. Census Bureau (1997a) estimated that 403,000 homes experienced septic 

system breakdowns within a three-month period during 1997, with 31,000 reports of four or 

more breakdowns at the same home. Typical reported malfunction rates average between 1 and 5 

percent annually, with reported failure rates in a study conducted in the State of Washington 

ranging between 2.6 percent and 6.1 percent (USEPA, 1993b). It has been estimated that in some 

areas of Connecticut, 4 percent of on-site systems fail each year. The failure rate might be high 

because many on-site systems are approved in areas with unsuitable soil conditions. 

6-39 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Reported failure rates may underestimate true failure rates because they typically consider only 

plumbing backup and sewage surfacing, and not ground water or surface water contamination. 

Parsons Engineering Science (2000) reported that dye testing conducted for the Rouge River 

National Wet Weather Demonstration Project found failure rates (defined as short-duration 

appearance of dye in receiving waters) of 39 to 72 percent. Nelson et al. (1999) reported that 

estimates of partial and total system failure rates in some states range as high as 50 percent and 

more in some cases, but definitions of failure were highly variable and included all systems that 

were not designed according to the states revised codes. 

Besides design, installation, and maintenance problems, regional hydraulic overloading (i.e., 

hundreds or thousands of densely sited systems discharging into a single ground water aquifer or 

subwatershed) can cause OWTSs to fail to meet requirements for protection of public health and 

water quality. Other factors include lack of maintenance and system age. In some areas, on-site 

systems are installed at a density that exceeds the capacity of the local soil to assimilate 

hydraulic and pollutant discharge loads. In addition, the design life of many OWTSs built 

between 1960 and 1980 has been exceeded. System owners are not likely to repair or replace 

aging OWTSs unless sewage backup, septage pooling on lawns, or targeted monitoring and 

failure documentation occurs. Approaches for reducing operation and maintenance failures 

through development of management activities and systems are outlined below. 

The following sections describe recommended management measures that promote the 

protection of public health and water resources from risks linked to on-site systems. More 

information on OWTS management measures and system technologies, as well as case studies 

from across the nation, are available from EPA at http://cfpub.epa.gov/owm/septic/home.cfm and 

from the National Small Flows Clearinghouse at http://www.nesc.wvu.edu/nsfc/nsfc_index.htm. 

A model framework for management programs and other information on OWTS issues is posted 

by the National On-Site Wastewater Recycling Association at http://www.nowra.org/. 

6.3.2.1 Development of system inventories and assessment of maintenance needs 

System inventories are critical elements of an effective on-site/decentralized system management 

program. An inventory is essential to both long- and short-term planning. Knowledge of factors 

such as system location, type, age, maintenance schedule, and potentially affected water 

resources is necessary to predict watershed and site-specific pollutant loadings. This knowledge 

is also needed to achieve a community’s public health, environmental, and fiscal goals. 

Inventories can also give owners information regarding the proper operation and maintenance of 

their systems. A typical inventory will contain information such as: owner name, contact 

information, system type, location, installation date, design capacity, and last date of service. 

Clermont County, Ohio, developed an OWTS owner database by cross-referencing water line 

and sewer service customers (Caudill, 1998). Because most people in the county were public 

water line customers, subtracting those who were also connected to the public sewer system 

yielded a database of nearly all the OWTS users. Contact information from the database was 

used to mass-mail information on system operation and maintenance and the county’s new 

inspection program to 70 percent of the target audience. Other approaches used in the Clermont 

County outreach program were advisory groups, homeowner education meetings, news releases 

6-40 
Management Measure 6: New and Existing On-Site Wastewater Treatment Systems 

and interview programs, meetings with real estate agents, presentations at Farm Bureau 

meetings, displays at public events, and targeted publications. 

System inventories are essential elements for management programs, and most jurisdictions 

maintain databases of new systems through their permitting programs. However, older systems 

(e.g., those installed prior to 1970) are often not included in those data files. Some on-site 

management programs or other entities conduct inventories of older systems when they are 

included in a special study area. For example, Cass County and Crow Wing County, Minnesota, 

have developed projects to inventory and inspect systems at more than 2,000 properties near 

lakes in the north-central part of the state (J. Sumption, Deputy Director of Cass County, 

Minnesota, Environmental Services, 2000). The project inventoried but did not inspect systems 

that were less than five years old unless a complaint or other report indicated possible problems. 

Costs for inventorying and inspecting 234 systems in one lake watershed totaled $9,000, or 

nearly $40 per site (J. Sumption, Deputy Director of Cass County, Minnesota, Environmental 

Services, 2000). 

In some cases, data necessary for on-site system management may be held and administered by 

other agencies. For example, land and water resource characterization data are often collected, 

stored, and analyzed by environmental or planning agencies. Developing data-sharing policies 

with other entities through cooperative agreements can help all organizations involved with 

health and environmental issues improve their efficiency and overall program performance. The 

RME should ensure that data on existing systems are available to health and water resource 

organizations (usually regulatory authorities) so that their activities and analyses reflect this 

important aspect of public health and environmental protection. 

Education for system owners is an important component of the outreach for management 

programs that rely on homeowners for system operation and maintenance. Educational initiatives 

are most effective when they result in understanding of the relationship between ground water 

and surface water, and how septic system siting, design, installation, operation, and maintenance 

can affect those resources and public health. Surveys show that many people have their septic 

tank pumped only after the system fails. Property owners who are educated in proper system 

operation and maintenance practices, and who understand the consequences of system failure, 

are more likely to take actions to ensure that their systems function properly. Typical public 

outreach and education program topics for homeowners in the present system of prescriptive and 

conventional on-site systems include: 

— How an on-site wastewater treatment system works; 

— System siting and design considerations; 

— How on-site systems can affect health, ground water, and surface water; 

— The importance of water conservation in minimizing hydraulic failures; 

— Practices to reduce mass pollutant loadings and toxic inputs to the system; 

— Typical operation and maintenance practices, procedures, and timetables; 

— How delaying septic tank pumpout can cause solids to clog infiltration systems; and 

— Costs of repairs, upgrades, or replacement of system components. 

Inventories of existing systems can be developed by consulting wastewater treatment plant 

service area maps, identifying areas not served by POTWs, and working with public and private 

6-41 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

utilities (drinking water, electricity, and septage pumpers and haulers) to develop a database of 

system owners and contact information. 

A variety of commercially available software exists for managing system inventory and other 

information. Electronic databases can make collecting, retrieving, using, and integrating data 

fairly easy after the initial implementation (data entry) and learning curve have been overcome. 

For example, if system locations are described in terms of specific latitude and longitude 

coordinates, a data layer for existing on-site systems can be created and overlaid on geographic 

information system (GIS) topographical maps. Adding information on on-site wastewater 

hydraulic output, estimated mass pollutant loads, and transport times expected for specified 

hydrogeomorphological conditions can help managers understand how water resources become 

contaminated. This can also help target remediation and prioritization actions to sources 

primarily responsible. Models can also be constructed to predict impacts from proposed 

development and suggest guidance on performance requirements for on-site systems in proposed 

development areas. 

6.3.2.2 Management, operation, and maintenance policies 

There are three basic approaches for developing and implementing a management program (see 

below). In addition, EPA has issued the EPA Voluntary National Guidelines for Management of 

Onsite and Clustered (Decentralized) Wastewater Treatment Systems (USEPA 2003). See 

http://cfpub.epa.gov/owm/septic/home.cfm for management guidelines, technology fact sheets, 

links, and other information). The guidelines describe five progressive tiers of management in 

the form of model programs that can be tailored by local communities to meet their public health 

and water resource protection needs (Table 6.10). Appropriate adoption of these guidelines based 

on level of risk and value of resources affected by on-site systems is strongly recommended. 

Table 6.11 shows an example matrix of different on-site system management program elements 

and functional responsibilities. 

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Management Measure 6: New and Existing On-Site Wastewater Treatment Systems 

Table 6.10: Guidelines for OWTS management programs under a tiered approach 

(adapted from USEPA, 2002a). 

Program type Program objectives Basic management program elements 

System inventory 

and awareness of 

operation and 

maintenance 

needs 

— Owner awareness of permitting 

program, installation, and operation and 

maintenance needs 

— Compliance with codes and regulations 

— Only conventional systems allowed 

— Prescriptive design and site requirements 

— Owner education to promote operation 

and maintenance 

— Complaint inspections and investigations 

— Point-of-sale inspections 

Management 

through 

maintenance 

contracts 

— Maintain prescriptive program for sites 

that meet siting criteria 

— Permit proven alternative systems on 

sites not meeting criteria 

— Prescriptive design/site requirements 

— Measurable operation and maintenance 

requirements 

— Allowances for approved alternatives 

— Operation and maintenance contracts for 

alternative systems 

— Inspections, owner education 

Operating permits — System design based on site conditions 

and performance requirements 

— System performance verified through 

permit renewal inspections 

— Wide variety of designs allowed 

— Performance governs acceptability 

— Compliance monitoring essential 

— Property sale or change of use triggers 

compliance assurance inspection 

Management 

entity operation 

and maintenance 

Public or private entity assumes operation 

and maintenance responsibilities for all 

systems in management area 

— Performance governs acceptability 

— Operating permits ensure compliance 

— All systems are inspected regularly 

— Monthly/yearly fees support program 

— Owner relieved of operation and 

maintenance responsibility 

Management 

entity ownership 

— Public or private entity owns and 

operates all systems in management 

area 

— Similar to centralized sewage treatment 

service approach 

— Performance governs acceptability 

— Operating permits ensure compliance 

— All systems are inspected regularly 

— Monthly/yearly fees support program 

— Management entity responsible for 

operation and maintenance 

— Management entity finances installation, 

repairs

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Table 6.11: Program elements and functional responsibilities example matrix. 

Program Element Responsible Party Comments 

Planning 

Stakeholder involvement process 

Watershed assessments 

Sensitive area and critical area designations 

Performance Requirements 

Health and environmental goals 

General requirements 

Requirements for sensitive and critical areas 

Site Evaluation 

Wastewater characterization procedures 

Site suitability analysis 

Design 

Prescriptive or performance criteria 

Design review and approval process 

Construction 

Permitting requirements and process 

Construction and/or installation oversight 

Operation and Maintenance 

Owner/operator requirements 

Performance certification approaches 

Residuals Management 

Residuals removal/disposal requirements 

Tracking and reporting system 

Certification and Licensing 

Staff and service providers covered 

Certification/licensing requirements 

Education and Training 

System owner/operator education 

Requirements for staff and service providers 

Provision of training programs 

Inspections and Monitoring 

Routine (point-of-sale) and emergency inspections 

Targeted surface water and ground water monitoring 

Corrective Actions 

Compliance schedules and enforcement program 

Repair, upgrade, or replacement oversight 

Record Keeping and Reporting 

Existing and new systems inventory 

Tracking system for permits/inspection/maintenance 

Financial/administrative/program management 

Financial Assistance 

Funding source development 

Administration/management funding 

Installation and operation and maintenance assistance 

 State Health Department 

 State Water Agency 

• District/County/Local Health Department 

k County or Local Government Office 

– Local/Regional Planning Office 

— Utility District 

y System Owner 

g Private Contractor

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Management Measure 6: New and Existing On-Site Wastewater Treatment Systems 

6.3.2.2.1 Voluntary Management 

An effective voluntary program develops recommended guidelines and educational materials and 

distributes this information to the homeowner or system operator. Voluntary management 

programs are highly dependent on comprehensive, easy-to-understand educational materials and 

an aggressive outreach program that includes distribution of the materials, training workshops, 

and site visits to provide individual assistance. 

In 1997 the University of Minnesota Cooperative Extension Service published a guide for 

homeowners that incorporates important elements of an on-site training program. The guide is 

available online at http://www.extension.umn.edu/distribution/naturalresources/DD6583.html. 

Another equally useful guide can be found on the North Carolina Cooperative Extension Web 

site at http://ces.soil.ncsu.edu/soilscience/publications/Soilfacts/AG-439-22. 

6.3.2.2.2 Regulatory Management 

Under this approach, the regulatory authority—typically a district or local health department—

oversees and enforces an on-site program of system design, permitting, installation, operation, 

and maintenance authorized under state and local codes. The codes may require routine 

inspections by the health officer either on an annual basis or at the time of property transfer, as is 

The permit is issued for a limited term, typically 5 years. Renewal requires that the owner document 

that the permit requirements have been met. If documentation is not provided, a temporary permit is 

issued with a compliance schedule. If the compliance schedule is not met, the county has the option of 

reissuing the temporary permit and/or assessing penalties. The permit program is self-supporting 

through permit fees. 

— System (technology) description. 

— Description of environmental conditions. 

— Site evaluation documentation. 

— Performance requirements. 

— System design, construction plan, specifications, and construction drawings. 

— Maintenance requirements. 

— Monitoring requirements (frequency, protocol, and reporting). 

— Contingency plan to be implemented if the system fails to perform to requirements. 

— Enforcement and penalty provisions. 

St. Louis County, located in the northeastern region of Minnesota, extends from the southwestern tip 

of Lake Superior north to the Canadian border. The physical characteristics of the region are poorly 

suited for application of traditional on-site treatment systems. Many of the soils are very slowly 

permeable lacustrine clays, shallow to bedrock, and often near saturation. The existing state code 

restricts on-site systems to sites with permeable soils of sufficient unsaturated depths to maintain a 3-

foot separation distance to the saturated zone. The county has adopted performance requirements 

that can be followed in lieu of the prescriptive requirements where less than 3 feet of unsaturated, 

permeable soils exist. In such cases the county requires the owner to continuously demonstrate and 

certify that the system is meeting performance requirements. This is achieved through the issuance of 

renewable operating permits for all alternative treatment systems. The operating permit is based on 

evaluation of system performance rather than design prescription and includes the following: 

On-site System Operating Permits in St. Louis County, Minnesota

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

the case in Washtenaw County, Michigan (Washtenaw County, 1999), the Code of 

Massachusetts Regulations, and other state and local statutes. Financial incentives and 

disincentives usually aid compliance; these can vary from small fines for poor system 

maintenance to mandatory repairs if the wastewater treatment system is not functioning properly. 

Inspection fees can cover program costs. Some jurisdictions (e.g., Florida) issue renewable 

operating permits and/or ground water discharge permits to manage system operation and 

maintenance. These permits may require homeowners either to have a contract with an 

authorized inspection and maintenance contractor or to demonstrate that periodic inspection and 

maintenance procedures have been performed (Florida Statutes, 2001). Permits or inspection 

requirements for alternative systems, especially those with mechanical components, are 

recommended. 

6.3.2.2.3 Direct management 

Another option for managing and maintaining on-site systems is a management entity, typically a 

wastewater utility or district. From a regulatory standpoint, an OWTS management program can 

save both time and money by allowing a management entity to execute various management 

program tasks. Incorporating on-site systems into a local or regional wastewater management 

district, with the district responsible for system operation and maintenance, is a means to ensure 

that small wastewater systems in a designated area function properly and do not threaten ground 

water or surface water. State legislation to create wastewater management districts is sometimes 

required. Enabling legislation for special districts allows district personnel to enter private 

properties within the district for the purpose of inspecting, repairing, upgrading, or replacing onsite systems. Taxpayers in the proposed district often must vote to create the special district. 

The regulatory authority also may decide to perform these tasks and assume overall 

responsibility for managing the on-site systems in its jurisdiction. Health departments can serve 

as the management entity under some of the approaches outlined above because they often have 

considerable permitting, installation, and inspection authority. Regardless of the approach, 

system users usually pay an annual fee that is applied to operation, maintenance, and 

management costs. Texas law authorizes local governments to petition the Texas Natural 

Resource Conservation Commission to assume management authority for on-site systems (Texas 

Chippewa County is located on Michigan’s Upper Peninsula, along the shores of Lake Superior. Over 

the past 10 years, the number of requests for OWTS permits has tripled. The high demand for 

property in the county, as well as its increased value as a tourist destination, has dramatically 

increased the county’s population. Many of the properties to be developed are located in 

environmentally sensitive areas, including fractured bedrock and limestone, which puts the county’s 

ground water at high risk of contamination from faulty septic systems. 

The county’s Environmental Health Department amended the existing sanitary codes to allow the 

installation of alternative on-site systems for lakeshore areas. County officials worked with a Michigan 

State University professor to educate the citizens and local officials of Chippewa County about the 

values of these alternative systems. Some of these alternative systems include recirculating systems, 

single-pass filter systems, sewage waste lagoons, and mound systems. In the end, both the public 

and the local government supported the new codes, and no new bacterial contamination has been 

found since the codes were passed.

On-Site Sewage Management Ordinance, Chippewa County, Michigan

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Management Measure 6: New and Existing On-Site Wastewater Treatment Systems 

Administrative Code, 1997). Procedures that can be used to apply the wastewater management 

district concept to a specific problem area include: 

— Researching relevant legal and regulatory issues; 

— Conducting a thorough site investigation; 

— Identifying the specific geographic area to be included within the wastewater 

management district; 

— Selecting the performance standards to be met and the means of attaining them; 

— Preparing accurate cost estimates; 

— Receiving approval from ratepayers within the proposed district for the creation of the 

management district; 

— Preparing and adopting regulations, as needed, to establish the wastewater management 

district; and 

— Adopting a management strategy (including operational, administrative, and financial 

processes). 

Resources are available to help management entities explore the concept of an onsite wastewater 

management district. For example, the City of Austin, Texas, provides online resources related to 

its study of management district establishment (see http://www.ci.austin.tx.us/wri/altern.htm) 

6.3.2.3 Inspection and monitoring programs 

Inspection and monitoring programs are recommended to assess current and likely (future) onsite wastewater impacts. A means of inventorying existing and new systems, conducting 

inspections, providing monitoring data, or responding to treatment failures should be developed. 

As noted above, information on new systems (system owner, contact information, system type, 

location, design life and capacity, recommended service schedule) should be collected by the 

OWTS regulatory agency at the time of permitting and installation. Telephone, door-to-door, or 

mail surveys can be helpful to gather information on system type, tank capacity, installation date, 

last date of service (e.g., pumping, repair), problem incidents, and other relevant information. A 

number of private firms marketing new treatment technology packages (e.g., fixed film reactors, 

sand/media filters, aeration units) include remote monitoring services as part of the system 

package. For example, some companies install controls that continuously upload key system data 

(e.g., flow rates, pump cycles) to dedicated Web sites. Management staff can monitor the 

performance of multiple systems by accessing these Web sites, allowing detection of problems 

before massive failures occur. The per-unit cost of remote monitoring, which is required under 

the system installation contract, can range from $25 to $50 or more, depending on the type of 

unit and maintenance needs. The extra expense for necessary equipment is typically less than 

10 percent of the cost of the packaged system. 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

6.3.2.3.1 System inspections 

On-site system operation and performance inspections should check for the following (USEPA, 

2002a): 

— Evidence of vehicles being driven over the septic tank or reserve field; 

— Installation of pavement, driveways, or structures over the septic tank or reserve field; 

— Wet areas or poor drainage in or around the infiltration field; 

— Slow flushing or gurgling of water in plumbing fixtures; 

— Leaking toilets or addition of significant wastewater-generating fixtures such as water 

softeners; 

— Additions to the house or building after system installation; 

— Surface drainage patterns in the area of the tank and infiltration field; 

— Broken or open tank access covers or doors; and 

— Sludge or scum buildup in the septic tank; clogging of tank filters (if present). 

More-detailed inspections of the system are recommended if there is evidence of a problem and 

should include the following: 

— Pump and inspect the tank for structural deficiencies. 

— Inspect the pumping components of the system. 

— Test the system by filling the tank and observing the water level rise and fall. 

— Inspect the baffles, valves, or other key appurtenances. 

— Check all piping from the fixtures to the tank. 

— Inspect runoff pathways of water from roofs, driveways, and other sources. 

— Uncover distribution boxes (if used), and check flow distribution. 

— Check for plumbing fixture leaks. 

Inspections can be conducted in several ways (USEPA, 1993b). Homeowners can serve as 

monitors if they are educated and trained on how to inspect their own systems; however, this 

approach has not been effective in most cases. Brochures are often made available to instruct 

individuals on how to monitor their systems and the steps to take if they determine that their onsite system is not functioning properly. It should be noted, however, that homeowners rarely 

inspect their own systems, even with training. Trained inspectors are the best means for 

identifying failing systems. 

Inspections can be conducted at the time of property transfer (point-of-sale inspections). 

Massachusetts has a rule that has required regular inspections since 1995. Colorado mandates 

inspections at the time of transfer, although its inspection requirements are less stringent than 

those of other states. Inspections are discussed further in EPA Voluntary National Guidelines for 

6-48 
Management Measure 6: New and Existing On-Site Wastewater Treatment Systems 

Comprehensive Monitoring and Inspection Program in Nags Head

The town of Nags Head has implemented a program to identify and address on-site system impacts in 

that North Carolina Outer Banks community. The town’s Septic Health Initiative Program secured 

competitive bids for tank pumping and inspection and will reimburse full inspection costs (about $65) 

and provide a $30 rebate on the next water bill if the system owner has the tank pumped. Monitoring 

consists of a series of ground water well and surface sites that are tested for fecal coliform, ammonia, 

dissolved oxygen, nitrate, pH, salinity, phosphorus, specific conductance, and turbidity. An education 

program complements the effort by circulating information on treatment processes, operation, and 

maintenance (Krafft, 2001).

Management of Onsite/Decentralized Wastewater Treatment Systems 

(http://cfpub.epa.gov/owm/septic/home.cfm). 

Inspection programs operated by OWTS management agencies, special districts, and utilities can 

be the most effective in terms of cost and results. The State of Arizona requires routine operation 

and maintenance inspections for alternative on-site systems and pre-sale inspections (NSFC, 

1995). Massachusetts requires inspections by a certified individual at the time of property 

transfer. Minnesota requires property transfers to be accompanied by certification that the on-site 

system is performing in a satisfactory manner. More than half of all Minnesota counties and most 

lending entities require inspections because of market-driven desires to ensure that on-site 

systems are operating properly at the time of property sale (Prager, 2000). Massachusetts also 

requires that systems with a design flow of 10,000 gal/day or more be inspected every three 

years, and shared facilities must be inspected annually (Massachusetts Department of 

Environmental Protection, 1996). Some counties (e.g., Washtenaw County, Michigan) with 

mandatory property transfer inspection programs require inspectors to be certified. New 

Hampshire requires an assessment and an on-site system inspection by a permitted designer prior 

to the sale of any developed waterfront property (New Hampshire Code of Administrative Rules, 

2001). 

States and localities can also indirectly assess whether on-site systems are failing through surface 

water and ground water monitoring. If indicator pollutants (e.g., fecal coliform as an indicator of 

potential pathogen contamination) are found, nearby on-site systems should be inspected to 

determine if they are a contributing or primary source of the contaminants. For example, 

residents living along the shore of Ten Mile Lake in Minnesota support a lake association that 

conducts regular fecal coliform monitoring below lakefront homes. High coliform concentrations 

prompt system inspections and involvement of property owners in remediation discussions. 

Owners who repair their system or install a new one are added to the OWTS “honor roll,” which 

is published in the association’s monthly newsletter. 

Health department personnel and/or system inspectors often use tracer dye to observe effluent 

movement (USEPA, 1991). Many local agencies use non-toxic tracer dye to determine 

wastewater migration into nearby wells or surface waters. Tracer dye, which is typically flushed 

down the toilet, is often used to demonstrate to system owners that effluent is migrating rapidly 

into nearby surface waters or ground water. Rapid movement of effluent, that is, 20 to 30 feet in 

less than 30 minutes, may indicate that subsurface infiltration and treatment of wastewater have 

been short-circuited. Other confirmatory tests should be employed to verify this fact. 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Galveston Bay Project Targets “Hot Spots”

In support of the Galveston Bay Estuary Program, the Galveston county health department conducted 

an intensive survey of on-site systems in the Dickinson Bayou watershed to identify failed systems 

and improve homeowner operation of existing systems. During the first part of the project, 36 of 90 (40 

percent) systems inspected exhibited some degree of failure and were likely contributing to significant 

fecal coliform water quality violations in the bayou (Galveston County Health District, 1998).

A variety of online resources are available for agencies seeking information on the operation, 

maintenance, or inspection of on-site systems. The Rhode Island Department of Environmental 

Management published the Septic System Checkup inspection guide in 2000 and posted an online 

version at http://www.dem.ri.gov/pubs/regs/regs/water/isdsbook.pdf. A general operation and 

maintenance manual entitled The Septic System Owner’s Guide is available online from the 

University of Minnesota Extension Service at 

http://www.extension.umn.edu/distribution/naturalresources/DD6583.html. For links to other 

online resources, visit the links page maintained by the Consortium of Institutes for 

Decentralized Wastewater Treatment at http://www.onsiteconsortium.org/links.cfm. The Wayne 

County, Ohio, Health District also has an extensive list of links on its Web site 

(http://wchd.neobright.net/wc_wastewater_tx2.html). 

6.3.2.3.2 Improving system effectiveness through water conservation and pollutant reduction 

In addition to structural methods to remove nitrogen and other pollutants from wastewater, 

management practices that reduce wastewater flow and/or pollutants are effective. Reducing the 

overall hydraulic load by installing water-saving devices and adopting water conservation 

practices can increase the residence times for wastewater pretreatment and, most importantly, 

reduce the amount of wastewater that must be infiltrated into the soil. Jarrett et al. (1985) stated 

that 75 percent of soil absorption field failures could be attributed to hydraulic overloading. 

Several practices are available to retrofit these failing systems so that they operate properly. 

Eliminating the use of garbage disposals (pollutant reduction), installing low-volume plumbing 

fixtures (flow reduction), and adopting water conservation practices (flow reduction) are usually 

the most cost-effective approaches for reducing pollutant and hydraulic loads to the field. 

Reduced loading of organics and chemicals can extend the useful life of the on-site system and 

improve treatment effectiveness. Mass pollutant loads in the OWTS can be significantly 

decreased by avoiding detergents that contain phosphates, cleaning food debris and grease from 

dishes before washing, removing or not using in-sink garbage disposal units, and eliminating the 

disposal of sanitary napkins and disposable diapers in toilets. Inputs of discarded antibiotics, 

dialysis unit discharges, and toxic cleaners and other chemicals can cause treatment process 

upsets and may impact public health if they reach the ground water. These problems can be 

addressed through homeowner education and better disposal practices. See Management 

Measure 9 (Pollution Prevention) for more information about proper disposal practices. 

Reducing hydraulic loads can achieve significant reductions in OWTS failure rates. In 1992 

Congress adopted the Energy Policy Act, which established national standards governing water 

use and energy conservation for showers, kitchen sinks, basins, and toilets (see Table 6.12). 

Several states have implemented specific water conservation practices (USEPA, 1998b). If lowflow plumbing fixtures are used, it is important that on-site system design not be modified to 

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Management Measure 6: New and Existing On-Site Wastewater Treatment Systems 

decrease the required septic tank size. The use of smaller septic tanks could negate the 

advantages of using low-flow plumbing fixtures by increasing organic loading rates to the soil 

infiltrative surface. 

Table 6.12: Comparison of current and federally mandated flow rates and flush volumes 

(USEPA, 1998b). 

Fixture Current Practice 

Energy Policy Act of 

October 1992 

Potential reduction in 

water used (%) 

Kitchen Sink 3.0 gpm 2.5 gpm 17 

Lavatory 3.0 gpm 2.5 gpm 17 

Shower 3.5 gpm 2.5 gpm 29 

Tub 6.0 gpm 4.0 gpm 33 

Water closet (tank) 3.5 gal 1.6 gal 54 

Water closet (valve) 3.5 gal 1.6 gal 54 

Urinal 3.0 gal 1.5 gal 50

Eliminating the use of garbage disposals can significantly reduce the loading of suspended solids 

and BOD to OWTSs (Table 6.13) unless OWTSs are designed for their use. Eliminating garbage 

disposals can decrease the buildup of solids in the septic tank and reduce the frequency of 

pumping required. A number of states have regulations prohibiting the installation of garbage 

disposals where on-site systems are used. New OWTSs can be designed to accommodate 

garbage disposals and the associated increase in organic and solids loadings to wastewater by 

increasing tank volume or pumping frequency (USEPA, 2001c). 

Table 6.13: Residential wastewater pollutant contributions by source (adapted from 

USEPA, 1992b). 

Parameter 

Garbage 

disposal (gpcd) Toilet (gpcd) 

Bathing, sinks, 

appliances (gpcd) 

Approximate 

total (gpcd) 

BOD5 Mean 

Range 

% of total 

18.0 

10.9–30.9 

(28%) 

16.7 

6.9–23.6 

(26%) 

28.5 

24.5–38.8 

(45%) 

63.2 

– 

(100%) 

TSS Mean 

Range 

% of total 

26.5 

15.8–43.6 

(37%) 

27.0 

12.5–36.5 

(38%) 

17.2 

10.8–22.6 

(24%) 

70.7 

– 

(100%) 

Nitrogen Mean 

Range 

% of total 

0.6 

0.2–0.9 

(5%) 

8.7 

4.1–16.8 

(78%) 

1.9 

1.1–2.0 

(17%) 

11.2 

– 

(100%) 

Phosphorus Mean 

Range 

% of total 

0.1 

– 

(4%) 

1.6 

– 

(59%) 

1.0 

– 

(37%) 

2.7 

– 

(100%)

6.3.2.4 Management of residuals to ensure that they do not present significant risks to 

human health or water resources 

On-site systems are not maintenance-free systems. Huang (1983) stated that half of on-site 

system failures are due to poor operation and maintenance. Most residential septic tanks are 

designed for approximately 72- to 96-hour retention of wastewater to allow for the removal of 

solids, greases, and fats. Some of the solids retained in the tank decompose naturally by bacterial 

and chemical action. As sludge accumulates on the bottom of the tank, however, the decrease in 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

tank volume available for storing settleable solids and raw wastewater results in less contact 

time. When sludge or scum levels get too near the outlet entrance level, solids can move directly 

to the soil absorption system and cause clogging (Mancl and Magette, 1991). Septic tank effluent 

screens can provide some protection from neutrally buoyant solids and during tank upsets, but 

periodic removal of solids from the tank is necessary to protect the soil absorption system. Most 

tanks should be pumped out every three to five years in lieu of a regular inspection program. If a 

septic system is not pumped out regularly, failure will not occur immediately; however, 

continued neglect will cause the SWIS to fail because it is no longer protected from greases, oils, 

and solids. Failure may require replacement, often at considerable expense. 

Responsibility for ensuring proper operation and maintenance is most often left to homeowners. 

Homeowners generally are not properly trained or informed on how to take care of their systems, 

and many do not care to do so. On-site system regulatory authorities and management entities 

have recognized the need for more comprehensive management programs and have developed 

educational and other programs to help owners understand their responsibility for system 

management. Some regulatory authorities have opted for a more proactive approach and have 

developed inspection programs, renewable permits, and financial incentives (e.g., low-interest 

loans, grants) for installing, upgrading, or repairing underperforming systems. More than 100 

OWTS management programs that provide operational oversight beyond initial permitting are 

now operating across the country (Knowles, G., Coordinator, National Onsite Demonstration 

Program (NODP) Phase IV, personal communication, 2000; see also 

http://www.nodp.wvu.edu/). 

The primary objective of a residuals management program is to establish procedures and rules 

for handling and disposing of accumulated sludge and wastewater removed from tanks (i.e., 

septage, also called biosolids) in an affordable manner that protects public health and ecological 

resources. When planning a program, it is important to have a thorough knowledge of legal and 

regulatory requirements regarding handling and disposal. In general, state and local septage 

management programs that incorporate land application or disposal to landfills must comply with 

Subpart C of 40 CFR (U.S. Code of Federal Regulations) Part 503. Detailed guidance for 

identifying, selecting, developing, and operating reuse or disposal sites for septage can be found 

in the two process design manuals: Land Application of Sewage Sludge and Domestic Septage 

and Surface Disposal of Sewage Sludge and Domestic Septage (USEPA, 1995 a and b), which 

are posted on the Internet at http://www.epa.gov/ORD/WebPubs/sludge.pdf. Additional 

information can be found in Domestic Septage Regulatory Guidance (USEPA, 1993a). 

States and municipalities typically establish additional public health and environmental 

protection regulations for residuals handling, transport, treatment, and reuse or disposal. In 

addition to regulations, practical limitations such as land availability, site conditions, buffer zone 

requirements, hauling distances, fuel costs, and labor costs play a major role in evaluating 

septage reuse or disposal options. These options generally fall into three basic categories: land 

application; treatment at a wastewater treatment plant; or treatment at a special septage treatment 

facility. Initial steps in the residuals reuse or disposal decision-making process include 

characterizing the quality and quantity of the septage to be produced annually and determining 

potential adverse impacts associated with various reuse or disposal scenarios. In general, 

program officials strive to minimize the exposure of humans, animals, ground water, and surface 

water to potentially toxic or hazardous chemicals and pathogenic organisms found in septage. 

6-52 
Management Measure 6: New and Existing On-Site Wastewater Treatment Systems 

Other key aspects of residuals management programs are tracking or manifest systems that 

identify septage sources, pumpers, transport equipment, final destination, and treatment, along 

with procedures such as vector control, wet weather runoff, and access to disposal sites for 

controlling human exposure to residuals. 

6-53 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

6.4 Information Resources 

The Onsite Wastewater Treatment System Manual (EPA, 2002a) is an update to EPA's 1980 

manual entitled Design Manual: Onsite Wastewater Treatment and Disposal Systems. This 

comprehensive reference manual is designed to provide state and local governments with 

guidance on the planning, design, and oversight of onsite systems. This manual will also be 

useful for onsite wastewater professionals, developers, land planners, and academics. It is 

available in PDF format from 

http://www.epa.gov/ORD/NRMRL/Pubs/625R00008/625R00008.htm. 

EPA Voluntary National Guidelines for Management of Onsite/Decentralized Wastewater 

Treatment Systems is a set of recommended practices needed to raise the level of performance of 

on-site/decentralized wastewater systems through improved management programs. Five model 

programs are presented as a progressive series: (1) system inventory and awareness of 

maintenance needs; (2) management through maintenance contracts; (3) management through 

operating permits; (4) operation and maintenance by a public or private management entity; and 

(5) ownership and management by a public or private management entity. Each of these model 

programs includes a set of recommended approaches for planning, siting, design, performance, 

installation, operation, maintenance, and monitoring of wastewater systems. The guidelines can 

be obtained at EPA’s Office of Wastewater Management Web site at 

http://cfpub.epa.gov/owm/septic/home.cfm. 

Funded by the U.S. Environmental Protection Agency, the National Small Flows Clearinghouse 

(NSFC) helps small communities and individuals find affordable wastewater treatment options to 

protect public health and the environment. The NSFC Web site, which can be accessed at 

http://www.nesc.wvu.edu/nsfc/nsfc_index.htm, offers news, publications, databases, discussion 

groups, information about innovative and alternative wastewater technology projects (through 

EPA's Environmental Technology Initiative project), and links related to small wastewater 

systems. 

The ASTM International Web site (http://www.astm.com/) offers guides to standard practices 

and technical publications on environmental assessment and waste management practices that 

can be useful for siting, designing, and installing OWTSs. 

The American Society of Agricultural Engineers (ASAE) offers several proceedings from 

conferences focusing on on-site wastewater treatment at its publications page 

(http://www.asabe.org/pubs/PubCat02/waste.html). ASAE also has a searchable library of 

technical articles (http://asae.frymulti.com/), many of which pertain to OWTSs. 

The National Onsite Wastewater Recycling Association (NOWRA) Web site, which can be 

accessed at http://www.nowra.org/, offers a calendar of events related to OWTSs, contact 

information for state and local OWTS organizations, links to OWTS-related businesses and 

organizations, the Onsite Insight newsletter, technical guidance for owners and operators of 

OWTSs, a bookstore with conference proceedings available for purchase, and the Model 

Framework for Unsewered Wastewater Infrastructure, which is a guide for establishing future 

national policy for onsite systems. 

6-54 
Management Measure 6: New and Existing On-Site Wastewater Treatment Systems 

6.5 References 

Alaska Administrative Code. 1999. Title 18 (Environmental Conservation), Chapter 72, Article 

1. Alaska Department of Environmental Conservation. April 1999 version. 

Aller, L., T. Bennett, J. Lehr, R. Petty, and G. Hackett. 1987. DRASTIC: A Standardized System 

for Evaluating Ground Water Pollution Potential Using Hydrogeologic Settings. U.S. 

Environmental Protection Agency, Ada, OK. 

American Society for Testing and Materials (ASTM). 1995. Standard Practice for Surface Site 

Characterization for On-Site Septic Systems. Practice D5879-95e1. American Society for 

Testing and Materials, Conshohocken, PA. 

American Society for Testing and Materials (ASTM). 1996a. Standard Practice for Preliminary 

Sizing and Delineation of Soil Absorption Field Areas for On-Site Septic Systems. 

Practice D5925-96e1. American Society for Testing and Materials, Conshohocken, PA. 

American Society for Testing and Materials (ASTM). 1996b. Standard Practice for Subsurface 

Site Characterization of Test Pits for On-Site Septic Systems. Practice D5921-96e1. 

American Society for Testing and Materials, Conshohocken, PA. 

Bicki, J.T., and R.B. Brown. 1991. On-site sewage disposal: the influence of system density on 

water quality. Journal of Environmental Health 53:39–42. 

Boyle, W. 1995. Nitrogen Removal from Domestic Wastewater in Unsewered Areas. University 

of Washington, Seattle, WA. 

Bruen, M.G., and R.J. Piluk. 1994. Performance and costs of on-site recirculating sand filters. In 

On-Site Wastewater Treatment: Proceedings of the Seventh International Symposium on 

Individual and Small Community Sewage Systems. American Society of Agricultural 

Engineers, Atlanta, GA, December 11–13, 1994. 

Caudill, J.R. 1998. Homeowner Education about Onsite Sewage Systems. In Proceedings of the 

7th National Onsite Wastewater Recycling Association and Annual Conference, Northern 

Kentucky, October 1998. Laurel, MD. 

Center for Infrastructure Research. No date. Drinking Water and Wastewater Treatment: 

Research Advancements. University of Nebraska, Center for Infrastructure Research, 

Omaha, NE. 

http://www.unomaha.edu/~wwwcir/publications/advancements/treatment2.htm. 

Code of Maryland Regulations. 2001. Non-Conventional On-Site Sewage Disposal Systems. 

COMAR 26.04.02.06. http://www.dsd.state.md.us/comar/26/26.04.02.06.htm. Accessed 

January 14, 2001. 

6-55 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Code of Massachusetts Regulations. 2001. Part I, Title IX, Chapter 62, Taxation of Income; 

Section 6: Credits. http://www.state.ma.us/legis/laws/mgl/62%2D6.htm. Accessed 

January 15, 2002. 

Commonwealth Biomonitoring. 2001. Indian Lakes Improvement Project: A Lake and River 

Enhancement Project funded by the Indiana Department of Natural Resources Division 

of Soil Conservation. 

http://www.state.in.us/dnr/soilcons/dreamweaver/images/fivelake.pdf. Indianapolis, IN. 

Converse, J.C., and E.J. Tyler. 2000. Wisconsin Mound Soil Absorption System: Siting, Design, 

and Construction Manual. Small Scale Waste Management Project. University of 

Wisconsin-Madison, Madison, WI. 

Dickey, E.C., and P.W. Harlan. 1996. Soils, Absorption Fields and Percolation Tests for Home 

Sewage Treatment. NebGuide. University of Nebraska Cooperative Extension, Lincoln, 

NE. http://www.ianr.unl.edu/pubs/wastemgt/g514.htm. Last updated November 1996. 

Accessed July 17, 2000. 

Dickey, E.C., P.W. Harlan, and G. Hosek. 1996. A Septic Tank System for Sewage Treatment. 

NebGuide. University of Nebraska Cooperative Extension, Lincoln, NE. 

http://www.ianr.unl.edu/pubs/wastemgt/g448.htm. Last updated November 1996. 

Accessed July 17, 2000. 

Eliasson, J.M., D.A. Lenning, and S.C. Wecker. 2001. Critical Point Monitoring: A New 

Framework for Monitoring On-Site Wastewater Systems. In Onsite Wastewater 

Treatment: Proceedings of the Ninth National Symposium on Individual and Small 

Community Sewage Systems. American Society of Agricultural Engineers, St. Joseph, 

MI. 

Florida Department of Health and Rehabilitative Services. 1993. Onsite Sewage Disposal System 

Research in Florida: An Evaluation of Current OSDS Practices in Florida. Prepared for 

Florida Department of Health and Rehabilitative Services, Tallahassee, FL, by Ayres 

Associates, Eau Claire, WI. 

Florida Statutes. 2001. Title XXIX, Public Health; Chapter 381, General Provisions; Section 

0065, Onsite Sewage Treatment and Disposal Systems; Regulations; Subjection 4(j) 

Permits, Installation, and Conditions. 

Fobbs, M., and M. Skala. 1992. Waterborne hepatitis A associated with a church and school. 

Missouri Epidemiologist 14(5). 

Galveston County Health District. 1998. Voluntary Inspection and Information Assistance 

Program to Reduce Bacterial Pollution Caused by Malfunctioning Septic Systems in 

Dickinson Bayou. www.gchd.org/pages/ech/tocfr.html. Accessed January 15, 2002. 

Hagedorn, C. 2000. Bacterial Source Tracking (BST). www.bsi.vt.edu/biol_4684/BST/BST.html. 

Accessed January 15, 2002. 

6-56 
Management Measure 6: New and Existing On-Site Wastewater Treatment Systems 

Harmeson, R.H., R.W. Solio, and T.E. Larson. 1971. The nitrate situation in Illinois. Journal of 

the American Water Works Association 63:303–310. 

Hoover, M.T. 1997. A Framework for Site Evaluation, Design, and Engineering of On-Site 

Technologies Within a Management Context. Marine Studies Consortium and ad hoc 

Task Force for Decentralized Wastewater Management, Chestnut Hill, MA, and Waquoit 

Bay National Estuarine Research Reserve, Waquoit, MA. 

Hoover, M.T., T.M. Disy, M.A. Pfeiffer, N. Dudley, R.B. Meyer, and B. Buffington. 1996. North 

Carolina Subsurface Operators Training School Manual. Soil Science Department, 

College of Agriculture and Life Sciences, North Carolina State University, Raleigh, NC, 

and North Carolina Department of Environment, Health, and Natural Resources, Raleigh, 

NC. 

Huang, J.Y.C. 1983. Management of on-site disposal systems: Case study. Journal of 

Environmental Engineering 109(4):845-858. 

Krafft, T. 2001, February 8. E-mail to Decentralized Wastewater Management Listserver, U.S. 

Environmental Protection Agency, Office of Wastewater Management, Washington, DC. 

Kreissl, J. 1982. Evolution of State Codes and Their Implications. In Proceedings of 4th 

Northwest On-Site Wastewater Disposal Short Course, University of Washington, 

Seattle, WA, September 1982. 

Leyden, K. 1999, November 5. Letter to Joelle Gore, Office of Ocean and Coastal Resource 

Management, regarding Maine’s 6217 Program (On-Site Disposal Systems). 

Lockwood, K. 1997. Septic Systems—An Engineer’s View. Lockwood, Dietershagen Associates, 

Clifton Park, NY. www.inspect-ny.com/septic/lockwood.htm. Last updated August 7, 

1997. Accessed July 17, 2000. 

Loudon, T.L. 1996. Performance of Trenches Receiving Sand Filter Effluent in Slowly 

Permeable Soils. Sand Filter Information Package # WWPCGN29. National Small Flows 

Clearinghouse, West Virginia University, Morgantown, WV. 

Maine Department of Human Services. 1996. Rules for Site Evaluators of Subsurface 

Wastewater Disposal Systems. Statutory Authority: 22 MRSA Section 42 Sub-section 

3A. 10-144 Chapter 245. 

Mancl, K., and W. Magette. 1991. Maintaining Your Septic Tank. Publication WR28. University 

of Maryland Cooperative Extension Service, College Park, MD. 

Martin, D. 1999. Chippewa County On-Site Sewage Management. Chippewa County 

Environmental Health Department, Chippewa, MI. www.gem.msu.edu/casestd/ 

chippewa.html. Last updated April 15, 1999. Accessed July 17, 2000. 

6-57 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Maryland Department of the Environment. 2000. Septic System Advisory Committee Final 

Report. www.mde.state.md.us/environment/septic/septic-report2.pdf. Last updated 

February 25, 2000. Accessed July 17, 2000. 

Massachusetts Department of Environmental Protection. 1996. 310 CMR 15.000: The State 

Environmental Code, Title 5: Standard Requirements for the Siting, Construction, 

Inspection, Upgrade and Expansion of On-Site Sewage Treatment and Disposal Systems 

and For the Transport and Disposal of Septage. www.state.ma.us/dep/brp/files/ 

310cmr15.pdf. Last updated December 27, 1996. Accessed January 15, 2002. 

National Oceanic and Atmospheric Administration (NOAA). 1995. National Shellfish Register. 

National Oceanic and Atmospheric Administration, Washington, DC. 

National Small Flows Clearinghouse (NSFC). 1995. Summary of Onsite Systems in the United 

States: 1993. National Small Flows Clearinghouse, Morgantown, WV. 

National Small Flows Clearinghouse (NSFC). 1997. Management Districts Technology Package. 

Document WWBKGN70. National Small Flows Clearinghouse, Morgantown, WV. 

National Small Flows Clearinghouse (NSFC). 1998. Environmental Technology Initiative Fact 

Sheets. OWTS Technical Overviews. National Small Flows Clearinghouse, Morgantown 

WV. 

Nelson, Dix, and Shephard. 1999. Unpublished draft. Survey reference and paper from 

RF/Parsons Engineering Science/National Small Flows Clearinghouse. 

New Hampshire Code of Administrative Rules. 2001. Part Env-WS: Waterfront Property Site 

Assessment Study. Env-Ws 1025.01. Concord, NH. 

Noah, M. 2000. Mandated certification of onsite professionals. Small Flows Quarterly 1(1). 

North Carolina Department of Environment, Health, and Natural Resources (NC DEHNR). 

1996. Onsite Wastewater Management Guidance Manual. North Carolina Department of 

Environment, Health, and Natural Resources, Division of Environmental Health, Onsite 

Wastewater Section, Raleigh, NC. 

NSF International. 2000. NSF International Onsite Wastewater Inspector Accreditation 

Program. NSF International, Ann Arbor, MI. 

Ohio State University. No date. Septic Tank—Mound System. Fact Sheet AEX-744. Ohio State 

University, Department of Food, Agricultural, and Biological Engineering, Columbus, 

OH. 

Otis, R.J. and D.L. Anderson. 1994. Coming of Age: Onsite Wastewater Treatment System 

Management. In Proceedings of the Wastewater Nutrient Removal Technology and 

Onsite Management Districts Conferences. Waterloo, ON: Waterloo Center for 

Groundwater Research, University of Waterloo, pp. 97–109. 

6-58 
Management Measure 6: New and Existing On-Site Wastewater Treatment Systems 

Parsons Engineering Science. 2000. Septic System Failure Summary. Prepared for U.S. 

Environmental Protection Agency, Office of Wastewater Management, Washington, DC, 

by Parsons Engineering Science, Fairfax, VA. 

Prager, J. 2000. E-mail to State Regulators Listserver, National Small Flows Clearinghouse, 

Morgantown, WV. Responses summarized by Mark Soltman on August 8, 2000. 

Purdue University, 2000. Constructed Wetlands Diagrams. 

http://abe.www.ecn.purdue.edu/~epados/septics/images/fig5.gif. Accessed July 17, 2000. 

Roy, C., and J.P. Dube. 1994. A recirculating gravel filter for cold climates. In On-Site 

Wastewater Treatment: Proceedings of the Seventh International Symposium on 

Individual and Small Community Sewage Systems, American Society of Agricultural 

Engineers, Atlanta, GA, December 11–13, 1994. 

Schaub, F. 2000. E-mail to State Regulators Listserver on November 2, 2000. Frank Schaub, 

Connecticut Department of Public Health, Supervising Sanitary Engineer, Environmental 

Engineering Section. 

Shephard, F.C. 1996. Managing Wastewater: Prospects in Massachusetts for a Decentralized 

Approach. A Discussion of Options and Requirements. Prepared for the Ad Hoc Task 

Force for Decentralized Wastewater Management by the Waquoit Bay National Estuarine 

Research Reserve, Waquoit, MA. 

Siegrist, R.L. 2001. Advancing the science and engineering of onsite wastewater systems. In OnSite Wastewater: Proceedings of the Ninth National Symposium on Individual and Small 

Community Sewage Systems, American Society of Agricultural Engineers, Fort Worth, 

TX, March 11–14, 2001. 

Siegrist, R.L., E.J. Tyler, and P.D. Jenssen. 2000. Design and performance of onsite wastewater 

soil absorption systems. In Proceedings of the Decentralized Wastewater Management 

Research Needs Conference, Washington University, St. Louis, MO, May 19–20, 2000. 

South Carolina Department of Health and Environmental Control. 1999. A Technical Evaluation 

of Onsite Wastewater Disposal in South Carolina. Prepared by the Onsite Wastewater 

Technical Committee in January 1999. 

Stein, O.B., J.A. Biederman, P.B. Hook, and W.C. Allen. 1998. Performance data from model 

constructed wetlands for wastewater treatment. In Engineering Approaches to Ecosystem 

Restoration: Proceedings of the 1998 Wetlands Engineering and River Restoration 

Conference, American Society of Civil Engineers, Denver, CO, March 22–27, 1998. 

Stuart, K. 2000. E-mail to the State Regulators Listserver on October 31, 2000. Ken Stuart, 

Director, Contra Costa Environmental Health Department, Concord, CA. 

Tchobanoglous, G., and F.L. Burton. 1991. Wastewater Engineering, Treatment, Disposal and 

Reuse. McGraw-Hill Publishing Company, New York, NY. 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Tetra Tech, Inc. 2000. Application of the Patuxent River Septic System Nitrogen Loading Tool. 

Prepared for Prince George’s County, MD, by Tetra Tech, Inc., Laurel, MD. 

Texas Administrative Code. 1997. Onsite Sewage Facilities. Title 30, Chapter 285. Adopted 

February 5, 1997. 

Tyler, E.J., W.C. Boyle, J.C. Converse, R.L. Siegrist, D.L. Hargett, and M.R. Schoenemann. 

1985. Design and Management of Subsurface Soil Absorption Systems. EPA-600-2-85-

070. U.S. Environmental Protection Agency, Water Engineering Research Laboratory, 

Cincinnati, OH. 

U.S. Census Bureau. 1997a. American Housing Survey for the United States: 1997—Table 2-6. 

Detailed Tables for Total Occupied Housing Units—What Went Wrong? 

http://www.census.gov/hhes/www/housing/ahs/97dtchrt/tab2-6.html. Last updated 

September 14, 2000. Accessed January 16, 2002. 

U.S. Census Bureau. 1997b. American Housing Survey for the United States: 1997—Table 2-4. 

Selected Equipment and Plumbing: Occupied Units. 

http://www.census.gov/hhes/www/housing/ahs/ahs97/tab24.html. Last updated 

December 13, 2000. Accessed October 30, 2001. 

U.S. Census Bureau. 1999. Historical Census of Housing Tables: Sewage Disposal. 

http://www.census.gov/hhes/www/housing/census/historic/sewage.html. Last updated 

December 15, 2000. Accessed January 16, 2002. 

U.S. Environmental Protection Agency (USEPA). 1980. Design Manual: Onsite Wastewater 

Treatment and Disposal Systems. EPA 625-1-80-012. U.S. Environmental Protection 

Agency, Office of Water, Washington, DC. 

U.S. Environmental Protection Agency (USEPA). 1991. A method for tracing on-site effluent 

from failing septic systems. Nonpoint Source News-Notes 12 (April/May). 

U.S. Environmental Protection Agency (USEPA). 1992. Wastewater Treatment/Disposal for 

Small Communities. EPA-625-R-92-005. U.S. Environmental Protection Agency, Office 

of Research and Development, Center for Environmental Research Information, 

Cincinnati, OH. 

U.S. Environmental Protection Agency (USEPA). 1993a. Domestic Septage Regulatory 

Guidance. EPA-832-B-92-005. U.S. Environmental Protection Agency, Office of Water, 

Washington, DC. 

U.S. Environmental Protection Agency (USEPA). 1993b. Guidance Specifying Management 

Measures for Sources of Nonpoint Pollution in Coastal Waters. EPA-625-1-88-022. U.S. 

Environmental Protection Agency, Office of Water, Washington, DC. 

U.S. Environmental Protection Agency (USEPA). 1998a. Endocrine Disruptor Screening 

Program: Statement of Policy; Notice. U.S. Environmental Protection Agency. Federal 

Register, December 28, 1998, 63:71542. 

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Management Measure 6: New and Existing On-Site Wastewater Treatment Systems 

U.S. Environmental Protection Agency (USEPA). 1998b. Water Conservation Plan Guidelines—

Part 1: Information for States. http://www.epa.gov/owm/waterefficiency/wave0319/inform1.htm. Accessed January 15, 2002. 

U.S. Environmental Protection Agency (USEPA). 2001a. Constructed Wetlands Treatment of 

Municipal Wastewaters. EPA-625-R-99-010. 

http://www.epa.gov/ORD/NRMRL/pubs/625r99010/625r99010.pdf. Last updated April 

2001. Accessed January 15, 2002. 

U.S. Environmental Protection Agency (USEPA). 2001b. Estimate of National Gap for On-Site 

Wastewater Treatment Systems. Draft. U.S. Environmental Protection Agency, Office of 

Wetlands, Oceans, and Watersheds, Washington, DC. 

U.S. Environmental Protection Agency (USEPA). 2001c. Onsite Wastewater Treatment Systems 

Special Issues Fact Sheet 2: High-Organic-Strength Wastewaters (Including Garbage 

Grinders). U.S. Environmental Protection Agency, Washington, DC. 

U.S. Environmental Protection Agency (USEPA). 2002a. Onsite Wastewater Treatment System 

Manual. EPA/625/R-00/008. U.S. Environmental Protection Agency, Office of Water, 

Washington, DC, and Office of Research and Development, Cincinnati, OH. 

U.S. Environmental Protection Agency (USEPA). 2002b. Onsite Wastewater Treatment System 

Management Handbook. Draft. U.S. Environmental Protection Agency, Office of Water, 

Washington, DC, and Office of Research and Development, Cincinnati, OH. 

U.S. Environmental Protection Agency (USEPA). 2003. EPA Voluntary National Guidelines for 

Management of Onsite and Clustered(Decentralized) Wastewater Treatment Systems. 

EPA-832-B-03-001. U.S. Environmental Protection Agency, Office of Wastewater 

Management, Washington, DC.

U.S. Environmental Protection Agency. (USEPA). 1995. Process Design Manual: Land 

Application of Sewage Sludge and Domestic Septage. EPA-625-R-95-001. U.S. 

Environmental Protection Agency, Office of Research and Development, Cincinnati, OH. 

University of Massachusetts. 2000. Indian River Lagoon study calibrates nitrogen loading 

model. http://www.epa.gov/owow/estuaries/coastlines/jun00. Last updated September 6, 

2001. Accessed January 16, 2002. 

University of Missouri Extension Service. 1997. Residential Sewage Lagoon Systems: A 

Homeowner’s Guide to Installation and Maintenance. 

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15, 1997. Accessed July 17, 2000. 

University of Wisconsin. 1978. Management of Small Waste Flows. EPA-600/2-78-173. U.S. 

Environmental Protection Agency, Cincinnati, OH. 

Venhuizen, D. 1993. Colonia de Quemado Wastewater Facility Plan. http://www.venhuizenww.com/html/papers/pd_quemado.html. Accessed October 30, 2001. 

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Venhuizen, D. 1995. An Analysis of the Potential Impacts on Groundwater Quality of On-Site 

Wastewater Management Using Alternative Management Practices. 

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Venhuizen, D. 1997. A Minnesota Regulator’s Guide to the Venhuizen Standard Denitrifying 

Sand Filter Wastewater Reclamation System. 

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Venhuizen, D. 2000a. From wastewater to usable water. Water Tech Online. 

http://waternet.com/article.asp?indexid=5200205. Accessed July 17, 2000. 

Wallace, S.D. 2000. Design and performance of cold climate wetland treatment systems. In 

Proceedings of the National Onsite Wastewater Recycling Association 2000 Conference, 

Grand Rapids, MI, November 1–4, 2000. 

Washtenaw County, MI. 1999. Regulation for the Inspection of Residential Onsite Water and 

Sewage Disposal Systems at Time of Property Transfer. Washtenaw County, Michigan, 

Department of Environment and Infrastructure Services, Environmental Health Division, 

Ann Arbor, MI. 

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wastewater treatment using constructed wetlands. In Proceedings of the Eighth National 

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Agricultural Engineers, Orlando, FL, March 8–10, 1998. 

 

6-62 
Management Measure 7: Bridges and Highways 

MANAGEMENT MEASURE 7 

BRIDGES AND HIGHWAYS 

7.1 Management Measure 

Plan, design, operate, and maintain highways and bridges to: 

— Protect sensitive ecosystems, including wetlands and estuaries, by minimizing road- and 

bridge-related impacts and water crossings, and by establishing protective measures 

including setbacks during construction; 

— Reduce the runoff of pollutants through the use and proper maintenance of structural 

controls; 

— Reduce the generation of pollutants from maintenance operations by minimizing the use 

of pesticides, herbicides, fertilizers, and deicing salts and chemicals; and 

— Reduce the generation and runoff of pollutants during highway and bridge repair 

operations by decreasing the use of hazardous materials and incorporating practices to 

prevent spillage into sensitive areas. 

7.2 Management Measure Description and Selection 

7.2.1 Description 

Motor vehicles generate runoff pollutants through emission and deposition of automobile 

exhaust and through discharges of both fluids and solid particles while traveling and braking. In 

a study of traffic-generated particulates in Cincinnati (where the average daily traffic load is 

150,000 vehicles), Sansalone and Buchberger (1997) found that of the 13,500 mg of particulates 

per square meter of road surface generated per day, 44 to 49 percent originated from pavement 

wear, 28 to 31 percent from tire wear, and 15 percent from engine and brake pad wear. The study 

also found that 6 percent of particulates were deposited from settleable exhaust and 3 percent 

from atmospheric deposition. 

A study by Shepp (1996) examined generation of petroleum hydrocarbons in urban runoff from 

four land uses: all-day parking lots, streets, gas stations, and convenience stores. Shepp found 

that convenience stores had the highest hydrocarbon concentration (see Figure 7.1). Evaluation 

of the land uses and their respective catchment areas suggested that the degree of automotive 

exposure (a combination of duration of exposure to vehicles with engines running and volume of 

traffic) is the primary factor in the generation of petroleum hydrocarbons in runoff from 

automotive-intensive land uses. 

 7-1 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

1.9

0.7

4.2

6.6

0

1

2

3

4

5

6

7

All day parking Street Gas station Convenience

commercial

Evaluated Land Use Condition

Median Hydrocarbon Concentration (mg/l)

Figure 7.1: Median hydrocarbon concentrations by land use (Shepp, 1996). 

The National Water Quality Assessment Program (NAWQA) of the U.S. Geological Survey 

(USGS) recently conducted studies on water pollution related to sprawl-induced traffic. These 

studies show a consistently positive correlation between increases in vehicular traffic associated 

with urban sprawl and the buildup of polycyclic aromatic hydrocarbons (PAHs) in 10 lakes and 

reservoirs in six metropolitan areas across the country. PAH sources related to motor vehicle use 

include tire wear, roadway wear, exhaust and soot, and crankcase oil releases (Van Metre et al., 

2000). A study in Austin, Texas, demonstrated that elevated levels of PAHs found in Barton 

Springs sediments, although not toxic on their own, yielded 100 percent mortality in test 

invertebrates (amphipods, Hyalella azteca), when the organisms were exposed to UV radiation 

(Hayward et al., 2002). Mahler and Van Metre (2004) identified abrasion of coal tar emulsion 

sealants on parking lots as contributing significant amounts of PAHs to local water bodies and 

speculated that they could be the dominant source of PAHs in some urban watersheds. The U.S. 

Fish and Wildlife Service (USFWS) found that 50 to 68 percent of brown bullhead catfish 

collected from the Anacostia River in Washington, DC, had liver tumors and 13 to 23 percent 

had skin tumors (Reel, 2004). The USFWS attributed these tumors to DNA changes linked to 

PAHs from vehicle emissions and runoff. 

Roads tend to accumulate particulate matter from roadsides, salting and sanding, dirty cars, brake 

pad dust, aerial deposition, and surface deterioration. Sansalone and Tribouillard (1999) and 

Sansalone et al. (1998) measured the deposition and size distribution of particles deposited on 

highways. They found that accumulation of particulate matter was significantly greater along the 

7-2 
Management Measure 7: Bridges and Highways 

downslope of the highway than along the upslope and that particle size distributions (PSDs) 

along the downslope were consistently coarser across the entire size gradation than the upslope 

and pavement PSDs (Sansalone and Tribouillard, 1999). Solids in the 2 to 8 μm range generated 

the largest counts and were rapidly washed from the pavement in a “first flush” effect (Sansalone 

et al., 1998). Lateral pavement sheet flow rate and duration controlled the yield and size of 

transported solids; particle transport was mass-limited during extended, high-intensity events, but 

was flow-limited during intermittent, low-intensity events with high traffic (Sansalone et al., 

1998). 

These particles, when transported in runoff to receiving waters, contribute to high levels of total 

suspended solids and turbidity and act as carriers for pollutants that adhere to their surfaces. 

Because of this adsorption phenomenon, surface area can be an important determinant in 

pollutant loading from highways. A relationship exists between particle size and surface area. 

Sansalone et al. (1998) found that particles 425 μm to 850 μm in size contributed the greatest 

total surface area. Sansalone and Tribouillard (1999) found that total surface area decreased with 

decreasing particle size. Particle-specific surface area, however, increased with decreasing 

particle size (Sansalone and Tribouillard, 1999; Sansalone et al., 1998), but measured values 

deviated from the monotonic pattern expected for spherical particles (Sansalone et al., 1998). 

Because total surface area is predominantly associated with the coarser fraction, heavy metal 

mass (adhered to particle surfaces) is also strongly associated with this fraction (Cristina et al., 

2000). Cumulative analyses for lead, copper, cadmium, and zinc in snow residuals indicated that 

more than 50 percent of these heavy metals (by mass) was associated with particles greater than 

250 μm, and more than 80 percent was associated with particles greater than 50 μm (Sansalone 

and Glenn, unpublished). 

Heavy metals such as lead, iron, and aluminum are typically particulate-bound in urban runoff 

(Sansalone and Buchberger, 1997). Sansalone and Glenn (2000), however, found that lead was 

predominantly dissolved in highway runoff, a phenomenon they attributed to low urban rainfall 

pH and alkalinity and relatively short pavement residence times. Other metals predominantly 

found in the dissolved phase in highway runoff were zinc, cadmium, and copper (Sansalone and 

Buchberger, 1997; Sansalone and Glenn, 2000). 

The California Department of Transportation (Caltrans) conducted a study of highway runoff 

quality from 1999 to 2000 at 100 locations throughout the state. Caltrans found a positive 

correlation between the concentration of most pollutants and traffic volume. In addition, more 

than 30 percent of the total arsenic, cadmium, chromium, copper, nickel, silver, and zinc were 

found in the dissolved state (Kayhanian et al., 2001). 

The partitioning of heavy metals between the particulate-bound and dissolved fractions raises 

important questions for watershed managers regarding storm water treatment. It was previously 

thought that metals were associated with particulates and that removing sediment and reducing 

turbidity would address these pollutants. However, new research indicates that event mean 

concentrations of dissolved zinc, cadmium, and copper can exceed surface water quality 

discharge standards and can exhibit a “first flush” effect that cannot be mitigated by settling. In 

addition, the dissolved nature of these metals makes them highly mobile and bioavailable. 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Other pollutants found in highway runoff, along with their likely sources, are shown in Table 

7.1. Although runoff characteristics tend to be site-specific, a number of studies have been 

performed to compile typical concentrations of highway pollutants from a range of different 

locations from Northhampton, England, to Durham, North Carolina. Table 7.2 shows the range 

of values for highway contaminants presented by Newberry and Yonge (1996). These 

concentration levels vary significantly among the different locations. Suspended solids, for 

example, had concentration levels ranging from 45 mg/L to 798 mg/L; ranges for other 

parameters were even greater. For some pollutants, such as solids, heavy metals, and organics, 

concentration levels have been found to correlate with traffic volume. 

Table 7.1: Primary sources of highway runoff pollutants (Adapted from NCHRP, 1999). 

Pollutants Primary Source 

Particulates Pavement wear and vehicle maintenance 

Lead, cadmium, copper Tire wear, lubricating oil and grease, bearing wear 

Nitrogen, phosphorus Roadside fertilizer application 

Chromium, copper, nickel, cadmium Metal plating, moving engine parts, brake lining wear 

Chloride, sulfates Deicing salts 

PCBs, pesticides PCB catalyst in synthetic tires, spraying highway rights-of-way 

Cyanide Anti-cake compound used to keep deicing salt granular 

Petroleum, ethylene glycol Spills and leaks of motor lubricants, antifreeze, hydraulic fluids 

Table 7.2: Range of average values for runoff contaminant concentration for selected 

highway contaminants (Newberry and Yonge, 1996). 

Contaminant Concentration (mg/L) Load (kg/ha/yr) Load (kg/ha/event) 

Suspended solids 45–798 314–11,862 84–107.6 

Lead 0.073–1.78 0.08–21.2 0.008–0.22 

Phosphorus 0.073–1.78 0.6–8.23 — 

Biological oxygen demand 0.113–0.998 30.6–164 0.98 

Polycyclic aromatic hydrocarbons 12.7–37 0.005–0.018 — 

Runoff from the construction, operation, and maintenance of highways and bridges can adversely 

affect vegetation, surface waters, and wetlands with a variety of pollutants, including sediments, 

heavy metals, hydrocarbons, and toxic substances. Runoff issues associated with construction of 

highways and bridges are addressed in Management Measure 8—Construction Site Erosion, 

Sediment, and Chemical Control. Although the runoff constituents and concentration levels vary 

with highway type and location, the sources of highway runoff pollutants fall into three basic 

categories: vehicle traffic, snowmelt and ice-melt containing deicing chemicals, and chemicals 

used to manage roadside vegetation. 

The specific impacts of highway and bridge runoff on aquatic ecosystems are both site-specific 

and runoff event-specific. In general, highway pollutants can affect water quality through either 

acute toxicity or gradual accumulation. Potential adverse environmental effects associated with 

specific constituents include the following: 

— Suspended solids increase turbidity, transport other pollutants adhered to particle 

surfaces, and reduce runoff storage capacity in ponds and lakes. 

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Management Measure 7: Bridges and Highways 

— Heavy metals are toxic to many aquatic organisms and can bioaccumulate in fish tissues, 

thus posing potential health risks to humans. 

— Nutrients degrade water quality by stimulating the growth of algae and aquatic weeds. 

Rapid increases in these populations can then deplete oxygen levels to the extent that fish 

and other aerobic organisms die off. 

— Biochemical oxygen demand (BOD) reduces dissolved oxygen levels as a result of the 

biological processes that break down organic constituents in runoff. 

— PAHs include compounds such as benzo(a)pyrene that are found in petroleum products 

and are carcinogenic. These compounds can pose risks to human health if drinking water 

or fish become contaminated with them. PAHs in streams and lakes usually do not pose a 

health risk for people because they tend to adhere to sediment particles rather than 

dissolve in water. As a result, the risk of drinking water degradation is low (Van Metre et 

al., 2000). Aquatic invertebrates were impacted in the previously identified study from 

Austin, Texas (Hayward et al., 2002). 

Paved roadways often generate higher loads of metals and toxicants than other nonpoint source 

pollutants1

. Nutrient loadings from highways tend to be of concern when they are located 

upstream of a reservoir or estuary. 

Winter maintenance activities to prevent ice and snow buildup on highways can also be 

significant contributors to loadings of particulates, salts, and various other chemicals. Salts in 

particular can harm both vegetation and aquatic ecosystems. Other highway maintenance 

activities, including roadside vegetation management, can also contribute herbicides, pesticides, 

and nutrients to runoff pollutant loads. 

In several studies, Sansalone and Glenn (2002a, 2002b, and unpublished) examined the 

characteristics of snowbanks and snowmelt. Table 7.3 summarizes their findings for several 

pollutants and physical characteristics. From their research, they concluded the following: 

— Traffic and winter maintenance practices generate significant levels of inorganic and 

organic constituents, many of which become predominantly particulate-bound in the 

snowbank with increasing residence time. 

— The accretion of traffic-generated constituents in urban highway snow is relatively rapid 

within the first 12 hours of the snowbank’s exposure to traffic. 

A research team at Oregon State University, under the National Cooperative Highway Research 

Program (NCHRP, 2000) identified potentially mobile constituents from highway construction 

and repair materials and measured their potential impact on surface and ground waters. The 

 

1

 Several recent studies cited by the Federal Highway Administration (FHWA) indicate that few significant 

environmental impacts have been associated with roads with an average daily traffic volume of less than 30,000 

vehicles (USDOT, 1996). 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

materials tested were conventional, recycled, and waste materials; and excluded constituents 

originating from construction processes, vehicle operation, maintenance operations, and 

atmospheric deposition. The research team established laboratory methods to realistically 

simulate the leaching of constituents from construction and repair materials in typical highway 

environments. They also established methods to evaluate the removal, reduction, and retardation 

of leached constituents by environmental processes in the highway right-of-way. The team 

produced extensive data sets of laboratory test results for highway construction and repair 

materials, and they expressed the results as aquatic toxicity and chemical concentrations. They 

then developed a software program called IMPACT, which estimates the fate and transport of 

leachates surrounding the highway right-of-way. IMPACT contains an extensive, readily 

accessible database of laboratory test results for materials ranging from common construction 

and repair products to waste and recycled materials proposed for use in highway construction. 

Table 7.3: Results of three studies that analyzed chemical and physical parameters of 

snowmelt (Sansalone and Glenn, 2002a, 2002b, and unpublished). 

Parameter Result 

Bulk density Bulk densities increased as TSS accumulation continued and the snow matrix began 

to melt or evaporate. 

Particle size distribution 

and bulk density 

For all sites, particle sizes ranged from 10,000 μm to less than 25 μm, with a mean 

bulk density of 1,225 μm. 

Specific gravity Specific gravity of residual solids ranged from 2.5 to 3.2 g/cm3 across the gradations; 

the lower specific gravity was associated with particles less than 100 μm. 

Chloride and conductivity Conductivity and chloride concentrations increased rapidly at first because of initial 

deicing salt applications at each site. Strong correlations indicated that conductivity 

trends were mainly a function of chloride trends. 

Hardness Hardness increased rapidly to nearly 100 mg/L during initial snow accumulation and 

remained relatively constant (100–300 mg/L) for most of the study. This increase is 

likely a result of liquid CaCl2 mixed with rock salt and CaCO3 as part of the TSS 

captured by the snow matrix. 

COD Temporal trends toward increasing total chemical oxygen demand (COD) exerted by 

roadway snow are similar to trends in TSS, with COD values of 100,000 mg/L. 

TDS and TSS Although accretion of total dissolved solids (TDS) was initially rapid with a decrease 

late in the event, total suspended solids (TSS) accretion demonstrated a more gradual 

increasing trend for the duration of roadway snow, approaching 100,000 mg/L. 

Cyanide Applications of 216,000 kg of rock salt containing cyanide as an anti-caking agent 

resulted in a discharge of approximately 6 kg of cyanide along the interstate. 

Metals Concentrations for lead, copper, cadmium, zinc, and cyanide were orders of 

magnitude higher than those of the control site and exceeded storm water runoff 

concentrations by 1 to 2 orders of magnitude. 

Note: TSS = total suspended solids, TDS = total dissolved solids, COD = chemical oxygen demand, CaCl2 = calcium chloride, 

CaCO3 = calcium carbonate. 

7.2.2 Management Measure Selection 

This management measure was selected to provide general guidance on practices that can be 

integrated into highway and bridge maintenance and repair operations. The management measure 

also includes guidance for siting and constructing highways and bridges. The management 

measures for watershed protection; site development; new development runoff treatment; and 

construction site erosion, sediment, and chemical control (Management Measures 3, 4, 5, and 8) 

are also applicable to the planning and constructing of highways and bridges. 

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Management Measure 7: Bridges and Highways 

7.3 Management Practices 

The use of structural and nonstructural runoff control practices during the planning, design, 

operation, and maintenance of highways and bridges can significantly mitigate the adverse 

effects of runoff. Specifically, by using environmentally sensitive highway and bridge designs 

and implementing proper operation and maintenance practices, highway authorities can reduce 

both the volume and concentration of contaminants generated by motor vehicle traffic and 

maintenance and repair operations. In addition, controls can be used to store and treat 

contaminants so that pollutant loadings can be further reduced or prevented from entering 

sensitive ecosystems. 

7.3.1 Site Planning and Design Practices 

A wide range of environmental planning and design management practices, especially those 

presented in Management Measures 3 and 4, can be used to reduce the environmental impacts of 

highways and bridges and can be initiated long before a road is completed. In general, highways 

and bridges should be planned so that mileage through sensitive environments, such as wetlands 

and estuaries, is minimized. River crossings should be avoided if possible, and sufficient 

setbacks should be established during construction to minimize disturbance of the surrounding 

environment. During the siting process, consideration should also be given to maintaining 

sufficient setbacks for the protection of drinking water sources. Efforts should be taken to avoid 

channelization and floodplain alteration to allow natural processes to continue after roads are in 

place. 

Highway development is most disruptive adjacent to water bodies, riparian areas, and wetland 

areas because it increases sediment loss, alters surface drainage patterns, changes the subsurface 

water table, and results in loss of wetland and riparian habitat. Highway structures should not 

restrict tidal flows into salt marshes and other coastal wetland areas because such restrictions 

might facilitate the intrusion of freshwater plants and reduce the growth of salt-tolerant species. 

To safeguard these fragile areas, highways should be sited with sufficient setback distances 

between the highway right-of-way and any wetlands or riparian areas. 

Bridge construction can also adversely affect water circulation and quality in wetland areas, 

necessitating special techniques to accommodate construction. By locating highways and bridges 

away from sensitive areas and establishing buffer zones where possible, environmental 

degradation from erosion and runoff can be mitigated during construction, operation, and 

maintenance of roadways. 

As discussed previously, roads and highways have been shown to accumulate pollutants that are 

carried in runoff. Decreasing impervious cover by reducing the area of pavement or number of 

road miles could lower this pollution potential. However, each individual community should 

weigh the benefits of alternative road designs against the use of low-impact development 

techniques or treatment controls (see Management Measures 4 and 5, respectively). Where road 

surfaces are constructed, disconnecting and infiltrating runoff using structural runoff controls can 

mitigate impacts of roads and provide sufficient water quality protection. 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

7.3.2 Soil Bioengineering and Other Runoff Controls for Highways 

Soil bioengineering techniques can be used to augment or replace structural slope stabilization 

practices such as retaining walls. They are appropriate for relatively moderate slopes where 

vegetation can be established easily. Soil bioengineering techniques can create wildlife habitats 

and promote infiltration of rainfall and runoff in addition to stabilizing slopes. Installation of 

bioengineering practices can be labor-intensive, and periodic inspection and maintenance, 

especially after large storms, is necessary to repair slumps and replace dead vegetation. Soil 

engineers or scientists should confirm that the stability and structural integrity of the site are 

appropriate for soil bioengineering practices. Several kinds of soil bioengineering practices are 

described by the U.S. Department of Agriculture (USDA, 1992): 

7.3.2.1 Live stakes 

The use of live stakes involves inserting and tamping live, rootable vegetative cuttings into the 

ground to create a living root mat that stabilizes the soil by reinforcing and binding soil particles 

together and extracting excess soil moisture. Live stakes are appropriate for repairing small earth 

slips and slumps caused by excessively wet soil and should be used only at sites with relatively 

uncomplicated conditions. They are especially useful when construction time is limited and an 

inexpensive method is desired. They can be used to secure erosion control measures and can be 

used in combination with other bioengineering techniques. Finally, they facilitate plant 

colonization by providing a favorable microclimate for plant growth. Native species that are 

appropriate for the soil conditions onsite should be used wherever possible. 

7.3.2.2 Fascines 

Fascines are long bundles of branch cuttings bound together into sausage-like structures. They 

are installed in contoured or angled trenches and are secured to the slope with both live and dead 

stakes. They reduce surface erosion and rilling, protect slopes from shallow slides, and reduce 

long slopes into a series of shorter slopes that trap and hold soil. They also enhance vegetative 

growth by creating a microclimate conducive to plant growth. 

7.3.2.3 Brushlayers 

Brushlayering is much like the fascine technique except branches are placed perpendicular to the 

slope contour. This method is more effective than fascines with respect to earth reinforcement 

and mass stability. Brushlayers break up the slope length, preventing surface erosion, and 

reinforce the soil with branch stems and roots, providing resistance to sliding or shear 

displacement. Brushlayers also trap debris, aid infiltration on dry slopes, dry excessively wet 

sites, and mitigate slope seepage by acting as horizontal drains. Brushlayers facilitate vegetation 

establishment by providing a stable slope and a favorable microclimate for growth. 

7.3.2.4 Branchpacking 

Branchpacking involves reinforcing a slope with alternating layers of live branch cuttings and 

compacted backfill. This technique is useful to repair small, localized slumps and holes in 

earthen embankments other than dams. Branchpacking produces a filter barrier that reduces 

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Management Measure 7: Bridges and Highways 

erosion and scouring and provides immediate soil reinforcement. Branchpacking is not effective 

in slump areas more than 4 feet deep or 5 feet wide. 

7.3.2.5 Live gully repair 

Live gully repair is a technique that is similar to branchpacking but is used to repair rills and 

gullies. Live gully repairs offer immediate reinforcement and reduce the velocity of concentrated 

flows. They also provide a filter barrier that reduces further rill and gully erosion. This technique 

is appropriate only to repair rills or gullies less than 2 feet wide, 1 foot deep, and 15 feet long. 

7.3.2.6 Live cribwalls 

A live cribwall is a hollow, boxlike structure of interlocking untreated logs or timber members 

installed with backfill material and layers of live branch cuttings. The live cuttings eventually 

take over the structural functions of the wall once the roots have become established. Live 

cribwalls are appropriate for stabilizing the toe of a slope and reducing its steepness. They should 

not be used in areas that are subject to large lateral stresses. Cribwalls provide both immediate 

and long-term stabilization and are useful where space is limited. They should be tilted if the 

system is built on a smoothly sloped surface, or they can be constructed in a stair-step fashion. 

7.3.2.7 Vegetated rock gabions 

Vegetated rock gabions consist of wire mesh or chain-link baskets layered with live branch 

cuttings that take root inside the gabions and bind the structure to the slope. These structures are 

appropriate for stabilizing the toe of a slope and reducing its steepness, especially in areas where 

space is limited. They should not be used in areas that are subject to large lateral stresses and 

should not be more than 5 feet tall. 

7.3.2.8 Vegetated rock walls 

Vegetated rock walls consist of a combination of rocks and live branch cuttings used to stabilize 

the toe of steep slopes. These structures are appropriate for stabilizing areas where space is 

limited and natural rock is available. The wall should not exceed 5 feet in height. 

7.3.2.9 Joint planting 

Joint planting stabilizes slope faces by planting live cuttings in spaces between the stones of 

riprap. The plantings improve drainage, bind rock materials to the slope, and help prevent 

washout of fine materials. Joint planting can be used where riprap has already been installed, or 

it can be part of a new riprap installation. 

7.3.2.10 Other runoff and sediment controls for highways 

Other runoff controls, such as grassed swales and filter strips, wet ponds, extended detention dry 

ponds, and storm water wetlands, can be used to control highway runoff. These measures are 

described in detail in Management Measure 5. Additionally, sediment traps and basins and inlet 

protection (described in Management Measure 8) can be used to collect runoff from highways, 

especially during construction and repair operations when pollutant loadings are great. 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

In Delaware County, New York, the Department of Public Works (DPW) is extending its highway 

runoff management program to include town roads. This involves inventorying and assessing town 

roads, identifying priority storm water management needs, training highway superintendents, and 

evaluating and monitoring management practices. The DPW plans to dedicate a storm water/highway 

engineer to assist towns in prioritizing their highway storm water projects. Funding will be provided 

through the Catskill Watershed Corporation’s Stormwater Retrofit Program and matched with capital 

planning funds in town highway budgets. The intent of the program is to maximize efficiency by 

targeting the areas critically in need of redesign, repair, and rebuilding (Delaware County Departments 

of Planning and Public Works, 2003). For more information, contact the Delaware County Department 

of Watershed Affairs, (607) 746-8914. 

Highway Management Plans for Storm Water Control

7.3.3 Structural Runoff Controls for Bridges 

Highway runoff controls have been extensively documented and implemented. A mitigation 

strategy specific to bridges is crucial, however, because of the unique limitations associated with 

bridge building and repair. These limitations include (Transportation Research Board, 2002a): 

- A lack of lateral right-of-way on which to build mitigation measures, causing runoff to be 

drained back onto land; 

- Topographic and slope constraints at some bridges that prohibit gravity drainage back to 

land; 

- The need to factor additional weight of storm water piping into the design of a new or 

retrofitted bridge; and 

- The need to address maintenance constraints and safety concerns. 

The Transportation Research Board (TRB) (2002b) developed a report that addresses these and 

other issues specific to bridge runoff. The TRB described a process for assessing sites for the 

potential for bridge deck runoff to cause water quality problems and for developing mitigation 

procedures. The process is particularly applicable in the case of large bridge construction or 

reconstruction projects over sensitive or highly valued receiving waters. It is also applicable in 

cases where regulations and policies are ambiguous or require reconsideration. This report, 

Assessing the Impacts of Bridge Deck Runoff Contaminants in Receiving Waters, is available 

from the TRB at http://www.trb.org/. 

7.3.3.1 Scupper drains with runoff conveyance systems 

Bridges have traditionally been designed to direct runoff away from the roadway as efficiently as 

possible without regard to impacts on the environment below the deck. While there is a 

significant body of research on the environmental impacts of highway runoff, there are few 

studies that directly address the chemical characteristics of runoff from bridge decks, and even 

fewer that also address the effects of that runoff on biota or other receiving water uses. Several 

studies have shown that direct scupper drainage into some types of water bodies, such as small 

lakes, can result in localized increases of metal concentrations in sediments and in aquatic biota. 

(TRB, 2002a). 

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Management Measure 7: Bridges and Highways 

More recently, bridge designs have been enhanced to address the potential effects of runoff 

pollutant loadings, especially on water bodies. The most prevalent mitigation practice is to direct 

the drainage from the bridge to an on-shore treatment system. For example, the runoff can be 

conveyed from scupper drains through a pipe onto the shore, from which it is sent to a retention 

pond or other runoff treatment practice. A scupper drain is an opening in the floor of a bridge 

that provides a means for rain or other water accumulated on the roadway surface to drain into 

the space beneath the structure (ODOT, 2001). Rather than draining directly to the water below, 

the runoff can be routed to the shore for treatment. The FHWA and EPA have developed 

recommendations on the design and use of scupper drains to address bridge deck runoff. Among 

the practices they recommend are: 

— The spacing between scuppers should be maximized in accordance with established 

maximum hydrologic and hydraulic design. As scupper spacing increases, the volume of 

water that passes through each scupper increases, thus creating velocities high enough to 

flush outlets clogged by deposits from low-volume rainfalls. 

— Careful detailing is critical when connecting scuppers to drain pipes. Because of poorly 

designed routing, drain pipes often create more problems than they prevent. For example, 

piping that is routed with too many elbows can easily clog, resulting in a buildup of 

contaminated runoff. 

— Gravity flow collection systems should be used wherever possible. 

Collection systems for scupper drains may be used to minimize the impacts of bridge runoff, 

although they may be expensive. Depending on the length of the bridge and traffic volume, as 

well as river size and climate, bridge runoff might constitute only a small fraction of the overall 

pollutant load to a receiving water body. Furthermore, the topography and approach slope at 

some bridge locations might preclude design or retrofit for gravity drainage back to land, 

therefore requiring the use of a pump to discharge the runoff into a suitable water quality 

treatment practice (TRB, 2002a). The addition of pumps could significantly increase the cost of 

the collection system and operation and maintenance requirements. In some cases, controlling 

runoff from other pollutant sources may be more cost-effective when a watershed approach is 

used. 

7.3.3.2 Other runoff treatment practices 

Runoff treatment practices like ponds, wetlands, infiltration basins and trenches, media filters, 

bioretention areas, vegetated swales, filter strips, and hydrodynamic devices (see Management 

Measure 5) can be installed on the shore to treat runoff collected and routed by scupper drains 

and pipes. If a bridge does not have scupper drains, runoff can be routed to the shore via gutters. 

Depending on site conditions, such as the space available for the practice, the suitability of the 

soils for filtration or infiltration, and the quantity and quality of the bridge runoff, some practices 

may be more cost-effective than others. 

7.3.4 Bridge Operation and Maintenance Controls 

Bridge repairs are those activities necessary to maintain the structural integrity and designated 

use of the bridge. Bridge repairs encompass a wide array of activities, ranging from minor 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

operation practices, such as line painting, to major structural repairs. Bridge scraping and 

painting, which are required to prevent corrosion, can be significant sources of pollutant loads if 

proper management practices are not used. 

Of the most common bridge maintenance activities, bridge painting has the greatest potential for 

environmental impact. A 1996 study found that up to 80 percent of steel bridges repainted each 

year had been painted with lead paint, and this material along with cleaners and abrasives, can 

directly enter the surrounding environment (Young et al., 1996). Paint overspray and solvents 

can be toxic to aquatic life (Dalton et al., 1985), and metal bridge cleaning has been found to 

pose a serious water quality problem (TRB, 2002b). The cost of implementing measures to 

mitigate the impacts of bridge painting are estimated to be an additional 10 to 20 percent for 

containment and 10 to 15 percent for waste disposal (Young et al, 1996). 

Although most construction activities take place away from water bodies, bridge operation and 

maintenance activities occur within close proximity to a water body. Therefore, management 

practices to minimize potential adverse effects on the surrounding environment are 

recommended. It should be noted that, in some cases, federal regulations, including Section 404 

of the Clean Water Act and Section 9 of the Rivers and Harbors Act (33 USC 401) might apply 

to these construction activities. Section 404 regulates the discharge of dredged or fill material to 

the aquatic environment or the nation's waters. Section 9 of the Rivers and Harbors Act prohibits 

the construction of any bridge, dam, dike, or causeway over or in navigable waterways without 

Congressional approval. 

7.3.4.1 Enclosures 

The following types of enclosures can be used to collect pollutants during bridge maintenance: 

(1) Free-hanging enclosures. Free-hanging enclosures include tarps, drapes, plastic sheeting, 

screens, and rigid panels of which only two corners (or one side) are supported. Free-hanging 

tarps generally provide relatively low containment efficiency (estimated at no more than 50 

percent). Considerations for material selection include visibility inside the enclosure, material 

strength, and air permeability. Free-hanging enclosures are not practical for large, high 

bridges where high winds can rip the materials or create a “sail effect.” 

(2) Total structural enclosures. Total structural enclosures are drapes, tarps, screens, plastic 

sheeting, or rigid panels attached to a rigid steel or wood framework, scaffolding, or existing 

walls. Design considerations include interior air quality, visibility, structural adequacy of the 

enclosure, portability, and reusability. Enclosures can be used to encapsulate only part of a 

large structure at a time. Therefore, portability and reusability should be considered. 

(3) Negative pressure systems. Negative pressure containment systems are used to prevent dust 

from escaping from an enclosure when pressurized air blasting is used for paint removal. 

Such systems draw outside air into the enclosure to the surface being treated; the air then 

exits through a filter system. The resulting continuous air exchange eliminates leaks of paint 

dust and abrasives to the outside, improves worker visibility, and reduces health hazards and 

dust accumulation on structural surfaces and equipment. These systems can be cumbersome 

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Management Measure 7: Bridges and Highways 

and expensive, however, and it is sometimes difficult to maintain a constant negative 

pressure in the enclosure. 

7.3.4.2 Containment and collection 

Fully enclosed containment structures have been found to recover 80 to 95 percent of abrasives, 

paint particles, and dust (Appleman, 1992). The following practices can be used to contain 

and/or collect pollutants during bridge maintenance activities: 

(1) Cofferdams. Cofferdams are temporary structures used to displace water and provide dry 

access to submerged support structures for bridges. Cofferdams can be used during bridge 

construction and maintenance operations involving painting or repairing of steel structures 

that are in contact with the water body. 

(2) Barges. Barges situated below the bridge with tarps or shields attached from the barge to the 

bridge or work platform can be used for debris capture, although winds often make this 

practice infeasible. 

(3) Containment booms. Containment booms can be placed in underlying waters to capture 

floating debris (e.g., paint chips, fines). Lead particles and abrasives usually sink, but use of 

booms keeps these materials from spreading downstream while they are suspended in the 

water column. 

(4) Vacuum sanders. Vacuum sanders can be used to remove paint from bridges and collect dust 

and chips. Sanders have been shown to immediately capture 98 percent of the dust generated, 

which reduces cleanup of containment areas and offers increased safety to maintenance 

workers (USEPA, 2001). 

7.3.5 Nonstructural Runoff Control Practices 

The structural management practices for highways and bridge decks described previously are 

designed to reduce pollutant loadings to the environment by holding and treating the highway 

runoff generated by precipitation. Nonstructural management practices are designed to achieve 

source control and can be used to augment on-site structural or other runoff management 

facilities. Most of the nonstructural practices for managing highway runoff pollution are 

applicable to virtually all highway situations, even if a specific runoff problem has not been 

identified. 

The following management practices for highway runoff are intended to reduce the volume of 

particulates available for transport by runoff or to filter and settle out suspended solids. Although 

the practices described do not represent the complete universe of highway management 

practices, they are among those commonly implemented across the United States. 

7.3.5.1 Implement street sweeping 

Curb systems act as traps for particulates and other pollutants. The advantage of wellmaintained, traditional curbs is that they trap pollutants on the paved surface, and when 

combined with regular vacuum street sweeping, they can be effective at removing pollutants 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

prior to mobilization in runoff. However, if they are not properly maintained, pollutants build up 

and are washed out by storm water. 

Street sweeping is a common practice in many communities. Street sweeping programs can be 

optimized to significantly reduce trash and other pollutants on urban streets. Study results 

suggest that reductions of up to 80 percent in annual TSS and associated pollutants could be 

achieved by using bimonthly to weekly sweepings. Sweeping frequency would vary with 

patterns of precipitation, sediment accumulation, and resuspension. The effectiveness of any 

street sweeping operation will vary with land use, precipitation, and the accumulation dynamics 

of contaminated sediments (Sutherland and Jelen, 1997). Table 7.4 shows concentrations of 

constituents often found in street dirt. 

Table 7.4: Street dirt chemical quality (Bannerman et al., 1983; Pitt, 1979; Pitt, 1985; Pitt, 

2001). 

Constituent 

Mass of Constituent in Street Dirt 

(mg constituent / kg total solids) 

Phosphorus 400–1,500 

Total Kjeldahl Nitrogen 290–4,300 

Chemical Oxygen Demand 65,000–340,000 

Copper 110–420 

Lead 530–7,500 

Zinc 260–1,200 

Cadmium <3–5 

Chromium 31–180 

 

Sweeping technology can have a profound effect on sweeping results. Previously, sweepers were 

unable to pickup very fine sediments that can be highly contaminated. One study found that the 

effectiveness of conventional street sweeping equipment ranged from a 35 percent removal of 

large particles to an increase in the loading of small particles by 10 percent. The equipment 

performed more efficiently on a smooth asphalt street, showing a 12 percent reduction in small 

particles (Pitt, 2001). Today, new street sweeping technology has proven to be an effective 

management practice for reducing pollutant loads to waterways. High-efficiency pavement 

sweepers are thought to be very effective at picking up a large portion of the very fine particulate 

material that accumulates on street surfaces. A high-efficiency sweeper uses strong vacuums and 

the mechanical action of brooms, combined with an air filtration system that returns only clean 

air to the atmosphere. Minton et al. (1998) found that simulated results for high-efficiency 

sweepers in residential areas reduced annual TSS wash-off by 51 to 87 percent. Other sweepers 

reduced annual TSS in these same areas by up to 71 percent. When sweeping in major arterials 

with high pollutant loads, simulated results indicated that annual TSS wash-off was reduced by 

49 to 85 percent. Other tested sweepers reduced annual TSS wash-off in major arterials by up to 

24 percent (Minton et al., 1998). When a high-efficiency sweeper was tested in a tandem sweep 

behind a mechanical broom sweeper, it was able to pick up 141 percent more material than the 

mechanical broom sweeper (Schwarze Industries, 2004). When the high-efficiency sweeper 

swept directly after a regenerative air sweeper, it was able to pick up 44 percent additional 

material. 

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Management Measure 7: Bridges and Highways 

High-efficiency sweepers were also compared to wet detention vaults (see Section 5.3.1.1; 

Sutherland et al., 1998). Simulated results indicate that high-efficiency sweepers removed 40 to 

75 percent of annual TSS, while wet detention vaults removed 75 to 91 percent. All removal 

efficiency ranges depended on sweeping frequency. These projected water quality benefits of 

high-efficiency street sweeping are based on modeling. 

7.3.5.2 Consider alternatives to curbs 

As a design alternative, eliminating curbs from roads and highways allows runoff to be filtered 

through vegetated shoulders or medians and infiltrate to the ground water. Where curbs are 

necessary for traffic control or other reasons, curb breaks can be incorporated to disconnect the 

impervious surface and direct runoff to pervious areas. This may not be feasible for streets with 

high traffic volume and/or on-street parking demand. The structural integrity of the pavement 

can be maintained by “hardening” the interface between the swale and the pavement with grass 

pavers, geo-synthetics, or a low-rising concrete strip along the pavement edge. Maintenance 

requirements for grass channels are generally comparable to those of curb and gutter systems and 

involve turf mowing, debris removal, and periodic inspections. 

7.3.5.3 Install catch basin inserts 

Catch basin inserts can be used to treat pollutants in runoff from curbs and road surfaces before 

entering the storm drain system. These devices are discussed in detail in Management Measure 5 

(section 5.3.5.4). 

7.3.5.4 Control litter and debris on roadsides 

Roadside litter control practices that have traditionally been implemented to address health and 

aesthetic concerns can also improve runoff quality by limiting trash in runoff conveyance and 

treatment systems and receiving water bodies. An effective litter and debris control program 

should include the following source controls: 

— Conducting regular trash and debris removal and disposal; 

— Educating the public with signs along roads and at rest areas; 

— Enforcing littering and illegal dumping laws; 

— Sealing cracks and applying pothole surface treatments that minimize the loosening of 

aggregate and road base debris by tires; and 

— Sponsoring Adopt-A-Highway or Adopt-A-Road programs. Many state highway 

administrations or departments of transportation sponsor Adopt-A-Highway programs 

that allow businesses and community groups to conduct litter removal and beautification 

activities on state-owned roads. The city and county equivalent is called Adopt-A-Road. 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

7.3.5.5 Manage pesticide and herbicide use 

Over-application of pesticides and herbicides may cause excess chemicals to leach to ground 

waters or flow into surface waters. Herbicides and pesticides have the same toxic effect on 

aquatic plants and organisms as they do on the terrestrial plants and organisms to which they 

were applied. Practices such as applying according to label instructions, applying at the proper 

time, applying only the types and amounts necessary, and considering the environmental 

conditions and hazards at the site are important ways to prevent pesticides and herbicides from 

entering water bodies. Pesticides, herbicides, and integrated pest management are discussed at 

length in Management Measure 9 (section 9.3.2). 

7.3.5.6 Reduce fertilizer use 

Improper application of fertilizers along roadsides can result in excess nutrients being 

transported to surface waters or leaching to ground water. Methods to reduce fertilizer use are 

presented in detail in Management Measure 9 (section 9.3.2). 

7.3.5.7 Reduce direct discharges 

Direct discharges of highway runoff to receiving waters should be avoided wherever possible. 

This involves the use of collection/conveyance through closed conduits. Highway runoff should 

be routed through one or a combination of runoff treatment practices, as described in 

Management Measure 5, before it is discharged to receiving waters. 

7.3.5.8 Practice dewatering 

Dewatering is a temporary method used to filter sediment-laden water from excavated areas on 

construction sites prior to discharge to a storm drain or surface waters. Dewatering pumps are 

applicable wherever sediment-laden water must be removed from a construction site. Dewatering 

practices should be considered a last-resort control measure. Adequate erosion and sediment 

control measures must be considered first. 

7.3.5.9 Practice spill prevention and control 

Prevention and control of spills eliminates or minimizes the discharge of pollutants to water 

bodies. Water bodies adjacent to construction sites are at highest risk of contamination from an 

uncontained spill. Several steps can be taken to reduce the risks: handle hazardous and 

nonhazardous materials, such as concrete, solvents, asphalt, sealants, and fuels, as infrequently as 

possible and observe all federal, state, and local regulations when using, handling, or disposing 

of these materials. Spill control devices such as absorbent snakes and mats should be placed 

around chemical storage areas, and they can be used in an emergency to contain a spill. 

7.3.5.10 Properly handle and dispose of concrete and cement 

Concrete and cement-related mortars can be toxic to aquatic life. Proper handling and disposal 

should minimize or eliminate discharges into watercourses. Fresh concrete and cement mortar 

should not be mixed on-site, and both dry and wet materials should be stored away from water 

bodies and storm drains. These materials should be covered and contained to prevent contact 

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Management Measure 7: Bridges and Highways 

with rainfall or runoff. Washout should not be discharged into streets, storm drains, drainage 

ditches, or watercourses. A washout area should be designated, and wash water should be treated 

on-site or discharged to the sanitary sewer. 

7.3.5.11 Manage contaminated soil and water 

Soil, ponded runoff, and ground water can become contaminated if exposed to hazardous 

materials and should be properly managed to prevent health hazards and minimize or eliminate 

discharge of pollutants to storm drains and watercourses. Excavation, transport, and disposal of 

contaminated soil and water, as well as hazardous waste, must be in accordance with the rules 

and regulations of EPA, the U.S. Department of Transportation, the Department of Toxic 

Substances Control, and state and local regulatory agencies. 

7.3.5.12 Practice environmentally friendly winter road maintenance 

Some of the most damaging runoff can be generated from the melting of snow or ice that has 

been treated with salts or other chemicals. For example, the buildup of salts along roadsides over 

the course of a winter can damage and reduce the effectiveness of structural controls such as 

vegetative filter strips and grass-lined channels. Salts in surface or ground waters can adversely 

affect water quality and damage wetlands. The corrosive effects of salts also damage road 

infrastructure, especially bridge decks. According to TRB (1991), road salt has caused more 

premature bridge deck deterioration than any other factor. 

Deicing chemicals deposited on road surfaces can contaminate runoff, as can chemicals that are 

stored in a manner that puts them in contact with precipitation or runoff. Plowed snow piled in 

parking lots and along roadsides often contains pollutants such as chlorides, sand, and grit, as 

well as hydrocarbons and heavy metals. These piles should not be deposited into water bodies or 

stored near water bodies. Treated snow should never be stored on a frozen pond surface because 

it can cause density stratification, which can prevent reoxygenation in addition to chloride 

problems. 

Three general types of management practices can be employed to reduce the impact of salt 

damage on the environment. The first is to implement anti-icing operations that help reduce the 

amount of chemicals required to maintain safe road conditions; the second is to use alternative 

deicing materials, which are less corrosive and are presumably less damaging to the 

environment. The third is to properly store salts or other deicing chemicals to prevent runoff 

contamination. 

(1) Anti-icing operations. Anti-icing operations are performed before a storm starts. The purpose 

of these operations is to prevent snow or ice from accumulating on road surfaces. One of the 

main advantages of successful anti-icing strategies is reducing the amount of chemicals and 

abrasives used to keep roads clear. Since 1994, 15 states have participated in the FHWA's 

project to test and evaluate the effectiveness of anti-icing operations. Anti-icing operations 

typically use the same chemicals used for deicing, but in different forms. For example, test 

results found that pre-wetting deicing salt and using brine solutions are effective approaches 

and result in fewer handling problems. 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

The ultimate success of anti-icing operations depends on the timing of application. Central to 

this approach is the use of Roadway Weather Information Systems (RWIS), which report 

road conditions through pavement sensors that monitor pavement temperatures and the 

amount of anti-icing materials present on the pavement. When this information is combined 

with meteorological data and fed into a central database, various modeling techniques can be 

applied to accurately predict the start of ice formation on pavements and the appropriate 

times to start anti-icing operations. The cost of implementing and maintaining an RWIS must 

be compared to the cost of labor and materials for deicing and snow removal. For example, 

the West Virginia Parkway Authority installed four RWIS units along a 95-mile stretch of 

highway and calculated that the agency was able to save sufficient outlays for materials and 

labor to pay for the system within a year. In a state with fewer snowstorms, however, the 

economics of installing an RWIS may be less advantageous. 

Another technology option is the installation of infrared sensors on the bottoms of 

snowplows. These sensors measure the actual temperature of the roadway as the truck passes 

over it, allowing a more accurate calculation of the amount of salt needed. As part of its 

“smart salting” program, the Vermont Department of Transportation installed trial sensors on 

the bottoms of four snowplows. The agency estimates that it was using 20 to 30 percent more 

salt than needed because of inaccurate temperature readings. The program has currently been 

expanded statewide, where the average reduction in salt usage is 28 percent, resulting in an 

approximate savings of $2.2 million (Lehner et al., 1999). 

(2) Alternative deicers. Over the years, the FHWA and numerous states have experimented with 

alternative deicing chemicals, including liquid calcium magnesium acetate (CMA), liquid 

calcium chloride, liquid magnesium chloride, and liquid potassium acetate. Research has 

found that these chemicals have both advantages and disadvantages compared to salt (see 

Table 7.5). Calcium chloride works better at lower temperatures but is also corrosive. CMA 

appears to be much less harmful to the environment. Its disadvantage is that it is significantly 

more expensive than salt; the NRC estimated that CMA can cost 20 times more than salt and 

would increase the total cost of chemical application five-fold (Chollar, 1996). CMA is also 

less successful than other salts at lower temperatures and is slower to act than salt. 

Table 7.5: Advantages and disadvantages of road salt and alternative deicing chemicals. 

Type Advantages Disadvantages 

Road salt — Low cost ($30-40/ton) 

— Readily available 

— Impact on the environment 

— Corrosiveness 

Alternative 

deicing 

chemicals 

— Reduced corrosivity 

— Reduced impact on the environment 

— CaCl2 can be used in very low 

temperatures (-20oF) 

— Higher cost (from several hundred dollars 

per ton to several thousand per ton) 

— CMA starts to act at a slower rate than salt 

In general, alternatives to road salt are still being researched and tested throughout the 

Midwest and Northeast, but overall costs tend to be higher for these products. Less 

environmentally damaging products such as CMA, however, can be used selectively to 

protect sensitive areas like wetlands without dramatically increasing overall cost to the 

highway authority. 

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Management Measure 7: Bridges and Highways 

(3) Proper storage of deicing chemicals. Placing deicing chemicals in storage buildings 

minimizes the likelihood of polluting surface and ground waters with contaminated runoff 

and eliminates the economic loss from chemicals that are dissolved and washed away by 

precipitation. A permanent under-roof storage facility is the best way to protect chemicals 

from precipitation and runoff, but where this is not possible, salt piles and chemical 

containers should be stored on impermeable bituminous pads and covered with a tarp or other 

waterproof cover. 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

7.4 Information Resources 

The U.S. Geological Survey (USGS) and the Federal Highway Administration (FHWA) 

developed an online searchable bibliography of more than 2,600 pertinent references to be 

published in the catalog of available information that is being collected to characterize pollutant 

loadings and impacts attributable to highway storm water runoff. The catalog includes reports on 

highway-runoff water quality, urban/storm water issues, atmospheric deposition, and 

highway/urban runoff management practices from the USGS, FHWA, EPA, and state 

transportation agencies. The database can be accessed at 

http://ma.water.usgs.gov/fhwa/biblio/default.htm. 

The Local Technical Assistance Program Web site hosts a “Rural Roads Resources” page that 

includes a compendium of Web sites, manuals, videos, and other media pertaining to road design 

and maintenance. The site also hosts an email listserver pertaining to rural roads issues. The 

Local Technical Assistance Program Resources can be accessed at http://www.ltapt2.org/ by 

clicking “Resources.” 

The California Regional Water Quality Control Board produced the Erosion and Sediment 

Control Field Manual for the San Francisco Region in 1998. The document is available for a fee 

using an order form found at http://www.swrcb.ca.gov/stormwtr/orderform.html. 

The FHWA published a study by Dorman et al. (1996) called Detention and Overland Flow for 

Pollutant Removal from Highway Stormwater Runoff, which provides guidelines for the design 

of management measures for the removal of pollutants from highway storm water runoff. The 

guidelines are based on the results of field and laboratory studies to verify design procedures and 

assumptions and the review of other studies. For a copy of this document, contact FHWA’s 

Office of the Natural Environment by sending an email to environment@fhwa.dot.gov. 

Fisheries and Oceans Canada published Protecting Fish and Fish Habitat: Bridge Construction 

and Demolition, a fact sheet that details the hazards to aquatic life of bridge construction and 

demolition and recommends practices to reduce environmental damage. This document is 

available at http://www.dfo-mpo.gc.ca/canwaters-eauxcan/infocentre/guidelinesconseils/factsheets-feuillets/nfld/fact18_e.asp. 

In 1992, Northern Virginia Planning District Commission and Engineers Surveyors Institute 

produced the Northern Virginia BMP Handbook: A Guide to Planning and Designing Best 

Management Practices in Northern Virginia. This handbook is available for download at 

http://www.novaregion.org/pdf/NVBMP-Handbook.pdf. 

The Staff Transportation Board of the National Research Council produced a primer for a study 

entitled Environmental Impact of Construction and Repair Materials on Surface and Ground 

Waters. It is written in nontechnical language and explains how the test methods and supporting 

computer software can provide answers to questions about the environmental impact of new 

construction or the repair or rehabilitation of existing highways (NCHRP, 2000). Published 

reports from NCHRP are available from http://www.trb.org. 

The Transportation Research Board (TRB) published several studies that investigate the 

environmental impacts of activities related to transportation infrastructure. These publications 

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Management Measure 7: Bridges and Highways 

are available at http://www4.trb.org/trb/onlinepubs.nsf. For example, the National Cooperative 

Highway Research Program developed a synthesis of information on environmental management 

practices for highway and street maintenance. This report, entitled Best Management Practices 

for Environmental Issues Related to Highway and Street Maintenance, is available in hard copy 

from the Transportation Research Board’s bookstore (http://trb.org/bookstore/) for $30. Other 

titles include Highway Deicing: Comparing Salt and Calcium Magnesium Acetate (available 

electronically at http://trb.org/publications/sr/sr235.html or for $22 from the online bookstore); 

Assessing the Impacts of Bridge Deck Runoff Contaminants in Receiving Waters—Volume 

1:Final Report, available electronically at 

http://gulliver.trb.org/publications/nchrp/nchrp_rpt_474v1.pdf, and Assessing the Impacts of 

Bridge Deck Runoff Contaminants in Receiving Waters—Volume 2: Practitioner’s Handbook, 

available at http://gulliver.trb.org/publications/nchrp/nchrp_rpt_474v2.pdf. Publications pending 

as of spring 2005 include Guidelines for the Selection of Snow and Ice Control Materials To 

Mitigate Environmental Impacts (NCHRP Project 6-16) and Winter Highway Operations

(NCHRP topic 34-10), which reports on advances and new practices since TRB’s last guide for 

snow and ice control. Both publications will be available at http://www.trb.org. 

The TRB’s Environmental Stewardship Practices, Procedures, and Policies for Highway 

Construction and Maintenance (NCHRP 25-25(04)) includes numerous management practices in 

highway construction and maintenance. The guidance was developed from the literature, state 

transportation agency manuals and procedures, and the contributions of state departments of 

transportation and practitioners. The document serves as a guide to the development of 

environmental management systems and environmental strategic plans, both at the organizational 

level and in specific functional areas such as road construction, vegetation management, 

materials recycling, winter road maintenance, and many other topics. The document can be 

downloaded in PDF format from 

http://www4.trb.org/trb/crp.nsf/reference/boilerplate/Attachments/$file/25-25(4)_FR.pdf. 

TRB’s Evaluation of Best Management Practices and Low Impact Development for Highway 

Runoff Control, expected to be published in late 2004, includes a users’ guide for management 

practice selection, a design manual, and monitoring guidelines to evaluate and optimize the 

control of runoff from highways. Visit http://www.trb.org, and enter “NCHRP 25-20” into the 

search field to access the report. 

The Natural Resources Conservation Service (1992) published Soil Bioengineering for Upland 

Slope Protection and Erosion Reduction, which provides specifications for installing 

bioengineering practices to reinforce slopes and prevent erosion. This document is available for 

download at http://www.info.usda.gov/CED/ftp/CED/EFH-Ch18.pdf. 

The U.S. Department of Transportation’s (1995) Best Management Practices for Erosion and 

Sediment Control can be downloaded from the DOT’s online publications site at 

http://isddc.dot.gov/. 

The FHWA (1996) published the Manual of Practice for an Effective Anti-Icing Program: A 

Guide For Highway Winter Maintenance Personnel, which can guide maintenance personnel in 

developing a systematic and efficient practice for maintaining roads in the best condition 

possible during a winter storm. It describes the factors that should be understood and addressed 

 7-21 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

in an anti-icing program, with the recognition that development of a program must be based on 

the specific needs of the site or region. It focuses on weather information and materials and 

methods that will best address site conditions such as level of service, highway agency resources, 

climatological conditions, and traffic. The manual can be downloaded in HTML format from 

http://www.fhwa.dot.gov/reports/mopeap/mop0296a.htm. 

The Michigan Department of Transportation (1993) conducted a detailed study on the 

environmental effects and costs of using several deicing products, including salt, calcium 

magnesium acetate, an agricultural byproduct, a magnesium chloride product, calcium chloride, 

a type of concrete pavement, and sand. The study can be accessed at 

http://www.michigan.gov/documents/toc-deice_51451_7.pdf. More information on alternative 

deicers can be found at http://www.betterroads.com/articles/prod801.htm, 

http://www.forester.net/sw_0106_deicing.html, and 

http://www.wsdot.wa.gov/partners/pns/htm/resources.htm. 

The Pacific Northwest Snowfighters Association Web site 

(http://www.wsdot.wa.gov/partners/pns/) provides resources pertaining to deicing and anti-icing 

products and practices, such as a list of approved products, deicing specifications, a fact sheet on 

magnesium chloride, and testing methods and protocols for deicing products (Washington State 

Department of Transportation, 2002). 

Funded by EPA, the Composting Council Research and Education Foundation (CCREF), in 

conjunction with the United States Composting Council (USCC), developed Compost Use on 

State Highway Applications to promote compost use on state and local roadside applications. Its 

goal is to provide individuals and organizations—namely, roads and highways staff, policy 

makers, product specifiers, project designers and engineers, environmental officers, landscapers, 

and other interested parties—involved in the maintenance and management of roadsides and 

highways, with the tools necessary to use composted products to meet their specific project 

requirements. The document is available for download in PDF format at 

http://www.epa.gov/epaoswer/non-hw/compost/highway/. 

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Management Measure 7: Bridges and Highways 

7.5 References 

Appleman, B.R. 1992. NCHRP Synthesis of Highway Practice 176: Bridge Paint: Removal, 

Containment and Disposal. Transportation Research Board, National Research Council, 

Washington, DC. 

Bannerman, R., K. Baun, M. Bohn, P.E. Hughes, and D.A. Graczyk. 1983. Evaluation of Urban 

Nonpoint Source Pollution Management in Milwaukee County, Wisconsin, Volume I. PB 

84-114164. U.S. Environmental Protection Agency, Water Planning Division. 

Chollar, B. 1996. A Revolution in Winter Maintenance. U.S. Department of Transportation, 

Federal Highway Administration, McLean, VA. 

Crisitina, C. J. Tramonte, and J.J. Sansalone. 2000. A Granulometry-Based Selection 

Methodology for Separation of Traffic-Generated Particles in Highway Snowmelt Runoff. 

Louisiana State University, Department of Civil and Environmental Engineering, Baton 

Rouge, LA. 

Dalton, Dalton and Newport/URS. 1985. Investigations of Impacts of Selected Highway 

Maintenance Practices on Water Quality. Report No. FHWA/RD-85/058. 

Delaware County Departments of Planning and Public Works. 2003. Stormwater Management: 

Delaware County Action Plan. Version 1. 

Dorman, M.E., J. Hartigan, R.F. Steg, and T. Quasebarth. 1996. Retention, Detention and 

Overland Flow for Pollutant Removal From Highway Stormwater Runoff. Vol. 1 

Research Report. FHWA/RD 89/202. Federal Highway Administration, Washington, DC. 

Federal Highway Administration. 1996. Manual of Practice for an Effective Anti-Icing Program: 

A Guide For Highway Winter Maintenance Personnel. Publication No. FHWA-RD-95-

202. 

Hayward, J.M.R., C.G. Ingersoll, D.W. Whites, and E.E. Little. 2002. Toxicity Assessment of 

Sediments from the Barton Springs Watershed, Austin, Texas, USA. Draft. U.S. 

Geological Survey, Columbia Environmental Research Center, Columbia, MO. 

Kayhanian. M., J. Johnston, H. Yamaguchi and S. Borroum. 2001. CALTRANS Storm Water 

Management Program. Stormwater 2(2): 52-67. 

Lehner, P., G. P. Aponte Clark, D.M.Cameron and A.G. Frank. 1999. Stormwater Strategies: 

Community Responses to Runoff Pollution. Natural Resources Defense Council. 

http://www.nrdc.org/water/pollution/storm/stoinx.asp. Accessed August 12, 2003. 

Mahler, B.J., and P.C. Van Metre. 2004. Parking Lot Sealants: An Unrecognized Source of 

Particulate PAH in Urban Runoff. Paper No. 65-8 from the Geological Society of 

America Annual Meeting, November 7–10, 2004, Denver, CO. 

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Michigan Department of Transportation. 1993. The Use of Selected Deicing Materials on 

Michigan Roads: Environmental and Economic Impacts. Prepared by Public Sector 

Consultants, Inc. Lansing, MI, for the Michigan Department of Transportation, 

Lansing, MI. 

Minton, G.R., B. Lief, and R Sutherland. 1998. High efficiency sweeping or “clean a street, save 

a salmon!” http://www.schwarze.com/sweepers/ev/mintonvol4No4.html. Accessed 

August 8, 2001. 

National Cooperative Highway Research Program (NCHRP). 1999. Assessment of Impacts of 

Bridge Deck Runoff Contaminants on Receiving Waters. Research Results Digest. 

Number 235. National Research Council, Transportation Research Board, National 

Cooperative Highway Research Program, Washington, DC. 

National Cooperative Highway Research Program (NCHRP). 2000. NCHRP Report 443: 

Primer: Environmental Impact of Construction and Repair Materials on Surface and 

Ground Waters. National Cooperative Highway Research Program, National Research 

Council, Washington, DC. 

Newberry, G.P., and D.R.Yonge. 1996. The Retardation of Heavy Metals in Stormwater Runoff 

by Highway Grass Strips. Report no. WA-RD-404.1. Prepared for Washington State 

Department of Transportation, Olympia, WA. 

Ohio Department of Transportation (ODOT). No date. Ohio Department of Transportation OnLine Bridge Maintenance Manual: Preventative Maintenance/Repair Guidelines for 

Bridges and Culverts. http://www.dot.state.oh.us/preventivemaintenance/. Accessed July 

21, 2004. 

Pitt, R. 1979. Demonstration of Nonpoint Pollution Abatement through Improved Street 

Cleaning Practices. EPA-600-2-79-161. U.S. Environmental Protection Agency, 

Cincinnati, OH. 

Pitt, R. 1985. Characterizing and Controlling Urban Runoff through Street and Sewerage 

Cleaning. EPA-600-S2-85-038. U.S. Environmental Protection Agency, Storm and 

Combined Sewer Program, Risk Reduction Engineering Laboratory. Cincinnati, OH. 

Pitt, R. 2001. Stormwater Management for Highway Projects. Symposium on the Pollution of 

Water Sources from Road Run-off. March 19, Tel Aviv University, Israel. 

Reel, M. 2004, February 11. Tumors prevalent in Anacostia’s fish. The Washington Post, p. B1. 

Sansalone, J.J., and D.W. Glenn III. 2000. Temporal Variations in Heavy Metal Partitioning and 

Loading in Urban Highway Pavement Sheet Flow: Implications for In Situ Treatment 

Design. Transportation Research Record 1720 (00-0354):100–111. 

Sansalone, J.J., and D.W. Glenn III. 2002a. Accretion of Pollutants in Roadway Snow Exposed 

to Urban Traffic and Winter Storm Maintenance Activities—Part I. Journal of 

Environmental Engineering 128(2). 

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Management Measure 7: Bridges and Highways 

Sansalone, J.J., and D.W. Glenn III. 2002b. Accretion and Partitioning of Heavy Metals 

Associated with Urban Snow—Part II. Journal of Environmental Engineering 128(2). 

Sansalone, J.J., and D.W. Glenn III. Unpublished. Physical and Chemical Characteristics of 

Urban Roadway Snow Residuals Generated from Traffic Activities—Part III. 

Sansalone, J.J., and S.G. Buchberger. 1997. Partitioning and First Flush of Metals in Urban 

Roadway Storm Water. Journal of Environmental Engineering 123(2):134–143. 

Sansalone, J.J., and T. Tribouillard. 1999. Variation in Characteristics of Abraded Roadway 

Particles as a Function of Particle Size: Implications for Water Quality and Drainage. 

Transportation Research Record 1690(99-0552):153–163. 

Sansalone, J.J., J.M. Koran, J.A. Smithson, and S.G. Buchberger. 1998. Physical Characteristics 

of Urban Roadway Solids Transported During Rain Events. Journal of Environmental 

Engineering May:427–440. 

Schueler , T.R. 1987. Controlling Urban Runoff: A Practical Manual for Planning and 

Designing Urban BMPs. Metropolitan Washington Council of Governments, 

Washington, DC. 

Schwarze Industries. 2004. Virginia test further documents pickup of high efficiency sweepers. 

American Sweeper 8(1). 

Shepp, D.L. 1996. Petroleum Hydrocarbon Concentrations Observed in Runoff From Discrete, 

Urbanized Automotive-Intensive Land Uses. In Proceedings of Watershed 96: Moving 

Ahead Together, Baltimore, MD, June 8–12, 1996. 

Sutherland, R.C., and S.L. Jelen. 1997. Contrary to conventional wisdom, street sweeping can be 

an effective BMP. In Advances in Modeling the Management of Stormwater Impacts, ed. 

W. James, pp. 179–190. Computational Hydraulics International, Guelph, ON. 

Sutherland, R.C., S.L. Jelen, and G. Minton. 1998. High efficiency sweeping as an alternative to 

the use of wet vaults for stormwater treatment. In Advances in Modeling the Management 

of Stormwater Impacts, ed. W. James, pp. 351–372. Computational Hydraulics 

International, Guelph, ON. 

Transportation Research Board. 1991. Highway Deicing: Comparing Salt and Calcium 

Magnesium Acetate. Special Report 235. National Research Council, Transportation 

Research Board, Washington, DC. 

Transportation Research Board. 2002a. Assessing the Impacts of Bridge Deck Runoff 

Contaminants in Receiving Waters—Volume 1:Final Report. 

http://gulliver.trb.org/publications/nchrp/nchrp_rpt_474v1.pdf. Accessed June 30, 2003. 

Transportation Research Board. 2002b. Assessing the Impacts of Bridge Deck Runoff 

Contaminants in Receiving Waters—Volume 2: Practitioner’s Handbook. 

http://gulliver.trb.org/publications/nchrp/nchrp_rpt_474v2.pdf. Accessed June 30, 2003. 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

U.S. Department of Agriculture (USDA). 1992. Soil Bioengineering for Upland Slope Protection 

and Erosion Reduction. Part 650, Chapter 18 in National Engineering Field Handbook. 

Natural Resources Conservation Service, U.S. Department of Agriculture, Washington, 

DC. 

U.S. Department of Transportation (USDOT). 1996. Evaluation and Management of Highway 

Runoff Water Quality. Publication No. FHWA-PD-96-032. U.S. Department of 

Transportation, Federal Highway Administration, Washington, DC. 

U.S. Environmental Protection Agency (USEPA). 2001. National Management Measures 

Guidance to Control Nonpoint Source Pollution from Marinas and Recreational Boating. 

EPA 841-B-01-005. U.S. Environmental Protection Agency, Office of Water, 

Washington, DC. 

Van Metre, P.C., B.J. Mahler, and E.T. Furlong. 2000. Urban Sprawl Leaves Its PAH Signature. 

Environmental Science and Technology 34:4064–4070. 

Washington State Department of Transportation. 2002. Pacific Northwest Snowfighters. 

http://www.wsdot.wa.gov/partners/pns/. Last updated June 18, 2002. Accessed June 28, 

2002. 

Young, G.K., Stein, S., Cole, P., Kammer, T., Graziano, F., and Bank, F. 1996. Evaluation and 

Management of Highway Runoff Water Quality. Publication No. FHWA-PD-96-032. 

7-26 
Management Measure 8: Construction Site Erosion, Sediment, and Chemical Control 

MANAGEMENT MEASURE 8 

CONSTRUCTION SITE EROSION, 

SEDIMENT, AND CHEMICAL CONTROL 

8.1 Management Measure 

Plan, design, and operate construction site land disturbance activities such that: 

— An approved erosion and sediment control plan or similar administrative document that 

contains erosion and sediment control provisions is prepared and implemented prior to 

land disturbance. 

— Erosion is reduced and, to the extent practicable, sediment is retained on-site during and 

after construction. 

— Good housekeeping practices are used to prevent off-site transport of waste material and 

chemicals. 

— The application and generation of pollutants, including chemicals are minimized. 

8.2 Management Measure Description and Selection 

8.2.1 Description 

This management measure is intended to reduce the amount of sediment generated from 

construction sites (erosion control) and reduce the off-site transport of sediment and 

construction-related chemicals (sediment and chemical control). This measure is intended to 

work in concert with the Watershed Protection, New Development Runoff Treatment, and Site 

Development Management Measures in a comprehensive watershed management program 

framework. 

Several pollutants of concern are associated with construction activities, including the following: 

sediment; pesticides; fertilizers used for vegetative stabilization; petrochemicals (oils, gasoline, 

and asphalt degreasers); construction chemicals such as concrete products, sealers, and paints; 

wash water associated with these products; paper; wood; garbage; and sanitary waste 

(Washington State Department of Ecology, 1991). 

The variety of pollutants present at a site and the severity of their effects are dependent on a 

number of factors: 

− The nature of the construction activity. During the clearing and grading stage, sediment is 

likely to be the primary pollutant of concern since few other materials are present, 

whereas during the building phase, concrete wash, paints, varnishes, stucco, and other 

materials are being used on a daily basis, increasing the likelihood of spills. 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

− The physical characteristics of the construction site. Most pollutants generated at 

construction sites are carried to surface waters by runoff. Therefore, the factors that affect 

runoff volume, such as the amount, intensity, and frequency of rainfall; soil infiltration 

rates; surface roughness; slope length and steepness; and size of the denuded area, also 

affect pollutant loadings. 

− The proximity of surface waters to the nonpoint pollutant source. As the distance 

separating pollutant-generating activities from surface waters decreases, the likelihood of 

water quality impacts increases. 

The following section is an expanded discussion of the pollutants of concern that can be 

generated by and released from construction activities. 

8.2.1.1 Sediment 

Runoff from construction sites is by far the largest source of sediment in urban areas under 

development. Soil erosion removes more than 90 percent of sediment by weight in urbanizing 

areas where most construction activities occur (Canning, 1988). Table 8.1 illustrates some of the 

sediment loading rates associated with construction activities across the United States. As shown 

in Table 8.1, erosion rates from natural areas such as undisturbed forested lands are typically less 

than 1 ton/acre/year, whereas erosion from construction sites ranges from 7.2 to 500 

tons/acre/year. 

Loss of sediment can cause impacts both on and off the construction site. On-site loss of soil 

reduces or eliminates the remaining soil’s ability to provide nutrients, regulate water flow, and 

protect plants. Losses of nutrients and nutrient-holding capacity result in a less-fertile 

environment for lawns and plants. Lost organic matter also results in increased soil density and 

compaction, which can reduce the available water-holding capacity on-site. These reductions 

result in poorer plant growth and reduced infiltration of fertilizers and pesticides, which can 

contribute to the transport of these chemicals by runoff into nearby lakes and streams. Finally, 

organic matter is a food source and habitat for beneficial microorganisms and invertebrates. If 

organic matter is lost due to erosion, the soil’s natural ability to combat outbreaks of pests and 

diseases is reduced (SQI, 2000). 

Eroded sediment from construction sites causes many problems in coastal areas, including 

adverse impacts on water quality, critical habitats, submerged aquatic vegetation beds, 

recreational activities, and navigation (APWA, 1991). Water quality impacts include unwanted 

biological growth caused by excess nitrogen and phosphorus, and increased turbidity. Eroded 

sediment can also build up in stream channels and lower flow capacity, resulting in more 

frequent flooding in areas that never flooded or rarely flooded in the past. Reducing the 

incidence of flooding can also be beneficial in alleviating the financial burden of cleaning up 

sediment-damaged areas (SQI, 2000). Excessive erosion and sedimentation also can reduce the 

capacity of reservoirs. 

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Management Measure 8: Construction Site Erosion, Sediment, and Chemical Control 

Table 8.1: Erosion and sediment associated with construction (USEPA, 1993). 

Location Problem Reference 

Franklin County, 

Florida 

Sediment yield (ton/ac/yr): 

Forest < 0.5 

Rangeland < 0.5 

Tilled 1.4 

Construction site 30 

Established urban < 0.5 

Franklin County, 

Florida, 1987 

Wisconsin Erosion rates range from 30 to 200 ton/ac/yr (10 to 20 times 

those of cropland). 

Wisconsin Legislative 

Council, 1991 

Washington, DC Erosion rates range from 35 to 45 ton/ac/yr (10 to 100 times 

greater than agriculture and stabilized urban land uses). 

MWCOG, 1987 

Anacostia River Basin, 

Maryland and 

Washington, DC 

Sediment yields from portions of the Anacostia Basin have 

been estimated at 75,000 to 132,000 ton/yr. Total basin 

acreage = 112,640 acres. 

U.S. Army Corps of 

Engineers, 1990 

Anacostia River Basin, 

Maryland and 

Washington, DC 

Erosion rates range from 7.2 to 100.8 ton/ac/yr. Total basin 

acreage = 112,640 acres. 

USGS, 1978 

Washington Erosion rates range from 50 to 500 ton/ac/yr. Natural 

erosion rates from forests or well-sodded prairies are 0.01 to 

1.0 ton/ac/yr. 

Washington State 

Department of Ecology, 

1989 

Alabama 

North Carolina 

Louisiana 

Oklahoma 

Georgia 

Texas 

Tennessee 

Pennsylvania 

Ohio 

Kentucky 

1.4 million tons eroded per year. 

6.7 million tons eroded per year. 

5.1 million tons eroded per year. 

4.2 million tons eroded per year. 

3.8 million tons eroded per year. 

3.5 million tons eroded per year. 

3.3 million tons eroded per year. 

3.1 million tons eroded per year. 

3.0 million tons eroded per year. 

3.0 million tons eroded per year. 

Woodward Clyde, 1991 

8.2.1.2 Pesticides 

Insecticides, rodenticides, and herbicides are used on construction sites to improve human health 

conditions, reduce maintenance and fire hazards, and curb the growth of weeds and woody 

plants. Common pesticides employed include synthetic, relatively water-insoluble chlorinated 

hydrocarbons, organophosphates, carbamates, and pyrethrins. Over-application of pesticides on 

Results indicate that small construction sites are potential sources of high amounts of erosion and that 

sediment loads from the active construction phase are significantly higher than those during the 

preconstruction and postconstruction periods. These sediment loads were dramatically reduced when 

mulching and seeding were used to control erosion. The results of this study support the need for 

erosion control plans for small construction sites. 

Soil Erosion from Two Small Construction Sites in Dane County, Wisconsin 

Most construction regulations require sites with more than 5 acres disturbed to have some type of 

erosion control plan. Sites that are less than 5 acres typically require minimal erosion control 

measures. To evaluate the significance of erosion on sites less than 5 acres as a source of sediment 

to surface waters, two small construction sites (less than 5 acres each) in Dane County, Wisconsin, 

were studied (USGS, 2000). 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

revegetated areas can lead to contamination of soils and subsequent contamination of surface 

water and ground water. The use of pesticides is controlled by federal or state regulations, such 

as the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) of 1996. 

8.2.1.3 Petroleum products 

Petroleum products used during construction include fuels and lubricants for vehicles, power 

tools, and general equipment maintenance. Specific petroleum pollutants include gasoline, diesel 

oil, kerosene, lubricating oils, and grease. Asphalt paving can be particularly harmful because it 

releases various oils after application until fully cured (NCHRP, 2000). 

8.2.1.4 Fertilizers 

Fertilizers are used on construction sites when revegetating graded or disturbed areas. Fertilizers 

contain nitrogen and phosphorus, which in large doses can adversely affect surface water quality, 

causing eutrophication. 

8.2.1.5 Solid wastes 

Trees and shrubs removed during land clearing contribute to the load of solid wastes generated 

during construction activities. Other common wastes are wood and paper from packaging and 

building materials, scrap metals, sanitary wastes, rubber, plastic and glass, and masonry and 

asphalt products. Improper disposal of food containers, paint canisters, cigarette packages, 

leftover food, and aluminum foil also contributes solid wastes to the construction site. 

8.2.1.6 Construction chemicals 

There are many sources of chemicals at construction sites. For example, chemicals such as 

paints, acids for cleaning masonry surfaces, cleaning solvents, asphalt products, soil additives 

used for stabilization, and concrete-curing compounds are used on construction sites and can be 

carried off in runoff. Other pollutants, such as wash water from concrete mixers, acid and 

alkaline solutions from exposed soil or rock, and alkaline-forming natural elements, can also be 

present and contribute to nonpoint source pollution. Improperly stored construction materials, 

such as creosote- or pressure-treated lumber or solvents, can lead to leaching of pollutants to 

surface water and ground water. People disposing of construction chemicals should follow all 

applicable state and local laws. Some chemicals may need to be disposed of by a licensed waste 

management firm. 

Improper fueling and servicing of vehicles can lead to dumping of significant quantities of 

petroleum products onto the ground. These pollutants can then be washed off the site in urban 

runoff, even when proper erosion and sediment controls are in place. Pollutants carried in 

solution in runoff or attached to sediments may not be adequately controlled by erosion and 

sediment control practices (Washington Department of Ecology, 1991). Oils, waxes, and waterinsoluble pesticides can form surface films on water and solid particles. Oil films can also 

concentrate water-soluble insecticides. Once present in runoff, these pollutants can be nearly 

impossible to control other than by the use of very costly water treatment facilities (Washington 

Department of Ecology, 1991). 

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Management Measure 8: Construction Site Erosion, Sediment, and Chemical Control 

In addition to spill prevention, one of the best methods to control petroleum pollutants is to retain 

the sediments that have come into contact with these chemicals through use of erosion and 

sediment control practices. Improved maintenance and storage facilities reduce the chance of 

contaminating a construction site. One of the greatest concerns related to the use of petroleum 

products is the method for waste disposal. Dumping petroleum product wastes into sewers and 

other drainage channels is illegal and could result in fines or site closure. 

8.2.1.7 Contaminated soils 

Contaminated soils can be encountered during excavation activities that uncover previously 

known or unknown site contamination. New contamination also can result from a spill or leak of 

a hazardous material used at the construction site (e.g., a release from a material or waste storage 

area). If previously unknown contamination is encountered, its nature should be determined. 

Sampling and analysis will be required to determine what types of contaminants are present and, 

therefore, how the contaminated soil needs to be handled. 

8.2.2 Management Measure Selection 

This management measure was selected to reduce sediment mobilization and transport off of the 

construction site area. This management measure was selected because construction activities 

have the potential to increased loadings of toxic substances and nutrients in water bodies. 

Various states and local governments regulate the control of sediment and chemicals on 

construction sites through spill prevention plans, erosion and sediment control plans, or other 

administrative devices. The practices provided herein are commonly used and well-described in 

handbooks and guidance manuals, and they have been shown to be both economical and 

effective. 

The measures were selected for the following reasons: 

— Setting numeric load reduction goals for construction site pollutant loadings is generally 

not practical; sediment and other pollutant loadings from exposed areas vary greatly, and 

some sediment loss is usually inevitable. 

— Erosion and sediment control plans (ESCs) and specifications are required by many state 

and local governments to accomplish the performance goals for this measure. These ESC 

plans contain specifications and designs for the proper selection and placement of ESC 

practices. These practices have been proven to be effective when implemented at 

construction sites. 

— Current procedure typically relies on a set of practices selected based on site-specific 

conditions. 

— The combined effectiveness of erosion and sediment controls in systems is not easily 

quantified. 

— An ESC plan is necessary to provide details regarding the selection, use, inspection, and 

maintenance of management practices to ensure they are effective in controlling erosion 

and preventing off-site discharges of sediment. 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

— No deposit or discharge of sediment onto adjacent properties or into waterbodies. 

— No degradation of waterbodies due to the removal of vegetation. 

— No discharge or runoff containing construction-related contaminants into the city's runoff 

conveyance system or related natural resources. 

— No deposit of construction-related material exceeding 0.5 cubic foot for every 1,000 square 

feet of lot size onto public rights-of-way and private streets and into the city's runoff 

conveyance system and related natural resources. 

Eugene, Oregon’s goals for erosion and sediment control on construction sites 

The City of Eugene, Oregon, requires that, to the maximum extent feasible, management practices 

that meet a specified set of outcomes be employed at construction sites, including the following 

(NRDC, 1999): 

8.3 Management Practices 

8.3.1 Erosion and Sediment Control Programs 

8.3.1.1 Prepare erosion and sediment control plans 

In many municipalities, erosion and sediment control plans are required under ordinances 

enacted to protect water resources (Table 8.2). These plans describe how a contractor or 

developer will reduce soil erosion and contain and treat runoff that is carrying eroded sediments. 

Plans typically include descriptions and locations of soil stabilization practices, perimeter 

controls, and runoff treatment facilities that will be installed and maintained before and during 

construction activities. In addition to special area considerations, the full ESC plan review 

inventory should include: 

— Topographic and vicinity maps 

— Site development plan 

— Construction schedule 

— Erosion and sedimentation control plan drawings 

— Detailed drawings and specifications for practices 

— Design calculations 

— Vegetation plan 

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Management Measure 8: Construction Site Erosion, Sediment, and Chemical Control 

Table 8.2: ESC plan requirement for selected states (Adapted from USEPA, 1993; 

Environmental Law Institute, 1998). 

State General Requirements for ESC Plan 

Delaware ESC plans required for sites over 5,000 ft2. Temporary or permanent stabilization must occur 

with 14 days of disturbance. 

Florida ESC plans required on all sites that need a runoff management permit. 

Georgia ESC plan required for all land-disturbing activities. 

Indiana ESC plan required for sites over 5 acres. 

Maine ESC plans required for sites adjacent to a wetland or water body. Stabilization must occur at 

completion or if no construction activity is to occur for seven days. If temporary stabilization 

is used, permanent stabilization must be implemented within 30 days. 

Maryland ESC plans required for sites over 5,000 ft2 or 100 yd3. 

Michigan ESC plans required for sites over 1 acre or within 500 ft of a water body. Permanent 

stabilization must occur within 15 days of final grading. Temporary stabilization is required 

within 30 days if construction ceases. 

Minnesota ESC plans required for land development over 1 acre. 

New Jersey ESC plans required for sites over 5,000 ft2. 

North Carolina ESC plans required for sites over 1 acre. Controls must retain sediment on-site. Stabilization 

must occur within 30 days of completion of any phase of development. 

Ohio ESC plans required for sites over 5 acres. Permanent stabilization must occur within seven 

days of final grading or when there is no construction activity for 45 days. 

Oklahoma ESC plans required for sites over 5 acres. 

Pennsylvania All earth disturbance activities require implementation and maintenance of ESC practices to 

minimize the potential for accelerated erosion and sedimentation. Written ESC plans are 

required for all earth disturbance activities 5,000 square feet or greater. Upon completion of 

an earth disturbance activity or any stage or phase of an activity, the site shall be immediately 

seeded, mulched, or otherwise protected from accelerated erosion and sedimentation. 

South Carolina ESC plans required for all sites unless specifically exempted. Perimeter controls must be 

installed. Temporary or permanent stabilization is required for topsoil stockpiles and all other 

areas within seven days of disturbance. 

Virginia For areas within the jurisdiction of the Chesapeake Bay Preservation Act, no more land is to 

be disturbed than necessary for the project. Indigenous vegetation must be preserved to the 

greatest extent possible. 

Washington ESC provisions are incorporated into the state runoff management plan. 

Wisconsin ESC plans required for all sites over 4,000 ft3. Temporary or permanent stabilization is 

required within seven days. 

Brown and Caraco (1997) identified several general objectives that should be addressed in an 

effective ESC plan: 

— Minimize clearing and grading. Clearing and grading should occur only where absolutely 

necessary to build and provide access to structures and infrastructure. This approach 

reduces earth-working and ESC control costs by as much as $5,000 per acre (Schueler, 

1995). Clearing should be done immediately before construction, rather than leaving soils 

exposed for months or years (SQI, 2000).

— Protect waterways and stabilize drainageways. All natural waterways within a 

development site should be clearly identified before construction activities begin. 

Clearing should generally be prohibited in or adjacent to waterways. Sediment control 

practices such as check dams may be needed to stabilize drainageways and retain 

sediment on-site. 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

— Phase construction to limit soil exposure. Construction phasing is a process by which 

only a portion of the site is disturbed at any one time to complete the needed building in 

that phase. Other portions of the site are not cleared and graded until exposed soils from 

the earlier phase have been stabilized and the construction is nearly completed.

— Stabilize exposed soils immediately. Seeding or other stabilization practices should occur 

as soon as possible after grading. In colder climates, a mulch cover is needed to stabilize 

the soil during the winter months when grass does not grow or grows poorly.

— Protect steep slopes and cuts. Wherever possible, clearing and grading of existing steep 

slopes should be completely avoided. If clearing cannot be avoided, practices should be 

implemented to prevent runoff from flowing down slopes.

— Install perimeter controls to filter sediments. Perimeter controls are used to retain 

sediment-laden runoff or filter it before it exits the site. The two most common perimeter 

control options are silt fences and earthen dikes or diversions.

— Employ advanced sediment-settling controls. Traditional sediment basins are limited in 

their ability to trap sediments because fine-grained particles tend to remain suspended 

and the design of the basins themselves is often simplistic. Sediment basins can be 

designed to improve trapping efficiency through the use of perforated risers; better 

internal geometry; the installation of baffles, skimmers, and other outlet devices; gentler 

side slopes; and multiple-cell construction (see section 3.3: Sediment Control Practices). 

ESC plans ensure that provisions for control measures are incorporated into the site planning 

stage of development. They also help to reduce the incidence of erosion and sediment problems, 

and improve accountability if a problem occurs. An effective plan for runoff management on 

construction sites controls erosion, retains sediments on-site to the extent practicable, and 

reduces the adverse effects of runoff. Climate, topography, soils, drainage patterns, and 

vegetation affect how erosion and sediment should be controlled on a site (Washington State 

Department of Ecology, 1989). 

An effective ESC plan includes both structural and nonstructural controls. Nonstructural controls 

address erosion control by decreasing erosion potential, whereas structural controls are both 

preventive and mitigative because they control erosion and sediment movement. Typical 

nonstructural erosion controls include: 

— Plans and designs to minimize disruption of the natural features (drainage, topography, 

vegetative cover); 

— Phased grading to minimize the area of bare soil exposed at any given time; 

— Scheduling of activities during the time of year with the least erosion potential; and 

— Stabilization, e.g., mulching and seeding of exposed areas. 

Structural controls include: 

— Perimeter controls; 

— Sediment basins and traps; 

— Silt fences or filter fabrics; 

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Management Measure 8: Construction Site Erosion, Sediment, and Chemical Control 

— Stream crossing areas for natural and man-made areas; and 

— Stabilization of cut-and-fill slopes caused by construction activities. 

Some erosion and soil loss is unavoidable during land-disturbing activities. Although proper 

siting and design help prevent development of areas prone to erosion, construction activities 

invariably result in conditions where erosion can occur. To reduce the adverse impacts associated 

with construction, the construction management measure was written to promote the use of a 

system of nonstructural and structural erosion and sediment controls for incorporation into an 

ESC plan. Erosion controls reduce the amount of sediment transported off-site, thereby reducing 

the need for sediment controls and lowering overall costs. When erosion controls are used in 

conjunction with sediment controls, the size of the sediment control structures and associated 

maintenance may be reduced, decreasing overall treatment costs (SWRPC, 1991). 

8.3.1.2 Provide education and training opportunities for construction personnel 

One of the most important factors determining whether erosion and sediment controls will be 

properly installed and maintained on a construction site is the knowledge and experience of the 

contractor. Many communities require certification for key on-site employees who are 

responsible for implementing the ESC plan. Certification can be accomplished through 

municipally sponsored training courses. Municipalities also can hold mandatory preconstruction 

or pre-wintering meetings and conduct regular and final inspection visits to transfer information 

to contractors (Brown and Caraco, 1997). Information that should be covered in training courses 

and meetings includes the importance of ESC practices for water quality protection; developing 

The Maine Department of Environmental Protection offers the Voluntary Contractor Certification 

Program (VCCP), which is a nonregulatory, incentive-driven program to broaden the use of effective 

erosion control techniques. The VCCP is open to any contractor who is involved with soil disturbance 

activities, including filling, excavating, landscaping, and other types of earthworks. For initial 

certification, the program requires attendance at two 6-hour training courses and the successful 

completion of a construction site evaluation. To maintain certification, a minimum of one 4-hour 

continuing education course within every 2-year period thereafter is required. Local soil and water 

conservation district personnel will complete construction site evaluations during the construction 

season. Certifications are valid until December 31 of the second year after issuance. Certification 

entitles the holder to advertise services as a "DEP Certified Contractor" (MDEP, 1999). More 

information about this program is provided on the MDEP Web site at janus.state.me.us/dep/blwq/ 

training/is-vccp.htm.

Delaware requires that at least one person on any construction project be formally certified. The 

Delaware program requires certification for any foreman or superintendent who is in charge of on-site 

clearing and land-disturbing activities for sediment and runoff control associated with a construction 

project. Responsible personnel are required to obtain certification by completing a Department of 

Natural Resources and Environmental Control-sponsored or approved training program. All applicants 

seeking approval of a sediment and runoff plan must certify that all personnel involved in the 

construction project will have a certificate of attendance at a Department-sponsored or approved 

training course before initiation of any land-disturbing activity (Delaware DNREC, no date). A 

description of this certification requirement is provided at the DNREC Web site at 

www.dnrec.state.de.us/newpages/ssregs14.htm. 

Contractor/Developer Certification Programs in Delaware and Maine

8-9 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

— Inspecting projects and facilities for compliance with erosion, sediment control, and waste 

management requirements. 

— Providing classroom and on-the job training and consulting. 

— Publishing a monthly storm water bulletin for employees and state and local regulatory 

agencies. 

— Reviewing storm water pollution prevention plans for construction sites. 

— Providing feedback on how well methods work and what improvements could be made to 

improve performance. 

— Preparing specialized training materials, such as videos and model pollution prevention plans. 

— Providing input for storm water guidance manuals and water pollution control specifications for 

highway design and construction. 

The California Department of Transportation’s Storm Water Management Plan 

The California Department of Transportation (Caltrans) operates one of the most comprehensive 

storm water drainage systems in the United States. It has recently undertaken a multifaceted program 

to investigate and address pollutant load reduction in California’s storm water runoff. To improve storm 

water management, Caltrans created the Storm Water Task Force (SWTF) to monitor, train, and 

educate its employees and hired contractors about pollution prevention measures. The SWTF’s goals 

are to raise awareness and to change work habits so that Caltrans employees can more effectively 

address storm water issues. The SWTF uses the following techniques to accomplish their goals 

(Borroum et al., 2000): 

and implementing ESC plans; the importance of proper installation, regular inspection, and 

diligent maintenance of ESC practices; and recordkeeping for inspections and maintenance 

activities. Training and education should logically extend to all on-site personnel responsible for 

implementing a construction runoff control plan. 

8.3.1.3 Establish plan review and modification procedures 

ESC plans should be flexible to account for unexpected events that occur after the plans have 

been approved, including: 

— Discrepancies between planned and as-built grades; 

— Weather conditions; 

— Altered drainage; and 

— Unforeseen construction requirements. 

Changes to an ESC plan should be made based on regular inspections that identify whether the 

ESC practices were appropriate or properly installed or maintained. 

8.3.1.4 Assess ESC practices after storm events 

Inspecting an ESC practice after storm events shows whether the practice was installed or 

maintained properly. Such inspections also help determine whether a practice requires cleanout, 

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Management Measure 8: Construction Site Erosion, Sediment, and Chemical Control 

repair, reinforcement, or replacement with a more appropriate practice. Inspecting after storms is 

the best way to ensure that ESC practices remain in place and effective at all times during 

construction activities. 

8.3.1.5 Ensure ESC plan implementation 

Because funding for ESC programs is not always dedicated, budgetary and staffing constraints 

may thwart effective program implementation. Brown and Caraco (1997) recommend several 

management techniques to ensure that ESC programs are properly administered: 

— Local leadership committed to the ESC program; 

— Redeployment of existing staff from the office to the field or training room; 

— Cross-training of local review and inspection staff; 

— Submission of erosion prevention elements for early planning review; 

— Prioritization of inspections based on erosion risk; 

— Requirement of designers to certify the initial installation of ESC practices; 

— Investment in contractor certification and private inspector programs; 

— Use of public-sector construction projects to demonstrate effective ESC controls; 

— Enlistment of the talents of developers and engineering consultants in the ESC program; 

and 

— Revision and update of the local ESC manual. 

To facilitate public participation, a hotline can be established to allow for citizen “monitoring” 

and reporting of any illicit discharges. Materials should be distributed or public service 

announcements made to advertise the hotline. 

An allowance item that acts as an additional "insurance policy" for complying with the erosion 

and sediment control plan also can be added to bid or contract documents (Deering, 2000a). This 

allowance covers costs to repair storm damage to erosion and sediment control measures as 

specified in the erosion and sediment control plan. This allowance does not cover storm damage 

to property that is not related to the erosion and sediment control plan, because this would be 

covered under traditional liability insurance. Damage caused by severe and continuous rain, 

windblown objects, fallen trees or limbs, or high-velocity, short-term rain on steep slopes and 

existing grades would be covered by the allowance, as would deterioration from exposure to the 

elements or excessive maintenance for silt removal. The contractor is responsible for complying 

with the erosion and sediment control plan by properly implementing and maintaining all 

specified measures and structures. The allowance does not cover damage to practices caused by 

improper installation or maintenance. 

A study by University of North Carolina researchers measured the effects of erosion and 

sediment control regulations, inspections, and enforcement on stream biological condition at 17 

construction sites in central North Carolina (Reice and Andrews, 2000). At each site, upstream, 

downstream, and at-site samples were taken before construction began, during the peak land 

disturbance, and after the project was completed and released by the regulatory agency. Benthic 

and fish communities, in addition to several water chemistry variables and leaf litter 

decomposition rates, were sampled. The researchers found a number of results: 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

— Virtually all at-site samples showed some degradation relative to upstream controls. 

— Impacts at sites downstream from construction sites were highly variable. 

— Degree of degradation was significantly affected by enforcement activities; stronger 

enforcement resulted in less environmental impact on the streams. 

— The stringency of the erosion and sediment control regulations proved unimportant 

compared to enforcement. 

They concluded that staffing, workload, attitudes, and enforcement activities strongly influenced 

downstream conditions. 

8.3.2 Erosion Control Practices 

Erosion controls are used to reduce the amount of sediment removed during construction and to 

prevent sediment from entering runoff. Erosion control is based on two main concepts: 

(1) disturb the smallest area of land possible for the shortest period of time, and (2) stabilize 

disturbed soils to prevent erosion from occurring. Table 8.3 shows cost and effectiveness 

information for several erosion control practices. 

8.3.2.1 Schedule projects so clearing and grading are done during the time of minimum 

erosion potential 

Often a project can be scheduled when the erosion potential of the site is relatively low. In many 

parts of the country, there is a certain period of the year when erosion potential is relatively low 

and construction scheduling could be very effective. For example, in the Pacific region, if 

construction can be completed during the six-month dry season (May 1 to October 31), 

temporary erosion and sediment controls may not be needed. In addition, in other areas of the 

country, erosion potential in northern and high-elevation areas is very high during the spring 

thaw. During that time, snowmelt generates a constant runoff that can erode soil. In addition, 

construction vehicles can easily turn the soft, wet ground into mud, which is more easily washed 

off the site. Therefore, in the north, limitations should be placed on clearing and grading during 

the spring thaw (Goldman et al., 1986). 

8.3.2.2 Phase construction 

Construction site phasing involves disturbing only small portions of a site at a time to prevent 

erosion in areas where no activity is occurring (CWP, 1997c). Grading and construction are 

completed and soils are effectively stabilized on one part of the site before they commence at 

another. This is different from the more traditional practice of construction site sequencing, in 

which construction occurs at only one part of the site at a time but site grading and other sitedisturbing activities typically occur all at once, leaving portions of the disturbed site vulnerable 

to erosion. Construction site phasing must be incorporated into the overall site plan early on. 

Elements to consider when phasing construction activities include (CWP, 1997c): 

8-12 
Management Measure 8: Construction Site Erosion, Sediment, and Chemical Control 

— Managing runoff separately in each phase; 

— Determining whether water and sewer connections and extensions can be included in the 

disturbed area and installed during the initial phases of disturbance; and 

— Providing separate construction and residential accesses to prevent conflicts between 

residents living in completed stages of the site and construction equipment working on 

later stages. 

Table 8.3: Cost and effectiveness of selected erosion control practices. 

a

Costs adjusted for inflation using the Consumer Pricing Index (BLS, 2001). 

Practice Percent TSS Removal 

Effectiveness 

References 

Cost 

(2001 Dollarsa

) 

Cost 

References 

Earth 

dike 

NA NA Small dikes: $2.50–

$6.50/linear ft 

Large dikes: $2.50/yd3

NAHB, 1995; 

SWRPC, 1991 

Pipe 

slope 

drain 

NA NA $5/linear ft for flexible 

PVC pipe; inlet and outlet 

structures additional 

NAHB, 1995 

Terraces 1%–12% slope: 70% less erosion 

12%–18% slope: 60% less erosion 

18%–24% slope: 55% less erosion 

USEPA, 1993 Average: $6/linear ft 

Range: $1.20–

$14.50/linear ft 

USEPA, 1993 

Check 

dams 

NA NA $100/dam (constructed of 

rock) 

NAHB, 1995 

Seeding Average: 90% 

Range: 50%–100% 

USEPA, 1993 Average: $0.10/yd2

Range: $0.05–$0.25/yd2

Maintenance costs: 15%–

25% of installation costs 

USEPA, 1993 

Mulching 53%–99.8% reduction of soil loss 

24%–78% reduction in water 

velocity 

Harding, 

1990 

Average: $0.38/yd2

Range: $0.21–$0.87/yd2

 USEPA, 1993 

Sodding 98–99% USEPA, 1993 Average: $2.20/yd2

Range: $1.10–$12/yd2

Maintenance costs: 5% of 

installation costs 

USEPA, 1993 

Erosion 

control 

blankets 

70% wheat straw/30% coconut 

fiber: 98.7% 

Straw: 89.2%–98.6% 

Curled wood fiber: 28.8%–93.6% 

Jute mats: 60.6% 

Synthetic fiber: 71.2% 

Nylon monofilament: 53.0% 

CWP, 1997a Biodegradable materials: 

 $0.50–$0.57/yd2

Permanent materials: 

 $3.00–$4.50/yd2

Staples: 

 $0.04–$0.05/staple 

Erosion Control 

Systems, Inc., 

personal 

communication, 

March 14, 2001 

Chemical 

stabilization 

PAM: 77–93% RosaEspinosa et 

al., No date 

PAM: $1.30–$38.50/lb Entry and 

Sojka, 1999; 

Sojka and 

Lentz, 1996 

A comparison of sediment loss from a typical development and from a comparable phased 

project showed a 42 percent reduction in sediment export in the phased project (CWP, 1997c). 

8-13 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Phasing can also provide protection from complete enforcement and shutdown of the entire 

project. If a contractor is in noncompliance in one phase or zone of a site only, that will be the 

area affected by enforcement activities. This approach can help to minimize liability exposure 

and protect the contractor financially (Deering, 2000b). 

8.3.2.3 Practice site fingerprinting 

Areas of a construction site are often unnecessarily cleared. Site fingerprinting involves clearing 

only those areas essential for conducting construction activities, leaving other areas undisturbed. 

The proposed limits of land disturbance should be physically marked off to ensure that only the 

land area required for buildings, roads, and other infrastructure is cleared. Existing vegetation, 

especially vegetation on steep slopes, should be avoided and preserved through fencing, signage, 

and site plan notations. 

8.3.2.4 Locate potential pollutant sources away from steep slopes, water bodies, and 

critical areas 

Material stockpiles, borrow areas, access roads, and other land-disturbing activities should be 

located away from critical areas such as steep slopes, highly erodible soils, and areas that drain 

directly into sensitive water bodies to reduce the potential for pollutant loadings. 

8.3.2.5 Route construction traffic to avoid existing or newly planted vegetation 

Where possible, construction traffic should be directed over areas that must be disturbed for 

other construction activity. This practice reduces the net total area that is cleared and susceptible 

to erosion. It also may help to decrease the area of compacted soils. 

8.3.2.6 Protect natural vegetation with fencing, tree armoring, and retaining walls or tree 

wells 

Tree armoring protects tree trunks from being damaged by construction equipment. Fencing can 

also protect tree trunks, but it should be placed at the tree's drip line or critical root zone. A tree's 

drip line is the minimum area around the tree in which the tree's root system should be 

undisturbed by cut, fill, or soil compaction caused by heavy equipment. When cutting or filling 

must be done near a tree, a retaining wall or tree well should be used to minimize the cutting of 

the tree's roots, the quantity of fill placed over the tree's roots, or soil compaction. 

8.3.2.7 Protect environmentally sensitive areas 

When construction is taking place in an aquifer recharge area, wetland, floodplain, or other 

sensitive area, special consideration should be given to minimizing the environmental impacts of 

construction activities. Disturbance to these areas should be limited and measures taken to reduce 

impacts if work is conducted near or in these features. For example, the North Carolina 

Department of Transportation (NCDOT) used an innovative technique to reduce the impact of 

cleanup activities on sensitive wetlands surrounding the newly constructed Croatan Sound 

Bridge. NCDOT used industrial vacuums traditionally used by the shipbuilding and roofing 

industries to move materials off-site rather than running potentially damaging vehicles over the 

8-14 
Management Measure 8: Construction Site Erosion, Sediment, and Chemical Control 

wetlands. Even with the purchase cost of the new equipment, NCDOT estimates a savings of 

more than $3 million. 

8.3.2.8 Stockpile topsoil and reapply as a soil amendment to reestablish vegetation 

Topsoil is essential to establish new vegetation, and it should be stockpiled and then reapplied to 

the site for revegetation. Reestablishment of vegetation is one of the most common and least 

expensive means to stabilize disturbed soils. 

− Reduced infiltration capacity, resulting in increased runoff, erosion, scouring, and sediment 

and other pollutant loads to receiving waters. 

− Decreased ground water recharge rates. 

− Reduced availability of subsurface water to plants, requiring homeowners to water more 

frequently. 

Soil amendments minimize development impacts on native soils by restoring infiltration capacity and 

the chemical characteristics of healthy soils. Amended soils provide greater infiltration and subsurface 

storage, which helps to maintain predevelopment conditions. Soil amendments provide the following 

water quality benefits (Low Impact Development Center, 2003): 

− Increased infiltration capacity of soil. 

− Filtering and breakdown of potential pollutants. 

− Decomposition of potential pollutants by soil microbes. 

− Reduced need for fertilizers, pesticides, and irrigation due to increased nutrients and 

moisture-holding capacity in soil. 

− Increasing soil stability, reducing erosion potential. 

− Added protection to ground water resources, especially from heavy metal contamination. 

Soil can be amended using compost, mulch, topsoil, lime and gypsum. A thorough analysis of the 

native soil should be conducted to maximize the benefits of soil amendments. 

Soil should be amended at the completion of construction to avoid compaction from heavy equipment. 

Care should be taken to ensure that amendments are implemented during the right season and under 

the right conditions in relation to other landscaping activities. 

The Importance of Soil Amendments

Soil with adequate soil structure, pore space, organic content, and biological activity not only promotes 

the establishment of new vegetation, but it also provides water quality benefits. When soils are 

compacted during construction activities and organic matter is not replaced, the following 

consequences may occur (Low Impact Development Center, 2003): 

8-15 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

8.3.2.9 Cover or stabilize soil stockpiles 

Unprotected stockpiles are very prone to erosion and therefore must be protected. Small 

stockpiles can be covered with a tarp to prevent erosion. Large stockpiles should be stabilized by 

erosion blankets, seeding, and/or mulching. 

8.3.2.10 Use wind erosion controls 

Wind erosion controls limit the movement of dust from disturbed soil surfaces and encompass 

many different practices. Wind barriers block air currents and are effective in controlling soil 

movement due to wind. Many different materials can be used as wind barriers, including solid 

board fences, snow fences, and bales of hay. Sprinkling moistens the soil surface with water and 

must be repeated as needed to be effective for preventing wind erosion (Delaware DNREC, 

1989); however, applications must be monitored to prevent excessive runoff and erosion. 

8.3.2.11 Intercept runoff above disturbed slopes and convey it to a permanent channel or 

storm drain 

Earth dikes, perimeter dikes/swales, or diversions can be used to intercept and convey runoff 

from above disturbed areas to undisturbed areas or drainage systems. An earth dike is a 

temporary berm or ridge of compacted soil that channels water to a desired location. A perimeter 

dike/swale or diversion is a swale with a supporting ridge on the lower side that is constructed 

from the soil excavated from the adjoining swale (Delaware DNREC, 1989). These practices 

should be used to intercept flow from denuded areas or newly seeded areas and to keep clean 

runoff away from disturbed areas. The structures should be stabilized within 14 days of 

installation. A pipe slope drain, also known as a pipe drop structure, is a temporary pipe placed 

from the top to the bottom of a slope to convey concentrated runoff down the slope without 

causing erosion (Delaware DNREC, 1989). 

8.3.2.12 On long or steep, disturbed, or man-made slopes, construct benches, terraces, or 

ditches at regular intervals to intercept runoff 

Benches, terraces, or ditches break up a slope by providing areas of low slope in the reverse 

direction. These structures keep water from proceeding down the slope at increased volume and 

velocity. Instead, the flow is directed to a suitable outlet or protected drainage system. The 

frequency of benches, terraces, or ditches will depend on the erodibility of the soils, steepness 

and length of the slope, and rock outcrops. This practice should be used if there is a potential for 

erosion along the slope. 

8.3.2.13 Use retaining walls 

Retaining walls can be used to decrease the steepness of a slope. If the steepness of a slope can 

be reduced, the runoff velocity and erosion potential can be decreased. 

8.3.2.14 Provide linings for urban runoff conveyance channels 

Construction activities often increase the velocity and volume of runoff. Increases in runoff 

velocity and volume often cause erosion in newly constructed or existing urban runoff 

8-16 
Management Measure 8: Construction Site Erosion, Sediment, and Chemical Control 

conveyance channels. If the runoff during or after construction will cause erosion in a channel, 

the channel should be lined or flow control practices should be installed. The first choice of 

lining is grass or sod because they reduce runoff velocities and provide water quality benefits 

through filtration and infiltration. If the velocity in the channel would erode the grass or sod, turf 

reinforcement mats, riprap, concrete, or gabions can be used. 

8.3.2.15 Use check dams 

Check dams are small, temporary dams constructed across a swale or channel. They can be 

constructed using gravel, rock, gabions, or straw bales. They are used to reduce the velocity of 

concentrated flow and, therefore, to reduce erosion in a swale or channel. Proper design and 

maintenance of check dams is crucial to their ability to function as an erosion control measure. 

Design considerations include dams to control runoff velocity; hydraulic capacity to store and 

release runoff in a non-erosive manner; stability of dam construction materials; foundation 

preparation; construction moisture; and density control. Maintenance requirements include the 

periodic removal of sediment collected above the dam; immediate repair of damage; and removal 

of temporary dams when they are no longer needed (Loser, 2003). 

8.3.2.16 Seed disturbed areas 

Seeding establishes a vegetative cover on disturbed areas and is very effective in controlling soil 

erosion once a dense vegetative cover has been established. Seeding establishes permanent 

erosion control in a relatively short amount of time and has been shown to decrease solids load 

by 99 percent (CWP, 1997a). The three most common seeding methods are: (1) broadcast 

seeding, in which seeds are scattered on the soil surface; (2) hydroseeding, in which seeds are 

sprayed on the surface of the soil with a slurry of water; and (3) drill seeding, in which a tractordrawn implement injects seeds into the soil surface. Broadcast seeding is most appropriate for 

small areas and for augmenting sparse and patchy grass covers. Hydroseeding is often used for 

large areas (in excess of 5,000 square feet) and is typically combined with tackifiers, fertilizers, 

and fiber mulch. Drill seeding is expensive and is cost-effective only on sites greater than 2 

acres. Bare soils should be seeded or otherwise stabilized within 15 calendar days after final 

grading. Denuded areas that are inactive and will be exposed to rain for 15 days or more should 

also be temporarily stabilized, usually by planting seeds and establishing vegetation during 

favorable seasons. In very flat, non-sensitive areas with favorable soils, stabilization may involve 

simply seeding and fertilizing. The Soil Quality Institute (SQI, 2000) recommends that soils 

compacted by grading should be broken up or tilled before vegetating. 

To establish a vegetative cover, it is important to use seeds from adapted plant species and 

varieties that have a high germination capacity. Supplying essential plant nutrients, testing the 

soil for toxic materials, and applying an adequate amount of lime and fertilizer can overcome 

many unfavorable soil conditions and establish adequate vegetative cover. Soils should be tested 

prior to application to determine the amount of lime or fertilizer needed. Specific information 

about seeds, various species, establishment techniques, and maintenance can be obtained from 

Erosion Control & Conservation Plantings on Noncropland (Landschoot, 1997) or a local 

Cooperative State Research, Education, and Extension Service (http://www.csrees.usda.gov/) or 

Natural Resources Conservation Service (http://www.nrcs.usda.gov) office. 

8-17 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

8.3.2.17 Use mulches 

Newly established vegetation does not have as extensive a root system as existing vegetation, 

and therefore it is more prone to erosion, especially on steep slopes. Additional stabilization 

should be considered during the early stages of seeding. This extra stabilization can be 

accomplished using mulches or mulch mats, which can protect the disturbed area while 

vegetation becomes established. 

Mulching involves applying plant residues, compost material, or other suitable materials on 

disturbed soil surfaces. Mulch and mulch mat materials include tacked straw, wood chips, jute 

netting, coir/coconut fiber, and compost mix, and are sometimes covered by blankets or netting. 

Mulching alone should be used only for temporary protection of the soil surface or when 

permanent seeding is not feasible. The useful life of mulch varies with the material used and the 

amount of precipitation, but is approximately two to six months. Mulching and/or sodding may 

be necessary as slopes become moderate to steep, as soils become more erodible, and as areas 

become more sensitive. 

During the times of the year when vegetation cannot be established, mulch should be applied to 

moderate slopes and soils that are not highly erodible. On steep slopes or highly erodible soils, 

multiple mulching treatments should be used. 

The Texas Transportation Institute (2004) undertook a study to measure the performance of the 

use of compost and shredded wood mulches on highway rights-of-way. The institute found that 

compost applied to sand produced 92 percent vegetation cover, compost on clay produced 99 

percent vegetation cover, and wood chips treated with a tackifier on clay produced 95 percent 

vegetation cover. Other treatments, including wood chips/tackifier on sand and wood chips with 

tackifier and germination stimulant on sand and clay did not produce adequate vegetation cover 

for erosion control (only 48 to 57 percent cover). They concluded that mulch could be 

advantageous as an erosion control method because it did not need to be removed after 

construction and it acted as a soil amendment to encourage vegetation establishment. 

Additionally, use of natural mulches such as compost and wood chips promotes recycling of 

waste materials and reduces the amount of wastes disposed of in landfills. 

Hydromulches containing biosolids or other fertilizers are often useful on soils with poor nutrient 

organic content and in situations where there are steep slopes or other erosive forces that affect 

revegetation (e.g., wind). 

8.3.2.18 Use sodding for permanent stabilization 

Sodding permanently stabilizes an area with a thick vegetative cover. Sodding provides 

immediate stabilization and should be used in critical areas or where establishing permanent 

vegetation by seeding and mulching would be difficult. Sodding is also a preferred option when 

there is high erosion potential during the period of vegetative establishment from seeding. 

According to the Soil Quality Institute (SQI, 2000), soils that have been compacted by grading 

should be broken up or tilled before placing sod. 

8-18 
Management Measure 8: Construction Site Erosion, Sediment, and Chemical Control 

8.3.2.19 Install erosion control blankets 

Turf reinforcement mats (TRMs) combine vegetative growth and synthetic materials to form a 

high-strength mat that helps prevent soil erosion in drainage areas and on steep slopes (USEPA, 

1999). TRMs enhance the natural ability of vegetation to permanently protect soil from erosion. 

They are composed of interwoven layers of non-degradable geosynthetic materials, such as 

polypropylene, nylon, and polyvinyl chloride netting, stitched together to form a threedimensional matrix. They are thick and porous enough to allow filling and retention of soil. 

In addition to providing scour protection, the mesh netting of TRMs is designed to enhance 

vegetative root and stem development. By protecting the soil from scouring forces and enhancing 

vegetative growth, TRMs can raise the threshold of natural vegetation to withstand higher 

hydraulic forces on stabilization slopes, streambanks, and channels. In addition to reducing flow 

velocities, the use of natural vegetation provides removal of particulates through sedimentation 

and soil infiltration and improves the aesthetics of a site. 

In general, TRMs should not be used: 

— To prevent deep-seated slope failure due to causes other than surficial erosion; 

— When anticipated hydraulic conditions are beyond the limits of TRMs and natural 

vegetation; 

— Directly beneath drop outlets to dissipate impact force (although they can be used beyond 

the impact zone); or 

— Where wave height might exceed 1 foot (although they may be used to protect areas upslope of the wave impact zone). 

The performance of a TRM-lined conveyance system depends on the duration of the runoff event 

to which it is subjected. For short-term events, TRMs are typically effective at flow velocities of 

up to 15 ft/sec and shear stresses of up to 8 lb/ft2

 (USEPA, 1999), however, specific highperformance TRMs may be effective under more severe hydraulic conditions. Practitioners 

should check with manufacturers for the specifications and performance limits of different 

products. 

In general, the installed cost of TRMs ranges from $5/yd2

 to $15/yd2 (USEPA, 1999). Factors 

influencing the cost of TRMs include: (1) the type of TRM material required; (2) site conditions, 

such as the underlying soils, the steepness of the slope, and other grading requirements; and 

(3) installation-specific factors such as local construction costs. 

In most cases, TRMs cost considerably less than concrete and riprap solutions. For example, a 

project in Aspen, Colorado, used more than 23,000 yd2 of TRMs to line channels for a horse 

ranch development project (Theisen, 1996). The TRMs were installed at a cost of $8.25/yd2

. This 

cost was substantially less than the $20/yd2

 estimate for the rock riprap alternative. 

8-19 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

8.3.2.20 Use chemicals such as PAM to stabilize soils 

Polymers can be used to reduce erosion and also to control sediment contained in runoff. 

Polyacrylamide (PAM) is a polymer produced mainly for agricultural use to control erosion and 

promote infiltration on irrigated lands (Sojka and Lentz, 1996). It is also being tested for use at 

construction sites to reduce erosion from disturbed areas (Aicardo, 1996; Roa-Espinosa et al., no 

date). When applied to soils, PAM binds to soil particles and forms a gel that decreases soil bulk 

density, absorbs water, and binds fine-grained soil particles. 

PAM is available in powder form or as aqueous concentrate, in blocks and cubes, and as an 

emulsified concentrate; each type has benefits and drawbacks that alter its applicability in 

different settings and by different application methods. PAM costs $1.30 to $38.50 per pound 

(Entry and Sojka, 1999; Sojka and Lentz, 1996) and has been shown to achieve a 77 to 93 

percent reduction in sediment loss from disturbed sites (Roa-Espinosa et al., no date). 

Application of PAM improves surface water quality by decreasing suspended solids and the 

phosphorus, nitrogen, pesticides, pathogens, salts, metals, and BOD usually associated with 

sediment loading. However, PAM may detrimentally affect ground water quality by increasing 

leaching of nutrients, pesticides, and pathogens as a result of improved infiltration. Although 

careful application of PAM at prescribed rates can partially mitigate its negative effects on 

ground-water quality, its effects on water quality and wildlife are still unknown. 

Questions have arisen as to PAM's environmental toxicity. Anionic PAM, the form found most 

often in erosion control products, has not been proven to be toxic to aquatic, soil, or plant 

species. The molecule is too large to cross membranes, so it is not absorbed by the 

gastrointestinal tract, is not metabolized, and does not bioaccumulate in living tissue. Cationic 

PAM, although not of major concern for erosion control applications, has been shown to be toxic 

to fish because of its affinity to anionic hemoglobin in the gills. 

Most of the concern for PAM toxicity has arisen because of acrylamide (AMD), the monomer 

associated with PAM and a contaminant of the PAM manufacturing process. In laboratory 

experiments, AMD has been shown to be both a neurotoxin and a carcinogen. Current 

regulations require that AMD not exceed 0.05 percent in PAM products. Although there seems to 

be little risk from AMD as a result of prescribed application of PAM, it is uncertain what effects 

might result from spills, over-application, or other accidents. 

Flocculation and filtration of colloidal solids in construction site runoff

Runoff discharged from an unstabilized sediment basin at a commercial construction site was not 

meeting water quality standards due to high suspended solids content, despite a filtering device 

installed at the basin’s outflow. The filter was designed to filter larger particles and gross solids, but 

did not treat silt-sized and colloidal particles. To address the smaller particle sizes, the contractor 

installed a sump consisting of 2 parts: a pit into which a 1,000-foot pipe discharged runoff for settling 

and a grid of jute baffles that would filter finer floc. A polyacrylamide blend was used to stabilize the pit 

and baffle grid. Solid blocks of flocculant were placed in the upstream end of the discharge pipe to 

introduce the material gradually into the runoff stream. Mixing occurred in the pipe, settling of floc 

occurred in the quiescent pit, and the baffles filtered remaining solids and floc. Samples taken at 

inflow and outflow points show dramatic clarification of runoff (Price and Company, Inc., 2004). 

8-20 
Management Measure 8: Construction Site Erosion, Sediment, and Chemical Control 

Polymers for Sediment Control 

Polymers also can be used to control sediments that have 

been mobilized and entrained in runoff. Minton and 

Benedict (1999) examined the use of polymers to clarify 

construction site runoff that had been detained on-site. 

The researchers used a multi-phase system to remove 

sediments and associated pollutants from construction site 

runoff. The first phase involved collection of storm water at 

interception points using the permanent drainage system 

installed early in the construction period and/or building 

excavations (see Figure 8.1). The collected runoff was 

then diverted, usually by pumping, to one or more storage 

ponds. (The permanent postdevelopment detention and 

treatment system, as required by local regulations, could 

be used for this storage during the construction phase 

given that it has sufficient capacity to handle site runoff, 

with supplemental storage provided as necessary.) The 

water was then pH-adjusted to optimize flocculation based 

on the particular polymer used. Finally, the water was 

pumped to one of two treatment cells, during which time 

the polymer was added (upstream of the transfer pump to 

maximize mixing and flocculation). 

Two treatment cells were used so that settling could take 

place in one cell while runoff was pumped into the second 

cell. The floc was allowed to settle for a few hours to 

several days, with the most common practice being an 

overnight settling period. Water was discharged to the 

public discharge system using a float device with a 4-inch 

discharge system and a 12-inch clearance to keep the 

float from picking up settled sediment. Alternatively, the clarified water could be discharged to the sanitary 

sewer if problems arose in the treatment system. 

Table 8.4 presents performance data for the six sites studied. Median turbidities of the untreated storm 

water varied between sites. These differences might have been caused by differences in the percentage 

of soil fines, the slopes, and the application of standard management practices. Developers at the test 

sites reported costs to be between 0.8 and 1.5 percent of the total construction cost, while another 

developer reported an approximate cost of $1/ft2

 for the treatment system. Temporary storage and 

treatment ponds, as well as piping, pumps, and other equipment, accounted for the majority of the costs 

associated with polymer treatment. 

Table 8.4: Summary of operating performance data for six test sites (Minton and Benedict, 1999)a

. 

Polymer Dosage Influent Turbidity Effluent Turbidity pH Control 

Site Range Median Range Median Range Median Frequencyb

 Typec

1 25–250 75 12–2,960 200 1–45 6 45% acid 

2 10–200 100 31–4,700 2,000 1.9–39 11 16% both 

3 50–>100 100 12.9–900 150 0.5–45 7 18% soda ash 

4 50–200 100 8–4,000 400 <1–32.5 6 0% – 

5 300–400 350 2,780–

17,000 14,000 0.8–23 8 97% soda ash 

6 85–140 110 17–6,650 117 1.7–18 4 85% both a Excludes the start-up period when effluent turbidities were not yet at desired levels (usually a week or two for most 

sites). b Approximate percentage of the number of operating days on which pH adjustment occurred. c Most frequent 

form of pH adjustment: soda ash or sulfuric acid. 

Figure 8.1: Schematic of the basic 

polymer treatment system (Minton 

and Benedict, 1999). 

Permanent

Drainage

System

Storage Pond

Treatment

Cell

Operations

Shed

Treatment

Cell

Polymer Added

To public drainage system

or directly to receiving water

8-21 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

8.3.2.21 Use wildflower cover 

Because of the hardy drought-resistant nature of wildflowers, in some cases they may be more 

beneficial as an erosion control practice than turf grass. Though not as dense as turf grass, 

wildflower thatches and associated grasses are expected to be as effective in erosion control and 

contaminant absorption. An additional benefit of wildflower thatches is providing habitat for 

wildlife, including insects and small mammals. Because thatches of wildflowers do not need 

fertilizers, pesticides, or herbicides, and watering is minimal, implementation of this practice 

may result in cost savings. A wildflower thatch requires several years to become established, but 

maintenance requirements are minimal once established. Native seeds should be used because 

they will be better adapted to local conditions. If possible, the seed source should be within 

250 miles of the proposed project for promotion of native species. 

8.3.3 Sediment Control Practices 

Sediment controls capture sediment that is transported in runoff. Filtration and gravitational 

settling during detention are the main processes used to remove sediment from urban runoff. 

Table 8.5 shows cost and effectiveness information for several sediment control practices. 

8.3.3.1 Install sediment basins 

Sediment basins, also known as silt basins, are engineered impoundment structures that allow 

sediment to settle out of the urban runoff. They are installed prior to full-scale grading and 

remain in place until the disturbed portions of the drainage area are fully stabilized. They are 

generally located at the low point of sites, away from construction traffic, where they can be used 

to trap sediment-laden runoff. Basin dewatering is achieved either through a single riser and 

drainage hole leading to a suitable outlet on the downstream side of the embankment or through 

the gravel of the rock dam. In both cases, water is released at a substantially slower rate than 

would be possible without the control structure. 

The following are general specifications for sediment basin design criteria as presented in 

Schueler (1997): 

— Provide 1,800 to 3,600 cubic feet of storage per contributing acre (a number of states, 

including Maryland, Pennsylvania, Georgia, and Delaware, recently increased the storage 

requirement to 3,600 ft3 or more [CWP, 1997b]). 

— Surface area equivalent to 1 percent of drainage area (optional, seldom required). 

— Riser with spillway capacity of 0.2 ft3

/s/ac of drainage area (peak discharge for 2-year 

storm with 1-foot freeboard). 

— Length-to-width ratio of 2 or greater. 

— Basin side slopes no steeper than 2:1 (horizontal to vertical). 

— Safety fencing, perforated riser, dewatering (optional, seldom required). 

8-22 
Management Measure 8: Construction Site Erosion, Sediment, and Chemical Control 

Table 8.5: Cost and effectiveness for selected sediment control practices. 

Practice 

Percent 

TSS Removal 

Effectiveness 

References 

Cost 

(2001 dollarsa) 

Cost 

References 

Sediment 

basin 

Average: 70% 

Range: 42%-100% 

CWP, 1997d; 

Millen et al., No 

date; USEPA, 1993 

For 50,000 ft3 of storage space: 

 Average: $0.80/ft3

 Range: $0.25–$1.70/ft3

 storage 

For more than 50,000 ft3

 of 

storage space: 

 Average: $0.40/ft3

 Range: $0.13–$0.52/ft3

 storage 

USEPA, 1993 

Modified 

risers and 

skimmers 

Single orifice: 83% 

Perforated risers: 

68%–94% 

Perforated risers 

w/filter fabric: 79% 

Skimmer: 83%–97% 

Jarrett, 1999, 

Schueler, 1997 

NA NA 

Sediment 

trap 

50%–70% Stahre and 

Urbonas, 1990 

Average: $0.80/ft3 storage 

Range: $0.25–$2.65/ft3

 storage 

Maintenance costs: 20% of 

installation costs 

Brown and 

Schueler, 

1997; 

USEPA, 1993 

Silt fence 40%–100% Barrett et al., 1995; 

Wishowski et al., 

1998; CWP, 1997e 

$3.80–$9.90/linear ft SWRPC, 

1991; 

USEPA, 1992 

Inlet 

protection 

NA NA $65–$131/inlet USEPA, 1993 

Stabilized 

construction 

entrance 

NA NA Without wash rack: 

 Average: $2,620/entrance 

 Range: $1,310–$5,240/entrance 

With wash rack: 

 Average: $3,930/entrance 

 Range: $1,310–$6,550/entrance 

USEPA, 1993 

Vegetated 

filter strips 

75-ft width: 54% 

15-ft width: 84% 

Yu et al., 1993 Established from existing 

vegetation: $0 

Established from seed: 

 Average: $530/acre 

 Range: $270–$1,310/acre 

Established from sod: 

 Average: $14,190/acre 

 Range: $6,000–$63,300/acre 

Note: Values do not include land 

costs or costs associated with 

installing a level spreader 

USEPA, 1993 

a

Costs adjusted for inflation using the Bureau of Labor Statistics Inflation Calculator. NA: Not available

Sediment basins can be classified as either temporary or permanent structures, depending on the 

length of their service. If they are designed to function for less than 36 months, they are 

classified as temporary; otherwise, they are considered permanent. Temporary sediment basins 

can also be converted into permanent urban runoff management ponds. Conversion minimizes 

additional disturbance and can be used where it will be difficult to restore an area previously 

used as a temporary sediment basin. When sediment basins are designed as permanent structures, 

they must meet all standards for wet ponds. It is important to note that even the best-designed 

sediment basin seldom exceeds 60 to 75 percent TSS removal. This number should be taken into 

consideration when selecting a sediment control practice. As described above, trapping 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

efficiency in sediment basins can be improved through the use of advanced sediment-settling 

controls. 

8.3.3.2 Use modified risers and skimmers 

Because traditional riser designs provide little treatment to remove sediments, efforts have been 

made to improve the design of sediment basins to facilitate greater pollutant removal. 

Modifications to traditional designs that improve sediment removal efficiency include using 

perforated risers or perforated risers wrapped in a gravel jacket or filter fabric. An alternative to 

the riser is a skimmer device that floats on the surface of water in the basin (Faircloth, 1999). 

The skimmer is made of a straight section of PVC pipe equipped with a float and attached with a 

flexible coupling to a flow-controlled outlet at the base of the riser. Because the skimmer floats, 

it rises and falls with the level of water in the basin and drains only the cleanest top layer of 

runoff. Since the skimmer falls to the bottom of the basin as the basin drains, it is capable of 

more thorough dewatering than a traditional riser, thereby restoring the maximum runoff storage 

capacity. The sediment-removal performance of basins equipped with skimmer dewatering 

devices has been shown to be nearly 97 percent for a simulated 2-year, 24-hour storm (Schueler, 

1997). 

Jarrett (1999) tested the sediment-removal effectiveness of several types of basins (outlet 

placement, deeper/shallower, barrier/no barrier) and outlet designs, including perforated risers 

(with and without filter fabric), single-orifice risers, and several sizes of skimmers. Table 8.6 

shows the sediment retention efficiency results of Jarrett's different treatments. 

Jarrett drew the following conclusions from his study: 

— Perforated risers and single-orifice risers had similar sediment losses. 

— Deeper permanent pools resulted in greater sediment removal. 

— Sediment loss was attributed partly to resuspension and partly to basin erosion. 

— Perforated risers resulted in 1.8 times greater sediment loss than skimmers when the 

outlet devices were placed in the principal spillway. 

— Barriers that trisect basin volume reduced sediment loss when perforated risers were used 

but did not reduce sediment loss when skimmers were used. 

— Silt-sized particles were most likely to be lost from sediment basins. 

— Longer dewatering time resulted in less overall sediment loss. 

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Management Measure 8: Construction Site Erosion, Sediment, and Chemical Control 

 Table 8.6: Sediment retention efficiencya of sediment basins (Jarrett, 1999). 

Treatmentb

Outlet Control Basin Size (m3) 

Hydrograph Volume Injected (m3) 

Emergency Spillway Used Barrier Used Dewatering Time (hr) Permanent Pool Depth (m) Sediment Loss (kg) Sediment Retention Efficiency (%) 

1 Perforated riser 140 100 No No 24 0.15 32 79 

2 Single orifice 140 100 No No 24 0.15 26 83 

5 Perforated Riser 140 100 No No 24 0.46 1 92 

6 Perforated riser 

with filter fabric 140 100 No No ? 0.15 32 79 

7 Skimmer 140 100 No No 24 0.15 17 89 

8 Perforated riser 140 100 No Yes 24 0.15 24 84 

9 Skimmer 140 100 No No 24 0.15 20 87 

10 Perforated riser 140 100 No No 6 0.15 49 68 

10 Perforated riser 140 100 No No 168 0.15 9 94 

10 Skimmer 140 100 No No 6 0.15 22 86 

10 Skimmer 140 100 No No 168 0.15 5 97 

11 Perforated riser 140 100 Yes No 24 0.15 44 71 

11 Skimmer 140 100 Yes No 24 0.15 26 83 

11a Perforated riser 50 50 No No 24 0.15 22 86 

11a Skimmer 50 50 No No 24 0.15 7 95 

3,4 Resuspension equaled 24% of sediment lost from basin 

3,4 Erosion from basin sides and bottom equaled 24% of sediment lost from basin 

1 Basin suspension was completely mixed during hydrograph inflow 

1 Basin suspension quickly stratified when inflow energy was reduced to zero a

The 90 percent and greater TSS removal rates might be difficult to achieve in the field because (1) sizing criteria are much 

higher in Pennsylvania; (2) these were laboratory, not field, tests; and (3) maintenance was above average. 

b

In all treatments, effective soil injected was 154 kg.

8.3.3.3 Install sediment traps 

Sediment traps are small impoundments that allow sediment to settle out of runoff water. They 

are typically installed in a drainageway or other point of discharge from a disturbed area. 

Temporary diversions can be used to direct runoff to the sediment trap. Sediment traps are ideal 

for sites 1 acre and smaller and should not be used for areas greater than 5 acres. They typically 

have a useful life of approximately 18 to 24 months. A sediment trap should be designed to 

maximize surface area for infiltration and sediment settling. This design increases the 

effectiveness of the trap and decreases the likeliness of backup during and after periods of high 

runoff intensity. The approximate storage capacity of each trap should be at least 1800 ft3/acre of 

disturbed area draining into the trap (Smolen et al., 1988). (A number of states, including 

Maryland, Pennsylvania, Georgia, and Delaware, recently increased the storage requirement to 

3,600 ft3

 or more [CWP, 1997b].) 

8.3.3.4 Use silt fence 

Silt fence, also known as filter fabric fence, is available in several mesh sizes from many 

manufacturers. Sediment is filtered out as runoff flows through the fabric. Such fences should be 

used only where there is sheet flow (no concentrated flow), and the maximum drainage area to 

the fence should be 0.5 acre or less per 100 feet of fence. To ensure sheet flow, a gravel collar or 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

level spreader can be used upslope of the fence. Many types of fabrics are available 

commercially. The characteristics that determine a fence’s effectiveness include filtration 

efficiency, permeability, tensile strength, tear strength, ultraviolet resistance, pH effects, and 

creep resistance. 

The longevity of silt fences depends heavily on proper installation and maintenance. CWP 

(1997d) identified several conditions that limit the effectiveness of silt fences: 

— The length of the slope exceeds 50 feet for slopes of 5 to 10 percent, 25 feet for slopes of 

10 to 20 percent, or 15 feet for slopes greater than 20 percent. 

— The silt fence is not aligned parallel to the slope contours. 

— The edges of the silt fence are not curved uphill, allowing flow to bypass the fence. 

— The length of disturbed area draining to the fence is greater than 100 feet. 

— The fence receives concentrated flow without reinforcement. 

— The fence was installed below an outlet pipe or weir. 

— The silt fence is upslope of the exposed area. 

— The silt fence alignment does not consider construction traffic. 

— Sediment deposits behind the silt fence reduce capacity and increase breach potential. 

— The alignment of the silt fence mirrors the property line or limits of disturbance but does 

not reflect ESC needs. 

EvTEC found that the slicer performed as well as or better than the best trenching method and was 

superior to less stringent methods of trenching. Slicing took less time (1.75 to 4 times faster) and was 

therefore cost-effective because of man-hour savings. The slicing method prevented runoff seepage 

and blowout better than most trenching methods and performed as well as the best trenching method. 

Overall, the static slicing method offers several advantages over traditional trenching methods, 

including maneuverability, minimal soil-handling and manual labor, consistent depth and compaction, 

and ease of installation in windy conditions, on steep side slopes, through rocky soils, and in saturated 

conditions. 

EvTEC tests a static slicing silt fence installer

A static slicing silt fence installer was recently tested by EPA's Environmental Technology Evaluation 

Center (EvTEC, 2001). The goal of the testing was to determine if slicing was as better method than 

trenching with respect to performance, cost, and ease of use. The static slicing method, an alternative 

to traditional trenching methods, involves inserting a narrow custom-shaped blade at least 10 inches 

into the ground and simultaneously pulling silt fence fabric into the opening created as the blade is 

pulled through the ground. The tip of the blade is designed to slightly disrupt soil upward, preventing 

horizontal compaction of the soil and simultaneously creating an optimum soil condition for future 

mechanical compaction. Compaction follows using a tire on the tractor that pulls the slicing machine. 

Post-setting and driving, followed with attaching the fabric to the post, finalizes the installation. 

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Management Measure 8: Construction Site Erosion, Sediment, and Chemical Control 

These conditions can be avoided with proper siting, installation, and maintenance. Silt fences 

typically have a useful life of approximately 6 to 12 months. 

8.3.3.5 Install compost filter berms 

Compost berms can be installed by spraying compost mixture along the perimeter of a denuded 

area to form a mound. The berms are designed to filter runoff by absorbing flows into the 

compost mixture’s void space and gradually releasing them into the ground or offsite. They are 

usually installed at the bottom of a slope, but they also can be installed at the top of the denuded 

area to prevent clean runoff from entering exposed areas. Berms are typically installed in lieu of 

silt fence and are sized at 1 foot high and 2 feet wide (Tyler, 2001). 

Compost berms can be used in conjunction with compost blankets (a sprayed layer of compost 

mix that functions as a mulch, see section 8.3.2.17); a berm at the top of the slope protects the 

compost blankets from erosion by preventing water from flowing underneath the protective 

layer, and a berm at the bottom of the slope provides filtration (Tyler, 2001). 

Caine (2001) installed a triangular cross-section compost berm that was 16 to 18 inches high and 

36 inches wide at its base. Installation cost was approximately $3.68 per linear foot. Runoff 

detention time was 17 to 26 minutes. Water was distributed throughout the berm and was 

released at multiple points. The berm filtered the runoff such that turbidity was reduced by 67 

percent. Caine noted that the runoff mobilized humic and tannic acids from the organic material, 

causing the water passing through the berm to become discolored. One benefit of compost berms 

is that they do not require removal after construction is completed; they can be spread over the 

ground surface as topsoil or a soil amendment. 

Mesh socks filled with composted material can be used in lieu of filter berms where the use of 

loose material is not practical, such as where flows might be concentrated near stream banks or 

shorelines (Goldstein, 2002). These filter socks function in the same manner as compost filter 

berms, but they are more contained. 

8.3.3.6 Establish inlet protection 

Inlet protection consists of a barrier placed around a storm drain inlet, which traps sediment 

before it enters the storm sewer system. There are five basic types of inlet protection structures: 

silt fence barriers, straw bale inlet barriers, block and gravel drop inlet filters, block and gravel 

curb inlet filters, and various excavated drop inlet protection measures (NAHB, 1995). The 

structures should be placed at the perimeter of the inlet structure. Inlet protection is appropriate 

for small drainage areas (1 acre or less) and can be used during rainy seasons (California 

Regional Water Quality Control Board, 1999). The structures can handle sheet flow with 

velocities less than 0.014 m3

/s; block and gravel barriers should be used in cases where 

concentrated flows exceed 0.014 m3/s. 

8.3.3.7 Designate and reinforce construction entrances 

A construction entrance is a pad of gravel or rock over filter cloth located where traffic enters 

and leaves a construction site. As construction vehicles drive over the gravel, mud and sediment 

are collected from the vehicles' wheels. To maximize the effectiveness of this practice, the rock 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

pad should be at least 50 feet long and 10 to 12 feet wide. The gravel should be 1- to 2-inch 

aggregate 6 inches deep laid over a layer of filter fabric. Maintenance might include pressurewashing the gravel to remove accumulated sediments and adding more rock to maintain adequate 

thickness. Runoff from this entrance should be treated before exiting the site. This practice can 

be combined with a designated truck wash-down station to ensure sediment is not transported 

off-site. 

8.3.3.8 Install vegetated filter strips 

Vegetated filter strips are low-gradient vegetated areas that are planted and used to filter 

overland sheet flow. Runoff must be evenly distributed across the filter strip. Channelized flows 

decrease the effectiveness of filter strips. Level spreading devices are often used to distribute the 

runoff evenly across the strip (Dillaha et al., 1989). 

Vegetated filter strips should have relatively low slopes and adequate length and should be 

planted with erosion-resistant plant species. The main factors that influence the removal 

efficiency are the vegetation type, soil infiltration rate, and flow depth and travel time. These 

factors are dependent on the contributing drainage area, slope of strip, degree and type of 

vegetative cover, and strip length. Maintenance requirements for vegetated filter strips include 

sediment removal and inspections to ensure that dense, vigorous vegetation is established and 

concentrated flows do not occur. 

8.3.3.9 Use vegetated buffers 

Like filter strips, vegetated buffers provide a physical separation between a construction site and 

a water body. The difference between a filter strip and a vegetated buffer area is that a filter strip 

is an engineered system (soils, plants, slope, width, depth), whereas a buffer is a naturally 

occurring filter system. Vegetated buffers remove nutrients and other pollutants from runoff, trap 

sediments, and shade the water body to optimize light and temperature conditions for aquatic 

plants and animals (Welsch, no date). Preservation of vegetation for a buffer should be planned 

before any site-disturbing activities begin to minimize the impact of construction activities on 

existing vegetation. Trees should be clearly marked at the drip-line to preserve them and to 

protect them from ground disturbances around the base of the tree. 

Proper maintenance of buffer vegetation is important. Maintenance requirements depend on the 

plant species chosen, soil types, and climatic conditions. Maintenance activities typically include 

fertilizing, liming, irrigating, pruning, controlling weeds and pests, and repairing protective 

markers (e.g., fluorescent fences and flags). 

8.3.4 Develop and Implement Programs to Control Chemicals and Other 

Construction Materials 

8.3.4.1 Develop and implement a materials management program 

Areas where materials are stored at a construction site can be sources of runoff contamination 

due to poor housekeeping and accidental spills. Improving storage and materials management 

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Management Measure 8: Construction Site Erosion, Sediment, and Chemical Control 

practices will help minimize exposure and risk. Erodible or potentially hazardous materials 

should be stored in such a manner as to prevent contact with rainfall or runoff. In general, 

materials should be stored in a secure, dry, covered area that is equipped with an impermeable 

floor and berms to prevent spills from reaching surrounding soils, ground water, and surface 

water. Conducting an inventory of all materials used on-site and assessing the potential they pose 

for contact with runoff will help in implementing effective controls. 

Properly store, handle, and apply pesticides. In general, pesticides should be used only when 

absolutely necessary. Instructions listed on the packaging should be followed when using, 

handling, or disposing of these chemicals. Consideration should be given to local regulations that 

may govern the use or disposal of pesticide chemicals or their containers. To reduce the risk of 

contaminating runoff, the following practices should be implemented: 

— Store pesticides in a secure, dry, covered area that has an impermeable floor. 

— Provide curbs or dikes around the storage area to prevent spills and leaks from reaching 

unprotected areas. 

— Provide site personnel with the proper pesticide spill response training and have adequate 

measures on-site to contain and clean up pesticide spills. 

— Strictly follow recommended application rates and application methods. 

— Handle pesticide wastes appropriately. Many pesticides are considered hazardous wastes 

when they are disposed of. Pesticide wastes should be managed as required by all 

applicable waste regulations. 

Properly store, handle, and apply petroleum products. The following practices can help to 

reduce the risk of runoff contamination from petroleum products: 

— Store petroleum products in designated areas that are covered, have impermeable floors, 

and are surrounded with dikes, berms, or absorbent pads to contain any spills. 

— Provide site personnel with the proper spill response training and have adequate measures 

on-site to contain and clean up petroleum spills. Store spill cleanup equipment in fuel 

storage areas or on board maintenance and fueling vehicles. 

— Conduct periodic preventive maintenance of on-site equipment and vehicles to prevent 

leaks. 

Properly store, handle, and apply fertilizers and detergents. A number of steps can be taken to 

reduce the risks of nutrient pollution: 

— Minimize the use of fertilizers and detergents. Determine the smallest amounts needed 

for the tasks at hand and avoid using unnecessary amounts. Apply fertilizers and use 

detergents only in the recommended manner and never in amounts greater than those 

recommended. 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

— When applying fertilizers to soil, apply them at a depth of 2 to 6 inches and not on the 

surface. This approach will limit the contact between runoff and nutrients. 

— Apply fertilizers more frequently but at lower application rates. 

— Implement appropriate erosion and sediment control practices that will control and limit 

the amount of nutrients leaving the site due to attachment to soil particles. 

— Conduct washing/cleaning operations in designated areas that are equipped to contain 

wash water and prevent it from being discharged to the site runoff collection and 

conveyance system. 

— Do not mix surplus products together unless following specific instructions from the 

manufacturer. 

Properly store, handle, and apply hazardous products. Most problems associated with the 

disposal of hazardous materials are the result of carelessness, not following recommended 

procedures, or not using common sense. The following suggestions are meant to provide general 

guidance for disposal of hazardous materials: 

— Determine what hazardous materials are being used on-site and which hazardous waste 

streams, if any, are generated as a result of construction activities. Once all of the 

hazardous materials used and hazardous wastes generated are identified, it is possible to 

implement an appropriate waste management and disposal strategy. 

— Know the applicable hazardous waste regulations and the associated requirements for 

storing, marking, and disposing of wastes. Someone on-site should be trained to properly 

manage hazardous wastes. If waste disposal obligations are not clearly understood, 

contact the correct regulatory agency to find out what specific requirements must be 

followed. 

— Use as much of a product as possible before disposing of containers. Containers that are 

not empty but have been stored for disposal can be sources of drips, leaks, or spills, and 

they can contaminate landfills or other disposal areas. 

— Do not remove the original product label from the container. It contains important use, 

safety, and disposal information about the product. 

8.3.4.2 Develop and implement a spill control plan 

Construction sites should be equipped with suitable equipment to contain and clean up spills of 

hazardous materials in the areas where the materials are stored or used. Accidental spills of 

materials used at construction sites can be sources of runoff pollution if not addressed 

appropriately. All spills should be cleaned up immediately after they occur. Creation of a sitespecific spill control and response plan in combination with spill response training for designated 

on-site personnel can be effective in dealing with accidental spills and preventing the 

contamination of soil, water, and runoff. Preparation of a spill containment, control, and 

countermeasures (SPCC) plan might be required to meet regulatory requirements (e.g., 

8-30 
Management Measure 8: Construction Site Erosion, Sediment, and Chemical Control 

requirements regarding storage of specified chemicals above certain volume thresholds). Site 

managers should be aware of all applicable requirements and should contact regulatory 

authorities if requirements are not known. 

Even if a formal plan is not required, preparing one is a good idea. In general, an SPCC plan 

should include guidance to site personnel on the following: 

— Proper notification when a spill occurs; 

— Site responsibility with respect to addressing the cleanup of a spill; 

— Stopping the source of a spill; 

— Cleaning up a spill; 

— Proper disposal of materials contaminated by the spill; 

— Location of spill response equipment programs; and 

— Training for designated on-site personnel. 

A periodic spill “fire drill” should be conducted to help train personnel on proper responses to 

spills and to keep response actions fresh in their minds. 

8.3.4.3 Develop and implement a waste disposal program 

Implementation of good waste disposal practices at construction sites can help to significantly 

reduce the potential for runoff contamination. Wastes generated at construction sites can include 

surplus maintenance chemicals, refuse building materials, hazardous wastes, or contaminated 

soil and spill cleanup materials. General practices to manage such wastes include solid waste 

disposal, recycling, hazardous waste management, and spill prevention and cleanup measures. 

(1) Develop procedures for disposal of construction wastes. Construction projects can generate a 

significant amount of what is commonly referred to as “construction wastes.” Such wastes 

are unique to the activity and might include the following: 

— Trees and shrubs removed during clearing and grubbing; 

— Packaging materials such as wood, paper, plastic, and polystyrene; 

— Scrap or surplus building materials such as scrap metal, rubber, plastic, glass, and 

masonry; 

— Paints and paint thinners; and 

— Demolition debris such as concrete rubble, asphalt, and brick. 

To ensure proper disposal of construction wastes, the following steps should be followed: 

— Select a designated on-site waste collection area. 

— Provide an adequate number of containers with lids or covers that can be placed over the 

containers prior to rainfall. 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

— Locate containers in a covered area when possible. 

— Arrange for waste collection before containers overflow. 

— Explore recycling options for specific wastes generated at the site. Wastes such as used 

oil, used solvents, and construction debris can often be reclaimed or recycled, thereby 

reducing the amount of waste actually requiring permanent disposal. Numerous 

companies can provide recycling services, including the provision and maintenance of 

on-site recycling containers. 

— Implement appropriate response procedures immediately when a spill does occur. 

— Plan for additional containers and more frequent pickups during the demolition phase of 

construction activities. 

— Ensure that all construction wastes are disposed of at facilities authorized to receive such 

wastes. 

(2) Develop procedures for disposal of hazardous products. The correct method of disposal of 

hazardous products varies with the product used. Follow the manufacturer's recommended 

method as printed on the product label. 

(3) Develop procedures for disposal of contaminated soils. Options for disposal of contaminated 

soil depend on the nature of the soil contamination. Under no circumstances should 

contaminated soils be disposed of in adjoining properties or in swamps or other wetlands 

because they will still pose a threat to surface and ground water. The appropriate solid and/or 

hazardous waste regulatory agency should be contacted concerning the proper procedures for 

characterizing, removing, and disposing of contaminated soil. Typically, contaminated soils 

can either be excavated and removed or cleaned on-site. In situ techniques include applying 

chemicals that break down or neutralize the contaminant, venting or sparging the soil to 

oxidize the contaminant, and using biological treatment to metabolize and destroy the 

contaminant. 

(4) Develop procedures for disposal of concrete truck waste. Many construction projects include 

the use of concrete. Usually the concrete is mixed off-site and delivered to the project by 

truck. The concrete is poured and a residual amount of concrete remains in the truck, or the 

concrete is found to be unacceptable and is rejected by the construction inspector or foreman. 

The truck may be cleaned of residual concrete on-site. Excess concrete and wash water 

should be disposed of in a manner that prevents contact between these materials and runoff. 

For example, dikes could be constructed around the area to contain these materials until they 

harden, at which time they can be properly disposed of. 

(5) Develop procedures for disposal of sandblasting grits. Sandblasting is frequently used to 

remove paint and dirt from surfaces. The grit generated contains both the spent blasting grit 

(commonly sand or steel granules) and the particles of paint or dirt removed from the surface. 

Sandblasting residue can be a hazardous waste if the material removed contains hazardous 

metals such as cadmium, lead, and chromium, which are sometimes found in paints. For this 

reason, sandblasting residue should not be allowed to be released to the ground or discharged 

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Management Measure 8: Construction Site Erosion, Sediment, and Chemical Control 

to a storm sewer or sanitary sewer, where it can cause soil or water contamination. Instead, it 

should be evaluated to determine whether it constitutes a hazardous waste. If determined to 

be a hazardous waste, it should be properly handled and disposed of; if not a hazardous 

waste, it should be properly managed and disposed of as a solid waste. Dumping wastes into 

sewers and other drainage channels is illegal and can result in fines or job shutdown 

(USEPA, 1993). 

(6) Develop procedures for disposal of sanitary wastes. Construction sites usually are equipped 

with temporary sanitary facilities such as portable toilets for on-site personnel. Sanitary 

wastes can also be disposed of through septic systems or sanitary sewers. The type of 

facilities used on-site will dictate the appropriate management practices used to deal with the 

wastes. Domestic waste haulers should be contracted to regularly remove the sanitary and 

septic wastes and to maintain the facilities in good working condition. This maintenance will 

help to prevent overloading of the system, which could result in discharges in runoff. All 

septic systems should be installed, operated, and maintained in accordance with appropriate 

regulations. Any discharges to the sanitary sewer systems should be done in accordance with 

local sewer authority regulations. 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

8.4 Information Resources 

EPA’s National Menu of Best Management Practices for Stormwater Phase II developed 

numerous fact sheets describing management practices for construction site operators. The fact 

sheets cover both erosion control and sediment control topics, and they include sections for 

applicability, design considerations, costs, and effectiveness. They are available on EPA’s Web 

site at http://www.epa.gov/npdes/menuofbmps (select “Construction Site Stormwater Runoff 

Control”). 

California’s Storm Water Best Management Practice Handbook: Construction outlines waste 

management practices in a set of fact sheets that include erosion controls (scheduling, velocity 

dissipation devices, slope drains, stream bank stabilization, polyacrylamide, preservation of 

existing vegetation, hydraulic mulch, hydroseeding, soil binders, straw mulch, geotextiles and 

mats, wood mulching, earth dikes, and drainage swales), sediment controls (silt fence, storm 

drain inlet protection, chemical treatment, sediment basins, sediment traps, check dams, fiber 

rolls, gravel bag berms, street sweeping and vacuuming, sandbag barriers, straw bale barriers, 

stabilized construction entrances and exits, stabilized construction roadways, entrance/outlet tire 

washing), and wind erosion control. It can be downloaded in PDF format from 

http://www.cabmphandbooks.org/Construction.asp. 

The Erosion and Sediment Control Field Manual from the San Francisco Regional Water 

Quality Control Board describes management practices for construction site planning and 

management, erosion and sediment control, pollution prevention, and sampling guidelines. 

Descriptions of practices are concise and include full-color graphics and installation information 

including guidelines, timing, and limitations. The manual also includes the new Phase II 

regulations, sampling and monitoring guidelines, and long-term maintenance information. Also 

available are several erosion and sediment control videos (in English and Spanish); guidelines 

for construction projects; a CD training kit for construction site planning and management for 

compliance with NPDES requirements; and the1999 version of the Erosion and Sediment 

Control Field Manual. It can be purchased for $30 at http://store.abag.ca.gov/construction.asp. 

The Kentucky Erosion Prevention and Sediment Control Field Guide from the Kentucky 

Division of Water covers the entire erosion and sediment control process. The guide begins with 

sections on pre-project planning and operational activities and continues with erosion prevention 

and sediment control by starting at the top of the hill, above the project site, and proceeding 

down the slope through the bare soil area, ditches and channels, traps and basins, and to the 

waterways below. The guide can be downloaded in PDF format from 

http://www.water.ky.gov/sw/nps/Publications.htm. 

The Minnesota Local Technical Assistance Program offers courses, videos, and guidebooks 

pertaining to erosion control and drainage. More information about these products can be found 

at http://www.mnltap.umn.edu/. 

There are several research laboratories that conduct independent testing of erosion control 

products. The Texas Transportation Institute’s Hydraulics, Sedimentation, and Erosion Control 

Laboratory conducts side-by-side, full-scale, performance comparisons of roll-type erosion 

control materials and flexible channel liners. Product testing information can be found at 

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Management Measure 8: Construction Site Erosion, Sediment, and Chemical Control 

http://tti.tamu.edu/enviro_mgmt/facilities/hec/. The St. Anthony Falls Laboratory has an “applied 

research” Web page (http://www.safl.umn.edu/research/applied/index.html) with links to studies 

gauging the effectiveness of erosion control products. 

Storm Water Management for Construction Activities: Developing Pollution Prevention Plans 

and Best Management Practices (USEPA, 1992), published by EPA’s Office of Wastewater 

Management, provides summary guidance on the development of storm water pollution 

prevention plans and helps users select appropriate management practices to control erosion and 

sediment loss resulting from construction activities. It was designed to provide technical support 

for construction activities that are subject to pollution prevention requirements under NPDES 

permits for storm water point source discharges. This document can be viewed in PDF format at 

http://www.epa.gov/npdes/pubs/owm0307.pdf or it can be ordered from the National Service 

Center for Environmental Publications (NSCEP) at http://www.epa.gov/ncepihom/index.htm or 

by calling 513-489-8190 (Publication # EPA 833-R-92-001). 

CPESC, Inc. offers certification for erosion and sediment control professionals. This program is 

sponsored by the Soil and Water Conservation Society and the International Erosion Control 

Association to educate field professionals on the best methods for controlling erosion and 

sediment and to provide evidence of professional qualifications. More information about the 

certification program can be found at http://www.cpesc.net. 

The City of Knoxville, Tennessee, developed a manual that describes storm water management 

practices that the city recommends. The manual includes an introduction to storm water 

management practices, a discussion of the theory of erosion control, steps for selecting practices, 

and detailed fact sheets for each practice that include design, inspection, and maintenance 

information. The fact sheets cover four subject areas: activities and methods, erosion and 

sediment, industrial and commercial, and storm water treatment. The manual can be downloaded 

in PDF format at http://www.ci.knoxville.tn.us/engineering/bmp_manual. 

The Delaware Department of Natural Resources and Environmental Control has assembled 

course materials and associated standards and specifications that contain descriptions of 

Delaware's BMPs for erosion, sediment, and runoff control, as well as their certification 

requirements for contractors. These materials, entitled Sediment and Stormwater Management 

Certified Construction Reviewer Course and Associated Delaware State and DOT 

Standards/Specifications, can be obtained by calling 302-739-4411. 

The North Carolina Department of Environment, Health, and Natural Resources (NCDEHNR, no 

date) developed a suite of references pertaining to erosion and sediment control, including the 

Erosion and Sediment Control Planning and Design Manual, which provides extensive details 

and procedures for developing site-specific erosion and sedimentation control plans. The North 

Carolina Erosion and Sediment Control Field Manual is a conveniently sized field reference for 

construction and installation of erosion and sedimentation control measures and devices (does 

not include design charts). The North Carolina Sediment Control Inspector's Guide explains how 

to conduct inspections and evaluate projects, what to look for, and how to interact with 

customers. The North Carolina Erosion and Sediment Control Practices: Video Modules

demonstrate the actual construction of 12 of the most commonly installed erosion and sediment 

8-35 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

control measures. Information for purchasing these materials can be found at the NCDEHNR 

Web site at http://www.dlr.enr.state.nc.us/pages/sedimentation.html. 

The Texas Department of Transportation developed specifications for the use of compost for 

erosion control in the form of temporary erosion control devices and biodegradable erosion 

control logs. These specifications include a description of the practice, materials required, and 

construction, installation, and maintenance of the control. The specifications and other 

information about the use of compost for erosion control can be found at the Texas Department 

of Transportation Web site at 

http://www.dot.state.tx.us/des/landscape/compost/specifications.htm. 

The Composting Council Research and Education Foundation and the U.S. Composting Council 

(no date) developed a manual describing ways in which compost can be used for state highway 

projects. The manual includes case study examples of compost use for slope stabilization, 

vegetation establishment, and erosion and sediment control; compost specifications and 

analytical testing methods; and statistics describing compost usage. Compost Use on State 

Highway Applications can be downloaded in PDF format from 

http://www.epa.gov/epaoswer/non-hw/compost/highway/. 

8-36 
Management Measure 8: Construction Site Erosion, Sediment, and Chemical Control 

8.5 References 

Aicardo, R. 1996. Screening of Polymers to Determine Their Potential Use in Erosion Control on 

Construction Sites. In Proceedings from Conference held at College of Southern Idaho: 

Managing Irrigation-Induced Erosion and Infiltration with Polyacrylamide, May 6–8, 

1996, Twin Falls, Idaho. University of Idaho Miscellaneous Publication No. 101-96. 

American Public Works Association (APWA). 1991. Water Quality: Urban Runoff Solutions. 

The American Public Works Association, Chicago, IL. 

Barrett, M.E., J.E. Kearney, T.G. McCoy, J.F. Malina, R.J. Charbeneau, and G.H. Ward. 1995. 

An Evaluation of the Use and Effectiveness of Temporary Sediment Controls. Technical 

Report CRWR 261, Center for Research in Water Resources, The University of Texas at 

Austin. 

Borroum, S., and M. McCoy. 2000. The California Experience. Civil Engineering July:38–43. 

Brown, W., and D. Caraco. 1997. Muddy Water In—Muddy Water Out? A Critique of Erosion 

and Sediment Control Plans. Watershed Protection Techniques 2(3):393–403. 

Brown, W., and T. Schueler. 1997. The Economics of Stormwater BMPs in the Mid-Atlantic 

Region. Prepared for Chesapeake Research Consortium, Edgewater, MD, by the Center 

for Watershed Protection, Ellicott City, MD. 

Caine, E. 2001. Quilceda-Allen Watershed Erosion Control Program Water Quality Monitoring 

Report. Snohomish County Department of Planning and Development Services, Everett, 

WA. 

California Regional Water Quality Control Board. 1999. Erosion and Sediment Control Field 

Manual, 3rd ed. California Regional Water Quality Control Board, San Francisco Bay 

Region, Oakland, CA. 

Canning, D.J. 1988. Construction Erosion Control: Shorelands Technical Advisory Paper No. 3. 

Shorelands and Coastal Zone Management Program, Washington Department of 

Ecology, Olympia, WA. 

Center for Watershed Protection (CWP). 1997a. Keeping Soil in Its Place. Watershed Protection 

Techniques 2(3):418–423. 

Center for Watershed Protection (CWP). 1997b. Practical Tips for Construction Site Phasing. 

Watershed Protection Techniques 2(3):413–417. 

Center for Watershed Protection (CWP). 1997c. The Limits of Settling. Watershed Protection 

Techniques 2(3):429–433. 

Center for Watershed Protection (CWP). 1997d. Strengthening Silt Fence. Watershed Protection 

Techniques 2(3):424–428. 

8-37 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Center for Watershed Protection (CWP). 1997b. Improving the Trapping Efficiency of Sediment 

Basins. Watershed Protection Techniques 2(3):434–439. 

City of Knoxville, Tennessee. 2001. Best Management Practices (BMP) Manual. City of 

Knoxville, Engineering Department, Stormwater Engineering Division. 

http://www.ci.knoxville.tn.us/engineering/bmp_manual. Last updated March 2001. 

Accessed April 24, 2002. 

Deering, J.W. 2000a. Allowance Item for Soil Erosion and Sediment Control Plan/Measures. 

John W. Deering, Inc., Bethel, CT. 

Deering, J.W. 2000b. Phasing, Sequence, and Methods. John W. Deering, Inc., Bethel, CT. 

Delaware Department of Natural Resources and Environmental Control (DNREC). No date. 

Section 13—Contractor Certification Program. Delaware Department of Natural 

Resources and Environmental Control, Dover, DE. 

http://www.dnrec.state.de.us/newpages/ssregs14.htm. Accessed March 9, 2000. 

Delaware Department of Natural Resources and Environmental Control (DNREC). 1989. 

Delaware Erosion and Sediment Control Handbook. Delaware Department of Natural 

Resources and Environmental Control, Dover, DE. 

Dillaha, T.A., J.H. Sherrard, and D. Lee. 1989. Long Term Effectiveness of Vegetative Filter 

Strips. Water Environment and Technology 1:418–421. 

Entry, J.A., and R.E. Sojka. 1999. Polyacrylamide Application to Soil Reduces the Movement of 

Microorganisms in Water. In 1999 Proceedings of the International Irrigation Show. 

Irrigation Association, Orlando, FL, November 9, 1999, pp. 93–99. 

Environmental Law Institute. 1998. Almanac of Enforceable State Laws to Control Nonpoint 

Source Water Pollution. Environmental Law Institute, Washington, DC. 

Environmental Technology Evaluation Center (EvTEC). 2001. Environmental Technology 

Verification Report for Installation of Silt Fence Using the Tommy Static Slicing Method. 

Environmental Technology Evaluation Center, Civil Engineering Research Foundation, 

Washington, DC. 

Faircloth, W. 1999. Searching for a Practical, Efficient, Economical Sediment Basin. In 

Proceedings of Conference 30, International Erosion Control Association, Nashville, TN, 

February 22–26, 1999, pp. 271–282. 

Franklin County, Florida. 1987. Land Planning Regulations for the Appalachicola Bay Area of 

Critical State Concern. Franklin County Administration Commission, Appalachicola, FL. 

Goldman, S.J., K. Jackson, and T.A. Borstztynksy. 1986. Erosion and Sediment Control 

Handbook. McGraw-Hill, Inc., New York, NY. 

8-38 
Management Measure 8: Construction Site Erosion, Sediment, and Chemical Control 

Goldstein, N. 2002. Compost and storm water management—tapping the potential. BioCycle

(August 2002): 33–38. 

Harding, M.V.. 1990. Erosion Control Effectiveness: Comparative Studies of Alternative 

Mulching Techniques. Environmental Restoration, pp. 149–156. Cited in USEPA. 1993. 

Guidance Specifying Management Measures for Sources of Nonpoint Pollution in 

Coastal Waters. EPA 840-B-92-002. U.S. Environmental Protection Agency, Office of 

Water, Washington, DC. 

Jarrett, A.R. 1999. Designing Sedimentation Basins for Better Sediment Capture. In Proceedings 

of Conference 30, International Erosion Control Association, Nashville, TN, February 

22–26, 1999, pp. 217–234. 

Landschoot, P. 1997. Erosion Control & Conservation Plantings on Noncropland. Pennsylvania 

State University, College of Agricultural Sciences, University Park, PA. 

Loser, J. 2003. Comments on National Management Measures to Control Nonpoint Source 

Pollution from Urban Areas—Draft. U.S. Department of Agriculture, Natural Resources 

Conservation Service. Beltsville, MD. 

Maine Department of the Environment (MDEP). 1999. Maine Department of Environmental 

Protection Issue Profile: Voluntary Contractor Certification Program. 

http://www.maine.gov/dep/blwq/training/ip-vccp.htm. Last updated August 1999. 

Accessed March 9, 2000. 

Metropolitan Washington Council of Governments (MWCOG). 1987. Controlling Urban 

Runoff: A Practical Manual for Planning and Designing Urban BMPs. Metropolitan 

Washington Council of Governments, Washington, DC. 

Millen, J.A., A.R. Jarrett, and J.W. Faircloth. No date. Improved Sedimentation Basin 

Performance with Barriers and a Skimmer. Pennsylvania State University, Agricultural 

and Biological Engineering Department, University Park, PA. 

Minton, G.R., and A.H. Benedict. 1999. Use of Polymers to Treat Construction Site Stormwater. 

In Proceedings of a Conference 30, International Erosion Control Association, Nashville, 

TN, February 22–26, 1999, pp. 177–188. 

National Association of Home Builders (NAHB). 1995. Storm Water Runoff & Nonpoint Source 

Pollution Control Guide for Builders and Developers. National Association of Home 

Builders, Washington, DC. 

National Cooperative Highway Research Program (NCHRP). Primer—Environmental Impact of 

Construction and Repair Materials on Surface and Ground Water. Report 443. National 

Academy Press, Washington, DC. 

Natural Resources Defense Council (NRDC). 1999. Stormwater Strategies: Community 

Responses to Runoff Pollution. Natural Resources Defense Council, New York, NY. 

8-39 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

North Carolina Department of Environment, Health, and Natural Resources (NCDEHNR). No 

date. Technical Assistance: Publications List. 

http://www.dlr.enr.state.nc.us/pages/sedimentation.html. Accessed April 24, 2002. 

Price and Company, Inc. 2004. Case Files: Wal-Mart. 

http://www.priceandcompany.com/case%20studies/Wal-Mart.pdf. Last updated March 

29, 2004. Accessed June 2, 2004. 

Reice, S.R., and R.N. Andrews. 2000. Effectiveness of Regulatory Incentives for Sediment 

Pollution Prevention: Evaluation Through Policy Analysis and Biomonitoring. Prepared 

for the U.S. Environmental Protection Agency by the University of North Carolina, 

Chapel Hill, under EPA Grant No. R 825286-01-0. 

Roa-Espinosa, A., G.D. Bubenzer, and E.S. Miyashita. No date. Sediment and Runoff Control on 

Construction Sites Using Four Application Methods of Polyacryalmide Mix. Dane 

County Land Conservation Department, Madison, WI. 

Schueler, T. 1995. Site Planning for Urban Stream Protection. Metropolitan Washington 

Council of Governments, Washington, DC. 

Schueler, T. 1997. Improving the Trapping Efficiency of Sediment Basins. Watershed Protection 

Techniques 2(3):434–439. 

Smolen, M.D., D.W. Miller, L.C. Wyatt, J. Lichthardt, and A.L. Lanier. 1988. Erosion and 

Sediment Control Planning and Design Manual. North Carolina Sedimentation Control 

Commission, Raleigh, NC. 

Soil Quality Institute (SQI). 2000. Soil Quality—Urban Technical Note No. 1: Erosion and 

Sedimentation on Construction Sites. www.statlab.iastate.edu/survey/SQI/urban.shtml. 

Last updated September 18, 2000. Accessed March 26, 2001. 

Sojka, R.E., and R.D. Lentz, eds. 1996. Managing Irrigation-Induced Erosion and Infiltration 

with Polyacrylamide. In Proceedings from Conference held at College of Southern Idaho, 

Twin Falls, Idaho. May 6–8, 1996. University of Idaho Miscellaneous Publication No. 

101-96. 

Southeastern Wisconsin Regional Planning Commission (SWRPC). 1991. Costs of Urban 

Nonpoint Source Water Pollution Control Measures. Technical Report No. 31. 

Southeastern Wisconsin Regional Planning Commission, Waukesha, WI. 

Stahre, P., and B. Urbonas. 1990. Stormwater Detention for Drainage, Water Quality, and CSO 

Management. Prentice Hall, Englewood Cliffs, NJ. 

Theisen, M. 1996. How to Make Vegetation Stand Up Under Pressure. Civil Engineering News. 

Tyler, R. 2001. Compost filter berms and blankets take on the silt fence. BioCycle (January 

2001). 

8-40 
Management Measure 8: Construction Site Erosion, Sediment, and Chemical Control 

U.S. Army Corps of Engineers (USACE). 1990. Anacostia River Basin Reconnaissance Study. 

U.S. Army Corps of Engineers, Baltimore District, Baltimore, MD. 

U.S. Environmental Protection Agency (USEPA). 1992. Storm Water Management for Industrial 

Activities: Developing Pollution Prevention Plans and Best Management Practices. U.S. 

Environmental Protection Agency, Office of Water, Washington DC. 

U.S. Environmental Protection Agency (USEPA). 1993. Guidance Specifying Management 

Measures for Nonpoint Pollution in Coastal Waters. EPA 840-B-92-002. U.S. 

Environmental Protection Agency, Office of Water, Washington, DC. 

U.S. Environmental Protection Agency (USEPA). 1999. Storm Water Technology Fact Sheet: 

Turf Reinforcement Mats. EPA 832-F-99-002. U.S. Environmental Protection Agency, 

Office of Wastewater Management, Washington, DC. 

U.S. Geological Survey (USGS). 1978. Effects of Urbanization on Streamflow and Sediment 

Transport in the Rock Creek and Anacostia River Basins, Montgomery County, 

Maryland, 1962-74. Professional paper 1003. United States Government Printing Office, 

Washington, DC. 

U.S. Geological Survey (USGS). 2000. Soil Erosion from Two Small Construction Sites, Dane 

County, Wisconsin. USGS FS-109-00. U.S. Geological Survey, Middleton, WI. 

Washington State Department of Ecology. 1989. Nonpoint Source Pollution Assessment and 

Management Program. Document No. 88-17. Washington State Department of Ecology, 

Water Quality Program, Olympia, WA. 

Washington State Department of Ecology. 1991. Stormwater Management Manual for the Puget 

Sound Basin. Public Review Draft. Washington State Department of Ecology, Olympia, 

WA. 

Welsch, J.D. No date. Riparian Forest Buffers: Function and Design for Protection and 

Enhancement of Water Resources. U.S. Department of Agriculture Forest Service, 

Northeastern Area State and Private Forestry, Randnor, PA. 

Wisconsin Legislative Council. 1991. Wisconsin Legislation on Nonpoint Source Pollution. 

Wisconsin Legislative Council, Madison, WI. 

Wishowski, J.M., M. Mamo, and G.D. Bubenzer. 1998. Trap Efficiencies of Filter Fabric Fence. 

Paper No. 982158. American Society of Agricultural Engineers, St. Joseph, MI. 

Woodward-Clyde Consultants. 1991. Urban BMP Cost and Effectiveness Summary Data for 

6217(g) Guidance: Erosion and Sediment Control During Construction. Draft. 

Woodward-Clyde Consultants, Herndon, VA. 

Yu, S., S. Barnes, and V. Gerde. 1993. Testing of Best Management Practices for Controlling 

Highway Runoff. Virginia Transportation Research Council. FHWA/VA-93-R16, p. 60. 

8-41 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Also in Performance of Grassed Swales Along East Coast Highways. Watershed 

Protection Techniques 1(3, Fall):122–123. 

 

8-42 
Management Measure 9: Pollution Prevention 

MANAGEMENT MEASURE 9 

POLLUTION PREVENTION 

9.1 Management Measure 

Implement pollution prevention and education programs to reduce nonpoint source pollutants 

generated from the following activities: 

— The improper storage, use, and disposal of household chemicals, including automobile 

fluids, pesticides, paints, solvents, etc.; 

— Lawn and garden activities, including the improper application and disposal of lawn and 

garden care products, and the disposal of leaves and yard trimmings; 

— Turf management on golf courses, parks, and recreational areas; 

— Commercial activities, including parking lots and gas stations; 

— Improper disposal of pet wastes; and 

— Activities that generate trash. 

9.2 Management Measure Description and Selection 

9.2.1 Description 

This management measure is intended to prevent or reduce nonpoint source pollutant loadings 

generated from a variety of activities within urban areas. Everyday activities of citizens, 

municipal employees, and businesses have the potential to contribute to nonpoint source 

pollutant loadings. These activities include improper use and disposal of household chemicals, 

lawn and garden maintenance, turf grass management, operation and maintenance of diesel and 

gasoline vehicles, illicit discharges to urban runoff conveyances, commercial activities, and 

improper pet waste disposal. Reducing pollutant generation can decrease adverse water quality 

impacts from these sources. 

The practices presented in this management measure are often referred to as source reduction 

practices. They are nonstructural in nature (i.e., they do not require infrastructure) and can be 

used to reduce pollutant generation and maintenance costs. Source control practice costs are 

typically associated with programmatic expenses such as signage, outreach materials, 

workshops, and development and enforcement of ordinances. Although agricultural sources are 

not specifically addressed in this chapter, agricultural sources in an urban or suburban watershed 

should also be considered when developing a pollution prevention plan (see Management 

Measure 1 – Program Framework and Objectives). Source controls for agriculture can be found 

 9-1 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Getting in Step: A Guide to Effective Outreach in Your Watershed

Getting in Step is a guide published by EPA to provide a summary of useful tools for developing and 

implementing an effective watershed outreach plan. The manual uses a step-by-step approach to help 

watershed practitioners address public perceptions, promote management activities, and inform or 

motivate stakeholders. Getting in Step is divided into three parts, as follows: 

— Part I presents the overall framework for developing and implementing an outreach plan. It 

provides specific information about defining goals and objectives; identifying the target 

audience; creating, packaging, and distributing the message; and evaluating the outreach 

plan. 

— Part II provides tips and examples for developing and enhancing outreach materials, with 

emphasis on elements of composition and layout, using artwork and photos, establishing a 

watershed identity, packaging the watershed message, and estimating costs. 

— Part III provides specific tips on working with the news media to gain improved media 

coverage of water quality issues. 

Getting in Step also includes worksheets, graphics for use without permission, and information on 

additional outreach and education resources. The manual is available for download from 

http://www.epa.gov/owow/watershed/outreach/documents/getnstep.pdf or by calling Books on 

Demand at 1-800-521-3042. 

in National Management Measures to Control Nonpoint Source Pollution from Agriculture, 

which can be accessed at http://www.epa.gov/owow/nps/agmm/index.html. 

9.2.1.1 Household chemicals 

Many everyday household chemicals are flammable, combustible, toxic, explosive/reactive, or 

corrosive. If these chemicals are released into the environment, they can pose long-term threats 

to human health, wildlife, vegetation, and other environmental resources. Unlike industrial 

hazardous wastes, not all household chemicals are regulated by federal, state, and local laws. In 

fact, the Federal Resource Conservation and Recovery Act, which regulates hazardous waste, has 

a special exemption for “household hazardous wastes” as defined in the act (Kopel, 1998). It is 

important to note that state and local regulations may be more stringent than federal regulations. 

The Federal Insecticide, Fungicide, and Rodenticide Act regulates the use and disposal of 

pesticides, herbicides, and fungicides through labeling. It is important that users of these 

chemicals follow label instructions carefully, because they provide specific information that help 

prevent harm to human and environmental health. 

The four main avenues for household chemicals to become problem pollutants are through leaks 

and spills, improper use, improper storage, and improper disposal. 

(1) Leaks and spills. Chemicals leaking from improperly maintained automobiles and lawn 

equipment or faulty containers can accumulate on roads, driveways, and lawns and be carried 

by runoff to receiving water bodies. 

9-2 
Management Measure 9: Pollution Prevention 

(2) Improper use. Failure to follow label instructions properly may result in over-application of 

fertilizers or pesticides and can lead to chemical accumulation in the soil and grass. These 

chemicals can leach to ground water or be carried by runoff to surface waters. 

(3) Improper storage. Improper storage of chemicals can lead to spills that can contaminate 

runoff and ground water or result in dangerous chemical reactions. 

(4) Improper disposal. It is a common practice for citizens to pour unwanted chemicals, such as 

detergents, cleansers, or automotive fluids, onto their lawns or driveways or directly down 

storm drains. Contrary to popular belief, most storm sewers do not connect to wastewater 

treatment plants—chemicals disposed of this way could be discharged directly to receiving 

water bodies. Additionally, when chemicals are poured down drains connected to a 

wastewater treatment plant or septic system, they could interfere with treatment systems by 

killing the bacteria that metabolize pollutants, causing water discharged from the plants to be 

contaminated. Ground water is also at risk because runoff can carry these chemicals through 

the soil to the water table. Product labels describe requirements for proper disposal and 

should be followed carefully. 

(5) Outdoor car washing. This activity can result in high loads of nutrients, metals, and 

hydrocarbons being carried to receiving waters during dry weather conditions when the wash 

water flows into the storm drain system. According to surveys, 50 to 75 percent of 

households wash their own cars and 60 percent of those households wash their cars at least 

once a month (Schueler and Swann, 2000b). 

9.2.1.2 Failing septic systems 

Approximately one in four American households relies on a septic system to dispose of their 

wastewater. Septic systems have a failure rate of 5 to 35 percent, depending on soil conditions 

and other factors. When septic systems fail, the untreated or partially treated wastewater 

discharges to surface and ground waters. A survey conducted in the Chesapeake Bay watershed 

found that the average age of septic systems in the area was about 27 years, which is seven years 

beyond the design life of an unmaintained system. About half the owners indicated that they had 

not inspected or cleaned out their system in the previous three years. (Schueler and Swann, 

2000b). 

9.2.1.3 Lawn and garden activities 

Lawn care practices are often targeted by watershed managers as contributors of pesticides and 

nutrients to runoff. A nationwide study by the U.S. Geological Survey (USGS) in 1999 found a 

high incidence of insecticides and herbicides in urban streams. Insecticides commonly used in 

homes, gardens, and commercial areas were found more frequently and in higher concentrations 

in urban streams than in agricultural streams. These concentrations often exceeded guidelines for 

the protection of aquatic life. Herbicides, such as those used for weed control, were found in 99 

percent of sampled streams, but rarely at levels that exceeded guidelines. 

A recent summary of the water quality monitoring efforts by USGS’s National Water Quality 

Assessment Program (2004) revealed high concentrations of pesticides, most commonly 

diazinon, malathion, chlorpyrifos, and carbaryl, in urban waterways; these chemicals were 

 9-3 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

typically found in higher concentrations in urban streams than in agricultural streams. Although 

several of these pesticides are used commonly in household applications, findings in Thornton 

Creek near Seattle suggested that many of the pesticides were from commercial or municipal 

activities because the chemicals are not readily available on the retail market. 

Surveys showed that roughly half of the total diazinon applications in the San Francisco Bay 

Region were to lawns and landscaped areas. In 1995, 27 percent of urban creeks sampled in the 

San Francisco Bay Region demonstrated potentially toxic levels of diazinon (Katznelson and 

Mumley, 1997). Research on diazinon indicates that even proper use, characterized by following 

label instructions, can result in harmful levels of diazinon in urban streams (Schueler and Swann, 

2000d). 

While these results alone do not specify the relative contribution of lawn care activities to urban 

pollution, they do indicate that there is a need for watershed-specific management actions. Many 

aspects of the risks associated with commonly occurring pesticides in the environment are not 

yet clearly understood. Drinking water standards have only been established for 10 of the 75 

pesticides detected by the USGS National Water Quality Analysis, and aquatic life criteria have 

been developed for only six (Graffy, 1998; USGS, 1999). 

Maintaining a healthy lawn might require fertilizers, pesticides, and heavy watering in some 

areas. Overuse of fertilizers, pesticides, and water can lead to excessive growth, increased pest 

problems, and environmental damage. In terms of fertilizer inputs, nutrients typically are applied 

to lawns at about the same rates as for row crops. One study in Marquette, Michigan, indicated 

that nitrogen and phosphorus concentrations in runoff from lawns were five to 10 times higher 

than runoff from other land uses (Schueler and Swann, 2000e). Contrary to popular belief, it is 

possible to achieve a beautifully landscaped yard with judicious use of fertilizers, pesticides, and 

irrigation. A large body of literature by turf researchers shows that healthy and well-managed 

turf grass can actually slow runoff and trap pollutants (Beard and Green, 1994; Schueler and 

Swann, 2000c; USEPA, 1992). The products applied to lawns—fertilizers, pesticides, and 

herbicides—can pollute runoff if label instructions are not properly followed. Studies on the 

characteristics of urban lawns have shown that the soils are often compacted, increasing runoff to 

the point that it is comparable to runoff on some pavements (NCSCS, 2000). Fertilizers contain 

nitrogen and phosphorus, which become pollutants when runoff carries excess fertilizers into 

lakes and streams. Excessive nutrients stimulate algae growth that can lead to death and decay of 

aquatic vegetation due to light and oxygen deprivation. 

Lawns also require physical maintenance in the form of mowing, raking, and removing weeds, 

clippings, and branches. Yard trimmings comprised 12 percent of the total tonnage of municipal 

solid waste generated in 2000, second only to paper products (USEPA, 2002). Alternative 

practices can reduce the quantity of yard wastes generated by lawns and enable reuse of yard 

wastes to extend the capacity of landfills. 

9.2.1.4 Commercial activities 

Runoff from commercial land uses, such as shopping centers, office parks, and parking lots or 

garages may contain high hydrocarbon loadings and metal concentrations that are twice those 

found in the average urban area. These loadings can be attributed to heavy traffic volumes and 

9-4 
Management Measure 9: Pollution Prevention 

large areas of impervious surface on which automotive-related pollutants concentrate (refer to 

Management Measure 7, Bridges and Highways, for a discussion of automobile-related 

pollutants). Other commercial uses, such as vehicle maintenance, liquids storage, and equipment 

storage and maintenance, can also introduce pollutants to runoff. 

In most communities, gas stations are designated as a commercial land use and are subject to the 

same controls as shopping centers and office parks. However, gas stations may generate high 

concentrations of heavy metals, hydrocarbons, and other automobile-related pollutants. Since gas 

stations have high potential loadings and pollutant profiles similar to those of industrial sites, 

good housekeeping controls, such as those used on industrial sites, are recommended. 

Restaurants are sometimes considered hot spots for nonpoint source pollution because they 

generate oils and grease that can contaminate runoff when disposed of improperly. Grease can 

also clog sanitary sewer laterals if sinks are not equipped with grease traps or interceptors, 

resulting in sanitary sewer overflows and increased maintenance of sewer lines. Poor 

housekeeping practices in the outdoor areas of restaurants, such as storing food waste in 

uncovered or leaky garbage bins and dumpsters or hosing off floor mats in the parking lot, can 

cause bacteria, detergents, organic matter, and other pollutants to come into contact with runoff. 

Municipalities can target pollution prevention campaigns to specific commercial activities that 

are suspected of contributing to nonpoint source pollution. Typically, these campaigns involve an 

assessment of commercial facilities to identify the types of waste produced. The campaigns also 

outline methods to reduce the total amount of pollutants generated on-site and to properly 

dispose of pollutants. A set of rules and use limitations that a commercial tenant must agree to as 

a condition of occupying a site can be implemented in commercial covenants, conditions, and 

restrictions. 

9.2.1.5 Pet wastes 

When pet waste is not properly disposed of, it can wash into nearby water bodies or be carried by 

runoff into storm drains. Since most urban storm drains do not connect to treatment facilities, but 

rather drain directly into lakes and streams, untreated animal waste can become a significant 

source of runoff pollution. As pet waste decays in a water body, the degradation process uses 

oxygen and sometimes releases ammonia. Low oxygen levels and the presence of ammonia, 

combined with warm temperatures, can be toxic to fish and aquatic life. Pet waste also contains 

nutrients that promote weed and algae growth. Perhaps most importantly, pet waste carries 

microbes, such as bacteria, viruses, and parasites, that can pose a health risk to humans and 

wildlife. For example, fatalities in sea otters off the coast of California have been traced to a 

protozoan, Toxoplasma gondii, found in cat feces. T. gondii can cause fatal brain infections in 

otters and muscle cysts in humans (Glausiusz, 2002). Pet waste can be controlled through 

enforcement of ordinances (e.g., warnings and citations, public education, signage, and disposal 

containers). 

9.2.1.6 Trash 

Trash and floating debris in waterways have become significant pollutants, especially near urban 

areas where a large volume of trash can be generated in a concentrated area. Trash contributes to 

 9-5 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

visual pollution and detracts from the aesthetic qualities of the landscape. Boaters have 

complained that trash and debris clog engine intake valves and propellers, resulting in expensive 

repairs. Finally, municipalities must incur the cost of clean-up efforts to restore water quality. 

9.2.2 Management Measure Selection 

This management measure was selected to identify ways in which communities can implement 

practices that bring about behavioral changes to reduce nonpoint source pollutant loading from 

the sources listed in the management measure. Such activities include public education, proper 

management of maintained landscapes, source reduction, training and runoff control plans for 

commercial sources, pet waste management activities, and trash control. Communities can select 

practices that best fit local priorities and funding. It is important for the watershed manager to 

note that community acceptance is often the major determinant of whether education and 

outreach activities and administrative mechanisms such as certification and training requirements 

are practical and effective solutions. 

9.3 Management Practices 

9.3.1 Household Chemicals 

A host of biodegradable cleaners and other less-toxic chemicals are commercially available. 

Such alternative products typically contain chemicals that rapidly break down in soil and water 

into fewer toxic constituents, or they are reusable or recyclable. These include low-phosphate or 

phosphate-free detergents and water-based products. These alternative products can be used in 

combination with traditional chemicals as part of an integrated pest management program or for 

everyday household cleaning. Although there may be instances when it is necessary to use 

stronger chemicals (for example, to target bacteria), often a simple, milder cleanser will do the 

job. 

Although alternative products are generally less harmful than commercial cleaners, it is still just 

as important to follow their instructions for proper storage and handling. Alternative products 

and homemade mixtures should be stored in clean, store-bought containers and properly labeled 

to avoid confusion with food or drink (USEPA, no date; USEPA and Perdue University, 1997). 

While some alternative products may claim to be disinfectants, cleaners that are registered as 

disinfectants must meet EPA testing requirements. The EPA’s Source Reduction Alternatives 

Around the Home, which is part of the Consumer Handbook for Reducing Solid Waste, provides 

a brief discussion of alternative cleaning methods as well as proper storage and handling 

procedures (USEPA, no date). 

A 1994 study compared commercial cleaners with various alternative products, including lemon 

juice, vinegar, ammonia, baking soda, and borax. The study found that commercial cleaners were 

more effective than the alternatives at both soil removal and microbial reduction. Alternative 

cleaners were found to achieve soil removal with some additional work. Among the alternative 

cleaners, borax and ammonia were most effective at soil removal. Vinegar was most effective in 

reducing microbial contamination. The study recommended sequential use to maximize cleaning 

effectiveness (USEPA and Purdue University, no date). 

The key to preventing household chemicals from entering receiving waters is to educate the 

public about the importance of taking care when storing and disposing of everyday materials. 

9-6 
Management Measure 9: Pollution Prevention 

The practices discussed below are intended to inform the public on proper procedures for 

handling and disposing of household chemicals to prevent pollution and to instill a sense of 

responsibility for their actions and choices as consumers. 

9.3.1.1 Educate the public on proper storage and disposal of household chemicals 

Watershed managers can produce outreach materials describing methods that citizens should 

follow to store household chemicals in appropriate containers and storage areas to prevent leaks, 

spills, accidental ingestion, and fire or explosion hazards. Tips can include covering piles of 

chemicals that can come into contact with rainfall or runoff; ensuring that containers for volatile, 

corrosive, or otherwise harmful chemicals are intact; and clearly labeling all containers with the 

name of the material and proper storage and disposal procedures. Pesticides, herbicides, and 

fungicides are addressed below in the Pest Management section. 

Citizens should also be encouraged to follow the manufacturer's recommendations for disposal 

of household chemicals. Many communities across the country have implemented programs to 

collect and safely dispose of these chemicals, such as providing year-round collection facilities 

or sponsoring what many communities call “household hazardous waste” collection days. 

Effective outreach programs keep citizens informed about the location and hours of operation of 

disposal facilities and provide a list of waste products that are accepted. 

Recycling of certain household chemicals, especially used oil and batteries, can reduce the 

amount of potentially harmful materials that enter a landfill. Many municipalities and automotive 

service stations provide used oil and antifreeze recycling facilities for “do-it-yourselfers” to 

encourage environmentally sound chemical management. Outreach materials, such as pamphlets 

and utility bill inserts, can be developed to inform the public of locations and hours of operation 

of local recycling facilities. 

9.3.1.2 Conduct storm drain marking 

Storm drain marking involves labeling storm drain inlets with painted or prefabricated messages 

that warn citizens of the environmental hazards of dumping materials into storm drains. Marking 

projects are typically conducted by volunteer groups in cooperation with local authorities. The 

messages can be a simple phrase to remind passersby that the storm drains connect to local water 

bodies and that dumping pollutes those waters. Some specify which water body the inlet drains 

to or name the particular river, lake, or bay. Common messages include “No Dumping—Drains 

to Water Source,” “Drains to River,” and “You Dump it, You Drink it. No Waste Here.” 

Communities with a large Spanish-speaking population might wish to develop markers in both 

English and Spanish or use a graphic without text (Davenport, 2003). 

9.3.1.3 Encourage responsible car washing practices 

Schueler and Swann (2000b) summarized results of several surveys of automobile owners and 

their car washing behavior. The researchers found that 55 to 70 percent of households wash their 

own cars, with the remainder taking their cars to commercial car washes. Sixty percent of 

residents washed their cars at least once a month, and between 70 and 90 percent of residents 

reported that their car wash water drained directly to the street and presumably into the runoff 

conveyance system. These results indicate that an appreciable amount of wash water laden with 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

detergents, dirt, and automotive fluids can wash into the storm drain system or directly into 

receiving waters in urban areas. 

It is preferable for citizens to patronize commercial car washing facilities because they are 

mandated under the regulatory authority of the NPDES program (see the Introduction for a 

description of the NPDES program) to treat and/or reuse wash water, whereas residential car 

washing activities are exempt from requirements under Phase I MS4 permits and Phase II 

general permits (USEPA, 2003b). If commercial facilities are not available or if residents prefer 

to wash their cars themselves, they should be encouraged to wash their cars less often, especially 

in areas with water bodies sensitive to nutrient enrichment. Another practice to reduce the impact 

of car washing on receiving waters is to wash cars on grass or another permeable surface to filter 

dirt and detergents (this practice should be avoided in areas that recharge drinking water 

supplies). Additionally, citizens should use a sponge and bucket to reduce the amount of wash 

water used and to allow it to be disposed of down a household drain that is connected to the 

sanitary sewer or septic system. Finally, low-phosphate detergents should be used to minimize 

the eutrophic effects of wash water in receiving waters. 

Community car washes, such as those conducted for fundraisers, are not specifically addressed in 

Phase II MS4 requirements, but may be a particularly large source of contaminated runoff. Some 

communities are experimenting with fundraiser registration, practices that block storm drains 

during community car washes, and the designation of pervious areas for the diversion of runoff. 

Kitsap County, Washington, uses a patented device called a Bubble Buster to divert water away 

from storm drains during community car washes (USEPA, 2003b). 

9.3.2 Lawn, Garden, and Landscape Activities 

Lawns are a significant feature of urban landscapes. This large area of managed landscape has 

the potential to contribute to urban runoff pollution due to over-fertilization, overwatering, overapplication of pesticides, and direct disposal of lawn clippings, leaves, and trimmings. Also, 

erosion from bare patches of poorly managed lawns contributes sediment to watercourses, and 

disposal of lawn clippings in landfills can reduce the capacity of these facilities to handle other 

types of waste. Public education for citizens and municipal crews with respect to pest tolerance 

and proper handling of fertilizers, pesticides, water, and yard waste can greatly reduce the 

potential for adverse impacts to waters receiving runoff from lawns. Municipalities and 

watershed managers should develop an outreach campaign that targets citizens, lawn care 

businesses, landscapers, and municipal crews. Materials should highlight the following steps to 

help citizens and lawn care professionals maintain healthy, attractive lawns with less 

maintenance and fewer chemical inputs: 

— Lawn conversion 

— Soil building 

— Grass selection 

— Mowing and thatch management 

— Minimal fertilization 

— Weed control and tolerance 

— Pest management 

— Sensible irrigation 

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Management Measure 9: Pollution Prevention 

While all of the above practices are applicable to both citizens and lawn care professionals, they 

will differ when implemented due to differences in scale. For example, lawn care services may 

have multiple employees, carry large quantities of fertilizers and pesticides, and manage vast 

expanses of turf. Therefore, in addition to the above practices, good housekeeping is particularly 

important for lawn care professionals, landscapers, and municipal crews. Housekeeping includes 

implementing materials management and spill prevention plans and conducting employee 

training (see the Commercial Activities section). In addition, site development considerations for 

landscaped areas and golf courses should aim to protect local water bodies by avoiding sensitive 

areas, providing sufficient buffers, and ensuring erosion and sediment control during 

construction and maintenance activities (Center for Resource Management, 1996). See 

Management Measure 3—Watershed Protection and Management Measure 8—Construction Site 

Erosion and Sediment Control for more information about buffers and erosion and sediment 

control, respectively. Information resources specific to citizens and landscape professionals are 

provided at the end of this chapter. 

Local cooperative extension services can provide assistance with the practices described in this 

section. State-specific cooperative extension service information is available from the 

Cooperative State Research, Education, and Extension Service (CSREES) at 

http://www.csrees.usda.gov/qlinks/partners/state_partners.html. Cooperative extensions are part 

of a nationwide organization authorized by Congress, and each state has designated a land grant 

university to administer its cooperative extension. Cooperative extensions conduct applied 

research and educational outreach such as workshops, conferences, fact sheets, and newsletters. 

These organizations are an excellent resource for information and assistance with lawn care 

practices. For example, the Virginia Tech Cooperative Extension Web site, 

http://www.ext.vt.edu/, maintains the Database of Fact Sheets on Home Gardening and 

Insecticides/Pesticides. The Rutgers University Cooperative Extension publishes fact sheets such 

as How to Calculate the Amount of Fertilizer Needed for your Lawn and Best Management 

Practices for Home Lawns (http://www.rce.rutgers.edu/). 

NRCS’s Backyard Conservation 

USDA's Natural Resources Conservation Service (2000) Web site sponsors a Backyard Conservation 

Web site (http://www.nrcs.usda.gov/feature/backyard/) that presents technical information and 

management practices to “increase food and shelter for birds and other wildlife, control soil erosion, 

reduce sediment in waterways, conserve water and improve water quality, inspire a stewardship ethic, 

and beautify the landscape.” The Web site includes 10 conservation practice standards, such as 

composting, mulching, nutrient management, pest management, and terracing, which have been 

modified for use in suburban landscapes. 

9.3.2.1 Lawn conversion 

Grasses are very water-hungry and labor-intensive landscaping plants when compared to ground 

cover, flowers, shrubs, and trees. Therefore, to reduce the maintenance requirements of a lawn 

and address problem areas where turf is difficult to grow, property owners could identify areas 

where turf grass can be replaced with other types of plantings. These areas include lawn edges, 

frost pockets, exposed areas, dense shade, steep slopes, and wet, boggy areas. Replacement 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

vegetation that is best suited to local conditions should be chosen to replace turf. 

Recommendations for drought-tolerant plants are available from a local extension office. Statespecific cooperative extension service information is available from the Cooperative State 

Research, Education, and Extension Service (CSREES) at http://www.csrees.usda.gov. 

9.3.2.2 Soil building 

Lawn owners should analyze their soil every one to three years to determine its suitability for 

supporting a lawn and to identify whether additives are needed or adjustments should be made to 

optimize growing conditions. Soil characteristics that should be measured include pH, fertility, 

compaction, texture, and earthworm content. Soil test kits (for pH and fertility) can be purchased 

inexpensively at a garden center, or samples can be analyzed for free by a local cooperative 

extension service. Soil tests reveal whether fertilizer or lime is needed, helping to avoid overfertilization and loss of nutrients. Surveys have indicated that only 10 to 20 percent of citizens 

test their soil to determine fertilization needs (Schueler and Swann, 2000c). 

Prior to planting, sandy and heavy clay soils may be amended by adding organic compost to 

improve aeration and nutrient-holding capacity. Compacted soil under an established lawn 

should be aerated to improve the flow of water, fresh air, and nutrients to the system. Aeration is 

a non-chemical technique that relieves compaction, increases rooting, helps prevent thatch 

accumulation, incorporates organic matter into the soil surface, and helps prevent damage by 

insects and disease (Troutman, 2003). Core cultivators, which aerate by pulling small plugs of 

soil from the lawn, can be found at many local rental agencies (Mugaas, 1999). Soil texture can 

be determined with a settling test or by squeezing a handful of moistened soil through the fist. If 

soils prove to be very sandy or very clayey, organic matter such as compost, manure, or grass 

clippings should be added (USEPA, 1992). While the presence of earthworms is an indicator of 

healthy soil, the presence of white, healthy roots is the ultimate goal. Rooting can be checked by 

cutting a four-inch deep slice or plug of turf and soil. Roots should be at least four inches deep, 

and the tips should be white. Poor root condition may be a result of compacted soils, ineffective 

watering practices, or poor fertilization (Troutman, 2003). If a lawn does need soil amendments 

(e.g., an adjustment to pH or aeration to address compaction) a local cooperative extension 

service can provide the technical guidance necessary to care for the lawn properly (USEPA, 

1992). State-specific cooperative extension service information is available from the Cooperative 

State Research, Education, and Extension Service (CSREES) at http://www.csrees.usda.gov. For 

more information on soil amendments, see the discussion of Erosion Control Practices in 

Management Measure 8—Construction Site Erosion, Sediment and Chemical Control. 

9.3.2.3 Grass selection 

Grass seed is available in a wide range of cultivated varieties, so citizens are able to choose the 

grass type that grows well in their particular climate, matches site conditions, and is consistent 

with the property owner's desired level of maintenance. Consideration should be given to 

seasonal variations in rainfall and temperature. Several grass varieties have been developed with 

increased resistance to disease and insect damage, which reduces pesticide use. Some turf 

varieties have high levels of endophytes, a fungus that does not threaten the grass but eradicates 

common lawn pests such as billbugs, sod webworms, and aphids. Tall fescue, zoysia grass, and 

Bermuda grass tend to be highly resistant to insects (Audubon Society, 2000). Other varieties 

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Management Measure 9: Pollution Prevention 

have been selected to be slow growing, which requires less mowing, fertilizer, and water. Care 

should be taken to select the species and cultivated variety that are best adapted to the site 

conditions. Selecting the correct variety will result in a healthier lawn that is better able to 

compete with weeds and resist insects and disease (Bruneau, 2001; USEPA, 1992). 

9.3.2.4 Mowing and thatch management 

Each turf grass variety has an ideal mowing height range. Turf grasses use water more efficiently 

and out-compete weeds better when kept at the higher end of the ideal mowing height range. 

Mowing grass too short decreases rooting and increases the need for frequent watering. Tall turf 

competes more vigorously against weeds and can usually tolerate more insect and disease 

pressure (Troutman, 2003). Property owners might need to mow grass more frequently to 

maintain a minimum healthy height, depending on the type of grass planted and the local 

climate. Property owners should understand that grass grows at different rates throughout the 

seasons. As a result, some lawns may need to be mowed every four or five days when they are 

growing rapidly (Troutman, 2003). Therefore, grass should be mowed only as needed. If 

excessive thatch (which can prevent nutrients and water from reaching grass roots) has 

developed, the lawn should be dethatched by raking or using an automated dethatcher, or it could 

be sprinkled with compost and then aerated. Some grasses are more prone to developing thick 

layers of thatch than others. A thatch layer less than 1⁄2 inch can be beneficial by providing 

insulation and increasing the turf’s resiliency (Mugaas, 1999; Murphy, 1994; USEPA 1992). 

To prevent insects and weeds, property owners should mow high and frequently, and keep 

mower blades sharp to avoid tearing or injuring the grass. Longer grass is exposed to more 

sunlight, which allows it to develop a deep root system and increases tolerance to drought, insect 

damage, and disease. Lawns should not be cut shorter than 21⁄2 to 31⁄2 inches because weeds can 

grow more easily in short grasses. Grass can be cut lower in the spring and fall to stimulate root 

growth, but not shorter than 11⁄2 inches (Audubon Society, 2000; USEPA, 1992). Table 9.1 lists 

recommended mowing heights for various types of grasses. 

Table 9.1: Mowing heights for various grass types (PCLAA, No Date). 

Grass Type Mowing Height 

Kentucky Bluegrass 3.0 in. 

Fescues & Ryegrass 3.0 in. 

Bent grass 1.0 in. 

Bermuda grass 1.0 to 1.5 in. 

Zoysia grass 1.0 to 1.5 in. 

St. Augustine grass 3.0 in. 

Bahia grass 3.0 in. 

Centipede grass 1.5 in. 

9.3.2.5 Yard waste management 

Recent concerns about landfill capacity have prompted a number of states to ban the disposal of 

yard waste in landfills (Fickes, 2002). Approximately 3,800 yard waste composting programs 

were operating in the United States during 2000 (USEPA, 2002). Most of these were located in 

the Northeast, Midwest, and South where landfill capacity is of concern and many states have 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Yard Waste Ban 

In Syracuse, New York, a 1992 ban on yard waste disposal resulted in 45 percent of households 

composting yard waste and 55 percent leaving clippings on the lawn. The ban, instituted by the 

Onondaga County Resource Recovery Agency (OCRRA) in North Syracuse, prohibited grass, leaves, 

and brush from being disposed of with the trash. OCRRA has run an eight-year, $300,000 public 

education campaign. OCRAA’s outreach program involves home composting workshops; the 

distribution of flyers, and TV, radio, and newspaper ads with the themes "A Recipe for Compost," 

"Time for a Trim,” and “Keep Your Clippings on the Lawn” (Lalonde, 2000). 

instituted yard waste bans. In the West, where landfill capacity is relatively high and no 

statewide yard waste bans exist, there are only approximately 400 composting programs. 

Yard trimmings accounted for nearly half the municipal waste eliminated or diverted through 

source reduction programs in 2000 (USEPA, 2002). Source reduction has been a successful 

component of municipal waste management, and is a major reason why landfill capacity at a 

national level remains relatively constant. In fact, source reduction is estimated to have 

prevented a 25 percent increase in solid waste in 2000. As of 2000, 34 states had more than 10 

years of landfill capacity remaining, 12 had five to 10 years, and two had less than five years of 

capacity remaining. (USEPA, 2002). 

Yard clippings can be managed by reapplying them to lawns, or by composting at home or at 

community composting facilities. Reapplying clippings to yards, known as grass-cycling, 

reduces solid waste and can decrease the need for fertilizer and water by adding nutrients and 

limiting evaporation. Yard clippings do not contribute to thatch buildup, because thatch is 

comprised of the stems and roots of grass, not the blades (Mugaas, 1999; Relf, 1997). Removing 

a mower’s collection bag is an easy way to automatically incorporate grass-cycling into regular 

mowing activities (PLCAA, no date (a)). Yard waste can also be composted and reapplied to 

improve water retention, add nutrients, and reduce erosion (Relf, 2001). Full bans on disposal are 

not the only option for yard waste management; partial bans and voluntary programs can also 

help to encourage citizens to employ yard waste management practices such as composting and 

leaving clippings on the lawn. Communities can integrate yard waste into their solid waste 

management program by offering curbside collection services or providing public drop-off sites 

(USEPA, 1994). 

9.3.2.6 Minimal fertilization 

Based on the results of the soil test described above, a lawn might require additional nutrients to 

promote or maintain healthy growth. Nutrients can be partly supplied by leaving a moderate 

amount of fine grass clippings on the lawn after mowing—these clippings can provide nearly 

half of the required nutrients to the lawn and they hold in moisture, speed decomposition, and 

relieve the burden of landfills to handle excess yard waste. Additional nutrients can be supplied 

with compost or commercial fertilizers that are of an organic or encapsulated nitrogen type, but 

they should be applied at or below the rates prescribed on the packaging. Compost or organic 

and encapsulated nitrogen fertilizers reduce the risk of nutrient leaching and have been shown to 

release nutrients more gradually. Slow-release fertilizers are also beneficial for reducing nitrogen 

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Management Measure 9: Pollution Prevention 

losses from soils that are prone to leaching (Bureau, 2001). Organic products offer the additional 

benefits of increasing soil condition and promoting the growth of desirable soil organisms. 

Timing of fertilization is very important. Cool-season grasses respond best to fall fertilization 

followed by light applications of fertilizer in the spring. Warm-season grasses generally benefit 

more from spring and summer fertilization. Fertilizers require water for activation; a light 

watering is usually enough (note that fertilizer should not be applied if rainfall is expected). 

Excessive fertilization causes unwanted growth and the need to mow more often. Fertilizing at 

the wrong time of year may favor the growth of weeds rather than healthy turf. Excessive 

fertilization along with excessive watering can lead to the buildup of thatch that can increase 

insect and disease problems (Troutman, 2003). 

The City of Austin recently commissioned Texas A&M University to conduct a study of the 

potential effects of residential lawn care practices on water quality in Stillhouse Spring, located 

in the environmentally sensitive recharge zone of the Northern Edwards Aquifer. Water quality 

tests have shown that nitrate levels in the aquifer are among the highest in the city. Nine different 

fertility treatments on test plots were studied. The plots were tested for appearance and the 

amount of nitrogen, phosphorous, and potassium that leached through the soil to ground water. 

The study resulted in a reevaluation of recommended fertilization practices for citizens. 

Recommendations still include soil testing, careful calculation of fertilizer amounts, and grasscycling. However, researchers found that organically fertilized plots had less nitrogen leaching, 

were denser and more attractive, and were successful in retaining soil moisture and decreasing 

runoff in storm events. Because soils in Austin are particularly high in phosphorus, citizens in 

the area are now advised to use low-phosphorus fertilizers (Provin, 2002). Additional studies of 

residential lawn care practices and regionally specific runoff from urban lawns would be a 

beneficial addition to the large body of research on turf grass. 

A local cooperative extension service should be consulted about the proper use of fertilizers. 

State-specific cooperative extension service information is available from the Cooperative State 

Research, Education, and Extension Service (CSREES) at http://www.csrees.usda.gov. 

9.3.2.7 Weed control and tolerance 

A property owner must decide how many weeds can be tolerated before action is taken to 

eradicate them. A few weeds will not substantially interrupt the continuity of the turf. The best 

way to keep weeds at bay is to maintain a healthy, dense lawn that shades the ground surface, 

preventing weed seedlings from taking root. However, if weeds do take hold, they should be dug 

or pulled out. Chemical herbicides should be used to spot-treat weeds, not applied universally. A 

local cooperative extension service should be consulted about the proper use of herbicides. Statespecific information regarding cooperative extension services is available from CSREES at 

http://www.csrees.usda.gov.

9.3.2.8 Pest management 

Integrated Pest Management (IPM) is an effective and environmentally sensitive approach that 

relies on a combination of common-sense practices. IPM programs use current, comprehensive 

information on the life cycles of pests and their interaction with the environment. This 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Targeted Herbicide Application 

Targeted herbicide application, which uses infrared and other technologies, can help locate and 

control roadside weeds at lower costs than conventional weed control methods (Stidger, 2001). 

Patchen, Inc., which is located in Ukiah, California, manufactures small sensors that can be used on 

trucks or other equipment to pinpoint the location of undesirable plants and then target and spray the 

weed with herbicide. Each sensor views a 12-inch wide area and upon finding weeds, it signals a 

spray nozzle to deliver a precise amount of herbicide. The unit will spray only on weeds and not on 

bare ground. Several California Department of Transportation districts have already mounted the 

sensors onto equipment. According to company reports, a side-mounted strip of sensors at the rear of 

the vehicle lets the unit target and spray roadside weeds at 10 miles an hour. Sensors can be also 

used at night when there is less traffic because the sensors have their own light source. Compared to 

broadcast or manual spot spraying, sensors reduce the quantity of herbicide used and cut overall 

costs by 50 to 80 percent. Sensors also cut costs by reducing required work hours, because only the 

driver is needed to apply the herbicide. 

Research at North Carolina State University (Burton and Skroch, 1997) developed an herbicide 

applicator to attach to weed mowers to control roadside vegetation. The unit applies a film of chemical 

to the weed stem as the mower cuts the plant. Between 70 and 90 percent of the herbicide is 

absorbed into the plant to prevent future growth. With other methods, as much as 80 to 90 percent of 

the sprayed chemical misses its target and is wasted. 

The Minnesota Department of Transportation tested four innovative herbicide sprayer designs in an 

effort to reduce costs. According to a research report, all four sprayers saved money when compared 

to traditional sprayer use. Net annual savings from each of the four sprayers ranged between $23,255 

and $65,812. 

information, in combination with available pest control methods, is used to manage pest damage 

by the most economical means and with the least possible hazard to people, property, and the 

environment. 

IPM is not a single pest control method but a series of pest management evaluations, decisions, 

and controls. IPM is a sustainable approach to managing pests by combining biological, cultural, 

physical, and chemical tools. Biological controls involve the use of natural enemies to manage 

pests. Cultural practices include mowing, fertilization, irrigation, aeration, dethatching, and 

rolling. Physical controls include removal of insects and affected plant material by hand or 

removal of pests with store-bought traps. Chemical controls involve the use of pesticides. 

Municipalities can encourage citizens and lawn care professionals to practice IPM and train 

municipal maintenance crews to use these techniques for public open space. 

Effective pest management begins with maintenance of a healthy, vigorous lawn that is naturally 

disease-resistant. Mulching can be used to prevent weeds where turf is absent; fencing can be 

installed to keep rodents out; and netting can be used to keep birds and insects away from leaves 

and fruit. Planting disease-resistant species and alternating different types of plants can help 

prevent infestation. In addition, simple pest prevention techniques can reduce the likelihood that 

pesticides will be needed. These include destroying hiding places such as diseased plants and 

fallen fruit, cleaning up pet waste, and removing puddles (USEPA, 1995). Citizens should 

monitor plants for obvious damage and should check for the presence of pest organisms. It is 

important to be able to distinguish beneficial insects and arachnids, such as green lacewings, 

ladybugs, and most spiders, from ones that will damage plants. When damage is detected or 

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Management Measure 9: Pollution Prevention 

when harmful organisms are present, citizens should determine the level of damage the plant is 

able to tolerate. No action should be taken if the plant can maintain growth and fertility in the 

presence of these pest organisms. If controls are needed, there is an arsenal of low-impact pest 

management controls and practices to choose from that include preventative measures such as 

planting disease-resistant species and promoting beneficial organisms. See the USDA Regional 

Pest Management Centers Information System Web site at http://www.ipmcenters.org/ for more 

low impact strategies. 

Integrated Pest Management (IPM) combines the use of these lower-impact practices with 

targeted chemical controls. Chemical controls are highly effective but may result in damage to or 

death of desirable species, such as bees. If strong chemical pesticides are applied improperly, 

they can contaminate receiving waters. Several less-toxic pesticide alternatives are available to 

prevent infestations or halt current infestations. Biopesticides, for example, are used to control 

pests without the use of poison. Biopesticides can be “biochemical,” such as garlic and 

pheromones, or “microbial,” such as bacteria, fungi and viruses (USEPA, 2003). Garlic and 

baking soda have been shown to be effective when applied as an aqueous solution to plants. 

Other pest control alternatives include insecticidal soap, which destroys pest membranes, 

Bacillus thuringiensis (a beneficial bacteria found in compost and other organic soil additives), 

milky spore (a natural bacteria that kills the grub phases of Japanese beetles), and dormant oil 

sprays applied when the plants are not growing. When used as a component of IPM programs, 

biopesticides can greatly decrease the need for conventional pesticides. The Biopesticides and 

Pollution Prevention Division in EPA’s Office of Pesticide Programs promotes the use of 

biopesticides as components of IPM programs. The Biopesticides Web site, 

http://www.epa.gov/pesticides/biopesticides, provides information on biopesticide registration, 

active ingredients, product lists, and contact information. 

Municipalities should try to select the least-toxic, least-water-soluble, and least-volatile 

pesticides possible. Pesticides should be evaluated based on their toxicity and their potential to 

run off to surface water or leach into ground water (Peacock et al., no date). Organophosphate 

pesticides, such as diazinon and chlorpyrifos, were popular because they target a broad range of 

pests and they are less expensive than newer, less-toxic pesticides. A risk assessment by EPA has 

determined that chlorpyrifos posed an unacceptable risk to public health, particularly children’s 

health (USEPA, 2000). It was found that diazinon posed unacceptable risks to agricultural 

workers, birds, and other wildlife species. Chlorpyrifos was removed from retail sale and 

residential uses in 2001, and diazinon was phased out in 2004. Synthetic pyrethroids are more 

selective and typically much less toxic than organophosphates, yet they still can harm beneficial 

insects. When applying pesticides such as these, careful and judicious use is recommended to 

avoid harming non-target species. 

Pesticide applicators should always read and follow instructions on the label. Pesticides should 

be applied to minimize drift or runoff, and they should not be sprayed near water sources. 

Application should be avoided during windy conditions or when rain is forecast. Granular 

applications should be avoided or minimized near impervious surfaces and bodies of water. 

Equipment should be checked for proper calibration before pesticide application. After pesticides 

are applied, label directions should be followed to safely dispose of containers. A local 

cooperative extension service can be consulted about the proper use of pesticides. State-specific 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

information regarding cooperative extension services is available from CSREES at 

http://www.csrees.usda.gov.

Pest management methods can also be controlled legislatively. In response to the negative effects 

of many pesticides, some localities are planning to restrict or prohibit the use of certain 

hazardous pesticides (Johnson, 1999). For example, the city of Seattle and King County, 

Washington, intend to stop using pesticides that are deemed most hazardous to control bugs and 

weeds along roads, in parks, and on other public land. The plan will phase out the use of dozens 

of harmful pesticides as the city and county explore less toxic alternatives. Pesticides that will be 

phased out contain known cancer-causing ingredients, seep quickly into ground water or surface 

water, or are labeled highly toxic to birds, fish, or other animals. There will be exceptions to the 

ban on some chemicals, but generally only if there are major health or safety considerations. 

Restrictions on the use of certain pest control products were also implemented in California. In 

1994 a bill was passed that would restrict the sale and use of copper-containing root killers and 

copper and tri-butyl tin-containing cooling tower additives (City of Palo Alto, California, 

Environmental Compliance Division, 1997). These pest control products contribute to the 

Regional Water Quality Control Plant’s exceedances of San Francisco Bay discharge standards. 

When used, these products are discharged to sanitary sewer systems or to storm drains that flow 

untreated to creeks and bays. Because cost-effective alternatives for these products are available, 

the Regional Water Quality Control Plant and other local wastewater treatment plants have urged 

restrictions on the three types of chemicals. In December 1995 the California Department of 

Pesticide Regulation adopted regulations that made it illegal to sell or use copper-based root 

control products and tri-butyl tin-containing cooling water additives within the nine San 

Francisco Bay area counties. These regulations became permanent in November 1996. 

9.3.2.9 Point-of-sale education 

Municipalities and local cooperative extensions can encourage IPM by promoting education at 

the point of purchase. Two studies found that most citizens who apply pesticides used home and 

garden centers as their source of information on pest management (Lajeunesse et al., 1997; Sclar 

et al., 1997). Educating store employees on less-toxic alternatives, keeping less-toxic materials in 

stock, and providing information on the proper use of pesticides will help facilitate the IPM 

process. Czapar et al. (1998) surveyed 656 retail stores in Illinois that sell pesticides. 

Approximately 83 percent of the survey respondents were willing to send employees to a training 

program on pesticides, safe handling practices, and how to recommend appropriate pesticides to 

customers. 

The Bay Area Stormwater Management Agencies Association in the San Francisco Bay Area 

established the “Our Water, Our World” program to educate citizens on less-toxic alternatives to 

pesticides without using negative messages about conventional products. The program consists 

of partnerships with local retail stores that display alternative products and educational materials. 

The program also involves media and advertising campaigns, efforts to institute regulatory 

change, and monitoring of the effects of the program. Initial results from 20 participating stores 

indicated an increase in the sale of less-toxic products and employee satisfaction with the 

associated training programs 

(http://www.epa.gov/oppbppd1/PESP/strategies/2000/basmaa00.htm). 

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Management Measure 9: Pollution Prevention 

Bio Integral Resource Center IPM Partnership Program

The Bio Integral Resource Center (BIRC) in the San Francisco Bay Area has developed a partnership 

between water pollution prevention agencies, nurseries, hardware stores, and the local cooperative 

extension to educate the public on less-toxic pest management. The program focuses on educating 

consumers about pest control products at the point of purchase from nurseries and hardware stores. 

BIRC encourages stores to carry less-toxic products and trains employees on the use of these 

products. 

BIRC also conducts a Healthy Garden Workshop, which is a four-hour public seminar to introduce 

home gardeners to various aspects of IPM such as monitoring, physical controls, horticultural controls, 

and biological controls. Additional topics include water conservation and the use of native plants. An 

illustrated Healthy Garden Handbook accompanies the workshop, and an instructor's guide is 

available to assist others who are interested in giving the class (http://www.pesp.org/2000/birc00-

final.htm). 

Alliance for Chesapeake Bay IPM Partnership Program

The Alliance for Chesapeake Bay IPM Partnership Program promotes IPM by citizens through a 

partnership with retailers in which less-toxic pest control options are labeled with the slogan, "From 

your home to our streams...Choose less toxic products." The program includes employee training 

workshops, IPM informational displays and fact sheets available at participating retail stores. 

Partnerships with garden clubs and Master Gardeners provide training on minimizing environmental 

impacts and less-toxic pest management techniques. 

IPM information displays began appearing in retail locations in central Pennsylvania in March 2003. 

The IPM project is funded by the National Foundation for IPM Education and the Environmental 

Protection Agency. For more information contact: Susan Richards, 717-737-8622, http://www.acbonline.org/project.cfm?vid=89. 

9.3.2.10 Sensible irrigation 

The natural reaction of grasses to drought stress is to become dormant, halting growth, 

conserving resources, and turning dry and brown. In spite of this natural drought tolerance 

mechanism, many property owners strive to maintain lush, green lawns, even in times of dry 

weather. Watering practices vary from a light sprinkling to regular, sometimes excessive, 

automated watering. Underwatering fails to provide water below a few inches of soil, causing 

grasses to be fragile and shallow-rooted. Overwatering promotes excessive growth and humid, 

disease-prone conditions that can damage the lawn. Overwatering can also result in runoff and 

leaching of nutrients (PLCAA, no date (b)). One study found that overwatering increased by five 

to 11 times the amount of nitrogen leached (Morton et al., 1998). 

It is best to water deeply, but not too often. Deep watering encourages the grass to grow deep 

roots, whereas shallow watering maintains shallow roots and reduces the lawn’s ability to retain 

moisture during dry periods (USEPA, 1992). The lawn should be watered only when needed and 

sprinklers should be carefully calibrated to wet the soil to a depth of 6 inches without causing 

runoff. Additionally, watering should be done early in the morning to prevent excessive 

evaporation (USEPA, 1992). Determining and controlling the rate, amount, and timing of 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

watering will reduce soil erosion, runoff, and fertilizer and pesticide movement. An irrigation 

system should be designed to have an average application rate that is less than the infiltration 

capacity of the soil to avoid surface ponding and to maximize water percolation. Trickle and drip 

irrigation systems can save water by more directly irrigating the roots, resulting in less 

evaporation than overhead sprinklers (Relf, 1996). 

Moisture in a home lawn can be retained more efficiently with organic matter, mulch, shade, and 

windbreaks. Organic matter increases the capacity of sandy soils to hold moisture and the 

availability of moisture in clay soils. Mulching helps reduce evaporation and retain moisture and 

humidity. Providing partial shade, particularly in the summer, and blocking wind, can also 

decrease moisture demand (Relf, 1996). 

9.3.3 Commercial Activities 

9.3.3.1 Detect and eliminate illicit connections 

Illicit connections are defined as “illegal and/or improper connections to storm drainage systems 

and receiving waters” (Caraco et al., 1998). A discharge of industrial wastewater to a storm 

sewer is “illicit” because discharges of that type would ordinarily require a permit under NPDES. 

Many building owners and operators are unaware that improper connections exist in their 

facilities. In extreme cases of illicit dumping, legal action is necessary. 

Illicit discharge detection and elimination programs are designed to prevent contamination of 

surface and ground water supplies by monitoring, inspection, and removal of these non-storm 

water discharges, which are illegal if an ordinance has been enacted. These ordinances grant a 

municipality the authority to inspect properties suspected of releasing contaminated discharges 

into storm drain systems. Another important factor is the establishment of enforcement actions 

for those properties found to be in noncompliance or that refuse to allow access to their facilities. 

EPA (1999), in conjunction with the Center for Watershed Protection, published a model 

ordinance for illicit discharges on their model ordinances Web site 

(http://www.epa.gov/nps/ordinance/discharges.htm). The model ordinance includes language to 

address illicit discharges in general as well as illicit connections specifically from industrial sites. 

Municipalities should modify the language to take into consideration enforcement methods that 

are appropriate for the local area. The Center for Watershed Protection (Brown et al., 2004) also 

published Illicit Discharge Detection and Elimination: A Guidance Manual for Program 

Development and Technical Assessments. This publication provides information on costeffective methods to detect and eliminate illicit discharges from municipal storm drains. The 

document is available for download at http://www.cwp.org/PublicationStore/TechResearch.htm. 

Identification of illicit and improper connections is necessary for all sanitary and storm sewer 

systems, especially in areas where pollutants with unknown sources have been detected in 

receiving waters. The level and type of industrial activities and the surrounding land uses will 

affect the methods used to identify illicit connections. 

The following are some practices used to prevent, discover, and eliminate illicit connections: 

− Conducting water quality monitoring and field screening at outfalls and in receiving 

waters to identify areas where pollutant levels are elevated. Consider bacterial source 

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Management Measure 9: Pollution Prevention 

tracking analysis to determine the origins of elevated bacteria levels (see Section 2.3.5 for 

more information about water quality indicators and bacterial source tracking). 

− Instituting building and plumbing codes to prevent connections of potentially hazardous 

pollutant sources to storm drains. 

− Organizing structures to be inspected for illicit connections by building age, with older 

buildings identified as priorities. Businesses whose activities have the greatest potential 

to create sources that could adversely affect water quality and pose human health 

problems also should be given priority. 

− Mapping each area to be surveyed and indicating the route of the sewer system and the 

locations of storm drains on the map. This enables watershed managers to estimate the 

likely locations of illicit connections. 

− Surveying individual buildings to discover where connections to the storm drain exist. 

− Inspecting sewer lines with television equipment to visually identify all physical 

connections. 

− Comparing the results of field tests and video inspections with the known connections on 

the map. Areas with suspected connections should be further investigated. 

− Instituting mandatory inspections for new development, redevelopment, and remodeling 

projects. 

− Removing and testing sediment from catch basins or equivalent structures. 

− Inspecting questionable connections to determine whether they should be connected to 

the storm drain system or to the sanitary sewer. Methods of illicit connection 

identification, such as dye testing, visual inspection, smoke testing, and flow monitoring, 

are described below. 

− Dye testing. Flushing fluorometric dye into suspected connections can be useful to 

identify illicit connections. Once the dye has been introduced into the suspected 

connection, the water in the collection system is monitored to determine whether a 

connection is present. 

− Visual inspection. Remotely guiding television cameras through sewer lines is 

another way to identify physical connections. 

− Smoke testing. Smoke testing is another method used to discover illicit connections. 

Zinc chloride smoke is injected into the sewer line and emerges via vents on 

connected buildings or through cracks or leaks in the sewer line. By monitoring and 

recording where the smoke emerges, crews can identify all connections, legal and 

illegal, to the sewer system. (Mechanisms on drains should prevent the smoke from 

entering buildings; however, in some instances, this will occur. It is important to 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

notify the public that the smoke is nontoxic, though it should be avoided as it can 

cause irritation of the nose and throat in some people.) 

− Flow monitoring. Monitoring increases in storm sewer flows during dry weather can 

lead investigators to sources of infiltration or flow due to illicit connections. 

Rain can hamper efforts to monitor flows and conduct visual inspections. Smoke and dye testing 

are more accurate than visual inspection and are the preferred methods for identifying illicit 

connections. 

The cost of smoke testing, dye testing, visual inspection, and flow monitoring can be significant 

and time-consuming. Site-specific factors, such as the level of impervious area, the density and 

ages of buildings, and land use will determine the level of investigation necessary. Case studies 

in Michigan have estimated the cost of two full-time field staff and other required support to be 

between $182,000 and $187,000 annually (Ferguson et al., 1997). 

An illicit discharge detection program can be an effective method to reduce the quantity of 

pollutants related to industrial and commercial activities that enter the storm drain system. For 

example, the Montgomery County, Maryland, Department of Environmental Protection 

(MCDEP) has an illicit discharge detection and elimination program called “Pipe Detectives” 

that uses volunteer monitoring and community hotlines to identify suspicious discharges 

(MCDEP, 1997). When discharges are reported, DEP consults maps of surrounding areas and 

targets these areas for additional monitoring to narrow the search for the illicit connection. In one 

instance, a “milky white” discharge was reported in an area with many small businesses and 

large apartment buildings. Businesses were sent informational letters advising them of the 

discharge and requesting their assistance in identifying it by allowing MCDEP to survey the 

properties. Through this cooperative effort, three illicit connections were detected and removed, 

including a sink that was used to wash paintbrushes (the source of the milky white discharge). 

The City of Portland, Oregon, addressed illicit discharges from industrial sites by developing a 

memorandum of agreement with the Oregon Department of Environmental Quality, the state 

agency charged with administering municipal storm water permits. The purpose of the agreement 

was to streamline the enforcement process by delegating authority to administer the permits to 

the city. The agreement specified the city’s role in inspections, compliance, and enforcement. 

The first component of the city’s Illicit Discharge Elimination Program involves the 

prioritization of storm water outfalls based on pipe size, land use, historical pollution problems, 

complaints, and monitoring data. These outfalls are subject to dry weather monitoring, and once 

pollutants are detected, upstream investigations are conducted. Second, the Connection 

Verification Program inventoried all connections to the MS4 from individual properties and 

reviewed them for questionable connections. A citizen complaint program and partnership 

agreements facilitate public input and participation and provide a low-cost way to improve 

enforcement efforts (Pronold, 2003). 

The Santa Clara Valley (California) Nonpoint Source Control Program published a guide with 

pollution prevention practices for industrial facilities entitled Best Management Practices for 

Industrial Storm Water Pollution Control (Duke and Shannon, 1992). The guide presents 

21 practices intended to reduce nonpoint source loadings from industrial and commercial 

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Management Measure 9: Pollution Prevention 

activities, including employee and customer training; illicit discharge elimination; waste storage, 

handling, and disposal; equipment inspection and maintenance; facility design features; and 

storm water management. The guide presents detailed technical guidance for common pollutants 

generated by commercial and industrial activities. The Santa Clara Valley Nonpoint Source 

Control Program has other pollution prevention publications that target specific businesses, such 

as automotive repair, construction trades and roadwork, landscape/gardening and pool 

maintenance, mobile cleaners and detailers, and restaurants. Additional information can be 

obtained by contacting the Nonpoint Source Control Program Information Line at 800-794-2482. 

9.3.3.2 Encourage good housekeeping practices at commercial facilities 

One of the best and least-expensive ways to reduce or eliminate pollutants in runoff is to limit 

the exposure of materials that can be eroded or dissolved by rainfall and runoff. An inventory of 

the items on commercial sites that are exposed to rain and runoff provides useful information and 

a starting point for exposure-reduction activities. To help keep rain from contacting pollutants, 

businesses should be advised to keep dumpsters and other containers securely closed, store 

containers under cover, and cover stockpiled materials, such as gravel, wood chips, and building 

materials, with plastic sheeting. Businesses should be asked to clean up their sites, but not by 

washing grit and grime into the storm drain system. Instead they should pick up litter, sweep, 

dispose of sweepings in the garbage (unless they are hazardous and require special disposal), and 

use absorbent materials such as manufactured absorbent snakes, kitty litter, or sawdust to absorb 

oils. 

9.3.3.3 Provide training and education for employees and customers 

Education of employees and customers at commercial sites is key to establishing good pollution 

prevention practices. Training programs provide information on material handling and spill 

prevention and response to better prepare employees in case of an emergency. Employees should 

also be trained on the purpose, operation, and maintenance of pollution prevention management 

practices. Employees can be continually educated with periodic training courses and with signs 

reminding workers of good housekeeping practices. Customers should be informed of efforts to 

Illicit Discharge Elimination Training

The Wayne County, Michigan, Department of Environment’s Illicit Connection/Discharge Elimination 

Training Program provides training for county and local staff responsible for illicit discharge detection 

and elimination. The training program involves technical presentations, "hands on" instruction in 

investigative techniques, and provision of software to aid in program management. Each participant 

receives a notebook containing recommended standard operating procedures and field forms. Stateof-the-art technology is employed, including Global Positioning System (GPS) for locating outfalls and 

a GIS/database software package developed by the County for site investigation. The goal of the 

software package is to promote coordination in reporting/tracking of illicit connections/discharges. The 

training program also instructs participants in the use of chemical analysis field kits for measuring 

water quality parameters. As of September 2002, the program had trained nearly 800 state, local and 

community personnel (Tuomari, 2003; Wayne County Department of Environment, 2001). 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

reduce waste and pollution using signage or pamphlets so they will be less likely to contribute to 

pollution problems that are ultimately the responsibility of the business. 

9.3.3.4 Devise spill prevention, control, and clean-up plans 

The best way to avoid runoff contamination from spilled materials is to prevent the spill from 

occurring. Careful storage of materials in sound, clearly labeled containers, and regular 

inspection and maintenance of equipment, are key practices to prevent spills. Materials stored 

outdoors should be covered and kept on a paved area to protect them from being mobilized by 

wind and runoff. If not roofed, the storage area should be designed to drain with a slight slope 

(approximately 1.5 percent) to an area that will provide treatment prior to disposal. Runoff from 

other areas should be excluded to reduce the volume of runoff requiring treatment by installing 

berms, curbs, or diversions on the perimeter of the storage area. Secondary containment should 

be used when liquids are stored, and runoff or spills from the containment area should be 

directed to the sanitary sewer where permissible or to an appropriate storage or treatment facility 

for reuse or disposal. 

Business managers should develop and post a set of well-defined procedures for handling spills 

of any materials that might be exposed to rainfall or runoff. Procedures should cover small, easyto-handle spills as well as large spills that require employees to contact emergency personnel. 

The procedures should emphasize that spills must be cleaned up promptly and should specify 

how each type of material should be handled. The use of water for clean-up should be strongly 

discouraged. Shop rags should be used for small spills of non-volatile chemicals, and used rags 

should be sent to a professional cleaning service to prevent them from causing a pollution 

problem in a landfill or other disposal area. Larger spills should be absorbed with vermiculite, 

sawdust, kitty litter, or absorbent “snakes.” Disposal methods depend on the hazard level of the 

spilled material. Nonvolatile liquids can be cleaned up with a wet/dry shop vacuum and disposed 

of with the rest of the facility's waste. Drains or inlets to storm sewers should be plugged during 

spill remediation to prevent off-site export of pollutants. 

9.3.3.5 Conduct an environmental audit 

Another approach to pollution prevention at commercial sites is to focus on source reduction, 

which reduces the amount of waste materials that have the potential to contaminate runoff. A 

reduction assessment can be performed to evaluate the type and amount of materials currently 

used, processes conducted, and wastes generated. Such an assessment can provide 

recommendations for modifying the commercial process to generate less waste, using alternative 

raw materials to generate non-hazardous wastes, and identifying recycling options to reduce the 

amount of wastes that require disposal. EPA’s Office of Pollution Prevention and Toxics Web 

site (http://www.epa.gov/oppt/pollutionprevention/) offers technical information and assistance 

about environmental audits for both businesses and state regulatory agencies (USEPA, 2001a). 

9.3.3.6 Practice safe equipment washing and maintenance 

It is important when washing and maintaining equipment to adhere to certain pollution 

prevention measures. The flow of water resulting from cleaning industrial equipment, must be 

discharged as process wastewater to the sanitary sewer and is not allowed in storm drains, in 

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Management Measure 9: Pollution Prevention 

most cases. When cleaning greasy equipment or trucks, a special cleaning area should be 

designated and equipment installed to capture, pre-treat, and discharge the wash water to the 

sanitary sewer. In addition, instructional signs that prohibit changing vehicle oil, washing with 

solvents, and other activities should be posted in non-wash areas. Finally, sumps or drain lines 

should be installed to collect wash water for treatment and discharge to the sanitary sewer. 

Waste materials from vehicle maintenance activities also deserve special attention. Proper 

storage of materials and proper disposal of waste products are imperative. For example, waste 

oil, antifreeze, spent solvents, and some other liquids can be recycled. Spent batteries, however, 

should not be discarded with trash, but must either be disposed of as a hazardous waste or 

returned to the dealer from whom they were purchased. In addition vehicle maintenance should 

be performed in an indoor garage, not in an outdoor parking area. If performing work outdoors, 

all oil and grease should be captured unless precautions are taken to prevent them from being 

carried in runoff, such as with the use of absorbent pads in inlets or grates. 

9.3.3.7 Use care when performing construction, repairs, or remodeling 

When repairing, remodeling, or constructing buildings there are several key techniques that can 

prevent adverse effects on natural systems. Paints should be mixed where spills can be recovered 

or cleaned easily, and an impermeable ground cloth should be used while painting. Paint chips 

and scrapings might contain lead and should be managed properly to prevent contamination of 

water or soil. Paint buckets and barrels of materials should be stored away from contact with 

runoff. During painting clean-up, if a water-based paint was used, brushes and equipment should 

be cleaned in a sink connected to the sanitary sewer; if oil-based paints were used, they should be 

stored or recycled and not be disposed of in the sink or storm drain. Spray painting requires a 

few extra precautions. Temporary scaffolding should be used to hang drop cloths or draperies to 

shield the user from the wind, to collect overspray, and to minimize the spreading of windblown 

materials. Users should be aware of air quality restrictions on spray paints that use volatile 

chemicals and should consider water-based spray paints instead to minimize adverse effects on 

air quality. 

Sand blasting can be controlled to keep particles off of paved surfaces and out of storm drains by 

placing a tarp or ground cloth beneath the work to capture the blasting medium, protect the work 

area from wind, and capture airborne particles. 

9.3.3.8 Proper disposal of pet waste 

Pet owners have several options for properly managing pet waste. Collecting the waste and 

flushing it down the toilet, where it can be treated by a sewage treatment facility or septic tank, is 

the preferred method. Small quantities can also be buried in the yard (when ground water is not 

used in the home), where the waste can decompose slowly. When buried, the waste should be at 

least 5 inches below the ground surface and away from water bodies and vegetable gardens. In 

public areas, the waste can be sealed in a plastic bag and thrown in the trash, which is legal in 

most areas (Water Quality Consortium, 1999). 

Many communities implement pet waste management programs by posting signs in parks or 

other areas frequented by pet owners, sending mailings, and making public service 

 9-23 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Los Angeles County Pet Waste Program

The Los Angeles County Department of Public Works Environmental Programs Division developed a 

program to control pet waste (Lehner et al., 1999). By profiling various groups of pet owners, the 

division identified the best targets for reducing coastal pollution. The program included a multimedia 

campaign to educate new and existing pet owners about the water quality impacts of pet waste. The 

program also distributed clean-up kits to owners and installed plastic bag dispensers in parks. The 

division established partnerships with local pet stores and pet supply companies to promote the 

program. 

announcements. Many communities have “pooper scooper” ordinances that govern pet waste 

clean-up. Some of these laws specifically require anyone who takes an animal off his or her 

property to carry a bag, shovel, or scoop. Any waste left by the animal must be cleaned up 

immediately (Hill and Johnson, 1994). In addition to postings, many communities have installed 

“pet waste stations” in popular dog parks. These stations contain waste receptacles as well as a 

supply of waste collection bags, scoops, and shovels. 

9.3.4 Trash 

When developing control strategies for trash, one should keep in mind the source of the trash and 

the most prevalent types of trash to target ways to control it. Second, the costs for each control 

strategy should be evaluated, and a budget should be developed that takes into consideration the 

services and facilities that are already available. Third, regular cleaning and maintenance of 

storm water control infrastructure is necessary to prevent the accumulation of trash at control 

structures from becoming a hazard. Finally, it is important to understand that control strategies 

should not just transport trash to another water body but should also reduce the quantity of trash 

entering water bodies. 

There are two methods of trash control: source controls and structural controls. There are four 

source control types: community education, improved infrastructure, waste reduction, and cleanup campaigns. Community education, such as informing citizens about options for recycling and 

waste disposal and educating them about the consequences of littering, is one of the best ways to 

reduce the amount of trash that enters runoff control structures and receiving waters. Another 

topic that should be emphasized is proper trash storage and disposal. Improved infrastructure can 

include optimizing the location, number, and size of trash receptacles, recycling bins, and 

cigarette butt receptacles based on expected need. Waste reduction includes encouraging 

consumers to purchase products with less disposable packaging and manufacturers to reduce the 

amount of packaging they use. Finally, clean-up campaigns are an effective way to reduce trash. 

Municipal projects such as street sweeping (see section 7.3.5.1), receptacle servicing, and cleanup crews along roadsides can also be effective in preventing trash from accumulating and 

entering waterways. Municipalities should review their litter control program to determine if the 

number and placement of receptacles is adequate and if regular maintenance activities (e.g., 

sweeping, receptacle servicing) are preventing litter from entering receiving waters. 

Structural controls include physical filtering structures and continuous deflection separation. 

Physical filtering structures concentrate diffuse, floating debris and trash and prevent it from 

traveling downstream. Some examples are trash racks, mesh nets, bar screens, and trash booms. 

Continuous deflection separation targets trash from storm flows during and after heavy 

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Management Measure 9: Pollution Prevention 

precipitation and involves physical separation of solids and floatables from water in runoff 

detention structures. 

The costs for trash controls vary depending on the method employed. For example, the cost of a 

community education program or a plan to increase the number of trash receptacles can be 

minimal, depending on the quality of existing programs and extent of existing infrastructure. On 

the other hand, a structural control strategy can be quite costly. Physical filtering structures, 

including trash racks, bar screens, and silt traps, can range from $250,000 to $1 million or more, 

not including maintenance. A large-scale, continuous deflection separation device for urban 

runoff can cost as much as $3 million (capital cost only). 

9.3.5 Nonpoint Source Pollution Education for Citizens 

Many citizens know very little about nonpoint source pollution. Schueler and Swann (2000a) 

reported that an estimated 41 percent of the population had an idea of what the term “watershed” 

means, and only 22 percent understood that runoff is the most common source of pollution to 

streams, rivers, and oceans. Therefore, watershed and nonpoint source education for citizens is 

important to increase awareness about the environmental consequences of everyday actions. A 

survey of the effectiveness of outreach programs showed that media campaigns and intensive 

training of target audiences are the most effective ways to effect change in citizen behavior (up 

to 10 percent change in behavior in target populations). Specifically, TV ads and programs, 

newspaper ads, radio ads, and direct mail campaigns were shown to be the most influential and 

memorable messages to the public. Table 9.2 provides a summary of cost information and target 

audiences for various outreach methods. 

Table 9.2: Select cost and audience information for various outreach techniques (Worlton, 

2003). 

Element Cost Unit Audience 

Flyers $0.40–$1.20 Each Limited by requests 

Fact Sheets $0.40–$1.20 Each Limited by requests 

Radio $2,000 or more Per station 500,000–2,000,000 

Television $2,400 or more Per month 250,000–500,000 per day 

Billboards $700 Per board 6,800 per day 

Markers $2.94 Each 0–5,000 per day 

Trailers $165 Per theater 5,000 or more per day 

Schueler and Swann (2000a) recommend the following techniques to effectively market a 

watershed message: 

− Present a simple, direct watershed message, repeat it frequently, use multiple types of 

media, and emphasize the connection between the message and a local water body. 

− Develop awareness of the connection between yards, streets, storms, and streams. 

− Pool resources with other local or regional organizations to expand the campaign’s 

budget. 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

− Use cable network and public television channels for commercials and targeted TV 

programs to more effectively reach target audiences. 

− Focus the campaign on one or more target audiences. Many communities are ethnically 

and culturally diverse, and a portion of the population speaks languages other than 

English, which requires a campaign specifically tailored to the local demographics. 

Communities can also direct messages to children or focus efforts towards reaching the 

disadvantaged, who otherwise might not have the opportunity to learn about or 

participate in programs and activities. A survey of watershed demographics and problem 

pollutants should be conducted to better identify target populations. 

− Keep the message simple and humorous and develop durable, attractive, non-technical 

outreach materials. 

− Educate and partner with private-sector companies such as septic tank cleaners, 

commercial car washes, and oil change franchises. 

9.3.5.1 Use multilingual nonpoint source messages 

Many communities are ethnically and culturally diverse, and a portion of the population speaks 

languages other than English. The messages contained in signs, brochures, advertisements, 

newsletters, and other outreach materials that are printed only in English are mostly lost on these 

groups. For example, in areas such as southern Florida and southern California, where a large 

proportion of the population consists of Spanish-speaking immigrants, it is important to reach out 

to non-English-speaking residents and inform them about storm water pollution issues and the 

importance of clean water, because their activities can generate a substantial amount of pollution. 

This type of expanded outreach program is not limited to these areas. Census 2000 figures show 

increasing minority populations in urban centers and suburbs such as Washington, DC 

(Fernandez, 2001; Cohn and Witt, 2001), and New York (Cohn, 2001), among others. 

Outreach materials can be printed in multiple languages based on the demographics of a 

community. The North Central Texas Council of Governments (NCTCOG), as part of its 

pollution prevention and public awareness campaign, printed articles, press releases, brochures, 

flyers, and bill stuffers in both English and Spanish (NCTCOG, 2000). The University of Texas 

at Austin designed and installed storm drain markers in both English and Spanish (University of 

Texas at Austin, 1997). 

9.3.5.2 Use classroom education to deliver nonpoint source messages 

Providing nonpoint source education to children through schools delivers the educational 

message not only to students but to their parents as well, because children often take home what 

they learn. Watershed managers have partnered with educators and experts to develop storm 

water-related curricula for the classroom. Fortunately, these lessons need not be elaborate or 

expensive to be effective. 

An example of this type of education is the Children’s Water Festival in Albuquerque, New 

Mexico. Several hundred fourth-grade students from schools in the area engaged in hands-on 

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Management Measure 9: Pollution Prevention 

earning activities about water science, history, geography, and drama. The Albuquerque-based 

Ciudad Soil and Water Conservation District used its “Rolling River” educational model to show 

how all the components of a watershed are connected and how changes in one part affect others. 

Students created a mini-river, purified water from the Rio Grande, and built aquifers from edible 

ingredients. They also used a computer model to make projections of water use in the future and 

a ground water model to see how water moves underground. Students analyzed water samples 

and played the roles of algae, fish, and raptors to understand how toxins can travel through the 

food chain. They created wetlands, simulated flood and drought situations, changed the 

infrastructure, and then observed the effects of their manipulations. 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

9.4 Information Resources 

9.4.1 General 

The Center for Watershed Protection published Illicit Discharge Detection and Elimination: A 

Guidance Manual for Program Development and Technical Assessments. This publication 

provides information on cost-effective methods to detect and eliminate illicit discharges from 

municipal storm drains. The document is available for download at 

http://www.cwp.org/PublicationStore/TechResearch.htm. 

EPA’s GreenScapes program provides cost-efficient and environmentally friendly solutions for 

large-scale landscaping. GreenScapes encourages companies, government agencies, and other 

entities to make more holistic decisions regarding waste generation and disposal. The 

GreenScapes program emphasizes four elements: reduce, reuse, recycle, and re-buy. More 

information about the GreenScapes program can be found at the program’s Web site at 

http://www.epa.gov/greenscapes. 

EPA’s Office of Solid Waste has released “A Collection of Solid Waste Resources” on CDROM. This resource contains more than 300 publications on hazardous and non-hazardous 

waste; documents are listed by topic and are searchable, and some documents are in both English 

and Spanish. More information about this CD-ROM is available at EPA’s Office of Solid Waste 

Web site at http://www.epa.gov/epaoswer/osw/cdoswpub.htm. 

EPA’s Used Oil Management Program developed the “You Dump It, You Drink It” campaign 

aimed to educate the Hispanic automotive repair and service industry and consumers about the 

impacts of improper disposal of used oil. The campaign includes posers, brochures, and bumper 

stickers in both English and Spanish. These materials, a description of the Used Oil Management 

Program, and relevant publications, rules, notices, regulations, and links can be found at 

http://www.epa.gov/epaoswer/hazwaste/usedoil/index.htm. 

Appropriate Technology Transfer in Rural Areas (ATTRA) published the guidance Integrated 

Pest Management: Fundamentals of Sustainable Agriculture, which provides a basic 

understanding of IPM for individuals interested in agriculture. It incorporates the steps that need 

to be taken prior to IPM implementation, the tools used, and some ideas about future trends for 

IPM. The ATTRA publication is available at http://www.attra.org/attra-pub/ipm.html (Dufour 

and Bachmann, 1998). 

The City of Seattle’s ProIPM (Seattle Public Utilities, 2000) is the Green Gardening Program’s 

series of IPM fact sheets for landscaping professionals. The fact sheets were designed to assist 

landscapers in the field and when explaining the IPM approach to clients. Each provides 

essential facts about various northwestern United States pest or disease problems, including 

information regarding pest identification, life cycle information, monitoring, damage threshold, 

and treatments. The fact sheets are available for download at 

http://www.seattle.gov/util/Services/Yard/For_Landscape_Professionals/Integrated_Pest_Manag

ement/index.asp or by calling the Green Gardening Program at 206-547-7561. The ProIPM Web 

site also provides information about proper disposal methods for pesticide products. 

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Management Measure 9: Pollution Prevention 

The U.S. Air Force’s PRO-ACT program is an environmental research service and information 

exchange clearinghouse (PRO-ACT, 2000). PRO-ACT’s Integrated Pest Management Fact 

Sheet provides information regarding IPM policy and guidance, typical components of an IPM 

program, control techniques available to pest managers, and management practices that can be 

implemented in an IPM program. The fact sheet is available at 

http://www.afcee.brooks.af.mil/pro-act/fact/intpst.asp. PRO-ACT may be contacted by phone at 

800-233-4356 or by e-mail at pro-act@hqafcee.brooks.af.mil. 

The USDA Regional Pest Management Centers Information System Web site 

(http://www.ipmcenters.org/) provides information about agricultural commodities, pests, and 

pest management practices, as well as links to each of the four Regional Pest Management 

Centers. Users can access the complete Crop Profiles and Pest Management Strategic Plans 

databases, an IPM Expertise database, information on pesticide use, current pest management 

research, funding opportunities, and links to related sites. Additional region-specific information, 

news, and announcements can be found at the regional Web sites. 

NRCS (no date) has prepared a backyard conservation tip sheet that provides the public with 

information on pest management. The tip sheet helps readers to identify the problem, to know 

what to look for, and to control various types of pests with mechanical, physical, biological, and 

chemical control strategies. The NRCS tip sheet is available at 

http://www.nrcs.usda.gov/feature/backyard/pdf/PestMgt.pdf. 

The International Turf Producers Foundation (ITPF, no date) recently published Water Right: 

Conserving Our Water, Preserving Our Environment. The publication provides information 

about a variety of water topics, including water use and conservation, environmental and 

economic benefits of responsible landscape management, and landscape water conservation 

techniques. The document is available for download at 

http://www.turfgrasssod.org/waterright.html or can be obtained by contacting ITPF at 1855 

Hicks Road, Suite C, Rolling Meadows, Illinois, 60008; 847-705-9898 or 800-405-8873. 

Audubon Magazine published The Audubon Guide to Home Pesticides in 2000. This guide 

provides citizens with a list of popular pesticides, along with their typical uses, their toxicity to 

humans and wildlife, EPA’s toxicity rating, and alternatives for each of the chemicals. The guide 

is available for download at http://www.magazine.audubon.org/pdf/pesti_chart.pdf. 

The Pest Management Branch of the California Department of Pesticide Regulation published 

Suppliers of Beneficial Organisms in North America. The publication lists 143 commercial 

suppliers of 130 beneficial organisms that are used for biological control. Suppliers are located in 

Canada, Mexico, and the United States. The booklet is available for download at 

http://www.cdpr.ca.gov/docs/ipminov/bensuppl.htm. 

The EXtension TOXicology NETwork (EXTOXNET) is a joint effort of the University of 

California at Davis, Oregon State University, Michigan State University, Cornell University, and 

the University of Idaho. EXTOXNET provides a variety of information about pesticides, 

including discussions of toxicological issues of concern; toxicology newsletters, fact sheets, and 

information briefs; pesticide information profiles; and other resources for toxicology 

information. The network can be accessed at http://ace.orst.edu/info/extoxnet. 

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The National Pesticide Telecommunication Network is a cooperative effort of Oregon State 

University and the U.S. Environmental Protection Agency. The network is a source of chemical, 

health, and environmental information about more than 600 pesticide active ingredients 

incorporated into at least 50,000 different products registered for use in the U.S. since 1947. The 

toll-free telephone service (800-858-7378) provides information about pesticide products, 

recognition and management of pesticide poisoning, toxicology, and environmental chemistry to 

any caller in the United States, Puerto Rico, or the Virgin Islands. 

Nonpoint Education for Municipal Officials (NEMO) is an educational program created by the 

University of Connecticut for local land use decision-makers that addresses the relationship 

between land use and protection of natural resources, particularly water resources. NEMO is an 

award-winning program that uses remote sensing, geographic information systems, and Internet 

technologies. The NEMO model is being adapted around the country, and NEMO projects are 

being planned and implemented by various agencies and organizations. This nationwide group, 

under the leadership and coordination of the University of Connecticut NEMO Project, is called 

the National NEMO Network. Additional information about NEMO is available at 

http://www.nemo.uconn.edu/. 

Organic Gardening magazine and Web site (http://www.organicgardening.com/) provide 

information about organic pest control and help users find soil-testing labs in their area. 

Riversides is a Canadian nonprofit organization that promotes source control and nonpoint 

source pollution prevention strategies. An important component of the Riversides Web site is 

H2infO: The Water Information Network, which provides information about current campaigns, 

resources, and services offered by the network. Also offered are listservers and links to agencies, 

associations, and non-governmental organizations. The H2infO Web site can be accessed at 

http://www.h2info.org/. Also, H2infO can be contacted at 590 Jarvis Street, Suite 200, Toronto, 

Ontario, Canada, M4Y 2J4; phone 416-392-1757; fax 416-960-9944; e-mail input@H2infO.org. 

EPA’s Biopesticide Web site provides users with specific information about biopesticides, 

including fact sheets, decision documents, product lists, labels, company lists, study reviews, 

bibliographies, regulatory information, and federal register notices. The Web site can be 

accessed at http://www.epa.gov/pesticides/biopesticides. 

EPA (1995) published the Citizen’s Guide to Pest Control and Pesticide Safety, which provides 

users with important information about pesticides, including steps to control pests in and around 

the home; alternatives to chemical pesticides; methods for choosing, using, storing, and 

disposing of pesticides; how to reduce exposure when others use pesticides; how to choose a pest 

control company; and what to do if someone is poisoned by a pesticide. The guide is available at 

http://www.epa.gov/oppfead1/Publications/Cit_Guide/citguide.pdf. 

EPA (1999) published Education Projects in the Office of Water: A How-to Guide for 

Developing Environmental Education Projects. The document provides a road map for creating 

quality environmental education projects and outlines EPA’s procedural guidelines for producing 

a product or supporting related projects already in existence. It also lists publications, contacts, 

and references, including Web sites, training opportunities, and available materials, that provide 

the reader with further detail and insight into the process of developing effective environmental 

9-30 
Management Measure 9: Pollution Prevention 

education pieces. A list of agencies and organizations that have water-related environmental 

education programs and projects is provided in an appendix. The publication is available from 

EPA’s National Service Center for Environmental Publications Web site at 

http://www.epa.gov/ncepihom. It can also be ordered by phone, fax, or mail from 

USEPA/NSCEP, P.O. Box 42419, Cincinnati, Ohio 45242-2419; toll-free 800-490-9198; fax 

513-489-8695. 

The Commonwealth of Kentucky published Turfgrass: Best Management Practices for 

Protection of Water Resources (USEPA, 2001b). The manual provides information and guidance 

on turf grass management practices that decrease adverse effects on water resources. Information 

about the manual, along with a list of commonly used best management practices for turf 

management, is available at http://www.epa.gov/Region4/water/nps/projects/ky94-2.htm. 

The Council of State Governments (1999) published Getting in Step: A Guide to Effective 

Outreach in Your Watershed. The guide presents a step-by-step approach for developing and 

implementing an effective watershed outreach plan. Getting in Step is available for download in 

PDF format at http://www.epa.gov/owow/watershed/outreach/documents/getnstep.pdf or by 

calling Books on Demand (800-521-3042). 

State-specific cooperative extension service information is available from the Cooperative State 

Research, Education, and Extension Service (CSREES) at http://www.csrees.usda.gov/. 

The California Peer Review Project, funded by the California Integrated Waste Management 

Board, compiles and reviews scientific research on the health effects, environmental effects, and 

efficacy of alternative household products. The project allows interested parties to participate 

during the review process, and findings from these literature reviews are available for download 

on the Web site (http://www.peerreview.com/). 

The Stormwater Quality Management Committee, sponsored by the Clark County Regional 

Flood Control District in Las Vegas, Nevada, has developed a Web site devoted to its campaign 

to prevent pollution from urban runoff. The site has a number of resources for developing 

education and outreach materials, including examples of a bus stop shelter ad campaign, public 

service announcements, brochures, and community presentations at 

http://www.lvstormwater.com/. 

The EPA’s Web site, Yard Trimmings/Food Scraps, provides basic information on the 

environmental and economic benefits of recycling yard waste and food scraps. It also includes 

descriptions of practices for citizens, links to case studies, and technical fact sheets. The site can 

be accessed at http://www.epa.gov/epaoswer/non-hw/muncpl/yard.htm. 

In 1994 the EPA published Composting Yard Trimmings and Municipal Solid Waste, a 151-page 

manual on the inclusion of composting as part of an integrated solid waste management program. 

It provides guidance on program development, facility siting and design, and costs and benefits, 

and includes information on many helpful resources. This manual can be downloaded in PDF 

format at http://www.epa.gov/epaoswer/non-hw/compost/cytmsw.pdf. 

The Region 4 DoD Pollution Prevention Partnership published Best Management Practices 

Resource Guide—Household Hazardous Waste to guide pollution prevention activities on 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

military bases, but the information is applicable to any pollution prevention initiative. It includes 

guidance on proper management of household chemicals, as well as descriptions of applicable 

state and federal laws, regulations and reporting requirements, and state resources. It describes 

various types of collection programs, lists resources for disposal and recycling by material type, 

and includes examples of outreach and education materials. The resource guide is available in 

PDF format at http://www.p2pays.org/ref/13/12935.pdf.

9.4.2 Yards: General Resources 

The Bay Area Water Pollution Prevention Agency’s “Our Water, Our World” program published 

Less-Toxic Pest Management: Problem Pesticides, a fact sheet describing the current state of 

chlorpyrifos and diazinon regulation, as well as some additional pesticides of concern. It 

provides information on alternative pest management techniques and sources of additional 

information. The site can be accessed at 

http://www.ci.livermore.ca.us/wrd/pdf_files/pesticides.pdf. 

The National Foundation for IPM Education (NFIPME) is a non-profit organization that 

promotes education, provides information, and encourages research on integrated pest 

management. The Web site, http://www.ipm-education.org/, contains links to sponsored 

programs and information on grants for pesticide environmental stewardship. 

Robert Mugaas at The University of Minnesota Cooperative Extension published Responsible 

Fertilizer Practices for Lawns. The paper provides soil-specific information on fertilizer 

application practices to protect water quality. It can be accessed at 

http://www.extension.umn.edu/distribution/horticulture/DG6551.html. 

9.4.3 Yard Resources for Homeowners 

Water Quality and Home Lawn Care, by the North Carolina State University Cooperative 

Extension, takes citizens through the process of establishing a healthy lawn and maintaining it 

using practices that protect water quality. It provides specific instructions on watering, mowing, 

and fertilization. This fact sheet can be downloaded in PDF format from 

http://www.turffiles.ncsu.edu/PUBS/MANAGEMENT/HOMELAWN.PDF. 

The U.S. EPA publication Healthy Lawn, Healthy Environment is a user-friendly brochure that 

describes lawn care practices for citizens. It covers the basic principles of soil building, mowing 

techniques, appropriate thatch buildup, and IPM. The brochure also discusses important 

considerations for citizens in selecting a professional lawn care service. The brochure can be 

downloaded in PDF format from http://www.epa.gov/oppfead1/Publications/lawncare.pdf. 

9.4.4 Yard Resources for Lawn Care Professionals 

The University of Florida Cooperative Extension maintains a database of fact sheets for lawn 

care professionals, Professional Lawn and Landscape Fact Sheets. The fact sheets cover athletic 

fields, golf courses, roadsides, interiorscapes and non-residential lawns. The fact sheets can be 

downloaded from http://edis.ifas.ufl.edu/TOPIC_Professional_Lawn_and_Landscape. 

The North Carolina State University Cooperative Extension’s fact sheet, Water Quality & 

Commercial Lawn Care, is a resource for lawn care professionals on fertilizer, mowing, and 

irrigation practices. It includes information on the leaching potential of specific chemicals, turf 

9-32 
Management Measure 9: Pollution Prevention 

grass selection, and fertilizer use. The fact sheet is available in PDF format at 

http://www.turffiles.ncsu.edu/pubs/new/commcare.pdf.

The North Carolina State University Cooperative Extension has published Pest Control for 

Professional Turfgrass Managers. This document includes information on proper use and 

leaching potential for commonly used insecticides and herbicides. It provides information on 

tolerance and disease resistance for turf grass species. It is available for free download in PDF 

format from http://ipm.ncsu.edu/AG408/turfgrass.pdf. 

Water Quality for Golf Course Superintendents and Professional Turf Managers, produced by 

the North Carolina State University Cooperative Extension, describes lawn care practices that 

help to protect water quality. The discussion covers turf grass selection, IPM, mowing, and 

fertilizer practices that are specific to commercial lawn care. The fact sheet is available as a PDF 

at http://www.turffiles.ncsu.edu/PUBS/MANAGEMENT/PROTURF.PDF. 

North Carolina State University Cooperative Extension’s fact sheet, Water Quality and Pesticide 

Selection for Professional Turf Managers, provides guidance on the chemical selection process 

and information on leaching potential and toxicity for herbicides, insecticides, and fungicides. 

The fact sheet is available as a PDF at 

www.turffiles.ncsu.edu/PUBS/MANAGEMENT/PESTFORMAT1.PDF. 

The Cooperative Extension at Rutgers State University maintains an online Database of 

Commercial Turfgrass and Landscape Maintenance Fact Sheets, a resource for lawn care 

professionals. It is accessible at 

http://www.rce.rutgers.edu/pubs/subcategory.asp?cat=5&sub=35. 

The Golf Course Superintendents Association of America (GCSAA) has developed a set of 

principles for the protection of water quality in golf course planning and siting, design, 

construction, and maintenance. These principles and practices are summarized in the online 

publication, Golf and the Environment. It can be accessed at 

http://www.gcsaa.org/resources/facts/principles.asp.

The Professional Lawn Care Association of America’s Grasscycling Guide describes 

recommended mowing heights for various grass types, the benefits of recycling grass clippings, 

and simple techniques for returning grass clippings to lawns. The guide is available in PDF 

format at http://turf.ufl.edu/BMPmanual.pdf. 

The Florida Department of Environmental Protection produced Best Management Practices for 

Protection of Water Resources in Florida to provide guidance on specific lawn care industry 

practices to protect water quality. The manual covers practices such as employee training, 

irrigation system design, the design and installation of landscapes, and irrigation system 

maintenance. It explains techniques for mulching, mowing and pruning, material disposal, 

fertilizer application, IPM, and spill prevention. It is available for download in PDF format at 

http://miami-dade.ifas.ufl.edu/programs/fyn/publications/PDF/GI-BMP6-20-02.pdf.

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9.5 References 

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Barth, C.A. 1995. Toward a low input lawn. Watershed Protection Techniques 2(1):254–264. 

Beard, J.B. and R.L. Green. 1994. The Role of Turfgrasses in Environmental Protection and their 

Benefits to Humans. Journal of Environmental Quality 23:452-460. 

Brown, E., D. Caraco, R. Pitt. 2004. Illicit Discharge Detection and Elimination: A Guidance 

Manual for Program Development and Technical Assessments. Center for Watershed 

Protection, Ellicott City, MD. 

Bruneau, J.H. 2001. Water Quality & Commercial Lawn Care. North Carolina State University 

Cooperative Extension. 

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September 5, 2003. 

Burton, J., W. Skroch, and T. Lucas. 1997. Scientists Devise New, Safer Way to Apply Roadside 

Herbicides. 

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Californians for Alternatives to Toxics (CATs). 2000. Arcata Pesticide Ordinance. Californians 

for Alternatives to Toxics. http://www.alternatives2toxics.org/catsoldsite/ordinance.htm. 

Accessed August 2, 2001. Last updated Spring 2000. 

Caraco, D., R. Claytor, P. Hinkle, H.Y. Kwon, T. Schueler, C. Swann, S. Vysotsky, and 

J. Zielinski. 1998. Rapid Watershed Planning Handbook. Center for Watershed 

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Center for Resource Management. 1996. Environmental Principles for Golf Courses in the 

United States. Salt Lake City, Utah. 

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City of Palo Alto, California, Environmental Compliance Division. 1997. Urban Pesticide 

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Cohn, D. 2001, March 16. Immigration fueling big U.S. cities. The Washington Post, p. A1. 

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Post, p. A1. 

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Management Measure 9: Pollution Prevention 

Czapar, G. F., Curry, M. P., & Lloyd, J. E. 1998. Survey of Integrated Pest Management training 

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Johnson, T. 1999. City, county to reduce their pesticide use: Most-hazardous poisons will be 

largely avoided. Seattle Post-Intelligencer. 

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Area: Occurrence and Potential Impact. Woodward Clyde Consultants and California 

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management practices, water quality awareness, and preferred learning methods. Journal 

of Natural Resources and Life Sciences Education, 26(1) 43-48. 

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Morton, T.G., A.J. Gold, and W.M. Sullivan. 1988. Influence of Overwatering and Fertilization 

on Nitrogen Losses from Home Lawns. Journal of Environmental Quality, 17(1):124-

130. 

Mugaas, R.J. 1999. Lawn Care Practices to Reduce the Need for Fertilizers and Pesticides. 

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horticulture/DG5890.html. Accessed June 12, 2003. 

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Murphy, J.A. 1995. Turfgrass Seed Selection for Home Lawns. Rutgers University Cooperative 

Extension. http://www.rce.rutgers.edu/pubs/publication.asp?pid=FS684. Accessed June 

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Management Measure 9: Pollution Prevention 

Natural Resources Conservation Service (NRCS). No date. Backyard Conservation Tip Sheet: 

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for Professional Turf Managers. North Carolina State University Cooperative Extension. 

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11, 2003. 

PRO-ACT. 2000. Integrated Pest Management Fact Sheet. http://www.afcee.brooks.af.mil/proact/fact/intpst.asp. Accessed July 31, 2001. 

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Roberts, E., and B. Roberts. 1989. Lawn and Sports Turf Benefits. The Lawn Institute, Pleasant 

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Schueler, T. and C. Swann. 2000e. Stormwater Pollution Source Areas Isolated in Marquette, 

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Schueler, T., and C. Swann. 2000b. Understanding watershed behavior. Watershed Protection 

Techniques 3(3):671–679. 

Schueler, T., and C. Swann. 2000c. Urban Pesticides: From the Lawn to the Stream. Watershed 

Protection Techniques 2(1):247–253. 

Schueler, T., and C. Swann. 2000d. Diazinon Sources in Runoff from the San Francisco Bay 

Region. Watershed Protection Techniques 3(1): 613-616. 

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practices in Colorado: A survey of woody plant nurseries and citizens, 1995-1996. Tech. 

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Stidger, R.W. 2001. Vegetation management: sprayer designs target herbicide application, cut 

costs. Better Roads May: 26–30. 

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Nonpoint Source Pollution from Urban Areas. ValleyCrest Companies, Sanford, FL. 

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U.S. Environmental Protection Agency (USEPA) and Purdue University. 1997. I’d Rather Do It 

Myself. USEPA Region 5 and Perdue University Department of Agricultural & 

Biological Engineering. 

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2001. Accessed September 5, 2003. 

U.S. Environmental Protection Agency (USEPA) and Purdue University. 1996. How Well do 

they Work? Report on the Research Project “Household Cleaners and the Environment.” 

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Management Measure 9: Pollution Prevention 

USEPA Region 5 and Perdue University Department of Agricultural & Biological 

Engineering. http://www.purdue.edu/dp/envirosoft/housewaste/src/research.htm. Last 

updated May 7, 2001. Accessed September 5, 2003. 

U.S. Environmental Protection Agency (USEPA). 1992. Healthy Lawn, Healthy Environment: 

Caring for Your Lawn in an Environmentally Friendly Way. 700-K-92-005. Office of 

Prevention, Pesticides and Toxic Substances. 

http://www.epa.gov/oppfead1/Publications/lawncare.pdf. Accessed June 11, 2003. 

U.S. Environmental Protection Agency (USEPA). 1994. Composting Yard Trimmings and 

Municipal Solid Waste. EPA 530-R-94-003. http://www.epa.gov/epaoswer/nonhw/compost/cytmsw.pdf. Accessed July 1, 2003. 

U.S. Environmental Protection Agency (USEPA). 1995. Citizen Guide to Pest Control and 

Pesticide Safety. EPA 730-K-95-001. Office of Prevention, Pesticides, and Toxic 

Substances. http://www.epa.gov/OPPTpubs/Cit_Guide/citguide.pdf. Accessed July 22, 

2003. 

U.S. Environmental Protection Agency (USEPA). 1999. Model Ordinances to Protect Local 

Resources: Illicit Discharges. http://www.epa.gov/nps/ordinance/discharges.htm. Last 

updated October 27, 1999. Accessed June 30, 2000. 

U.S. Environmental Protection Agency (USEPA). 2000. Chlorpyrifos Revised Risk Assessment 

and Agreement with Registrants. Office of Prevention, Pesticides and Toxic Substances. 

http://www.epa.gov/oppt/pollutionprevention/. Accessed July 22, 2003. 

U.S. Environmental Protection Agency (USEPA). 2001a. Pollution Prevention Technical 

Assistance. http://www.epa.gov/p2/assist/index.htm. Last updated November 23, 2001. 

Accessed April 8, 2002. 

U.S. Environmental Protection Agency (USEPA). 2001b. Turfgrass: Best Management Practices 

for Protection of Water Resources. http://www.epa.gov/region4/water/nps/projects/ky94-

2.htm. Last updated May 21, 2001. Accessed January 22, 2002. 

U.S. Environmental Protection Agency (USEPA). 2002. Municipal Solid Waste in the United 

States: 2000 Facts and Figures. EPA 503-R-02-001. http://www.epa.gov/epaoswer/nonhw/muncpl/pubs/report-00.pdf. Accessed June 11, 2003. 

U.S. Environmental Protection Agency (USEPA). 2003a. Regulating Biopesticides.

http://www.epa.gov/pesticides/biopesticides/index.htm. Last updated April 30, 2003. 

Accessed June 11, 2003. 

U.S. Environmental Protection Agency (USEPA). 2003b. Managing Car Washing. Nonpoint 

Source News-Notes (70). Washington, DC. 

U.S. Environmental Protection Agency. No Date. The Consumer’s Handbook for Reducing Solid 

Waste. http://www.epa.gov/epaoswer/non-hw/reduce/catbook/alt.htm. Last updated 

November 6, 2002. Accessed June 11, 2003. 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

U.S. Geological Survey (USGS). 1999. The Quality of Our Nation’s Waters: Nutrients and 

Pesticides. USGS Circular 1225, Washington DC. 

http://water.usgs.gov/pubs/circ/circ1225/. Accessed June 11, 2003. 

U.S. Geological Survey (USGS). 2004. Water Quality in the Nation’s Streams and Aquifers—

Overview of Selected Findings, 1991–2001. Circular 1265. U.S. Geological Survey, 

Reston, VA. 

University of Texas at Austin. 1997. NPDES Storm Water Management Program. 

http://www.utexas.edu/safety/ehs/water/swmp_6_2000.PDF. Last updated June 12, 2000. 

Accessed August 20, 2001. 

Water Quality Consortium. 1998. Surface Water Quality: What's the Problem with Pet Waste?

http://www.ci.seattle.wa.us/util/surfacewater/bmp/petwaste.htm. Last updated November 

18, 1998. Accessed April 5, 2001. 

Wayne County Department of Environment. 2001. Illicit Discharge Elimination Services Offered 

by the Watershed Management Division, Wayne County Department of Environment. 

http://www.waynecounty.com/doe/watershed/idep.htm. Accessed July 30, 2003. 

Worlton, M. 2003. Overcoming Challenges in Regional Public Education & Outreach 

Partnerships. Paper presented at the National Conference on Urban Storm Water: 

Enhancing Programs at the Local Level, February 17-20, Chicago, IL. 

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Management Measure 10: Existing Development 

MANAGEMENT MEASURE 10 

EXISTING DEVELOPMENT 

10.1 Management Measure 

Develop and implement watershed management programs to reduce runoff pollutant 

concentrations and volumes from existing development and redevelopment: 

— Identify opportunities to reduce pollutants in priority local and/or regional watersheds 

(e.g., improvements to existing urban runoff control structures, including the addition of 

infiltration, filtration, retention, and detention practices). 

— Devise a schedule for implementing appropriate runoff controls. 

— Limit destruction of natural conveyance systems. 

— Where appropriate, preserve, enhance, or establish buffers along surface water bodies and 

their tributaries. 

— Promote redevelopment that reduces runoff volumes and pollutants. 

10.2 Management Measure Description and Selection 

10.2.1 Description 

The purpose of this management measure is to protect or improve surface water quality by 

developing and implementing watershed management programs that pursue the following 

objectives: 

— Reduce surface water runoff pollution loadings from areas where development has 

already occurred. 

— Reduce the volume and peak runoff rates of surface water runoff to reduce runoff flow, 

increase infiltration, and minimize habitat degradation and sediment loadings from 

erosion of streambanks and other natural conveyance systems. 

— Preserve, enhance, or establish buffers that provide water quality benefits along water 

bodies and their tributaries. 

Maintaining water quality becomes increasingly difficult as urbanization occurs and areas of 

impervious surface increase. Increased peak runoff volumes from impervious surfaces result in 

alteration of stream channels, natural drainageways, and riparian habitat. This alteration, in turn, 

results in elimination or reduction of predevelopment aquatic flora and fauna and degradation of 

predevelopment water quality. Other effects include increased bank cutting, streambed scouring, 

embedded cobbles, siltation, increases in instream water temperature, decreases in dissolved 

oxygen, and changes to the natural structure and flow of the stream or river. 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Protecting water quality in urbanized areas is difficult because of many factors, including diverse 

pollutant loadings, large runoff volumes, limited areas suitable for surface water runoff treatment 

systems, the high implementation costs associated with structural controls, and the destruction or 

absence of buffer zones that can filter pollutants and prevent the destabilization of streambanks 

and shorelines. 

An important nonstructural component of many watershed management plans is the 

establishment and preservation of buffers and natural systems (e.g., by policy, code, or 

ordinance). These areas help to maintain and improve surface water quality by filtering and 

infiltrating urban runoff. In areas of existing development, natural buffers and conveyance 

systems may have been altered as urbanization occurred. Where possible and appropriate, 

additional impacts on these areas should be minimized, and if the areas are degraded, their 

functions should be restored. Establishing and protecting buffers is most appropriate along 

surface water bodies and their tributaries where water quality and the biological integrity of the 

water body are dependent on the presence of an adequate buffer or riparian area. Buffers may be 

necessary where the buffer or riparian area: 

— Reduces significant nonpoint source pollutant loadings; 

— Provides habitat necessary to maintain the biological integrity of the receiving water; 

— Reduces undesirable thermal impacts on the water body; or 

— Reduces erosion. 

Structural practices may be a suitable option to decrease the nonpoint source pollution loads 

generated from developed areas in addition to nonstructural controls (see Management Measure 

9: Pollution Prevention). In such situations, a watershed plan can be used to integrate the 

construction of new surface water runoff treatment structures and to retrofit existing surface 

water runoff management systems. 

Retrofitting is a process that involves the modification of existing surface water runoff control 

structures or surface water runoff conveyance systems that were initially designed to control 

flooding, not to serve a water quality improvement function. By enlarging existing surface water 

runoff structures, changing the inflow and outflow characteristics of such devices, and increasing 

runoff detention and retention time, sediment and associated pollutants can be removed from the 

runoff. Retrofit of structural controls is often the only feasible alternative for improving water 

quality in developed areas. Where existing development or financial constraints limit treatment 

options, targeting or identifying priority pollutants and selecting the most appropriate retrofits 

that will result in the greatest improvement to water quality may be necessary. 

Once key pollutants have been identified, an achievable water quality target for the receiving 

water should be set to improve current levels based on an identified objective or to prevent 

degradation of current water quality. Extensive site evaluations should then be performed to 

assess the performance of existing surface water runoff management systems and to pinpoint 

low-cost structural changes or maintenance programs for improving pollutant removal 

efficiency. Where flooding problems exist, source controls, low-impact development (LID), and 

infiltrative controls should be incorporated into the design of surface water runoff controls. 

Available land is often limited in urban areas, and the lack of suitable areas frequently restricts 

the use of conventional pond systems. In heavily urbanized areas, sand filters, biofilters, or water 

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Management Measure 10: Existing Development 

quality inlets with oil/grit separators might be appropriate for retrofits because they do not limit 

use of the land. 

10.2.2 Management Measure Selection 

The first and second components of this management measure were selected to encourage 

communities to develop and implement watershed management programs. Local conditions, 

availability of funding, and problem pollutants vary widely among communities. Watershed 

management programs allow communities to select and implement the practices that best address 

local needs. Prioritizing local and/or regional pollutant reduction opportunities and setting 

schedules for implementing appropriate controls were selected as logical starting points for 

establishing an institutional framework to address nonpoint source pollutant reduction. The first 

two parts of Section 10.3: Management Practices, “Identify, Prioritize and Schedule Retrofit 

Opportunities” and “Implement Retrofits as Scheduled” address these two components. 

The third and fourth components of this management measure were selected to preserve, 

enhance, and establish areas within existing development, such as natural streams, ponds, and 

wetlands and aquatic buffers, that provide positive water quality benefits. These natural systems 

provide efficient runoff conveyance as well as aesthetic benefits. These components are 

addressed by the third, fourth, and fifth parts of Section 10.3: Management Practices: “Restore 

and Limit the Destruction of Natural Runoff Conveyance Systems,” “Restore Natural Streams,” 

and “Preserve, Enhance, or Establish Buffers.” 

The fifth component is addressed by part 5 of Section 10.3: Management Practices, “Revitalize 

Urban Areas.” This component was selected to encourage redevelopment of urban areas that may 

be contributing to water quality problems via impervious surfaces, contaminated soils, or land 

uses that result in poor runoff quality or increased runoff volumes. Multiple goals such as surface 

water and ground water quality improvement, soil remediation, and quality-of-life enhancements 

may be simultaneously achieved using such an approach. 

The Brownfields program, managed by EPA under the authority of the Small Business Liability 

Relief and Brownfields Revitalization Act of 2002 (USEPA, 2002b), promotes redevelopment of 

these areas and also can be an effective source of funding and expertise to achieve the above 

goals. The Act 

— Provides legislative authority for the Brownfields program including grants for 

assessment and clean-up; 

— Expands the current Brownfields program by increasing its funding authority up to $200 

million per year including up to $50 million per year to assess and clean up brownfields 

with petroleum contamination; 

— Expands eligibility for assessment and clean-up grants; 

— Includes a new provision for direct clean-up grants of up to $200,000 per site; 

— Streamlines current requirements for the brownfields clean-up revolving loan fund and 

makes funding available to nonprofit organizations; 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

— Applies the Davis Bacon Act, which maintains local wage and labor standards for federal 

construction work, on the same terms as the authority for the current program; and 

— Makes funds available for technical assistance, training, and research. 

More information about the Small Business Liability Relief and Brownfields Revitalization Act 

can be found at http://www.epa.gov/brownfields/sblrbra.htm. 

Cost was a major factor in the selection of this management measure. EPA acknowledges the 

following constraints to implementing nonpoint source controls for existing development: 

— High costs and other limitations inherent in treating existing sources to levels consistent 

with the standards set for developing areas; 

— Frequent lack of suitable areas for structural treatment systems that can adequately 

protect receiving waters; 

— Lack of universal cost-effective treatment options; 

— Frequent lack of funding for mandatory retrofitting; and 

— Extraordinarily high costs associated with implementing retention ponds and exfiltration 

systems in developed areas. 

10.3 Management Practices 

10.3.1 Identify, Prioritize, and Schedule Retrofit Opportunities 

In the watershed assessment phase of the urban runoff management cycle, watershed managers 

should identify water bodies that have been degraded by urban runoff and prioritize them for 

restoration based on the costs and benefits for watershed stakeholders. One method to halt 

further degradation and initiate water body recovery is to retrofit existing runoff management 

practices or conveyance structures. It is important for watershed managers to have clear goals 

and realistic expectations for retrofitting existing structures. Each retrofit project should be 

planned in the context of a comprehensive watershed plan, and managers should have a clear set 

of objectives to ensure that the project results in measurable improvements in hydrologic, 

habitat, and/or water quality indicators. 

10.3.1.1 Evaluate existing data 

The first step in identifying candidate sites for storm water retrofitting is to examine existing 

data. These data can include results from a watershed assessment, topographic maps, land use or 

zoning maps, property ownership maps, aerial photos, and maps of the existing drainage 

network. For example, results from a watershed assessment can be used to identify areas with 

good habitat and water quality that should be protected, as well as areas with poor habitat and 

water quality that need to be improved. Topographical maps can be used to delineate drainage 

units within the watershed at the subwatershed and catchment levels. Land use or zoning maps 

can be used to estimate areas of high impervious cover to target areas that contribute a large 

amount of runoff to receiving waters, while property maps provide land ownership data. Finally, 

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Management Measure 10: Existing Development 

aerial photographs can be used to identify open spaces that can be more easily developed into 

runoff management facilities. According to the Center for Watershed Protection (CWP, 1995a), 

the best retrofit sites: 

— Are located adjacent to existing channels or at the outfall of storm drainage pipes; 

— Are located within an existing open area; 

— Have sufficient runoff storage capacity; 

— Are feasible for diverting runoff to a potential treatment area (forested or vegetated area) 

or structural management practice; and 

— Have a sufficient drainage area to contribute meaningfully to catchment water quality. 

Specific areas well-suited for new runoff controls include undeveloped parkland and open space, 

golf courses, wide floodplains, highway rights-of-way, and edges of parking lots. 

Information for potential retrofit sites, such as location, ownership, approximate drainage area, 

utility locations, and other pertinent details, can be compiled in a retrofit inventory sheet (CWP, 

1995a). A site visit can provide information on site constraints, topography, adjacent sensitive 

land uses, receiving water conditions, utility crossings, and other considerations that would affect 

the feasibility of implementing the management practice. At this point, a conceptual sketch for 

rerouting drainage and siting management practices should be drawn and preliminary cost 

estimates made for each site. 

10.3.1.2 Choose appropriate management practices based on site conditions 

The choice of one potential retrofit site over another for management practice implementation 

can be based on several different factors in addition to site limitations and cost. For instance, the 

preliminary goals of a retrofit program may be to preserve streams or reaches known to have 

high-quality habitat or exceptional water quality. The goal of another program may be to restore 

poor habitat and degraded water quality. The program may elect to target particular land uses 

thought to contribute the majority of pollutants to receiving waters. Retrofit facilities also can be 

installed to treat runoff from large parts of a watershed or subwatershed (regional controls), 

thereby requiring fewer overall projects. Once retrofit sites are identified and prioritized, a 

schedule for installing new facilities or updating old facilities should be devised. 

10.3.1.3 Incorporate low-impact development practices into existing development 

In many cases, sites that are already developed can be retrofitted with low-impact development 

practices such as biofilters, rain barrels, rooftop greening, and cisterns (see Management 

Measure 5 for a more detailed discussion of these practices). Soil rehabilitation and tree planting 

can also contribute to the reduction of runoff. All of these practices can be designed on a small 

scale to accommodate space constraints that may be present on developed sites. The use of these 

practices will aid in retaining runoff on-site and help to reduce the total volume of runoff 

reaching receiving waters. For example, in Washington, DC, trees have saved $4.74 billion in 

gray infrastructure costs per 30-year construction cycle, and reduced the need for storm water 

retention structures by 949,000 ft3 (NALGEP, 2003). 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

The City of Chicago has incorporated low-impact development practices such as rooftop 

greening and downspout disconnection into its urban runoff management strategy. The City Hall 

Rooftop Garden is a $1.5 million retrofit project to demonstrate the benefits of green roofs. The 

city has published A Guide to Rooftop Gardening 

(http://www.cityofchicago.org/Environment/GreenTech/pdf/GuidetoRooftopGardening.pdf) to 

communicate the lessons learned from this project and provide information to the public on 

green roof development. The city is also targeting flood-prone areas for its downspout 

disconnection campaign, distributing door hangers and brochures to residents, and encouraging 

the use of rain barrels (Murante, 2003). 

The Low-Impact Development Design Strategies: An Integrated Design Approach (Prince 

George’s County, Maryland, Department of Environmental Resources, 2000) and the Low 

Impact Development Center Web site (http://www.lowimpactdevelopment.org/) can provide 

more information about these and other practices appropriate for existing developments. 

Additionally, a search for “urban forestry” on the USDA Forest Service’s Web site 

(http://www.fs.fed.us/) produces many good references about how trees can be used to reduce 

runoff volume and improve runoff quality. 

10.3.1.4 Identify undeveloped and privately owned land for acquisition 

In addition to the installation of conventional storm water management practices, the acquisition 

and preservation of open space in developed watersheds can protect against the threat of further 

development, reduce runoff volume, and provide storm water treatment. This practice involves 

the identification of parcels in a developed watershed that are undeveloped or privately owned 

and can be protected or restored to provide storm water benefits by attenuating additional runoff 

volume and peak flow. This watershed-wide planning effort involves mapping open space, 

cadastral data (e.g., property boundaries, subdivision lines, buildings), drainage systems, urban 

forests, floodplains, and other land use data. The planning effort also involves selecting sites 

based on their proximity to receiving waters, the condition of the soil and vegetation, and ease of 

purchase. Selected parcels are purchased, restored if necessary, and modified to receive and 

retain more runoff using berms or diversions (O’Leary, 2003). For more information on land 

acquisition, see Management Measure 3: Watershed Protection. 

10.3.1.5 Use routine maintenance as an opportunity for retrofitting existing 

infrastructure 

One of the major challenges in controlling runoff from existing development is the potentially 

high cost of retrofitting infrastructure to reduce runoff quantity and improve quality. One way to 

reduce costs is to modify runoff controls during routine maintenance procedures. Retrofits can be 

constructed as part of the routine maintenance and repair of urban infrastructure. This approach 

requires less capital outlay for retrofit compared to large-scale, capital-intensive approaches. For 

example, pervious surfaces can be installed when resurfacing parking areas, and newly disturbed 

areas can be restored to the desired vegetative condition (e.g., forest or meadow). When storm 

water ponds are dredged every few years, sediment forebays can be redesigned to improve 

performance. 

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Management Measure 10: Existing Development 

Retrofitting Catch Basins for On-Street Runoff Storage

An example of a retrofit to reduce downstream impacts of urbanization can be found in the towns of 

Skokie and Wilmette, Illinois. These towns are urban areas that are served by a combined sewer 

system (CSS). Both communities wanted to control CSS surcharge but did not want to build expensive 

relief sewers. As a result, they were willing to try alternative approaches. The towns decided to modify 

street cross sections and storm drain inlets to allow runoff to be stored temporarily on the street 

surface during storm events to reduce hydraulic loading to CSSs. The street surface storage projects 

combined the following elements (USEPA, 2000b): 

— Street storage. 

— Downspout disconnection. 

— Flow regulators. 

— Subsurface storage. 

— New storm and combined sewer systems. 

— Improvements to existing storm and combined sewer systems. 

The projects involved installing a system of street berms, 7 to 9 inches high, at the curb line to detain 

water on the street. Flow regulation devices were installed at catch basin outlets to reduce the rate of 

storm water flow to the CSS. Both the street surface and the inlet structure were used for storage. 

Subsurface storage facilities were also installed in the street right-of-way and in other public areas at 

critical points in the system and in pedestrian walkways, parking areas, and high-traffic areas, where 

ponding was unacceptable. 

The project resulted in a number of benefits. Researchers estimated a cost savings from using street 

storage rather than conventional sewer separation systems. Estimated costs for the Skokie system 

are approximately 38 percent of conventional sewer separation system costs. Berm costs are a small 

fraction of the overall cost of the CSS surcharge relief project. Another benefit of the storage system is 

traffic control. Berms can function as speed humps and help control traffic. The street storage system 

also reduces the volume and frequency of combined sewer overflows, resulting in less runoff-related 

pollution entering receiving waters. Icing of ponded areas during the winter was not a problem 

because retention times were relatively short (less than 30 minutes), but consideration should be 

given to safety hazards associated with ponded water during periods of high rainfall. 

10.3.2 Implement Retrofit Projects as Scheduled 

CWP (1995b) describes six common types of retrofitting projects: 

— Modifying existing runoff management facilities; 

— Constructing new management practices at the upstream end of road culverts; 

— Constructing new management practices at storm drainage pipe outfalls;. 

— Constructing small instream practices in channels; 

— Constructing management practices at the edge of large parking areas and 

— Constructing new management practices in highway rights-of-way. 

10.3.2.1 Retrofit existing runoff management facilities 

Many older dry detention basins were designed for the singular purpose of flood control. In some 

cases, a facility of this type can be converted into an extended detention pond/wetland or a 

conventional wet pond. If this retrofit is designed well, it will increase pollutant removal 

capabilities and aquatic habitat functions without losing any of its flood control benefits. This 

modification also typically results in only minimal impacts on the surrounding environment. Dry 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

detention ponds can be modified to accommodate a greater variety of species by transforming 

them into constructed wetlands or installing aquatic platforms, which are shallow benches on 

which aquatic vegetation can be planted (see Section 5.3.1.3 for more information about 

constructed wetlands; Fairfax County Environmental Coordinating Committee, 2002). 

The retrofit process often includes: 

— Analyzing existing hydraulic characteristics and the flood control design specifications of 

the facility; 

— Determining whether there is available storage for water quality treatment; 

— Excavating the pond bottom to create permanent pool storage (for pond and wetland 

systems) if water quality storage is available; 

— Raising the embankment or modifying the outlet structure to obtain additional storage if 

extended detention is needed; 

— Increasing the flow path from inflow point to discharge point by using baffles or earthen 

berms or by regrading the pond’s contours to increase particulate settlement; and 

— Addressing safety considerations, such as fencing and adding underwater benches or 

shallow fringe areas along shorelines, to reduce the risk of drowning. 

Bioengineering to enhance water quality benefits

The City of Griffin, Georgia, constructed a bioengineering system within the North Griffin Regional 

Detention Pond and within a forested wetland area downstream of the pond to improve water quality 

in the receiving waterbody, Flint River. The bioengineering system is comprised of specific species of 

vegetation that provide natural filtration and breakdown of pollutants in runoff. The wetland plants 

selected include cattail, bulrush, pickerel weed, soft rush, wool grass, southern cutgrass, and shallow 

sedge. Experts chose these species based on their anticipated ability to break down and filter various 

pollutants commonly found in runoff. The system has low maintenance requirements and relatively low 

construction and operating costs in comparison to conventional treatment facilities. In addition to water 

quality benefits, the system will enhance wildlife habitat (City of Griffin, no date). The Consulting 

Engineers Council of Georgia recognized the project design and performance success with an 

Engineering Excellence Award in February 2000. The Georgia Environmental Protection Division and 

USEPA Clean Water Act (CWA) Section 319(h) Program also acknowledged the project’s 

achievement (Greuel and Feldner, 2001). A detailed summary of this project is available in EPA’s 

Section 319 Success Stories, Vol. III at http://www.epa.gov/owow/nps/Section319III/GA.htm. 

10.3.2.2 Modify the upstream end of road culverts 

A good retrofit opportunity can sometimes be found at the upstream end of a road culvert. A 

gabion, concrete weir structure, or riser/barrel control structure can be installed to create a small, 

permanent micropool excavated to provide water storage, water quality, and habitat benefits. 

This method can be used to provide a dry extended detention basin with a maximum depth of 6 

feet above the culvert invert. If the upstream area is open floodplain, it might be possible to 

construct a wet pond or extended detention pond/wetland retrofit. 

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Management Measure 10: Existing Development 

Cost-Effectiveness Study of Retrofitting Runoff Treatment Facilities

EPA’s Office of Research and Development investigated retrofitting wet-weather flow treatment 

facilities to determine their feasibility and cost-effectiveness (Moffa et al., 2000). The following retrofit 

scenarios were analyzed: 

— Converting or retrofitting primary settling tanks with dissolved air flotation and lamellae (thin, 

flat membranes or layers) and/or microsand-enhanced plate or tube settling units. 

— Retrofitting existing wet-weather flow storage tanks to provide enhanced settling/treatment 

and post-storm solids removal. 

— Converting dry ponds to wet ponds for enhanced treatment. 

— Retrofitting wet-weather flow storage tanks for dry-weather flow augmentation. 

— Using storage for sanitary sewer overflow control. 

— Retrofitting for industrial wastewater control in a combined sewer system. 

— Bringing outdated/abandoned treatment plants back on-line as wet-weather flow treatment 

facilities. 

The cost-benefit analysis examined site-specific, operational, cost, and design parameters. Each 

retrofit scenario was analyzed over a range of flow and/or volume conditions. The study revealed that 

in certain circumstances, retrofitting existing wet-weather flow treatment facilities is technically feasible 

and can be more cost-effective than construction of new conventional control and treatment facilities. 

The authors concluded that these results were highly site-specific and recommended that retrofitting 

existing control facilities be identified as one of several alternatives to reduce impacts from storm 

events. The full report is available at the Office of Research and Development’s Web site at 

http://www.epa.gov/ednnrmrl/news/main.htm. 

Because roadways are not constructed as runoff management embankments, special measures 

might be necessary to ensure that these facilities meet dam safety specifications for seepage 

control and passage of the 100-year storm. Consideration and evaluation of secondary impacts, 

such as modification of the 100-year floodplain, creation of fish migration barriers, and changes 

to the wetland hydrologic regime is also warranted with this type of retrofit. 

10.3.2.3 Modify storm drainage pipe outfalls 

A volume of runoff can be diverted at or near a storm drainage pipe outfall to a sand filter, peatsand (or other medium) filter, bioretention system, centrifugal deflection system, off-line wetland 

or pond system, or other water quality treatment facility for treatment before it reenters a 

receiving water. 

10.3.2.4 Add retention structures to channelized streams 

Small weir walls or check dams can sometimes be placed in small, previously channelized 

streams to retain sediments and create a ponding area for wetland vegetation. This type of retrofit 

is usually easy to install and can provide moderate pollutant removal benefits. Because it can 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

potentially affect channel design flows and the floodplain, however, careful analysis must be 

conducted before the instream practice is implemented. In addition, cleanout frequency should be 

considered before selecting this practice, as regular maintenance will be needed to remove 

trapped sediments. 

10.3.2.5 Install runoff management practices in or adjacent to large parking areas 

Retrofit practices can be installed near large parking lots to capture, detain, and/or treat runoff. 

Infiltration practices such as bioretention areas, porous pavement, sand filters, and underground 

vaults are good candidates. Two examples of successful use of bioretention areas can be found at 

http://www.epa.gov/owow/nps/bioretention.pdf (USEPA, 2000a). In addition, a case study 

illustrating the effectiveness of porous pavement in reducing runoff is provided at 

http://www.epa.gov/owow/nps/pavements.pdf (USEPA, 2000b). 

10.3.2.6 Construct new practices in highway rights-of-way 

Existing highway systems can have significant open spaces for the installation of various 

practices. For example, cloverleaf open space can be an ideal location for storm water wetlands 

and pond systems if drainage areas and patterns allow. Care must be taken to avoid creating a 

safety hazard for traffic, and maintenance access should be an integral part of the design. 

10.3.2.7 Install trash-capturing devices 

Trash racks are inclined metal grates that trap floatables as water passes through. The racks can 

be installed at storm sewer inlets or outfalls or in the stream itself. These structures effectively 

remove trash from the water, but they require a high level of maintenance (inspection for damage 

or clogging after storms and regular trash removal). If these racks are poorly maintained, their 

effectiveness decreases and they can clog, which can cause a flood hazard. A less-expensive 

alternative to metal trash racks is plastic mesh trash collectors with floating piers that stretch 

across the width of the stream. They are easier to maintain because they are simply removed and 

replaced with a new collector. 

The applicability of these trash collection methods is limited to small streams with relatively low 

flow and low-level trash inputs. More substantial trash collection methods, such as vortex 

devices that use centrifugal force to separate floatables from water, can be installed to handle 

larger flows or high trash loads. 

10.3.2.8 Install inlet and grate inserts 

A wide variety of inserts that trap oil and grease from parking lots, maintenance yards, and 

streets are also commercially available. These can be used with or without trash capture in storm 

drain inlets and grates. Inspection and maintenance one to four times per year (depending on 

pollutant concentrations in runoff) is usually recommended. Catch basin inserts are discussed in 

more detail in Management Measure 5 (section 5.3.5.4). 

10.3.3 Restore and Limit the Destruction of Natural Runoff Conveyance Systems 

Existing development has likely resulted in a modification of natural drainage patterns as 

compared to predevelopment conditions. As a result, increases typically occur in imperviousness, 

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runoff, peak flows during storm events, erosion, and pollutant transport. The use of traditional 

runoff management technology, such as piping, channeling, and curbing, has aggravated these 

impacts. 

Efforts should be made to restore previously developed or redeveloping sites so they more 

closely mimic predevelopment hydrologic conditions. The predevelopment condition should be 

estimated based on historical records and existing slopes, soils, and natural drainage features. 

Consideration should be given to the time of concentration—the time it takes water to travel 

from the farthest point in a subwatershed to the outlet. (Sites might contain multiple 

subwatersheds and multiple outlets.) Paving and curbing substantially reduce time of 

concentration, resulting in high peak flows during storms. Time of concentration can be 

increased substantially by modifying drainage patterns and installing infiltration and detention 

practices. The practices presented in this section can be used to increase time of concentration on 

a particular site. Additional technical guidance for restoration practices can be found at EPA’s 

River Corridor and Wetland Restoration Web site at http://www.epa.gov/owow/wetlands/restore

(USEPA, 2002a). Another resource is Stream Corridor Restoration: Principles, Processes, and 

Practices (FISRWG, 1998), which can be downloaded at 

http://www.nrcs.usda.gov/technical/stream_restoration/newgra.html or ordered by contacting the 

National Technical Information Service, 5285 Port Royal Road, Springfield, VA 22161; 

telephone 703-605-6000 or 800-553-NTIS; e-mail orders@ntis.fedworld.gov. 

10.3.3.1 Disconnect impervious areas 

Roof downspouts can be disconnected from streets and culverts and runoff diverted over 

vegetated areas or infiltration systems (for treatment) or into cisterns or rain barrels (for reuse; 

see Management Measure 5 for more information on these practices). Also, roadway runoff can 

be converted to sheet flow and directed to vegetated buffers, infiltration devices, or other 

pervious areas. 

Rooftop runoff also can be controlled with a vegetated roof cover. These systems consist of a 

high-quality waterproof membrane covered by drainage material, a planting medium, and 

vegetation. Vegetated roof covers use foliage and a lightweight soil mixture to absorb, filter, and 

detain rainfall. The systems are designed to control high-intensity storms by intercepting and 

retaining water until the rainfall peak passes (USEPA, 2000d). Additionally, vegetated roof 

covers improve insulation and reduce the amount of reflected solar radiation, resulting in lower 

temperatures in urban areas. More information about vegetated roof covers can be found at 

http://www.epa.gov/owow/nps/roofcover.pdf. 

The City of Portland, Oregon, encourages residents to reduce the connectivity of impervious 

surfaces through its Downspout Disconnection Program, originally established in 1996 to 

address problems with combined sewer overflows. Through an interagency agreement, the local 

plumbing code was revised to allow downspout disconnection without a permit. The program has 

developed safety standards that establish criteria for the feasibility of a disconnection, as well as 

an inspection and maintenance program to ensure safety. Homeowners can choose to have the 

city disconnect a downspout free of charge, or they can disconnect it themselves and receive a 

cash incentive. Since the start of the program, nearly 17,000 homes have been disconnected and 

data have been collected on an additional 20,000 potential disconnections (Hottenroth, 2003). 

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More information about the Downspout Disconnection Program can be found at 

http://www.portlandonline.com/oni/index.cfm?c=28992. 

10.3.3.2 Encourage overland sheet flow 

Concentrated flow of runoff during storms results in decreased time of concentration, decreased 

infiltration, and increased erosion due to high runoff velocity. Careful regrading to reduce steep 

slopes slows runoff, promotes infiltration, and reduces erosion. (Note that regrading efforts 

should not result in increased compaction; if compaction has occurred, soil amendments and 

rehabilitation may be necessary.) A level spreader, which typically consists of a shallow, gravelfilled trench that receives concentrated flows and converts them to sheet flow, can be installed to 

convey runoff to vegetated areas. A flat, grassy area can also be used to promote overland flow. 

10.3.3.3 Increase flow path 

Increasing the path of runoff results in increased storm water detention and increased travel time. 

Directing concentrated flows from impervious areas to infiltration areas, swales, dry wells, 

cisterns, or bioretention facilities increases the time it takes for runoff to leave the site and 

mitigates peak runoff flows. 

10.3.3.4 Use open swales in place of traditional storm drain systems 

Grassed swales are an effective and natural means of conveying runoff. Because the water comes 

into contact with vegetation, the runoff velocity decreases, which promotes infiltration, reduces 

erosion, and lengthens time of concentration. Because grassed swales are wider and shallower 

than conventional channels, runoff is less concentrated. They are especially appropriate 

alongside roadways or on the border of a site. Swales can be combined with terraces and 

infiltration devices to enhance runoff retention. Swale installation requires a minimum amount of 

excavating and regrading. Vegetation should be established immediately to prevent excessive 

erosion; while vegetation is being established, geotextiles or turf reinforcement mats can be used 

to stabilize exposed soils in the swale. 

One neighborhood in Seattle, Washington, underwent a transformation from conventional to 

natural drainage systems as part of a pilot project, called “SEA Street” (for Street Edge 

Alternatives), conducted by Seattle Public Utilities. Monitoring before and after the installation 

of swales indicated a decline from approximately 5,000 cubic feet of runoff from 8 inches of rain 

to only 132 cubic feet of runoff from 9 inches of rain. The project, which cost approximately 

$800,000, was equivalent to the cost of a conventional curb-and-gutter system and provides 

additional water quality benefits and an anticipated boost to property values (Taus, 2002). More 

information about this project can be found at 

http://www.ci.seattle.wa.us/util/About_SPU/Drainage_&_Sewer_System/Natural_Drainage_Syst

ems/Street_Edge_Alternatives/index.asp. 

10.3.3.5 Establish vegetation throughout the site 

Vegetation intercepts rainfall, decreases runoff velocity by increasing surface roughness, and 

promotes infiltration. Establishing vegetated areas in strategic locations that currently receive 

runoff from impervious areas requires minimal effort, especially when native plant species are 

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Management Measure 10: Existing Development 

used. Excess compaction of these areas by heavy equipment should be avoided. To enhance the 

benefits of vegetated areas, part of a site can be regraded during redevelopment activities to 

direct runoff to these areas. See Management Measure 3: Watershed Protection (section 3.3.3.8) 

for a discussion of urban forestry practices that can help in achieving these goals. 

10.3.3.6 Reestablish ground water recharge 

Traditional development techniques that focus on quickly conveying runoff off-site have resulted 

in decreased infiltration of rainfall to ground water. This ground water deficit results in a lowered 

water table and decreased seepage and baseflow in streams during dry periods. Infiltration 

practices can be installed to promote ground water recharge. Such practices include infiltration 

trenches, infiltration basins, sand filters, biofiltration systems, and vegetated areas underlain by 

permeable soils (see Management Measure 5: New Development Runoff Treatment). 

A Watershed Restoration Plan for the Norwalk River Watershed

Habitat quality and water quality in the Norwalk River watershed of southeastern Connecticut have 

been degraded by erosion, sediment, pesticides, excessive algae growth, driftwood and other 

impoundments, and other types of pollution associated with increased watershed urbanization (NWRI, 

1998). In 1997 federal, state, and local government agencies, environmental groups, and concerned 

citizens formed the Norwalk River Watershed Initiative (NRWI) to halt further degradation and promote 

water quality recovery. Subcommittees were tasked with developing goals for four key issues: 

(1) habitat restoration; (2) land use, flood protection, and open space; (3) water quality; and 

(4) stewardship and education. 

The NWRI assessed existing water quality and riparian conditions based on data collected by the 

Connecticut Department of Environmental Protection, U.S. Geologic Survey, and U.S. Department of 

Agriculture. They also identified land uses that contribute to water quality problems, areas where 

stream channels had been modified by dams or flood control projects, and point sources such as 

municipal wastewater treatment facilities. 

Based on the results of the assessment, the NWRI developed the Norwalk River Watershed Action 

Plan, which describes specific objectives and action items to accomplish those objectives for each of 

the four key areas listed above. Each objective contains a list of specific tasks with the implementing 

group clearly identified, the proposed time line for each task, and a measure of the tasks’ success. 

The NWRI also developed an outreach program to foster stewardship and to educate watershed 

residents about the impacts of daily activities that contribute to the degradation of the Norwalk River 

watershed. 

For more information on the Watershed Action Plan or to obtain a copy of the plan, contact the 

Norwalk River Watershed Coordinator, Connecticut Department of Environmental Protection, Bureau 

of Water Management, 79 Elm Street, Hartford, CT 06106; telephone 860-424-3096; e-mail 

tessa.gutowski@po.state.ct.us. 

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Restoration in the Anacostia River Watershed

The Anacostia River has been cited nationally as exemplifying urban watershed problems (AWRC, 

1998). These problems are typified by 

— Conversion of natural drainage networks into man-made channels. 

— Increased runoff and urban pollutants from impervious surfaces. 

— Channel erosion and associated loss of aquatic habitat from changes in land use. 

— Sediments laden with toxic substances and other pollutants from motor vehicles. 

— Electrical transformers, past applications of persistent pesticides, poorly timed applications of 

fertilizers, combined sewer overflows, atmospheric deposition, and pet waste. 

— Thousands of tons of trash and debris. 

As a result of this degradation, in 1987 a concerted effort to restore and protect the Anacostia 

watershed was initiated in the form of the Anacostia Watershed Restoration Agreement and the 

establishment of the Anacostia Watershed Restoration Committee (AWRC), which involved the 

District of Columbia, Montgomery and Prince George's counties in Maryland, the State of Maryland, 

the U.S. Army Corps of Engineers, the Metropolitan Washington Council of Governments, and the 

Interstate Commission on the Potomac River Basin. The cooperative effort was expanded in 1996 with 

the creation of the AWRC's Anacostia Watershed Citizens Advisory Committee (AWCAC). The 

AWCAC has brought formal recognition of the importance and need for citizen input and involvement 

in the restoration. 

The AWRC established a framework to guide long-term restoration efforts and identified 580 

restoration projects to correct existing environmental problems and enhance overall ecosystem 

quality. As of 1997 approximately $20 million had been spent on implementing roughly 29 percent of 

the 580 identified projects, with additional millions of dollars spent on planning, design, land 

acquisition, and maintenance. An additional $54 million had been spent on engineering controls 

designed to reduce the impacts of combined sewer overflows on the tidal river and of leaking, aging 

sewer lines on tributary streams. As a result of the restoration efforts, the submerged aquatic 

vegetation once absent from the river is beginning to reappear, signaling some improvement in water 

clarity, as the volume and concentrations of pollutants from urban runoff have been reduced. The 

successes have required the identification of problems and associated solutions, coordination of 

programs, and the mobilization of critical government, political, and financial resources. Key features 

in the success of the Anacostia program have been the development of common watershed 

restoration goals and the identification and establishment of partnerships. 

More information about the Anacostia Watershed Restoration Project can be found at 

http://www.anacostia.net/awrc.htm. 

10.3.3.7 Protect sensitive areas 

Areas that should be considered for preservation and restoration at sites with existing 

development include riparian areas, 100-year floodplains, wetlands, woodlands and valuable 

trees, and areas with permeable soils. Steep slopes and erosive soils should be protected and 

stabilized to the extent possible. 

10.3.4 Restore Natural Streams 

Streams degraded by prior urbanization should be restored, if possible, using preexisting 

conditions as a goal or guideline. Eight restoration tools can be applied to help restore urban 

streams. These tools are intended to compensate for stream functions and processes that have 

been diminished or degraded by prior watershed urbanization. Best results are usually obtained 

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Management Measure 10: Existing Development 

when the tools are applied together; otherwise, the same sources that degraded the stream remain 

unchanged, causing similar effects. 

A resource for information about restoring natural streams is Stream Corridor Restoration: 

Principles, Processes, and Practices (FISRWG, 2000), which is available for purchase or 

download at http://www.usda.gov/stream_restoration/newgra.html. Another resource is Urban 

Stream Restoration: A Video Tour of Ecological Restoration Techniques (Riley, 1998b), which is 

available for purchase at http://www.noltemedia.com/nm/urbanstream/index2.html. Finally, the 

Center for Watershed Protection developed 11 manuals, collectively called the Urban 

Subwatershed Restoration Manual Series, that present the information needed to restore small 

urban watersheds in a format that can easily be accessed by watershed groups, municipal staff, 

environmental consultants, and other users. The manuals are available for a fee in hard copy or 

as a download at http://www.cwp.org/USRM_verify.htm. 

10.3.4.1 Partially restore the predevelopment hydrologic regime 

The primary objective of storm water management is to reduce the frequency of bankfull flows 

and other erosive events in the contributing watershed. This is often done by constructing 

upstream storm water retrofit ponds that capture and detain increased storm water runoff for up 

to 24 hours before release (i.e., extended detention). Extended detention systems are often 

designed to control the one-year, 24-hour storm. Storm water retrofit ponds are often critical in 

the restoration of small and mid-sized streams, but they might be less cost-effective in larger 

streams and rivers unless implemented on a watershed basis. 

10.3.4.2 Stabilize channel morphology 

Over time, urban stream channels can become enlarged and are subject to severe bank and bed 

erosion. Therefore, it is important to stabilize the channel and, if possible, restore equilibrium to 

the channel geometry. In addition, it is useful to provide undercuts or overhead tree canopy to 

improve fish habitat. Depending on the stream order, the impervious cover in the watershed, and 

Restoring Channel Morphology in a North Carolina Stream

Long Leaf Creek is located in an urbanized watershed along coastal North Carolina (Sotir, 2000). The 

stream had deepened and widened as a result of increased runoff and severe storms, including 

hurricanes. The changes resulted in reduced aesthetic value, damaged riparian vegetation and 

aquatic and terrestrial habitats, and degraded water quality. Managers selected a soil bioengineering 

approach over other alternatives after considering such issues as erosion control, streambank 

stabilization, safer and healthier environment, flood control, timely project completion, environmental 

and aesthetic improvement, property loss minimization, hydraulic efficiency, and cost feasibility. They 

installed live fascines, brush layer/live fascine combinations, joint planting, and vegetated geogrids. 

The survival rates of the live vegetation ranged from 60 to 80 percent depending on the species used; 

maintenance proved to be a key factor in survival rates. Several important needs were identified, 

including studying bed conditions in areas that have had high deposits of mobile materials, employing 

sophisticated grade control structures, following installation procedures and maintenance schedules, 

and encouraging communication and cooperation between engineers and wetland scientists. 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

the height and angle of eroded banks, a series of different tools can be applied to stabilize the 

channel and prevent further erosion. Bank stabilization measures include revegetated riprap and 

soil bioengineering methods (see Management Measure 7) such as willow stakes, brush bundles, 

bio-logs, lunker structures, and rootwads. 

10.3.4.3 Restore instream habitat structure 

Most urban streams have poor instream habitat structure, often typified by indistinct and shallow 

low-flow channels within a much larger and unstable storm channel. The goal is to restore 

instream habitat structure that has been blown out by erosive floods. Key restoration elements 

include creating pools and riffles, confining and deepening the low-flow channels, and providing 

greater structural complexity across the streambed. Typical tools include installation of log check 

dams, stone wing deflectors, and boulder clusters along the stream channel. 

Urban Stream Restoration in the Waukegan River, Illinois

An urban stream restoration project is underway in the Waukegan River in Illinois to repair channel 

instabilty caused by runoff from impervious surfaces and lack of storm water controls. The project 

uses biotechnical bank restoration to stabilize streambanks and low stone weirs to restore pool and 

riffle sequences. A habitat monitoring design was also used to document water quality changes. The 

project has improved biological diversity through pool and riffle restoration, yet it did not significantly 

improve stream fisheries. For more information about the project, refer to Section 319 Nonpoint 

Source National Monitoring Program: Successes and Recommendations (NCSU, 2000). 

10.3.4.4 Reestablish riparian cover 

Riparian cover is an essential component of the urban stream ecosystem. Riparian cover is 

necessary to stabilize banks, provide large woody debris and detritus, and provide shade to 

maintain water temperatures. Reestablishment of the riparian cover plant community along the 

stream network is often essential to achieve the goals and objectives of the program. This can 

entail active reforestation of native species, removal of exotic species, or changes in mowing 

operations to allow gradual succession. Establishment of an urban stream buffer can achieve 

many of these objectives (see section 3.3.3.6 of Management Measure 3 for a discussion of 

setbacks/stream buffer zones). 

Citizen Involvement in Planting Riparian Forests

In Lexington, Kentucky, a unique program is underway to restore riparian areas to local streams. 

Because the city’s limited budget does not allow for an expensive riparian planting effort, Reforest the 

Bluegrass was established as a cooperative effort by local private and nonprofit organizations, citizen 

groups, and government agencies. Reforest the Bluegrass provides training for citizen volunteers to 

participate in replanting efforts. The program provides public education for participants and for local 

residents through outreach, while significantly reducing program costs. Participants are taught the 

value of riparian systems in protecting water quality, combating the “urban heat island” effect, and 

providing habitat for wildlife. As of April 2002, nearly 4,000 volunteers had planted 108,000 seedlings. 

The program was financed with $85,000 from local government and $50,000 from private donations, 

compared with an estimated cost $675,000 if the project had been completed by contractors (Gabbard 

and Poe, 2003). 

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Management Measure 10: Existing Development 

Restoring Atlanta’s Watersheds 

The International Life Sciences Institute’s Risk Science Institute (RSI) was tasked with assessing the 

condition of streams in Atlanta, Georgia; developing a watershed management implementation plan; 

and identifying specific watershed restoration activities that would improve riparian habitat and water 

quality in four example subwatersheds (RSI, 1998). They identified several habitat and water quality 

impacts that can be attributed to urbanization, including 

— Increased magnitude and frequency of bankfull and subbankfull events. 

— Stream channel dimensions out of equilibrium with hydrologic regime. 

— Enlarged, highly modified channels. 

— Increased sediment load due to upstream channel erosion. 

— Decreased baseflow. 

— Decreased wetted perimeter. 

— Degraded in-stream habitat structure. 

— Reduced large woody debris. 

— Increased number of stream crossings, which are potential barriers to fish migration. 

— Fragmentation and narrowing of riparian forests. 

— Degraded water quality. 

— Increased summer stream temperatures. 

— Reduced aquatic diversity. 

— Combined sewer overflows. 

To address these issues, RSI developed a watershed management program for the Atlanta region 

that includes the following elements: 

— Creation of an institutional framework for watershed management (Management Measure 1). 

— Development of a comprehensive storm and surface water control program. 

— Establishment of erosion and sediment control programs. 

— Establishment of detention pond requirements. 

— Expansion of the tree canopy. 

— Management of buffers, sensitive areas, and floodplains. 

— Establishment of land development provisions. 

— Daylighting of streams. 

— Relocation of utilities. 

— Eradication of invasive and exotic species. 

— Development of a public education and outreach campaign. 

RSI also developed several objectives for the watershed management program and identified 

environmental indicators that can be used to gauge the effectiveness of management activities (see 

Management Measure 2). Finally, RSI examined four subwatersheds to identify specific management 

practices that can be used to fulfill the objectives of the watershed management program. In each 

case study, they identified the activities in the subwatershed that were contributing to resource 

degradation and suggested methods, such as separating storm and sanitary sewers and improving 

storm water infiltration, that would reduce runoff to prevent further waterbody degradation. These 

methods would also increase the effectiveness of in-stream and riparian restoration activities. RSI 

then identified site-specific restoration activities such as streambank stabilization, riparian buffer 

management, and creation or restoration of in-stream habitat. 

For more information about the Watershed Management Program for Atlanta or to receive a copy of 

RSI’s report, contact the Risk Science Institute, International Life Sciences Institute, 1126 16th Street, 

NW, Washington, DC 20036-4810; e-mail rsi@ilsi.org. 

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National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

10.3.4.5 Protect critical stream substrates 

A stable, heterogeneous streambed is often a critical requirement for fish spawning and 

secondary production by aquatic insects. The bed of an urban stream, however, is often highly 

unstable and clogged by deposits of fine sediment. It is often necessary to mechanically restore 

the quality of stream substrates at points along the stream channel. Often, the energy of urban 

storm water can be used to create cleaner substrates through the use of flow concentrators and 

other manufactured devices. (See Management Measure 5 for more information about these 

practices.) If thick deposits of sediment have accumulated on the bed, mechanical sediment 

removal might be needed. 

10.3.4.6 Promote recolonization of the aquatic community 

It may be difficult to reestablish the fish community in an urban stream if downstream fish 

barriers prevent natural recolonization. In these instances it is important to seek the judgment of 

a fishery biologist to determine whether downstream fish barriers exist, whether they can be 

removed, or whether selective stocking of native fish is needed to recolonize the stream reach. 

10.3.4.7 Daylight streams 

Daylighting involves returning a stream that has been buried in a pipe or culvert to the surface. In 

many cases the stream can be restored to its original channel, but sometimes a new channel must 

Daylighting Jolly Giant Creek, Arcata, California

A classic example of daylighting is Arcata, California’s Jolly Giant Creek (Pinkham, 1998). The 

daylighting and stream restoration project was initiated in 1991 by a high school biology teacher, 

Lewis Armin-Hoiland, and Humboldt State University students Melissa Bukosky and Tom Hagberg. 

They initially started the project to provide environmental education to high school and college 

students on stream ecology and restoration, but Bukosky continued to gather data and designed a 

new channel and restoration plan for the creek. 

The Redwood Community Action Agency, a nonprofit regional development organization, obtained a 

grant from the California Department of Water Resources Urban Streams Restoration Program. Other 

funding sources included U.S. Fish and Wildlife Service Challenge Cost-Share, the city of Arcata, and 

donations from a local heavy equipment contractor and the National Tree Trust. A substantial amount 

of volunteer labor was used for revegetation and to conduct assessment and monitoring. Funding for 

the project totaled $120,000. 

The first phase of the stream restoration project included removing nearly 100 feet of culvert; installing 

a sedimentation basin, a 1⁄3-acre pond, and 75 feet of new stream channel; providing bank stabilization 

and flow control measures; and rerouting the stream through an older dry channel with existing 

riparian vegetation. The second phase involved creating a new channel within the old, wider channel 

at an abandoned mill site; creating berms around part of the property; restoring more than 400 feet of 

the Jolly Giant Creek; and providing a seasonal wetland and wet weather detention pond with 

substantial runoff storage capacity. 

For more information contact Richard Pinkham, Senior Research Associate, Rocky Mountain Institute, 

1739 Snowmass Creek Road, Snowmass, CO 81654; telephone 970-927-3807; e-mail 

rpinkham@rmi.org. 

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Management Measure 10: Existing Development 

be engineered. Flow control structures and flood control measures can be incorporated into the 

design of the new or restored channel. Planting, restoring, and maintaining streambank 

vegetation and providing a diversity of instream habitat for submerged aquatic vegetation, fish, 

and aquatic insects are important aspects of the stream restoration project. 

Daylighting typically requires a large capital investment for acquiring permits, engineering 

designs and expertise, equipment and labor for excavation, and plantings and labor to establish 

desirable stream morphology. Because communities are typically in favor of daylighting 

projects, many of these costs can be offset by recruiting sponsors such as property owners, 

community groups, housing associations, municipalities, environmental groups, and contractors. 

The benefits of a daylighting project for a particular stream reach should be carefully considered 

and weighed against the cost to determine whether the project is worthwhile. 

A source of information is Daylighting: New Life for Buried Streams. In addition to summary 

findings, recommendations, and conclusions, the report provides information about completed 

and proposed daylighting projects (Pinkham, 2000). 

10.3.5 Preserve, Enhance, or Establish Buffers 

Stream buffers may be present as part of previous development, but it is unlikely that existing 

buffers were established or maintained to maximize pollutant removal. As the intensity of 

surrounding development increases, runoff and pollutant loads increase and can result in damage 

to the buffer. If the buffer is not protected from disturbance or excessive traffic, it can deteriorate 

over time. Buffers serve several important functions: they help improve soil and water quality, 

stabilize streambanks, decrease flood severity, replenish ground water supply, and provide 

wildlife habitat (Schultz et al., 1996). Some steps that can be taken to preserve or enhance 

existing buffers include: 

— Delineating buffer boundaries and establishing management zones within the buffer 

(streamside, middle, and upland zones); 

— Developing vegetative and use strategies within these zones; 

— Establishing provisions for buffer crossings; 

— Integrating structural runoff management practices where appropriate to protect the 

buffers and to augment their performance; and 

— Developing buffer education and awareness programs. 

A buffer can be established in the area between the stream and existing development when 

buildings are set back from the stream to prevent damage from flooding. These areas can be 

mapped and buffer boundaries established based on runoff and pollutant loadings. In some cases, 

impervious surfaces in the buffer need to be removed or parts of the buffer regraded to ensure 

maximum pollutant removal efficiency. The buffers are then divided into three zones—the 

streamside, middle, and upland zones—that contain different types of vegetation and accomplish 

pollutant removal in different ways (Herson-Jones et al., 1995). Design considerations for stream 

buffers are discussed in more detail in Management Measure 3. 

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10.3.6 Redevelop Urban Areas to Decrease Runoff-Related Impacts 

10.3.6.1 Encourage infill development 

Infill development is a tool planners use to encourage siting of new development on unused 

lands in existing urban areas. Infill development usually works in tandem with community 

redevelopment initiatives to foster revitalization of existing neighborhoods by replacing 

dilapidated buildings and underused properties with new housing or businesses. However, from a 

water quality perspective, if infill development is promoted on unused lands in existing 

developed areas, sites should be selected that result in decreased pollutant loadings and runoff 

volumes. Open space that provides valuable flood control and pollutant removal functions should 

be preserved or enhanced if possible. Trees within existing developments should be protected or 

replanted as necessary. 

Infill and redevelopment can be employed in either large or small projects. One impediment to 

more widespread implementation of infill projects is the existing condition of a potential 

redevelopment site in terms of environmental constraints. The restrictive nature of many land use 

regulations and pressing social and economic issues may also impede implementation. Faced 

with these constraints, local governments often need to modify local zoning or building codes to 

make infill development and redevelopment more inviting to developers. Experience has shown 

that citizen involvement has often been a catalyst for leveraging funding or revising codes for 

this type of renewal. 

10.3.6.2 Assess vacant, abandoned lots and areas of potentially contaminated soils to 

promote redevelopment 

In many urbanized areas, changes in development patterns and economic decline have resulted in 

deterioration or abandonment of industrial and commercial sites. Many of these sites have 

contaminated and compacted soils that discharge polluted runoff during and after storms. These 

underused areas can be identified and assessed to determine if redevelopment or remediation can 

result in significant reductions in pollutant loadings or flow to improve surface water or ground 

water quality. Social and economic benefits may also accrue. Redevelopment plans can include 

the use of practices such as disconnection of impervious areas to reduce the total effective 

impervious area (see section 4.3.2) or infiltration practices including bioretention and onsite 

runoff storage. 

EPA’s Office of Solid Waste and Emergency Response has a brownfields initiative that 

encourages the redevelopment of abandoned, lightly contaminated industrial sites in 

economically stressed communities (USEPA, 1999). The program provides funding and 

guidance to help communities locate potential brownfields redevelopment sites, to perform soil 

and ground water assessments to determine the nature and extent of contamination, and to 

promote environmental clean-up and redevelopment of these sites. The program includes tax 

incentives for potential redevelopers and waivers of liability for past contamination. It 

encourages federal, state, and local coordination of enforcement activities and stakeholder and 

community involvement to identify and plan new uses for brownfields to promote environmental 

health and safety, environmental justice, and economic growth for economically depressed 

communities. 

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Management Measure 10: Existing Development 

The brownfields initiative has several advantages for communities with underused, potentially 

contaminated sites. It provides a catalyst for assessment of urban areas for sites in need of cleanup and redevelopment to improve the community’s surface water and ground water quality, 

quality of life, and property values. Redeveloping properties that have already been disturbed 

helps to prevent development of greenfields—undeveloped suburban areas—and slows the 

growth of imperviousness in the outskirts of urban areas. It also provides an incentive for 

communities to alleviate soil and ground water contamination and to convert abandoned, eyesore 

lands to viable businesses, recreational facilities, or other uses. 

In 2002, the brownfields program was expanded and strengthened through ratification of the 

Small Business Liability Relief and Brownfields Revitalization Act (see 

http://www.epa.gov/brownfields/sblrbra.htm for more information). More information about 

EPA’s Brownfields Initiative is available at http://www.epa.gov/brownfields. 

Chicago Calumet Initiative 

Calumet is located on the southeast side of Chicago along the Calumet River, adjacent to Lake 

Michigan, that has been subject to more than 120 years of heavy industrial activity. Calumet currently 

has thousands of acres of contaminated brownfields located amongst open space that serves as 

habitat for many types of wildlife, including birds listed by the state as endangered or threatened. 

In 2000 Chicago mayor Richard Daley and former Governor George Ryan launched the “Calumet 

Initiative,” a revitalization project that involves brownfields clean-up, the preservation of land and 

wetlands, urban forestry, renewable energy, and low impact development. The City is working in 

partnership with the Illinois Department of Natural Resources, the U.S. Forest Service, EPA, the Fish 

and Wildlife Service, the Illinois Environmental Protection Agency, and 15 other governmental 

partners. 

The Initiative includes plans to redevelop 3,000 acres of brownfields into a region with sustainable 

industries such as a new Ford Motor Company supplier park that uses low impact development 

techniques and minimizes runoff to adjacent waterbodies. The Calumet Tax Increment Financing 

District was established to encourage industries to relocate to the revitalized area. 

The Calumet Open Space Reserve will provide 4,800 acres of rehabilitated and preserved wetlands 

and crucial habitat for the 700 plant and 200 bird species that occupy the land currently. The property 

will be managed through a watershed-based ecological management strategy combined with land 

acquisition and preservation (NALGEP, 2003). 

 10-21 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

10.4 Information Resources 

The Anacostia Watershed Restoration Progress and Conditions Report 1990–1997 summarizes 

accomplishments and ongoing projects of the Anacostia Watershed Resoration Committee as 

they relate to their six restoration goals. In addition, the report provides recommendations to the 

committee for future actions to sustain and further promote the restoration effort. 

The Federal Interagency Stream Restoration Working Group (2000), which is a collaboration 

among of 15 federal agencies including EPA and USDA, published Stream Corridor 

Restoration: Principles, Processes, and Practices. This document covers background 

information about stream corridors, including processes, characteristics, and disturbances; 

development of a stream corridor restoration plan; and application of restoration principles to 

stream corridor projects. Stream Corridor Restoration: Principles, Processes, and Practices can 

be purchased or downloaded in PDF format at 

http://www.nrcs.usda.gov/technical/stream_restoration/newgra.html. 

Riparian Buffer Strategies for Urban Watersheds (Herson-Jones et al., 1995) provides guidance 

on riparian buffer programs used to mitigate the impact of urban areas on nearby streams. The 

document uses the results of a national survey of riparian buffer programs as well as a 

comprehensive review of riparian buffer literature to make recommendations on buffer design. It 

also analyzes buffer pollutant removal potential and pollution prevention techniques via 

chemical, biological, and physical processes. It is available for purchase at 

http://www.mwcog.org/ic/95703.html. 

The Save Our Streams Program is a national watershed education and outreach program by the 

Izaak Walton League (no date). The league offers many stream-related resources, including 

information on stream projects and publications such as A Citizen’s Streambank Restoration 

Handbook. The Save Our Streams Program can be reached by e-mail at sos@iwla.org, by calling 

1-800-BUG-IWLA, or by visiting the Web site at http://www.iwla.org/sos. 

The Natural Resources Conservation Service’s National Conservation Buffer Initiative Web site 

(http://www.nrcs.usda.gov/feature/buffers/) contains information about buffers, links to 

technology information, and buffer initiative contacts (NRCS, no date). 

Urban Restoration: A Video Tour of Ecological Restoration Techniques (Riley, 1998b) is a video 

tour of six urban stream restoration sites. It includes background information on how the projects 

were funded and organized with community involvement and the history and principles of 

restoration. Additionally, examples are presented of stream restoration in very urbanized areas, 

recreating stream shapes and meanders, creek daylighting, soil bioengineering, and ecological 

flood control projects. A companion to the video is Restoring Streams in Cities: A Guide for 

Planners, Policymakers, and Citizens (Riley, 1998a). This book includes detailed information on 

all relevant components of stream restoration projects, from historical background to hands-on 

techniques. The book and video can be purchased at 

http://www.noltemedia.com/nm/urbanstream/index2.html. 

EPA and the LID Center conducted a literature review of LID studies to assess the state of 

knowledge about LID practices (USEPA, 2000c). The final report contains a brief overview of 

LID principles and programmatic issues such as use, ownership, and cost. The heart of the 

10-22 
Management Measure 10: Existing Development 

document is a summary of the information available regarding the pollutant removal 

effectiveness of the most common LID practices. The report is available for download in PDF 

format at http://www.epa.gov/owow/nps/lidlit.html. This page also contains links to low-impact 

development fact sheets on bioretention, vegetated roof covers, permeable pavements, and street 

surface storage of runoff. 

EPA’s River Corridor and Wetland Restoration Web site contains general information about 

restoration and its benefits, a list of restoration guiding principles that cover the entire life of a 

restoration project from early planning to postimplementation monitoring, restoration project 

descriptions, and links to other restoration resources. The site is located at 

http://www.epa.gov/owow/wetlands/restore. 

The Center for Watershed Protection developed 11 manuals, called the Urban Subwatershed 

Restoration Manual Series, that present the information needed to restore small urban watersheds 

in a format that can easily be accessed by watershed groups, municipal staff, environmental 

consultants, and other users. The manuals are available for a fee in hard copy or as a download at 

http://www.cwp.org/USRM_verify.htm. 

 10-23 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

10.5 References 

Anacostia Watershed Restoration Committee (AWRC). 1998. Anacostia Watershed Restoration 

Progress and Conditions Report 1990–1997. Prepared for the Anacostia Watershed 

Restoration Committee, Washington, DC, by the Metropolitan Washington Council of 

Governments, Washington, DC. 

Center for Watershed Protection (CWP). 1995a. Assessing the potential for urban watershed 

restoration. Watershed Protection Techniques 1(4):166–172. 

Center for Watershed Protection (CWP). 1995b. Stormwater retrofits—a tool for watershed 

enhancement. Watershed Protection Techniques 1(4):188–191. 

City of Griffin. No date. City of Griffin Stormwater Department: Projects. 

http://www.griffinstorm.com/SW/Projects.htm. August 1, 2003. 

Dahme, Joanne. 2003. Clean Water – Green City. Presented at the World Water and 

Environmental Resources Congress, Philadelphia, PA, June 2003. 

Fairfax County Environmental Coordinating Committee. 2002. Preliminary Draft: Regional 

Pond as a Watershed Management Tool. Prepared by the Regional Pond Subcommittee. 

http://www.co.fairfax.va.us/gov/DPWES/publications/RPC_Prelimary_Report_Draft_10

_21.pdf. Accessed June 25, 2003. 

Federal Interagency Stream Restoration Working Group (FISRWG). 1998. Stream Corridor 

Restoration: Principles, Processes, and Practices. PB98-158348LUW. Federal 

Interagency Stream Restoration Working Group, Washington, DC. 

Gabbard, H.D. and A. Poe. 2003. Reforest the Bluegrass: Empowerment of the Citizen 

Watershed Manager. In Proceedings, National Conference on Urban Stormwater: 

Enhancing Programs at the Local Level, February 17–20, 2003, Chicago, IL. 

Gruel, R.A. and R.A. Feldner. North Griffin Regional Detention Pond: Wetlands Filtration and 

Treatment for Nonpoint-Source Pollution Control and Abatement: A well-planned system 

prevents flooding and removes pollutants. Stormwater 2(4). 

Herson-Jones, L.M., M. Heraty, and B. Jordan. 1995. Environmental Land Planning Series: 

Riparian Buffer Strategies for Urban Watersheds. Metropolitan Washington Council of 

Governments, Washington, DC. 

 Hottenroth, D.C. 2003. Using Incentives and Other Actions to Reduce Watershed Impacts from 

Existing Development. In Proceedings, National Conference on Urban Stormwater: 

Enhancing Programs at the Local Level, February 17–20, 2003, Chicago, IL. 

Izaak Walton League. No date. Welcome to the Save Our Streams Program. 

http://www.iwla.org/sos. Accessed April 25, 2002. 

10-24 
Management Measure 10: Existing Development 

Moffa, P.E., H.M. Goebel, D.P. Davis, and J.J. La Gorga. 2000. Retrofitting Control Facilities 

for Wet-Weather Flow Treatment: Research Report. EPA-600-R-00-020. Prepared for 

U.S. Environmental Protection Agency, Office of Research and Development, 

Washington, DC, by Moffa & Associates Consulting Engineers, Syracuse, NY. 

Murante, R.U. 2003. Storm Water Management in the City of Chicago. In Proceedings, National 

Conference on Urban Stormwater: Enhancing Programs at the Local Level, February 17–

20, 2003, Chicago, IL. 

National Association of Local Government Environmental Professionals (NALGEP). 2003. 

Smart Growth for Clean Water: Helping Communities Address the Water Quality 

Impacts of Sprawl. National Association of Local Government Environmental 

Professionals, Trust for Public Land, ERG. 

http://www.resourcesaver.com/file/toolmanager/CustomO93C337F42157.pdf. Accessed 

June 30, 2003. 

Natural Resources Conservation Service (NRCS). No date. Buffer Strips: Common Sense 

Conservation. http://www.nrcs.usda.gov/feature/buffers/. Accessed April 25, 2002. 

North Carolina State University (NCSU). 2000. Section 319 Nonpoint Source National 

Monitoring Program: Successes and Recommendations. Preprint. North Carolina State 

University Water Quality Group, Raleigh, NC. 

Norwalk River Watershed Initiative Committee (NWRI). 1998. The Norwalk River Watershed 

Action Plan. http://www.norwalkriverwatershed.org/action.html. Accessed April 30, 

2001. 

O’Leary, M.J. 2003. Conservation Plan for Three Watersheds with the Milwaukee Metro 

Sewerage District. In Proceedings, National Conference on Urban Stormwater: 

Enhancing Programs at the Local Level, February 17–20, 2003, Chicago, IL. 

Pinkham, R. 1998. Buried urban streams see the light. Nonpoint Source News-Notes 53. Terrene 

Institute, Alexandria, VA. 

Pinkham, R. 2000. Daylighting: New Life for Buried Streams. Rocky Mountain Institute, 

Snowmass, CO. 

Prince George’s County, Maryland, Department of Environmental Resources. 2000. Low-Impact 

Development Design Strategies: An Integrated Design Approach. Prince George’s 

County, Maryland, Department of Environmental Resources, Programs and Planning 

Division, Largo, MD. 

Riley, A. 1998a. Restoring Streams in Cities: A Guide for Planners, Policymakers, and Citizens. 

Island Press, Washington, DC. 

Riley, A. 1998b. Urban Restoration: A Video Tour of Ecological Restoration Techniques. 

Noltemedia, Santa Rosa, CA. 

 10-25 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Risk Science Institute (RSI). 1998. Mitigation of Urban Runoff Impacts on Atlanta Streams. Risk 

Science Institute Expert Working Group on Watershed Management in Atlanta, 

International Life Sciences Institute, Washington, DC. 

Schueler, T. 1995. Environmental Land Planning Series: Site Planning for Urban Stream 

Protection. Metropolitan Washington Council of Governments, Washington, DC. 

Schultz, R.C., A. Kuehl, J.P. Colletti, P. Wray, and T. Isenhart. 1996. Stewards of Our Streams: 

Riparian Buffer Systems. Iowa State University, University Extension, Ames, IA. 

Sotir, R.B. 2000. Getting Past the Obvious. Pages 83–93 in National Conference on Tools for 

Urban Water Resource Management and Protection. U.S. Environmental Protection 

Agency, Office of Research and Development, Chicago, Illinois, February 7–10, 2000. 

EPA-625-R-00-001. 

Taus, Margaret. 2002. Innovative Design Cuts Street Runoff. Seattle Post-Intelligence. 

November 20, 2002. http://seattlepi.nwsource.com/local/95881_model20.shtml. Accessed 

June 23, 2003. 

U.S. Environmental Protection Agency (USEPA). 1999. Brownfields. 

http://www.epa.gov/brownfields. Last updated October 5, 1999. Accessed 

October 20, 1999. 

U.S. Environmental Protection Agency (USEPA). 2000a. Bioretention Applications. 

http://www.epa.gov/owow/nps/bioretention.pdf. Last updated October 2000. Accessed 

April 30, 2001. 

U.S. Environmental Protection Agency (USEPA). 2000b. Field Evaluation of Permeable 

Pavements for Stormwater Management. http://www.epa.gov/owow/nps/pavements.pdf. 

Last updated October 2000. Accessed April 30, 2001. 

U.S. Environmental Protection Agency (USEPA). 2000c. Low Impact Development Literature 

Review. EPA-841-B-00-005. U.S. Environmental Protection Agency, Office of Water, 

Washington, DC. 

U.S. Environmental Protection Agency (USEPA). 2000d. Vegetated Roof Cover. EPA-841-B-00-

005D. http://www.epa.gov/owow/nps/roofcover.pdf. Last updated October 2000. 

Accessed March 29, 2001. 

U.S. Environmental Protection Agency (USEPA). 2002a. River Corridor and Wetland 

Restoration. http://www.epa.gov/owow/wetlands/restore. Last updated February 14, 

2002. Accessed April 25, 2002. 

U.S. Environmental Protection Agency (USEPA). 2002b. Small Business Liability Relief and 

Brownfields Revitalization Act. http://www.epa.gov/brownfields/sblrbra.htm. Last 

updated May 3, 2002. Accessed May 17, 2002. 

10-26 
Management Measure 10: Existing Development 

Wilson, A., J.L. Uncapher, L. McManigal, L.H. Lovins, M. Cureton, and W.D. Browning. 1998. 

Green Development: Integrating Ecology and Real Estate. John Wiley & Sons, Inc., New 

York, NY. 

 10-27 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

10-28 
Management Measure 11: Operation and Maintenance 

MANAGEMENT MEASURE 11 

OPERATION AND MAINTENANCE 

11.1 Management Measure 

Develop a program for regular inspection and maintenance of urban runoff management 

practices. 

— Develop and implement an operation and maintenance plan for urban runoff management 

practices. The plan should include scheduled inspections, scheduled maintenance activities, 

and scheduled evaluations of operation and maintenance practices. 

— Inspect, maintain, and repair runoff treatment controls to maintain design treatment capacity. 

— Inspect, maintain, and restore riparian buffers. 

11.2 Management Measure Description and Selection 

11.2.1 Description 

The maintenance of storm water controls is essential to ensure that overall program goals are met 

and that each management practice or set of practices continues to function as designed. Storm 

water controls need to be periodically inspected and maintained as necessary to fine-tune 

performance, prevent malfunction, and address any problems that may arise. Although 

maintenance issues should be a major consideration during the management practice selection 

process, they are often overlooked and inadequately planned for and budgeted. As a result, many 

management practices fail to perform as intended. 

An operation and maintenance (O&M) plan is one way to systematically ensure that scheduled 

inspections, maintenance, and practice evaluations occur. Formalizing an operation and 

maintenance plan also can be helpful in determining and securing the funding necessary to 

properly operate and maintain runoff management practices. 

Program managers should consider incorporating the following elements in their operation and 

maintenance programs: 

− Scheduled inspections (based on climate, precipitation, and runoff management practice); 

− Scheduled maintenance activities, such as removal of forebay sediment; 

− Use of maintenance checklists to systematize and document the inspection process; and 

− Initial and follow-up monitoring of management practices to establish performance 

baselines and trends to guide maintenance activities. 

 11-1 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Maintenance activities may vary by management practice. For example, vegetation management 

is necessary for some extended detention wet ponds and constructed wetlands to maintain 

optimal removal efficiency, to avoid the net export of nutrients during winter, and to maintain 

design flow patterns. Removal of sediment build-up is essential to maintain properly functioning 

practices. Infiltration devices must be protected and maintained to prevent pore clogging and loss 

of infiltration capacity. 

Preventative maintenance may also be necessary to protect the performance of management 

practices. Run-on sedimentation from off-site areas may need to be addressed through 

stabilization measures to prevent unnecessary maintenance expenditures. 

The incorporation of maintenance considerations into management practice designs will often 

reduce subsequent maintenance costs and repairs and help to avoid failures. For example, the 

removal of material from sediment traps can be facilitated by designs that allow easy access to 

accumulated sediments without specialized equipment. Safe and convenient access to inlet and 

outlet structures can reduce maintenance costs and prevent nuisance flooding. Finally, the use of 

proper construction techniques and phasing can reduce the potential for initial clogging of 

infiltration devices during the construction process. 

Enforcement of inspection and maintenance programs is crucial to their success. A 1992 study in 

Maryland evaluated 250 storm water practices to determine whether they were being maintained 

in compliance with the state’s Stormwater Management Act. The researchers found that after a 

few years, approximately one-third of the practices were not functioning as designed, and most 

required maintenance. Approximately one-half of the facilities were undergoing sedimentation 

and many had problems with clogging (Lindsey et al., 1992). Implementing the practices 

described under this management measure can help develop an effective O&M program for 

continued effectiveness and longevity of runoff management practices. 

11.2.2 Management Measure Selection 

This management measure was selected because improper operation and maintenance of runoff 

control practices can result in poor performance and increased discharge of pollutants to 

downstream waters. Flooding may occur and downstream channel stability could be jeopardized. 

Poorly maintained runoff systems also may increase risks to public safety and the potential for 

property damage. 

To prevent these potential impacts, effective maintenance programs should include standards for 

the inspection and maintenance of runoff controls. The entities responsible for maintaining 

runoff controls must be clearly identified and adequate resources must be provided to conduct 

the necessary maintenance activities. Because maintenance issues are critical to successful 

program implementation, they should be planned for at the outset of the runoff management 

program and conducted continuously for the lifespan of the practice(s). 

The following section contains descriptions of specific O&M requirements for various types of 

management practices. 

11-2 
Management Measure 11: Operation and Maintenance 

11.3 Management Practices 

11.3.1 Establishing an Operation and Maintenance Program 

The following section outlines several practices that will facilitate development of a runoff 

control O&M program. 

11.3.1.1 Establish a runoff control operation and maintenance ordinance 

One way for local governments to ensure that maintenance of runoff control facilities is 

performed is to establish an ordinance that mandates these activities. The O&M language in a 

runoff control ordinance can specify that runoff management practices must be designed to 

facilitate easy maintenance and require that regular maintenance activities be performed. 

EPA (2000) has provided model ordinance language (at http://www.epa.gov/nps/ordinance) that 

includes consideration of maintaining runoff control management practices. Ordinance language 

examples from across the country are provided, including a sample maintenance agreement, a 

sample easement and right-of-way agreement, an inspection checklist, and a performance bond. 

It is important for O&M ordinances to contain language that requires the identification of the 

specific entity or entities responsible for long-term maintenance and requires regular inspection 

visits. The ordinance also should provide design guidelines that can help ease the maintenance 

burden, such as the inclusion of maintenance easements. Note that runoff control ordinance 

language regarding the maintenance of erosion and sediment control practices differs from that 

regarding maintenance of postconstruction controls because of the short-term nature of the 

former. 

The City of Alexandria, Virginia has incorporated inspection and maintenance requirements into 

the Alexandria Zoning Ordinance. The ordinance requires the submission of a long-term 

inspection and maintenance plan that identifies all maintenance requirements and responsible 

parties. A standard maintenance and monitoring agreement approved by the city council is 

required for urban runoff practices in Alexandria and cannot be modified without council 

approval (Bell, 1997). 

11.3.1.2 Make provisions for maintenance in the design and construction of management 

practices 

Because maintenance programs play such an important role in ensuring the proper operation of 

most structural practices and some source controls, emphasis should be given to maintenance 

issues when identifying management practices under any runoff management program. Making 

provisions for maintenance at the design and construction phase involves identifying the urban 

runoff practices to be used when designing a new facility. Practices should be designed so that 

maintenance equipment (mowers and vacuum trucks) can easily access the site. Many practices 

have been designed with inadequate pre-treatment (i.e., without a sediment basin at the inlet), 

and they have not performed as anticipated. Inlet and outlet structures also tend to clog easily 

without proper design and maintenance. Adequate size and storage volume based on expected 

sediment loads from the contributing drainage area should be factored into the design of inlets 

and pre-treatment structures. 

 11-3 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

11.3.1.3 Identify mechanisms for program funding 

It is important to identify the entity responsible for operating and maintaining structural runoff 

control practices. The responsible party can be a property owner, homeowners’ association, 

certified contractor, or local government agency. Local governments may assume the 

responsibility of maintaining privately owned facilities. When private entities do not fulfill their 

maintenance responsibilities and the facilities fail, the burden of maintaining runoff control and 

performing downstream restoration may ultimately fall under the local government’s 

responsibility. Public financing for maintenance of both public and private facilities can be 

generated from general tax revenues, storm water utility fees, inspection or permit fees, or 

dedicated contributions. Sources of funding should be dedicated to runoff program budgets and 

or maintenance programs whenever possible. A discussion of these and other financing options 

for maintenance of runoff control facilities is provided in Chapter 8 of the Watershed 

Management Institute’s Operation, Maintenance, and Management of Stormwater Management 

Systems (1997). 

It is important that the funding source for maintenance of runoff control facilities be supported 

by the public. The Watershed Management Institute (1997) stresses the importance of public 

education to inform citizens about the locations and functions of runoff control facilities and the 

importance of regular maintenance. The institute believes that citizens and government officials 

will be more willing to allocate funds to projects that they know will provide tangible benefits to 

the community. The institute also recommends that funding programs for maintenance activities 

have the following attributes: 

— Be based on a stable source of consistent funds that will ensure a long-term commitment 

of personnel, equipment, and materials; 

— Be compatible with the local organizational structure to allow use of existing billing, 

collection, and bookkeeping operations; 

— Include provisions for four essential operations: (1) program administration; (2) 

accounting and budgeting; (3) revenue management; and (4) information management; 

— Be based on an equitable, understandable, and defensible fee or rate structure; 

— Be continually reviewed and updated to meet the changing maintenance needs of the 

runoff control program; and 

— Be consistent with applicable state laws and regulations. 

11.3.1.4 Plan regular inspections 

Inspections are essential to maintain the successful operation of the facility. Inspectors should 

have on hand equipment necessary for taking measurements and making minor repairs, be 

trained in identifying and remedying problems, and have a set of standard inspection procedures 

from which to work. An inspection schedule and checklist for each type of management practice 

should be developed and followed. Inspections and maintenance should be conducted both on a 

regular schedule and following storms to identify and repair any damage. 

11-4 
Management Measure 11: Operation and Maintenance 

11.3.1.5 Schedule maintenance, cleaning, and debris removal to avoid sediment 

accumulation 

Sediment and debris can contain hazardous contaminants and can clog filtration and infiltration 

practices, reducing their effectiveness over time. In addition to major structural controls, 

maintenance programs should include measures for cleaning catch basins and drainage channels. 

Establishment of an effective O&M program should include the creation of maintenance logs 

and identification of specific maintenance triggers for each class of control (e.g., removing 

sediment from forebays every year and retention ponds every five years, cleaning catch basins at 

least annually prior to the rainy season, removing litter from channels twice a year). If 

maintenance activities are scheduled infrequently, regular inspections should be made to ensure 

that the control is operating adequately. Additionally, maintenance should be performed 

following significant storms. 

11.3.1.6 Make provisions for monitoring treatment criteria 

Regularly monitoring the influent to and effluent from structural management practices will 

support program goals by facilitating development of a database to track the effectiveness of 

these practices, which can help guide future decisions about management practice 

implementation. These data will make it easier to quantify the performance of the practice and 

determine the behavior of the system as a result of regular maintenance. 

11.3.1.7 Implement training and certification programs to provide educational 

opportunities for management practice operators 

Training and certification programs are gaining popularity around the country at both the state 

and local levels. Municipalities sometimes use contractors to conduct inspections and 

maintenance because resources are not available to purchase equipment and hire dedicated staff. 

Good training programs can ensure that inspections and maintenance activities are carried out in 

a thorough and consistent manner. Also, training programs can be customized to address local 

concerns and conditions such as high flows, highly erodible soils, or invasive species. 

11.3.1.8 Disposal of residuals 

Runoff can carry both natural and anthropogenic pollutants and materials to receiving waters. 

Natural materials, such as leaves and soils, can accumulate in the system and cause localized 

flooding. Anthropogenic sources, which include oil and grease, heavy metals, deicing materials, 

and litter, can become adsorbed to leaf litter and sediments (Lenhart and Harbaugh, 2000). The 

mixed composition of solids that are removed from the storm drain system (termed residuals) can 

require special handling and treatment, which increases disposal costs (Field and O’Shea, 1994). 

The characteristics of residuals tend to vary with season and land use. Table 11.1 summarizes the 

results of a number of studies analyzing residuals in runoff (Field and O’Shea, 1992; Marquette 

University, 1982; Schueler and Yousef, 1994). 

 11-5 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Table 11.1: Properties of urban storm water solids/residuals (adapted from USEPA, 1999). 

Properties of 

Residuals Wet Ponds1

Sediment 

Basin2

Swirl and 

Helical Bend 

Solids 

Separators3

In-Line 

Upsized Storm 

Conduit4

Urban Storm 

Water Runoff 

Residuals5

Solids 

Volatile 

Suspended 

Solids 

6% 104–155 mg/l 107,310 mg/l 25,800 mg/l 90 mg/l 

Total 

Suspended 

Solids 

43% 233–793 mg/l 344–1,140 mg/l 161,000 mg/l 415 mg/l 

Nutrients 

Phosphorus 583 mg/kg < 5 mg/l <5 mg/l 0.3–2,250 mg/l 502–1,270 mg/kg 

Total 

Kjeldahl 

Nitrogen 

2,931 mg/kg <5 mg/l <5 mg/l 0.3–2,250 mg/l 1,140–3,370 mg/kg 

Heavy Metals 

Zinc 6–3,171 mg/kg 302–352 mg/kg 

Lead 11–748 mg/kg 251–294 mg/kg 

Chromium 4.8–120 mg/kg 168–458 mg/kg 

Nickel 3–52 mg/kg 69–143 mg/kg 

Copper 2–173 mg/kg 251–294 mg/kg 

Cadmium No detect–15 mg/kg 

Iron 6.1–2,970 mg/l 6.1–2,970 mg/l 6.1–2,970 mg/l 

Hydrocarbons 2,087-12,892 mg/kg 1

 Scheuler and Yousef, 1994 

2

 Marquette University, 1982 (Racine, Wisconsin) 

3

 Marquette University, 1982 (Boston, Massachusetts) 

4 Marquette University, 1982 (Lansing, Michigan) 

5

 Field and O’Shea, 1992

A system for managing residuals in runoff should address the proper handling and disposal of 

both liquid and solid residuals. Ponds, infiltration practices, vegetative controls, and catch basin 

inserts have different removal mechanisms, and the type of residuals generated from these 

practices will vary. All residuals should be tested for contamination (unless the management 

entity has determined that residuals from an individual practice or category of practices pose no 

hazard), and maintenance employees should be trained in properly identifying and handling 

contaminated waste according to the requirements of the Resource Conservation and Recovery 

Act (RCRA) and state and local regulations (USEPA, 1999). Removal mechanisms and 

requirements for specific practices are described below. 

Non-hazardous solids in residuals can be recycled, sent to a landfill, or applied to land. Land 

application involves spreading the material on designated land at approved application rates. The 

material should not be applied to cropland, but application to a nonagricultural vegetated area 

may be appropriate (USEPA, 1999). Disposal of the waste in a landfill may be the most 

expensive option because of travel costs, testing requirements, and disposal fees (Lenhart and 

Harbaugh, 2000). 

11-6 
Management Measure 11: Operation and Maintenance 

There are a number of low-cost options for recycling. Coarse sand and gravel can be used for 

road base, and road sand can be recycled for winter maintenance activities. The City of Olympia, 

Washington uses dried solids from treatment systems by mixing them with cement. The organic 

portion of residuals can be composted after removing the coarse inorganic materials. These 

organic residuals can then be combined with yard debris, leaves, straw, or soil. The Washington 

Department of Transportation mixes solids with mulch and bark for use as topsoil along 

roadsides (Lenhart and Harbaugh, 2000). In general, urban runoff residuals have very low 

nutrient content and thus require mixing with high nutrient content organic matter to provide 

fertilization benefits (Field and O’Shea, 1994). 

Additional considerations for the disposal of residuals include air and noise pollution from 

machinery operation at the disposal site, unpleasant odors, possible ground water or surface 

water contamination, and public health. To address these issues, local and state agencies should 

address the following when developing guidelines for disposal of residuals: application rates, 

treatment requirements, site suitability, and proximity to schools, parks, and residential areas 

(Field and O’Shea, 1994). 

The City of Everett, Washington uses a source separation system that requires operators of 

vacuum trucks to determine whether contamination of residuals is suspected based on sheen, 

odor, and color. Residuals suspected of contamination are handled in accordance with state and 

local regulations. Otherwise, materials are collected and recycled as aggregate material on 

medians and selected roadsides after being tested for contamination (Lenhart and Harbaugh, 

2000). 

11.3.2 Source Control Operation and Maintenance 

11.3.2.1 Infrastructure 

(1) Street sweeping. Street cleaning reduces pollutants carried in runoff from street surfaces. The 

frequency of cleanings should reflect the rate of pollutant buildup and should increase just 

before the rainy season. An effective program requires that street sweeping be conducted on 

a regular basis. Sweeper operators require training, and equipment needs to be maintained 

regularly to ensure that it is functioning as designed. Finally, parking restrictions can be 

implemented to guarantee adequate cleaning despite on-street parking. Table 11.2 shows 

O&M costs associated with street sweeping. See Management Measure 7 for more 

information about types of street sweepers (brush vs. vacuum sweepers and their relative 

effectiveness, section 7.3.5.1) and roadside trash removal (section 7.3.5.4). 

 11-7 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Table 11.2: Street sweeper O&M costs (adapted from CWP, 1998). 

Sweeper Type

Maintenance Considerations Mechanical Sweeper Vacuum-Assisted Sweeper

Cost ($/curb mile) 30 15 

Weekly sweeping ($) 1,680 946 

Biweekly sweeping ($) 840 473 

Monthly sweeping ($) 388 218 

4 times per year sweeping ($) 129 73 

Twice per year sweeping ($) 65 36 

O&M costs 

(1998 dollars) 

Annual sweeping ($) 32 18 

Expected life (years) 5 8 

(2) Storm drain flushing. This practice is used to remove deposited materials from storm drain 

pipes to maintain their flow capacity. The flushing schedule should be designed to prevent 

excessive buildup based on estimated inputs from the contributing drainage areas, cleaning 

history, and visual inspections. Flushing is performed either at or upstream from problem 

areas. There are costs to consider for collecting and disposing of sediments, debris, and flush 

water, in addition to supplying flush water and treating sediment-laden water if the storm 

drains are being flushed to a receiving water body. 

(3) Catch basin cleaning. Cleaning catch basins removes excess pollutants, thereby reducing 

high pollutant concentrations in a storm’s first flush, preventing clogging, and restoring 

sediment-trapping capacity. Maintenance should target areas with the greatest pollutant 

loading and those near sensitive water bodies. A maintenance log should be kept to track 

progress. If there are many catch basins in a community, mechanical cleaners (vacuums or 

bucket loaders) may be required; otherwise, hand cleaning will suffice. Proper recordkeeping, waste disposal, and safety procedures are essential for a successful program. 

(4) Highway, bridge, and road maintenance. Maintenance of roads and bridges can be a 

significant source of pollutants. Some methods to prevent materials from contaminating 

runoff are limiting the use of salts; using suspended tarps, vacuums, or booms to reduce 

pollutant drift onto waters from scraping and painting; and training road crews in proper 

waste control and disposal methods. Treatment controls also can be used on-site to reduce the 

amount of polluted runoff that enters receiving waters. Runoff reduction, conveyance, and 

treatment practices (e.g., infiltration swales in median strips) can be incorporated into the 

design of new roadways and bridges to help contain pollutants from traffic as well as from 

Sediment Removal from Catch Basins

The Delaware County, New York, Department of Public Works, with the assistance of the Catskill 

Watershed Corporation, purchased a vacuum truck capable of removing sediment from culverts and 

catch basins. The truck, which has a 30-foot pipe reach and a 12 cubic yard storage capacity, is 

available for use by neighboring counties based on need and availability. In the first month of 

operations, approximately 700 cubic feet of sediment was removed. The sediment s disposed of 

without posing a threat of contamination to the Cannonsville and Pepacton reservoirs. The County will 

be sampling sediment in an attempt to quantify the amount of contaminants removed (Delaware 

County Departments of Planning and Public Works, 2003). 

11-8 
Management Measure 11: Operation and Maintenance 

maintenance activities. For more information about runoff management practices for roads, 

highways, and bridges, see Management Measure 7: Bridges and Highways. 

11.3.2.2 Trash in channels and creeks 

Clean-up of trash from streams and storm water conveyance infrastructure can reduce pollutant 

levels in downstream waters. Areas where dumping occurs frequently can be identified and 

inspected regularly, and “no littering” or “no dumping” signs can be posted to deter future 

dumping. Steep fines for dumping may also discourage potential transgressors. Associated costs 

for these practices are the purchase of signs and equipment, paying personnel to conduct 

inspections and clean-up, and providing landfill space to dispose of recovered items. Cost 

savings can be achieved through community or volunteer clean-up programs. 

11.3.3 Treatment Control Operation and Maintenance 

Runoff treatment controls require periodic inspection and maintenance to ensure that sediment, 

trash, and overgrown vegetation are not impeding their performance. Regular inspections should 

be performed along with routine maintenance. Nonroutine maintenance may be required to repair 

structures, control erosion, and remove unwanted vegetation. Table 11.3 and the following 

practices describe maintenance costs, activities, and schedules for several categories of urban 

runoff treatment practices. 

Table 11.3: Maintenance costs, activities, and schedules for runoff control practices in 1998 

dollars (Adapted from CWP, 1998).

Category 

Management 

Practice 

Annual 

Maintenance 

Cost (% of 

Construction 

Cost) 

Maintenance 

Cost for a 

“Typical” 

Application Maintenance Activity Schedule 

— Cleaning and removal of 

debris after major storms 

(>2” rainfall) 

— Harvesting of vegetation 

when a 50% reduction in 

the original open water 

surface area occurs 

— Repair of embankment 

and side slopes 

— Repair of control 

structure 

Annual or as 

needed 

— Removal of accumulated 

sediment from forebays 

or sediment storage areas 

when 60% of the original 

volume has been lost 

5-year cycle 

Detention 

ponds or 

vaults 

Dry ponds ~1% $1,200 

— Removal of accumulated 

sediment from main cells 

of pond once 50% of the 

original volume has been 

lost 

20-year 

cycle 

 11-9 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Table 11.3 (continued).

Category 

Management 

Practice 

Annual 

Maintenance 

Cost (% of 

Construction 

Cost) 

Maintenance 

Cost for a 

“Typical” 

Application Maintenance Activity Schedule 

— Cleaning and removal of 

debris after major storm 

events (>2” rainfall) 

— Harvesting of vegetation 

when a 50% reduction in 

the original open water 

surface area occurs 

— Repair of embankment 

and side slopes 

— Repair of control 

structure 

Annual or as 

needed 

— Removal of accumulated 

sediment from forebays 

or sediment storage areas 

when 60% of the original 

volume has been lost 

5-year cycle 

Ponds Extended 

detention 

ponds, wet 

ponds, 

multiple pond 

systems, 

“pocket” 

ponds 

3%–6% $3,000–$6,000 

— Removal of accumulated 

sediment from main cells 

of pond once 50% of the 

original volume has been 

lost 

20-year 

cycle 

— Cleaning and removal of 

debris after major storm 

events (>2” rainfall) 

— Harvesting of vegetation 

when a 50% reduction in 

the original open water 

surface area occurs 

— Repair of embankment 

and side slopes 

— Repair of control 

structure 

Annual or as 

needed 

— Removal of accumulated 

sediment from forebays 

or sediment storage areas 

when 60% of the original 

volume has been lost 

5-year cycle 

Wetlands Shallow 

wetlands, pond 

wetlands, 

“pocket” 

wetlands 

~2% $3,800 

— Removal of accumulated 

sediment from main cells 

of pond once 50% of the 

original volume has been 

lost 

20-year 

cycle 

11-10 
Management Measure 11: Operation and Maintenance 

Table 11.3 (continued).

Category 

Management 

Practice 

Annual 

Maintenance 

Cost (% of 

Construction 

Cost) 

Maintenance 

Cost for a 

“Typical” 

Application Maintenance Activity Schedule 

— Removal of accumulated 

sediment from forebays 

or sediment storage areas 

when 60% of the original 

volume has been lost 

Infiltration 5-year cycle 

trench 

5%–20% $2,300–$9,000 

— Removal of accumulated 

sediment from main cells 

of pond once 50% of the 

original volume has been 

lost 

20-year 

cycle 

1%–3% $150–$450 — Cleaning and removal of 

debris after major storm 

events; (>2” rainfall) 

— Mowing and 

maintenance of upland 

vegetated areas 

— Sediment cleanout 

Annual or as 

needed 

Infiltration 

practices 

Infiltration 

basin 

5%–10% $750–$1,500 — Removal of accumulated 

sediment from forebays 

or sediment storage areas 

when 50% of the original 

volume has been reduced 

3- to 5-year 

cycle 

— Mowing and litter/debris 

removal 

— Stabilization of eroded 

side slopes and bottom 

— Nutrient and pesticide 

use management 

— Dethatching of swale 

bottom and removal of 

thatching 

— Discing or aeration of 

swale bottom 

Annual or as 

needed 

Open 

channel 

practices 

Dry swales, 

grassed 

channels, 

biofilters 

5%–7% $200–$2,000 

— Scraping of swale 

bottom, and removal of 

sediment to restore 

original cross-section 

and infiltration rate 

— Seeding or sodding to 

restore ground cover (use 

proper erosion and 

sediment control) 

5-year cycle 

 11-11 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Table 11.3 (continued).

Category 

Management 

Practice 

Annual 

Maintenance 

Cost (% of 

Construction 

Cost) 

Maintenance 

Cost for a 

“Typical” 

Application Maintenance Activity Schedule 

— Removal of trash and 

debris from control 

openings 

— Repair of leaks from the 

sedimentation chamber 

or deterioration of 

structural components 

— Removal of the top few 

inches of sand, and 

cultivation of the surface, 

when filter bed is 

clogged 

Annual or as 

needed 

Sand filters 11%–13% $2,200 

— Clean-out of 

accumulated sediment 

from filter bed chamber 

once depth exceeds 

approximately 1⁄2 inch, or 

when the filter layer will 

no longer draw down 

within 24 hours 

— Clean-out of 

accumulated sediment 

from sedimentation 

chamber once depth 

exceeds 12 inches 

3- to 5-year 

cycle 

— Repair of erosion areas 

— Mulching of void areas 

— Removal and 

replacement of all dead 

and diseased vegetation 

— Watering of plant 

material 

Biannual or 

as needed 

Bioretention 5%–7% $3,000–$4,000 

— Removal of mulch and 

application of a new 

layer 

Annual 

Filtration 

practices 

Filter strips $320/acre 

(maintained) 

$1,000 — Mowing and litter/debris 

removal 

— Nutrient and pesticide 

use management 

— Aeration of soil on the 

filter strip 

— Repair of eroded or 

sparse grass areas 

Annual or as 

needed. 

11-12 
Management Measure 11: Operation and Maintenance 

11.3.3.3 Ponds and wetlands 

Extended dry detention ponds are submerged only during storms and are dry between storms. 

Depending on the type of vegetative cover used, they may require mowing at least once a month 

to maintain turf grass cover, or once a year to prevent the establishment of woody vegetation. 

Sediments should be removed when they are dry and cracked to separate them from vegetation 

more easily. Pilot or low-flow channels require inspection to prevent undermining of concrete 

channels and overgrowth of stone channels. Inlets and outlets should be cleared of sediment and 

debris to prevent clogging. 

Wet ponds are susceptible to algae blooms as a result of high nitrogen levels and may need to be 

cleaned periodically. Sediments that accumulate in the pond inlet or forebay should be removed 

more frequently than fine sediment, which collects near the pond outlet. Sediment removal 

requires draining the pond (some water to maintain fish populations should be left), collection of 

solids, and drying and testing of the residuals before disposal. Pond water should be disposed of 

in a locally approved manner; it should be tested for pollutants and released to the receiving 

water, if allowed, or pumped and hauled to a disposal facility. During the period in which the 

stockpiled materials are drying, erosion controls should be implemented to prevent sediment 

loss. All structures and surrounding areas should be inspected for leakage, seepage, corrosion, 

and wear and tear. Inspectors and crews should pay special attention to structural integrity to 

ensure that ponds operate safely. 

Constructed wetlands should be inspected approximately four times per year to determine if they 

are retaining and discharging storm water at an appropriate rate and whether maintenance is 

needed. Constructed wetlands require periodic cropping; removal of trash, weeds, invasive 

species, or woody vegetation; repair of animal burrows in embankments; and clearing of inlets 

and outlets. Side slopes should be stabilized with vegetative cover to prevent erosion. Wetland 

plants should be thinned and transplanted as necessary to maintain adequate cover throughout the 

wetland. In general, semiannual sediment removal is recommended to ensure that treatment 

capacity is maintained. Mosquitoes may be a problem in some areas, and introducing natural 

predators such as mosquito fish (Gambusia) can be one method of control. Consultation with a 

wetland scientist is recommended to ensure that the constructed wetland functions as intended. 

11.3.3.4 Infiltration practices 

Infiltration practices, such as basins, trenches, vegetated swales, and porous pavement, are 

subject to clogging from sediment, oil, grease, and microbes. Clogging impairs their 

effectiveness in reducing runoff volume and pollutant loading to downstream waters. When 

clogging occurs, standing water tends to collect. Seasonal water table fluctuations or ground 

water mounding can also cause standing water. Facility inspection during dry periods will 

identify whether standing water is present and provide clues to the possible causes. Inspections 

should include a site assessment of the contributing drainage area because sediment 

accumulation in a facility stems from erosion in surrounding areas that can be prevented if the 

areas are adequately stabilized. The frequency of required maintenance depends on loads from 

the contributing drainage areas. 

 11-13 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

If clogging results in pooling, sediment can be removed to restore the facility to its original 

capacity. If the standing water results from high water table conditions, the facility owner should 

consider converting the site to a permanent pool facility such as a constructed wetland or 

detention pond. For systems designed with filter fabric to collect sediments, periodic inspections 

can identify when and where the mesh should be replaced. In cold climates where street sanding 

occurs in the winter, the filter fabric in infiltration devices adjacent to roads and parking lots 

should be replaced prior to spring. 

Promotion of a vegetative cover will help to maintain percolation rates, slow runoff velocity, and 

minimize ground water pollution. To maintain aeration and permeability, nonvegetated basins 

require tilling or disking and leveling after sediment is removed. Vegetated filters adjacent to 

infiltration trenches should be cleared of sediments periodically to prevent sediment loading to 

the trench. 

Regular monitoring of infiltration rates after storms will indicate when maintenance is required 

to maintain the system’s treatment design capacity. 

11.3.3.5 Filtration practices 

Filtration practices include media filters (typically sand) and biofilters. Sand filters contain two 

phases: a sedimentation chamber and a filtration chamber. The sedimentation chamber can be 

inspected by measuring to determine if the deposited sediments are becoming deep enough to 

interfere with the filtration chamber. Different types of sand filters require different levels of 

maintenance. The Austin sand filter system usually requires maintenance every five to 10 years, 

depending on the stability of soils in the contributing areas, and can be treated like a dry 

detention facility. The filter component can be raked of fine sediments or skimmed with a shovel 

to restore permeability. The Washington and Delaware sand filter sedimentation chambers, 

which maintain a pool of water, should be vacuumed to remove sediment when inspections 

identify accumulation greater than 75 percent of capacity. Filtration chambers for these systems 

may need to be cleaned of fine particles as frequently as twice per year to maintain their 

efficiency and prevent overflows. A flat-bottomed shovel can be used to remove the sedimentladen filter media and roughen surfaces to improve permeability. 

Each system should be inspected for vandalism, leaks, cracks, or damage to concrete at least 

once per year. These problems should be remedied immediately. Forebays should be pumped or 

cleaned as necessary. All materials removed from the systems should be tested for contamination 

and to identify how the material should be disposed of (e.g., as clean fill, in a landfill, or as a 

hazardous waste). 

Biofiltration system vegetation should be mowed periodically to maintain an optimum height 

(2 to 6 inches) that maximizes infiltration and minimizes runoff velocity. Special effort should be 

made to promote native species and exclude invasive species, which can grow too vigorously 

and reduce treatment capacity. Some natural vegetation replacement is desirable, such as wetland 

plants that colonize a low-lying biofilter. Inspection and maintenance records should reflect these 

changes. 

11-14 
Management Measure 11: Operation and Maintenance 

Biofiltration facilities should be inspected and maintained regularly. Sediment removal is an 

important and sometimes expensive part of biofilter maintenance. Sediment should be removed 

when it fills 20 percent of the design depth in any spot or starts to cover vegetation. Efforts 

should be made to return the system to its original topographic and vegetative condition once the 

sediment has been removed. Inlets and outlets should be cleared of particles and debris to 

prevent backups and overflows. Biofiltration systems may also need periodic replacement or 

amendment of system soils if clogging has occurred. 

Maintenance equipment for the tasks described previously, along with purchase and rental costs, 

is presented in Table 11.4. 

Table 11.4: Typical O&M equipment and material costs (WMI, 1997). 

Equipment Purchase Rent (per day) 

Grass Maintenance 

Hand mower $300–$500 $25–$50 

Riding mower $3,000–$7,000 $75–$150 

Tractor mower $20,000–$30,000 $150–$450 

Trimmer/edger $200–$500 $25–$35 

Spreader $100–$200 $20–$30 

Chemical sprayer $200–$500 $25–$40 

Vegetative Cover Maintenance

Hand saw $15–$20 $5 

Chain saw $300–$800 $15–$35 

Pruning shears $25–$40 $5 

Shrub trimmer $200–$300 $25–$35 

Brush chipper $2,000–$10,000 $100–$300 

Sediment, Debris, and Trash Removal

Vactor truck $100,000–$250,000 $700–$1,200 

Front-end loader $60,000–$120,000 $250–$500 

Backhoe $50,000–$100,000 $250–$500 

Excavator >$100,000 $400–$1,000 

Grader >$100,000 $400–$1,000 

Transportation

Van $18,000–$30,000 $50–$100 

Pickup truck $15,000–$25,000 $50–$100 

Dump truck $40,000–$80,000 $100–$200 

Light-duty trailer $3,000–$6,000 $50–$100 

Heavy-duty trailer $10,000–$20,000 $100–$250 

Miscellaneous

Shovel $15 $5 

Rake $15 $5 

Pick $20 $5 

Wheelbarrow $100–$250 $15–$25 

Portable compressor $800–$2,000 $50–$150 

Portable generator $750–$2,000 $50–$150 

Concrete mixer $750–$1,500 $50–$100 

Welding equipment $750–$2,000 $50–$100 

Materials

Topsoil $35–$50/cubic yard 

Fill Soil $15–$30/cubic yard 

Grass seed $5–$10/pound 

Soil amenities $0.10–$0.25/square foot 

 11-15 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

Table 11.4 (continued). 

Equipment Purchase Rent (per day) 

Materials (continued)

Chemicals $10–$30/gallon 

Mulch $25–$40/cubic yard 

Dry mortar mix $5/50-pound bag 

Concrete delivered $60–$100/cubic yard 

Machine/motor lubricants $5–$10/gallon 

Paint $20–$40/gallon 

Paint Remover $10–$20/gallon 

11-16 
Management Measure 11: Operation and Maintenance 

11.4 Information Resources 

The South Carolina Department of Health and Environmental Control (2000) published A 

Citizen's Guide to Stormwater Pond Maintenance in South Carolina, which is available for 

download in PDF format at http://www.scdhec.net/eqc/admin/html/eqcpubs.html. The booklet is 

intended as a guide for homeowners’ associations and others responsible for the proper 

maintenance of storm water ponds. Photos and descriptions of nuisance aquatic plant species are 

presented in the guide to aid in identifying these species and removing them from ponds. Copies 

of the guide are available from Ward Reynolds at 843-747-4323. 

The Stormwater Manager’s Resource Center (CWP, no date) has sample O&M checklists 

available for download from its Web site (http://www.stormwatercenter.net/). When at the site’s 

homepage, click on “Manual Builder” and choose “Construction and Maintenance Checklists” 

from the pull-down list. There are checklists for the following practices: ponds, infiltration 

trenches, infiltration basins, bioretention facilities, sand filters, and open channel practices. 

 11-17 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

11.5 References 

Bell, W.B. 1997. BMP Maintenance Agreements and Responsibilities. Presented at the 

Stormwater BMP Maintenance Workshop, May 20, 1997, Linthicum, MD. 

Center for Watershed Protection (CWP). No date. Construction and Inspection Checklists.

Stormwater Manager’s Resource Center. http://www.stormwatercenter.net/. Accessed 

March 29, 2002. 

Center for Watershed Protection (CWP). 1998. Costs and Benefits of Storm Water BMPs: Final 

Report 9/14/98. Center for Watershed Protection, Ellicott City, MD. 

Delaware County Departments of Planning and Public Works. 2003. Stormwater Management: 

Delaware County Action Plan. Version 1. 

Field, R. and M.L. O’Shea. 1994. The handling and disposal of residuals from the treatment of 

urban stormwater runoff from separate storm drainage systems. Waste Management and 

Research 12: 527–539. 

Lenhart, J.H. and R. Harbaugh. 2000. Maintenance of Stormwater Quality Treatment Facilities. 

http://www.stormwaterinc.com/pdfs/maintenance_facil.pdf. Accessed July 24, 2003. 

Lindsey, G., L. Roberts and William Page. 1992. Maintenance of Stormwater BMPs in Four 

Maryland Counties: A Status Report. Journal of Soil and Water Conservation 47(5): 

417–422. 

Marquette University. 1982. Characteristics and Treatability of Urban Runoff Residuals.

Prepared for U.S. EPA, Municipal Environmental Research Laboratory, Cincinnati, OH. 

Schueler, T. and Y.L. Yousef. 1994. Pollutant Dynamics of Pond Muck. Watershed Protection 

Techniques 1(2). 

South Carolina Department of Health and Environmental Control. 2000. A Citizen’s Guide to 

Stormwater Pond Maintenance in South Carolina. South Carolina Department of Health 

and Environmental Control, Office of Ocean and Coastal Resource Management, 

Columbia, SC. 

U.S. Environmental Protection Agency (USEPA). 1999. Storm Water O&M Fact Sheet: 

Handling and Disposal of Residuals. EPA 832-F-99-015. 

http://www.fxbrowne.com/html/gs-facts/handdisp.pdf. Accessed July 1, 2003. 

U.S. Environmental Protection Agency (USEPA). 2000. Model Ordinances to Protect Local 

Resources. http://www.epa.gov/nps/ordinance. Last updated October 29, 1999. Accessed 

August 14, 2000. 

Watershed Management Institute (WMI). 1997. Operation, Maintenance, and Management of 

Stormwater Management Systems. Watershed Management Institute, Inc., 

Crawfordville, FL. 

11-18 
Management Measure 12: Evaluate Program Effectiveness 

MANAGEMENT MEASURE 12 

EVALUATE PROGRAM EFFECTIVENESS 

12.1 Management Measure 

Develop and implement a program to evaluate and improve the effectiveness of the urban runoff 

management program. 

12.2 Management Measure Description and Selection 

12.2.1 Description 

The purposes of this management measure are to: 

— Determine whether implementation of the runoff management program framework is 

protecting and/or improving water quality by evaluating management practices that are 

being used to meet Management Measure 1. If these practices aren’t effective, 

improvements to the runoff management program framework should be implemented. 

— Periodically reassess the watershed (see Management Measure 2) to determine whether 

water quality has improved or declined. Based on this assessment, each management 

measure should be reevaluated to determine whether additional practices should be 

implemented, if improvements should be made to existing practices, or if specific 

practices should be discontinued. 

12.2.2 Management Measure Selection 

This management measure was selected because runoff management programs need to be 

dynamic (i.e., they need to be periodically adjusted to respond to changing conditions and 

optimize program effectiveness and expenditures). Areas where program improvement is 

possible should be identified. Programs that are periodically reviewed and evaluated also are 

perceived as being more effective, and they will be more likely to receive the public and political 

support necessary to achieve success. The basic elements of a successful program evaluation are 

described in this management measure. 

12.3 Management Practices 

12.3.1 Assess the Runoff Management Program Framework 

It is important for watershed managers to objectively assess the runoff management program 

framework to determine whether the goals of the Program Framework and Objectives 

Management Measure (Management Measure 1) are being met. This effort should be undertaken 

periodically to identify aspects of the program that need to be strengthened or revised. Each 

 12-1 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

aspect of the program framework will require a different type of measurement. Watershed 

managers can choose from both qualitative and quantitative measures as indicators of program 

effectiveness, using the watershed baseline conditions as a point of reference (see Management 

Measure 2: Watershed Assessment). Quality assurance and quality control procedures should be 

followed regardless of whether qualitative or quantitative measures are used. 

There are several factors that should be considered when designing an evaluation program. First, 

some urban management practices, or aspects of their implementation that can be analyzed, vary 

with time of year, phase of construction, or length of time after installation. Another 

consideration is that variables generally will not directly relate to management measure 

implementation, as most urban management measures are combinations of several management 

practices. Evaluation of management measure implementation, therefore, usually will be based 

on separate assessments of two or more management practices, and the implementation of each 

management practice will be based on a unique set of variables. Finally, it is very important to 

consider the purpose of the program when selecting the variables for which the information is 

collected. 

EPA has developed the Web-based Measurable Goals Guidance for Phase II MS4s to assist 

small municipal separate storm sewer system (MS4) owners and operators in complying with the 

requirement to select measurable goals to evaluate the effectiveness of individual control 

measures and the storm water management program as a whole. Even though this document is 

intended for use by NPDES-permitted MS4 operators, it contains guidance valuable to any 

institution developing a storm water management program that includes management practices 

and methods for program evaluation. It includes examples of management practices with 

corresponding measurable goals and environmental indicators that can be used to document the 

effectiveness of both management practices and storm water programs. The guidance is available 

online at http://cfpub.epa.gov/npdes/stormwater/measurablegoals/index.cfm. 

12.3.1.1 Qualitative measures 

Urban runoff management programs can be evaluated using any number of qualitative measures, 

such as those presented by WMI (1997a): 

— Project permit review times 

— Frequency of inspections 

— Evaluation by targeted groups 

— Appearance of control practices on sites 

— Response time for complaints 

— Number of permits issued 

— Number of individuals trained 

— Recognition by others 

— Enforcement actions taken 

— Maintenance activities 

— Reduced number of complaints 

For example, Delaware uses the number of individuals attending training courses and receiving 

state certification as one measure of program success. In addition to monitoring water chemistry, 

12-2 
Management Measure 12: Evaluate Program Effectiveness 

sediments, and the biological community, Florida measures program success by the number of 

local government storm water utilities implemented, as well as the number of educational and 

public involvement activities. 

Watershed managers can use a combination of measures to assess their program framework 

based on goals and priorities that were identified at the outset of program implementation. In 

addition to the qualitative measures listed above, watershed managers can track the 

implementation, operation, and maintenance of management practices as indicators of the 

success of a program framework. See Section 12.3.2 for a discussion of management practice 

tracking. 

12.3.1.2 Quantitative measures 

Another way for watershed managers to gauge the effectiveness of their runoff management 

program framework is to quantitatively determine if water quality or habitat has improved. 

Quantitative measures include: 

— Chemical monitoring of practices 

— Chemical monitoring of receiving waters 

— Biological monitoring of receiving waters (bioassessments) 

— Habitat assessments 

— Stream flow monitoring 

— Stream shoreline condition assessments 

— Sediment monitoring (deposition, chemistry) 

— Measuring the volume of material removed by street sweeping and catch basin cleaning 

— Temperature monitoring 

See the section 12.3.3, “Gauge Improvements in Water Quality Resulting from Management 

Practice Implementation” for a more thorough discussion of the different types of monitoring 

that can be used to gauge changes in water quality after practice implementation. 

12.3.1.3 Quality assurance/quality control 

An integral part of the design phase of any monitoring project is quality assurance/quality control 

(QA/QC). Development of a quality assurance project plan (QAPP) is the first step for 

incorporating QA/QC into a monitoring project. The QAPP is a critical document for the data 

collection effort inasmuch as it is used to integrate the technical and quality aspects of the 

planning, implementation, and assessment phases of the project. The QAPP documents how 

QA/QC elements will be implemented throughout a project’s life. It states expectations and 

requirements and provides procedures for data collection and data management that are specific 

to the project. Development and implementation of a QA/QC program, including preparation of 

a QAPP, can require up to 10 to 20 percent of project resources (Cross-Smiecinski and 

Stetzenback, 1994). A thorough discussion of QA/QC is provided in Chapter 5 of EPA’s 

Monitoring Guidance for Determining the Effectiveness of Nonpoint Source Controls (USEPA, 

1997). 

 12-3 
National Management Measures Guidance to Control Nonpoint Source Pollution from Urban Areas 

12.3.2 Track Management Practice Implementation 

Implementation monitoring can be used to determine the extent to which management measures 

and practices are implemented in accordance with relevant standards and specifications. This 

involves establishing a program that tracks either whether the practices have been implemented 

or whether management practices have been operating and maintained as designed. For example, 

some states and municipalities have developed programs that track and record septic tank 

maintenance or erosion and sediment control practices, or that inventory all runoff control 

structures. 

It is not always possible to track the implementation of every management practice of interest. 

Sampling a subpopulation and extrapolating the findings to the entire population may be 

preferred due to time, funding, or personnel constraints. Lack of adequate legal authority may 

also hinder the collection of data sufficient to track management practice implementation. If an 

inventory of all management practices of interest is not possible, care should be taken to prepare 

a statistically valid sampling plan. The primary basis for selecting a design approach should be 

based on a careful review of study objectives and the pros and cons of each sampling method. An 

extensive discussion of the different sampling designs and methods for analysis can be found in 

Techniques for Tracking, Evaluating, and Reporting the Implementation of Nonpoint Source 

Control Measures: Urban (USEPA, 2000), which is available on EPA’s Nonpoint Source Web 

site at http://www.epa.gov/owow/nps/urban2.html. Below are several tools that can be used to 

track management practice implementation. 

12.3.2.1 Track permits 

States and local agencies employ a variety of legal mechanisms, including nuisance prohibitions, 

general water pollution discharge prohibitions, land use planning and regulation laws, building 

codes, health regulations, and criminal laws to regulate urban nonpoint source water pollution 

(Environmental Law Institute, 1997). Although not all pollutant-generating activities are covered 

by these mechanisms, they present opportunities for inventorying management practice 

implementation. Activities that are typically regulated in some manner include erosion and 

sediment control, onsite sewage disposal systems, runoff from development sites, construction 

activities, and industrial activities. A permitting system places on the applicant the burden of 

obtaining and supplying all necessary data and information to obtain the permit. Issuance of 

these permits encourages compliance with local laws and regulations in the construction and 

operation of management practices. 

12.3.2.2 Use operation and maintenance records 

In many instances, proper operation and maintenance of a management practice are as important 

as proper design and installation. Regular inspection of management practices can identify the 

need for repairs or retrofits in addition to identifying areas in the watershed that require 

additional management resources. If the right types of information are collected when a 

management practice is installed, it becomes much easier to track operation and maintenance 

activities and ascertain the cost and effectiveness of the practice. 

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Management Measure 12: Evaluate Program Effectiveness 

12.3.2.3 Use geographic information systems 

Geographic information systems (GISs) are useful tools for inventorying management practice 

implementation. A GIS can detect and track trends in management practice implementation, land 

treatment, changes in land use, and virtually any data related to management practices and water 

quality. Another advantage is the ability of a GIS to update information and integrate it with 

existing data in a timely manner. GISs allow watershed managers to do more than just manage 

information in a database—they are powerful analysis tools that can be used to design sampling 

protocols for tracking studies and help watershed managers analyze program effectiveness by 

integrating land treatment and water quality information. 

12.3.2.4 Develop surveys 

Surveys of property managers and developers can be used to collect background information 

about management practice implementation, such as: 

— Type, number, and size of management practices installed 

— Management practice location/watershed 

— Land use (i.e., residential, commercial, industrial) 

— Percent impervious area 

— Inspection results 

— Operation and maintenance practices 

Maryland’s GIS-Based Restoration Project Tracking Database 

The Maryland Department of Natural Resources has developed a Restoration Project Tracking 

Database that provides a list of riparian forest buffer and stream restoration projects by watershed and 

county with details such as waterway; length, width, area, and other quantifiers as appropriate; and 

details about the project such as owner type, planting reason, year established or completed, and 

project components. These data can be displayed in tabular format and are linked on the Web site to 

an interactive GIS for the public and interested parties to browse (MDNR, 2004). The database can be 

accessed at http://dnrweb.dnr.state.md.us/watersheds/surf/tracking/track_map.htm. 

Maryland also has a “BMP Tracking Reports” Web site 

(http://dnrweb.dnr.state.md.us/watersheds/surf/bmp/) that provides tributary-specific information 

regarding implementation of management practices. This information is used to help measure 

Maryland's progress in reducing nonpoint source pollution and meeting the goals of the Chesapeake 

Bay 2000 agreement. Users can choose a statewide management practice summary report or they 

can generate a report by tributary. They list 3 categories of practices: urban practices, resource 

protection and improvement practices, and agricultural practices. The data for each management 

practice type is summarized by year in units appropriate for the practice. For example, the urban 

practice “Erosion and Sediment Control” was implemented on 2,213 acres in 2000, 11,133 acres in 

2001, and 10,442 acres in 2002. More information is provided for each practice, including a photo, a 

brief description, and general pollutant removal information for different land use applications (if the 

practice is applicable in multiple settings). The pollutant removal information is limited to nitrogen, 

phosphorus, and sediment. 

To complete these efforts, Maryland DNR developed estimates from the Departments of Agriculture, 

Environment, and Natural Resources. This information was compiled from data received from 

volunteer groups and county, state, and federal reports provided to each department. 

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— Dates of management practice installation 

— Design specifications 

— Type of water body or area protected 

— Previous management practices used 

— Erosion and sediment control plans (for construction) 

— Dates of plan preparation and revisions 

— Date of initial plan implementation 

— Total acreage under management 

— Certification requirements 

Watershed managers can use the information obtained from these surveys to identify locations 

for new management practices and to more closely examine practices used upstream of waters 

known to be degraded to determine if they are operating as designed or if they require redesign 

or maintenance. 

12.3.2.5 Consider expert evaluations 

Expert evaluations may be needed to augment or verify information provided in surveys. Experts 

are especially useful in determining the following: 

— Proper design 

— Proper installation 

— Adequacy of operation and maintenance plans and activities 

— Verification of conclusions derived from self-evaluations (i.e., an objective third party’s 

review of data and reports) 

Each of these tools can be used to help watershed managers locate management practices and 

identify those that are not performing as expected (i.e., not meeting the goals of the management 

measures). These tools can be used separately or in combination to obtain and organize 

management practice data and use it to better meet the goals of the management measures. 

12.3.3 Gauge Improvements in Water Quality Resulting from Management 

Practice Implementation 

Watershed managers can determine the effectiveness of the runoff program by monitoring 

changes in water quality after the management measures and practices are implemented. The 

most fundamental step in the development of a monitoring plan is to define the goals of the 

monitoring program. Monitoring goals are broad statements such as “to measure improvements 

in Elephant Butte Reservoir” or “to verify nutrient load reductions into the Chesapeake Bay.” 

Designing a monitoring plan also includes selecting sampling variables, a sampling strategy, 

station locations, data analysis techniques, the length of the monitoring program, and the overall 

level of effort to be invested. 

Once the monitoring goals have been established, existing data and constraints should be 

considered. A thorough review of literature pertaining to water quality studies previously 

conducted in the geographic region of interest should be completed before starting a new study. 

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Management Measure 12: Evaluate Program Effectiveness 

The review should help determine whether existing data provide sufficient information to 

address the monitoring goals and what data gaps exist. 

The next step should be to identify project constraints such as finances, staffing, and time. Clear 

and detailed information should be obtained on the time frame for management decisions, the 

amounts and types of data that must be collected, the level of effort required to collect them, and 

the equipment and personnel needed to conduct the monitoring. This will determine whether 

available personnel and budget are sufficient to implement or expand the monitoring program. 

As with its design, the program’s level of monitoring is largely determined when goals and 

objectives are set, although there is some flexibility for achieving most monitoring objectives. 

Watershed managers should determine the appropriate timeframe and geographic scope of the 

monitoring program based on program goals and objectives. For example, if the objective is to 

determine the effectiveness of a nutrient management program for reducing nutrient inputs to a 

downstream lake, monitoring a subwatershed for five years or longer might be necessary. 

Watershed managers also need to determine the size of the watershed, because many have an 

influence on stream characteristics and water quality, and therefore on the complexity of the 

monitoring program design. These factors include drainage patterns, stream order, stream type, 

climate, number of landowners in the area, homogeneity of land uses, watershed geology, and 

geomorphology. An analysis of these considerations in combination with budgetary and time 

constraints will determine the exact nature of the monitoring program. 

It is important to ensure that expectations for the monitoring program are realistic. Ward et al. 

(1990) identify the following key steps to ensure that policymakers and other stakeholders know 

the types of information that a monitoring program can produce: 

— Perform a thorough review of the legal basis for the management effort and define the 

resulting implications for monitoring. 

— Review the administrative structure and procedures developed from the law in order to 

define the information expectations of the management staff. 

— Review the ability of the monitoring program to supply information. 

— Formulate an information expectations report for the monitoring system. 

— Present the information expectations report to all users of the information. 

— Develop consensus as to an agreeable formulation of information expectations and 

related monitoring system design criteria. 

The next task when developing a monitoring program plan is to set monitoring objectives, which 

are more specific statements than goals and can be used to complete the monitoring design 

process. The objectives must be detailed enough to allow the designer to define precisely what 

data will be gathered and how the resulting information will be used. 

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Another important aspect of setting up a monitoring and evaluation program is variable selection. 

Variables should be selected based on the monitoring objectives. For example, if a dissolved 

oxygen problem is suspected, then dissolved oxygen should be monitored in addition to 

biochemical oxygen demand, sediment oxygen demand, temperature, and nutrients. Surrogate 

measures can also be used to satisfy monitoring objectives. For example, if the objective is to 

monitor the condition of salmon spawning areas, surrogate measures are necessary because the 

condition of salmon spawning areas is a composite of many factors. Good surrogate variables 

would be stream bank undercut, embeddedness, and vegetative overhang (Platts et al., 1983). 

The corresponding surrogate goals could be to reduce cobble embeddedness and to increase 

vegetative overhang to appropriate levels for salmon spawning. Subsequent monitoring goals 

could be to document changes in cobble embeddedness and vegetative overhang. 

Because there are numerous variables to choose from and monitoring budgets are limited, some 

method to prioritize variable selection is often necessary. Table 12.1 shows groups of variables 

and examples of each. When available, existing data should be used to guide variable selection. 

Further discussion on variable selection, prioritization, and optimization are provided by USDA 

(1996), MacDonald et al. (1991), and Sherwani and Moreau (1975). In some cases, optimal 

variable selection is not possible, which may be due to lack of local data. In such cases, the 

researcher might need to rely on professional judgement and the review of monitoring programs 

of similar nature and scope. 

Table 12.1: Examples of variables that can be measured to assess changes in management 

practice implementation and water quality. 

Variable Type Examples 

Physical and 

chemical water 

quality data 

Flow (streams), temperature, transparency, suspended sediment, sedimentation 

transparency, suspended sediment, sedimentation rate, dissolved oxygen, pH, conductivity, 

alkalinity/acid neutralizing capacity (lakes), and nutrients. 

Biological data Bacteria, algal biomass, macrophyte biomass and location, macroinvertebrate and fish 

populations. 

Precipitation data Total rainfall, rainfall intensity, storm interval, and storm duration. 

Land use data Treatments applied to land, current and historical use of the land, spatial and temporal 

information on land use activities, and changes in land use made before and during a 

project. 

Topographic data Slope length, slope steepness, slope shape, channel slope, channel side slope. 

Soil characteristics 

data 

Hydrologic soil group, soil organic carbon content, depth to water, net recharge, aquifer 

media, and vadose zone characteristics. 

Designing and implementing a monitoring program often requires an interdisciplinary approach 

that may require interagency coordination and input. In many cases, technical staff will need to 

integrate “new” monitoring with what is already being done to demonstrate to program managers 

that duplicate work is not proposed. The most effective way to achieve this goal is to bring all 

the involved agencies and other stakeholders in the monitoring effort together. One or more 

agencies should coordinate to clarify project roles and responsibilities. Agreements to participate 

can be formalized as commitments and specified in the quality assurance project plan. 

Such coordinated cooperation permits each involved party to offer the results of its ongoing 

activities to the monitoring effort, lessens the burden on each participating agency, and may 

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Management Measure 12: Evaluate Program Effectiveness 

decrease overall project costs. For example, USGS might already have a tracking system for 

management practices, while other agencies, including the U.S. Fish and Wildlife Service and 

EPA, might have other ongoing monitoring programs. When multiple agencies are involved in 

the monitoring program, each can benefit from the others’ efforts. 

Two types of objectives will be discussed in this section: analyzing trends in water quality and 

measuring the effectiveness of management practices. 

12.3.3.1 Conduct trend monitoring 

Trend monitoring can be useful for determining whether there has been a change in the extent to 

which management measures and management practices are being implemented. Trend 

monitoring involves long-term tracking of changes in one or more parameters. Public attitudes, 

land use, and the use of various urban management practices are examples of parameters that 

could be measured with trend monitoring. 

Isolating the impacts of either individual or sets of management measures and management 

practices on water quality also requires trend monitoring. Because trend monitoring involves 

measuring a change (or lack thereof) in some parameter over time, it is necessarily of longer 

duration and requires establishment of a baseline. Any changes in the measured parameter are 

then detected in reference to the baseline. Baseline monitoring requires ascertaining the existing 

conditions before some management action or change in land use occurs. Factors such as 

weather conditions should be considered if baseline monitoring is to be used as a reference point 

for trend analysis and management decisions. The ability to relate water quality changes to 

changes in land management depends on the quality and quantity of data collected on land 

management practices. 

Public attitudes, land use, and the use of various urban management practices are examples of 

parameters that could be measured with trend monitoring. Isolating the impacts of management 

measures and management practices on water quality also requires trend monitoring. For 

example, an objective of trend analysis can be to answer the question, “Is water quality changing 

over time?” 

12.3.3.2 Conduct effectiveness monitoring 

Effectiveness monitoring involves evaluating individual management practices or groups of 

management practices to determine the extent of pollution control they provide. Monitoring for 

individual management practices can typically be conducted on a plot or field scale, whereas 

monitoring for management practice systems is usually conduced on a watershed scale. Studies 

of some individual practices can be conducted in a relatively short time (less than five years), 

while others might take longer. Evaluation of management practice systems is typically 

conducted over a long term (more than five years) because management practice implementation 

can take years to affect water quality. In fact, there may be a lag in response time that may be 10 

to 20 years or longer. This type of monitoring is difficult due to the presence of pollutant 

reserves in soil and sediments, the effect of many land uses within a study area, the variety of 

approaches that landowners use to implement similar management practice systems, and the 

need to track land management as well as water quality and climatic variables. 

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A guidance manual describing protocols for monitoring the effectiveness of storm water 

management practices, Urban Stormwater BMP Performance Monitoring, is available for 

download in PDF format from the International Stormwater Best Management Practices 

Database Web site (http://www.bmpdatabase.org/docs/Urban Stormwater BMP Performance 

Monitoring.pdf). Along the same lines, EPA’s Environmental Technology Verification Center 

offers the Protocol for the Verification of Stormwater Source Area Treatment Technologies

(http://www.epa.gov/etv/pdfs/vp/04_vp_stormwater.pdf). 

12.3.4 Develop and Implement a Schedule to Improve the Management Program 

Framework 

Data on management practice effectiveness and water quality should be carefully reviewed to 

determine where deficiencies in the runoff management exist. Effectiveness monitoring results 

should be compared with expected values published in the literature or with values provided with 

proprietary products. If the system is underperforming, possible causes should be considered: 

— Is the practice properly designed and sized? 

— Are site conditions (geology, land use, etc.) inappropriate for this practice? 

— Were maintenance activities not performed as scheduled or needed? 

— Were influent pollutant concentrations different than expected? 

The next step is to determine whether the management practice needs to be retrofitted, replaced, 

or removed. Is pretreatment needed? Should a treatment train approach be used? Should 

additional capacity be added? Should maintenance be scheduled more frequently? A plan should 

be developed to implement proposed changes on a practice-by-practice basis. 

A review of monitoring data on ambient water quality should be conducted to determine if water 

quality is improving. Consideration should be given to activities or events that might have 

skewed results (i.e., flooding, drought, landslides, significant changes in surrounding land use). 

If water quality has not improved, the following questions should be asked: 

— Are management practices not performing as well as they should be? 

— Were the wrong practices selected? 

— Are additional practices needed? 

Monitoring data should be examined to determine which pollutants and sources (if known) are a 

problem, and additional activities to address these sources should be proposed. 

Once a list of planned changes to the program has been compiled, each project should be 

prioritized. Projects that should receive a higher priority are those that are most likely to improve 

water quality, those that the community has shown support for or is likely to support, and those 

that are relatively straightforward or inexpensive to implement. Implementation of proposed 

projects should be completed before the next program evaluation (usually within five years). 

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Management Measure 12: Evaluate Program Effectiveness 

12.4 Information Resources 

Restoring Life in Running Waters: Better Biological Monitoring (Karr, 1998) describes how and 

why biological monitoring and multi-metric indices can be used to assess environmental 

degradation and how this information can be integrated into regulatory and policy decisions. This 

book can be purchased at bookstores or ordered from Island Press at 

http://www.islandpress.com/. 

Monitoring Guidance for Determining the Effectiveness of Nonpoint Source Controls, published 

by EPA's Office of Water in 1997, gives an overview of nonpoint source pollution and covers the 

development of a monitoring plan, data analysis, quality assurance/quality control, and biological 

monitoring. It can be ordered through EPA’s National Service Center for Environmental 

Publications at http://www.epa.gov/ncepihom/index.htm. 

Techniques for Tracking, Evaluating, and Reporting the Implementation of Nonpoint Source 

Control Measures: Urban (USEPA, 1998) helps local officials to focus limited resources by 

establishing statistical sampling to assess, inspect, or evaluate a representative set of 

management practices, erosion and sediment controls, and onsite wastewater treatment systems. 

The document can be downloaded in PDF format at http://www.epa.gov/owow/nps/urban.pdf, or 

it can be ordered through EPA’s National Service Center for Environmental Publications at 

http://www.epa.gov/ncepihom/index.htm. 

EPA’s Volunteer Monitoring Program provides technical assistance, serves as a regional contact 

for volunteer programs, manages grants to state agencies that organize volunteer monitoring 

programs, and provides information exchange services for volunteers. A listserver is available 

for volunteer monitoring program coordinators on the EPA Web site, 

http://www.epa.gov/owow/monitoring/volunteer. Also available are a national newsletter for 

volunteer monitors, a directory of volunteer monitoring programs, and manuals on volunteer 

monitoring methods and planning and implementing volunteer programs. 

Urban Stormwater BMP Performance Monitoring: A Guidance Manual for Meeting the National 

Stormwater BMP Database Requirements presents monitoring protocols for studies measuring 

the effectiveness of storm water management practices and is available for download in PDF 

format from the International Stormwater Best Management Practices Database Web site 

(http://www.bmpdatabase.org/docs/Urban Stormwater BMP Performance Monitoring.pdf). 

EPA’s Environmental Technology Verification Center developed the Protocol for the 

Verification of Stormwater Source Area Treatment Technologies

(http://www.epa.gov/etv/pdfs/vp/04_vp_stormwater.pdf), which establishes guidelines for 

measuring the effectiveness of storm water treatment technologies. The protocol was developed 

to ensure that technology verification studies are carried out in a consistent and objective manner 

that assesses the appropriate performance characteristics. 

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12.5 References 

Cross-Smieckinski, A., and L.D. Stetzenback. 1994. Quality Planning for the Life Science 

Researcher: Meeting Quality Assurance Requirements. CRC Press, Boca Raton, FL. 

Environmental Law Institute (ELI). 1997. Enforceable State Mechanisms for the Control of 

Nonpoint Source Water Pollution. Environmental Law Institute Project 970300, 

Washington, DC. 

Karr, J.R., and E.W. Chu. 1998. Restoring Life in Running Waters: Better Biological Monitoring. 

Island Press, Washington, DC. 

MacDonald, L.H., A.W. Smart, and R.C. Wissmar. 1991. Monitoring Guidelines to Evaluate 

Effects of Forestry Activities on Streams in the Pacific Northwest and Alaska. EPA-910-

9-91-001. U.S. Environmental Protection Agency, Region 10, Seattle, WA. 

Maryland Department of Natural Resources (MDNR). 2004. Watershed Projects. 

http://www.dnr.state.md.us/watersheds/surf/proj/proj.html. Last updated March 26, 2004. 

Accessed March 31, 2004. 

Platts, W.S., W.F. Megahan, and G.W. Minshall. 1983. Methods for Evaluating Stream, 

Riparian, and Biotic Conditions. General Technical Report INT-138. U.S. Department of 

Agriculture, Forest Service, Ogden, UT. 

Sherwani, J.K., and D.H. Moreau. 1975. Strategies for Water Quality Monitoring. Report 107, 

Water Resources Research Institute of the University of North Carolina, Raleigh, NC. 

U.S. Department of Agriculture (USDA). 1996. National Handbook on Water Quality 

Monitoring. National Water Quality Handbook, Part 600. U.S. Department of 

Agriculture, Natural Resources Conservation Service, Washington, DC. 

U.S. Environmental Protection Agency (USEPA). 1997. Monitoring Guidance for Determining 

the Effectiveness of Nonpoint Source Controls. EPA 841-B-96-004. U.S. Environmental 

Protection Agency, Office of Water, Washington, DC. 

U.S. Environmental Protection Agency (USEPA). 1998. Techniques for Tracking, Evaluating, 

and Reporting the Implementation of Nonpoint Source Control Measures: Urban. 

EPA 841-B-00-007. U.S. Environmental Protection Agency, Office of Water, 

Washington, DC. 

Ward, R.C., J.C. Loftis, and G.B. McBride. 1990. Design of Water Quality Monitoring Systems. 

Van Nostrand Reinhold Company, NY. 

Watershed Management Institute (WMI). 1997a. Institutional Aspects of Urban Runoff 

Management: A Guide for Program Development and Implementation. Watershed 

Management Institute, Ingleside, MD. 

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Management Measure 12: Evaluate Program Effectiveness 

Watershed Management Institute (WMI). 1997b. Operation, Maintenance, and Management of 

Stormwater Management Systems. Watershed Management Institute, Ingleside, MD. 

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