June 2002
Development Document for Proposed Effluent Guidelines

and Standards for the Construction and Development

Category

June 2002

United States Environmental Protection Agency

Office of Water (4303T)

1200 Pennsylvania Avenue, NW

Washington, DC 20460

www.epa.gov/waterscience/guide/

[EPA-821-R-02-007]
Acknowledgments and Disclaimer

The Construction and Development Effluent Guidelines proposed rule and support documents

were prepared by the C&D Project Team: Eric Strassler, Project Manager; Jesse Pritts, P.E.,

Engineer; George Denning, Economist; Karen Maher, Environmental Assessor; and Michael G.

Lee, Attorney. Technical support for this Development Document was provided by Tetra Tech,

Inc.

Neither the United States government nor any of its employees, contractors, subcontractors or

other employees makes any warranty, expressed or implied, or assumes any legal liability or

responsibility for any third party's use of, or the results of such use of, any information,

apparatus, product or process discussed in this report, or represents that its use by such a third

party would not infringe on privately owned rights. Mention of trade names or commercial

products does not constitute endorsement by EPA or recommendation for use.
Development Document for Construction and Development Proposed Effluent Guidelines

June 2002 i

Contents

SECTION 1: SUMMARY AND SCOPE

1.1 Introduction ................................................................. 1-1

1.2 Summary and Scope of Proposal ................................................ 1-1

SECTION 2: BACKGROUND

2.1 Legal Authority .............................................................. 2-1

2.2 Clean Water Act ............................................................. 2-1

2.2.1 Best Practicable Control Technology Currently Available ...................... 2-2

2.2.2 Best Conventional Pollutant Control Technology ............................. 2-3

2.2.3 Best Available Technology Economically Achievable ......................... 2-3

2.2.4 New Source Performance Standards ....................................... 2-3

2.2.5 Pretreatment Standards for Existing Sources and Pretreatment Standards for New

Sources .............................................................. 2-4

2.2.6 Effluent Guidelines Schedule ............................................ 2-4

2.2.7 NPDES Phase I and II Storm Water Rules .................................. 2-5

2.3 Pollution Prevention Act of 1990 ............................................... 2-5

2.4 State Regulations ............................................................ 2-6

2.5 References .................................................................. 2-6

SECTION 3: DATA COLLECTION

3.1 Introduction ................................................................. 3-1

3.2 Literature Search ............................................................. 3-1

3.3 Compilation of State and Municipal Existing Control Strategies, Criteria, 

and Standards .............................................................. 3-1

3.4 Other Data Sources ........................................................... 3-5

3.4.1 Phase II Storm Water Rule Economic Analysis .............................. 3-5

3.4.2 USDA National Resource Inventory ....................................... 3-5

3.4.3 National Storm Water BMP Database ...................................... 3-5

3.4.4 BMP Design Manuals and Guidance Documents Developed by Governmental and 

Other Organizations .................................................... 3-6

3.5 References .................................................................. 3-6

SECTION 4: INDUSTRY PROFILE

4.1 Introduction ................................................................. 4-1

4.2 Industry Description .......................................................... 4-1

4.2.1 Industry Definition and Classification of Subsectors by NAIC and SIC Codes ...... 4-1

4.2.2 Residential Building Construction Group ................................... 4-6

4.2.3 Nonresidential Building Construction Group .............................. 4-13
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4.2.4 Heavy Construction Subsector ........................................... 4-21

4.3 Industry Practices and Trends .................................................. 4-23

4.3.1 Overview of Construction Land-disturbing Activities ........................ 4-23

4.3.2 Construction Site Size Categories and Estimates of Amount of Disturbed Land .... 4-26

4.3.2.1 National Estimates of Disturbed Acreage ............................ 4-26

4.3.2.2 Distribution of Acreage by Project Type ............................ 4-28

4.3.2.3 Distribution of Developed Acreage by Project Size and Geography ....... 4-34

4.4 References ................................................................. 4-39

SECTION 5: TECHNOLOGY ASSESSMENT

5.1 Construction Erosion and Sediment Controls ....................................... 5-1

5.1.1 Introduction .......................................................... 5-1

5.1.2 Procedure for Technology Assessment ..................................... 5-2

5.1.2.1 Identification of Performance Goals ................................. 5-2

5.1.2.2 Goals, Environmental Impact Areas, and Assessment Scales ............. 5-3

5.1.2.3 Qualitative Versus Quantitative Assessment .......................... 5-5

5.1.3 Review of Historical Approaches to Erosion and Sediment Control .............. 5-5

5.1.4 Goals, Control Strategies, Criteria, and Standards ............................ 5-8

5.1.4.1 Goals, Control Strategies, Criteria, And Standards: How They Relate ...... 5-8

5.1.4.2 Levels of Performance or “How Well Do The Strategies Work?” ......... 5-10

5.1.4.3 Strategies, Criteria, Standards, And Enforcement ..................... 5-10

5.1.5 Control Techniques, BMP Systems ............................................. 5-14

5.1.5.1 Erosion Control and Prevention ................................... 5-14

5.1.5.1.1 Planning, Staging, Scheduling ....................... 5-14

5.1.5.1.2 Vegetative Stabilization ............................ 5-17

5.1.5.1.2.1 Grass-lined Channels ................. 5-21

5.1.5.1.2.2 Seeding ............................ 5-24

5.1.5.1.2.3 Sodding ............................ 5-27

5.1.5.1.2.4 Mulching ........................... 5-29

5.1.5.1.2.5 Geotextiles ......................... 5-33

5.1.5.1.2.6 Vegetated Buffer Strips ............... 5-35

5.1.5.1.2.7 Erosion Control Matting .............. 5-37

5.1.5.1.2.8 Topsoiling ..................... 5-40

5.1.5.2 Water Handling Practices ........................................ 5-42

5.1.5.2.1 Earth Dike ....................................... 5-42

5.1.5.2.2 Temporary Swale ................................. 5-44

5.1.5.2.3 Temporary Storm Drain Diversion ................... 5-51

5.1.5.2.4 Pipe Slope Drain .................................. 5-53

5.1.5.2.5 Stone Check Dam ................................ 5-57

5.1.5.2.6 Lined Waterways ................................. 5-59

5.1.5.3 Sediment Trapping Devices ....................................... 5-63

5.1.5.3.1 Silt Fence ....................................... 5-64

5.1.5.3.2 Super Silt Fence .................................. 5-71

5.1.5.3.3 Straw Bale Dike .................................. 5-73

5.1.5.3.4 Sediment Trap ................................... 5-76
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5.1.5.3.5 Sediment Basin ................................... 5-81

5.1.5.4 Other Control Practices ......................................... 5-88

5.1.5.4.1 Stone Outlet Structure ............................. 5-88

5.1.5.4.2 Rock Outlet Protection ............................ 5-90

5.1.5.4.3 Sump Pit ........................................ 5-93

5.1.5.4.4 Sediment Tank ................................... 5-95

5.1.5.4.5 Stabilized Construction Entrance .................... 5-96

5.1.5.4.6 Land Grading .................................... 5-98

5.1.5.4.7 Temporary Access Waterway Crossing ............... 5-100

5.1.5.4.8 Dust Control ................................... 5-103

5.1.5.4.9 Storm Drain Inlet Protection ....................... 5-106

5.1.5.4.10 Polyacrylamide (PAM) ............................ 5-108

5.1.6 Summary .......................................................... 5-112

5.2 References ................................................................ 5-124

SECTION 6: REGULATORY DEVELOPMENT AND RATIONALE

6.1 Identification of Industry Impacts ................................................ 6-1

6.1.1 Pollutant Indicators .................................................... 6-1

6.1.2 Physical/habitat Indicators ............................................... 6-4

6.2 Development of Regulatory Options ............................................. 6-5

6.3 Regulatory Options Developed for the Proposed Rule ................................ 6-7

6.3.1 Option 1 Inspection and Certification ...................................... 6-7

6.3.2 Option 2 Codify EPA CGP Requirements with Site Inspection and Certification

Provisions ............................................................ 6-9

6.3.3 Option 3 No Regulation ................................................ 6-15

6.4 References ................................................................. 6-15

SECTION 7: APPROACH TO ESTIMATING COSTS

7.1 Overview ................................................................... 7-1

7.2 Methods for Estimating Erosion and Sediment Control Costs .......................... 7-1

7.2.1 Overview ............................................................ 7-1

7.2.2 Erosion and Sediment Control Costs ....................................... 7-4

7.3 Methods for Estimating Administrative Costs ..................................... 7-13

7.3.1 Overview ........................................................... 7-13

7.3.2 Administrative Costs to Permittees ....................................... 7-13

7.3.3 Administrative Costs for General Permit Revisions .......................... 7-14

7.4 References ................................................................. 7-15

Appendices

A. State Regulations on the Control of Construction Storm Water ....................... A-1

B. Supporting Cost Data ........................................................ B-1
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Tables

Table 3-1. State or Regional Planning Authority Requirements for Water Quality Protection ... 3-3

Table 3-2. Municipal or Regional Planning Authority Requirements ...................... 3-4

Table 4-1. 1997 NAICS Subsectors, Industry Groups, and Industries Performing Construction

Activities That Might Disturb Land ....................................... 4-3

Table 4-2. 1987 SIC Industry Groups Performing Construction Activities 

That May Disturb Land ................................................. 4-5

Table 4-3. Annual Housing Construction Starts by Type and Region ...................... 4-7

Table 4-4. Residential Construction Industry Profile for 1997 ............................ 4-9

Table 4-5. Busiest Markets for Single-Family Housing Permits for 1999 .................. 4-10

Table 4-6. Busiest Markets for Multifamily Housing Permits for 1999 .................... 4-10

Table 4-7. Changes in Housing Starts by Region (1989 and 1999) ....................... 4-12

Table 4-8. Value of Construction Work for Manufacturing and Industrial Building Construction

Establishments With Payroll by Type of Construction ........................ 4-15

Table 4-9. Value of Manufacturing and Industrial Building Construction Work for 

Establishments With Payroll by Location of Construction Work, 1997 ........... 4-16

Table 4-10. Value of Construction Work for Commercial and Institutional Building Construction

Establishments With Payroll by Type of Construction, 1997 ................... 4-18

Table 4-11. Value of Commercial and Institutional Building Construction Work for 

Establishments With Payroll by Location of Construction Work, 1997 .......... 4-20

Table 4-12. Overview of Heavy Construction Industry, 1992 and 1997 .................... 4-22

Table 4-13. Acres Converted from Undeveloped to Developed State, 1992-1997 ............ 4-27

Table 4-14. New Single-Family and Multifamily Housing Units Authorized, 1995-1997 ....... 4-28

Table 4-15. Average and Median Lot Size for New Single-Family 

Housing Units Sold, 1995-1997 .......................................... 4-29

Table 4-16. Average Building Square Footage ........................................ 4-31

Table 4-17. Typical Building Sizes and Size Ranges by Type of Building .................. 4-32

Table 4-18. National Estimates of Land Area Developed Per Year, Based on Building

Permit Data ......................................................... 4-33

Table 4-19. National Estimates of Land Area Disturbed Based on National Resources Inventory

Totals .............................................................. 4-34

Table 4-20. Distribution of 14 Community Survey Permits by Site Size .................... 4-36

Table 4-21. Distribution of National Construction by Site Size and Development Type ........ 4-38

Table 5-1. Description of Levels of Performance of Three Control Strategies .............. 5-10

Table 5-2. Descriptions of Levels of Difficulty in Enforcement ......................... 5-11

Table 5-3. Scheduling Considerations for Construction Activities Enforcement ............. 5-16

Table 5-4. Conditions Where Vegetative Streambank Stabilization Is Acceptable ........... 5-20

Table 5-5. Maximum Permissible Velocities for Individual Site Conditions

for Grass Swales ..................................................... 5-22

Table 5-6. Typical Mulching Materials and Application Rates .......................... 5-31

Table 5-7. Measured Reductions in Soil Loss for Different Mulch Treatments ............. 5-32

Table 5-8. Cubic Yards of Topsoil Required for Application to Various Depths ............ 5-41

Table 5-9. Grassed Swale Pollutant Removal Efficiency Data ........................... 5-49

Table 5-10. Average Annual Operation and Maintenance Costs for a Grass Swale ........... 5-51
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Table 5-11. Recommended Pipe/Tubing Sizes for Slope Drains .......................... 5-54

Table 5-12. Slope Drain Characteristics ............................................. 5-55

Table 5-13. Maximum Slope Lengths for Silt Fences .................................. 5-65

Table 5-14. Typical Requirements for Silt Fence Fabric ................................ 5-68

Table 5-15. Slope Lengths for Super Silt Fences ...................................... 5-71

Table 5-16. Minimum Requirements for Super Silt Fence Geotextile Class F Fabric .......... 5-72

Table 5-17. Maximum Land Slope and Distances Above a Straw Bale Dam ................ 5-74

Table 5-18. Weir Length for Sediment Traps ......................................... 5-78

Table 5-19. Range of Measured Long-Term Pollutant Removal for Sediment Detention Basins . 5-79

Table 5-20. Common Concerns Associated with Sediment Traps ......................... 5-80

Table 5-21. Common Concerns Associated with Sediment Basins ........................ 5-86

Table 5-22. Riprap Sizes and Thicknesses (SHA Specifications) ......................... 5-91

Table 5-23. Application Rates for Spray-On Adhesives ................................ 5-105

Table 5-24. Turbidity Reduction Values from PAM .................................. 5-110

Table 5-25. Summary of Information on Erosion Control and Prevention 

BMPs (Sub-section 5.1.5.1) ............................................ 5-112

Table 5-26. Summary of Information on Erosion Control and Prevention 

BMPs (Sub-section 5.1.5.2) ............................................ 5-116

Table 5-27. Summary of Information on Erosion Control and Prevention 

BMPs (Sub-section 5.1.5.3) ............................................ 5-119

Table 5-28. Summary of Information on Erosion Control and Prevention 

BMPs (Sub-section 5.1.5.4) ............................................ 5-122

Table 7-1. Total Costs of Proposed Rule Options ..................................... 7-1

Table 7-2. Regional compliance Cost Adjustment Factors ............................... 7-4

Table 7-3. Construction Site ESC BMP Descriptions and Site Thresholds .................. 7-5

Table 7-4. Components of Existing State Erosion and Sediment Control Requirements ........ 7-7

Table 7-5. State Acreage Equivalent to Proposed Option 2 .............................. 7-9

Table 7-6. Construction ESC BMP Design and Operation and Maintenance Costs as a 

Percentage of Capital Costs ............................................. 7-10

Table 7-7. Evaluated construction Site BMPs that Augment the Suite of 

Baseline BMPs ...................................................... 7-11

Table 7-8. BMP Quantity Adjustment Factors for Baseline and Proposed Options ........... 7-12

Table 7-9. National Cost Estimates for Proposed Rule Options .......................... 7-13

Table 7-10. One-Time Hours and Costs to Incorporate Erosion and Sediment Control 

Effluent Guidelines Requirements into General Permits ...................... 7-14

Figures

Figure 4-1. Annual Housing Starts .................................................. 4-8

Figure 4-2. Bureau of Census Housing Regions ...................................... 4-11

Figure 4-3. Annual Housing Starts by Region ........................................ 4-13

Figure 4-4. Value of Heavy construction work by region, 1997 .......................... 4-23

Figure 5-1. Flow Diagram Showing Relationship Among Goals, Strategies, Criteria, 

and Standards ......................................................... 5-9

Figure 7-1. EPA Ecoregions ....................................................... 7-3
Development Document for Construction and Development Proposed Effluent Guidelines 

June 2002 1-1

SECTION 1: OVERVIEW

1.1 INTRODUCTION

This document presents technical information to support the Agency’s analyses and complements

“Economic Analysis of Proposed Effluent Guidelines and Standards for the Construction and

Development Category,” EPA-821-R-02-008, and “Environmental Assessment for Proposed

Effluent Guidelines and Standards for the Construction and Development Category,” EPA 821-

R-02-009.

A summary of the information contained in the chapters of this document is as follows:

• Chapter 2 presents background information on the legal authority for effluent limitation

guidelines and the existing EPA storm water program.

• Chapter 3 presents a summary of the data collection activities conducted to support the

proposal.

• Chapter 4 summarizes the characteristics of the construction and development industry,

including major indicators of industry size and annual construction activity.

• Chapter 5 presents information and data on erosion and sediment control (ESC) best

management practices (BMPs) used by this industry, including applicability, costs, and

efficiencies.

• Chapter 6 presents a description of the regulatory options considered by EPA for

developing the proposal, as well as a walk-through of the provisions of each proposed

option.

• Chapter 7 presents the methodology used by the Agency to estimate the costs of the

proposed options.

1.2 SUMMARY AND SCOPE OF PROPOSAL

The proposed rule contains three options for controlling storm water discharges from

construction sites. 

• Option 1 would establish inspection and certification provisions to ensure proper

implementation of controls. This option would apply to all construction sites disturbing

one or more acres of land required to obtain a permit under the existing National

Pollutant Discharge Elimination System (NPDES) storm water regulations. This option
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June 2002 1-2

would amend the NPDES regulations at 40 CFR Part 122, but would not create effluent

limitation guidelines.

• Option 2 would add minimum requirements for preparation of a Storm Water Pollution

Prevention Plan (SWPPP) as well as minimum requirements for sizing sediment basins,

installing erosion and sediment controls, providing temporary stabilization to exposed

soils, and conducting regular inspections. Option 2 would apply to all sites that disturb

five or more acres of land, consistent with the permitting requirements of the Phase I

NPDES storm water regulations. This option would create a new effluent guidelines

category at 40 CFR Part 450 and would also modify 40 CFR Part 122. 

• Option 3 would not establish any new requirements.

EPA estimated that Option 1 would cost approximately $130 million annually, while preventing

the annual discharge of approximately 5.25 million tons of Total Suspended Solids (TSS) and

associated turbidity to surface waters. The estimated annual monetized benefits of this option are

$10.4 million. Option 2 is estimated to cost approximately $505 million annually, while

preventing the discharge of approximately 11.1 million tons of TSS and associated turbidity to

surface waters annually. The estimated annual monetized benefits of Option 2 are $22.0 million. 

Option 3 is not expected to have any costs or benefits.
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June 2002 2-1

SECTION 2: BACKGROUND

2.1 LEGAL AUTHORITY

The Environmental Protection Agency (EPA) is proposing Effluent Limitation Guidelines for

discharges associated with construction and development activities under the authority of

Sections 301, 304, 306, 308, 402, and 501 of the Clean Water Act (CWA) (the Federal Water

Pollution Control Act), 33 United States Code (U.S.C.) 1311, 1314, 1316, 1318, 1342, and 1361. 

This section describes EPA’s legal authority for issuing the regulation, existing state regulations,

and other federal regulations associated with construction and development activities.

2.2 CLEAN WATER ACT

Congress adopted the Clean Water Act (CWA) to "restore and maintain the chemical, physical,

and biological integrity of the nation's waters" (Section 101(a), 33 U.S.C. 1251(a)). To achieve

this goal, the CWA prohibits the discharge of pollutants into navigable waters except in

compliance with the statute. CWA sec. 402 requires "point source" discharges to obtain a permit

under the National Pollutant Discharge Elimination System (NPDES). These permits are issued

by EPA regional offices or authorized State agencies.

Following enactment of the Federal Water Pollution Control Amendments of 1972 (Pub.L. 92-

500, October 18, 1972), EPA and the States issued NPDES permits to thousands of dischargers,

both industrial (e.g. manufacturing, energy and mining facilities) and municipal (sewage

treatment plants). As required under Title III of the Act, EPA promulgated effluent limitation

guidelines and standards for many industrial categories, and these requirements are incorporated

into the permits.

The Water Quality Act of 1987 (Pub.L. 100-4, February 4, 1987) amended the CWA. The

NPDES program was expanded by defining municipal and industrial storm water discharges as

point sources. Industrial storm water dischargers, municipal separate storm sewer systems and

other storm water dischargers designated by EPA must obtain NPDES permits pursuant to

Section 402(p) (33 U.S.C. 1342(p)).
Development Document for Construction and Development Proposed Effluent Guidelines

 1 In the initial stages of EPA CWA regulation, EPA efforts emphasized the achievement of BPT limitations for

control of the "classical" pollutants (e.g., TSS, pH, BOD5). However, nothing on the face of the statute explicitly

restricted BPT limitation to such pollutants. Following passage of the Clean Water Act of 1977 (Pub.L. 95-217,

December 27, 1977) with its requirement for point sources to achieve best available technology limitations to control

discharges of toxic pollutants, EPA shifted its focus to developing BAT limitations for the listed priority toxic

pollutants.

June 2002 2-2

2.2.1 BEST PRACTICABLE CONTROL TECHNOLOGY CURRENTLY

AVAILABLE

In guidelines for a point source category, EPA may define BPT effluent limits for conventional,

toxic,1 and non-conventional pollutants. In specifying BPT, EPA looks at a number of factors. 

EPA first considers the cost of achieving effluent reductions in relation to the effluent reduction

benefits. The Agency also considers the age of the equipment and facilities, the processes

employed and any required process changes, engineering aspects of the control technologies,

non-water quality environmental impacts (including energy requirements), and such other factors

as the Agency deems appropriate (CWA sec. 304(b)(1)(B)). Traditionally, EPA establishes BPT

effluent limitations based on the average of the best performance of facilities within the category

of various ages, sizes, processes or other common characteristics. Where existing performance is

uniformly inadequate, EPA may require higher levels of control than currently in place in a

category if the Agency determines that the technology can be practically applied. (US Senate,

1973, p. 1468).

In addition, the Act requires a cost-reasonableness assessment for BPT limitations. In

determining the BPT limits, EPA considers the total cost of treatment technologies in relation to

the effluent reduction benefits achieved. This inquiry does not limit EPA's broad discretion to

adopt BPT limitations that are achievable with available technology unless the required

additional reductions are "wholly out of proportion to the costs of achieving such marginal level

of reduction." (US Senate, 1973, p. 170) Moreover, the inquiry does not require the Agency to

quantify benefits in monetary terms. See, for example, American Iron and Steel Institute v. EPA,

526 F. 2d 1027 (3rd Cir., 1975).

In balancing costs against the benefits of effluent reduction, EPA considers the volume and

nature of expected discharges after application of BPT, the general environmental effects of

pollutants, and the cost and economic impacts of the required level of pollution control. In past

effluent limitation guidelines and standards, BPT cost-reasonableness removal figures have

ranged from $0.21 to $33.71 per pound removed in year 2000 dollars. In developing guidelines,

the Act does not require consideration of water quality problems attributable to particular point

sources, or water quality improvements in particular bodies of water. Accordingly, EPA has not

considered these factors in developing the limitations being proposed today. See Weyerhaeuser

Company v. Costle, 590 F. 2d 1011 (D.C. Cir. 1978).
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June 2002 2-3

2.2.2 BEST CONVENTIONAL POLLUTANT CONTROL TECHNOLOGY

The 1977 amendments to the CWA required EPA to identify effluent reduction levels for

conventional pollutants associated with BCT technology for discharges from existing point

sources. BCT is not an additional limitation, but replaces Best Available Technology (BAT) for

control of conventional pollutants. In addition to other factors specified in sec. 304(b)(4)(B), the

CWA requires that EPA establish BCT limitations after consideration of a two- part "costreasonableness" test. EPA explained its methodology for the development of BCT limitations in

July 1986 (51 FR 24974).

Section 304(a)(4) designates the following as conventional pollutants: biochemical oxygen

demand (BOD5), total suspended solids (TSS), fecal coliform, pH, and any additional pollutants

defined by the Administrator as conventional. The Administrator designated oil and grease as an

additional conventional pollutant on July 30, 1979 (44 FR 44501). A primary pollutant of

concern at construction sites, sediment, is measured as TSS.

2.2.3 BEST AVAILABLE TECHNOLOGY ECONOMICALLY ACHIEVABLE

In general, BAT effluent guidelines (CWA sec. 304(b)(2)) represent the best existing

economically achievable performance of direct discharging plants in the subcategory or category. 

The factors considered in assessing BAT include the cost of achieving BAT effluent reductions,

the age of equipment and facilities involved, the processes employed, engineering aspects of the

control technology, potential process changes, non-water quality environmental impacts

(including energy requirements), and such factors as the Administrator deems appropriate. The

Agency retains considerable discretion in assigning the weight to be accorded to these factors. 

An additional statutory factor considered in setting BAT is "economic achievability." Generally,

EPA determines the economic achievability on the basis of the total cost to the subcategory and

the overall effect of the rule on the industry's financial health. The Agency may base BAT

limitations upon effluent reductions attainable through changes in a facility's processes and

operations. As with BPT, where existing performance is uniformly inadequate, EPA may base

BAT upon technology transferred from a different subcategory or from another category. In

addition, the Agency may base BAT upon manufacturing process changes or internal controls,

even when these technologies are not common industry practice.

2.2.4 NEW SOURCE PERFORMANCE STANDARDS

New Source Performance Standards (NSPS) reflect effluent reductions that are achievable based

on the best available demonstrated control technology. New facilities have the opportunity to

install the best and most efficient production processes and wastewater treatment technologies. 

As a result, NSPS should represent the greatest degree of effluent reduction attainable through

the application of the best available demonstrated control technology for all pollutants (i.e.,

conventional, non-conventional, and priority pollutants). In establishing NSPS, CWA sec. 306
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June 2002 2-4

directs EPA to take into consideration the cost of achieving the effluent reduction and any nonwater quality environmental impacts and energy requirements.

2.2.5 PRETREATMENT STANDARDS FOR EXISTING SOURCES AND

PRETREATMENT STANDARDS FOR NEW SOURCES

The CWA also defines standards for indirect discharges, i.e. discharges into publicly owned

treatment works (POTWs). These are Pretreatment Standards for Existing Sources (PSES) and

Pretreatment Standards for New Sources (PSNS) under sec. 307(b). Because EPA has identified

no deliberate discharges directly to POTWs, EPA is not proposing PSES or PSNS for the

Construction and Development Category. The information reviewed by the Agency indicates

that the vast majority of construction sites discharge either directly to waters of the U.S. or

through MS4s. In some urban areas, construction sites discharge to combined sewer systems

(i.e., sewers carrying both storm water and domestic sewage through a single pipe) which lead to

POTWs. Sediment is susceptible to treatment in POTWs, using technologies commonly

employed such as primary clarification, and EPA has no evidence of interference, pollutant passthrough or sludge contamination.

2.2.6 EFFLUENT GUIDELINES SCHEDULE

Clean Water Act section 304(m) requires EPA to publish a plan every two years that consists of

three elements. First, under sec. 304(m)(1)(A), EPA is required to establish a schedule for the

annual review and revision of existing effluent guidelines in accordance with sec. 304(b). 

Section 304(b) applies to ELGs for direct dischargers and requires EPA to revise such regulations

as appropriate. Second, under sec. 304(m)(1)(B), EPA must identify categories of sources

discharging toxic or nonconventional pollutants for which EPA has not published BAT ELGs

under sec. 304(b)(2) or new source performance standards under sec. 306. Finally, under sec.

304(m)(1)(C), EPA must establish a schedule for the promulgation of BAT and NSPS for the

categories identified under subparagraph (B) not later than three years after being identified in the

304(m) plan. Section 304(m) does not apply to pretreatment standards for indirect dischargers,

which EPA promulgates pursuant to sec. 307(b) and 307(c) of the Act.

On October 30, 1989, Natural Resources Defense Council, Inc. (NRDC), and Public Citizen,

Inc., filed an action against EPA in which they alleged, among other things, that EPA had failed

to comply with sec. 304(m). Plaintiffs and EPA agreed to a settlement of that action in a consent

decree entered on January 31, 1992. (Natural Resources Defense Council et al v. Whitman,

D.D.C. Civil Action No. 89-2980). The consent decree, which has been modified several times,

established a schedule by which EPA is to propose and take final action for eleven point source

categories identified by name in the decree and for eight other point source categories identified

only as new or revised rules, numbered 5 through 12. EPA selected the Construction and

Development category as the subject for New or Revised Rule #10. The decree, as modified,

calls for the Administrator to sign a proposed ELG for the C&D category no later than May 15,
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June 2002 2-5

2002, and to take final action on that proposal no later than March 31, 2004. A settlement

agreement between the parties, signed on June 28, 2000, requires that EPA develop regulatory

options applicable to discharges from construction, development and redevelopment, covering

site sizes included in the Phase I and Phase II NPDES storm water rules (i.e. one acre or greater). 

EPA is required to develop options including numeric effluent limitations for sedimentation and

turbidity; control of construction site pollutants other than sedimentation and turbidity (e.g.

discarded building materials, concrete truck washout, trash); BMPs for controlling postconstruction runoff; BMPs for construction sites; and requirements to design storm water

controls to maintain pre-development runoff conditions where practicable. The settlement also

requires EPA to issue guidance to MS4s and other permittees on maintenance of postconstruction BMPs identified in the proposed ELGs. Further discussion of approaches not

pursued by EPA at this time may be found in the docket for today's proposal.

2.2.7 NPDES PHASE I AND II STORM WATER RULES

The National Pollutant Discharge Elimination System (NPDES) is a permit system established

under the CWA to enforce effluent limitation. Operators of construction activities, including

clearing, grading and excavation are required to apply for permit coverage under the NPDES

Phase I and II storm water rules. Under the Phase I rule (promulgated in 1990), construction sites

of 5 or more acres must be covered by either a general or an individual permit. General permits

covering the Phase I sites have been issued by EPA regional offices and state water quality

agencies. Permittees are required to develop storm water pollution prevention plans that include

descriptions of BMPs employed, although actual BMP selection and design are at the discretion

of permittees (in conformance with applicable state or local requirements).

Construction sites between 1 and 5 acres in size are subject to the NPDES Phase II storm water

rule (promulgated in 1999). The construction activities covered under Phase II are termed small

construction activities and exclude routine maintenance that is performed to maintain the original

line and grade, hydraulic capacity, or original purpose of the facility. Under the Phase II program,

NPDES permit requirements for construction activities are similar to the Phase I requirements

because they will be covered under similar general permits.

2.3 POLLUTION PREVENTION ACT OF 1990

The Pollution Prevention Act of 1990 (PPA) (42 U.S.C. 13101 et seq., Pub. L. 101-508,

November 5, 1990) makes pollution prevention the national policy of the United States. The

PPA identifies an environmental management hierarchy in which pollution "should be prevented

or reduced whenever feasible; pollution that cannot be prevented should be recycled in an

environmentally safe manner, whenever feasible; pollution that cannot be prevented or recycled

should be treated in an environmentally safe manner whenever feasible; and disposal or release

into the environment should be employed only as a last resort..." (42 U.S.C. 13103). In short,

preventing pollution before it is created is preferable to trying to manage, treat or dispose of it
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June 2002 2-6

after it is created. According to the PPA, source reduction reduces the generation and release of

hazardous substances, pollutants, wastes, contaminants or residuals at the source, usually within

a process. The term source reduction "...includes equipment or technology modifications,

process or procedure modifications, reformulation or redesign of products, substitution of raw

materials, and improvements in housekeeping, maintenance, training, or inventory control. The

term 'source reduction' does not include any practice which alters the physical, chemical, or

biological characteristics or the volume of a hazardous substance, pollutant, or contaminant

through a process or activity which itself is not integral to or necessary for the production of a

product or the providing of a service." In effect, source reduction means reducing the amount of

a pollutant that enters a waste stream or that is otherwise released into the environment prior to

out-of-process recycling, treatment, or disposal.

Although the PPA does not explicitly address storm water discharges or discharges from

construction sites, the principles of the PPA are implicit in many of the practices used to reduce

pollutant discharges from construction sites. These include controls that minimize the potential

for erosion such as stabilization of disturbed areas as soon as practicable. These controls are

described in section 5 of the Development Document.

2.4 STATE REGULATIONS

States and municipalities have been regulating discharges of runoff from construction and land

development industry to varying degrees for some time. A compilation of state and selected

municipal regulatory approaches was prepared to help establish the baseline for national and

regional levels of control. Data were collected by reviewing state and municipal web sites,

summary references, state and municipal regulations and storm water guidance manuals. All

states (and the selected municipalities) were contacted to confirm the data collected and to fill in

data gaps, however, only 87 percent of the state agencies and a much smaller percentage of

municipalities responded. The state and municipal regulatory data are summarized in Section 3.3

and the complete data sheets are included in Appendix A.

2.5 REFERENCES

US Senate, 1973. A Legislative History of the Federal Water Pollution Control Act Amendments

of 1972. U.S. Senate Committee of Public Works, Serial No. 93-1, January 1973. 

Washington, DC.
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SECTION 3: DATA COLLECTION

3.1 INTRODUCTION

EPA gathered and evaluated technical and economic data from various sources in the course of

developing the effluent limitation guidelines and standards for the construction and development

industry. EPA used existing data sources to profile the industry with respect to general industry

description, industry trends, environmental impacts, and erosion and sediment control best

management practices (BMPs) and cost. This chapter details the data sources used in the

development of this proposal.

3.2 LITERATURE SEARCH

A literature search was performed to obtain information on various BMPs that pertain to the

construction and land development industry. Journal articles and professional conference

proceedings were used to summarize the most recent BMP effectiveness data, design and

installation criteria, applicability, advantages, limitations, and cost. 

3.3 COMPILATION OF STATE AND MUNICIPAL EXISTING CONTROL

STRATEGIES, CRITERIA, AND STANDARDS

A compilation of State and municipal regulations were prepared to determine national and

regional approaches towards controlling construction site storm water. The data were collected

by reviewing State and municipal web sites, summary references, and State and municipal

regulations and storm water guidance manuals. States and municipalities were contacted to

confirm the data collected and to fill in data not available by these methods. Not all State and

municipal contacts responded or were able to provide the missing information sought. While 87

percent of the State agencies provided confirmation of the regulatory data collected for this study,

a much smaller percentage of municipalities responded.

A summary of criteria and standards that are implemented by States and municipalities as of

August 2000 are presented in Tables 3-1 and 3-2, respectively. State requirements are generally

equal to or less stringent than municipalities that are covered under the federal Clean Water Act

NPDES Storm Water Program because State requirements apply to all development within their

boundaries including single site development and low to high density developments. NPDES

Storm Water Program designated municipalities generally have a population of 100,000 or more

and can collect and fund the resources necessary to design, implement, and monitor separate and

potentially more stringent storm water management programs. Table 3-1 contains responses

from 47 of the 54 State controlling agencies. The total is greater than 50 because Florida has 5

intrastate regional authorities. Some State data were uncertain and repeated contacts to the

responsible State agencies to confirm the data were not returned. For the same reason, some of
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June 2002 3-2

the data sought from municipal agencies also are not available for this report. Tables 3-1 and 3-2

are summaries of the regulatory controls used by States and municipalities as presented on Table

A-1: State regulations on the control of construction phase storm water.

Many data were not readily available. Appendix A presents Tables A-1which includes all of the

data that was collected.

The data collected reflect a cross section of the US geography but are representative primarily of

municipalities that have a population of 100,000 or greater and relatively few municipalities of

smaller population. Thirty-one municipalities are included in the summary tables, which is a

relatively small data set compared to the approximately 240 municipalities with NPDES

programs and nearly 3,000 municipalities nationwide. Therefore, the data presented for the

States in Table 3-1 is fairly comprehensive while data for the municipalities presented in Table 3-

2 is not comprehensive but does reflect the diversity of management techniques used at the

municipal level.
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Table 3-1. State or Regional Planning Authority Requirements

for Water Quality Protection

Standard

Number of

States with

Requirementa

Percent of

National

Developed

Acreage with

Requirement

Percent of

National

Developed

Acreage

without

Requirement 

Percent of

National

Developed

Acreage

without

Information 

Solids or sediment

percent reduction 11 24% 61% 15%

Numeric effluent limits

for TSS, settleable

solids, or turbidity

2 11% 76% 13%

Numeric design depth or

volume for water quality

treatment

22 53% 28% 19%

Habitat/biological

measures

3 7% 80% 13%

Physical in-stream

condition controls 8 17% 70% 13%

Water Quality or

Effluent Monitoring

Requirement

3 6% 83% 11%

a

 Florida has 5 Water Management Districts. If any of these Districts met a particular standard, the

entire state annual developed acreage was counted.
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Table 3-2. Municipal Planning Authority Requirements

Standard

Percent of

Municipalities

Reviewed with

Requirement 

Percent of

Municipalities

Reviewed without

Requirement 

Percent of

Municipalities

without

Information 

Design storm for peak

discharge control 39% 45% 16%

Solids or sediment

percent reduction 7% 77% 16%

Numeric design depth,

storm, or volume for

water quality treatment

– – –

Design storm for flood

control 39% 16% 23%

Habitat/biological

measures

3% 65% 32%

Physical in-stream

condition controls 10% 58% 32%

Note: This table reflects data collected from 31 municipalities

Tables 3-1 and 3-2 indicate that the following key control measures are being employed by States

and municipal/regional authorities to implement the NPDES Storm Water Program:

• Storm water controls designed for peak discharge control

• Storm water controls designed for water quality control

• Storm water controls designed for flood control

• Specified depths of runoff for water quality control

• Percent reduction of loadings for water quality control (primarily solids and sediments)

• Numeric effluent limits for water quality control (primarily total suspended solids, settleable

solids, or turbidity)

• Control measures for biological or habitat protection

• Control measures for physical in-stream condition controls (primarily streambed and

streambank erosion).

The water quantity control measures for peak discharge and runoff volume controls that apply to

the post-development conditions typically are not applicable during the construction phase when

the site is disturbed. Pollutant control measures are commonly required during the construction

phase, though the requirements for post-development storm water management are broader and

potentially more stringent.
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3.4 OTHER DATA SOURCES

3.4.1 PHASE II STORM WATER RULE ECONOMIC ANALYSIS

The Economic Analysis of the Final Phase II Storm Water Rule (USEPA, 1999) estimated Phase

II Storm Water Rule compliance costs for two major categories of pollutant controls for

construction sites: erosion and sediment control BMPs and post-construction storm water

management controls. Total costs for implementing the Phase II Rule encompass expenditures

for installation of erosion and sediment control technologies, labor requirements for submitting a

Notice of Intent (NOI) to be covered by a general permit, a Notification to Municipalities, a

Storm Water Pollution Prevention Plan (SWPPP), and maintenance costs. Costs were derived on

a per-site basis and then aggregated to the State and national level based on the number of

building permits issued. As described in the Economic Analysis Report for the Phase II Rule,

census data were used to project the annual number of construction permits by Standard

Industrial Classification (SIC) Code and construction permit data from 14 municipalities were

used to categorize construction activities by site size. 

3.4.2 1997 USDA NATIONAL RESOURCE INVENTORY

The 1997 National Resources Inventory (NRI) (USDA, 2000) is a statistically based survey that

has been designed and implemented to assess conditions and trends of soil, water, and related

resources on non-Federal lands in the United States. The NRI is conducted every 5 years by the

U.S. Department of Agriculture's (USDA) Natural Resources Conservation Service (NRCS), in

cooperation with the Iowa State University Statistical Laboratory. The inventory provides

scientifically valid, timely, and relevant information that is used to formulate effective

agricultural and environmental policies and legislation, implement resource conservation

programs, and enhance the public's understanding of natural resources and environmental

conditions.

The NRI is a compilation of natural resource information on non-Federal land in the United

States–nearly 75 percent of the country’s land base. The inventory captures data on land cover

and use, soil erosion, prime farmland, wetlands, habitat diversity, selected conservation practices,

and related resource attributes at more than 800,000 scientifically selected sample sites. The NRI

can be accessed at http://www.nrcs.usda.gov/technical/NRI/.

3.4.3 NATIONAL STORM WATER BMP DATABASE

The National Stormwater BMP Database, developed by the American Society of Civil Engineers

(ASCE), is designed to be a source of reliable data to help improve water quality nationwide by

sharing consistent and transferable information on the performance of storm water best

management practices. The database helps water quality professionals across the United States

learn about successful BMPs and apply proven methods to local water quality projects. The
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June 2002 3-6

database is based on extensive screening of a bibliography of more than 800 existing BMP

studies and was designed by national storm water experts on ASCE's Urban Water Resources

Research Council. As of June 2002, the database contains data on 198 BMPs. Representative

information provided for BMPs includes test site location, researcher contact data, watershed

characteristics, regional climate statistics, BMP design parameters, monitoring equipment types,

and monitoring data such as precipitation, flow, and water quality. The database can be accessed

online at http://www.bmpdatabase.org.

3.4.4 BMP DESIGN MANUALS AND GUIDANCE DOCUMENTS DEVELOPED

BY GOVERNMENTAL AND OTHER ORGANIZATIONS

A variety of manuals and documents were used to obtain information on design and effectiveness

of various BMPs. Examples include: (1) State design manuals such as the Virginia Erosion and

Sediment Control Handbook (http://www.dcr.state.va.us/sw/e&s-ftp.htm), the Maryland Storm

Water Design Manual (http://www.mde.state.md.us/environment/wma/stormwatermanual), and

the Denver Urban Drainage Criteria Manual (http://www.udfcd.org); (2) Guidance documents 

such as the Texas Nonpoint Source Book http://www.txnpsbook.org) and EPA's National Menu

of BMPs (http://www.epa.gov/npdes/menuofbmps/menu.htm); and (3) Consensus design

manuals such as manuals of practice on storm water design developed by ASCE and the Water

Environment Federation (ASCE and WEF, 1992 and1998) were used to determine various

management strategies. Links to on-line manuals and guidance documents are provided on

EPA's website at http://www.epa.gov/waterscience/guide/construction/ .

3.5 REFERENCES

ASCE and WEF. 1992. Design and Construction of Urban Stormwater Management Systems.

ASCE Manual and Report on Engineering Practice No. 77; WEF Manual of Practice No.

FD-20. American Society of Civil Engineers, New York, NY. Water Environment

Federation, Alexandria, VA. http://www.asce.org and http://www.wef.org .

ASCE and WEF. 1998. Urban Runoff Quality Management. ASCE Manual and Report on

Engineering Practice No. 87; WEF Manual of Practice No. 23. American Society of Civil

Engineers, Reston, VA. Water Environment Federation, Alexandria, VA. 

http://www.asce.org and http://www.wef.org .

USEPA. 1999. Economic Analysis of the Final Phase II Storm Water Rule. U.S. Environmental

Protection Agency, Office of Wastewater Management. Washington, DC.

USDA. 2000. 1997 National Resources Inventory. U.S. Department of Agriculture, National

Resources Conservation Service, Washington, DC. 

http://www.nrcs.usda.gov/technical/NRI/.
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June 2002 4-1

SECTION 4: INDUSTRY PROFILE

4.1 INTRODUCTION

The construction sector is among the largest and most important sectors in the national 

economy, accounting for approximately 4 percent of the U.S. gross domestic product. During

1997, approximately 262,000 construction companies with payroll in the United States employed

nearly 2.4 million workers nationwide. Another 1.6 million workers associated with construction

activities were self-employed. The construction industry is divided into three major subsectors:

general building contractors, heavy construction contractors, and special trade contractors. 

General contractors build residential, industrial, commercial, and other buildings. Heavy

construction contractors build sewers, roads, highways, bridges, and tunnels. Special trade

contractors typically provide carpentry, painting, plumbing, and electrical services. 

Because the proposed effluent guidelines are being developed to address water quality issues,

this document focuses on the construction subsectors most closely associated with landdisturbing activities. General contractors and heavy construction establishments are by definition

the most likely to conduct activities that could affect water resources. It should be noted,

however, that for individual projects responsibility for land-disturbing activities and potential

impacts on water quality might not be obvious because general contractors often subcontract all

or some of the actual construction work. Hence, the following subsections describe the subsector

categories most likely to be responsible for land-disturbing activities at the national level.

4.2 INDUSTRY DESCRIPTION

4.2.1 INDUSTRY DEFINITION AND CLASSIFICATION OF SUBSECTORS BY NAIC

AND SIC CODES

The construction and land development industry is classified in the 1997 North American

Industry Classification System (NAICS, 1997) under Sector 23, Construction. NAICS 1997 is

the system currently used for classifying industry establishments by type of economic activity. It

replaced the U.S. Standard Industrial Classification (SIC) system. 

Construction work includes new construction, additions, alterations, and repairs. Establishments

identified as construction-management firms are also included. The construction sector is divided

into three types of activities or subsectors:

• Subsector 233–Building, Developing, and General Contracting 

This subsector is made up of establishments responsible for the construction of building

projects. Builders, developers, and general contractors, as well as land subdividers and

land developers, are included in the subsector. The construction work may be done for
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June 2002 4-2

others and performed by custom builders, general contractors, design builders, or turnkey

contractors. This construction activity may be for sale as performed by speculative or

operative builders. 

• Subsector 234–Heavy Construction 

This subsector comprises establishments engaged in the construction of heavy

engineering and industrial projects (except buildings), such as highways, power plants,

and pipelines. Establishments in this subsector usually assume responsibility for entire

nonbuilding projects, but they may hire subcontractors for some or all of the actual

construction work. Special trade contractors are included in this group if they are

engaged in activities primarily related to heavy construction, such as grading for

highways. The kinds of establishments in this group include heavy-construction general

contractors and design builders.

• Subsector 235–Special Trade Contractors 

This subsector comprises establishments engaged in specialized construction activities,

such as plumbing, painting, and electrical work. The activities in this subsector may be

subcontracted from builders or general contractors, or the work may be performed

directly for project owners. Special trade contractors usually perform most of their work

at the job site.

Table 4-1 provides a list of the 3-digit subsectors, 4-digit industry groups and 5-digit NAICS

industries in the construction sector.
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Table 4-1. 1997 NAICS Subsectors, Industry Groups,

and Industries Performing Construction Activities

That Might Disturb Land

1997 NAICS Sector 23 - Construction 

233 Building, Developing, and General Contracting

2331 Land Subdivision and Land Development

23311 Land Subdivision and Land Development

2332 Residential Building Construction

23321

23322

Single-family Housing Construction

Multifamily Housing Construction

2333 Nonresidential Building Construction

23331

23332

Manufacturing and Industrial Building Construction

Commercial and Institutional Building Construction

234 Heavy Construction

2341 Highway, Street, Bridge, and Tunnel Construction

23411

23412

Highway and Street Construction

Bridge and Tunnel Construction

2349 Other Heavy Construction

23491

23492

23493

23499

Water, Sewer, and Pipeline Construction

Power and Communication Transmission Line Construction

Industrial Nonbuilding Structure Construction

All Other Heavy Construction

235 Special Trade Contractors

2357 Concrete Contractors

23571 Concrete Contractors

2359 Other Special Trade Contractors

23593 Excavation Contractors

Before the creation of the NAICS, construction and land development industries were classified

using the SIC system. Any data collected before January 1997 might still be classified under that

system. SIC classifications are relevant to the effluent guidelines, because certain U.S. Bureau of

the Census (BOC) data for the construction industry were collected until 1994 and therefore

classified under the SIC system rather than the NAICS. Under the SIC system, industries that

might perform land-disturbing activities were classified under Division C–Construction, and
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June 2002 4-4

Division H–Finance, Insurance, and Real Estate. These divisions include the following SIC

major groups:

• SIC Major Group 15–Building Construction General Contractors and Operative Builders

This group includes general contractors and operative builders primarily engaged in the

construction of residential, farm, commercial, or other buildings. General building

contractors who combine a special trade with their contracting are also included.

• SIC Major Group 16–Heavy Construction Other Than Building Construction Contractors

This group includes general contractors primarily engaged in heavy construction other

than building construction, such as highways and streets, bridges, sewers, railroads,

irrigation projects, flood control projects, and marine construction, as well as special

trade contractors primarily engaged in activities of a type clearly specialized in such

heavy construction and not normally performed on buildings or building-related projects.

• SIC Major Group 17–Construction Special Trade Contractors

This group includes special trade contractors who undertake activities of a type that are

specialized either in building construction or in both building and nonbuilding projects.

• SIC Major Group 65–Real Estate

This group includes real estate operators and the owners and lessors of real property, as

well as buyers, sellers, developers, agents, and brokers.

Major groups 15 and 16 are further defined by the type of construction performed. Table 4-2

provides a list of the more specific industry groups and industries that might perform landdisturbing activities.
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June 2002 4-5

Table 4-2. 1987 SIC Industry Groups Performing Construction

Activities That May Disturb Land

SIC Major Group 15

Industry Group 152: General Building Contractors - Residential

1521 General Contractors - Single-family Houses

1522 General Contractors - Residential Buildings, Other Than Single-family

Industry Group 153: Operative Builders

1531 Operative Builders

Industry Group 154: General Building Contractors - Nonresidential

1541 General Contractors - Industrial Buildings and Warehouses

1542 General Contractors - Nonresidential Buildings, Other Than Industrial

SIC Major Group 16

Industry Group 161: Highway and Street Construction, Except Elevated Highways

1611 Highway and Street Construction, Except Elevated Highways

Industry Group 162: Heavy Construction, Except Highway and Street

1622 Bridge, Tunnel, and Elevated Highway Construction

1623 Water, Sewer, Pipeline, and Communications and Power Line

1629 Heavy Construction Not Elsewhere Classified

SIC Major Group 17

Industry Group 179: Miscellaneous Special Trade Contractors

1771 Concrete Work

1794 Excavation Work

SIC Major Group 65

Industry Group 655: Land Subdividers and Developers

6552 Land Subdividers and Developers, Except Cemeteries

The focus of this Development Document is on construction activities carried out by firms

covered by NAICS codes 233 and 234 or SIC codes 15 and 16. (As discussed in Section VI.A in

the preamble of the proposed rule, Special Trade Contractors, NAICS 235 or SIC 17, are

typically subcontractors and not identified as NPDES permittees.) Furthermore, the residential,
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June 2002 4-6

non-residential, and heavy construction subsectors receive the greatest emphasis, because they

account for the vast majority of construction projects and are responsible for most of the land

disturbance in the United States. The following subsections describe these subsectors in terms of

size, distribution, and recent growth trends.

4.2.2 RESIDENTIAL BUILDING CONSTRUCTION GROUP

Residential Construction Industry Description. The U.S. Bureau of the Census (BOC), a

division of the Department of Commerce (DOC), divides the residential construction industry

into two categories. The first encompasses single-family housing construction and includes

mobile homes, prefabricated houses, row houses, town houses, and single-family detached

houses. The second encompasses multifamily housing construction and includes high-rise

apartments, garden apartments, and town house apartments in which units are not separated by

ground-to-roof walls.

Historic Trends. The DOC began collecting detailed information on housing starts in 1963. 

Data on housing permits and starts are published monthly by the DOC and are viewed by

economists as leading indicators of economic activity. More detailed industry information is

collected through the Census of Construction Industries (CCI), which is conducted every 5 years

(in years ending in a 2 or a 7) as part of the Census Bureau's Economic Census program. These

data provide the most detailed snapshot of the status of the construction industry. The CCI

covers all employer establishments primarily engaged in construction as defined by the NAICS

and includes nonresidential construction activities. Table 4-3 summarizes housing starts for the

period from 1979 to 1999.

In Table 4-3, the number of construction starts is shown by regional location and type of

structure. The table also provides national totals for both single- and multifamily housing starts

(BOC, 2001). As shown in the table, single-family housing starts account for the majority of

housing construction starts. Figure 4-1 combines single- and multifamily housing starts and

graphically depicts annual changes during the 1997-1999 period. The number of construction

starts for privately owned housing units has decreased from approximately 1.7 million starts in

1979 to roughly 1.6 million starts in 1999 (BOC, 2001).
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Table 4-3. Annual Housing Construction Starts by Type and Region

(Starts are in thousands)

Year United

States

Northeast Midwest South West

SinglefamilyMultifamilySinglefamily MultifamilySinglefamilyMultifamilySinglefamilyMultifamily

1979 1,745 123 55 243 106 522 225 306 165

1980 1,292 87 38 142 76 428 215 196 110

1981 1,084 84 33 110 55 363 198 148 92

1982 1,062 79 37 99 50 357 234 127 78

1983 1,703 123 45 153 65 557 378 234 148

1984 1,750 158 46 167 76 528 338 230 206

1985 1,742 182 70 148 92 504 278 239 230

1986 1,805 228 66 188 108 504 229 261 222

1987 1,621 204 65 203 95 485 149 255 165

1988 1,488 181 54 194 80 443 132 264 140

1989 1,376 132 47 190 76 409 127 272 124

1990 1,193 104 27 193 60 371 108 226 103

1991 1,014 99 14 191 42 353 62 197 57

1992 1,200 112 15 236 52 439 58 244 45

1993 1,288 116 11 251 47 498 63 261 41

1994 1,457 123 16 268 61 522 117 286 65

1995 1,354 102 16 233 57 485 130 256 76

1996 1,447 112 20 254 68 524 138 271 90

1997 1,474 111 26 238 66 507 164 278 86

1998 1,617 122 26 223 58 573 169 303 92

1999 1,641 126 29 289 59 580 167 308 84

Source: BOC, 2001.
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0

200

400

600

800

1,000

1,200

1,400

1,600

1,800

2,000

1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999

Year

Annual Housing Starts (thousands)

Figure 4-1. Annual Housing Starts

Housing start data tend to reflect the health of the U.S. economy. Therefore, as shown in Figure

4-1, the number of housing starts dropped significantly from 1986 to 1991 as the national

economy fell into a recession. Conversely, the robust economy over the past several years has

been accompanied by a strong growth in housing starts.

Industry Size. As a result of the recent strong growth in demand for new housing, the number of

workers employed in residential construction has also increased. According to the BOC (1999b),

the total number of employees in the housing construction industry rose from 452,257 in 1992 to

628,886 in 1997, an increase of almost 40 percent. Table 4-4 shows the number of workers

employed, the payroll for those workers, and the value of completed construction for 1997. As

shown in the table, the number of establishments and workers associated with construction of

single-family housing greatly exceeds that for multifamily housing construction. It should also

be noted that although construction of single-family homes is performed by both small and large

firms, most multifamily housing construction is performed by large firms. Specifically, a special

study by the Census Bureau (BOC, 2000a) found that about 39 percent of single-family homes

are built by small builders (fewer than 25 units in the year); 21 percent by medium builders (25-

99 units); and 40 percent by large builders (more than 100 units). In contrast, construction of

multifamily housing is performed primarily by larger builders. During 1997, large builders

constructed 77 percent of multifamily housing units.

The value of construction is defined as work done by general contractors, heavy construction

contractors, and special trade contractors. Included in these estimates are new construction,
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1

 Permits issued do not necessarily translate into housing starts, since a permit issued in

one year may not lead to actual construction until the next year. Furthermore, some permits

issued never lead to actual construction. Nonetheless, permit counts can serve as a good

indicator of construction activity in the near future.

June 2002 4-9

additions, alterations or reconstruction, and maintenance and repair; the costs of industrial and

other special equipment not an integral part of a structure are excluded. According to the 1997

Construction Census, the value of completed construction exceeded $161 billion. Single-family

housing construction accounted for almost $147 billion, or more than 90 percent of the total.

Table 4-4. Residential Construction Industry Profile for 1997

Single-Family Housing

Construction

Multifamily Housing

Construction

Total number of employees 570,990 58,896

Number of construction

establishments during the

year

138,849 7,543

Payroll (thousands) $14,964,583 $1,794,143

Value of construction

completed nationwide $146,798,768 $14,487,308

State with the highest dollar

value of construction work

for establishments with

payroll

California

($18,137,680)

Florida

($2,403,233)

Source: BOC, 1999b, 1999c.

Single-Family Housing Construction Trends. As noted earlier, housing construction starts

increased significantly during the second half of the 1990s. In 1999, single-family home

construction starts totaled more than 1.3 million, a level not reached since 1978 (BOC 2001). 

As indicated in Table 4-5 by the number of permits issued, Atlanta, Georgia, led all U.S. major

markets for single-family housing construction activity in 19991. The other leading market areas 

for single-family construction were Phoenix, Arizona; Dallas-Ft. Worth, Texas; Chicago,

Illinois; and Washington, D.C. Table 4-5 also shows the percent change in construction permits

issued from 1998 to 1999 (U.S. Housing Markets, 1999a).

Multifamily Housing Construction Trends. Construction of structures with multiple housing

units also increased significantly during the 1990s. For example, construction starts of these
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June 2002 4-10

buildings increased from about 173,500 in 1991 to more than 338,500 in 1999, an increase of

about 95 percent.

Table 4-5. Busiest Markets for Single-Family

Housing Permits for 1999

Market Area Single-family Housing

Permits (1999)

Percent Change

From 1998

Atlanta 25,066 +11%

Phoenix 21,290 +13%

Dallas-Ft. Worth 17,434 +6%

Chicago 14,954 +7%

Washington, DC 14,703 0.07

Source: U.S. Housing Markets, 1999a.

Much of the growth in multifamily housing was in the construction of facilities with more than

five units. According to U.S. Housing Markets (1999b), the top five busiest markets for

multifamily construction permits for 1999 were Dallas-Ft. Worth, Texas; Orlando, Florida; New

York-Long Island; Puget Sound, Washington; and Houston, Texas. Table 4-6 shows the number

of multifamily permits and the percent change in permits issued from 1998 to 1999.

Regional Housing Start Trends (Single-family and Multifamily Structures). The Census Bureau

estimates housing starts at the regional level through statistical analysis of its survey data.

Table 4-6. Busiest Markets for Multifamily

Housing Permits for 1999

Market Area Multifamily Housing 

Permits (1999)

Percent Change

From 1998

Dallas-Ft. Worth 8,488 -15%

Orlando 7,303 +46%

New York-Long Island 6,255 +55%

Puget Sound 6,122 +19%

Houston 5,900 -50%

Source: U.S. Housing Markets, 1999b.
Development Document for Construction and Development Proposed Effluent Guidelines

2

The Northeast includes the following states: Connecticut, Maine, Massachusetts, New Hampshire, New Jersey, New

York, Pennsylvania, Rhode Island, and Vermont.

3

The Midwest includes the following states: Illinois, Indiana, Iowa, Kansas, Michigan, Minnesota, Missouri, Nebraska,

North Dakota, Ohio, South Dakota, and Wisconsin.

4

The South includes the following states: Alabama, Arkansas, Delaware, District of Columbia, Florida, Georgia,

Kentucky, Louisiana, Maryland, Mississippi, North Carolina, Oklahoma, South Carolina, Tennessee, Texas, Virginia, and West

Virginia.

5

The West includes the following states: Alaska, Arizona, California, Colorado, Hawaii, Idaho, Montana, Nevada,

New Mexico, Oregon, Utah, Washington, and Wyoming. 

June 2002 4-11

Figure 4-2. Bureau of Census Housing Regions

As shown in Figure 4-2, the Census Bureau divides the United States into four regions:

Northeast2

, Midwest 3, South4, and West5. Table 4-7 summarizes changes in construction starts

at the regional level for the years 1989 and 1999.

As noted earlier, national housing starts have increased significantly over the past decade. At the

regional level, however, growth rates have varied to a large degree. As shown in Figure 4-3 and
Development Document for Construction and Development Proposed Effluent Guidelines

June 2002 4-12

summarized in Table 4-7, construction of housing increased by nearly 40 percent in the South,

whereas construction starts in the Northeast actually decreased by almost 13 percent 

from 1989 levels. Housing starts in the Midwest also increased significantly over 1989 levels

while housing starts in the West remained at about the same level as a decade earlier. 

Table 4-7. Changes in Housing Starts by Region (1989 and 1999) 

Region 1989 Housing Starts

 (in thousands)

1999 Housing Starts 

(in thousands)

Percent Change from

1989 to 1999

Northeast 178.5 155.7 -12.77

Midwest 265.8 347.3 30.66

South 536.2 746.0 39.13

West 395.7 391.9 -0.96

Total 1,376.1 1,640.9 19.24

Source: BOC, 1999a, 2001
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June 2002 4-13

1988 1990 1992 1994 1996 1998 2000

Year

0

100

200

300

400

500

600

700

800

Annual Housing Starts (thousands)

Northeast Midwest South West

Figure 4-3. Annual Housing Starts by Region

4.2.3 NONRESIDENTIAL BUILDING CONSTRUCTION GROUP

The NAICS Nonresidential Building Construction group comprises establishments classified

either as Manufacturing and Industrial Building Construction or Commercial and Institutional

Building Construction. The following buildings are considered nonresidential by the U.S.

Census Bureau and fall under either the manufacturing or the commercial classification:

manufacturing and light industrial buildings; manufacturing and light industrial warehouses;

hotels and motels; office buildings; all other commercial buildings not elsewhere classified, such

as stores, restaurants, and automobile service stations; commercial warehouses; religious

buildings; educational buildings; health care and institutional buildings; public safety buildings;

nonresidential farm buildings; amusement, social, and recreational buildings; and all other

nonresidential buildings. Because of the transition from the SIC system used in the 1992

Economic Census to the NAICS for the 1997 census, a valid comparison of data between the two

censuses is not feasible, and therefore no historical data are shown.
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June 2002 4-14

Manufacturing and Industrial Building Construction. This industry type comprises

establishments primarily responsible for the entire construction of manufacturing and industrial

establishments, such as plants, mills, and factories. Establishments identified as management

firms for manufacturing and industrial building construction are also part of this industry. They

include manufacturing and industrial building general contractors, design builders, engineerconstructors, joint-venture contractors, and turnkey contractors (BOC, 1999e). 

In 1997, there were 7,280 manufacturing and industrial building construction establishments with

payroll (BOC, 1999e). These establishments employed 143,066 people for a total payroll of

more than $5.1 billion. The total value of manufacturing and industrial building construction

work in 1997 was more than $33.5 billion (BOC, 1999e). The value of construction work in

1997 by construction type is shown in Table 4-8 and includes new construction, additions,

alterations or reconstruction, maintenance and repair, and any construction work done by the

reporting establishments for themselves.

Table 4-9 shows the value U.S. of construction work for establishments with payroll by work

location. States are grouped into four geographic regions: Northeast, Midwest, South, and West. 

The South and the Midwest each accounted for approximately one-third of total 1997

construction value (southern region, approximately 32.4 percent; Midwest, nearly 30.1 percent). 

The West and Northeast made up the remaining third (West, 23.4 percent; Northeast, 11.1

percent). Of the 50 states, California had the highest value of construction work at $3.4 billion,

10.1 percent of the total for the entire United States. Michigan had the second-highest amount at

$2.9 billion (8.7 percent), followed by Texas at $1.9 billion (5.8 percent), and Ohio at $1.8

billion (5.3 percent). The remaining states and Washington, D.C., each had less than 5 percent of

the total value of manufacturing and industrial building construction work in the United States in

1997.
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June 2002 4-15

Table 4-8. Value of Construction Work for Manufacturing and Industrial Building

Construction Establishments With Payroll by Type of Construction, 1997

Type of Construction

Value of Construction Work (thousands of dollars)

Total New

Construction

Additions,

Alterations, or

Reconstruction

Maintenance

and Repair

Manufacturing and Light

Industrial Buildings $17,590,062 $10,914,455 $4,280,143 $2,395,463

Manufacturing and Light

Industrial Warehouses 7,058,148 5,421,819 1,358,864 277,466

Hotels and Motels 432,789 373,322 49,580 9,887

Office Buildings 2,478,594 1,570,275 810,808 97,511

All Other Commercial Buildings,

Not Elsewhere Classified 1,141,600 799,522 298,166 43,912

Commercial Warehouses 1,040,691 883,412 131,005 26,275

Educational Buildings 823,028 541,081 255,540 26,407

Health Care and Institutional

Buildings 862,907 464,788 355,116 43,003

All Other Nonresidential

Buildings 1,580,244 1,073,758 436,029 70,457

Building Construction, Total 33,008,063 22,042,431 7,975,252 2,990,381

Nonbuilding Construction, Total1 503,956 316,697 123,832 63,427

Construction Work, Not Specified

by Kind 2,324

Not

Applicable

Not

Applicable

Not

Applicable

Manufacturing and Industrial

Building Construction, Total2 $33,514,342 $22,359,127 $8,099,084 $3,053,807

1. This information is shown for the breakdown of total industrial building construction values. 

2. Detail may not add to total because of rounding.

Source: BOC, 1999e.
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June 2002 4-16

Table 4-9. Value of Manufacturing and Industrial Building

Construction Work for Establishments with Payroll

by Location of Construction Work, 1997 

(thousands of dollars)

Northeast Midwest South West

CT $260,593 IL $1,208,663 AL $1,080,420 AK $62,907

ME 170,314 IN 1,207,426 AR 182,142 AZ 561,785

MA 403,700 IA 381,922 DE 169,305 CA 3,440,637

NH 68,159 KS 281,419 DC 3,685 CO 330,551

NJ 755,854 MI 2,908,857 FL 920,179 HI S

NY 920,425 MN 593,542 GA 1,090,761 ID 776,661

PA 1,114,271 MO 745,632 KY 861,206 MT 26,176

RI D NE 221,626 LA 521,420 NV 86,998

VT 14,8121 ND 89,251 MD 253,778 NM 377,538

OH 1,772,426 MS 284,626 OR 895,078

SD D NC 921,364 UT 314,621

WI 669,575 OK 190,593 WA 915,678

SC 689,581 WY 52,326

TN 946,818

TX 1,934,909

VA 677,103

WV 144,481

Total: $3,708,1282 Total: $10,080,3392 Total: $10,872,3712 Total: $7,840,9562

Total Value of Construction for United States: 33,514,3422

D: Withheld to avoid disclosing data of individual companies; data are included in

United States total.

S: Withheld because estimates did not meet publication standards.

1. Sampling error exceeds 40 percent.

2. Totals for regions do not include states with “S” and “D” criteria.

Source: BOC, 1999e.
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June 2002 4-17

Commercial and Institutional Building Construction. This industry type comprises

establishments primarily responsible for the entire construction of commercial and institutional

buildings, such as stores, schools, hospitals, office buildings, and public warehouses (BOC, 

1999d). Establishments identified as management firms for commercial and institutional

building construction are also part of this industry type, which includes commercial and

institutional building general contractors, design builders, engineer-constructors, joint-venture

contractors, and turnkey contractors (BOC, 1999d). 

In 1997, there were 37,430 commercial and institutional building construction establishments in

the United States employing a total of 528,173 people, with a payroll of $19.2 billion (BOC, 

1999d). The value of construction work in 1997 by construction type is shown in Table 4-10. 

Value includes new construction, additions, alterations or reconstruction, maintenance and repair,

and any construction work done by the reporting establishments for themselves (BOC, 1999d). 

Table 4-11 shows the value of commercial and institutional building construction work by

location. The data are reported by state, by region (Northeast, Midwest, South, and West), and

for the entire United States. The South had the highest dollar value of construction activity,

accounting for $47.9 billion (27.7 percent) of commercial and institutional building construction

in the entire U.S. The West accounted for 20.6 percent of the total, followed by the Midwest at

16.8 percent, and then the Northeast at 9.7 percent. Of the 50 states, California had the highest

value of commercial and institutional construction work at $18 billion, or 10.4 percent of the

total for the entire United States. Texas had the second highest value of construction at

approximately $13 billion (7.5 percent), followed by Illinois at $7.9 billion (4.5 percent), and

then Georgia at $7.1 billion (4.1 percent). The remaining states and Washington, D.C. each

accounted for less than 4 percent of the total value of commercial and institutional building

construction work in the United States in 1997.
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June 2002 4-18

Table 4-10. Value of Construction Work for Commercial and Institutional

Building Construction Establishments With Payroll

by Type of Construction, 1997

Type of Construction

Value of Construction Work (thousands of dollars)

Total New

Construction

Additions,

Alterations, or

Reconstruction

Maintenance

and Repair

Single-Family Houses, Detached

and Attached $2,690,846 $1,473,065 $1,000,110 $217,672

Apartment Buildings,

Apartment.-Type Condominiums

and Cooperatives 4,081,493 2,905,159 1,016,097 160,237

Manufacturing and Light

Industrial Buildings 8,083,739 5,201,932 2,425,390 456,417

Manufacturing and Light

Industrial Warehouses 3,325,768 2,428,651 776,335 120,783

Hotels and Motels 8,313,559 6,433,138 1,679,856 200,564

Office Buildings 36,147,979 21,235,715 13,524,406 1,387,858

All Other Commercial Buildings,

Not Elsewhere Classified 32,715,012 21,866,915 9,631,103 1,216,994

Commercial Warehouses 6,929,460 5,465,600 1,215,709 248,151

Religious Buildings 4,324,007 2,870,724 1,342,559 110,724

Educational Buildings 23,974,844 15,587,110 7,893,507 494,227

Health Care & Institutional

Buildings 17,446,710 11,187,636 5,917,408 361,666

Public Safety Buildings 5,345,602 4,183,179 1,064,693 97,730

Farm Buildings, Nonresidential 1,904,128 1,508,380 272,836 122,912

Amusement, Social, and

Recreational Buildings 6,529,907 5,141,460 1,275,033 113,414

Other Building Construction 3,429,673 1,984,749 895,522 549,401

Building Construction, Total 166,818,246 110,618,170 50,325,006 5,875,070
Development Document for Construction and Development Proposed Effluent Guidelines

Type of Construction

Value of Construction Work (thousands of dollars)

Total New

Construction

Additions,

Alterations, or

Reconstruction

Maintenance

and Repair

June 2002 4-19

Nonbuilding Construction1 4,091,548 2,697,377 1,205,513 188,658

Construction Work, Not

Specified by Kind 2,295,888

Not

Applicable Not Applicable

Not

Applicable

Commercial and Institutional

Building Construction, Total2 $173,205,680 $113,315,547 $51,530,519 $6,063,728

1. This information is shown for the breakdown of total industrial building construction values. 

2. Detail may not add to total because of rounding.

Source: BOC, 1999d.
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June 2002 4-20

Table 4-11. Value of Commercial and Institutional Building

Construction Work for Establishments With Payroll

by Location of Construction Work, 1997 

(thousands of dollars)

Northeast Midwest South West

CT D IL 7,860,551 AL D AK 509,429

ME 385,818 IN 3,132,116 AR D AZ 3,287,644

MA 4,518,815 IA 1,610,654 DE 891,394 CA 18,093,906

NH 697,186 KS 1,609,747 DC 1,724,839 CO 3,728,688

NJ 4,973,021 MI 4,791,024 FL D HI D

NY D MN 3,361,074 GA 7,134,326 ID D

PA 5,966,516 MO D KY 1,961,212 MT 342,606

RI D NE 895,824 LA 1,855,800 NV D

VT 303,481 ND 297,619 MD 3,693,531 NM 913,252

OH 5,620,984 MS D OR 2,599,182

SD D NC 5,949,386 UT 1,796,639

WI D OK D WA 4,155,050

SC 2,417,316 WY 211,989

TN 3,751,331

TX 12,953,464

VA 5,076,575

WV 529,092

Total: $16,844,8371 Total: $29,179,5931 Total: $47,938,2661 Total: $35,638,3851

Total Value of Construction for United States: $173,205,6802

D: Withheld to avoid disclosing data of individual companies; data are included in

United States total.

1. Totals for regions do not include states with “D” criteria.

2. Detail may not add to total because of rounding, and because of “D” criteria.

Source: BOC, 1999d.
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June 2002 4-21

4.2.4 HEAVY CONSTRUCTION SUBSECTOR

Industry Overview. The heavy construction industry encompasses broad types of activities with 

highway and street construction; bridge and tunnel construction; and water, sewer, and pipeline

construction as the three main types of heavy construction. The U.S. Census Bureau administers

a separate economic census for each of these three types of construction activities. 

In general, most of the heavy construction industry indicators (e.g., value of completed work;

employment) have increased over the past two decades, although the health of the industry, like

that of the housing subsector, is closely tied to the overall state of the U.S. economy. This

subsector has experienced both upturns and downturns over the past 20-year period. 

The period encompassing the two most recent census years, 1992 and 1997, saw modest growth

in the heavy construction subsector. By 1997, the value of construction completed by the three

main types of heavy construction reached about $80 billion. As shown in Table 4-12, the

highway construction category of the heavy construction subsector accounted for about 60

percent of the total value of heavy construction. Highway construction employed the majority of

workers in the heavy construction subsector, accounting for about 278,000 of a total of 488,000

employees for all three categories of heavy contruction (BOC, 1999g). Of the three heavy

construction categories, only the water, sewer, and pipeline category has experienced a decline in

number of establishments and number of employees.

Regional Distribution of Heavy Construction Activities. The U.S. Bureau of Census reports data

for the heavy construction industries at the state and regional levels. As in the case of the

housing subsector, the Census Bureau divides the United States into four major regions,

Northeast, Midwest, South, and West, each contributing to the total value of construction work. 

As shown in Figure 4-4, the South and Midwest accounted for the majority of the establishments

and value of heavy construction work in 1997. In particular, these two regions accounted for 55

percent of the construction firms and 61 percent of the value of construction. 

Of the three major types of heavy construction activities, highway and street construction

accounted for almost 60 percent of the total value of heavy construction activities in 1997. The

distribution of highway construction establishments and the value of completed work among the

different regions of the country are similar to those of the other heavy construction categories

For example, the South contributed more than $16 billion, or 34 percent, to the total value of

highway construction work in the United States. It should be reiterated, however, that the census

provides only a snapshot and that construction activities such as highway construction are

dependent on government funding and can change significantly in magnitude and location over

time. 
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June 2002 4-22

Table 4-12. Overview of Heavy Construction

Industry, 1992 and 1997

Year Highway Bridges Water, Sewer,

and Pipeline

Value of Construction (thousands of dollars)

1992 35,331,607 7,198,275 20,205,048

1997 48,472,284 9,539,041 22,204,058

Number of Establishments

1992 10,090 1,041 10,233

1997 11,270 1,177 8,042

Number of Employees 1

1992 257,356 43,701 194,252

1997 277,979 47,764 162,566

1. Number of employees is the sum of all employees during

the pay periods that include the 12th of March, May, August,

and November, divided by four.

Source: BOC, 1992a, 1992b, 1992c, 1999f, 1999g, 1999h.
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June 2002 4-23

0

10

20

30

40

50

60

Northeast Midwest South West Total

Region

Value of Work (billions)

Highway Bridges Water, Sewer, and Pipeline

Figure 4-4. Value of Heavy Construction Work by Region, 1997

4.3 INDUSTRY PRACTICES AND TRENDS

4.3.1 OVERVIEW OF CONSTRUCTION LAND-DISTURBING ACTIVITIES

Constructing a building or facility involves a variety of activities, including the use of equipment

that alters the site’s environmental conditions. These changes include vegetation and top soil

removal, regrading, and drainage pattern alteration. The following provides a brief description of

typical land-disturbing activities at construction sites and the types of equipment employed. 

Construction Site Preparation. Construction activities generally begin with the planning and

engineering of the site and site preparation. During this stage, mobile offices, which are usually

housed in trailers, are established on the construction site. The construction company uses these

temporary structures to handle vital activities such as preparing and submitting applicable

permits, hiring employees and subcontractors, and ensuring that proper environmental

requirements are met. The entire construction yard is delineated with erosion and sediment

controls installed and security measures established. The latter includes installing fences and

signs to warn against trespassing and to mark dangerous areas. After the site is secured,

equipment is brought to the site (and is stored there throughout the construction period).
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June 2002 4-24

Clearing, Excavating, and Grading. Construction on any size parcel of land almost always calls

for a remodeling of the earth (Lynch and Hack,1984). Therefore, actual site construction begins

with site clearing and grading. Organic material cannot support the weight of buildings and

should be removed from the top layer of ground. (Some developers stockpile the organic material

for use during the landscaping phase of construction rather than paying for it to be hauled from

the site.) Construction contractors are to ensure that earthwork activities meet local, State, and

Federal regulations for soil and erosion control, runoff, and other environmental controls. The

size of the site, extent of water present, soil types, topography, and weather determine the kinds

of equipment used in site clearing and grading (Peurifoy and Oberlender, 1989). Material that

will not be used on the site should be hauled away by tractor-pulled wagons, dump trucks, or

articulated trucks (Peurifoy and Oberlender, 1989).

Equipment used for lifting excavated and cleared materials include aerial-work platforms,

forwarders, cranes, rough-terrain forklifts, and truck-mounted cranes. In addition, track loaders

are used for digging and dumping earth (Caterpillar, 2000; Construction Equipment On-Line,

1996-1998; Lynch and Hack, 1984; and Peurifoy and Oberlender, 1989).

Excavation and grading are performed by several different types of machines. These tasks can

also be done by hand, but this is generally more expensive (Lynch and Hack, 1984). When

grading a site, builders typically ensure that new grades are as close to the original as possible, to

avoid erosion and storm water runoff (Lynch and Hack, 1984). Proper grading also ensures a flat

surface for development and drains water away from constructed buildings. 

Excavation and grading equipment includes backhoes, bulldozers (including the versatile tracked

bulldozer), loaders, directional drilling rigs, hydraulic excavators, motor graders, scrapers,

skid-steer loaders, soil stabilizers, tool carriers, trenchers, wheel loaders, and pipeliners. 

Equipment selection depends on functions to be performed and specific site conditions

(Caterpillar, 2000; Construction Equipment On-Line, 1996-1998; Lynch and Hack, 1984; and

Peurifoy and Oberlender, 1989). Therefore, multiple types of equipment are used throughout the

clearing and grading process. 

Self-transporting trenching machines, wheel-type trenching machines, and ladder-type trenching

machines are also used during site excavation. Self-transporting trenching machines are used to

create shallow trenches, such as for underground wire and cables. This type of machine has a

bulldozer blade attached to the front, is highly maneuverable, and can be used to dig narrow,

shallow trenches. Wheel-type trenching machines also dig narrow trenches, most often for water

mains and gas and oil pipelines. Ladder-type trenching machines are used to dig deep trenches,

such as for sewer pipes. These machines might have a boom mounted at the rear. Along the

boom are cutter teeth and buckets that are attached to chains. As the machine moves, it digs dirt

and moves it to the sides of the newly formed trench (Peurifoy and Oberlender, 1989).
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June 2002 4-25

Power shovels can also be used for excavating soils. They are used on all classes of earth that

have not been loosened. For solid rock, prior loosening is often necessary. As materials are

excavated, they are immediately loaded onto trucks or tractor-pulled wagons and hauled from the

site (Peurifoy and Oberlender, 1989). Hydraulic excavators, with either a front or a back shovel,

are also used to dig into the earth and to load a hauling vehicle. There are several categories of

hydraulic excavators, including backhoes, back shovels, hoes, and pull shovels. Hydraulic

excavators are one of the most widely used types of excavating equipment because of their ease

of use and their ability to remove the earth that caves as it is moved. They are effective

excavating machines, and they are easy to use in terms of loading some sort of hauling vehicle 

(Peurifoy and Oberlender, 1989).

Draglines, used to dig ditches or build levees, can transport soil within casting limits, thus

eliminating the need for hauling equipment (Peurifoy and Oberlender, 1989). Draglines have a

bucket that hangs from a cable. The bucket is brought through the dirt and toward the operator

(Lynch and Hack, 1984). Draglines can be used on both wet and dry ground and can dig earth

out of pits that contain water (Peurifoy and Oberlender, 1989). They are most useful for making

large cuts and channels below the level of the machine as well as for making valleys, mounds,

slopes, and banks (Lynch and Hack, 1984). Draglines have a lower output than power shovels,

and do not excavate rock as well as power shovels (Peurifoy and Oberlender, 1989).

Draglines can be converted to clamshells by replacing the dragline bucket with a clamshell

bucket. A clamshell is typically used for handling sand, gravel, crushed stone, sandy loam, and

other loose materials; it is not efficient in handling compacted earth, clay, or other dense

materials. A clamshell is lowered into a material, and the bucket closes on the material. It is

then raised over a hauling vehicle and the materials deposited (Peurifoy and Oberlender, 1989).

Scrapers, either self-powered or drawn by tractors, dig and compact materials by taking up earth

from its underside with toothed scoops and loading it into hauling vehicles. Scrapers are useful

in removing earth and weak or broken rock, and for excavating hills and rock faces. Some

scrapers are designed for long hauls; others with good traction are used on steep slopes (Lynch

and Hack, 1984).

A crawler tractor, which pulls a rubber-tired self-loading scraper, is often used for short-haul

distances. The crawler tractor uses a drawbar pull to load the scraper. It has good traction and

can operate on muddy roads. It is, however, a slower vehicle and thus is more appropriate for

shorter hauls.

Wheel-type tractor-pulled scrapers, which come in two- and four- wheel tractors, are used for

longer hauling distances. Unlike the crawler tractor-pulled scrapers, the wheel-type tractorpulled scrapers do not maintain good traction. Under such conditions, a helper tractor, such as a

bulldozer, might be used (Peurifoy and Oberlender, 1989).
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June 2002 4-26

All these machines shape and compact the earth, a crucial site preparation step. In addition,

earthwork activities might suggest that fill be brought in. In such cases, the fill should be spread

in uniform, thick layers and compacted to a specified density with an optimum moisture content. 

Graders and bulldozers are the most common earth-spreading machines. Machines that compact

include tractor-pulled sheep's foot rollers, smooth-wheel rollers, pneumatic rollers, and vibrating

rollers, among other equipment (Peurifoy and Oberlender, 1989). Rollers and scarifiers are used

either to compact or to break up the ground (Lynch and Hack, 1984).

In order to remove rock, it should first be loosened and broken up, usually through drilling or

blasting. Drilling equipment includes jackhammers, wagon drills, drifters, churn rills, and rotary

drills; each is designed to work on a specific size and type of rock. Dynamite and other

explosives are used to loosen rock (Peurifoy and Oberlender, 1989).

Once materials have been excavated and removed and ground cleared and graded, the site is

ready for construction.

4.3.2 CONSTRUCTION SITE SIZE CATEGORIES AND ESTIMATES OF

AMOUNT OF DISTURBED LAND

The proposed effluent guidelines would apply to construction sites of all types (i.e., residential,

commercial, and industrial) of more than one acre (5 acres, in the case of the guideline’s Option

2). Because the costs of best management practices (BMPs) for erosion and sediment control are

largely driven by site size, EPA estimated the distribution of construction sites by size category,

land use type, and geographic region in order to estimate the total cost of the proposed rule. (In

addition, estimating distribution of sites by type allows EPA to estimate the cost to each

construction sector.) 

The method used to estimate the number of construction sites by size category, and therefore the

total area disturbed, is based on a number of data sources, including U.S. Census data and data

collected during the Phase II Storm Water rulemaking.

4.3.2.1 National Estimates of Disturbed Acreage

EPA used the U.S. Department of Agriculture’s (USDA’s) 1997 National Resources Inventory

(NRI) to estimate the level of new U.S. development each year. (NRI is designed to track

changes in land cover and land use over time.) The inventory, conducted every five years, covers

all non-federal lands in the U.S. (75 percent of the U.S. total). The program captures land use

data from some 800,000 statistically selected locations. From 1992 to 1997, an average of 2.2

million acres per year were converted from non-developed to developed status. Table 4-13

shows the allocation of this converted land area by type of land or land cover.
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June 2002 4-27

Table 4-13. Acres Converted from Undeveloped to Developed Statea,

1992-1997 

Type of Land

Acres Converted to

Development 1992-1997

(thousands) 

Annual Average

Percent Contribution by 

Type of Land

Cropland 574.8 26.6%

Conservation Reserve

Program land

1.5 0.1%

Pastureland 391.2 17.4%

Rangeland 245.9 11.0%

Forest land 939.0 41.9%

Other rural area 89.1 4.0%

Water areas and federal land 1.8 0.1%

Total 2,243.4 100.0%

a. NRI defines developed land as a combination of the following land cover/use categories

large urban and built-up areas, small built-up areas, and rural transportation land. 

These are defined as follows:

Large urban and built-up areas. A land cover/use category composed of developed tracts

of at least 10 acres and meeting the definition of urban and built-up areas.

Small built-up areas. A land cover/use category consisting of developed land units of 0.25

to 10 acres, which meet the definition of urban and built-up areas.

Rural transportation land. A land cover/use category which consists of all highways,

roads, railroads and associated right-of-ways outside urban and built-up areas; also

includes private roads to farmsteads or ranch headquarters, logging roads, and other

private roads (field lanes are not included).

Urban and built up areas are in turn defined as:

Urban and built-up areas. A land cover/use category consisting of residential, industrial,

commercial, and institutional land; construction sites; public administrative sites; railroad

yards; cemeteries; airports; golf courses; sanitary landfills; sewage treatment plants; water

control structures and spillways; other land used for such purposes; small parks (less than

10 acres) within urban and built-up areas; and highways, railroads , and other

transportation facilities if they are surrounded by urban areas. Also included are tracts of

less than 10 acres that do not meet the above definition but are completely surrounded by

Urban and built-up land. Two size categories are recognized in the NRI: areas of 0.25 acre

to 10 acres, and areas of at least 10 acres.

Source: USDA, 2000.
Development Document for Construction and Development Proposed Effluent Guidelines

June 2002 4-28

4.3.2.2 Distribution of Acreage by Project Type

To allocate the NRI acreage among the various segments of the industry, EPA has estimated the

distribution of acres developed by type of project in the following way. First, EPA multiplied

the number of building permits issued annually by estimates of the average site size for each

project type. Thus for single-family residential construction, EPA multiplied the number of new

single-family home building permits by the average lot size for new single-family construction. 

Estimates for other types of construction were based on extrapolations from the U.S. Census

permit data and EPA estimates of average project size. Second, EPA adjusted the estimates of

acres converted to reconcile any differences between the total number of acres accounted for

using this approach and the total acres developed as estimated in the NRI.

Single-family Residential

Census data indicate that in recent years the number of new single-family housing units

authorized has averaged just over 1.0 million units per year (see Table 4-14). The average lot

size for new single-family housing units is 13,553 square feet, or 0.31 acres (1 acre = 43,560

square feet). Using the average lot size (see Table 4-15), however, will underestimate the total

acreage converted for single-family residential projects because it does not include common

areas of developments not counted as part of an owner’s lot. These areas include streets,

sidewalks, parking areas, storm water management structures, and open spaces.

Table 4-14. New Single-Family and Multifamily Housing

Units Authorized, 1995-1997

Year All Housing Units Single-Family 

Housing Units

Multifamily 

Housing Units

1995 1,332,549 997,268 335,281

1996 1,425,616 1,069,472 356,144

1997 1,441,136 1,062,396 378,740

1995-1997 avg 1,399,767 1,043,045 356,722

Source: BOC, 2000b.
Development Document for Construction and Development Proposed Effluent Guidelines

6 The communities were: Austin, TX; Baltimore County, MD; Cary, NC; Ft. Collins, CO; Lacey, WA;

Loudoun County, VA; New Britain, CT; Olympia, WA; Prince George’s County, MD; Raleigh, NC; South Bend,

IN; Tallahassee, FL; Tuscon, AZ; and Waukesha, WI.

June 2002 4-29

Table 4-15. Average and Median Lot Size

for New Single-Family 

Housing Units Sold, 1995-1997

Year Average Lot Size 

(Square Feet)

Median Lot Size 

(Square Feet)

1995 13,665 9,375

1996 13,705 9,100

1997 13,290 9,000

1995-1997 avg 13,553 9,158

Source: BOC, 1995, 1996, 1997.

To account for these differences, EPA examined data obtained from a survey of municipalities

conducted in support of the Phase II Storm Water rule (EPA 1999). This survey identified 14

communities that consistently collected project type and size data as part of their construction

permitting programs.6

 EPA’s review of permitting data from these communities covered 852

single-family developments encompassing 18,134 housing units. The combined area of these

developments was 11,460 acres. This means that each housing unit accounted for 0.63 acres

(11,460 acres ÷ 18,134 units = 0.63 acres per unit). This estimate, essentially double the average

lot size, appears to more than account for the common areas and undeveloped areas in a typical

single-family residential development. For this reason, EPA averaged the Census estimate of the

national average lot size (0.31 acres) and the Phase II estimate of 0.63 acres per unit to arrive at

an estimate of 0.47 acres per unit. This number was multiplied by the average number of singlefamily housing units authorized by building permit, 1.04 million, to arrive at an estimate of

490,231 acres (see Table 4-18).

Multifamily Residential

For residential construction other than single-family housing, EPA divided the average number

of units authorized during 1995-1997 (356,722, from Table 4-14) by the average number of units

per new multifamily building. The average number of units per building was obtained by

examining the distribution of units by unit size class in Census data (BOC 2000b). EPA

estimated the number of buildings in each size class by dividing the number of units in each class

by the average number of units. The total number of units was then divided into the estimated

number of buildings to arrive at an average number of approximately 10 units per building across
Development Document for Construction and Development Proposed Effluent Guidelines

June 2002 4-30

all building size classes. Dividing 356,722 units authorized (Table 4-14) by 10 units per building

project yields 35,672 individual development projects.

EPA next examined data on the average site size for multifamily residential developments. The

Center for Watershed Protection reports survey results showing that an average building footprint

occupies 15.6 percent of the total site (CWP 2001). EPA assumed that the average-sized

multifamily building (10.8 units) would have two floors and that each unit would occupy the

national average of 1,095 square feet (NAHB 2002). The total square footage accounted for by

living space is thus 11,826 square feet. Multiplying by a factor of 1.2 to account for common

areas and other non-living space (utility rooms, hallways, stairways), and dividing by 2 to reflect

the assumption of a 2-story structure, EPA obtained a typical building footprint of 7,096 square

feet (11,826 x 1.2 ÷ 2 = 7,096). Combining this with the CWP estimate of the building footprint

share of total site size (15.6 percent), the average site size was estimated to be 45,487 square feet

(7,096 ÷ 0.156 = 45,487), or just over 1 acre (1.04 acres). 

EPA compared the average site size obtained using this approach with data from the 14

community survey referenced above under the Phase II Storm Water rule. That study’s review of

permitting data identified 286 multifamily developments covering a total of 3,476 acres. The

average site size, 12.1 acres, is considerably higher than that calculated above. EPA has no

indication that the permits reviewed in these communities are for projects of a larger-thanaverage size. Therefore, for purposes of this analysis, EPA has taken the midpoint of the

estimates, 6.5 acres, as the average size of multifamily projects. This number was multiplied by

the average number of multifamily housing developments authorized by building permit, 35,672,

to arrive at an estimate of 231,868 acres (see Table 4-18).

Nonresidential Construction

EPA lacked current data on the number of nonresidential construction and development projects

authorized annually because the Census Bureau ceased to collect data on the number of permits

issued for such projects in 1995. EPA used regression analysis to forecast the number of

nonresidential building permits issued in 1997, based on the historical relationship between

residential and nonresidential construction activity. Using this approach, EPA estimates that a

total of 426,024 nonresidential permits were issued in 1997. These represent a variety of project

types, including commercial and industrial, institutional, recreational, as well as nonresidential,

nonbuilding projects such as parks and road or highway projects. 

EPA first combined a number of project types into a larger “commercial” category, which

included hotels and motels and retail and office projects, as well as religious, public works, and
Development Document for Construction and Development Proposed Effluent Guidelines

7 The commercial category included: hotels/motels, amusement, religious, parking garages, service

stations, hospitals, offices, public works, educational, stores, and other nonresidential buildings.

June 2002 4-31

educational projects.7 EPA’s reasoning for including the latter categories under the commercial

category is based on engineering judgment that erosion and sediment control practices would be

similar across each project type. The total estimated number of commercial permits in 1997 was

254,566 (59.7 percent of the nonresidential total). (EPA calculated a estimate for the industrial

category, which totaled 12,140 permits (2.8 percent), separately.) The residual 159,318 permits

(37.4 percent), are nonbuilding, nonresidential projects that include parks, bridges, roads, and

highways. EPA accounts for these projects in the steps described below. 

For the industrial and commercial categories, EPA reviewed the project size data collected from

the 14-community Phase II rule survey referenced earlier (EPA, 1999). This study identified 817

commercial sites occupying 5,514 acres and 115 industrial sites occupying 689 acres. The

average site sizes are 6.7 and 6.0 acres, respectively. 

EPA also reviewed estimates from CWP (2001) on the average percent of commercial and

industrial sites taken up by the building footprint. These percentages, 19.1 and 19.6 respectively,

were multiplied across the model project site sizes of 1, 3, 7.5, 25, 70, and 200 acres to estimate

building size on each site, assuming single-story buildings in each case. These estimates are

shown in Table 4-16.

Table 4-16. Average Building Area

(square feet)

Project Size

(Acres) Commercial Industrial

1 8,320 8,555

3 24,960 25,666

7.5 62,400 64,164

25 207,999 213,880

70 582,397 598,863

200 1,663,992 1,711,037

Estimates were obtained by multiplying the site size in square

feet by the percentage of the site estimated to be occupied by

the building "footprint," based on data from CWP (2001).

As seen in the table, the average building size corresponding to the 6- to7- acre sites estimated

from the 14-community study are in the 60,000 square feet range. EPA next examined R.S.
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June 2002 4-32

Means’ Building Construction Cost Data (2000), which provides cost data for “typical”

commercial and industrial buildings. As part of the cost data, R.S. Means identifies the typical

range of building sizes based on a database of actual projects. Table 4-17 shows the typical size

and size range for a variety of building types that would fall into either the commercial or

industrial category. While some of the building types correspond with the estimated average of

60,000 square feet, these appear high for other categories, such as low-rise office and

supermarkets, warehouses, and elementary schools. EPA believes generally that there are more

small projects than large ones. As a result, EPA inferred that this approach would suggest an

average building size of 25,000 square feet, which implies an average site size of 3 acres, based

on Table 4-16.

To reconcile the estimates obtained from the two approaches, EPA has taken the midpoint of the

estimates. For commercial development, EPA assumes an average site size of 4.85 acres (the

average of 6.7 and 3.0 acres) and for industrial development EPA assumes an average site size of

4.5 acres (the average of 6.0 and 3.0 acres).

Table 4-17. Typical Building Sizes and Size Ranges by Type of

Building

Building Category/Type

Typical Size 

(Gross Square

Feet)

Typical Range

(Gross Square Feet)

Low High

Commercial - Supermarkets 20,000 12,000 30,000

Commercial - Department

Store 90,000 44,000 122,000

Commercial - Low-Rise Office 8,600 4,700 19,000

Commercial - Mid-Rise Office 52,000 31,300 83,100

Commercial - Elementarya 41,000 24,500 55,000

Industrial - Warehouse 25,000 8,000 72,000

a. For purposes of this analysis EPA combines a number of building types, including

educational, under the commercial category.

Source: R.S. Means, 2000.

The resulting average project sizes were then multiplied by the estimated number of commercial

and industrial permits to obtain an estimate of the total acreage developed (and thus land acreage

disturbed) for these project categories. Table 4-18 shows the results of this “bottom-up”

approach to estimating the number of acres of land developed. The overall estimate of the

amount of land developed is 2.01 million acres per year. Residential single-family development
Development Document for Construction and Development Proposed Effluent Guidelines

June 2002 4-33

accounts for 24.4 percent of the total, multifamily development for 11.5 percent of the total,

commercial for 61.4 percent, and industrial for 2.7 percent.

Table 4-18. National Estimates of Land Area Developed Per Year,

Based on Building Permit Data

Type of Construction

Permits

Average

Site Sizea

Acres Disturbed

Number Pct. of

Total Number Pct. of total

Residential Single-family 1,043,045 77.5% 0.47 490,231 24.4%

Multifamily 35,672 2.7% 6.5 231,868 11.5%

Nonresidential Commercialb 254,566 18.9% 4.9 1,234,645 61.4%

Industrial 12,140 0.9% 4.5 54,630 2.7%

Total 1,345,423 100.0% -- 2,011,374 100.0%

a. For single-family residential, this is the average of the average lot size for new construction in 1999

(BOC, 2000b) and the average obtained in EPA (1999). For all other categories, the site sizes are EPA

assumptions based on representative project profiles contained in R.S. Means (2000) and the 14-

community survey conducted in support of the Phase II NPDES storm water rule (EPA, 1999).

b. A number of project types were grouped together to form the “commercial” category, including:

hotels/motels, amusement, religious, parking garages, service stations, hospitals, offices, public works,

educational, stores, other nonresidential buildings. 

The estimate of 2.01 million acres (Table 4-18) of annual construction is close to the estimated

2.24 million acres of annual new urban land obtained from 1997 NRI. Areas not accounted for

in EPA’s estimates include those converted as a result of road, highway, bridge, park, monument,

and other non-building construction projects. EPA has not developed engineering costs

applicable to these types of projects, but assumes that the builders and developers of these areas

will face similar compliance costs per acre to the residential, commercial and industrial sectors,

and therefore, the acreage should be included in EPA’s analysis. For the purpose of developing

national compliance costs, therefore, EPA has allocated the entire annual new urban acreage

from the 1997 NRI into the four land use categories using the distribution shown in the final

column of Table 4-18. The third column in Table 4-19 summarizes the results of this allocation. 

EPA next adjusted the annual developed acreage to account for sites that would not be required

to obtain a permit due to the low rainfall erosivity waiver contained in the Phase II rule, as well

as to eliminate sites less than 1 acre. EPA estimated based on the Phase II economic analysis

that 33,517 acres would qualify for a low soil loss waiver, and analysis of the 14 community

survey data indicates that 33,828 acres would be in sites less than 1 acre. This yields 67,345

acres of annual new development that would not be within the scope of the proposal. EPA

allocated this acreage among the four land uses based on an analysis of the number of permits
Development Document for Construction and Development Proposed Effluent Guidelines

June 2002 4-34

less than five acres contained within each respective segment. The results of this allocation are

contained in the fourth column of Table 4-19, and the revised NRI acreage accounting for

waivers and sites less than 1 acre is presented in the last column Table 4-19. EPA further

estimated acreage that would be eliminated from coverage given the 5 acre cutoff contained in

Option 2. A discussion of this analysis is included in the Economic Analysis supporting

document. 

Table 4-19. National Estimates of Land Area Disturbed Based on

National Resources Inventory Totals

Type of Construction Total NRI

Acreagea

Acres Waived or

not Covered

Adjusted NRI

Acreageb

Residential Singlefamily546,783 12,905 533,878

Multifamily 258,616 6,434 252,182

Nonresidential Commercialc 1,377,070 44,594 1,332,476

Industrial 60,932 3,412 57,523

Total 2,243,400 67,345 2,176,058

a. This column distributes the total acreage estimated in NRI to be converted on an

annual basis (adjusted for waivers) according to the distribution by type of development

estimated through analysis of permits data contained in Table 4-18.

b. This column presents the total national acreage estimated after adjusting for rainfall

erosivity waivers and sites less than 1 acre.

c. A number of project types were grouped together to form the “commercial” category,

including: hotels/motels, amusement, religious, parking garages, service stations,

hospitals, offices, public works, educational, stores, other nonresidential buildings. 

4.3.2.3 Distribution of Developed Acreage by Project Size and Geography

For each of the four land use categories in Table 4-19, EPA developed a distribution to allocate

developed acre estimates among six different project size categories. The project size

distribution is based on a survey of construction permits issued in 14 communities conducted in

support of the Phase II storm water rule. Table 4-20 shows the distribution of the 14 community

survey data by project size for each land use category. The percentages shown in Table 4-20

were used to allocate the total estimated development within each of the four land use sectors in

Table 4-19 into six site size categories. The results of this analysis are presented in Table 4-21.
Development Document for Construction and Development Proposed Effluent Guidelines

June 2002 4-35

In addition, EPA developed procedures to spatially distribute land development regionally, using

19 ecoregions covering the contiguous states. A description of this methodology is presented in

the Environmental Assessment supporting document.
Development Document for Construction and Development Proposed Effluent Guidelines

June 2002 4-36

Table 4-20. Distribution of 14 Community Survey

Permits by Site Size

Site Size (Acres) No. of

Permits Acres by Size Pct. Acres by Size

Single-Family Residential

1 266 266 2.3%

3 228 684 6.0%

7.5 138 1,035 9.0%

25 175 4,375 38.2%

70 30 2,100 18.3%

200 15 3,000 26.2%

Total 852 11,460 100.0%

Multifamily Residential

1 43 43 1.2%

3 100 300 8.6%

7.5 61 458 13.2%

25 71 1,775 51.1%

70 10 700 20.1%

200 1 200 5.8%

Total 286 3,476 100.0%

Commercial

1 266 266 4.8%

3 356 1,068 19.4%

7.5 86 645 11.7%

25 91 2,275 41.3%

70 16 1,260 22.9%

200 0 0 0.0%

Total 815 5,514 100.0%
Development Document for Construction and Development Proposed Effluent Guidelines

Table 4-20. Distribution of 14 Community Survey

Permits by Site Size

Site Size (Acres) No. of

Permits Acres by Size Pct. Acres by Size

June 2002 4-37

Industrial

1 39 39 5.7%

3 55 165 23.9%

7.5 10 75 10.9%

25 8 200 29.0%

70 3 210 30.5%

200 0 0 0.0%

Total 115 689 100.0%

Total

1 614 614 2.9%

3 739 2,217 10.5%

7.5 295 2,213 10.5%

25 345 8,625 40.8%

70 59 4,270 20.2%

200 16 3,200 15.1%

Total 2,068 21,139 100.0%

Based on permitting data from the following municipalities or counties:

Austin, TX; Baltimore County, MD; Cary, NC; Ft. Collins, CO; Lacey,

WA; Loudoun County, VA; New Britain, CT; Olympia, WA; Prince

George’s County, MD; Raleigh, NC; South Bend, IN; Tallahassee, FL;

Tucson, AZ; and Waukesha, WI.

Source: USEPA, 1999
Development Document for Construction and Development Proposed Effluent Guidelines

June 2002 4-38

Table 4-21. Distribution of National Construction by Site

Size and Development Type

Site Size (Acres) No. of

Permits Acres by Size Pct. Acres by Size

Single-Family Residential

1 12,392 12,392 2.3%

3 10,622 31,865 6.0%

7.5 6,429 48,217 9.0%

25 8,153 203,815 38.2%

70 1,398 97,831 18.3%

200 699 139,759 26.2%

Total 39,691 533,878 100.0%

Multifamily Residential

1 3,120 3,120 1.2%

3 7,256 21,768 8.6%

7.5 4,426 33,196 13.2%

25 5,152 128,794 51.1%

70 726 50,792 20.1%

200 73 14,512 5.8%

Total 20,752 252,182 100.0%

Commercial

1 64,280 64,280 4.8%

3 86,029 258,086 19.4%

7.5 20,782 155,866 11.7%

25 21,990 549,761 41.3%

70 4,350 304,483 22.9%

200 0 0 0.0%

Total 197,431 1,332,476 100.0%
Development Document for Construction and Development Proposed Effluent Guidelines

Table 4-21. Distribution of National Construction by Site

Size and Development Type

Site Size (Acres) No. of

Permits Acres by Size Pct. Acres by Size

June 2002 4-39

Industrial

1 3,256 3,256 5.7%

3 4,592 13,775 23.9%

7.5 835 6,262 10.9%

25 668 16,698 29.0%

70 250 17,532 30.5%

200 0 0 0.0%

Total 9,601 57,523 100.0%

Totals

1 83,048 83,048 3.8%

3 108,498 325,494 15.0%

7.5 32,472 243,541 11.2%

25 35,963 899,067 41.3%

70 6,723 470,638 21.6%

200 771 154,271 7.1%

Grand Total 267,475 2,176,059 100.0%

Based on permitting data from the following municipalities or counties: Austin,

TX; Baltimore County, MD; Cary, NC; Ft. Collins, CO; Lacey, WA; Loudoun

County, VA; New Britain, CT; Olympia, WA; Prince George’s County, MD;

Raleigh, NC; South Bend, IN; Tallahassee, FL; Tuscon, AZ; and Waukesha, WI.

Source: USEPA, 1999.

4.4 REFERENCES

BOC. 1992a. 1992 Census of Construction Industries: Highway and Street Construction

Contractors, Except Elevated Highways. U.S. Bureau of the Census, Washington, DC.

http://www.census.gov/prod/1/constr/92ind/cci06f.pdf. Accessed May 21, 2002.
Development Document for Construction and Development Proposed Effluent Guidelines

June 2002 4-40

BOC. 1992b. 1992 Census of Construction Industries: Bridge, Tunnel and Elevated Highway

Construction Contractors. U.S. Bureau of the Census, Washington, DC.

http://www.census.gov/prod/1/constr/92ind/cci07f.pdf. Accessed May 21, 2002.

BOC. 1992c. 1992 Census of Construction Industries: Water, Sewer, Pipeline and

Communications and Powerline Construction. U.S. Bureau of the Census, Washington,

DC. http://www.census.gov/prod/1/constr/92ind/cci08f.pdf. Accessed May 21, 2002.

BOC. 1995. Characteristics of New Housing: 1995, Current Construction Reports. U.S. Bureau

of the Census, Washington, DC. http://www.census.gov/prod/1/constr/c25/c25_95a.pdf.

Accessed May 28, 2002. 

BOC. 1996. Characteristics of New Housing: 1996, Current Construction Reports. U.S. Bureau

of the Census, Washington, DC. http://www.census.gov/prod/1/constr/c25/c25-96a.pdf. 

Accessed May 28, 2002.

BOC. 1997. Characteristics of New Housing: 1997, Current Construction Reports. U.S. Bureau

of the Census, Washington, DC. http://www.census.gov/prod/3/98pubs/c25-97a.pdf. 

Accessed May 28, 2002.

BOC. 1999a. Housing Starts, Current Construction Reports. U.S. Bureau of the Census, 

Washington, DC. http://www.census.gov/prod/99pubs/c20-9901.pdf. Accessed October

1, 2000.

BOC. 1999b. Single-family Housing Construction, 1997 Economic Census, 

Construction Industry Series. U.S. Bureau of the Census, Washington, DC.

http://www.census.gov/prod/ec97/97c2332a.pdf. Accessed October 2, 2000.

BOC. 1999c. Multifamily Housing Construction, 1997 Economic Census, Construction Industry

Series. U.S. Bureau of the Census, Washington, DC.

http://www.census.gov/prod/ec97/97c2332b.pdf. Accessed October 15, 2000.

BOC. 1999d. Commercial and Institutional Building Construction, 1997 Economic Census,

Construction Industry Series. U.S. Bureau of the Census, Washington, DC.

http://www.census.gov/prod/ec97/97c2333b.pdf. Accessed October 25, 2000.

BOC. 1999e. Manufacturing and Industrial Building Construction, 1997 Economic Census,

Construction Industry Series. U.S. Bureau of the Census, Washington, DC.

http://www.census.gov/prod/ec97/97c2333a.pdf. Accessed October 25, 2000.
Development Document for Construction and Development Proposed Effluent Guidelines

June 2002 4-41

BOC. 1999f. Water, Sewer, Pipeline Construction, 1997 Economic Census, Construction

Industry Series. U.S. Bureau of the Census, Washington, DC.

http://www.census.gov/prod/ec97/97c2349a.pdf. Accessed October 25, 2000.

BOC. 1999g. Highway and Street Construction Contractors. U.S. Bureau of the Census,

Washington, DC. http://www.census.gov/prod/ec97/97c2341a.pdf. Accessed October 25,

2000.

BOC. 1999h. Bridge and Tunnel Construction. U.S. Bureau of the Census, Washington, DC. 

http://www.census.gov/prod/ec97/97c2341b.pdf. Accessed October 25, 2000.

BOC. 2000a. 1997 Economic Census-construction Sector Special Study: Housing Start

Statistics, a Profile of the Homebuilding Industry. Issued July 2000. U.S. Bureau of the

Census, Washington, DC.

BOC. 2000b. New Privately Owned Housing Units Authorized by Building Permits in Permitissuing Places, Annual Data. U.S. Bureau of the Census, Washington, DC.

BOC. 2001. New Privately Owned Housing Units Started: Annual Data, 2001. U.S. Bureau of

the Census, Washington, DC. http://www.census.gov/const/startsan.pdf. Accessed May

23, 2002. 

Caterpillar. 2000. Caterpillar, Inc. http://www.cat.com

Construction Equipment On-line. 2000. Reed Business Information, U.S. www.coneq.com

CWP. 2001. Impervious Cover and Land Use in the Chesapeake Bay Watershed. Ellicott City,

MD: Center for Watershed Protection, January. Additional data table, “Chesapeake bay

watershed impervious cover results by land use polygon,” received via a facsimile from

Tetra Tech, Inc., September 20, 2001.

Lynch, Kevin and Hack, Gary. 1984. Site Planning (3rd ed.). Cambridge, MA: MIT Press.

NAHB. 2002. Characteristics of New Multifamily Buildings 1987-1999. National Association

of Home Builders. http://www.nahb.com/multifamily/characteristics.htm. Accessed May

29, 2001. 

NAICS. 1997. North American Industry Classification System–U.S. U.S. Department of

Commerce, National Technical Information Service, Washington, DC.

Peurifoy, Robert L. and Oberlender, Garold D. (1989). Estimating Construction Costs (4th ed.).

New York: McGraw Hill Book Company. 
Development Document for Construction and Development Proposed Effluent Guidelines

June 2002 4-42

R.S. Means. 2000. Building Construction Cost Data 58th Annual Edition. R.S. Means Co.,

Kingston, Massachusetts.

R.S. Means. 2001. Heavy Construction Cost Data 15th Annual Edition. R.S. Means Co.,

Kingston, Massachusetts.

USDA. 2000. 1997 National Resources Inventory. U.S. Department of Agriculture, National

Resources Conservation Service, Washington, DC. www.nrcs.usda.gov/technical/NRI/. 

USEPA. 1999. Economic Analysis of the Final Phase II Storm Water Rule. U.S. Environmental

Protection Agency, Office of Wastewater Management. Washington, DC.

U.S. Housing Markets. 1998. Homebuilders Face a Steep Climb Chasing a 20-year-old-family

Mark. Meyers Real Estate Information, Inc.

http://www.housingusa.com/ushm/pr/ushm998.pr.html. Accessed October 25, 2000.

U.S. Housing Markets. 1999a. Busiest Markets, Single-family Building. Meyers Real Estate

Information, Inc.

http://www.housingusa.com/ushm/pmts/mulbuzz.html. Accessed October 25, 2000.

U.S. Housing Markets. 1999b. Busiest Markets, Multifamily Construction. Meyers Real Estate

Information, Inc.

http://www.housingusa.com/ushm/pmts/mulbuzz.html Accessed October 25, 2000.
Development Document for Construction and Development Proposed Effluent Guidelines

June 2002 5-1

SECTION 5: TECHNOLOGY ASSESSMENT

This technology assessment of available data sources is intended to determine the depth and

breadth of effectiveness data for various erosion and sediment controls, and to identify the

amount and quality of data available to describe the performance of all currently used and

innovative runoff control practices, the ability of each practice to effectively control impacts due

to runoff, and the design criteria or standards currently used to size each practice to ensure

effective control of runoff.

5.1 CONSTRUCTION EROSION AND SEDIMENT CONTROLS

5.1.1 INTRODUCTION

Part 1, reported in this sub-section, addresses the erosion and sediment control BMPs for the

construction phase of development. Prior to initiating this aspect of the work, EPA reviewed the

findings of information sources and literature assessments to identify the appropriate definition

of “performance” or the various definitions or “levels” of performance that are considered in

evaluating and defining the levels of performance for these BMPs. A scientific-based approach

to describe the performance of erosion and sediment control BMPs was devised similar to the

approach developed by Barfield and Clar (1985) in the evaluation of the Maryland Erosion and

Sediment Control Standards, as well as the one recently developed in the American Society of

Civil Engineers BMP Database (ASCE, 1999). The approach used in this assessment has been

designed to provide the information needed to address several important issues, including

whether to use a design-based approach, or an effluent-based concentration, or a loading

approach in reporting on the current status of the technology. This sub-section identifies the

following:

• The amount and quantity of data available to describe the performance of all currently used

and innovative runoff control practices.

• The ability of each practice to effectively control impacts due to runoff.

• The design criteria or standards currently used to size each practice to ensure effective

control of runoff. 

Before a detailed evaluation of the BMPs can be provided, some background information is

necessary. Sub-section 5.2 describes the procedure for assessing the technology. Sub-section

5.3 provides a historical background on the subject. Next, sub-section 5.4 presents a discussion

of goals, control strategies, criteria, and standards in general, and sub-section 5.5 provides a

detailed description and discussion of each BMP.
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In the discussion of BMPs in sub-section 5.5, the major focus will be on sediment. This does not

imply that there are no other impacts; however, construction BMPs have focused on erosion and

sediment control rather than on other impacts.

In the assessment of BMPs, considerable attention is focused on whether to use a design-based

approach, an effluent-based concentration, or a loading approach in reporting on the current

status of the technology. Attention is also given to the recent emphasis in the literature on the

use of an integrated approach to evaluate impacts to the receiving waters and downstream areas. 

5.1.2 PROCEDURE FOR TECHNOLOGY ASSESSMENT

5.1.2.1 IDENTIFICATION OF PERFORMANCE GOALS

In assessing the literature, particular consideration was given to definitions of performance of

BMPs and how they addressed the range of receiving water impacts identified. It is important to

point out that the overarching performance goal of all the BMPs is to minimize the impact of

construction site runoff on receiving waters and downstream areas. 

Control strategies that have been identified for construction BMPs can be divided into three

categories. 

Strategy 1. Control Based on Design Standards—Control at this level is based on standard

designs that may include such things as volume requirements for reservoirs, detention time, and

trapping efficiency that do not directly limit an allowable discharge to receiving waters or limit a

downstream impact.

Strategy 2. Control Based on Effluent Standards—Control at this level is based on limiting the

quantity of one or more substances such as peak discharge, runoff volume, TSS, and settleable

solids. This directly addresses effluent, but does not directly address downstream impacts.

Strategy 3. Control Based on an Integrated Approach—Control at this level uses an integrated

approach (Snodgrass et al., 1998), including biological, chemical, and physical criteria, to define

BMP performance. A combination of water quality, biohabitat, and geomorphic criteria is used

to evaluate whether a receiving stream is at the targeted goal of fishable and swimmable, or the

extent of departure from this goal. 

The majority of BMPs address Strategies 1 or 2. Although Strategy 3 is being discussed in the

literature, it has not been adopted in practice. There is an analog in the surface mining industry,

where a cumulative hydrologic impact analysis on a watershed basis is required by the U.S.

Surface Mining and Reclamation Act of 1977 (PL95-87). When moving from Strategy 2 to

Strategy 3, a number of other parameters are added to the performance criteria in Strategy 2,
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including (1) stream buffer retention and thermal impacts considerations, (2) volume control

considerations such as are presented in the Low Impact Development concept approach, which

are added to the peak discharge and ground water recharge criteria to achieve maintenance of

hydrologic function at a site-specific level, and (3) geomorphic criteria as described by Lane

(1955), Leopold et al. (1964), Rosgen (1996), and others.

An important point must be made about controlling sediment. From a practical standpoint, a

reasonably sized structure should not necessarily be expected to meet an effluent TSS standard

unless the TSS specified in the standard is set at a very high value or unless some form of

chemical treatment is used to enhance flocculation. The settling velocity for primary clay

particles is in the range of feet per month for all but the largest particles. Since these size

particles are frequently encountered in large percentages in sediment from construction sites, the

expected trapping efficiencies will not approach 100 percent, nor will the effluent TSS be in the

range of 100 mg/L or lower (Haan et al., 1994).

5.1.2.2 GOALS, ENVIRONMENTAL IMPACT AREAS, AND ASSESSMENT

SCALES

For the purposes of this report, impact areas are divided into three categories, local area,

receiving water, and downstream areas.

Local Area. This is the area between the construction site and the receiving stream. Typically,

these areas have ephemeral streams with low baseflows and highly variable flow rates. In these

areas, the flows fluctuate widely, with geomorphology and habitat being very susceptible to

changes in hydrologic regime (Klaine, 2000). In some developments, there would essentially be

no local area, and flows would exit directly into receiving waters.

Receiving Waters. This is the point at which flows enter a well-defined stream. Depending on

the local geology, flows may primarily be ephemeral, there may be a well-established baseflow,

or there may be something intermediate between the two extremes. The degree to which flows,

sediment, and chemicals impact the receiving waters depends largely on the type of receiving

water. For example, if the receiving waters have a low baseflow and highly variable flow rates,

the habitat and geomorphology will be very sensitive to significant changes in the hydrologic

regime. However, if the receiving waters have a high baseflow, the sensitivity to changes in

flow rate will be much less and the primary problems will likely be chemical in nature. Thus, it

is important to address impacts on a site-specific basis. 

Downstream Areas. A definition of the downstream area can be somewhat nebulous. (A

definition of the aerial extent of “downstream areas” is something that needs to be developed in

follow-up studies.) However, consideration of this area is important. For example, use of peak

discharge criteria may directly control the local area impacts and impacts to the point at which
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flow enters the receiving waters. If the watershed being considered is combined with other

downstream watersheds and all use peak discharge control without controlling runoff volume,

there can be an increase in flooding due to superposition of long duration peak flows exiting the

numerous reservoirs (Smiley and Haan, 1976). This increased discharge can negatively impact

channel geomorphology, habitat, and riparian areas. 

Another important issue related to construction is the fraction of the watershed under

construction at any one time. One argument about the relative importance of the construction

phase versus the post-construction phase is that the construction phase is short-lived and the

impact may be reversible after the site has stabilized. While this argument may have some

validity on the local area, it is invalid when considering the downstream areas. On a larger

watershed under development, major construction may occur in the watershed for a long time,

with a potential long-term major cumulative impact. When considering the entire watershed, it

may be desirable to limit the area under construction at any one time to prevent exceeding some

threshold that would result in an irreversible impact. This indicates the need to conduct a

cumulative impact analysis on a river basin scale to evaluate the potential for such an impact to

occur. 

When considering area impacts, the following comments can be made about the strategies listed

above.

Strategy 1. No guarantees can be made that impacts would be controlled at any level unless the

design standards are highly conservative. This would result in overdesign for most situations so

that the standard would be adequate for all situations.

Strategy 2. This strategy should ensure control at the local level. Downstream, the impacts may

be positive or negative as a result of the control. Examples include the control of peak discharge

only in storm water runoff. Control of peak discharge on all construction areas at the local level

can result in increased peak discharge downstream (Smiley and Haan, 1976). These increases

result from detaining increased volumes of runoff resulting from urbanization and releasing them

at the predisturbed peak rate over a long period of time. 

Strategy 3. This approach should ensure control in both the local area and downstream areas.

Scale is very important to BMP effectiveness analyses. A given BMP may be quite effective in

controlling impacts nearby but have a significant negative impact when applied over a large area. 

In the final analysis, effectiveness should be evaluated at multiple scales before a decision is

made. This will require both local and watershed level analyses. 
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5.1.2.3 QUALITATIVE VERSUS QUANTITATIVE ASSESSMENT

In the assessments, the issue may be addressed on a qualitative or a quantitative basis. The

difference can be explained in the following manner, using water temperature as an example. It

is well known that turbidity impacts the depth of penetration of solar energy into a waterbody;

hence, turbidity impacts temperature. When evaluating the impact of standards on water

temperature, it is obvious that a TSS standard directly addresses water temperature because of

the impact of TSS on turbidity. Thus, a qualitative analysis would simply state that TSS

standards may impact water temperature, but give no degree to which the standard does impact

temperature. A quantitative analysis, however, would define the degree to which a given TSS

standard increased or decreased the impact of storm water TSS on temperature.

5.1.3 REVIEW OF HISTORICAL APPROACHES TO EROSION AND SEDIMENT

CONTROL

Most early sediment control was related to agriculture and was installed as a way to maintain our

natural resource base. On-site control was the primary emphasis, attempting to prevent erosion

rather than trap sediment. Strategies were developed to minimize exposure of bare soil to the

erosive power of rainfall and runoff, using aboveground cover management, residue

management, strip cropping, and terracing to limit the length of overland flow. Impacts to

receiving streams and downstream areas had not yet been identified as an issue. In the 1960s,

concern began to be expressed about the quantities of sediment in streams and reservoirs, and

sediment was first identified as a pollutant. Initially, the major focus of sediment control was on

the surface mining industry, with the passage of the Clean Water Act and then the Surface

Mining, Reclamation, and Control Act (SMRCA) (PL 95-87) (U.S. Congress, 1977). The first

approach taken to sediment control was a design standard, requiring a sediment detention basin

with a 24-hour detention time; TSS standards of 35 mg/L average and 70 mg/L peak were also

promulgated, but were not typically enforced. The U.S. Environmental Protection Agency

(USEPA) later evaluated the TSS standard and moved to a settleable solids standard of 0.5 ml/L,

based on a modeling effort that showed that it was not possible to trap fine sediments, but that a

0.5 ml/L settleable solids standard could be met with a reasonably sized sediment basin (Ettinger

and Lichty, 1979).

In the late 1960s and early 1970s, sediment in streams and waterways originating from urban

construction sites became an issue, which was then addressed in the Clean Water Act. EPA

developed a list of BMPs and standards for their construction. (USEPA, 1971). In general, these

standards were adopted from those of other agencies and were not based on studies related to

urban runoff. 

In 1987, the Clean Water Act was amended to include storm water discharges from urban areas. 

The Phase I NPDES Stormwater regulations were published in 1990, requiring all municipalities
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with Municipal Separate Storm Sewer System (MS4) serving populations over 100,000,

construction sites 5 acres and larger, and certain industrial sites to obtain a permit. The permit

required the development of a stormwater pollution prevention plan (SWPPP) that typically

included a storm water and sediment control plan. In 1999, the Phase II NPDES stormwater

regulations were published, extending permit coverage to construction sites of 1 acre or larger

and municipalities to 50,000 or 10,000 population if the density is more than 1,000 per square

mile. The regulations allow use of general permits in lieu of individual site or facility permits. 

The degree of oversight of construction varies widely among the states. 

In the last two decades, increased concern at the local level has been focused on sediment

pollution of streams and waterways, particularly originating from construction, while less

concern has been focused on the impacts of increased construction on storm water and chemical

production. Much of this government concern originated from the Phase I and Phase II NPDES

stormwater regulations. A number of states and their local agencies have developed standards

and BMPs for sediment control, most of which do not have a scientific basis, but were adopted

from other agencies. Some states, however, did conduct studies that gave their standards some

scientific basis. For example, Maryland evaluated its BMP standards in the 1980s by using

modeling techniques and the state changed its sediment basin standards to account for the

impacts of surface area on the trapping efficiency in sediment ponds. Based on typical soils in

the region and modeling studies, the state adopted a surface area to peak discharge ratio of 0.01

cfs/acre as a criterion (Barfield and Clar, 1985; McBurnie, 1990). Maryland was thus the first

state to use a design criterion that was related to the overflow rate. Other states also used some

of Maryland's results (Smolen et al., 1988). 

Recent efforts have moved closer to an effluent standard approach. South Carolina conducted a

detailed analysis and published regulations that required a trapping efficiency or settleable solids

standard (SCDHEC, 1995). In addition, results from a detailed model were used to develop

simplified design aids (Hayes and Barfield, 1995; Holbrook et al., 1998). Some municipalities

are following suit to develop scientifically based standards of their own. For example, in 1998

Louisville, Kentucky (Hayes et al., 2001) developed standards and design aids for their storm

water and sediment control, following the example of South Carolina.

There are no analogs in which the integrated approach to storm water and sediment control have

been used on construction sites. The closest analog is the Cumulative Hydrologic Impact

Analysis (CHIA) required in surface mining by the SMRCA. SMRCA requires each applicant

for a surface mining permit to conduct a hydrologic impact analysis. Subsequently, the

regulatory authority is required to conduct a CHIA for the entire watershed. It should be pointed

out that although a CHIA is required, it is seldom undertaken on a scale that is useful. 

Many of the advances in sediment control have been based on the capability to predict, a priori,

the ability of a given design to meet a standard. For example, when the settleable solids standard
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was developed for surface mining, most regulatory authorities adopted it, with the requirement

that permit applicants would demonstrate through the use of widely accepted computer models,

that the proposed design would meet the settleable solids standard. 

Most of the early work in modeling sediment production stemmed from efforts in the 1950s to

develop a soil loss equation that would apply to the entire nation and allow evaluation of

alternative erosion control practices. This led to the relationship known as the Universal Soil

Loss Equation (USLE) (Wischmeier and Smith, 1965) and its subsequent derivative, the Revised

USLE (RUSLE) (Renard et al., 1994). These efforts focus on erosion control; thus, the

relationships do not predict sediment yield. A flurry of efforts were addressed in the late 1970s

and early 1980s leading to the development of sediment yield relationships such as yielding the

Modified USLE (MUSLE) by Williams (Williams, No Date), the CREAMS model (Knisel,

1980), and SEDIMOT II (Wilson et al., 1982), and its derivatives. The MUSLE and CREAMS

models did not include methods to evaluate the impact of sediment trapping structures, but

SEDIMOT II contained relationships developed at the University of Kentucky to predict the

impact of reservoirs (Ward et al., 1977; Wilson et al., 1984), check dams (Hirschi, 1981), and

vegetative filter strips (Hayes et al., 1984). The MUSLE and SEDIMOT II models were based

on single storms while the CREAMS model was based on continuous simulation modeling. 

Details on these models can be found in Haan et al. (1994).

More recently, modeling has improved, resulting in several new relationships. The WEPP

watershed model is one example of a continuous simulation approach. It includes computational

procedures for a wide variety of sediment control structures (Lindley et al., 1998). Another

example of a single storm-based model is SEDIMOT III (Barfield et al., 1996), which modifies

the earlier SEDIMOT II model to include channel erosion routines and a wide variety of

sediment control techniques. A significant drawback in the SEDIMOT III and WEPP models is

that they do not have a good technique for predicting the impact of filter fence, which is the most

common technique used today for sediment control.

Concerns for changes in geomorphology resulting from flow changes have resulted in several

modeling approaches. Early efforts were focused on what is known as the regime theory, in

which changes in channel property are linked, qualitatively, to changes in flow. Examples

include models of Lane (1955) and Schumm (1977). In addition, some statistically based

models were developed, but they are not universally applicable (Blench, 1970; Simons and

Albertson, 1960). More recently, models have been developed using physically based concepts

to predict changes in geomorphology as related to changes in flow. The models of Chang (1988)

are good examples. It is possible to predict, to a limited extent, the change in channel properties

as impacted by changes in flow. 

The impact of changes in flow and geomorphology on habitat is one major area where

information is lacking. Although this deficiency can be addressed in a qualitative manner, it is
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not possible to predict quantitatively how a given change in geomorphology will impact habitat. 

Additional information is needed to develop a strategy based on the integrated assessment

approach.

5.1.4 GOALS, CONTROL STRATEGIES, CRITERIA, AND STANDARDS

5.1.4.1 GOALS, CONTROL STRATEGIES, CRITERIA, AND STANDARDS:

HOW THEY RELATE

The relationship between goals, control strategies, criteria, and standards can sometimes be

confusing. For the purposes of the discussion on construction BMPs, the following definitions

will be used.

Goal. The overarching objective of having a storm water, sediment, and pollution control

program is known as the goal. It is what the program is trying to achieve. All BMPs should

relate to that goal. As stated earlier, the goal of this program is to minimize the impact of

construction on receiving water and downstream areas. The impacts of concern are identified in

the Environmental Assessment.

Control Strategies. The methods by which the regulatory agency tries to achieve the goal are

called control strategies. 

Criteria. The particular variables that are targeted by a given strategy are known as the criteria.

For example, if the strategy is to control impacts by limiting the discharge of sediment generated

to the receiving waters, then sediment becomes the criterion.

Standard. The specific variable chosen for the criteria and its numeric value is referred to as the

standard. For example, if the control strategy is to limit sediment discharge to the receiving

waters, the criterion is sediment, and the particular limiting variable and numeric value chosen is

a peak settleable solids concentration of 0.5 mg/L, then the standard would be a peak settleable

solids concentration of 0.5 mg/L. 

The relationship among goals, control strategies, criteria, and standards is shown graphically in

Figure 5-1. 
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Figure 5-1. Flow Diagram Showing Relationship Among Goals, Strategies, Criteria, and Standards
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5.1.4.2 LEVELS OF PERFORMANCE OR “HOW WELL DO THE

STRATEGIES WORK?”

Table 5-1 provides a description on the level of performance for the three strategies discussed in

sub-section 5.2.1.

Table 5-1. Description of Levels of Performance of Three Control Strategies

Level Description of Performance

0 No consideration of impact.

1 Performance defined by a design standard. No guarantee that the design will control the impact to a

desired level on the specific watershed. Example: reservoir volume standard for runoff control. 

2 Effluent standard based on controlling a single entity entering receiving waters. Control of the single

parameter will not guarantee that the desired protection will occur for receiving waters or

downstream impact. Example: controlling peak storm water discharge or peak TSS.

3 Effluent standard based on controlling two or more entities entering receiving waters, but not all

entities causing environmental impact. Example: controlling peak discharge and sediment, but not

storage volume or runoff volume. 

4 Effluent standards for all entities entering receiving waters and causing environmental impact. Even

controlling all quantities entering receiving waters will not guarantee that there are no undesired

downstream impacts. Example: Controlling runoff rate, runoff volume, peak discharge, and TSS in

receiving streams does not guarantee that there will be no undesirable biological impacts.

5 Control based on integrated evaluation of impacts on receiving stream and downstream.

5.1.4.3 STRATEGIES, CRITERIA, STANDARDS, AND ENFORCEMENT

The effectiveness of a given strategy, criterion, or standard is directly related to the ability of an

enforcement agency to enforce the rules. Thus, a given standard may theoretically provide

excellent protection to the environment, but be so difficult to enforce that it is less effective than

a less stringent standard that is enforceable. In general, the difficulty in enforcement increases as

the level of desired performance increases. An estimate of relative difficulty in enforcement is

given in Table 5-2 for the various levels of performance from Table 5-1. For example, it is

easiest to enforce the design standard, since enforcement is based entirely on reviewing plans

and inspection of the site to ensure that the plans are put into action properly. 

Important issues related to enforcement include the following:

• A priori demonstration by the best computational technology that the proposed design can

meet the standard. 
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• As-built inspections to verify that the installed practices match the approved plan.

• Self-monitoring of effluent in the case of effluent standards, with spot checks by the

regulatory authority to make sure that evaluations are being done properly.

• Evaluation of downstream impacts.

• Clearly defined rules for monitoring the effectiveness of a practice.

Table 5-2. Descriptions of Levels of Difficulty in Enforcement

Level of

Performance

from Table 1-1

Difficulty in

Enforcing

(Relative) Description of Difficulty

0 0 Nothing to enforce.

1 1 Enforcement consists of reviewing plans and ensuring proper installation

and maintenance.

2 2 Enforcement requires some monitoring and typically requires a 

preconstruction review of plans and submission of calculations showing

that the standard can be met.

3 2.5 Same as above except multiple variables.

4 2.5 Same as above.

5 5 Enforcement required some a priori demonstration of the expected flow

and concentration changes and their impact of the receiving waters and

downstream variables. In addition, routine monitoring of downstream

variables such as geomorphology, aquatic life, aesthetics, and riparian

zones would be required. 

A Priori Demonstration of Performance.

A priori demonstration that a given design can meet the standard is very important. Experience

with the surface mining industry indicates that a sediment control plan is no better than its

design. If the best computational technology indicates that the design will not meet the standard,

then field monitoring of the BMP is not likely to show that the standards are being achieved. 

Thus, it will be important to have scientifically based and verified computational technologies to

predict the performance of BMPs relative to meeting a specified standard. 

In recognition of this need the USEPA funded the development of the National Stormwater BMP

Database project by the Urban Water Resources Research Council of the American Society of

Civil Engineers (ASCE, 1999) in order to establish the state of the art of BMP performance with

respect to pollutant removal and peak discharge control (level 3). The database can be found at:
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http://www.bmpdatabase.org/. The ASCE project team prepared a report that contains several

different methods of evaluating BMP efficiency data. This report presents statistically based

approaches that involve conducting a statistical analysis to characterize inflow and outflow

EMCs, and then evaluates whether or not there is a statistically significant difference between

the two. The application of this approach in evaluating the data contained in the database has led

the study team to conclude that evaluating effluent quality is a good indicator of performance of

BMPs with respect to pollutant removal. A brief summary of the approach is provided in

Appendix A.

As-built Inspections

Another important issue related to enforcement is as-built inspections of installed practices. 

Although the rules may call for certification by an appropriately licensed professional, it is

important that the regulatory authority conduct routine inspections to ensure that the licensed

professionals are doing their job properly.

Monitoring

Finally, there are issues related to self-monitoring versus monitoring conducted by the regulatory

authority. The use of effluent standards would require some type of monitoring to ensure that

performance meets the standards. However, storm water and sediment control structures that

control flows are highly variable and temporally stochastic. This means that it is not possible to

plan ahead when the monitoring will occur. It will be necessary to have trained professionals to

conduct the monitoring. 

A monitoring methodology for BMPs should meet three criteria: (1) provide scientifically based

numbers to evaluate effectiveness, (2) be executable and sufficiently simple to allow the use of

trained technicians who would reasonably be available to do the monitoring, and (3) be adequate

to ensure that the desired standards are met without excessive sampling or analysis. The first

criterion could be met by providing clear documentation on the monitoring methodology that

specifies times, frequency, and location of sampling relative to storms, as well as clearly

articulated protocols for handling samples. The second criteria can be met by being sure that the

techniques proposed have actually been field applied by technicians in the monitoring business. 

The third criterion can be evaluated by an error analysis that determines the expected accuracy of

measurement as a function of number and frequency of sampling. 

Several possible criteria or standards have special measurement problems that should be

mentioned. These include criteria or standards based on trapping efficiency, and/or effluent TSS

and settleable solids (average or peak). The issues associated with these criteria are discussed

below. 
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Trapping Efficiency. Literature citations frequently include studies that attempt to measure

trapping efficiency by sampling one or more inflow and outflow concentrations (Barrett et al.,

1995). While this simplicity seems attractive, it is a grossly erroneous measure of trapping

efficiency. A correct definition of trapping efficiency is given in Equation 1:

Equation 1: TE = (Mi

 - Mo) / Mi

where: Mi is inflow total mass

Mo is outflow total mass

Mi is given by integrating the product of inflow concentration and inflow

rate over the duration of a hydrograph

or

Equation 2: Mi

 = Ci qi dt 

0

t D

∫

where: Ci is inflow concentration

qi is inflow flow rate

t is time

tD is the duration of the storm

Outflow total mass Mo is calculated by substituting the subscript o for i in Equation 2. Thus, to

monitor trapping efficiency correctly, it is necessary to measure both flow and concentration as a

function of time over the duration of both inflow and outflow. Such measurement is quite

difficult and time-consuming, requiring many samples.

Statistical Evaluation of Inflow/Outflow Data (mean, median, standard deviation,

coefficient of variance). To measure average or peak TSS, it is necessary to measure TSS in the

effluent over the duration of the outflow hydrograph as well as the flow rate. This requires that

multiple samples be taken and that the samples be centered around the peak discharge. The

ACSE database data analysis document has the ability, depending upon the number of samples

collected, to show a difference between various samples. Again, this is time-consuming and

difficult since the timing of an event and the timing of the peak discharge are not known a priori. 

The average concentration is a weighted concentration, using flow rate as a weighting function. 
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5.1.5 CONTROL TECHNIQUES, BMP SYSTEMS

5.1.5.1 EROSION CONTROL AND PREVENTION

5.1.5.1.1 PLANNING, STAGING, SCHEDULING

General Description

A construction sequence schedule is a specified work schedule that coordinates the timing of

land-disturbing activities and the installation of erosion and sediment control measures. The

goal of a construction sequence schedule is to reduce on-site erosion and off-site sedimentation

by performing land-disturbing activities and installing erosion and sediment control practices in

accordance with a planned schedule (Smolen et al., 1988). 

Construction site phasing involves disturbing only part of a site at a time to prevent erosion from

dormant parts (Claytor, 1997). Grading activities and construction are completed and soils are

effectively stabilized on one part of the site before grading and construction commence at

another part. This differs from the more traditional practice of construction site sequencing, in

which construction occurs at only one part of the site at the time, but site grading and other

site-disturbing activities typically occur simultaneously, 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 the following

(Claytor, 1997):

• Managing runoff separately in each phase.

• Determining whether water and sewer connections and extensions can be accommodated.

• Determining the fate of already completed downhill phases.

• 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 (USEPA, 2000).

Applicability

Construction sequencing can be used to plan earthwork and erosion and sediment control

activities at sites where land disturbances might affect water quality in a receiving waterbody. 
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Design and Installation Criteria

Construction sequencing schedules should, at a minimum, include the following (NCDNR, 1988;

MDE, 1994):

• The erosion and sediment control practices that are to be installed

• The principal development activities

• The measures that should be installed before other activities are started

• The compatibility with the general contract construction schedule
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Table 5-3 summarizes other important scheduling considerations in addition to those listed

above. 

Table 5-3. Scheduling Considerations for Construction Activities

Construction Activity Schedule Consideration

Construction survey stakeout Prior to initiating any construction activity a construction survey stakeout

should be conducted. The stakeout should identify the limits of disturbance,

and location of control structures, especially perimeter controls

Pre-construction meeting between owner,

contractor and regulatory agency

This meeting should take place before any construction activity begins at the

site. The survey stakeout is reviewed, especially the limits of disturbance and

location of controls

Construction access —entrance to site,

construction routes, areas designated for

equipment parking

This is the first land-disturbing activity. As soon as construction takes place,

stabilize any bare areas with gravel and temporary vegetation.

Clearing and grading required for the

installation of controls

In conjunction with the construction access, the clearing and grading required

for the installation of E&S controls should take place.

Sediment traps and barriers—basin traps,

silt fences, outlet protection

After construction site has been accessed, install principal basins, with the

addition of more traps and barriers as needed during grading.

Runoff control—diversions, perimeter

dikes, water bars, outlet protection

Install key practices after the installation of principal sediment traps and

before land grading. Additional runoff control measures may be installed

during grading.

Runoff conveyance system—stabilize

streambanks, storm drains, channels, inlet

and outlet protection, slope drains

If necessary, stabilize streambanks as soon as possible, and install principal

runoff conveyance system with runoff control measures. The remainder of

the systems may be installed after grading.

Land clearing and grading—site

preparation (cutting, filling, and grading;

sediment traps; barriers; diversions; drains;

surface roughening)

Implement major clearing and grading after installation of principal sediment

and key runoff control measures, and install additional control measures as

grading continues. Clear borrow and disposal areas as needed, and mark trees

and buffer areas for preservation.

Surface stabilization—temporary and

permanent seeding, mulching, sodding,

riprap

Immediately apply temporary or permanent stabilizing measures to any

disturbed areas where work has been either completed or delayed.

Building construction—buildings, utilities,

paving

During construction, install any erosion and sedimentation control measures

that are needed.

Landscaping and final

stabilization—adding top soil, trees, and

shrubs; permanent seeding; mulching;

sodding; riprap

This is the last construction phase. Stabilize all open areas, including borrow

and spoil areas, and remove and stabilize all temporary control measures.

Effectiveness

Construction sequencing can be an effective tool for erosion and sediment control because it

ensures that management practices are installed where necessary and when appropriate. 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 (Claytor, 1997). 
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Limitations

Weather and other unpredictable variables may affect construction sequence schedules. The

proposed schedule and a protocol for making changes resulting from unforseen problems should

be plainly stated in an applicable erosion and sediment control plan.

Maintenance

The construction sequence should be followed throughout the project, and the written erosion

and sediment control plan should be modified before any changes in construction activities are

executed. The plan can be updated if a site inspection indicates the need for additional erosion

and sediment control as determined by contractors, engineers, or developers. 

Cost

Construction sequencing is a low-cost BMP because it requires a limited amount of a

contractor’s time to provide a written plan for the coordination of construction activities and

management practices. Additional time might be needed to update the sequencing plan if the

current plan is not providing sufficient erosion and sediment control.

Although little research has been done to assess the costs of phasing versus conventional

construction costs, it is known that it will be to implement successful phasing for a larger project

(Claytor, 1997). 

5.1.5.1.2 VEGETATIVE STABILIZATION

Vegetation can be used during construction to stabilize and protect soil exposed to the erosive

forces of water, as well as during post-construction to provide a filtration mechanism for storm

water runoff pollutants. The following discussion refers to vegetative stabilization as a

construction BMP that stabilizes and protects soil from erosion. 

General Description

Vegetative stabilization measures employ plant material to protect soil exposed to the erosive

forces of water and wind. Selected vegetation can reduce erosion by more than 90 percent

(Fifield, 1999). Natural plant communities that are adapted to the site provide a self-maintaining

cover that is less expensive than structural alternatives. Plants provide erosion protection to

vulnerable surfaces by the following (Heyer, n.d.):

• Protecting soil surface from the impact of raindrops.

• Holding soil particles in place.
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• Maintaining the soil’s capacity to absorb water.

• Using living root systems to hold soil in place, increasing overall bank stability. 

• Directing flow velocity away from the streambank.

• Acting as a buffer against abrasive transported materials.

• Causing sediment deposition, which reduces sediment load and reestablishes the streambank.

The designer should be aware of and respond to local conditions that may influence the

development of vegetative stabilization measures. As with any planting design, climate,

maintenance practices, the availability of plant material (including native species), and many

other factors will influence such considerations as plant or seed mix selection, installation

methods, and project scheduling. 

Slope Stabilization. On slopes, the goal of vegetative stabilization is not only to reduce surface

erosion but also to prevent slope failure. Vegetation should provide dense coverage to protect

soils from the direct impact of precipitation and help intercept runoff. A variety of plants should

be used to provide root systems that are distributed throughout all levels of the soil, increasing

slope shear strength and giving plants a greater ability to remove soil moisture. Uniform mats of

shallow rooting plants should be avoided because, while such plants may increase runoff

infiltration, they cannot remove soil moisture beyond the surface level, leaving slopes potentially

saturated and prone to slippage. Shallow, interlocking root systems may also increase the size of

a soil slippage by holding together and pulling down a larger area of slope after a small section

has given way. Large trees that have become unstable may also pull down slopes and should be

removed. Using plants with low water requirements can reduce the potential for soil saturation

from irrigation. 

Swale Stabilization. On swales, the goal of vegetative stabilization is to prevent erosion within

the swale, where runoff is concentrated and flows at higher velocities. If natural stream channels

are involved, vegetation with deep root systems should be preserved, or if absent, planted above

the channel to help maintain the channel banks. More information is provided in the subsequent

section dealing with grass-lined swales. 

Surface Stabilization. On large, flat areas, the goal of vegetative stabilization is to reduce the

loss of surface soil from sheet erosion. Vegetation should provide complete coverage to reduce

the force of precipitation, which can shift soil particles to seal openings in the soil, reducing

infiltration and increasing runoff. Vegetation should also provide many stem penetrations to

slow runoff and increase infiltration. Deep rooting plants are less critical for erosion control in

flat areas than on slopes because soils are not subject to the same forces that may cause slippage

on a slope. However, trees and shrubs can increase infiltration, lessening the buildup of runoff,

and transpire large volumes of water, reducing soil saturation. 
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In areas susceptible to wind erosion, the goal of vegetative stabilization is to establish direct

protection of the soil. Vegetation should provide dense and continuous surface cover. Binding

the soil deeply is generally not a requirement. The ideal vegetation for this purpose is grass,

which forms a mat of protection. In areas where the vegetation is developed, the grass generally

has high maintenance requirements. In less developed, open areas, unmown grass, including

perennial native species, can be used to provide protection. Trees and shrubs also can provide

protection from the wind. 

Shoreline Stabilization. In lakes and ponds, the goal of vegetative stabilization is to prevent

erosion of the shoreline. Wetland plants anchor the bottom of the lake or pond adjacent to the

shore and help dissipate the erosive energy of waves. An important consideration in planting

along shorelines is the need to establish favorable conditions for plant establishment and growth.

These include the proper grading of side slopes and the control of upland erosion to prevent the

buildup of silt and associated pollutants in the water. Designers should maintain awareness of

regulatory requirements that may influence vegetation projects in a wetland environment

(USAF, 1998).

Vegetation used for shoreline stabilization work should be native material selected on the basis

of strength, resiliency, vigor, and ability to withstand periodic inundation. Woody vegetation

with short, dense, flexible tops and large root systems works well. Other important factors

include rapid initial growth, ability to reproduce, and resistance to disease and insects. 

According to Heyer, n.d., most streambank stabilization plantings have used various willows,

including black willow (Salix nigra), sandbar willow (S. interior), meadow willow (S.

petiolaris), heartleaf willow (S. rigida), and Ward willow (S. caroliniana). The size used

depends on the severity of the erosion and the type of bank to be stabilized. Whatever the size, it

is important to use dormant cuttings and to remove all lateral branches. Most tree revetment

projects used either eastern red cedar (Juniperus virginiana) or hardwoods such as northern pin

oak (Quercus ellipsoidalis). Important suggestions include the following: 

• Choose trees with many limbs and branches to trap as much sediment as possible.

• Select decay-resistant trees.

• Use recently cut trees—dead trees are more brittle and likely to break apart.

• The tree size-diameter of the tree crown should be about two-thirds of the height of the

eroding bank.

• Cut off any trunk without limbs.

• Place the tree revetments overlapping, butt end pointing upstream.

• Begin and end revetments at stable points along the bank.
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• Choose an anchoring system according to the bank material to be stabilized and the weight of

the object to be anchored.

Vegetative measures for streambank stabilization offer an alternative to structural measures and

are becoming well known as bioengineering techniques for streambanks. Utilizing vegetative

material for streambank stabilization could be the first step in the reestablishment of the riparian

forest, which is essential for long-term stability of the streamside and floodplain areas. Each site

must be evaluated separately as to the feasibility of using natural material (Heyer, n.d.).

Vegetative streambank stabilization, with the goal to protect streambanks from the erosive forces

of flowing water, is generally applicable where bankfull flow velocity does not exceed 6 ft/sec

and soils are erosion resistant (Smolen, 1988). Table 5-4 includes general guidelines for

maximum allowable velocities in streams to be protected by vegetation.

Table 5-4. Conditions Where Vegetative Streambank Stabilization Is Acceptable

Frequency of Bankfull Flow

Maximum Allowable Velocity for

Highly Erodible Soil

Maximum Allowable Velocity for

Erosion-Resistant Soil

> 4 times/yr 4 ft/sec 5 ft/sec

1 to 4 times/yr 5 ft/sec 6 ft/sec

< 1 time/yr 6 ft/sec 6 ft/sec

Source: Smolen, 1988.

Temporary Vegetative Stabilization. Temporary vegetative cover such as rapidly growing

annuals and legumes can be used to establish a temporary vegetative cover. Such covers are

recommended for areas that (Fifield, 1999):

• Will not be brought to final grade within 30 days or are likely to be redisturbed.

• Require seeding of cut and fill slopes under construction.

• Require stabilization of soil storage areas and stockpiles.

• Require stabilization of temporary dikes, dams, and sediment containment systems.

• Require development of cover or nursery crops to assist with establishing perennial grasses.

Examples of temporary vegetation include wheat, oats, barley, millet, and sudan. Temporary

seeding may not be effective in arid or semi-arid regions where seasonal conditions (lack of

moisture) prevent germination. It may be necessary to use a mixture of warm and cool season

grasses to ensure germination. Mulching and geotextiles can be used to help provide temporary

stabilization with vegetation, particularly in situations where establishing cover may be difficult. 
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Permanent Vegetative Stabilization. Permanent vegetative cover such as a perennial grass or a

legume cover can be used to establish a permanent vegetative cover. Permanent vegetation is

recommended for (Fifield, 1999)

• Final graded or cleared areas where permanent vegetative cover is needed to stabilize the soil

• Slopes designated to be treated with erosion control blankets

• Grass-lined channels or waterways designed to be channel liners

The following sub-sections discuss the various types or means of providing vegetative

stabilization.

5.1.5.1.2.1 GRASS-LINED CHANNELS

General Description

Grass-lined channels, or swales, convey storm water runoff through a stable conduit. Vegetation

lining the channel reduces the flow velocity of concentrated runoff. Grassed channels are

usually not designed to control peak runoff loads by themselves and are often used in

combination with other BMPs such as subsurface drains and riprap stabilization. 

Applicability

Grassed channels should be used in areas where erosion-resistant conveyances are needed, such

as in areas with highly erodible soils and slopes of less than 5 percent. They should be installed

only where space is available for a relatively large cross-section. Grassed channels have a

limited ability to control runoff from large storms and should not be used in areas where velocity

exceeds 5 feet per second unless they are on erosion-resistant soils with dense groundcover at the

soil surface. 

Design and Installation Criteria

Because of their ease of construction and low cost, vegetated-lined waterways are frequently

used on diversion and collection ditches. USDA’s Soil Conservation Service’s (SCS)

Engineering Field Manual (1979) recommends the following maximum permissible velocities

for individual site conditions shown in Table 5-5.
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Table 5-5. Maximum Permissible Velocities for Individual Site 

Conditions for Grass Swales

Site Location Velocity

Areas where only a sparse cover can be established or

maintained because of shale, soils, or climate 3.00 ft/sec (0.91 m/sec)

If the vegetation is to be established by seeding 3.00 to 4.00 ft/sec (0.91 to 1.22 m/sec)

Areas where a dense, vigorous sod is obtained quickly

or where the runoff can diverted out of the waterway

while the vegetation is being established 4.00 to 5.00 ft/sec (1.22 to 1.52 m/sec)

Source: USDA, 1979

Grassed waterways typically begin eroding in the invert of the channel if the velocity exceeds

the sheer strength of the vegetation soil interface. Once the erosion process has started, it will

continue until an erosion-resistant layer is encountered. If erosion of a channel bottom is

occurring, rock or stone should be placed in the eroded area or the design should be changed

(UNEP, 1994).

Grassed waterways on construction land must be able to carry peak runoff events from snowmelt

and rainstorms (in some areas limited to up to 1 cubic meter of water per second). The size of the

waterway depends on the size of the area to be drained. A typical grassed waterway cross-section

is parabolic-shaped with a nearly flat-bottomed channel, a bottom width of 3 m and channel

depth of at least 30 cm. Side slopes usually rise about 1 m for every 10 m horizontal distance but

may be as steep as a 1 m rise for every 2 m of horizontal distance. The waterway should follow

the natural drainage path if possible (Vanderwel, 1998). The design should be site-specific and

use available, well-established procedures. 

Lined channels are a means of dropping water to lower elevations along steep parts of a

waterway. Those portions of the waterway are precisely shaped and carefully lined with heavyduty erosion control matting, a type of geotextile product. The lining is covered with a layer of

soil and seeded to grass. The resulting channel is highly resistant to erosion. Lined channels are

appropriate for waterways that only carry water occasionally and have slopes of up to 10 percent.

Companies that sell geotextile products provide detailed information on installation of their

products (Vanderwel and Abday, 1998). The design should be site-specific, using wellestablished procedures. No standard procedure is available for evaluating the effectiveness of

geotextile liners for pollutant removal. 

Grass-lined channels should be sited in accordance with the natural drainage system and should

not cross ridges. The channel design should not have sharp curves or significant changes in

slope. The channel should not receive direct sedimentation from disturbed areas and should be

sited only on the perimeter of a construction site to convey relatively clean storm water runoff. 

They should be separated from disturbed areas by a vegetated buffer or other BMP to reduce

sediment loads. 
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Although exact design criteria should be based on local conditions, basic design

recommendations for grassed channels include the following:

• Construction and vegetation of the channel should occur before grading and paving activities

begin.

• Design velocities should be less than 5 ft/sec.

• Geotextiles can be used to stabilize vegetation until it is fully established.

• Covering the bare soil with sod or geotextiles can provide reinforced storm water

conveyance immediately.

• Triangular-shaped channels should be used with low velocities and small quantities of

runoff; parabolic grass channels are used for larger flows and where space is available;

trapezoidal channels are used with large flows of low velocity (low gradient).

• Outlet stabilization structures might be needed if the runoff volume or velocity has the

potential to exceed the capacity of the receiving area.

• Channels should be designed to convey runoff from a 10-year storm without erosion.

• The sides of the channel should be sloped less than 3:1, with V-shaped channels along roads

sloped 6:1 or less for safety.

• All trees, bushes, stumps, and other debris should be removed during construction.

Effectiveness

Grass-lined channels can effectively transport storm water from construction areas if they are

designed for expected flow volumes and velocities and if they do not receive sediment directly

from disturbed areas. The primary function is to carry the flow at a higher velocity without

eroding or overtopping the channel. 

Limitations

Grassed channels, if improperly installed, can alter the natural flow of surface water and have

adverse impacts on downstream waters. Additionally, if the design capacity is exceeded by a

large storm event, the vegetation might not be sufficient to prevent erosion and the channel

might be destroyed. Clogging with sediment and debris reduces the effectiveness of grass-lined

channels for storm water conveyance.
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Maintenance

Maintenance requirements for grass channels are relatively minimal. During the vegetation

establishment period, the channels should be inspected after every rainfall. Other maintenance

activities that should be carried out after vegetation is established are mowing, litter removal,

and spot vegetation replacement. The most important objective in the maintenance of grassed

channels is the maintaining of a dense and vigorous growth of turf. Periodic cleaning of

vegetation and soil buildup in curb cuts is required so that water flow into the channel is

unobstructed. During the growing season, channel grass should be cut no shorter than the level

of design flow, and the cuttings should be removed promptly. 

Cost

Costs of grassed channels range according to depth, with a 1.5-foot-deep, 10-foot-wide grassed

channel estimated at between $6,395 and $17,075 per trench, while a 3.0-foot-deep, 21-footwide grassed channel is estimated at $12,909 to $33,404 per trench (SWRPC, 1991).

As an alternative cost approximation, grassed channel construction costs can be developed using

unit cost values. Shallow trenching (1 to 4 feet deep) with a backhoe in areas not requiring

dewatering can be performed for $4 to $5 per cubic yard of removed material (R. S. Means,

2000). Assuming no disposal costs (i.e., excavated material is placed on either side of the

trench), only the cost of fine grading, soil treatment, and grassing (approximately $2 per square

yard of earth surface area) should be added to the trenching cost to approximate the total

construction cost. Site-specific hydrologic analysis of the construction site is necessary to

estimate the channel conveyance requirement, however, it is not unusual to have flows on the

order of 2 to 4 cfs per acre served. For channel velocities between 1 and 3 feet per second, the

resulting range in the channel cross-section area can be as low as 0.67 square foot per acre

drained to as high as 4 square feet per acre. If the average channel flow depth is 1 foot, then the

low estimate for grassed channel installation is $0.27 per square foot of channel bottom per acre

served per foot of channel length. The high estimate is $1.63 per square foot of channel bottom

per acre served per foot of channel length.

5.1.5.1.2.2 SEEDING

General Description

Permanent seeding, is used to control runoff and erosion on disturbed areas by establishing

perennial vegetative cover from seed. It is used to reduce erosion, decrease sediment yields from

disturbed areas, and provide permanent stabilization. This practice is both economical and

adaptable to different site conditions, and it allows selection of the most appropriate plant

materials. Seeding is a best management practice that is particularly susceptible to local

conditions such as the climatic conditions, physical and chemical characteristics of the soil,

topography, and time of year. 
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Applicability

Permanent seeding is well-suited in areas where permanent, long-lived vegetative cover is the

most practical or most effective method of stabilizing the soil. Permanent seeding can be used

on roughly graded areas that will not be regraded for at least a year. Vegetation controls erosion

by protecting bare soil surfaces from displacement by raindrop impacts and by reducing the

velocity and quantity of overland flow. The advantages of seeding over other means of

establishing plants include lower initial costs and labor inputs. 

Design and Installation Criteria

Areas to be stabilized with permanent vegetation must be seeded or planted 1 to 4 months after

the final grade is achieved unless temporary stabilization measures are in place. Successful plant

establishment can be maximized with proper planning; consideration of soil characteristics;

selection of plant materials that are suitable for the site; adequate seedbed preparation, liming,

and fertilization; timely planting; and regular maintenance. Climate, soils, and topography are

major factors that dictate the suitability of plants for a particular site. The soil on a disturbed site

might require amendments to provide sufficient nutrients for seed germination and seedling

growth. The surface soil must be loose enough for water infiltration and root penetration. Soil

pH should be between 6.0 and 6.5 and can be increased with liming if soils are too acidic. Seeds

can be protected with mulch to retain moisture, regulate soil temperatures, and prevent erosion

during seedling establishment. 

Seedbed preparation is critical in established vegetation. Spraying seeds on a scraped slope will

generally not provide satisfactory results. Typical seedbed preparation will begin with a soil test 

to determine the amount of lime or fertilizer that should be added. In addition, tillage should be

performed that will break up clods so that seed contact can be established. When the seed is

applied, it should be covered and lightly compacted. An appropriate natural or synthetic mulch is

recommended to provide surface stabilization until the vegetation is established. In addition to

providing surface stabilization, the mulch will also retard evaporation and encourage rapid

growth. A suitable tack to hold the mulch may be necessary if the mulch is not otherwise

anchored. Mulches are covered in a subsequent sub-section.

Depending on the amount of use permanently seeded areas receive, they can be considered highor low-maintenance areas. High-maintenance areas are mowed frequently, limed and fertilized

regularly, and either (1) receive intense use (for example, athletic fields) or (2) require

maintenance to an aesthetic standard (for example, home lawns). Grasses used for highmaintenance areas are long-lived perennials that form a tight sod and are fine-leaved. 

High-maintenance vegetative cover is used for homes, industrial parks, schools, churches, and

recreational areas.

Low-maintenance areas are mowed infrequently or not at all and do not receive lime or fertilizer

on a regular basis. Plants must be able to persist with minimal maintenance over long periods of
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time. Grass and legume mixtures are favored for these sites because legumes fix nitrogen from

the atmosphere. Sites suitable for low-maintenance vegetation include steep slopes, streambanks

or channel banks, some commercial properties, and "utility" turf areas such as road-banks.

Effectiveness

Seeding that results in a successful stand of grass has been shown to remove between 50 and 100

percent of total suspended solids from storm water runoff, with an average removal of 90 percent

(USEPA, 1993). 

Limitations

The effectiveness of permanent seeding can be limited because of the high erosion potential

during establishment, the need to reseed areas that fail to establish, limited seeding times

depending on the season, and the need for stable soil temperature and soil moisture content

during germination and early growth. Permanent seeding does not immediately stabilize

soils—temporary erosion and sediment control measures should be in place to prevent off-site

transport of pollutants from disturbed areas. Use of mulches and/or geotextiles may improve the

likelihood of successfully establishing vegetation. 

Maintenance

Grasses should emerge within 4 to 28 days and legumes 5 to 28 days after seeding, with legumes

following grasses. A successful stand should exhibit the following:

• Vigorous dark green or bluish green seedlings—not yellow

• Uniform density, with nurse plants, legumes, and grasses well intermixed

• Green leaves—perennials remaining throughout the summer, at least at the plant bases

Seeded areas should be inspected for failure, and necessary repairs and reseeding should be

made as soon as possible. If a stand has inadequate cover, the choice of plant materials and

quantities of lime and fertilizer should be reevaluated. Depending on the condition of the stand,

areas can be repaired by overseeding or reseeding after complete seedbed preparation. If the

timing is bad, an annual grass seed can be overseeded to temporarily thicken the stand until a

suitable time for seeding perennials. Consider seeding temporary, annual species if the season is

not appropriate for permanent seeding. If vegetation fails to grow, the soil should be tested to

determine whether low pH or nutrient imbalances are responsible. Local NRCS or county

extension agents can also be contacted for seeding and soil testing recommendations. 

On a typical disturbed site, full plant establishment usually requires refertilization in the second

growing season. Soil tests should be used to determine whether more fertilizer needs to be
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added. Do not fertilize cool season grasses in late May through July. Grass that looks yellow

may be nitrogen deficient. Nitrogen fertilizer should not be used if the stand contains more than

20 percent legumes. 

Cost 

Seeding costs range from $200 to $1,000 per acre and average $400 per acre. Maintenance costs

range from 15 to 25 percent of initial costs and average 20 percent (USEPA, 1993). R. S. Means

(2000) indicates the cost of mechanical seeding to be approximately $900 per acre, and

demonstrates that the coverage cost varies with the seed type, seeding approach and scale (total

acreage to be seeded). For example, hydro or water-based seeding for grass is estimated to be

$700 per acre but seeding of “field” grass species is only $540 per acre (Costs include materials,

labor, and equipment, with profit and overhead). If surface preparation is required, then the

installation costs increase. R. S. Means suggests the cost of fine grading, soil treatment, and

grassing is approximately $2 per square yard of earth surface area.

5.1.5.1.2.3 SODDING

General Description

Sodding is a permanent erosion control practice that involves laying a continuous cover of grass

sod on exposed soils. In addition to stabilizing soils, sodding can reduce the velocity of storm

water runoff. Sodding can provide immediate vegetative cover for critical areas and stabilize

areas that cannot be vegetated by seed. It can also stabilize channels or swales that convey

concentrated flows and reduce flow velocities. While sodding is not as dependent as seeding on

local conditions, it does depend on soil and climatic conditions to be successful. Capability to

water immediately after installation and occasionally until establishment is generally beneficial. 

Applicability

Sodding is appropriate for any graded or cleared area that might erode, requiring immediate

vegetative cover. Locations particularly well-suited to sod stabilization are:

• Waterways and channels carrying intermittent flow

• Areas around drop inlets that require stabilization

• Residential or commercial lawns and golf courses where prompt use and aesthetics are

important

• Steeply sloped areas
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Design and Installation Criteria

Sodding eliminates the need for seeding and mulching and produces more reliable results with

less maintenance. Sod can be laid during times of the year when seeded grasses can fail. The

sod must be watered frequently within the first few weeks of installation. Some seedbed

preparation is recommended, including smoothing to provide contact between the sod and the

soil surface and soil testing to determine liming and fertilizer application rates. Since sod

provides instantaneous cover, mulches are not typically recommended, but anchoring may be

appropriate on steep slopes. 

The type of sod selected should be composed of plants adapted to site conditions. Sod

composition should reflect environmental conditions as well as the function of the area where

the sod will be laid. The sod should be of known genetic origin and be free of noxious weeds,

diseases, and insects. The sod should be machine cut at a uniform soil thickness of 15 to 25 mm

at the time of establishment (this does not include top growth or thatch). Soil preparation and

addition of lime and fertilizer may be needed—soils should be tested to determine whether

amendments are needed. Sod should be laid in strips perpendicular to the direction of water flow

and staggered in a brick-like pattern. The corners and middle of each strip should be stapled

firmly. Jute or plastic netting may be pegged over the sod for further protection against washout

during establishment. 

Areas to be sodded should be cleared of trash, debris, roots, branches, stones, and clods larger

than 2 inches in diameter. Sod should be harvested, delivered, and installed within a period of

36 hours. Sod not transplanted within this period should be inspected and approved prior to its

installation. 

Limitations

Compared to seed, sod is more expensive and more difficult to obtain, transport, and store. Care

must be taken to prepare the soil and provide adequate moisture before, during, and after

installation to ensure successful establishment. If sod is laid on poorly prepared soil or

unsuitable surface, the grass will die quickly because it is unable to root. Sod that is not

adequately irrigated after installation may cause root dieback because grass does not root rapidly

and is subject to drying out.

Effectiveness

Sod has been shown to remove between 98 and 99 percent of total suspended solids in runoff

(USEPA, 1993). It is therefore a highly effective management practice for erosion and sediment

control. 
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Maintenance

Watering is very important to maintain adequate moisture in the root zone and to prevent

dormancy, especially within the first few weeks of installation, until it is fully rooted. Mowing

should not result in the removal of more than one-third of the shoot. Grass height should be

maintained at between 2 and 3 inches. After the first growing season, sod might require

fertilization or liming. Permanent, fine turf areas require yearly maintenance fertilization. 

Warm-season grass should be fertilized in late spring to early summer, and cool-season grass in

late winter and again in early fall.

Cost 

Average construction costs of sod average $0.20 per square foot and range from $0.10 to $1.10

per square foot; maintenance costs are approximately 5 percent of installation costs (USEPA,

1993). R. S. Means (2000) indicates the sodding ranges between $250 and $750 per 1000 square

feet for 1" deep bluegrass sod on level ground, depending on the size of the area treated (unit

costs value are for orders over 8,000 square feet and less than 1000 square feet, respectively).

Bent grass sod values range between $350 and $500 per 1000 square feet, again the lower value

is more likely for most construction sites because it is for large area applications. (Costs include

materials, labor, and equipment, with profit and overhead). 

5.1.5.1.2.4 MULCHING

General Description

Mulching is a temporary erosion control practice in which materials such as grass, hay, wood

chips, wood fibers, straw, or gravel are placed on exposed or recently planted soil surfaces. 

Mulching is highly recommended as a stabilization method and is most effective when anchored

in place until vegetation is well established. In addition to stabilizing soils, mulching can reduce

the velocity of storm water runoff. When used in combination with seeding or planting,

mulching can aid plant growth by holding seeds, fertilizers, and topsoil in place; by preventing

birds from eating seeds; by retaining moisture; and by insulating plant roots against extreme

temperatures. 

Mulch mattings are materials such as jute or other wood fibers that are formed into sheets and

are more stable than loose mulch. They can also be easily unrolled during the installation

process and are particularly useful in steeper areas or in channels. Netting can be used to

stabilize soils while plants are growing, although netting does not retain moisture or insulate

against extreme temperatures. Mulch binders consist of asphalt or synthetic materials that are

sometimes used instead of netting to bind loose mulches but have been found to have limited

usefulness. 
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June 2002 5-30

Applicability

Mulching is often used in areas where temporary seeding cannot be used because of

environmental constraints. Mulching can provide immediate, effective, and inexpensive erosion

control. On steep slopes and critical areas such as waterways, mulch matting is used with

netting or anchoring to hold it in place. Mulches can be used on seeded and planted areas where

slopes are steeper than 2:1 or where sensitive seedlings require insulation from extreme

temperatures. 

Design and Installation Criteria

When possible, organic mulches should be used for erosion control and plant material

establishment. Suggested materials include loose straw, netting, wood cellulose, or agricultural

silage. All materials should be free of seed, and loose hay or straw should be anchored by

applying tackifier, stapling netting over the top, or crimping with a mulch crimping tool. 

Materials that are heavy enough to stay in place do not need anchoring (for example, gravel). 

Steepness of the slope will also affect the extent of anchoring the mulch. Other examples

include hydraulic mulch products with 100 percent post-consumer paper content, yard trimming

composts, and wood mulch from recycled stumps and tree parts. Inorganic mulches such as pea

gravel or crushed granite can be used in unvegetated areas. 

Mulches may or may not require a binder, netting, or tacking. All straw and loose materials

must have a binder to hold them in place. Mulch materials that float away during storms can

clog drainage ways and lead to flooding. The extent of binding depends on the type of mulch

applied. Effective use of netting and matting material requires firm, continuous contact between

the materials and the soil. If there is no contact, the material will not hold the soil and erosion

will occur underneath the material. Grading is not necessary before mulching. 

There must be adequate coverage, or erosion, washout, and poor plant establishment will result. 

If an appropriate tacking agent is not applied, or if it is applied in an insufficient amount, mulch

will not withstand wind and runoff. The channel grade and liner must be appropriate for the

amount of runoff, or the channel bottom will erode. Also, hydromulch should be applied in

spring, summer, or fall to prevent deterioration of the mulch before plants can become

established. Table 5-6 presents guidelines for installing mulches, but local conditions may

warrant additional requirements. 
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June 2002 5-31

Table 5-6. Typical Mulching Materials and Application Rates

Material

Rate per

Acre Requirements Notes

Organic Mulches

Straw 1-2 tons

Dry, unchopped, unweathered; avoid

weeds.

Spread by hand or machine; must be

tacked or tied down.

Wood fiber or wood

cellulose 0.5-1 ton

Use with hydroseeder; may be used to

tack straw. Do not use in hot, dry

weather.

Wood chips 5-6 tons Air dry. Add fertilizer N, 12 lb/ton.

Apply with blower, chip handler, or

by hand. Not for fine turf areas.

Bark 35 yd3

Air dry, shredded or hammermilled,

or chips.

Apply with mulch blower, chip

handler, or by hand. Do not use

asphalt tack.

Nets and Mats

Jute net Cover area

Heavy, uniform; woven of single jute

yarn. Used with organic mulch. Withstands water flow.

Excelsior 

(wood fiber) mat Cover area

Fiberglass roving 0.5-1 ton 

Continuous fibers of drawn glass

bound together with a non-toxic

agent.

Apply with compressed air ejector.

Tack with emulsified asphalt at a rate

of 25-35 gal/1,000 ft2.

Effectiveness

Mulching effectiveness varies with the type of mulch used and local conditions such as rainfall

and runoff amounts. Percent soil loss reduction for different mulches ranges from 53 to 99.8

percent used and associated water velocity reductions range from 24 to 78 percent (Harding,

1990). Table 5-7 shows soil loss and water velocity reductions for different mulch treatments.
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June 2002 5-32

Table 5-7. Measured Reductions in Soil Loss for Different Mulch Treatments

Mulch characteristics Soil loss

reduction

(%)

Water velocity reduction

(%)relative to bare soil

100% wheat straw/top net 97.5 73

100% wheat straw/two nets 98.6 56

70% wheat straw/30% coconut

fiber 98.7 71

70% wheat straw/30% coconut

fiber 99.5 78

100% coconut fiber 98.4 77

Nylon monofilament/two nets 99.8 74

Nylon

monofilament/rigid/bonded 53.0 24

Vinyl

monofilament/flexible/bonded 89.6 32

Curled wood fibers/top net 90.4 47

Curled wood fibers/two nets 93.5 59

Antiwash netting(jute) 91.8 59

Interwoven paper and thread 93.0 53

Uncrimped wheat straw–2,242

kg/ha 84.0 45

Uncrimped wheat straw–4,484

kg/ha 89.3 59

Source: Harding, 1990, as cited in USEPA, 1993.

Limitations

Mulching, matting, and netting might delay seed germination because the cover changes soil

surface temperatures. The mulches themselves are subject to erosion and may be washed away

in a large storm if not sufficiently anchored with netting or tacking. Maintenance is necessary to

ensure that mulches provide effective erosion control. 
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Maintenance

Mulches must be anchored to resist wind displacement. Netting should be removed when

protection is no longer needed and disposed of in a landfill or composted. Mulched areas should

be inspected frequently to identify areas where mulch has loosened or been removed, especially

after rain storms. Such areas should be reseeded (if necessary) and the mulch cover replaced

immediately. Mulch binders should be applied at rates recommended by the manufacturer. If

washout, breakage, or erosion occurs, surfaces should be repaired, reseeded, and remulched, and

new netting should be installed. Inspections should be continued until vegetation is firmly

established.

Cost

The costs of seed and mulch average $1,500 per acre and range from $800 to $3,500 per acre

(USEPA, 1993). R. S. Means (2000) estimates the cost of power mulching to be $22.50 per

1000 square feet, for large volume applications. In addition, hydro- and mechanical seeding are

approximately $700 to $900 per acre. Coverage cost varies with the seed type, seeding approach,

and scale (total acreage to be seeded). For example, hydro or water-based seeding for grass is

estimated to be $700 per acre, but seeding of “field” grass species is only $540 per acre. (Costs

include materials, labor, and equipment, with profit and overhead.) If surface preparation is

required, then the installation costs increase. R. S. Means (2000) suggests the cost of fine

grading, soil treatment, and grassing is approximately $2 per square yard of earth surface area.

5.1.5.1.2.5 GEOTEXTILES

General Description

Geotextiles are porous fabrics also known as filter fabrics, road rugs, synthetic fabrics,

construction fabrics, or simply fabrics. Geotextiles are manufactured by weaving or bonding

fibers made from synthetic materials such as polypropylene, polyester, polyethylene, nylon,

polyvinyl chloride, glass, and various mixtures of these materials. As a synthetic construction

material, geotextiles are used for a variety of purposes such as separators, reinforcement,

filtration and drainage, and erosion control (USEPA, 1992). Some geotextiles are made of

biodegradable materials such as mulch matting and netting. Mulch mattings are jute or other

wood fibers that have been formed into sheets and are more stable than normal mulch. Netting

is typically made from jute, wood fiber, plastic, paper, or cotton and can be used to hold the

mulching and matting to the ground. Netting can also be used alone to stabilize soils while the

plants are growing; however, it does not retain moisture or temperature well.

Geotextiles can aid in plant growth by holding seeds, fertilizers, and topsoil in place. Fabrics are

relatively inexpensive for certain applications—a wide variety of geotextiles exist to match the

specific needs of the site.
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June 2002 5-34

Applicability

Geotextiles can be used for erosion control by using it alone. Geotextiles can be used as matting,

which is used to stabilize the flow of channels or swales or to protect seedlings on recently

planted slopes until they become established. Matting may be used on tidal or streambanks

where moving water is likely to wash out new plantings. They can also be used to protect

exposed soils immediately and temporarily, such as when active piles of soil are left overnight. 

Geotextiles are also used as separators. An example of such a use is geotextile as a separator

between riprap and soil. This “sandwiching” prevents the soil from being eroded from beneath

the riprap and maintaining the riprap’s base.

Design and Installation Criteria

Many types of geotextiles are available. Therefore, the selected fabric should match its purpose. 

State or local requirements, design procedures, and any other applicable requirements should be

considered. In the field, important concerns include regular inspections to determine whether

cracks, tears, or breaches are present in the fabric and appropriate repairs should be made. 

Effective netting and matting require firm, continuous contact between the materials and the soil. 

If there is no contact, the material will not hold the soil and erosion will occur underneath the

material.

Effectiveness

A geotextile's effectiveness depends upon the strength of the fabric and proper installation. For

example, when protecting a cut slope with a geotextile, it is important to properly anchor the

fabric using appropriate length and spacing of wire staples. This will ensure that it will not be

undermined by a storm event. 

Limitations

Geotextiles (primarily synthetic types) have the potential disadvantage of being sensitive to light

and must be protected prior to installation. Some geotextiles might promote increased runoff

and might blow away if not firmly anchored. Depending on the type of material used,

geotextiles might need to be disposed of in a landfill, making them less desirable than vegetative

stabilization. If the fabric is not properly selected, designed, or installed, the effectiveness may

be reduced drastically.

Maintenance

Regular inspections should be made to determine whether cracks, tears, or breaches have formed

in the fabric—it should be repaired or replaced immediately. It is necessary to maintain contact

between the ground and the geotextile at all times. 
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June 2002 5-35

Cost

Costs for geotextiles range from $0.50 to $10.00 per square yard depending on the type chosen

(SWRCP, 1991). Geosynthetic turf reinforcement mattings (TRMs) are widely used for

immediate erosion protection and long-term vegetative reinforcement, usually for steeply sloped

areas or areas exposed to runoff flows. The Erosion Control Technology Council (a geotextile

industry support association) estimates TRMs cost approximately $7.00 per square yard

(installed) for channel protection (ECTC, 2002a). Channel protection is one of the most

demanding of installations (much more demanding than general coverage of denuded area). The

ECTC estimates the cost to install a simple soil blanket (or rolled erosion control product), seed,

and fertilizer to be $1.00 per square yard (ECTC, 2002b).

5.1.5.1.2.6 VEGETATED BUFFER STRIPS

General Description

Vegetated buffers are areas of either natural or established vegetation that are maintained to

protect the water quality of neighboring areas. Buffer zones reduce the velocity of storm water

runoff, provide an area for the runoff to permeate the soil, allow groundwater recharge, and act

as filters to catch sediment. The reduction in velocity also helps to prevent soil erosion.

Applicability

Vegetated buffers can be used in any area that is able to support vegetation, but they are most

effective and beneficial on floodplains, near wetlands, along streambanks, and on steep, unstable

slopes. They are also effective in separating land use areas that are not compatible and in

protecting wetlands or waterbodies by displacing activities that might be potential sources of

nonpoint source pollution.

Design and Installation Criteria

To establish an effective vegetative buffer, the following guidelines should be followed:

• Soils should not be compacted.

• Slopes should be less than 5 percent.

• Buffer widths should be determined after careful consideration of slope, vegetation, soils,

depth to impermeable layers, runoff sediment characteristics, type and quantity of storm

water pollutants, and annual rainfall.

• Buffer widths should increase as slope increases.
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June 2002 5-36

• Zones of vegetation (native vegetation in particular), including grasses, deciduous and

evergreen shrubs, and understory and overstory trees, should be intermixed.

• In areas where flows are concentrated and velocities are high, buffer zones should be

combined with other structural or nonstructural BMPs as a pretreatment.

Vegetated strips have been studied extensively, with emphasis placed on their effectiveness in

removing sediment and other pollutants. Vegetated strips are most appropriate at sites where

sediment loads are relatively low, as high sediment loads will cause large quantities of

deposition along the leading edge of the vegetation. This deposition will cause the flow to divert

around the vegetation in a concentrated flow pattern, which will cause short-circuiting and

greatly reduce removal efficiency. Variability in vegetation density and uniformity often causes

similar problems. Removal efficiency depends on a combination of slope, length, and width of

the filter; density of the vegetation; sediment characteristics, hydraulics of the flow; and

infiltration. The interaction of these variables is complex and prevents the process from being

reduced to a simple relationship except on a local basis. For site-specific local conditions,

methods have been developed that allow trapping to be related to strip length and slope. 

Effectiveness

Considerable data have been collected on the effectiveness of buffer strips for specific

conditions. Numerous factors such as infiltration rate, flow depth, slope, dimensions of the

buffer, density and type of vegetation, sediment size, and sediment density impact removal rates.

Recent studies show that even short vegetative buffers can trap high percentages of sediment and

certain chemicals. A significant concern is whether flow is allowed to concentrate, which will

greatly reduce the travel time through the buffer and prevent the removal of pollutants. 

Several researchers have measured greater than 90 percent reductions in sediment and nitrate

concentrations; buffer/filter strips do a reasonably good job of removing phosphorus attached to

sediment, but are relatively ineffective in removing dissolved phosphorus (Gillman, 1994). 

However, since the hydraulics of flow through buffers strips are not well defined and can vary

considerably based on site conditions, it is difficult to consistently estimate the effectiveness of

buffers strips. 

Limitations

Vegetated buffers require plant growth before they can be effective, and land must be available

on which to plant the vegetation. If the cost of the land is very high, buffer zones might not be

cost-effective. Although vegetated buffers help to protect water quality, they usually do not

effectively counteract concentrated storm water flows to neighboring or downstream wetlands.
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June 2002 5-37

Maintenance

Keeping vegetation in vegetated buffers healthy requires routine maintenance, which (depending

on species, soil types, and climatic conditions) can include weed and pest control, mowing,

fertilizing, liming, irrigating, and pruning. Inspection and maintenance are most important when

buffer areas are first installed. Once established, vegetated buffers do not require much

maintenance beyond the routine procedures listed earlier and periodic inspections of the areas,

especially after any heavy rainfall and at least once a year. Inspections should focus on

encroachment, gully erosion, density of vegetation, evidence of concentrated flows through the

areas, and any damage from foot or vehicular traffic. If there is more than 6 inches of sediment

in one place, it should be removed. 

Cost

Conceptual cost estimates for grassed buffer strips can be made based on square footage using

unit cost values. R. S. Means (2000) estimates the cost of fine grading, soil treatment, and

grassing to be $2 per square yard of earth surface area. This cost estimate is based on

application of traditional lawn seed. The cost for field seed is lower than lawn seed, reducing the

coverage price. Where gently sloping areas just need to be grassed with acceptable species, the

cost can be as low as $0.38 per square yard.

5.1.5.1.2.7 EROSION CONTROL MATTING

General Description

Erosion control mats can be either organic or made from a synthetic material. A wide variety of

products exist to match the specific needs of the site. Organic mats are made from such materials

as wood fiber, jute net, and coconut coir fiber. Unlike organic matter, synthetic mats are

constructed from non-biodegradable materials and remain in place for many years. These

organic mats are classified as Turf Reinforcement Mats (TRMs) and Erosion Control and

Revegetation Mats (ECRMs) (USDOT, 1995).

Erosion control matting aids in plant growth by holding seeds, fertilizers, and topsoil in place. 

Matting can be used to stabilize the flow of channels or swales or to protect seedlings on recently

planted slopes until they become established. Matting can be used on tidal or streambanks

where moving water is likely to wash out new plantings. It can also be used to protect exposed

soils immediately and temporarily, such as when active piles of soil are left overnight. 

Applicability

Mulch mattings, netting, and filter fabrics are particularly useful in steep areas and drainage

swales where loose seed is vulnerable to being washed away or failing to survive dry soil

(UNEP, 1992). 
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June 2002 5-38

Erosion control mats can also be used to separate riprap and soil. This results in a

“sandwiching” effect, maintaining the riprap’s base and preventing the soil beneath from being

eroded.

Design and Installation Criteria

Matting is especially recommended for steep slopes and channels (UNEP, 1992).

Many types of erosion control mats are available. Therefore, the selected product should match

its purpose. Effective netting and matting require firm, continuous contact between the materials

and the soil. If there is no contact, the material will not hold the soil and erosion will occur

underneath the material.

Wood fiber or curled wood mat consists of curled wood with fibers, 80 percent of which are 150

mm or longer, with a consistent thickness and even distribution of fiber over the entire mat. The

top side of the mat is covered with a biodegradable plastic mesh. The mat is placed in the

channel or on the slope parallel to the direction of flow and secured with staples and check slots. 

This is applied immediately after seeding operations (USDOT, 1995). 

Jute net consists of jute yarn, approximately 5 mm in diameter, woven into a net with openings

that are approximately 10 by 20 mm (or 0.40 to 0.79 inches). The jute net is loosely laid in the

channel parallel to the direction of flow. The net is secured with staples and check slots at

intervals along the channel. Placement of the jute net is done immediately after seeding

operations (USDOT, 1995). 

Coconut blankets are constructed of biodegradable coconut fibers that resist decay for 5 to 10

years to provide long, temporary erosion control protection. The materials are often encased in

ultraviolet stabilized nets and sometimes have a composite, polypropylene structure to provide

permanent turf reinforcement. These materials are best used for waterway stabilization and

slopes that require longer periods to stabilize (USDOT, 1995). 

Under the synthetic mat category there are TRMs and ECRMs. Turf reinforcement mats are

three-dimensional polymer nettings or monofilaments formed into a mat. They have sufficient

thickness (>13 mm or 0.5 inch) and void space (>90 percent) to allow for soil filling and

retention. The mat acts as a traditional mat to protect the seed and increase germination. As the

turf establishes, the mat remains in place as part of the root structure. This gives the established

turf a higher strength and resistance to erosion (USDOT, 1995).

Erosion control and revegetation mats are composed of continuous monofilaments bound by

heat fusion or stitched between nettings. They are thinner than TRMs and do not have the void

space to allow for filling of soil. They act as a permanent mulch and allow vegetation to grow

through the mat (USDOT, 1995). 
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Effectiveness

The effectiveness of erosion control matting depends upon the strength of the material and

proper installation. For example, when protecting a cut slope with an erosion control mat, it is

important to anchor the mat properly. This will ensure that it will not be undermined by a storm

event. 

While erosion control blankets can be effective, their performance varies. Some general trends

are that organic materials tend to be the most effective (Harding, 1990) and that thicker materials

are typically superior (Fifield, 1992), but there are exceptions to both of these trends. 

Information about product testing of blankets is generally lacking. One notable exception is the

Texas Department of Transportation, which publishes the findings of their testing program in the

form of a list of acceptable and unacceptable materials for specific uses. 

Limitations

Erosion control mats (primarily synthetic types) are sensitive to light and for this reason must be

protected prior to installation. Some erosion control mats might cause an increase in runoff or

blow away if not firmly anchored. Erosion control mats might need to be properly disposed of in

a landfill, depending on the type of material. Effectiveness may be reduced if the fabric is not

properly selected, designed, or installed. 

Maintenance

Regular inspections are necessary to determine whether cracks, tears or breaches have formed in

the fabric. Contact between the ground and erosion control mat should be maintained at all

times and trapped sediment removed after each storm event. 

Cost

Costs for erosion control mats range from $0.50 to $10.00 per square yard depending on the type

chosen (SWRCP, 1991). Geosynthetic turf reinforcement mattings (TRMs) are widely used for

immediate erosion protection and long-term vegetative reinforcement, usually for steeply sloped

areas or areas exposed to runoff flows. The Erosion Control Technology Council (a geotextile

industry support association) estimates TRMs cost approximately $7.00 per square yard

(installed) for channel protection (ECTC, 2002a). Channel protection is one of the most

demanding of installations (much more demanding than general coverage of denuded area). The

ECTC estimates the cost to install a simple soil blanket (or rolled erosion control product), seed,

and fertilizer to be $1.00 per square yard (ECTC, 2002b).
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June 2002 5-40

5.1.5.1.2.8 TOPSOILING

General Description

Topsoiling is the placement of a surface layer of soil enriched in organic matter over a prepared

subsoil to provide a suitable soil medium for vegetative growth on areas with poor moisture, low

nutrient levels, undesirable pH, and/or the presence of other materials that would inhibit the

establishment of vegetation. Advantages of topsoil include its high organic-matter content and

friable consistency and its available water-holding capacity and nutrient content. The texture

and friability of topsoil are usually more conducive to seedling emergence root growth. In

addition to being a better growth medium, topsoil is often less erodible than subsoils, and the

coarser texture of topsoil increases infiltration capacity and reduces runoff. During construction,

topsoil is often removed from the project area and stockpiled. It is replaced over areas to be

grassed or landscaped during the final stages of the project. 

Applicability

Conditions where topsoiling apply include the following:

• Where a sufficient supply of quality topsoil is available.

• Where the subsoil or areas of existing surface soil present the following problems:

- The structure, pH, or nutrient balance of the available soil cannot be amended by

reasonable means to provide an adequate growth medium for the desired vegetation.

- The soil is too shallow to provide adequate rooting depth or will not supply necessary

moisture and nutrients for growth of desired vegetation.

- The soil contains substances toxic to the desired vegetation.

• Where high quality turf or ornamental plants are desired.

• Where slopes are 2:1 or flatter.

Design and Installation Criteria

The topsoil should be uniformly distributed over the subsoil to a minimum compacted depth of

50 mm (2 inches) on slopes steeper than 3 horizontal to 1 vertical and 100 mm (4 inches) on

flatter slopes. Thicknesses of 100 to 150 mm is preferred for vegetation establishment via

seeding. The topsoil should not be placed while in a frozen or muddy condition or when the

subsoil is excessively wet, frozen, or in a condition that is detrimental to proper grading or

seedbed preparation. The final surface should be prepared so that any irregularities are corrected

and depressions and water pockets do not form. If the topsoil has been treated with soil

sterilants, it should not be placed until the toxic substances have dissipated (USDOT, 1995). 

Table 5-8 summarizes the cubic yards of topsoil required for application to various depths.
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Table 5-8. Cubic Yards of Topsoil Required for Application to Various Depths

Depth (inches) Per 1,000 Sq Ft Per Acre

1 3.1 134

2 6.2 268

3 9.3 403

4 12.4 536

5 15.5 670

6 18.6 804

Source: Smolen et al., 1988.

On slopes and areas that will not be mowed, the surface may be left rough after spreading

topsoil. A disk may be used to promote bonding at the interface between the topsoil and subsoil

(Smolen et al., 1988). 

Effectiveness

No information is available describing the effectiveness of applying topsoil as a BMP.

Limitations

Limitations of applying topsoil can include to following:

• Topsoil spread when conditions were too wet, resulting in severe compaction.

• Topsoil mixed with too much unsuitable subsoil material, resulting in poor vegetation

establishment.

• Topsoil contaminated with soil sterilants or chemicals, resulting in poor or no vegetation

establishment.

• Topsoil not adequately incorporated or bonded with the subsoil, resulting in poor vegetation

establishment and soil slippage on sloping areas.

• Topsoiled areas not protected, resulting in excessive erosion.

Maintenance

Newly topsoiled areas should be inspected frequently until the vegetation is established. Eroded

or damaged areas should be repaired and revegetated. 
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Cost

Top soiling costs are a function of the price of topsoil, the hauling distance, and the method of

application. R. S. Means (2000) report unit cost values of $3 and $4 per square yard, for 4 and 6

inches of top soil cover, respectively. This price is for furnishing and placing of top soil, and

includes materials, labor, and equipment, with profit and overhead. 

5.1.5.2 WATER HANDLING PRACTICES

5.1.5.2.1 EARTH DIKE

General Description

An earth dike is a temporary or permanent ridge of soil designed to channel water to a desired

location. Dikes are used to divert the flow of runoff by constructing a ridge of soil that

intercepts and directs the runoff to the desired outlet or alternative management practice, such as

a pond. This practice serves to reduce the length of a slope for erosion control and protect

downslope areas. An earth dike can be used to prevent runoff from going over the top of a cut

and eroding the slope, directing runoff away from a construction site or building; to divert clean

water from a disturbed area; or to reduce a large drainage area into a more manageable size. 

Dikes should be stabilized with vegetation after construction (NAHB, n.d.). 

Applicability

Earth dikes are applicable to all areas; the size of the dike is correlated to the size of the drainage

area (NAHB, n.d.). 

Design and Installation Criteria

The location of dikes should take into consideration outlet conditions, existing land use,

topography, length of slope, soils, and development plans. The capacity of earth dikes and

diversions should be suitable for the area that is being protected, including adequate freeboard,

or extra depth that is added as a safety margin. For homes, schools, and industrial buildings, the

recommended design frequency storm is 50 years and the freeboard is 0.5 feet (NAHB, n.d.).

Earth dikes can be employed as a perimeter control. For small sites, a compacted 2-foot-tall dike

is usually suitable, if hydroseeded. Larger dikes will actually divert runoff to another portion of

the site, usually to a downstream sediment trap or basin. Therefore, the designer should ensure

that they have the capacity for the 10-year storm event, and that the channel created behind the

dike is properly stabilized to percent erosion (Brown et al., 1997). In addition, the downstream

structure must be sized to handle the flow from the dike. Dikes should be designed using

standard hydrologic and hydraulic calculations and certified by a professional hydrologist or

engineer. 
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Diversion dikes should be installed prior to the majority of the soil-disturbing activity. As soon

as the dike form is completed, it should be machine compacted, fertilized, and either seeded and

mulched or sodded. Excavated materials should be properly stockpiled for future use or

disposed of properly. Dikes should have an outlet that functions with a minimum of erosion. 

Depending on site conditions and outlet structures, the runoff directed by dikes may have to be

conveyed to a sediment-trapping device, such as a sediment basin or detention pond. As grades

increase over 4 percent, geotextile material or sod may be required to control erosion. Slopes

greater than 8 percent may require riprap. Dikes may be removed when stabilization of the

drainage area and outlet are complete (NAHB, n.d.). Dike design criteria must incorporate sitespecific conditions, as dimensions depend on expected flows, soil types, and climatic conditions. 

All of these inputs vary tremendously over different sections of the country. 

Effectiveness

No information has been found on the effectiveness of earth dikes used as BMPs, although

terraces often have sediment removal rates of up to 90 percent. 

Limitations

An erosion-resistant lining in the channel may be needed to prevent erosion in the channel

caused by excessive grade. In addition, the channel should be deepened and the grade realigned

if there is overtopping caused by sediment in the channel where the grade decreases or reverses. 

If overtopping occurs at low points in the ridge where the diversion crosses the shallow draw, the

ridge should be reconstructed with a positive grade toward the outlet at all points. Finally, if

there is erosion at the outlet, an outlet stabilization structure should be installed and if

sedimentation occurs at the diversion outlet, a temporary sediment trap should be installed.

Maintenance

An earth dike should be inspected for signs of erosion after every major rain event. Any repairs

and/or revegetation should be completed promptly (NAHB, n.d.). The following actions can be

taken to properly maintain an earth dike:

• Remove debris and sediment from the channel immediately after the storm event.

• Repair the dike to its original height.

• Check outlets and make necessary repairs to prevent gully formation.

• Clean out sediment traps when they are 50 percent full.
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• Once the work area has been stabilized, remove the diversion ridge, fill and compact the

channel to blend with the surrounding area, and remove sediment traps, disposing of unstable

sediment in a designated area.

Cost

The cost of an earth dike depends on the design and materials used. Small dikes can cost

approximately $2.00 per linear foot, while larger dikes can cost approximately $2.00 per cubic

yard. EPA states that an earth dike can cost approximately $4.50 per linear foot (NAHB, n.d.).

An alternative means to estimate conceptual costs for earthen dikes is to use unit cost values and

a rough estimate of the quantities needed. Shallow trenching (1 to 4 feet deep) with a backhoe in

areas not requiring dewatering can be performed for $4 to $5 per cubic yard of removed material

(R. S. Means, 2000). Based on this value, $2 per linear foot provides for 11 square feet of flow

area and $4.50 per linear foot provides for 24 square feet of flow area. This suggests that the

size of the dike is required prior to specifying a cost, which requires a site-specific hydrologic

evaluation. Based on standards for Virginia (1992), most small drainage areas (made up of 5

acre or less), diversion dikes are approximately 18" tall, with a 4.5' base. Assuming the

excavation volume equals the volume of the dike, the resulting excavation volume is

approximately 7 cubic feet per linear foot, which (conservatively) equates to $1.03 to $1.30 per

linear foot for construction costs. 

If the earthen dikes are to be permanent, then additional costs are incurred to vegetate the dike. 

R. S. Means (2000) estimates the cost of fine grading, soil treatment, and grassing is

approximately $2 per square yard of earth surface area. This adds approximately $6 per linear

foot of dike. Where gently sloping areas just need to be grassed with acceptable species, the cost

can be as low as $0.38 per square yard. 

5.1.5.2.2 TEMPORARY SWALE

General Description

The term swale (grassed channel, dry swale, wet swale, biofilter) refers to a series of vegetated,

open channel management practices designed specifically to treat and attenuate storm water

runoff for a specified water quality volume. As storm water runoff flows through these

channels, it is treated by filtering through the vegetation in the channel, filtering through a

subsoil matrix, and/or infiltration into the underlying soils. Variations of the grassed swale

include the grassed channel, dry swale, and wet swale. The specific design features and methods

of treatment differ in each of these designs, but all are improvements on the traditional drainage

ditch and incorporate modified geometry and other features for use of the swale as a treatment

and conveyance practice.
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Applicability

Grassed swales can be applied in most situations with some restrictions and are very well suited

for treating highway or residential road runoff because they are linear practices. Perimeter

dikes/swales should be limited to a drainage area of no more than 0.8 hectare and usually work

best on gently sloping terrain. Perimeter dikes may not work well on moderate slopes, and they

should never be established on slopes exceeding 20 percent (UNEP, 1994). 

Regional Applicability. Grassed swales can be applied in most regions of the country. In arid

and semi-arid climates, however, the value of these practices needs to be weighed against the

water needed to irrigate them.

Ultra-Urban Areas. Ultra-urban areas are densely developed urban areas in which little

pervious surface exists. Grassed swales are generally not well suited to ultra-urban areas because

they require a relatively large area of pervious surfaces.

Storm Water Hot Spots. Storm water hot spots are areas where land use or activities generate

highly contaminated runoff, with concentrations of pollutants in excess of those commonly

found in storm water. A typical example is a gas station or convenience store. With the

exception of the dry swale design, hot spot runoff should not be directed toward grassed

channels. These practices either infiltrate storm water or intersect the groundwater, making use

of the practices for hot spot runoff a threat to groundwater quality.

Storm Water Retrofit. A storm water retrofit is a storm water management practice (usually

structural), put into place after development has occurred, to improve water quality, protect

downstream channels, reduce flooding, or meet other specific objectives. One retrofit

opportunity using grassed swales modifies existing drainage ditches. Ditches have traditionally

been designed only to convey storm water away from roads as quickly as possible. In some

cases, it may be possible to incorporate features to enhance pollutant removal or infiltration such

as check dams (for example, small dams along the ditch that trap sediment, slow runoff, and

reduce the longitudinal slope). Since grassed swales cannot treat a large area, using this practice

to retrofit an entire watershed would be expensive because of the number of practices needed to

manage runoff from a significant amount of the watershed’s land area.

Cold Water (Trout) Streams. Grassed channels are a good treatment option within watersheds

that drain to cold water streams. These practices do not retain water for a long period of time

and often induce infiltration. As a result, standing water will not typically be subjected to

warming by the sun in these practices.
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Design and Installation Criteria

Temporary swales should be designed using standard hydrologic and hydraulic calculations. 

Designs should be certified by a professional hydrologist, engineer, or other appropriate

professional. 

Perimeter dikes/swales should be established before any major soil-disturbing activity takes

place. Dikes should be compacted with construction equipment to the design height plus 10

percent to allow for settlement. If they are to remain in place for longer than 10 days, they

should be stabilized using vegetation, filter fabric, or other material. Diverted water should be

directed to a sediment trap or other sediment treatment area (UNEP, 1994).

In addition to the broad applicability concerns described above, designers need to consider

conditions at the site level. In addition, they need to incorporate design features to improve the

longevity and performance of the practice, while minimizing the maintenance burden.

Siting Considerations

In addition to considering the restrictions and adaptations of grassed swales to different regions

and land uses, designers must ensure that this management practice is feasible at the site in

question. Depending on the design option, grassed channels can be highly restricted practices

based on site characteristics.

Drainage Area. Grassed swales generally should treat small drainage areas of less than 5 acres. 

If the practices are used to treat larger areas, the flows and volumes through the swale become

too large to design the practice to treat storm water runoff through infiltration and filtration.

Slope. Grassed swales should be used on sites with relatively flat slopes (less than 4 percent). 

Runoff velocities within the channel become too high on steeper slopes. This can cause erosion

and does not allow for infiltration or filtering in the swale.

Soils /Topography. Grassed swales can be used on most soils, with some restrictions on the

most impermeable soils. In the dry swale, a fabricated soil bed replaces on-site soils to ensure

that runoff is filtered as it travels through the soils of the swale.

Groundwater. The depth to groundwater depends on the type of swale used. In the dry swale

and grassed channel options, designers should separate the bottom of the swale from the

groundwater by at least 2 feet to prevent a moist swale bottom or contamination of the

groundwater. In the wet swale option, treatment is enhanced by a wet pool, which is maintained

by intersecting the groundwater.
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Design Considerations

Although the grass swale has different design variations, including the grassed channel, dry

swale, and wet swale, some design considerations are common to all three. One overriding

similarity is the cross-sectional geometry of all three options. Swales should generally have a

trapezoidal or parabolic cross-section with relatively flat side slopes (flatter than 3:1). Designing

the channel with flat side slopes maximizes the wetted perimeter. The wetted perimeter is the

length along the edge of the swale’s cross-section where runoff flowing through the swale is in

contact with the vegetated sides and bottom of the swale. Increasing the wetted perimeter slows

runoff velocities and provides more contact with vegetation to encourage filtering and

infiltration. Another advantage to flat side slopes is that runoff entering the grassed swale from

the side receives some pretreatment along the side slope. The flat bottom of all three should be

between 2 and 8 feet wide. The minimum width ensures an adequate filtering surface for water

quality treatment, and the maximum width prevents braiding, that is, the formation of small

channels within the swale bottom. 

Another similarity among all three designs is the type of pretreatment needed. In all three design

options, a small forebay should be used at the beginning of the front of the swale to trap

incoming sediments. A pea gravel diaphragm, a small trench filled with river run gravel, should

be used to pretreat runoff entering the sides of the swale.

Two other features designed to enhance the treatment ability of grassed swales are a flat

longitudinal slope (generally between 1 and 2 percent) and a dense vegetative cover in the

channel. The flat slope helps to reduce the velocity of flow in the channel. The dense vegetation

also helps reduce velocities, protect the channel from erosion, and act as a filter to treat storm

water runoff. During construction, it is important to stabilize the channel before the turf has

been established, either with a temporary grass cover or with the use of natural or synthetic

erosion control products.

In addition to treating runoff for water quality, grassed swales need to convey larger storms

safely. Typical designs allow the runoff from the 2-year storm (for example, the storm that

occurs, on average, once every 2 years) to flow through the swale without causing erosion. 

Swales should also have the capacity to pass larger storms (typically a 10-year storm) safely.

The length of the swale necessary to infiltrate runoff waters can be calculated by using a mass

balance of runoff waters and infiltration waters for a triangular-shaped cross-sectional area.

Design Variations

The following discussion identifies three different variations of open channel practices,

including the grassed channel, the dry swale, and the wet swale. 
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Grassed Channel. (Discussed in more length in sub-section 5.5.1.2.1) Of the three grassed

swale designs, grassed channels are the most similar to a conventional drainage ditch, with the

major differences being flatter side slopes and longitudinal slopes and a slower design velocity

for water quality treatment of small storm events. Of all of the grassed swale options, grassed

channels are the least expensive, but they also provide the least reliable pollutant removal. The

best application of a grassed channel is as pretreatment to other structural storm water practices.

One major difference between the grassed channel and most of the other structural practices is

the method used to size the practice. Most water quality practices for storm water management

are sized by volume. This method sets the volume available in the practice equal to the water

quality volume, or the volume of water to be treated in the practice. The grassed channel, on the

other hand, is a flow rate-based design. Based on the peak flow from the water quality storm

(this varies from region to region but a typical value is the 1-inch storm), the channel should be

designed so that runoff takes, on average, 10 minutes to flow from the top to the bottom of the

channel. A procedure for this design can be found in Design of Storm Water Filtering Systems

(CWP, 1996).

Dry Swales. Dry swales are similar in design to bioretention areas. These designs incorporate a

fabricated soil bed into their design. The existing soil is replaced with a sand/soil mix that meets

minimum permeability requirements. An underdrain system is used under the soil bed. This

system is a gravel layer that encases a perforated pipe. Storm water treated in the soil bed flows

through the bottom into the underdrain, which conveys this treated storm water to the storm

drain system. Dry swales are a relatively new design, but studies of swales with a native soil

similar to the man-made soil bed of dry swales suggest high pollutant removal.

Wet Swales. Wet swales intersect the groundwater and behave similarly to a linear wetland cell. 

This design variation incorporates a shallow permanent pool and wetland vegetation to provide

storm water treatment. This design also has potentially high pollutant removal. One

disadvantage of the wet swale is that its use in residential or commercial settings is unpopular

because the shallow standing water in the swale is often viewed as a potential nuisance by

homeowners.

Regional Variations

Cold Climates. In cold or snowy climates, swales may serve a dual purpose by acting as both a

snow storage/treatment and a storm water management practice. This dual purpose is

particularly relevant when swales are used to treat road runoff. If used for this purpose, swales

should incorporate salt-tolerant vegetation, such as creeping bentgrass.

Arid Climates. In arid or semi-arid climates, swales should be designed with drought-tolerant

vegetation, such as buffalo grass. As pointed out in the Applicability discussion, the value of

vegetated practices for water quality needs to be weighed against the cost of water needed to

maintain them in arid and semi-arid regions.
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Effectiveness

Swales act to control peak discharges in two ways. First, the grass reduces runoff velocity,

depending on the length and slope of the swale. Second, a portion of the storm water runoff

volume passes through the swale and infiltrates into the soil. Table 5-9 summarizes grassed

swale pollutant removal efficiencies.

Table 5-9. Grassed Swale Pollutant Removal Efficiency Data

Grassed Swale Removal Efficiencies

Study TSS TP TN NO3 Metals Bacteria Type

Goldberg, 1993 67.8 4.5 - 31.4 42–62 -100 Grassed channel

Seattle Metro and Washington

Department of Ecology, 1992 60 45 - -25 2–16 -25 Grassed channel

Seattle Metro and Washington

Department of Ecology, 1992 83 29 - -25 46–73 -25 Grassed channel

Wang et al., 1981 80 - - - 70–80 - Dry swale

Dorman et al., 1989 98 18 - 45 37–81 - Dry swale

Harper, 1988 87 83 84 80 88–90 - Dry swale

Kercher, Landon, and Massarelli, 

1983 99 99 99 99 99 - Dry swale

Harper, 1988 81 17 40 52 37–69 - Wet swale

Koon, 1995 67 39 - 9 -35 to 6 - Wet swale

Occoquan Watershed Monitoring

Lab, 1983 -100 -100 -100 - -100 - Drainage channel

Yousef et al., 1985 - 8 13 11 14–29 - Drainage channel

Occoquan Watershed Monitoring

Lab, 1983 -50 -9.1 -18.2 - -100 - Drainage channel

Yousef et al., 1985 - -19.5 8 2 41–90 - Drainage channel

Occoquan Watershed Monitoring

Lab, 1983 31 -23 36.5 - -100 to 33 - Drainage channel

Welborn and Veenhuis, 1987 0 -25 -25 -25 0 - Drainage channel

Yu, Barnes, and Gerde, 1993 68 60 - - 74 - Drainage channel

Dorman et al., 1989 65 41 - 11 14–55 - Drainage channel

Pitt and McLean, 1986 0 - 0 - 0 0 Drainage channel

Oakland, 1983 33 -25 - - 20–58 0 Drainage channel

Dorman et al., 1989 -85 12 - -100 14–88 - Drainage channel

Limitations

Common problems associated with swales include excessive erosion along unlined channels

(usually because of excessive grade), erosion or sedimentation at the outlet point, or overtopping

of the dike at low points (UNEP, 1994).

Additional limitations of the grass swale include the following:

• Grassed swales cannot treat a very large drainage area.

• Swales do not appear to be effective at reducing bacteria.
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• Wet swales may become a nuisance because of mosquito breeding.

• If designed improperly (for example, proper slope is not achieved), grassed channels will

have very little pollutant removal.

• A thick vegetative cover is needed for these practices to function properly.

Maintenance

As with any BMP, swales must be maintained to continue functioning as effective pollutant

removal methods. Maintenance may include occasional mowing, fertilizing, and liming. In

addition, any areas that become damaged by erosion should be immediately repaired and

replanted. The swales should be protected from concentrated flows and checked for downstream

obstructions. 

Cost

To produce a conceptual cost approximation, grassed channel construction costs can be

developed using unit cost values. Shallow trenching (1 to 4 feet deep) with a backhoe in areas

not requiring dewatering can be performed for $4 to $5 per cubic yard of removed material 

(R. S. Means, 2000). Assuming no disposal costs (i.e., excavated material is placed on either side

of the trench), only the cost of fine grading, soil treatment, and grassing (approximately $2 per

square yard of earth surface area) should be added to the trenching cost to approximate the total

construction cost. Site-specific hydrologic analysis of the construction site is necessary to

estimate the channel conveyance requirement and the desired retention time in the swale. It is

not unusual to have flows on the order of 2 to 4 cfs per acre served. 

For a design channel velocity of 1 foot per second, the resulting range in the channel crosssection area can be as low as 2 but as high as 4 square feet per acre drained. If the average

channel flow depth is 1 foot, then the low estimate for grassed channel installation is $0.74 per

square foot of channel bottom per acre served per foot of channel length. The high estimate is

$1.48 per square foot of channel bottom per acre served per foot of channel length.

Table 5-10 summarizes additional costs of grass swales.
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Table 5-10. Average Annual Operation and Maintenance Costs for a Grass Swale

Component

Estimated

Unit Cost ($)

$ for Swale Size:

0.5 m Deep

0.3 m Bottom Width

3 m Top Width 

$ for Swale Size:

1 m Deep

1 m Bottom Width

7 m Top Width Comments

Mowing 0.89/100 m2 145.0 241.0 Mow 2-3 times per year

General grass

care 8.8/100 m2 162.98 274.0

Grass maintenance area is (top

width + 3 m) x length

Debris/litter

removal 0.51/m2 93.0 93.0

Reseeding/

fertilization 0.35/m2 5.9 10.37

Area revegetated is 1% of

maintenance area per year

Inspection and

general

administration 0.74/m2 231.0 231.0 Inspection once per year

TOTAL 638.0 850.0

Source: Ellis, 1998.

5.1.5.2.3 TEMPORARY STORM DRAIN DIVERSION

General Description

A temporary storm drain diversion is a pipe that reroutes an existing drainage system to

discharge flow into a sediment trap or basin. This practice reduces the amount of sedimentladen runoff from construction sites that enters waterbodies without treatment. Temporary storm

drain diversions can be used when a permanent storm water drainage system has not yet been

installed. It should be recognized that diversion channels can also be installed but are not

considered in the following discussion. 

Applicability

A temporary storm drain diversion should be used to temporarily redirect discharge to a

permanent outfall and should remain in place until the area draining to the storm sewer is no

longer disturbed. Temporary storm drain diversions can also be combined with other structures

and used as a sediment-trapping device when the completion of a permanent outfall has been

delayed; alternatively, a sediment trap can be placed below a permanent outfall to remove

sediment before the final flow discharge.

Design and Installation Criteria

Since the diversion is only temporary, the layout of piping and the overall impact of the

diversion’s installation on post-construction drainage patterns must be considered. Once

construction is completed, the temporary diversion should be moved to restore the original

system. The following activities should be done at this time:
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• The storm drain should be flushed before the sediment trap is removed.

• The outfall should be stabilized.

• Graded areas should be restored.

• State or local specifications should be checked for more detailed requirements and an

appropriate professional should certify that the design meets local hydrologic and hydraulic

requirements.

Effectiveness

If installed properly to capture the bulk of runoff from a construction site, temporary storm drain

diversions can be effective in reducing the discharge of sediment-laden, untreated water to

waterbodies. When used in combination with other erosion and sediment control practices such

as minimized clearing or vegetative and chemical stabilization, the level of pollution from a

construction site can be substantially reduced or eliminated. 

Limitations

Installation of a temporary storm drain diversion may result in the disturbance of existing storm

drainage patterns. Care must be taken to ensure that the original system is properly restored

once the temporary system is removed. The most common source of problems is excessive

velocity at the outlet. Installation of an outlet stabilization structure is typically required and

may be constructed of riprap, reinforced concrete, geotextile linings, or a combination. 

Maintenance

Once installed, temporary storm drain diversions require very little maintenance. Frequent

inspection and maintenance of temporary storm drain systems, especially after large storms, 

should ensure that pipe clogging does not occur and that runoff from the site is being

successfully diverted. After removal of the temporary diversion, the permanent storm drain

system should be carefully inspected to ensure that drainage patterns have not been altered by

the temporary system.

Cost

Depending on the size of the construction site, a temporary storm drain diversion can be costly. 

Costs include those associated with materials needed to construct the diversion and sediment trap

or basin (mainly piping, concrete, and gravel), and also labor costs for installation and removal

of the system, all of which may involve excavation, regrading, and inspections. Based on the

variety of conditions that can affect storm drain diversion designs, typical costs per installation

are not presented here. However, site-specific cost estimates can be produced using unit cost
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values along with site-specific quantity estimates. R. S. Means (2000) indicates a range of pipe

costs for surface placement, between $5.00 per linear foot for 4" diameter PVC piping, and $9.20

per linear foot for 10" diameter PVC piping. On construction sites, temporary inlets and outlets

are usually formed by small rock-lined depressions. Assuming 4 cubic yards of crushed rock

(1.5" mean diameter) per opening, an inlet and outlet combine to add approximately $200 per

pipe installation, based on $25 per cubic yard of stone (R. S. Means, 2000).

5.1.5.2.4 PIPE SLOPE DRAIN

General Description

Pipe slope drains are used to reduce the risk of erosion on slopes by discharging runoff to

stabilized areas. Consisting of a metal or plastic flexible pipe if temporary, or pipes or paved

chutes if permanent, these drains are placed from the top to the bottom of a slope to carry surface

runoff from the top to the bottom of a slope that has already been damaged by erosion or is at

high risk for erosion. These drains are also used to drain saturated slopes that have the potential

for soil slides. 

Applicability

Temporary slope drains can be used on most disturbed slopes to eliminate gully erosion

problems resulting from concentrated flows discharged at a diversion outlet. Slope drains should

be used as a temporary measure for as long as the drainage area remains disturbed. They will

need to be moved once construction is complete and a permanent storm drainage system is

established. Appropriate restoration measures will then need to be taken, such as adjusting

grades and flushing sediment from the pipe before it is removed (UNEP, 1994).

Design and Installation Criteria

Pipe slope drains can be placed directly on the ground or buried under the surface. The inlet

should be located at the top of the slope and should be fitted with an apron, attached with a water

tight connection. Filter cloth should be placed under the inlet to prevent erosion. Flexible pipes,

which are positioned on top of the ground, should be securely anchored with grommets placed

10 feet on center. The outlet at the bottom of the slope should also be stabilized with riprap. 

The riprap should be placed along the bottom of a swale that leads to a sediment-trapping

structure or another stabilized structure. 

Slope drain pipe sizes are based on drainage area and the size of the design storm. Pipes should

be connected to a diversion ridge at the top of the slope by covering with compacted fill material

where it passes through the ridge. Discharge from a slope drain should be to a sediment trap,

sediment basin, or other stabilized outlet (UNEP, 1994).
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Pipe slope drains should be installed perpendicular to the contour down the slope, and the design

should be able to handle the peak runoff for the 10-year storm. Recommendations of slope drain

diameter are summarized in Table 5-11 (NAHB, n.d).

Table 5-11. Recommended Pipe/Tubing Sizes for Slope Drains

Maximum Drainage

Area (acres)

Pipe/Tubing

Diametera(inches)

Pipe/Tubing

Diameterb (inches)

Pipe/Tubing

Diameterc (inches)

0-0.5

 0.5 12 12 8

 0.75 10

1.0 12

1.5 18 18 Individually designed

2.5 21

3.5 24 24

5.0 30 a

 UNEP, 1994.

b

 USDOT, 1995.

c

 IDNR, 1992.

Recently graded slopes that do not have permanent drainage measures installed should have a

temporary slope drain and a temporary diversion installed. A temporary slope drain used in

conjunction with a diversion conveys storm water flows and reduces erosion until permanent

drainage structures are installed.

The following are design recommendations for temporary slope drains:

• The drain should consist of heavy-duty material manufactured for the purpose and have

grommets for anchoring at a spacing of 10 feet or less.

• Minimum slope drain diameters should be observed for varying drainage areas.

• The entrance to the pipe should consist of a standard flare end section of corrugated metal. 

The corrugated metal pipe should have watertight joints at the ends. The rest of the pipe is

typically corrugated plastic or flexible tubing, although for flatter, shorter slopes, a

polyethylene-lined channel is sometimes used.

• The height of the diversion at the pipe should be the diameter of the pipe plus 0.5 foot.

• The outlet should be located at a reinforced or erosion-resistant location.
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• Temporary slope drains should be designed to adequately convey runoff for a desired

frequency storm, typically either 2 years or 10 years depending on local regulations. Both

the size and the spacing can be determined based on the contributing drainage area. Drains

are spaced at intervals corresponding to the specified drainage areas. For larger drainage

areas and critical locations, the drains should be sized on an individual basis (USDOT,

1995). 

• Slope drains should be constructed in conjunction with diversion berms such that the berms

are not overtopped. At the pipe inlet, the top of the berm should be a minimum of 300

millimeters (11.81 inches) higher than the top of the pipe. The entrance should be

constructed of a standard flared end section or a Tee section if designed properly. The

entrance should be placed in a 150 millimeters (5.90 inches) minimum depressed sump

(USDOT, 1995).

• The outlet of the slope drain must be protected with a riprap apron. If the slope drain is

draining a disturbed area and sufficient right-of-way is available, the drain may empty into a

sediment trap (USDOT, 1995). Table 5-12 summarizes slope drain characteristics.

Table 5-12. Slope Drain Characteristics

Capacity 2-yr frequency, 24-hr-duration storm event

Material Strong, flexible pipe, such as heavy duty, nonperforated, corrugated plastic

Inlet section Standard “T” or “L” flared-end section with metal toe plate

Connection to ridge at top of

slope

Compacted fill over pipe with minimum dimensions, 1.5 ft depth, 4 ft top width, and 6

in higher than ridge

Outlet

Pipe extends beyond toe of slope and discharges into a sediment trap or basin unless

contributing drainage area is stable

Source: IDNR, 1992.

Effectiveness

There is currently no information on the effectiveness of pipe slope drains. 

Limitations

The area drained by a temporary slope drain should not exceed 5 acres. Physical obstructions

substantially reduce the effectiveness of the drain. A common slope drain problem is

overtopping of the inlet due to an undersized or blocked pipe, or erosion at the outlet point due to

insufficient protection (UNEP, 1994). Other concerns are failures from overtopping because of

inadequate pipe inlet capacity and reduced diversion channel capacity and ridge height.
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Solutions to common problems include the following (IDNR, 1992):

• Washout - A washout along a pipe due to seepage and piping may be caused by inadequate

compaction, insufficient fill, or installation that may be too close to the edge of the slope.

• Overtopping caused by undersized or blocked pipe - The drainage area may be too large.

• Overtopping caused by improper grade of channel and ridge - A positive grade should be

maintained.

• Overtopping caused by poor entrance conditions and trash buildup at the pipe inlet - Deepen

and widen the channel at the pipe entrance and frequently inspect and clear the inlet.

• Erosion at outlet - The pipe should be extended to a stable grade or an outlet stabilization

structure is needed.

• Displacement or separation of pipe - The pipe should be tied down and the joints secured.

Maintenance

Pipe slope drains must be inspected after each significant runoff event for evidence of erosion

and uncontrolled runoff. Any repairs to the drain should be made immediately. Significant

amounts of sediment trapped at the outfall should also be removed in a timely manner and

disposed of properly (NAHB, n.d.).

The following actions should be taken to properly maintain a pipe slope drain (IDNR, 1992):

• Inspect slope drains and supporting diversions once a week and after every storm event.

• Check the inlet for sediment or trash accumulation; clear and restore to proper entrance

condition.

• Check the fill over the pipe for settlement, cracking, or piping holes; repair immediately.

• Check for holes where the pipe emerges from the dike; repair immediately.

• Check the conduit for evidence of leaks or inadequate anchoring; repair immediately.

• Check the outlet for erosion or sedimentation; clean and repair, or extend if necessary.

• Once slopes have been stabilized, remove the temporary diversions and slope drains, and

stabilize all disturbed areas. 
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Cost

The cost of pipe slope drains and their installation varies with the design and materials used. 

Site-specific cost estimates can be produced using unit cost values with site-specific quantity

estimates. R. S. Means (2000) indicates a range of pipe costs for surface placement between

$5.00 per linear foot for 4" diameter PVC piping, and $9.20 per linear foot for 10" diameter PVC

piping. On construction sites, temporary inlets and outlets are usually formed by small rock-lined

depressions. Assuming 4 cubic yards of crushed rock (1.5" mean diameter) per opening, an inlet

and outlet combine to add approximately $200 per pipe installation, based on $25 per cubic yard

of stone (R. S. Means, 2000).

5.1.5.2.5 STONE CHECK DAM

General Description

A check dam is a small temporary barrier or dam constructed across a drainage channel or swale

to reduce the velocity of the flow. By reducing the flow velocity, the erosion potential is

reduced, detention times are lengthened, and more sediments are able to drop out of the water

column. Check dams can be constructed of stone, gabions, treated lumber, or logs 

(NAHB, n.d.).

Check dams are inexpensive and easy to install. They may be used permanently if designed

properly to allow a high proportion of sediment in the runoff to settle out and reduce velocity

and may provide aeration of the water (NAHB, n.d.). However, the use of check dams in a

channel should not be a substitute for the use of other sediment-trapping and erosion control

measures. As with most other temporary structures, check dams are most effective when used in

combination with other storm water and erosion and sediment control measures.

Applicability

Check dams are commonly used (1) in channels that are degrading but where permanent

stabilization is impractical because of their short period of usefulness and (2) in eroding channels

where construction delays or weather conditions prevent timely installation of erosion-resistant

linings (IDNR, 1992).

Check dams are also useful in steeply sloped swales, in small channels, in swales where

adequate vegetative protection cannot be established, or in swales or channels that will be used

for a short period of time where it is not practical to line the channel or implement other flow

control practices (USEPA, 1993). In addition, check dams are appropriate where temporary

seeding has been recently implemented but has not had time to fully develop and take root. The

contributing drainage area should range from 2 to 10 acres. Check dams should be used only in

small open channels that will not be overtopped by flow once the dams are built and should not

be built in stream channels, either intermittent or perennial (UNEP, 1994). 
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Design and Installation Criteria

Check dams can be constructed from a number of different materials. Most commonly, they are

made of rock, logs, sandbags, or straw bales. Rock or stone is often preferred because of its

cost-effectiveness and longevity. Logs and straw bales will decay with time and are not

recommended as they may cause waterway blockage if they fail. When using rock or stone, the

material diameter should be 2 to 15 inches. The stones should be extended 18 inches beyond the

banks, and the side slopes should be 2:1 or flatter. Lining the upstream side of the dam with a

foot of 1- to 2-inch gravel may improve the efficiency of the dam (NAHB, n.d.). Logs should

have a diameter of 6 to 8 inches. Regardless of the material used, careful construction of a check

dam is necessary to ensure its effectiveness.

The distance between rock check dams will vary depending on the slope of the ditch, with closer

spacing when the slope is steeper. The size of stone used in the check dam should also vary with

the expected design velocity and discharge. As velocity and discharge increase, the rock size

should also increase. For most rock check dams, 3 inches to 12 inches is a suitable stone size. 

To improve the sediment-trapping efficiency of check dams, a filter stone can be applied to the

upstream face. A well-graded coarse aggregate that is less than 1 inch in size can be used as a

filter stone.

All check dams should have a maximum height of 3 feet. The center of the dam should be at

least 6 inches lower than the edges. This design creates a weir effect that helps to channel flows

away from the banks and prevent further erosion. Additional stability can be achieved by

implanting the dam material approximately 6 inches into the sides and bottom of the channel

(VDCR, 1995).

When installing more than one check dam in a channel, outlet stabilization measures should be

installed below the final dam in the series. Because this area is likely to be vulnerable to further

erosion, riprap or some other stabilization measure is highly recommended. 

Effectiveness

Field experience has shown that rock check dams are more effective than silt fences or straw

bales to stabilize wet-weather ditches (VDCR, 1995). Straw bales have been shown to have very

low trapping efficiencies and should not be used for check dams. For long channels, check dams

are most effective when used in a series, creating multiple barriers to sediment-laden runoff.
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Limitations

Check dams should not be used in perennial streams unless approved by an appropriate

regulatory agency (USEPA, 1992; VDCR, 1995). Because the primary function of check dams

is to slow runoff in a channel, they should not be used as a stand-alone substitute for other

sediment-trapping devices. Also, leaves have been shown to be a significant problem as they 

clog check dams; therefore, increased inspection and maintenance might be necessary in the fall. 

Common problems with check dams include channel bypass and severe erosion when

overtopped and ineffectiveness due to accumulated sediment and debris. When designing check

dams, the fact that they will reduce the capacity of a channel to transmit storm water runoff and

thus will need to be sized appropriately should be taken into account (UNEP, 1994). The check

dam may also kill grass linings in the channel if the water level remains high after it rains or if

there is significant sedimentation. In addition, a check dam may reduce the hydraulic capacity of

the channel and create turbulence, which erodes the channel banks (NAHB, n.d.).

Maintenance

Check dams should be inspected periodically to ensure that they have not been repositioned as a

result of storm water flow. In addition, the center of a check dam should always be lower than

its edges. Additional stone may have to be added to maintain the correct height. Sediment

should not be allowed to accumulate to more than half the original dam height. Any required

maintenance should be performed immediately. When check dams are removed, care must be

taken to remove all dam materials to ensure proper flow within the channel. The channel should

subsequently be seeded for stabilization (NAHB, n.d.).

Cost

The cost of check dams varies based on the material used for construction and the width of the

channel to be dammed. In general, it is estimated that check dams constructed of rock cost about

$100 per dam (USEPA, 1992). Brown (1997) estimated rock check dam would cost

approximately $62 per installation, including the cost for filter fabric bedding. Other materials,

such as logs and sandbags, may be a less expensive alternative, but they might require higher

maintenance costs.

5.1.5.2.6 LINED WATERWAYS

General Description

Lined channels convey storm water runoff through a stable conduit. Vegetation lining the

channel reduces the flow velocity of concentrated runoff. Lined channels usually are not

designed to control peak runoff loads by themselves and are often used in combination with

other BMPs such as subsurface drains and riprap stabilization. Where moderately steep slopes
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require drainage, lined channels can include excavated depressions or check dams to enhance

runoff storage, decrease flow rates, and enhance pollutant removal. Peak discharges can be

reduced through temporary detention in the channel. Pollutants can be removed from storm

water by filtration through vegetation, by deposition, or in some cases by infiltration of soluble

nutrients into the soil. The degree of pollutant removal in a channel depends on the residence

time of the water in the channel and the amount of contact with vegetation and the soil surface,

but pollutant removal is not generally the major design criterion. 

Often construction increases the velocity and volume of runoff, which causes erosion in newly

constructed or existing urban runoff conveyance channels. If the runoff during or after

construction will cause erosion in a channel, the channel should be lined or flow control

practices instituted. The first choice of lining should be grass or sod since this reduces runoff

velocities and provides water quality benefits through filtration and infiltration. If the velocity in

the channel would erode the grass or sod, riprap, concrete, or gabions can be used (USEPA,

2000). Geotextile materials can be used in conjunction with either grass or riprap linings to

provide additional protection at the soil-lining interface. 

Applicability

Lined channels typically are used in residential developments, along highway medians, or as an

alternative to curb and gutter systems. Grass-lined channels should be used to convey runoff

only where slopes are 5 percent or less. These channels require periodic mowing, occasional

spot-seeding, and weed control to ensure adequate grass cover (UNEP, 1994). 

Lined channels should be used in areas where erosion-resistant conveyances are needed, such as

in areas with highly erodible soils and slopes of less than 5 percent. They should be installed

only where space is available for a relatively large cross-section. Grassed channels have a

limited ability to control runoff from large storms and should be used with the recommended

allowable velocities for the specific soil types and vegetative cover.

Design and Installation Criteria

The design of a lined waterway requires proper determination of the channel dimensions. It must

ensure that (1) the velocity of the flowing water will not wash out the waterway and that (2) the

capacity of the waterway is sufficient to carry the surface flow from the watershed without

overtopping.

Vegetative-Lined Channels. Grass-lined channels have been previously discussed in detail and

are only summarized in this section. The allowable velocity of water in the waterway depends

upon the type, condition, and density of the vegetation, as well as the erosive characteristics of

the soil. Uniformity of vegetative cover is important because the stability of the most sparsely

covered area determines the stability of the channel. Grasses are a better vegetative cover than

legumes because grasses resist water velocity more effectively.
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Vegetative-lined channels may have triangular, parabolic, or trapezoidal cross-sections. Side

slopes should not exceed 3:1 to facilitate the establishment, maintenance, and mowing of

vegetation. A dense cover of hardy, erosion-resistant grass should be established as soon as

possible following grading. This may necessitate the use of straw mulch and the installation of

protective netting until the grass becomes established. If the intent is to create opportunities for

runoff to infiltrate into the soil, the channel gradient should be kept near zero, the channel

bottom must be well above the seasonal water table, and the underlying soils should be relatively

permeable (generally, with an infiltration rate greater than 2 centimeters [0.78 inches] per hour). 

Rock-Lined Channels. Riprap-lined channels may be installed on somewhat steeper slopes

than grass-lined channels. They require a foundation of filter fabric or gravel under the riprap.

Generally, side slopes should not exceed 2:1, and riprap thickness should be 1.5 times the

maximum stone diameter. Riprap should form a dense, uniform, well-graded mass 

(UNEP, 1994).

Lined channels should be sited in accordance with the natural drainage system and should not

cross ridges. The channel design should not have sharp curves or significant changes in slope. 

Channels should not receive direct sedimentation from disturbed areas and should be established

only on the perimeter of a construction site to convey relatively clean storm water runoff and

separated from disturbed areas by a vegetated buffer or other BMP to reduce sediment loads. 

Basic design recommendations for lined channels include the following:

• Construction and vegetation of the channel should occur before grading and paving activities

begin.

• Design velocities should be below 5 feet per second.

• Geotextiles can be used to stabilize vegetation until it is fully established.

• Covering the bare soil with sod or geotextiles can provide reinforced storm water

conveyance immediately.

• Triangular-shaped channels should be used with low velocities and small quantities of

runoff; parabolic grass channels are used for larger flows and where space is available;

trapezoidal channels are used with large flows of low velocity (low slope).

• Outlet stabilization structures might be needed if the runoff volume or velocity has the

potential to exceed the capacity of the receiving area.

• Channels should be designed to convey runoff from a 10-year storm without erosion.
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• The sides of the channel should be sloped less than 3:1, with V-shaped channels along roads

sloped 6:1 or less for safety.

• All trees, bushes, stumps, and other debris should be removed during construction. 

Effectiveness

Lined channels can effectively transport storm water from construction areas if they are designed

for expected flow volumes and velocities and if they do not receive sediment directly from

disturbed areas. 

Limitations

Lined channels, if improperly installed, can alter the natural flow of surface water and have

adverse impacts on downstream waters. Additionally, if the design capacity is exceeded by a

large storm event, the vegetation might not be sufficient to prevent erosion and the channel

might be destroyed. Clogging with sediment and debris reduces the effectiveness of grass-lined

channels for storm water conveyance. 

Common problems in lined channels include erosion of the channel before vegetation is fully

established and gullying or head cutting in the channel if the grade is too steep. In addition, trees

and brush tend to invade lined channels, causing maintenance problems.

Riprap-lined channels can be designed to safely convey greater runoff volumes on steeper

slopes. However, they should generally be avoided on slopes exceeding 10 percent because stone

displacement, erosion of the foundation, or channel overflow and erosion resulting from a

channel that is too small can occur. Thus, channels established on slopes greater than 10 percent

will usually require protection with rock gabions, concrete, or other highly stable and protective

surfaces (UNEP, 1994).

Maintenance

Maintenance requirements for lined channels are relatively minimal. During the vegetation

establishment period, the channels should be inspected after every rainfall. Other maintenance

activities that should be carried out after vegetation is established are mowing, litter removal,

and spot vegetation repair. The most important objective in the maintenance of lined channels is

maintaining a dense and vigorous growth of turf. Periodic cleaning of vegetation and soil

buildup in curb cuts is required so that water flow into the channel is unobstructed. During the

growing season, channel grass should be cut no shorter than the level of design flow, and the

cuttings should be removed promptly. 
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Cost

Costs of grassed channels range according to depth, with a 1.5-foot-deep, 10-foot-wide grassed

channel estimated at $6,395 to $17,075 per trench, while a 3.0-foot-deep, 21-foot-wide grassed

channel is estimated at $12,909 to $33,404 per trench (SWRPC, 1991).

Readers are also referred to the discussion of costs for grass-lined channels, which contains

many of the design and cost elements required for installing lined waterways. Designers have a

range of options for lining new channels. Geosynthetic turf reinforcement mattings (TRMs) can

be used for immediate erosion protection in channels exposed to runoff flows. The Erosion

Control Technology Council (a geotextile industry support association) suggests TRMs cost

approximately $7.00 per square yard (installed) for channel protection (ECTC, 2002a). R. S.

Means indicates machine-placed riprap costs of approximately $40 per cubic yard. The riprap

maximum size is typically between 6 and 12 inches, depending on the channel design velocity. A

cubic yard of riprap will cover between 36 and 18 square feet of channel bed for these riprap

sizes (assuming depth of riprap is 1.5 times the maximum size). These estimates suggests that

riprap lining will be between $10 and $20 per square foot of channel (Costs include materials,

labor, and equipment, with overhead and profit).

5.1.5.3 SEDIMENT TRAPPING DEVICES

The devices listed under this group of BMPs trap sediment primarily through impounding water

and allowing for settling to occur (Haan et al., 1994). Silt fence, super silt fence, straw bale

dikes, sediment traps, and sediment basins all control flow through a porous flow control system

such as filter fabric or straw bales or they use a dam to impound water with a pipe, open channel,

or rock fill outlet. The filtering capacity of silt fence (filter fabric) contributes only a small

amount of trapping, but serves to make the fence less porous and hence increases ponding . For

steady-state flows, the trapping that occurs behind the flow control device can be shown to be

directly proportional to the surface area and indirectly proportional to flow through the system

(Haan et al., 1994). The ratio of the surface area to flow is known as the overflow rate, and

trapping in such systems is predicted by the ratio of overflow rate to particle settling velocity. 

Although flows in nature are inherently non-steady state and more complex than steady-state

systems, studies have shown that the best predictor of trapping in such systems is still the ratio of

settling velocity to overflow rate (Hayes et al., 1984). In the case of non-steady state, the

overflow rate is best defined by the ratio of peak discharge from the system to a surface area

(Hayes et al., 1984; McBurnie et al., 1990). 

The amount of trapping in these structures depends on the size of the structure, flow rates into

the system, hydraulics of the flow control system, the size distribution of the sediment flowing

into the structure, and the chemistry of the sediment-water system (Haan et al., 1994). Trapping

can be enhanced by chemical treatment of flows into the structure, but the impacts have not been

widely defined for varying mineralogy and chemistry of the sediment-water system (Haan et al.,

1994; Tapp and Barfield, 1986). Recent studies have been conducted on the application of
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polyacrilamides (PACs) to disturbed areas for enhancing settling (Benik et al., 1998; Masters et

al., 2000; Roa-Espinosa et al., 2000), but results have not been definitive. No known studies

have evaluated the impacts of PAC application to disturbed areas on settling in sediment

trapping devices.

Sediment flowing into sediment trapping devices is composed of primary particles and

aggregated particles. Aggregates are formed when clays, silts, and sands are cemented together

to form larger particles that have settling velocities far greater than those of any individual

particles alone although the degree of aggregation depends on the amount of cementing material

present (typically clays and organic matter). Since the aggregates have higher settling velocities

than primary particles, the degree of aggregation that is present has a large impact on the

trapping that occurs. Procedures are available to measure the combined size distribution of

aggregate and primary particle size distribution (Barfield et al., 1979; Haan et al., 1994). 

Procedures are also available to predict particle size distributions of aggregates and primary

particles (Foster et al., 1985) but have not been found to be very accurate for subsoils exposed

during construction in at least one study (Barfield et al., 1983). 

In the absence of chemical treatment, the sediment that can be captured in sediment trapping

devices is typically the settleable solids. To trap the smaller size clay particles, structures with

surface areas larger than the construction site itself would have to built in many cases (Barfield,

2000). Chemical treatment can be used to reduce the size, but it has not been adopted on a wide

scale because of the cost and complexity of the operation (Tapp et al., 1981).

Sediment trapping devices also provide some storm water detention by virtue of detaining flows

long enough to allow sediment to settle out and be deposited. However, to operate as a storm

water detention structure, the design should include storm water detention as well.

Virtually all of the available information on sediment trapping structures, both theoretical and

experimental, is on impacts to receiving waters and not downstream effects. In a very limited

analysis, Barfield (2000) combined the SEDIMOT II computer model together with the

FLUVIAL model to theoretically evaluate the impact of sediment trapping structures on

downstream geomorphology in a Puerto Rican watershed.

5.1.5.3.1 SILT FENCE

General Description

Silt fences are used as temporary sediment barriers consisting of filter fabric anchored across and

supported by posts. Their purpose is to retain sediment from small disturbed areas by reducing

the velocity of sediment-laden runoff and promoting sediment deposition (Smolen et al., 1998). 

Silt fences capture sediment by ponding water and allowing for deposition, not by filtration. Silt

fence fabric first screens silt and sand from runoff, resulting in clogging of the lower part of the
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fence. The pooling water allows sediments to settle out of the runoff. Silt fences work best in

conjunction with temporary basins, traps, or diversions.

Applicability 

Silt fences are generally placed at the toe of fills, along the edge of waterways, and along the site

perimeter. The fences should not be used in drainage areas with concentrated and high flows, in

large areas, or in ditches and swales where concentrated flow is present. 

The drainage area for the fence should be selected based on design storms and local hydrologic

conditions so that the silt fence is not expected to overtop. A typical design calls for no greater

than 1⁄4 acre per 100 feet of fence, but this is highly variable depending on climate. The fence

should be stable enough to withstand runoff from a 10-year peak storm. Table 5-13 lists the

maximum slope length specified by the USDOT. These slope lengths should be based on

sediment load and flow rates. This would mean that the values given below should be adjusted

for climatic conditions instead of “one size fits all” for a silt fence to ensure maximum

effectiveness.

Table 5-13. Maximum Slope Lengths for Silt Fences 

Slope (%) 18- inch (460 mm) Fence 30- inch (760 mm) Fence

2 250 ft (75 m) 500 ft (150 m)

 5 100 ft (30m) 250 ft (75 m)

10 50 ft (15 m) 150 ft (45 m)

20 25 ft (8 m) 70 ft (21 m)

25 6 m (20 ft) 55 ft (17 m)

30 15 ft (5 m) 45 ft (14 m)

35 15 ft (5 m) 40 ft (12 m)

40 15 ft (5 m) 35 ft (10 m)

45 10 ft (3 m) 30 ft (9 m)

50 10 ft (3m) 25 ft (8m)

Source: USDOT, 1995.

Typical standards and specifications call for the silt fence to be located on fairly level ground

and follow the land contour. However, field evaluations by Barfield and Hayes (1992, 1999) in

South Carolina and Kentucky indicate that installations on the contour as well as along a slope

have problems with undercutting. In either case, the installations are such that a slight slope may

occur along the fence in spite of the best installation practices. Runoff can move down the

contour until a weak spot occurs in the buried toe and undercuts the fence. Alternatively, flow

may move to a low spot where it accumulates and causes an overtopping. In either case,

trapping by the silt fence is essentially zero, and flows have then been concentrated at a point

causing downslope channel erosion. 
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1

d15:15 percent by weight of suspended solids are smaller than those that are trapped by this device; 

Similarly d50 indicates that 50 percent by weight of suspended solids are smaller than those trapped.

June 2002 5-66

Design and Installation Criteria 

Design criteria are of two types:

Hydrologic design for a required trapping of sediment and flow rate to pass the design storm.

Selection of appropriate installation criteria such that the silt fence will perform as designed. 

Hydrologic Design

Hydrologic design should result in a design that passes the design storm without causing damage

while trapping the required amount of sediment. It is necessary to use either a database or some

type of model to develop the appropriate hydrologic design. Efforts to model the sediment

trapping that occurs through the use of a silt fence have resulted in models that predict the

settling in the ponded area upstream from the fence (Barfield et al., 1996; Lindley et al., 1998). 

The results from model simulations show that trapping depends primarily on the surface area of

the impounded water and the flow rate through the filter. The models utilize a clear water slurry

flow rate, typically specified by the manufacturer, to predict discharge. However, numerous

studies have shown that sediment laden flows cause clogging of the geotextiles used to construct

the fence, dependent on the opening size and size of the sediment (Britton et al., 2001; Wyant,

1980; Barrett et al., 1995; Fisher and Jarret, 1984). Thus, results from model studies to date are

suspect and need to be modified to account for the impacts of clogging on flow rate. Barfield et

al., (2000) developed a model of flow rate using conditional probability concepts, but the results

have not been experimentally verified. 

Design aids have been developed for silt fence, using simulations from the SEDIMOT III model

(Hayes and Barfield, 1995). In the model, predictions are made about trapping efficiency using

the ratio of settling velocity for the d151 of the eroded sediment, divided by the ratio of discharge

to ponded surface area. The design aids yield conservative estimates as compared to the

SEDIMOT III model, but the database used for generating the design aid is based on the

assumption that clogging does not impact flow rates. The discussion above shows that

assumption to be erroneous. 

The bottom line on the discussion above is that it is not possible to predict with any expected

accuracy the trapping efficiency of silt fence under a given set of conditions.

Installation Criteria

General installation criteria for the silt fence should incorporate the following factors:
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• The fabric must have sufficient strength to counter forces created by contained water and

sediment (Sprague, 1999).

• The posts must have sufficient strength to counter the forces transferred to them by the fabric

(Sprague, 1999).

• The fabric must be installed to ensure that the loads are all adequately transferred through the

fabric to the posts or the ground without overstressing (Sprague, 1999).

• The fence must be designed based on site-specific hydrologic and soil conditions such that it

will not overtop during design events. 

• The fence must be installed (anchored) with a buried toe of sufficient depth so that it does

not become detached from the soil surface.

• In general, the fence requires a metal wire backing to provide sufficient strength to prevent

failure from the weight of trapped sediment and to prevent the toe of the fabric from being

removed from the ground.

• Maximum drainage area behind the fence should be determined based on the local rainfall

and the infiltration characteristics of the soil and cover.

Silt fence material is typically synthetic filter fabric or a pervious sheet of polypropylene, nylon,

polyester, or polyethylene yarn. The fabric should have ultraviolet ray inhibitors and stabilizers

to provide for a minimum useful construction life of 6 months or the duration of construction,

whichever is greater. The height of the fence fabric should not exceed 3 feet. If standard

strength filter fabric is used, it should be reinforced with a wire fence, extending down into the

trench that buries the toe. The wire should be of sufficient strength to support the weight of the

deposited sediment and water. In general, a minimum 14 gauge and a maximum mesh spacing

of 6 inches is called for (Smolen et al., 1988). Typical requirements for the silt fence physical

properties, as specified in selected local BMP standards and specifications, are included in Table

5-14. 
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Table 5-14. Typical Requirements for Silt Fence Fabric

Physical Property

Requirements

Woven Fabric Non-Woven Fabric

Filtering Efficiency 85% 85%

Tensile Strength at

20% (maximum)

Elongation

Standard Strength —30

pound/linear inch

Extra Strength —50 pound/linear

inch 

Standard Strength —50 pound/linear

inch

Extra Strength —70 pound/linear inch

Slurry Flow Rate 0.3 gallon/square feet/minute 4.5 gallon/square feet/minute

Water Flow Rate 15 gallon/square feet/minute 220 gallon/square feet/minute

UV Resistance 70% 85%

Source: NCDNR, 1988; IDNR 1992.

It should be pointed out that these numbers, particularly the flow rates, could vary widely

depending on the local soil condition due to possible clogging of the filter material. 

Material for the posts used to anchor the filter fabric can be constructed of either wood or steel.

Wooden stakes should be buried at a depth sufficient to keep the fence, when loaded with

sediment and water, from falling over. The depth of burial should depend on soil strength

characteristics when saturated and post diameter. Many standards and specifications set a

minimum length of the post of 5 feet long, and a diameter of 4 inches for posts composed of

softwood (e.g, pine), and 2 inches for posts composed of hardwood (e.g., oak)(Smolen et al.,

1988). Steel posts should also be designed based on local soil strength characteristics when wet. 

Some standards and specifications for these posts set a minimum weight of 1.33 pound/linear

feet with a minimum length of 4 feet. Steel posts should also have projections to adhere filter

fabric to the post (Smolen et al., 1988). 

A silt fence should be erected in a continuous fashion from a single roll of fabric so as to

eliminate unwanted gaps in the fence. If a continuous roll of fabric is not available, the fabric

should overlap from both directions only at posts with a minimum overlap of 6 inches and be

rolled together with a special flexible rod to keep the ends from separating. Fence posts should

be spaced at a distance based on wet soil strength characteristics and post size and strength;

generally, the posts are spaced approximately 4 to 6 feet apart. If standard strength fabric is

used in combination with wire mesh, the spacing can be larger. Typically, the standards and

specifications call for the posts to be no more than 10 feet apart. If extra-strength fabric is used

without wire mesh reinforcement, some standards call for the support posts to be spaced no more

than 6 feet apart (VDCR, 1995). Again, this spacing should depend on wet soil strength

characteristics and post size. 

A silt fence must provide sufficient storage capacity or be stabilized over flow outlets such that

the storage volume of water will not overtop the fence. The return period event (size of the

rainfall event managed) used for design is typically a prerogative of the regulatory agency. For

temporary fences, a 2-year storm event is typically used as a design standard. Fences that will be

in place for 6 months or longer are commonly designed based on a 10-year storm event
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(Sprague, 1999). The space behind the fence used for impoundment volume must be sufficient

to adequately contain the sediment that will be deposited. Each storm will deposit sediment

behind the fence, and after a period of time the amount of sediment accumulated will render the

fence useless. Frequency of fence management is a function of its sizing (i.e. whether the fence

was installed for a 2-year or a 10-year storm event) (Sprague, 1999) and the amount of erosion

that occurs in the area draining to the fence. 

Effectiveness

The performance of silt fences has not been well defined. Laboratory studies using carefully

controlled conditions have shown trapping efficiencies in the range of 40 to 100 percent,

depending on the type of fabric, overflow rate, and detention time (Barrett et al., 1995; Wyant,

1980; Wishowski et al., 1998). Field studies have been limited and quite inadequate; however,

the results show that field-trapping efficiencies are very low. In fact, Barrett et al. (1995)

obtained a value of zero percent trapping averaged over several samples with a standard error of

26 percent. Barrett et al. (1995) cite the following reasons for the field tests not showing the

expected results:

• Inadequate fabric splices

• Sustained failure to correct fence damage resulting from overtopping

• Large holes in the fabric

• Under-runs due to inadequate “toe-ins”

• Silt fence damaged and partially covered by the temporary placement of stockpiles of

materials

Field inspections conducted by Barfield and Hayes (1992) were made in which more than 50

construction sites in South Carolina and Kentucky were visited. Inspections found that silt fence

was seldom installed and, when installed, was rarely set up according to specifications. In areas

where installations did meet standards, it was obvious that flows sought the weakest spot on the

fence and either flowed through cuts in the fabric, or undercut or overtopped the fence. This

flow was thus changed from the overland flow coming into the site to concentrated flow, causing

significant erosion.

Silt fences are effective at removing large particle sediment, primarily aggregates, sands, and

larger silts. Sediment is removed through impounding of water to slow velocity. It is argued

that the silt fence will not contribute to a reduction in small particle sediment and is not effective

against other pollutants (WYDEQ, 1999). EPA (1993) reports the following effectiveness

ranges for silt fences constructed of filter fabric: average total suspended solids removal of 70

percent, sand removal of 80 to 90 percent, silt-loam removal of 50 to 80 percent, and
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silt-clay-loam removal of 0 to 20 percent. However, the EPA numbers from the Nationwide

Urban Runoff Program should not be considered to apply to every location. 

The actual trapping will vary widely for a given design because of differences in hydrologic

regimes and soil types.

The advantages of using silt fences include: minimal labor requirement for installation, low

cost, high efficiency in removing sediment, durability, and sometimes reuse (Sprague, 1999). 

Silt fences are the most readily available and cost-effective control options where options like

diversion are not possible. Silt fences are also a popular choice; because contractors have used

them extensively, the familiarity makes silt fence use more likely for future construction

activities. The visibility of a silt fence is also an advantage, for the fence is “advertising” the use

of erosion and sediment control structures. In addition, the silt fence visibility makes site

inspection easier for contractors and government inspectors (CWP, 1996).

Limitations 

Silt fences should not be installed along areas where rocks or other hard surfaces will prevent

uniform anchoring of fence posts and entrenching of the filter fabric because an insufficient

anchor will greatly reduce the effectiveness of silt fencing and may create runoff channels

leading off-site. In addition, open areas where wind velocity is high may present a maintenance

challenge, as high winds may accelerate deterioration of the filter fabric (Smolen et al., 1988).

When the pores of the silt fence fabric become clogged with sediment, pools of water are likely

to form on the uphill side of fence. Siting and design of the silt fence should account for this

problem and care should be taken to avoid unnecessary diversion of storm water from these

pools which might cause further erosion damage. Silt fences can act as a diversion if placed

slightly off-contour and can control shallow, uniform flows from small, disturbed areas and

deliver sediment-laden water to deposition areas. 

Silt fences will sag or collapse if a site is too large, if too much sediment accumulates, if the

approach slope is too steep, or if the fence was not adequately supported. If the fence bottom is

not properly installed or the flow velocity is too fast, fence undercuts or blowouts can occur

because of excess runoff. Erosion around the end of the fence can occur if the fence ends do not

extend upslope to prevent flow around the fence (IDNR, 1992). 

Maintenance 

Site operators should inspect silt fences after each rainfall event to ensure they are intact and that

there are no gaps at the fence-ground interface or tears along the length of the fence. If gaps or

tears are found, they should be repaired or the fabric should be replaced immediately. 

Accumulated sediments should be removed from the fence base when the sediment reaches

one-third to halfway up the height of the fence. Sediment removal should occur more frequently

if accumulated sediment is creating a noticeable strain on the fabric and there is the possibility

that the fence might fail from a sudden storm event. 
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Cost

There is a wide range of data on installation costs for silt fences. EPA estimates these costs at

approximately $6.00 per linear foot (USEPA, 1992) while SWRPC estimates unit costs between

$2.30 and $4.50 per linear foot (SWRPC, 1991). Silt fences have an annual maintenance cost

that is 100 percent of installation cost (Brown et al., 1997). These values are significantly greater

than that reported by R. S. Means (2000), which indicates a 3 foot tall silt fence installation cost

between $0.68 and $0.92 per linear foot (for favorable and challenging installations). It should

be noted that the R. S. Means value covers just a single installation, without the expected costs

of maintenance (e.g., removal of collected sediment). In addition, the type of silt fence fabric

employed will also affect the total installation costs.

5.1.5.3.2 SUPER SILT FENCE

General Description

Super silt fence is a modification of a standard silt fence. The two central differences between

the standard silt fence and the super silt fence is that the super silt fence has toe that is buried

more deeply and the backing material is chain link fence held in place by steel posts–a concept

that originated in Maryland. The Maryland super silt fence requires a Geotextile Class F fabric

over a chain link fence to intercept sediment-laden runoff from small drainage areas. The super

silt fence provides a barrier that can collect and hold debris and soil more effectively than a

standard silt fence, preventing material from entering critical areas. It is best used where the

installation of a dike would destroy sensitive areas, woods, and wetlands. 

Applicability 

Super silt fences can be used in the same conditions as a silt fence. Fences should follow the

contour of the land. Table 5-15 lists the distance a super silt fence should be from a slope to

ensure maximum effectiveness (MDE, 1994). 

Table 5-15. Slope Lengths for Super Silt Fences

Slope (%)

Slope Length 

Minimum Maximum

 0-10 Unlimited Unlimited

10-20 200 feet 1,500 feet

20-33 100 feet 1,000 feet

33-50 100 feet 500 feet 

50+ 50 feet 250 feet
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Design and Installation Criteria 

As with the standard silt fence, design criteria are of two types, hydrologic design for a required

trapping of sediment and flow rate to pass the design storm and selection of appropriate

installation criteria such that the silt fence will perform as designed. 

Hydrologic Design

Hydrologic design criteria are the same as the criteria for the standard silt fence. 

Installation Criteria

The criteria used for the Maryland super silt fence indicate the following, although they have not

been tested with field data:

• The fence should be placed as close to the contour as possible, with no section of the silt

fence exceeding a grade of 5 percent for a distance of more than 50 feet.

• Fabric should be no more than 42 inches in height and should be held in place with a 6-foot

chain link fence.

• Fabric should be attached to the steel pole using wire ties or staples. Fabric should be

securely fastened to the chain link fence with ties spaced every 24 inches at the top and

midsection.

• Fabric should be embedded into the ground at a minimum of 8 inches.

• Edges of fabric should overlap by 6 inches. 

Table 5-16 describes the physical properties of Geotextile class F fabric (MDE, 1994). 

Table 5-16. Minimum Requirements for Super Silt Fence Geotextile Class F Fabric

Physical Properties Requirements

Tension Strength 50 pound/inch

Tensile Modulus 20 pound/inch

Flow Rate 0.3 gallon/ft2/minute

Filtering Efficiency 75%
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Effectiveness

Performance data have not been collected for super silt fences. The fences have been proposed

for locations within a sensitive watershed, or where site conditions prohibit the use of a standard

silt fence. However, until performance data are collected under field conditions, effectiveness is

speculative.

Limitations

Super silt fences are not as likely to fail structurally as are standard silt fences, but they are more

expensive than standard silt fences. 

Maintenance

Maintenance requirements for super silt fences are generally the same as for standard silt fences. 

Cost

The cost of the super silt fence is more than the standard silt fence because of deeper burial at the

toe and the cost of chain linked fencing. R. S. Means (2000) indicates a rental price of $10 to $11

per linear foot of chain linked fence for periods up to 1 year. Overall, rental is expected for most

construction site installation because rental rates are approximately half the price of permanent

chain link fencing.

5.1.5.3.3 STRAW BALE DIKE

General Description

The straw bale dike is a temporary measure used to trap sediment from small, sloping disturbed

areas. It is constructed of straw bales (not hay bales) wedged tightly together and placed along

the contour downslope of disturbed areas. The bales are placed in a shallow excavation, and the

upslope side is sealed with soil. Stakes are driven through the bales into the soil to help hold the

bales in place. The dike works by impounding water, which allows sediment to settle out in the

upslope area (Haan et al., 1994). Straw bale dikes are recommended for short duration

application and are usually effective for less than 3 months because of rapid decomposition

(USDOT, 1995).

Applicability

Straw bale dikes are generally placed at the toe of fills to provide for a broad shallow sediment

pool. The dikes should not be used in drainage areas with concentrated and high flows, in large

areas, or in ditches and swales. The location of the straw bale dike should be fairly level, at least
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10 feet from the toe, and should follow the land contour. Table 5-17 lists the distance a straw

bale dike should be placed from a slope to ensure maximum effectiveness.

Table 5-17. Maximum Land Slope and Distances Above a Straw Bale Dike

Land Slope (%) Maximum Distance Above Dam (ft)

Less than 2 100 

2-5 75

5-10 50

10-20 25

More than 20 15

Source: USDOT, 1995.

Design and Implementation Criteria

Hydrologic Design

Hydrologic design dictates the structure necessary to withstand a storm without causing damage

while trapping the required amount of sediment. Either a database or some type of model are

needed to find the appropriate design. Efforts to model the sediment trapping that occurs in

straw bale dikes have resulted in models that predict the settling in the ponded area upstream

from the fence (Barfield et al., 1996; Lindley et al., 1998). The results from model simulations

show that trapping depends primarily on the surface area of the impounded water and flow rate

through the filter. The models utilize a clear water slurry flow rate to predict discharge. It is

anticipated, based on visual observations, that sediment will clog the straw bale barrier, reducing

the slurry flow rate. Thus, results from model studies to date are suspect and need to be

modified to account for the impact of clogging on flow rate. 

Installation Criteria

The USDOT’s BMP Manual and the Indiana BMP Manual (IN Manual) calls for bales to be:

• Anchored by driving two 36-inch long (minimum) steel rebars or 2 x 2-inch hardwood stakes

through each bale;

• Sized according to the standard bale size of 14 inches x 18 inches x 35 inches; 

• Placed in an excavated trench at least 4 inches deep, a bale’s width, and long enough that the

end bales are somewhat upslope of the sediment pool;

• Abutted tightly against each other; and, 

• Sized such that impounded water depth should not exceed 1.5 feet. 
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The USDOT BMP Manual does not require that straw bale dikes be designed; however, the

Indiana Manual limits the drainage area to 1⁄4 acre per 100 feet of dam and the total drainage area

draining to a straw bale dike to 2 acres.

Effectiveness

The information on performance of straw bale dikes is very limited. In laboratory studies of

bales at varying orientations, Kouwen (1990) found that trapping efficiencies ranged from 60 to

100 percent. Field data on trapping have not been collected; however, visual inspection of sites

indicate that straw bales are not properly installed to prevent flows from undercutting or flowing

between bales (Barfield and Hayes, 1992, 1999). In addition, bales deteriorate rapidly and need

to be replaced frequently. Because of these problems, the use of straw bale dikes as a perimeter

control is not recommended, except in special circumstances. Only 27 percent of Erosion and

Sediment Control (ESC) experts rated the straw bale dike as an effective ESC practice, although

its use was still allowed in half of the communities surveyed (Brown and Caraco, 1997).

Limitations

Straw bale dikes should not be used as a diversion, in streams, in channels, or in areas with

concentrated flow. The bales are not recommended for paved areas because of the inability to

anchor the bales (IDNR, 1992). 

Care must be taken to ensure that the bales are not installed in an area where there is a

concentrated flow of runoff, in a drainage area that is too large, or on an excessive slope (IDNR,

1992). Under these conditions, erosion around the end of the bales, overtopping and

undercutting of the bales, and bale collapsing and dislodging are likely to occur. Overtopping

will also occur if the storage capacity is underestimated and where provisions are not made for

safe bypass of storm flow (IDNR, 1992). Undercutting will occur if the bales are not

entrenched at least 4 inches and backfilled with compacted soil or were not abutted or chinked

properly. Straw bale dikes are likely to collapse or dislodge if the bales are not adequately

staked, or if too much sediment is allowed to accumulate before cleanout (IDNR, 1992).

Maintenance 

For the straw bale dike to be most effective, it is important to replace deteriorated bales when

appropriate. 

Cost

The cost of straw bale dikes are relatively low, making their use relatively attractive. R. S.

Means (2000) indicates a staked straw bale unit cost of $2.61 per linear foot (Costs include

materials, labor, and equipment, with profit and overhead). 
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5.1.5.3.4 SEDIMENT TRAP

General Description

A sediment trap is a temporary control device used to intercept sediment-laden runoff and to trap

sediment to prevent or reduce off-site sedimentation. It is normally a more temporary type of

structure than a sediment pond and is constructed to control sediment on the construction area

during a selected phase of the construction operation. A sediment trap can be formed by

excavation and/or embankments constructed at designated locations accessible for cleanout. The

outlet for a sediment trap is typically a porous rock fill structure, which serves to detain the flow,

but a pipe structure can also be used. A temporary sediment trap may be located in a

drainageway, at a storm drain inlet, or at other points of discharge from a disturbed area. They

may be constructed independently or in conjunction with diversions and may be used in most

drainage situations to prevent excessive siltation of pipe structures (USEPA, 1992). 

Applicability

Sediment traps can simplify the storm water control plan design process by trapping sediment at

specific spots at a construction site (USEPA, 1992). They should be installed as early in the

construction process as possible and are primarily effective as a short-term solution to trapping

sediment from construction sites (WYDEQ 1999). Natural drainage patterns should be noted,

and sites where runoff from potential erosion can be directed into the traps should be selected. 

Traps are most effective when capturing runoff from areas where 2 to 5 acres drain to one

location. Sediment traps should not be located in areas where their failure resulting from excess

storm water runoff can lead to further erosive damage of the landscape. Alternative diversion

pathways should be designed to accommodate these potential overflows. Traps should be

accessible for clean-out and located so that they do not interfere with construction activity. In

addition, the traps are easily adaptable to most conditions.

Design and Implementation Criteria

Hydrologic Design

A sediment trap should be designed to maximize surface area and sediment settling. This will

increase the effectiveness of the trap and decrease the likeliness of backup during and after

periods of high runoff intensity. The design of a trap includes determining the storage volume,

surface area, dimensions of spillway or outlet, and elevations of embankment (USDOT, 1995). 

Sediment traps should be designed to meet a 2- year, 24-hour duration storm event, but the

selection of a return period varies among regulatory agencies (IDNR, 1992).

Storage volume is created by a combination of excavation of land and construction of an

embankment to detain runoff (USDOT, 1995). Trap storage volume and length of spillway are

determined as a function of the runoff volume and rate for the design storm. These parameters
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will vary depending on return period rainfall and watershed hydrologic characteristics. Some

standards specify a storage volume per acre disturbed. For example, Smolen et al. (1998)

specified that approximate storage capacity of each trap should be at least 67 cubic yards per

acre disturbed draining into the trap, but more recent guidelines suggest 134 cubic yards per acre

of drainage area (VDCR, 2001). Any national standard, however, should be based on runoff

volume and peak discharge in order to be generally applicable. Local regulations can translate

this into applicable volume and area standards. 

A more important criterion than storage volume relates to sediment trapping. If a trapping

efficiency is specified, as in the case of South Carolina (SCDHEC, 1995), it is necessary to

design for trapping efficiency. If a TSS or settleable solids effluent criterion is adopted

(SCDHEC, 1995), settleable solids must be estimated. In both cases, a national standard should

address how to estimate trapping efficiency or settleable solids. Efforts to model the sediment

trapping that occurs in sediment traps have resulted in models that predict the settling in the

ponded area (Barfield et al., 1996; Lindley et al., 1998). The results from model simulations

show that trapping depends primarily on surface area of the impounded water and flow rate

through the rock fill outlet. In fact, the ratio of peak outflow rate to surface area is the best

simple predictor of trapping. The models utilize a modification of the Herrera and Felton (1991)

relationship developed by Haan et al. (1994) to predict discharge rates. The predicted flow rates

do not take into account clogging that can occur in rock fill. No models or procedures are

available to estimate this clogging or its impact on flow criteria.

Design aids have also been developed for sediment traps, using simulations from the 

SEDIMOT III (Barfield et al., 2001; Hayes et al., 2001). In the model, predictions are made of

trapping efficiency using the ratio of settling velocity for the d15 of the eroded sediment, divided

by the ratio of discharge to ponded surface area. The design aid yields conservative estimates,

but the database used for generating the design aid is based on the assumption that flow rates are

not impacted by clogging. This latter assumption is not likely to be a critical issue, but should be

addressed in future research. 

Installation Specifications

USDOT standards call for the embankment to be constructed of compacted earth, at a maximum

height of 5 feet (1.5 meters), a width of 4 to 5 feet (1.2 meters), and side slopes of 2:1or flatter. 

These values may change as a result of local criteria and with changing soil characteristics. 

Temporary vegetation should be applied to the embankment (USDOT).
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Two types of outlet structures are typically used for sediment traps, a rock outlet and a pipe

outlet. Spillways of large stones or aggregate are the most common type of outlet designed for

sediment traps. The crest of the spillway should be constructed 1 foot below the top of the

embankment and the spillway depth 1.5 feet below the top of the embankment. Weir length of

the spillway is determined based on the contributing drainage area (Table 5-18) (USDOT, 1995).

The outlet apron should be a minimum of 5 feet long, and situated on level ground with a filter

fabric foundation to ensure exit velocity of drainage to receiving stream is nonerosive (IDNR,

1992).

The length of the rock outlet should be determined based on peak discharge required and rock

characteristics, typically rock diameter. Flow rate calculations can be made with the relationship

of Herrera and Felton (1991) as modified by Haan et al. (1994). Alternatively, the USDOT has

specified the weir length for a given drainage area as shown in Table 5-18. However, the values

should be adjusted for each climatologic area to account for local hydrologic and return period

rainfall.

Table 5-18. Weir Length for Sediment Traps

Contributing

Drainage Area Weir Length (ft)

1 4

2 5

3 6

4 10

5 12

Source: USDOT, 1995.

The pipe outlet, constructed of corrugated metal or PVC pipe riser, is an alternative to the rock

outlet. Pipe diameter is based on the peak discharge rate required. To obtain appropriate

freeboard, the top of pipe should be placed 1.5 feet below embankment elevation. Perforated

pipe is sometimes used. USDOT suggests perforations of 1- inch (25 mm) diameter holes or 

0.5 x 6 inch (13 x 15 mm) slits in the upper two-thirds of the pipe; however, the discharge should

be calculated for this pipe specification to ensure that it matches the required peak discharge.

The pipe should be placed vertically and horizontally above wet storage elevation 

(USDOT, 1995). Riprap should be used as an outlet protection and placed at the outlet of the

barrel to prevent scour from occurring (USDOT, 1995). A stable channel should be provided to

convey discharge to the receiving channel (USDOT, 1995). 

Effectiveness

If it is assumed that the flow can be accurately controlled by the rock fill outlet, sediment traps

should operate as effectively as sediment basins, with trapping efficiencies reduced as a result of

smaller surface areas. The NURP study (USEPA, 1993), Stahre and Urbonas (1990), and 
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Haan, et al., (1994), report that sediment basins effectively trapped sediment and chemical as

shown in Table 5-19.

Table 5-19. Range of Measured Long-Term Pollutant Removal for 

Sediment Detention Basins 

Item Removable Percentage

Total suspended solids (TSS) 50-70

Total phosphorus (TP) 10-20

Nitrogen 10-20

Organic matter 20-40

Lead 75-90

Zinc 30-60

Hydrocarbons 50-70

Bacteria 50-90

Source: Stahre and Urbonas, 1990.

Information on the actual effectiveness of sediment trapsis limited. The discussion should start

first with the flow hydraulics of the rock fill outlet typically employed as a principal spillway for

sediment traps. Procedures for estimating flow through rock fill have been developed by Herra

and Felton (1991) to estimate flow as a function of average rock diameter, standard deviation of

rock size, and flow length. If these parameters could be controlled in an actual situation, the

flow could be accurately predicted. However, given that standard construction practices consist

of end-dumping the rock fill in place, one would expect little correlation between design and

construction and the actual discharge and trapping efficiency would be expected to be

dramatically different from the design. This analysis does not mean that sediment traps are

ineffective, but that a given design could not be guaranteed to meet the effluent criteria, even

though the predictions indicate compliance. Sediment trapping efficiency is a function of

surface area and inflow rate (Smolen, 1988). Those traps that provide pools with large length-towidth ratios have a greater chance of success.

Sediment traps remove larger size sediment, primarily sized from silt to sands, by slowing water

velocity and allowing for sediment settling in ponded water (Haan et al., 1994). Although

sediment traps allow for settling of eroded soils, because of their short detention periods for

storm water they typically do not remove fine particles such as silts and clays without chemical

treatment. Sediment settling ability is related to the square of the particle size; halving particle

sizes quadruples the time needed to achieve settlement (WYDEQ 1999). To increase overall

effectiveness, traps should be constructed in smaller areas with low slopes.

Sediment traps are typically designed to remove only sediment from surface water, but some

non-sediment pollutants are trapped as well (Haan et al., 1994). 
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Limitations

Common concerns associated with sediment traps are included in Table 5-20.

Table 5-20. Common Concerns Associated with Sediment Traps

Common Concern Result

Inadequate spillway size Results in overtopping of the dam and possible failure

of the structure

Omission or improper installation of geotextile fabric Results in piping under the sides or bottom of the stone

and outlet section

Low point in embankment caused by inadequate

compaction and settling

Results in overtopping and possible failure

Stone outlet apron does not extend to stable grade Results in erosion below the dam

Stone size too small or backslope too steep Results in stone displacement

Inadequate vegetative protection Results in erosion of embankment

Inadequate storage capacity Caused by sediment not being removed from the basin

enough

Contact slope between stone spillway and earth

embankment too steep

Results in piping failure

Outlet pipe installed in vertical side of trench Results in piping failure of embankment

Corrugated tubing used as outlet pipe Results in crushed pipe and inadequate outlet capacity

Source: IDMR, 1992.

Maintenance

The primary maintenance consideration for temporary sediment traps is the removal of

accumulated sediment from the basin, which must be done periodically to ensure the continued

effectiveness of the sediment trap. Sediments should be removed when the basin reaches

approximately 50 percent sediment capacity.

A sediment trap should be inspected after each rainfall event to ensure the trap is draining

properly. Inspectors should also check the structure for damage from erosion or piping. The

depth of the spillway should be checked and maintained at a minimum of 1.5 feet below the low

point of the trap embankment. 

Cost

The cost of installing temporary sediment traps ranges from $0.20 to $2.00 per cubic foot of

storage (about $1,100 per acre of drainage). For a recent national assessment, USEPA (1999)

estimated the following costs for sediment traps, which vary as a function of the volume of

storage: $513 for 1,800 cubic yards, $1,670 for 3,600 cubic yards, and $2,660 for 5,400 cubic

yards. In addition, it has been reported that a sediment trap has an annual maintenance cost of 20

percent of installation cost (Brown et al., 1997).
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5.1.5.3.5 SEDIMENT BASINS

General Description

A sediment basin is a storm water detention structure formed by constructing a dam across a

drainageway or excavating a storage volume at other suitable locations and using it to intercept

sediment-laden runoff. Sediment basins are generally larger and more effective in retaining

sediment than temporary sediment traps and typically remain active throughout the construction

period. Jurisdictions that require postdevelopment flow to be less than or equal to

predevelopment flow during construction may employ the designed detention facilities as a

temporary sediment basin during construction.

When sediment basins are designed properly, they can control sediment pollution through the

following functions (Faircloth, 1999):

• Sediment-laden runoff is caught to form an impoundment of water and create conditions

where sediment will settle to the bottom of the basin.

• Treated runoff is released with less sediment concentration than when it entered the basin.

• Storage is provided for accumulated sediment, and resuspension by subsequent storms is

limited.

Applicability

Sediment basins should be located at a convenient concentration point for sediment-laden flows

(NCDNR, 1988). Ideal sites are areas where natural topography allows a pond to be formed by

constructing a dam across a natural swale; such sites are preferred to those that require

excavation (Smolen et al., 1998).

Sediment basins are also applicable in drainage areas where it is anticipated that other erosion

controls, such as sediment traps, will not be sufficient to prevent off-site transport of sediment. 

Choosing to construct a sediment basin with either an earthen embankment or a stone/rock dam

will depend on the materials available, location of the basin, and desired capacity for storm water

runoff and settling of sediments.

Rock dams are suitable where earthen embankments would be difficult to construct or where

riprap is readily available. Rock structures are also desirable where the top of the dam structure

is to be used as an emergency overflow outlet. These riprap dams are best for drainage areas of

less than 50 acres. Earthen damming structures are appropriate where failure of the dam will not

result in substantial damage or loss of property or life. If properly constructed, sediment basins

with earthen dams can handle storm water runoff from drainage basins as large as 100 acres.
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Design and Implementation Criteria

Hydrologic Design

A sediment basin can be constructed by excavation or by erecting an earthen embankment across

a low area or drainage swale. Sediment basins can be designed to drain completely during dry

periods, or they can be constructed so that a shallow, permanent pool of water remains between

storm events. Depending on the size of the basin constructed, the basin may be subject to

additional regulation, particularly state and federal regulations related to dam safety. 

Sediment basins can be used for any size watershed, but the U.S. Department of Transportation

recommends a drainage area range of 5 to 100 acres (USDOT, 1995). Components of a sediment

basin that must be considered in the hydrologic design include the following (Haan et al., 1994):

• A sediment storage volume sized to contain the sediment trapped during the life of the

structure or between cleanouts. 

• A permanent pool volume (if included) above the sediment storage to protect trapped

sediment and prevent resuspension as well as providing a first flush of discharge that has

been subjected to an extended detention period. 

• A detention volume that contains storm runoff for a period sufficient to trap the necessary

quantity of suspended solids. 

• A principal spillway that can be a drop-inlet pipe and barrel, a trickle tube, or other type of

controlled release structure.

• An emergency spillway that is designed to handle excessive runoff from the rarer events and

prevent overtopping.

The following recommended procedures for conducting the hydrologic design are summarized

from Haan et al. (1994).

Sediment Storage Volume. This volume should be sufficient to store the sediment trapped

during the life of the structure or between cleanouts. Sediment storage volume can be calculated

based on sediment yield using relationships such as the Revised Universal Soil Loss Equation

with an appropriate delivery ratio (Renard et al., 1994) or a computer model such as 

SEDIMOT III (Barfield et al., 1996). Many design specifications, however, base the sediment

storage volume on a volume per acre disturbed. This volume is highly site-specific, depending

on rainfall distributions, soil types, and construction techniques. It is recommended that care be

exercised in developing appropriate values to be sure that existing variations in rainfall

throughout a state or region are incorporated in the statutory requirements.
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Permanent Pool Volume. Providing a first flush of discharge that has been subjected to an

extended detention period can help to minimize degradation of water quality and justify some

permanent pool. The recommended capacity of the permanent pool varies with the regulatory

agency. The U.S. Department of Transportation, for example, recommends 67 cubic yards per

acre (126 m3/ha) (USDOT, 1995). If an effluent criterion such as allowable peak TSS or peak

settleable solids is used, the final design of both permanent pool and detention volume should be

selected only after using a computer model to predict the expected peak effluent concentrations.

Detention Volume. Storm runoff must be contained for a period of time sufficient to trap the

necessary quantity of suspended solids. Since inflow is occurring simultaneously with outflow,

the detention time for each plug of flow is different and should be considered individually. The

size of the detention volume, as stated above, should also be developed in concert with

determining the size of the permanent pool volume as well as the size of the principal spillway. 

When effluent TSS and settleable solids criteria are used, the size of the detention volume and

permanent pool volume should be determined through on a computer model calculation of

expected effluent concentrations for a given design. The return period used to size the detention

volume depends on the regulatory agency, but a return period of 10 years is typical.

Principal Spillway. The principal spillway is a hydraulic outlet structure sized to provide the

appropriate outflow rate to meet the effluent or trapping efficiency criteria. The principal

spillway should have a dewatering device that slowly releases water contained in the detention

storage over an extended period of time and at a rate determined to trap the required amount of

sediment and/or provide for the appropriate effluent concentration in the design storm. The

more common outlet structures are the drop-inlet structure and the trickle tube. Sizing of the

principal spillway should follow standard hydrologic and sedimentology design procedures but 

sizing the structure to simply pass the design storm is inappropriate and will not result in

meeting an effluent or trapping efficiency standard. The size to be used in a given structure

should be determined based on the effluent or trapping efficiency standard being targeted and

site-specific hydrologic and soil conditions. Appropriate design will require the use of a

computer model such as SEDIMOT III (Barfield et al., 1996) or design aids such as those

developed for South Carolina (Hayes and Barfield, 1995). In general, the design is developed to

maximize surface area, which will minimize peak discharge. Since failure of the dam could

result in downstream damage, the design should be done and certified by a licensed engineer

with expertise in hydrologic computation. 

It has been proposed that a surface skimmer made of PVC, aluminum, or stainless steel and

designed to prevent trash from clogging and can also be used to replace conventional principal

spillways. The skimmer puts the basin drain just below the water surface, allowing for a

constant head rather than variable head from the bottom. It is proposed that the skimmer allows

water to be released from the top of the basin, which would be the cleanest water, and that the

skimmer properly regulates the fill and draining of the basin (Fairchild, 1999). The skimmer

floats on the surface of the basin and rises as water in the basin rises during the storm. After the

storm the skimmer slowly releases water from the basin. As the basin drains, the skimmer
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settles to the bottom, draining the entire pool except for a pool directly under the skimmer. The

skimmer can be attached directly to an outlet pipe that drains through the dam or can be attached

to an outlet pipe through a riser. It is important to point out that use of the skimmer is

controversial and not universally recognized as a good concept. Conventional hydraulic flow

theory would not concur with the statement that the flow would come only from the surface,

unless the pond had significant thermal gradients preventing flow from deeper levels. A single

hole placed just above the sediment cleanout level can also dewater the basin slowly.

Emergency Spillway. Since overtopping of the dam can cause failure and downstream damage,

an emergency spillway is necessary to handle excessive runoff from the rarer events and prevent

overtopping. The design storm for the emergency spillway will depend on the hazard

classification of the sediment basin. Typical return periods vary between 25 and 100 years, with

25 years recommended by the USDOT. Sizing of the emergency spillway is typically

accomplished to simply transmit the rare event without eroding the base of the spillway. 

Procedures for making the hydrologic and hydraulic computations are summarized in Haan et al.

(1994). Again, since failure of the dam could result in downstream damage, the design should

be done and certified by a licensed engineer with expertise in hydrologic computation.

Installation Criteria

The embankment for permanent sediment basins should use standard geotechnical construction

techniques. The fill is typically constructed of earthen fill material placed and compacted in

continuous layers over the entire length of the fill. USDOT recommends 6- to 8- inch layers

(USDOT, 1995). The embankment should be stabilized with vegetation after construction of the

basin. A cutoff trench should be excavated along the centerline of the dam to prevent excessive

seepage beneath the dam, and sized using standard geotechnical computations. USDOT

recommends that a minimum depth of the cutoff trench should be about 2 feet (600 mm), the

height should be to the riser crest elevation, the minimum bottom width should be 4 feet (1.2 m)

or wide enough for compaction equipment, and slopes should be no steeper than 1:1. 

Sediment basins can also be constructed with rock dams in a design that is similar to a sediment

basin with an earthen embankment. It is important to remember that rock fill is highly

heterogeneous and that flow rates calculated with any available procedure are not likely to match

those that will actually occur. Since sediment trapping is inversely proportional to flow rate, the

trapping efficiency will be impacted significantly. No data are available to determine the

variability of rock fill in actual installations so that confidence intervals can be placed on

predicted flow rates. Such data should be collected and the confidence intervals calculated prior

to recommending the use of rock dams as outlets on any structures other than sediment traps.

Effectiveness

The effectiveness of a sediment basin depends primarily on the sediment particle size and the

ratio of basin surface area to inflow rate (Smolen et al., 1998; Haan et al., 1994). Basins with a
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large surface area-to-volume ratio will be most effective. Studies by Barfield and Clar (1985)

showed that a surface area-to-peak discharge ratio of 0.01 acres per cubic square foot would trap

more than 75 percent of the sediment coming from the Coastal Plain and Piedmont regions in

Maryland. This efficiency might vary for other regions of the country and should not be used as

a national standard. Studies by Hayes et al. (1984) and Stevens et al. (2001), however, show that

similar relationships can be developed for other locations. 

Laboratory data collected on pilot-scale facilities are available on the trapping efficiency of

sediment basins, on effluent concentrations, on dead storage and flow patterns, and on the

impacts of chemical flocculants on sediment trapping (Tapp et al., 1981; Wilson et al., 1984;

Griffin et al., 1985; Jarrett et al., 1999; Ward et al., 1977, 1979). In general, the laboratory

studies show that pilot-scale ponds can be expected to trap from 70 to 90 percent of sediment,

depending on the sediment characteristics, pond volume, and flow rate. The trapping efficiency

and effluent concentration are, in general, related to the overflow rate and can be reasonably well

predicted using a plug flow model (Ward et al., 1977, 1979) and a Continuously Stirred Tank

Reactor (CSTR) model (Wilson et al., 1982; Wilson et al., 1984). Extensive field-scale data are

available on long term trapping efficiency in storm water detention basins (Brune, 1953) in

which the annual trapping efficiency is related to the annual capacity inflow ratio of the basin.

These structures are not representative of those used for sediment ponds, but would be

representative of those used for regional detention. A more limited database is available on

single storm sediment trapping in the larger structures (Ward, et al., 1979) and on a field

laboratory structure at Pennsylvania State University (Jarret et al., 1999).

For maximum trap efficiency, Smolen et al. (1988) recommend the following:

• Allow the largest surface area possible, maximize the length-to-width ratio of the basin to

prevent short circuiting, and ensure use of the entire design settling area;

• Locate inlets for the basin at the maximum distance from the principal spillway outlet;

• Allow the maximum reasonable time to detain water before dewatering the basin; and,

• Reduce the inflow rate into the basin and divert all sediment-free runoff.

Jarett (1999) has shown that the smaller the depth of the basin, the more sediment is discharged. 

A 0.15 m (0.49 ft) deep basin lost twice as much sediment as a 0.46 m (1.50 ft) deep basin. 

Jarrett also found that the performance of a sediment basin will increase with the use of a

skimmer in the principal spillway. The sediment discharged was 1.8 times greater with just a

perforated riser than with a skimmer in the principal spillway. In addition, increasing the dewatering time, which will allow for more sediment deposition, decreases the sediment loss from

the basin (Jarett, 1999).
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Limitations

Neither a sediment basin with an earthen embankment nor a rock dam should be used in areas of

continuously running water (live streams). The use of sediment basins is not intended for areas

where failure of the earthen or rock dam will result in loss of life, or damage to homes or other

buildings. In addition, sediment basins should not be used in areas where failure will interfere

with the use of public roads or utilities.

Because sediment basins are usually temporary structures, they are often designed poorly and

rarely receive the adequate attention and maintenance. As a result, these basins will not achieve

the function for which they were designed, especially when conventional outlets cannot properly

meter outflow to create an impoundment, thus allowing rapid release of sediment laden water

from the bottom of the basin to escape (Faircloth, 1999). 

Common concerns associated with sediment basins are included in Table 5-21.

Table 5-21. Common Concerns Associated with Sediment Basins

Common Concern Result

Piping failure along conduit Caused by improper compaction, omission of anti-seep collar,

leaking pipe joints, or use of unsuitable soil

Erosion of spillway or embankment slopes Caused by inadequate vegetation or improper grading and

sloping

Slumping or settling of embankment Caused by inadequate compaction or use of unsuitable soil

Bank failure due to slumping Caused by steep side slopes

Erosion and caving below principal spillway Caused by inadequate outlet protection

Basin not located properly for access Results in difficult, ineffective, and costly maintenance

Sediment not properly removed Results in inadequate storage capacity and potential

resuspension

Lack of anti-flotation Results in the riser and barrel being blocked with debris

Principal and emergency spillway on design

plans

Results in improper disposal of accumulated sediment 

Safety or health hazard from pond water Caused by gravel clogging the dewatering system

Principal spillway too small Results in frequent operation of emergency spillway and

increased erosion potential

Source: IDNR, 1992.

Maintenance

Routine inspection and maintenance of sediment basins is essential to their continued

effectiveness. Basins should be inspected after each storm event to ensure proper drainage from

the collection pool and determine the need for structural repairs. Erosion from the earthen

embankment or stones moved from rock dams should be replaced immediately.

Sediment basins must be located in an area that is easily accessible to maintenance crews for

removal of accumulated sediment. Sediment should be removed from the basin when its storage
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capacity has reached approximately 50 percent. Trash and debris from around dewatering

devices should be removed promptly after rainfall events.

Cost

The sediment basin has a 25 percent annual maintenance cost as a percentage of installation

(Brown et al., 1997).

If constructing a sediment basin with less than 50,000 cubic feet of storage space, the cost of

installing the basin ranges from $0.20 to $1.30 per cubic foot of storage (about $1,100 per acre

of drainage). The average cost for basins with less than 50,000 cubic feet of storage is

approximately $0.60 per cubic foot of storage (USEPA, 1993).

If constructing a sediment basin with more than 50,000 cubic feet of storage space, the cost of

installing the basin ranges from $0.10 to $0.40 per cubic foot of storage (about $550 per acre of

drainage). The average cost for basins with greater than 50,000 cubic feet of storage is

approximately $0.30 per cubic foot of storage (USEPA, 1993).

As an alternative costing method, designers can use cost curves developed for permanent basins

used to manage storm water from urban areas. However, since permanent storm water basins

typically include design features that would not be included in temporary sediment basins, this

approach is expected to greatly overestimate the actual costs to construct sediment basins. For

many sites, sedimentation basins installed for erosion and sediment control during the

construction phase are retained/modified to meet other runoff management requirements. For

example, site flood prevention requirements for the 10-year rainfall event can be met with a

pond made from a converted sedimentation basin. As a result, sedimentation basins installation

costs are partially offset by a later cost reduction or savings. Work by the Center for Watershed

Protection (CWP, 1996), provides capital cost equations for different types of sediment basins

for permanent installations. For example,

dry extended duration ponds

CC = 8.16 (Vs) ^ 0.78

and for all ponds regardless of type (including wet ponds)

CC = 20.18 (Vs) ^ 0.70

Where:

CC = base construction cost, not including design, engineering, and contingencies

Vs = Storage volume below the crest of the emergency spillway, in cubic feet
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Design, engineering, and contingency costs are given as approximately 32 percent of the base

construction costs. Base construction costs for permanent ponds are composed of approximately

48 percent excavation/grading cost, 36 percent control structure cost, and 16 percent

appurtenances cost. R. S. Means (2000) suggests the cost to remove the eroded sediment

collected in a small basin during construction is approximately $4 per cubic yard (value includes

a 100 percent surcharge for wet excavation). Disposal of material on-site will be an additional

cost that can only be computed from site-specific conditions. The cheapest management of

dredge material is application to land areas adjacent to the basin, followed with application of a

vegetative cover.

5.1.5.4 OTHER CONTROL PRACTICES

5.1.5.4.1 STONE OUTLET STRUCTURE

Description

A stone outlet structure is a temporary stone dike installed in conjunction with and as a part of an

earth dike. The purpose of the stone outlet structure is to impound sediment-laden runoff,

provide a protected outlet for an earth dike, provide for diffusion of concentrated flow, and allow

the area behind the dike to dewater slowly. The stone outlet structure can extend across the end

of the channel behind the dike or be placed in the dike itself. In some cases, more than one stone

outlet structure can be placed in a dike. 

Applicability

Stone outlet structures apply to any point of discharge where there is a need to discharge runoff

at a protected outlet or to diffuse concentrated flow for the duration of the period of construction. 

The drainage area to this practice is typically limited to one-half acre or less to prevent excessive

flow rates. The stone outlet structure should be located so as to discharge onto an already

stabilized area or into a stable watercourse. Stabilization should consist of complete vegetative

cover and paving, sufficiently established to be erosion resistant. 

Design and Installation Criteria

Design criteria are of two types, hydrologic design for a required trapping of sediment and/or

flow rate to pass the design storm; and selection of appropriate installation criteria such that the

stone outlet will perform as designed
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Hydrologic Design

The hydrologic design should be based on the design storm and standard hydraulic calculations

and should include the following considerations:

• Design Rainfall and Design Storm. The design storm should be specified by the regulatory

authority. Typically a return period of 2 to 5 years is used. Runoff rates should be calculated

with standard hydrologic procedures, as allowed by the regulatory authority.

• Drainage Area. The drainage area to this structure is typically limited to less than half an acre

to ensure that the flow rates are not excessive.

• Length of Crest and Height of Stone Fill. The crest length and height of stone fill should be

of sufficient size to transmit the design storm without overtopping. The volume of water

stored behind the dike can be estimated, but would require a routing of the storm flow in the

design storm. Flow through the stone outlet can be calculated using the relationships of

Herrera and Felton (1991) as modified by Haan et al. (1994). The height of the fill should be

small enough to prevent excessive flow velocities through the stone fill and prevent

undercutting.

• Outlet Stabilization. The discharge from the stone outlet should be stabilized with vegetated

waterways or riprap until the flow reaches a stable channel. Design of the stabilized outlet

should follow procedures presented earlier.

Installation Criteria Specifications

A stone outlet structure should conform to the following specifications:

• The outlet should be composed of 2- to 3- inch stone or recycled concrete equivalent is

preferred, but clean gravel may be used if stone is not available.

• The crest of the stone dike should be at least 6 inches lower than the lowest elevation of the

top of the earth dike and should be level.

• The stone outlet structure should be embedded into the soil a minimum of 4 inches.

• The minimum length of the crest of the stone outlet structure should be 6 feet.

• The baffle board should extend 1 foot into the dike and 4 inches into the ground and be

staked in place.

• The drainage area to this structure should be less than half an acre.
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5.1.5.4.2 ROCK OUTLET PROTECTION

Description

Rock outlet structures are rocks that are placed at the outfall of channels or culverts to reduce the

velocity of flow in the receiving channel to nonerosive rates. 

Applicability

This practice applies where discharge velocities and energies at the outlets of culverts are

sufficient to erode the next downstream reach and it applicable to outlets of all types such as

sediment basins, storm water management ponds, and road culverts. 

Design and Installation Criteria

Hydrologic Design

Hydrologic design consists primarily of selecting the design runoff rate and sizing the outlet

protection. Standard hydrologic calculations should be used to make the calculation, using an

appropriate return period storm for the outlet being protected. Typical return periods range from

2 to 10 years.

Sizing the outlet protection consists of:

• Selecting the Type of Outlet Protection. The outlet protection may consist of a plunge pool

(scour hole), an apron-type arrangement, or an energy dissipation basin (Haan et al., 1994). 

The design of each differs. Plunge pools are typically used for outlet pipes that are elevated

above the water surface. Aprons are used for other types of outlets.

• Selecting the Geometry of the Outlet. Plunge pool geometry is based on the flow rate, pipe

size and slope, tailwater depth, and size of the riprap lining (Haan et al., 1994). Apron

dimensions are determined by the ratio of the tailwater depth to pipe diameter (Haan et al.,

1994). Energy dissipation basins are used as an alternative to the plunge pool. Dimensions

are a function of the brink depth in the pipe at the design flow, pipe diameter, and size of

riprap (Haan et al., 1994).

• Size of Rock Lining. The size of the rock lining is a function of the discharge, pipe size,

tailwater depth, and geometry selected. Details on sizing the rock are given in Haan et al.

(1994).

The design method presented here applies to the sizing of rock riprap and gabions to protect a

downstream area. It does not apply to rock lining of channels or streams. The design of rock

outlet protection depends entirely on the location. Pipe outlets at the top of cuts or on slopes
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steeper than 10 percent cannot be protected by rock aprons or riprap sections due to

reconcentration of flows and high velocities encountered after the flow leaves the apron. 

Installation Criteria

The following criteria should be considered.

• Bottom Grade: The outlet protection apron should be constructed with no slope along its

length. There should be no obstruction at the end of the apron. The elevation of the

downstream end of the apron should be equal to the elevation of the receiving channel or

adjacent ground.

• Alignment: The outer protection apron should be located so that there are no beds in the

horizontal alignment. 

• Materials: The outlet protection may be done using rock riprap, or gabions. Riprap should

be composed of a well-graded mixture of stone sized so that 50 percent of the pieces, by

weight, should be larger than the size determined by using the charts. The minimum d50 size

to be used should be 9 inches. A well-graded mixture is defined as a mixture composed

primarily of larger stone sizes but with a sufficient mixture of other sizes to fill the smaller

voids between the stones. The diameter of the largest stone in such a mixture should be 

2.0 times the size selected in Table 5-22 (MDE, 1994). 

• Thickness: The SHA riprap specification values are summarized in Table 5-22. 

Table 5-22. Riprap Sizes and Thicknesses (SHA Specifications) 

D50 (inches) D100 (inches) Thickness (inches)

Class I 9.5 15 19

Class II 16 24 32

Class III 23 34 46

• Stone Quality: Stone for riprap should consist of field stone or rough and hewn quarry stone. 

The stone should be hard and angular and of a quality that will not disintegrate on exposure

to water or weathering. The specific gravity of the individual stones should be at least 2.5. 

Recycled concrete equivalent may be used provided it has a density of at least 150 pounds

per cubic foot and does not have any exposed steel or reinforcing bars. 

• Filters: A filter is a layer of material placed between the riprap and the underlying soil

surface to prevent soil movement into and through the riprap to prevent piping, reduce uplift

pressure, and collect water. Riprap should have a filter placed under it in all cases. A filter

can be of two general forms: a gravel layer or a geotextile.
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• Gabions: Gabion baskets may be used as rock outlet protection, provided they are made of

hexagonal triple twist mesh with heavily galvanized steel wire. The maximum lined

dimension of the mesh opening should not exceed 4.5 inches. The area of the mesh opening

should not exceed 10 square inches. Gabions should be fabricated in such a manner that the

sides, ends, and lid can be assembled at the construction site into a rectangular basket of the

specified sizes. Gabions should be of a single unit construction and should be installed

according to the manufacturer’s specifications. The area on which the gabion is to be

installed should be graded as shown on the drawings. Foundation conditions should be the

same as for placing rock riprap. Geotextiles should be placed under all gabions. Gabions

must be keyed in to prevent undermining of the main gabion structure.

• The subgrade for the filter, riprap, or gabion should be prepared to the required lines and

grades. Any fill required in the subgrade shall be compacted to a density of approximately

that of the surrounding undisturbed material.

• The rock or gravel should conform to the specified grading limits when installed in the riprap

or filter, respectively.

• Geotextiles should be protected from punching, cutting, or tearing. Any damage other than

occasional small holes should be repaired by placing another piece of geotextile fabric over

the damaged part or by completely replacing the geotextile fabric. All overlaps, whether for

repairs or for joining two pieces of geotextile fabric, should be a minimum of 1 foot in

length. 

• Stone for the riprap or gabion outlets may be placed by equipment. They should be

constructed to the full course thickness in one operation and in such a manner as to avoid

displacement of underlying materials. Care should be taken to ensure that the stone is not

placed so that rolling will cause segregation of stone by size, i.e., the stone for riprap or

gabion outlets should be delivered and placed in a manner that will ensure that it is

reasonably homogeneous with the smaller stones filling the voids between the larger stones. 

Riprap must be placed in a manner to prevent damage to the filter blanket or geotextile

fabric. Hand placement will be required to the extent necessary to prevent damage to the

permanent works.

• Stone should be placed so that it blends in with the existing ground and the depth to the stone

surface is sufficient to transmit the flow without spilling over onto the unprotected surface. 

Effectiveness

There is currently no information on the effectiveness of rock outlet structures. 
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Limitations

Common problems with rock outlet structures include the following:

• Foundation not excavated deep enough or wide enough—restricts the flow cross-section,

resulting in erosion around the apron and sour holes at the outlet.

• Riprap apron should be placed on a suitable foundation to prevent downstream erosion.

• Riprap installed smaller than specified—results in rock displacement; selectively grouting

over the rock materials may stabilize the situation.

• Riprap not extended enough to reach a stable section of the channel—results in downstream

erosion.

• No filter installed under the riprap—results in stone displacement and erosion of the

foundation.

Maintenance

Once a riprap outlet has been installed, the maintenance needs are very low. It should be

inspected after high flows to see if scour has occurred beneath the riprap, if flows have occurred

outside the boundaries of the riprap and caused scour, or if any stones have been dislodged. 

Repairs should be made immediately.

Cost

R. S. Means indicates machine-placed riprap costs of approximately $40 per cubic yard. For a

riprap maximum size between 15 and 24 inches, a cubic yard of riprap will cover between 13.5

and 17 square feet for channel bed (assuming depth of riprap as given in Table 5-22). This

suggests that riprap lining will be between $21 and $27 per square foot of outlet (includes

materials, labor, and equipment, with overhead and profit). R. S. Means (2000) provides a cost

range for gabions ($2.80 to $9 per square foot of coverage) for stone fill depths of 6" to 36",

respectively. These costs include all costs of materials, labor, and installation.

5.1.5.4.3 SUMP PIT

Description

A sump pit is a temporary pit from which pumping is conducted to remove excess water while

minimizing sedimentation. The purpose of the sump pit is to filter water being pumped to

reduce sedimentation to receiving streams.
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Applicability

Sump pits are constructed when water collects and must be pumped away during excavating,

cofferdam dewatering, maintenance or removal of sediment traps and basins, or other uses as

applicable, such as for concrete wash out. 

Design and Installation Criteria

Hydrologic Design

The only hydrologic calculation is determining the expected flow rate and volume to be handled. 

This should follow standard hydrologic computational procedures based on design rainfall,

surface and soil conditions, and the size of the pump.

Installation Criteria and Specifications

The number of sump pits and their locations should be determined by the designer and included

on the plans. Contractors may relocate sump pits to optimize use, but discharge location changes

should be coordinated with inspectors. 

A perforated vertical sandpipe is wrapped with 1⁄2 inch hardware cloth and geotextiles and then

placed in the center of an excavated pit which is then backfilled with filter material consisting of

anything from clean gravel to stone. Water is then pumped from the center of the sandpipe to a

suitable discharge area such as into a sediment trap, sediment basin, or stabilized area. 

A sump pit should conform to the following specifications:

• Pit dimensions are variable, with the minimum diameter being twice the diameter of the

sandpipe.

• The sandpipe should be constructed by perforating a 12- to 36-inch diameter pipe, then

wrapping it with 1⁄2-inch hardware cloth and geotextiles. The perforations should be 1⁄2- x 6-

inch slits or 1-inch diameter holes 6 inches on center.

• The sandpipe should extend 12 to 18 inches above the lip of the pit or riser crest elevation

(basin dewatering), and filter material should extend 3 inches minimum above the anticipated

standing water level. 

Effectiveness

There is currently no information on the effectiveness of the sump pit.
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Limitations

The sump pit must be properly maintained and pumped regularly to avoid clogging. 

Maintenance

To maintain, sump pits must be removed and reconstructed when water can no longer be pumped

out of the sandpipe.

Cost

R. S. Means (2000) provides information appropriate for assessment of a wide range of

dewatering scenarios (i.e., different sump sizes, dewatering durations, and discharge conditions).

In general, installation of earthen sump pits are listed as costing approximately $1.50 per cubic

foot of sump volume. Piping to and away from the sump ranges from $30 to $60 per linear foot.

Pump rentals and operation range between $150 and $500 per day of pumping, depending on the

rate of dewatering. All costs include material, labor, and equipment, with overhead and profit.

5.1.5.4.4 SEDIMENT TANK

Description

A sediment tank is a compartmented tank container through which sediment-laden water is

pumped to trap and retain the sediment. The purpose of a sediment tank is to trap and retain

sediment prior to pumping the water to drainageways, adjoining properties, and rights-of-way

below the sediment tank site. 

Applicability

A sediment tank should be used on sites where excavations are deep and space is limited, such as

urban construction, where direct discharge of sediment-laden water to streams and storm

drainage systems should be avoided. 

Design and Installation Criteria

The location of sediment tanks should facilitate easy cleanout and disposal of the trapped

sediment to minimize interference with construction activities and pedestrian traffic. The tank

size should be determined according to the storage volume of the sediment tank, 1 cubic foot of

storage for each gallon per minute of pump discharge capacity.
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Effectiveness

There is currently no information on the effectiveness of sediment tanks.

Limitations

The sediment tank does not provide any natural infiltration; thus, the trapped sediment and storm 

water must be disposed of properly. 

Maintenance

To properly maintain the sediment tank, it needs to be in a location that is easy to access.

Cost

There is currently no information on the cost of sediment tanks.

5.1.5.4.5 STABILIZED CONSTRUCTION ENTRANCE

Description

The purpose of stabilizing entrances to a construction site is to minimize the amount of sediment

leaving the area as mud attached to motorized vehicles. Installing a pad of gravel over filter

cloth where construction traffic leaves a site can help stabilize a construction entrance. As a

vehicle drives over the gravel pad, mud and other sediments are removed from the vehicle's

wheels (sometimes by washing) and offsite transport of soil is reduced. The gravel pad also

reduces erosion and rutting on the soil beneath the stabilization structure. The fabric reduces the

amount of rutting caused by vehicle tires by spreading the vehicle's weight over a larger soil area

than just the tire width. The filter fabric also separates the gravel from the soil below, preventing

the gravel from being ground into the soil.

Applicability

Typically, stabilized construction entrances are installed at locations where construction traffic

leaves or enters an existing paved road. However, the applicability of site entrance stabilization

should be extended to any roadway or entrance where vehicles will access or leave the site. 

From a public relations point of view, stabilizing construction site entrances can be a worthwhile

exercise. If the site entrance is the most publicly noticeable part of a construction site, stabilized

entrances can improve the appearance to passersby and improve public perception of the

construction project by reducing the amount of mud tracked onto adjacent streets. 
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Design and Installation Considerations

Hydrologic Design

Not applicable.

Installation Criteria and Specifications

All entrances to a site should be stabilized before construction begins and further disturbance of

the site area occurs. The stabilized site entrances should be long enough and wide enough so

that the largest construction vehicle that will enter the site will fit in the entrance with room to

spare. If many vehicles are expected to use an entrance in any one day, the site entrance should

be wide enough for the passage of two vehicles at the same time with room on either side of each

vehicle. For optimum effectiveness, a rock construction entrance should be at least 50 feet long

and at least 10 to 12 feet wide (USEPA, 1992). If a site entrance leads to a paved road, the end

of entrance should be "flared" (made wider as in the shape of a funnel) so that long vehicles do

not go off the stabilized area when turning onto or off of the paved roadway. 

If a construction site entrance crosses a stream, swale, roadside channel, or other depression, a

bridge or culvert should be provided to prevent erosion from unprotected banks.

Stone and gravel used to stabilize the construction site entrance should be large enough so that

they are not carried off-site with vehicle traffic. In addition, sharp-edged stone should be

avoided to reduce the possibility of puncturing vehicle tires. Stone or gravel should be installed

at a depth of at least 6 inches for the entire length and width of the stabilized construction

entrance. 

Effectiveness

Stabilizing construction entrances to prevent sediment transport off-site is effective only if all

entrances to the site are stabilized and maintained. Also, stabilization of construction site

entrances may not be very effective unless a wash rack is installed and routinely used (Corish,

1995) but this can be problematic for sites with multiple entrances with high vehicle traffic. 

Limitations

Although stabilizing a construction entrance is a good way to help reduce the amount of

sediment leaving a site, some soil may still be deposited from vehicle tires onto paved surfaces. 

To further reduce the chance that these sediments will pollute storm water runoff, sweeping of

the paved area adjacent to the stabilized site entrance is recommended.

For sites using wash stations, a reliable water source to wash vehicles before leaving the site

might not be initially available. In this case, water may have to be trucked to the site at
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additional cost. Discharge from the wash station should be directed into an appropriate sediment

control structure. 

Maintenance

Stabilization of site entrances should be maintained until the remainder of the construction site

has been fully stabilized. Stone and gravel might need to be periodically added to each

stabilized construction site entrance to keep the entrance effective. Soil that is tracked offsite

should be swept up immediately for proper disposal.

For sites with wash racks at each site entrance, sediment traps will have to be constructed and

maintained for the life of the project. Maintenance will entail the periodic removal of sediment

from the traps to ensure their continued effectiveness. 

Cost

Without a wash rack, construction site entrance stabilization costs range from $1,000 to $4,000. 

On average, the initial construction cost is around $2,000 per entrance. When maintenance costs

are included, the average total annual cost for a 2-year period, is approximately $1,500. 

If a wash rack is included in the construction site entrance stabilization, the initial construction

costs range from $1,000 to $5,000, with an average initial cost of $3,000 per entrance. Total

annual cost, including maintenance for an estimated 2-year life span, is approximately $2,200

per year (USEPA, 1993).

5.1.5.4.6 LAND GRADING

Description

Land grading involves reshaping the ground surface to planned grades as determined by an

engineering survey, evaluation, and layout. Land grading provides more suitable topography for

buildings, facilities, and other land uses and helps to control surface runoff, soil erosion, and

sedimentation both during and after construction.

Applicability

Land grading is applicable to sites with steep topography or easily erodible soils because it

stabilizes slopes and decreases runoff velocity. Grading activities should maintain existing

drainage patterns as much as possible. 
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Design and Installation Criteria

Before grading activities begin, decisions should be made regarding the steepness of cut-and-fill

slopes and how the slopes will be protected from runoff, stabilized, and maintained. A grading

plan that establishes which areas of the site will be graded, how drainage patterns will be

directed, and how runoff velocities will affect receiving waters should be prepared. The grading

plan also includes information regarding when earthwork will start and stop, establishes the

degree and length of finished slopes, and dictates where and how excess material will be

disposed of (or where borrow materials will be obtained if needed). Berms, diversions, and

other storm water practices that require excavation and filling should also be incorporated into

the grading plan.

A low-impact development BMP that can be incorporated into a grading plan is site

fingerprinting, which involves clearing and grading only those areas necessary for building

activities and equipment traffic. Adhering to strict limits of clearing and grading helps to

maintain undisturbed temporary or permanent buffer zones in the grading operation and provides

a low-cost sediment control measure that will help reduce runoff and off-site sedimentation. The

lowest elevation of the site should remain undisturbed to provide a protected storm water outlet

before storm drains or other construction outlets are installed.

Effectiveness

Land grading is an effective means of reducing steep slopes and stabilizing highly erodible soils

when implemented with storm water management and erosion and sediment control practices in

mind. Land grading is not effective when drainage patterns are altered or when vegetated areas

on the perimeter of the site are destroyed. 

Limitations

Construction sites are routinely graded to prepare a site for buildings and other structures. 

Improper grading practices that disrupt natural storm water patterns might lead to poor drainage,

high runoff velocities, and increased peak flows during storm events. Clearing and grading of

the entire site without vegetated buffers promotes off-site transport of sediments and other

pollutants. Grading plans should be designed with erosion and sediment control and storm water

management goals in mind; grading crews should be carefully supervised to ensure that the plan

is implemented as intended. 
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Maintenance

All graded areas and supporting erosion and sediment control practices should be periodically

checked, especially after heavy rainfalls. All sediment should be promptly removed from

diversions or other storm water conveyances. If washouts or breaks occur, they should be

repaired immediately. Prompt maintenance of small-scale eroded areas is essential to prevent

these areas from becoming significant gullies. 

Cost

Land grading is practiced at virtually all construction sites—additional site planning to

incorporate storm water and erosion and sediment controls in grading plans can require several

hours of planning by a certified engineer or landscape architect. Extra time might be required to

excavate diversions and construct berms, and fill materials might be needed to build up lowlying areas or fill depressions. 

Where grading is performed to manage on-site storm water, R. S. Means (2000) suggests the

cost of fine grading, soil treatment, and grassing to be approximately $2 per square yard of earth

surface area. Shallow excavation/trenching (1 to 4 feet deep) with a backhoe in areas not

requiring dewatering can be performed for $4 to $5 per cubic yard of removed material. Larger

scale grading requires a site-specific assessment of an alternative grading apparatus and a

detailed fill/excavation material balance to retain as much soil on site as possible.

5.1.5.4.7 TEMPORARY ACCESS WATERWAY CROSSING

Description

A temporary stream crossing is a structure erected to provide a safe and stable way for

construction vehicle traffic to cross a running watercourse. The primary purpose of such a

structure is to provide streambank stabilization, to reduce the risk of damaging the streambed or

channel, and to reduce the risk of sediment loading from construction traffic. A temporary

stream crossing may be a bridge, culvert, or ford.

Applicability

Temporary stream crossings are applicable wherever heavy construction equipment must be

moved from one side of a stream channel to the other or where lighter construction vehicles will

cross the stream a number of times during the construction period. In either case, an appropriate

method for ensuring the stability of the streambanks and preventing large-scale erosion is

necessary.

A bridge or culvert is the best choice for most temporary stream crossings. If properly designed,

each can support heavy loads, and materials used to construct most bridges and culverts can be
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salvaged after they are removed. Fords are appropriate in steep areas subject to flash flooding,

where normal flow is shallow or intermittent across a wide channel. Fords should be used only

where stream crossings are expected to be infrequent. 

Design and Installation Criteria

Because of the potential for stream degradation, flooding, and safety hazards, stream crossings

should be avoided on a construction site whenever possible. Consideration should be given to

alternative site access routes before arrangements are made to erect a temporary stream crossing. 

If it is determined that a stream crossing is necessary, an area where the potential for erosion is

low should be selected. The stream crossing structure should be selected during a dry period if

possible to reduce sediment transport into the stream.

If needed, over-stream bridges are generally the preferred temporary stream crossing structure. 

The expected load and frequency of the stream crossing, however, will govern the selection of a

bridge as the correct choice for a temporary stream crossing. These types of temporary bridges

usually cause minimal disturbance to a stream's banks and cause the least obstruction to stream

flow and fish migration. They should be constructed only under the supervision and approval of

a qualified engineer.

As general guidelines for constructing temporary bridges, clearing and excavation of the stream

shores and bed should be kept to a minimum. Sufficient clearance should be provided for

floating objects to pass under the bridge. Abutments should be parallel to the stream and on

stable banks. If the stream is less than 8 feet wide at the point where a crossing is needed, no

additional in-stream supports should be used. If the crossing is to extend across a channel wider

than 8 feet (as measured from top of bank to top of bank), the bridge should be designed with

one in-water support for each 8 feet of stream width. 

A temporary bridge should be anchored by steel cable or chain on one side only to a stable

structure on shore. Examples of anchoring structures include trees with a large diameter, large

boulders, and steel anchors. By anchoring the bridge on one side only, there is a decreased risk

of causing a downstream blockage or flow diversion if a bridge is washed out.

When constructing a culvert, filter cloth should be used to cover the streambed and streambanks

to reduce settlement and improve the stability of the culvert structure. The filter cloth should

extend a minimum of 6 inches and a maximum of 1 foot beyond the end of the culvert and

bedding material. The culvert piping should not exceed 40 feet in length and should be of

sufficient diameter to allow for complete passage of flow during peak flow periods. The culvert

pipes should be covered with a minimum of 1 foot of aggregate. If multiple culverts are used, at

least 1 foot of aggregate should separate the pipes.

Fords should be constructed of stabilizing material such as large rocks.
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Effectiveness

Both temporary bridges and culverts provide an adequate path for construction traffic crossing a

stream or watercourse. 

Limitations

Bridges can be considered the greatest safety hazard of all temporary stream crossing structures

if not properly designed and constructed. Bridges might also prove to be more costly in terms of

repair costs and lost construction time if they wash out or collapse (Smolen et al., 1988). 

The construction and removal of culverts are usually very disturbing to the surrounding area, and

erosion and downstream movement of soils are often great. Culverts can also create obstructions

to flow in a stream and inhibit fish migration. Depending on their size, culverts can be blocked

by large debris in a stream and are therefore vulnerable to frequent blockage and washout.

If given a choice between building a bridge or a culvert as a temporary stream crossing, a bridge

is preferred because of the relative minimal disturbance to streambanks and the opportunity for

unimpeded flow through the channel. The approaches to fords often have high erosion potential. 

In addition, excavation of the streambed and approach to lay riprap or other stabilization material

causes major stream disturbance. Mud and other debris are transported directly into the stream

unless the crossing is used only during periods of low flow.

Maintenance

Temporary stream crossings should be inspected at least once a week and after all significant

rainfall events. If any structural damage is reported to a bridge or culvert, construction traffic

should stop using the structure until appropriate repairs are made. Evidence of streambank

erosion should be repaired immediately.

Fords should be inspected closely after major storm events to ensure that stabilization materials

remain in place. If the material has moved downstream during periods of peak flow, the lost

material should be replaced immediately.

Cost

In general, temporary bridges are more expensive to design and construct than culverts. Bridges

are also associated with higher maintenance and repair costs should they fail. Additional costs

may accrue to the site team in terms of lost construction time if a temporary structure is washed

out or otherwise fails.

Temporary bridging costs range as a function of the width of the bridge span and the duration of

application. If the bridging is permanent, a mean cost of $50 per square foot for an 8-foot wide
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steel arch bridge (no foundation costs included) can be used for conceptual cost estimation 

(R. S. Means, 2000). If rental bridging is employed, then rates are probably on the order of 20 to

50 percent of the bridge (permanent) cost, but will range based on the rental duration and

mobilization distance.

5.1.5.4.8 DUST CONTROL

General Description

Dust control measures are practices that help reduce ground surface and air movement of dust

from disturbed soil surfaces. Construction sites are good candidates for dust control measures

because land disturbance from clearing and excavation generates a large amount of soil

disturbance and open space for wind to pick up dust particles. To illustrate this point, research at

construction sites has established an average dust emission rate of 1.2 tons/acre/month for active

construction (WA Dept. of Ecology, 1992). These airborne particles pose a dual threat to the

environment and human health. First, dust can be carried off-site, thereby increasing soil loss

from the construction area and increasing the likelihood of sedimentation and water pollution. 

Second, blowing dust particles can contribute to respiratory health problems and create an

inhospitable working environment. 

Applicability

Dust control measures are applicable to any construction site where dust is created and there is

the potential for air and water pollution from dust traveling across the landscape or through the

air. Dust control measures are particularly important in arid or semiarid regions where soil can

become extremely dry and vulnerable to transport by high winds. 

Also, dust control measures should be implemented on all construction sites where there will be

major soil disturbances or heavy construction activity, such as clearing, excavation, demolition,

or excessive vehicle traffic. Earthmoving activities are the major source of dust from

construction sites, but traffic and general disturbances can also be major contributors (WA Dept.

of Ecology, 1992).

The specific dust control measures implemented at a site will depend on the topography, land

cover, soil characteristics and amount of rainfall at the site.

Design and Installation Criteria

When designing a dust control plan for a site, the amount of soil exposed will dictate the

quantity of dust generation and transport. Therefore, construction sequencing and disturbing

small areas at one time can greatly reduce problematic dust from a site. If land must be

disturbed, additional temporary stabilization measures should be considered prior to disturbance.
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A number of methods can be used to control dust from a site. The following is a brief list of

control measures and their design criteria. Not all control measures will be applicable to a given

site. The owner, operator, and contractors responsible for dust control at a site should determine

which practices accommodate their needs based on specific site and weather conditions. 

Sprinkling/Irrigation: Sprinkling the ground surface with water until it is moist is an effective

dust control method for haul roads and other traffic routes (Smolen et al., 1988). This

practice can be applied to almost any site.

Vegetative Cover: In areas not expected to handle vehicle traffic, vegetative stabilization of

disturbed soil is often desirable. Vegetative cover provides protection to surface soils and

slows wind velocity at the ground surface, thus reducing the potential for dust to become

airborne.

Mulch: Mulching can be a quick and effective means of dust control for a recently disturbed

area (Smolen et al., 1988).

Wind Breaks: Wind breaks are barriers (either natural or constructed) that reduce wind velocity

through a site and therefore reduce the possibility of picking up suspended particles. Wind

breaks can be trees or shrubs left in place during site clearing or constructed barriers such as

a wind fence, snow fence, tarp curtain, hay bale, crate wall, or sediment wall (USEPA,

1992).

Tillage: Deep tillage in large open areas brings soil clods to the surface where they rest on top of

dust, preventing it from becoming airborne.

Stone: Stone can be an effective dust deterrent for construction roads and entrances.

Spray-on Chemical Soil Treatments (palliatives): Examples of chemical adhesives include

anionic asphalt emulsion, latex emulsion, resin-water emulsions, and calcium chloride. 

Chemical palliatives should be used only on mineral soils. When considering chemical

application to suppress dust, consideration should be taken as to whether the chemical is

biodegradable or water-soluble and what effect its application could have on the surrounding

environment, including waterbodies and wildlife.
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Table 5-23 shows application rates for some common spray-on adhesives as recommended by

Smolen et al. (1988). 

Table 5-23. Application Rates for Spray-On Adhesives

Spray on Adhesive Water Dilution Type of Nozzle Application (gal/acre)

Anionic Asphalt Emulsion 7:1 Coarse spray 1,200

Latex Emulsion 12.5:1 Fine spray 235

Resin in Water 4:1 Fine spray 300

Source: Smolen et al., 1988.

Effectiveness

Sprinkling/Irrigation: Not available.

Vegetative Cover: Not available.

Mulch: Can reduce wind erosion by 80 percent.

Wind Breaks/Barriers: For each foot of vertical height, an 8- to 10-foot deposition zone develops

on the leeward side of the barrier. The barrier density and spacing will change its

effectiveness at capturing windborne sediment.

Tillage: Roughening the soil can reduce soil losses by approximately 80 percent.

Stone: The sizes of the stone can affect the amount of erosion that will take place. In areas of

high wind, small stones are not as effective as a 20 cm stone.

Spray-on Chemical Soil Treatments (palliatives): Effectiveness of polymer stabilization

methods ranges from 70 percent to 90 percent.

Limitations

In areas where evaporation rates are high, water application to exposed soils may require near

constant attention. If water is applied in excess, runoff may result from the site and possibly

create conditions where vehicles could track mud onto public roads. 

Chemical applications should be used sparingly and only on mineral soils (not high organic

content soils) because their misuse can create additional surface water pollution from runoff or

contaminate groundwater. Chemical applications might also present a health risk if excessive

amounts are used.
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Maintenance

Because dust controls are dependent on specific site conditions, including the weather,

inspection and maintenance are unique for each site. Generally, however, dust control measures

involving application of either water or chemicals require more monitoring than structural or

vegetative controls to remain effective. If structural controls are used, they should be inspected

for deterioration on a regular basis to ensure they are still achieving their intended purpose.

Cost

Chemical dust control measures can vary widely in cost depending on specific needs of the site

and level of dust control desired. One manufacturer of a chloride product estimated a cost of 

$1,089 per acre for application to road surfaces, but cautioned that cost estimates without a

specific site evaluation are rather inaccurate. 

5.1.5.4.9 STORM DRAIN INLET PROTECTION

Description

Storm drain inlet protection measures are controls that help prevent soil and debris from on-site

erosion from entering storm drain drop inlets. Typically, these measures are temporary controls

that are implemented prior to large-scale disturbance of the surrounding site. These controls are

advantageous because their implementation allows storm drains to be used during even the early

stages of construction activities. The early use of storm drains during project development

significantly reduces the occurrence of future erosion problems (Smolen et al., 1988). 

Three temporary control measures to protect storm drain drop inlets are

• Excavation around the perimeter of the drop inlet

• Fabric barriers around inlet entrances

• Block and gravel protection

Excavation around a storm drain inlet creates a settling pool to remove sediments. Weep holes

protected by gravel are used to drain the shallow pool of water that accumulates around the inlet. 

A fabric barrier made of porous material erected around an inlet can create an effective shield to

sediment while allowing water to flow into the storm drain. This type of barrier can slow runoff

velocity while catching soil and other debris at the drain inlet. Block and gravel inlet protection

uses standard concrete blocks and gravel to form a barrier to sediments while permitting water

runoff through select blocks that are laid sideways. 
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In addition to the materials listed above, limited temporary storm water drop inlet protection can

also be achieved with the use of straw bales or sandbags to create barriers to sediment. 

For permanent storm drain drop inlet protection after the surrounding area has been stabilized,

sod can be installed as a barrier to slow storm water entry to storm drain inlets and capture

sediments from erosion. This final inlet protection measure can be used as an aesthetically

pleasing way to slow storm water velocity near drop inlet entrances and remove sediments and

other pollutants from runoff.

A new technology that uses an insert trap into the inlet itself has been developed (Adams et al.,

2000). This technique showed good results on initial tests, trapping more than 50 percent of the

incoming sediment in flows typical of those into urban storm drains. This technique is being

further developed with a pending patent application.

 

Applicability

All temporary controls should have a drainage area no greater than 1 acre per inlet. It is also

important for temporary controls to be constructed prior to disturbance of the surrounding

landscape. Excavated drop inlet protection and block and gravel inlet protection are applicable

to areas of high flow where overflow is anticipated into the storm drain. Fabric barriers are

recommended for smaller, relatively flat drainage areas (slopes less than 5 percent leading to the

storm drain).

Temporary drop inlet control measures are often used in combination with each other and with

other storm water control techniques.

Design and Installation Considerations

Hydrologic Design

Hydrologic computations are not necessary with present technologies. A specified limitation of

1 acre per inlet limits flow rates, dependent on local rainfall and runoff considerations.

Installation Criteria and Specifications

The following criteria should be followed until future research establishes better techniques:

• With the exception of sod drop inlet protection, these controls should be installed before any

soil disturbance in the drainage area. 

• Excavation around drop inlets should be dug a minimum of 1 foot deep (2 feet maximum)

with a minimum excavated volume of 35 cubic yards per acre disturbed. Side slopes leading

to the inlet should be no steeper than 2:1. The shape of the excavated area should be
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designed such that the dimensions fit the area from which storm water is anticipated to drain. 

For example, the longest side of an excavated area should be along the side of the inlet

expected to drain the largest area. 

• Fabric inlet protection is essentially a filter fence placed around the inlet. The fabric asures

should not be used as stand-alone sediment control measures. To increase inlet protection

effectiveness, these practices should be used in combination with other measures, such as

small impoundments or sediment traps (USEPA, 1992). Temporary storm drain inlet

protection is not intended for use in drainage areas larger than 1 acre. Generally, storm water

inlet protection measures are practical for relatively low sediment and low volume flows.

Frequent maintenance of storm drain controls is necessary to prevent clogging. If sediment and

other debris clog the water intake, drop intake control measures can actually cause erosion in

unprotected areas. 

Maintenance

All temporary control measures must be checked after each storm event. To maintain the

sediment capacity of the shallow settling pools created from these techniques, accumulated

sediment should be removed from the area around the drop inlet (excavated area, around fabric

barrier, or around block structure) when the sediment storage is reduced by approximately 50

percent. Additional debris should be removed from the shallow pools on a periodic basis.

Weep holes in excavated areas around inlets can become clogged and prevent water from

draining from the shallow pools that form. Should this happen, unclogging the water intake may

be difficult and costly. 

Cost 

The cost of implementing storm drain drop inlet protection measures will vary depending on the

control measure chosen. Generally, initial installation costs range from $50 to $150 per inlet,

with an average cost of $100 (USEPA, 1993). Maintenance costs can be high (annually, up to

100 percent of the initial construction cost) because of frequent inspection and repair needs. The

Southeastern Wisconsin Regional Planning Commission has estimated that the cost of

installation of inlet protection devices ranges from $106 to $154 per inlet (SEWRPC, 1991). 

5.1.5.4.10 POLYACRYLAMIDE (PAM)

General Description

The term polyacrylamide (PAM) is a generic term that refers to a broad class of compounds. 

There are hundreds of specific PAM formulations, and all have unique properties that depend on

polymer chain length and number and kinds of functional group substitutions along the chain. 
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PAMs are classified according to their molecular weight and ionic charge and are available in

solid, granular, liquid, or emulsion forms.

PAM’s effectiveness to prevent or reduce erosion is due to its affinity for soil particles, largely

via coulombic and Van der Waals attraction. These surface attractions enhance particle

cohesion, stabilizing soil structure against shear-induced detachment and transport in runoff. In

a soil application, PAM aggregates soil particles, increasing pore space and infiltration capacity,

resulting in reduced runoff. These larger particle aggregates are less susceptible to raindrop and

scour erosion, thus reducing the potential to mobilize sediments. 

Applicability

Because of ease in application, PAM is well suited as a short-term erosion prevention BMP,

especially for areas with limited access or steep slopes that hinder personnel from applying other

cover materials. PAM can be used to augment other cover practice BMPs, though it can be

effective when applied alone. Thus, the ease of application, low maintenance, and relatively low

cost associated with PAM make it a practical solution to soil stabilization during construction. 

Application Criteria

PAM can be applied to soil through either a dry granular powder or a liquid spray form. Optimal

application rates to prevent erosion on construction sites are generally less than 1 kg/ha (about 1

lb/ac) (Tobiason et al., 2000). However, the concentration required can vary for specific soil

properties and construction phases. WDOT (2002) suggests a dosage of 60 mg/L for roadway

erosion and sediment control. This is higher than the rate recommended by the University of

Nebraska for an agricultural application (10 parts per million). To put this into context, one half

pound of PAM in1000 gallons of water results in a PAM concentration of 60 mg/L, which treats

1 acre of exposed soil to WDOT recommendations. 

Effectiveness

A study performed in Dane County, Wisconsin, analyzed 15 small plots (1 meter x 1 meter) for

runoff and sediment yield on a construction site. The study concluded that when a solution of

PAM-mix with mulch/seeding was applied to dry soil and compared with the control (no PAMmix application to dry soil), an average reduction of 93 percent in sediment yield was found. An

average reduction of 77 percent in sediment yield was the worst performing PAM treatment and

occurred when PAM-mix in solution was applied to moist soil. The application of dry PAM-mix

to dry soil reduced sediment by 83 percent and decreased runoff by 16 percent when compared

to the control. The results show that regardless of the application method, PAM-mix was

effective in reducing sediment yield in the test plots (Roa-Espinosa et al., 2000). 
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A second study performed in Washington analyzed the runoff from three different construction

sites: an erosion control test facility, a highway construction site, and an airport runway. Table

5-24 summarizes the 225 samples analyzed in Tobiason et al. (2000).

Table 5-24. Turbidity Reduction Values from PAM

Volume, m3 Turbidity Reduction (%)

Maximum 350 99.97

Median 285 97.6

Minimum 133 46

Limitations

Currently PAMs are most commonly produced as dry granules. They completely dissolve and

remain dissolved if mixed properly. If added too quickly or if not stirred vigorously the granules

rapidly form nondissolvable gels on contact with water or collect in low turbulence areas as

syrupy concentrations that dissolve slowly in an uncontrolled pattern over a period of hours or

days (USDA, 1994). 

 

In addition, when spilled on hard surfaces, PAM solutions are extremely slippery and hazardous

to foot and vehicle traffic. PAM dust is highly hygroscopic and, if inhaled, could impair

breathing. Certain neutral and cationic PAMs at very high exposure levels produce irritation in

humans and are somewhat toxic to certain aquatic organisms; therefore, PAM should be used in

strict compliance with state and federal label requirements. 

Finally, although PAM is rather inexpensive, there are considerable infrastructure needs and

operating costs; thus, sophisticated onsite polymer treatment systems may not be appropriate for

certain projects.

Cost 

The cost of PAM ranges from $1.25 per pound to $5.00 per pound (Entry et al., 1999). The cost

of PAM application depends on the system employed. PAM can be used in a centralized

treatment system (e.g., at a sedimentation basin) to treat larger areas, or dispersed in granular or

liquid form. In Tobiason et al. (2000), the startup costs for the batch treatment system amounted

to $90,000. Monthly expenses averaged $18,000 for operations and maintenance and $13,000

for materials and equipment. The total costs for this phase totaled about $245,000, less than 1

percent of total construction costs. If dispersed through irrigation systems (for agriculture), the

seasonal cost of PAM treatment is $9 to $15 per acre (Kay-Shoemake, et. al., 2000), where a

season probably requires between 5 and 10 applications. 

For construction sites, it is more likely that PAM would be applied as an additive to the

hydroseed mix and applied when final grade is established and cover vegetation is installed.
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Based on a recent scan of the Internet, there are numerous suppliers who provide PAM as a low

cost additive for hydroseeding, suggesting PAM application costs can be incorporated into that

of hydroseeding ($540 to $700 per acre depending on which seed is applied). An additional cost

would be incurred to sample site soils to customize the dosage and delivery mechanisms for

individual sites. In addition, re-application of PAM in granular or liquid form to areas with rill

development (poor vegetation cover) would require additional funds. Where re-application of

granular PAM is used, R. S. Means (2000) suggests a cost of approximately $5 per 1000 square

feet for spreading soil admixtures by hand.
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5.1.6 SUMMARY

The BMP information presented in sub-section 5.1 is summarized in Tables 5-25 through 5-28. 

Table 5-25. Summary of Information on Erosion Control and Prevention BMPs

(Sub-section 5.1.5.1)

BMP Type Physical Impact Mitigation Other Impacts

Receiving Water Quality Downstream Impacts

Planning/

Staging/

Scheduling

Could be low cost.

One data set shows 42% reduction

in sediment yield due to

planning/staging/scheduling.

Requires additional advance

planning and management.

Impact could be evaluated with

models as well as

experimentally since several

computer models are

available.

Could be low cost.

Database is poor.

No validated urban runoff models

available for theoretical

analysis of downstream

impacts.

Potential exists to modify existing

models to make the analysis

of downstream impacts on

geomorphology.

No good cause-effect

relationships

available.

Other impacts not

evaluated. 

Vegetative

Stabilization

Could be low cost

Can be very effective in some

cases with advance planning.

Can be important on streambanks.

Limited applicability in the active

construction area.

Complements other practices. 

Practice is seasonably dependent

in most of nation.

Impact could be evaluated with

models as well as

experimentally since several

computer models are

available.

Could be low cost.

Database is poor.

No validated urban runoff models

available for theoretical

analysis of downstream

impacts.

Potential exists to modify existing

models to make the analysis

of downstream impacts on

geomorphology.

No good cause-effect

relationships

available.

Other impacts not

evaluated.

Grass Lined

Channels

Long history of use in channels

draining disturbed areas.

Well established procedures for

design and extensive database

on stable designs under

widely varied conditions. 

Some procedures are available,

with limited validation, to

obtain a first estimate of

sediment trapping by grasslined channels.

Limited database on trapping of

sediment.

Database is poor.

No validated urban runoff models

available for theoretical

analysis of downstream

impacts.

Some potential exists to modify

existing models to make the

analysis of downstream

impacts on geomorphology.

No good cause-effect

relationships

available.

Database shows wide

variations in

effectiveness in

trapping

chemicals.

Other impacts not

evaluated.
Development Document for Construction and Development Proposed Effluent Guidelines

Table 5-25. Summary of Information on Erosion Control and Prevention BMPs

(Sub-section 5.1.5.1)

BMP Type Physical Impact Mitigation Other Impacts

Receiving Water Quality Downstream Impacts

June 2002 5-113

Seeding Low-cost method for establishing

vegetation. 

Occurs near the end of active

construction.

Requires significant time for

establishment.

Need a prepared seedbed.

Good database on impact on soil

erosion.

Should be supported by other

BMPs.

Should not be evaluated as standalone practice, but as part of a

system.

Database is poor.

No validated urban runoff models

available for theoretical

analysis of downstream

impacts.

Some potential exists to modify

existing models to make the

analysis of downstream

impacts on geomorphology.

No good cause-effect

relationships available.

Other impacts not

evaluated.

Sodding High-cost method of establishing

vegetation.

Immediate stabilization.

Requires significant management

attention during

establishment.

Good database on impact on soil

erosion.

Very effective way of controlling

erosion.

Works well for grass waterways

and other significant problems

area.

Should be supported by other

BMPs.

Should not be evaluated as standalone practice, but as part of a

system.

Database is poor.

No validated urban runoff models

available for theoretical

analysis of downstream

impacts.

Some potential exists to modify

existing models to make the

analysis of downstream

impacts on geomorphology.

No good cause-effect

relationships

available.

Other impacts not

evaluated.

Mulching Relatively low-cost method of

providing cover.

Can be highly effective in

reducing soil loss when

properly anchored. 

Good database on impact on soil

erosion.

Variety of materials can be used.

Installation is rapid. 

Not a stand-alone practice.

Due to interference with

construction operations, the

times that it can be used

during active construction are

limited. 

Database is poor.

No validated urban runoff models

available for theoretical

analysis of downstream

impacts.

Some potential exists to modify

existing models to make the

analysis of downstream

impacts on geomorphology.

No good cause-effect

relationships

available.

Other impacts not

evaluated.
Development Document for Construction and Development Proposed Effluent Guidelines

Table 5-25. Summary of Information on Erosion Control and Prevention BMPs

(Sub-section 5.1.5.1)

BMP Type Physical Impact Mitigation Other Impacts

Receiving Water Quality Downstream Impacts

June 2002 5-114

Erosion

Control

Matting

/Geotextiles

Cost is highly variable.

Effectiveness in controlling

sediment is variable

depending on type material.

Can provide immediate protection

to exposed soils.

Not a stand-alone practice.

Due to interference with

construction operations, the

times that it can be used

during active construction are

limited.

Disposal is a significant problem

and may require landfilling.

Can be used for channel linings as

stand alone or under riprap.

Fair database on effectiveness in

preventing erosion.

Database is poor.

No validated urban runoff models

available for theoretical

analysis of downstream

impacts.

Some potential exists to modify

existing models to make the

analysis of downstream

impacts on geomorphology

No good cause-effect

relationships

available.

Other impacts not

evaluated.

Vegetative

Buffer

Strips

Can be highly effective in trapping

sediment.

Effectiveness is well established

and considerable data

collected.

Well-validated models are

available to predict the

impacts of constructed filter

strips on sediment trapping.

Models are included in watershed

stormwater and sediment

models.

Modifications needed for natural

riparian zones. 

Require routine maintenance.

May be most appropriate where

sediment loads are relatively

low. 

Database is poor.

No validated urban runoff models

available for theoretical

analysis of downstream

impacts.

Some potential exists to modify

existing models to make the

analysis of downstream

impacts on geomorphology

No good cause-effect

relationships

available.

Other impacts not

evaluated.
Development Document for Construction and Development Proposed Effluent Guidelines

Table 5-25. Summary of Information on Erosion Control and Prevention BMPs

(Sub-section 5.1.5.1)

BMP Type Physical Impact Mitigation Other Impacts

Receiving Water Quality Downstream Impacts

June 2002 5-115

Topsoiling Important in vegetative

establishment.

No protection until cover is

established. 

Not a stand-alone practice, but

must be supported by other

BMPs.

No known information to describe

effectiveness and cost not

currently available.

Database is poor.

No validated urban runoff models

available for theoretical

analysis of downstream

impacts.

Some potential exists to modify

existing models to make the

analysis of downstream

impacts on geomorphology

No good cause-effect

relationships

available.

Other impacts not

evaluated.
Development Document for Construction and Development Proposed Effluent Guidelines

June 2002 5-116

Table 5-26. Summary of Information on Erosion Control and Prevention BMPs 

(Sub-section 5.1.5.2)

BMP Type

Physical Impact Mitigation

Receiving Water Quality Downstream Impacts Other Impacts

Earth Dike • Used to protect down slope areas.

• Should be stabilized prior to use.

• Requires maintenance after every

major storm.

• Can be significant source of

sediment if not properly

constructed.

• Little data available on its

effectiveness as a BMP.

• Can be relatively inexpensive,

depending on design.

• Not a stand-alone procedure.

No known information available. No known information

available.

Temporary

Swale

• Effectively a grass-lined drainage

ditch with shallow side slopes.

• Can be applied in many areas, but

use limited in arid areas.

• Contaminants that will harm

vegetation, such as oils and

greases, cannot be discharged to

the system.

• Continuous water flow cannot be

tolerated by the grass lining.

• Effectiveness depends on

infiltration. Can be a problem of

groundwater pollution with high

water tables.

• Some studies show that they export

bacteria.

• Some studies show high removal

efficiency for TSS, fair for

nutrients, are variable for metals.

• No general relationships available

to predict the impact under widely

varied climates and conditions,

hence the effectiveness cannot be

predicted for a given situation

beyond the limited database.

No known information available. No known information

available.
Development Document for Construction and Development Proposed Effluent Guidelines

Table 5-26. Summary of Information on Erosion Control and Prevention BMPs 

(Sub-section 5.1.5.2)

BMP Type

Physical Impact Mitigation

Receiving Water Quality Downstream Impacts Other Impacts

June 2002 5-117

Temporary

Storm Drain

Diversion

(Pipe)

• Reroutes existing drainage systems. 

Primary benefit is to separate

drainage water originating from

undisturbed and construction and

reduce the volume of water to be

treated. 

• Can be combined with other

structures, such as sediment traps,

and used for sediment trapping.

• Require little maintenance.

• Requires outlet stabilization. Can

be a significant source of sediment

without outlet stabilization.

• Can be costly, depending on size,

installation, and removal.

No known information available. No known information

available.

Pipe Slope

Drain

• Routes runoff from concentrated

flow to stabilized areas.

• Can be very effective in

eliminating gully erosion problems,

if properly installed and

maintained.

• Can be constructed from low-cost

corrugated PVC, but must be

anchored or buried along slope.

• Needs to be checked frequently for

sedimentation and other

maintenance problems.

No known information available. No known information

available.

Stone Check

Dams

• Reduces velocity of flow and

prevents erosion.

• Stabilizes channel slope on steep

sections by stairstepping.

• Can trap small percentages of

sediment behind dam.

• Used for short periods of time

where channel lining is impractical.

• Limited lab studies show high

effectiveness, but very limited field

studies show low trapping

efficiency. 

• Must be installed such that

overtopping occurs over the rock

fill and not around the perimeter. 

• Should not be used in continuously

flowing streams.

• Relatively expensive, if properly

installed.

• Procedures for predicting impact of

properly installed stone check dams

are available and incorporated into

watershed computer models.

No known information available. No known information

available.
Development Document for Construction and Development Proposed Effluent Guidelines

Table 5-26. Summary of Information on Erosion Control and Prevention BMPs 

(Sub-section 5.1.5.2)

BMP Type

Physical Impact Mitigation

Receiving Water Quality Downstream Impacts Other Impacts

June 2002 5-118

Lined

Waterways

• Designed for stability and capacity.

• Local rainfall-runoff conditions

and linings will influence channel

dimensions.

• Require some maintenance during

vegetative establishment.

• Not designed as sediment removal

device, but to prevent channel

erosion.

No known information available. No known information

available.
Development Document for Construction and Development Proposed Effluent Guidelines

June 2002 5-119

Table 5-27. Summary of Information on Erosion Control and Prevention BMPs

(Sub-section 5.1.5.3)

BMP Type Physical Impact Mitigation Other Impacts

Receiving Water Quality Downstream Impacts

Silt Fence Most widely recognized sediment

control BMP.

Frequently poorly installed with little

design consideration.

Maintenance is frequently poor,

resulting in frequent failure. 

Frequent maintenance is required

for proper operation.

Laboratory studies show fair to good

sediment trapping by filter fence,

but limited field studies do not

show the same results.

Evaluations of installations show that

failure is frequent, coming from

undercutting of the fabric and

subsequent gully erosion. 

Should not be installed where rocks and

other hard surfaces prevent

anchoring. 

No validated procedures are available

to predict the effectiveness of the

filter fence in trapping sediment,

primarily because of the lack of

validated relationships for

predicting flow through the filter

fence.

Procedures for evaluating the

anchoring requirements and

support post requirements have not

adequately accounted for variable

soil strength conditions, resulting

in frequent failure of the fence

under loading. 

Database is poor.

No validated urban runoff models

available for theoretical analysis

of downstream impacts.

Some potential exists to modify

existing models to make the

analysis of downstream impacts on

geomorphology

No good cause-effect

relationships

available.

Other impacts not

evaluated.

Super Silt

fence

Modification of standard silt-fence to

improve it structurally.

No validation information is available.

Recommended to be used where

destruction of the silt fence will

destroy critical areas.

More expensive than standard silt

fence.

Database is poor.

No validated urban runoff models

available for theoretical analysis

of downstream impacts.

Some potential exists to modify

existing models to make the

analysis of downstream impacts on

geomorphology.

No good cause-effect

relationships

available.

Other impacts not

evaluated.
Development Document for Construction and Development Proposed Effluent Guidelines

Table 5-27. Summary of Information on Erosion Control and Prevention BMPs

(Sub-section 5.1.5.3)

BMP Type Physical Impact Mitigation Other Impacts

Receiving Water Quality Downstream Impacts

June 2002 5-120

Straw Bale

Dike

Works by impounding water.

Primary trapping mechanism is by

settling behind straw bale dike.

Information on performance is very

limited with much variation in the

limited data.

Should not be used in waterways or as a

perimeter control due to

biodegradation. 

Idealized models of performance are

available for systems that are

properly installed.

Database is poor.

No validated urban runoff models

available for theoretical analysis

of downstream impacts.

Some potential exists to modify

existing models to make the

analysis of downstream impacts on

geomorphology

No good cause-effect

relationships

available.

Other impacts not

evaluated.

Sediment

Traps

Formed by excavation and/or

embankment.

Can simplify stormwater control by

trapping sediment at specific

spots.

Can be installed quickly and serve as

short-term solution to sediment

trapping in small areas.

May require cleanout.

Detailed models as well as simplified

design aids are available to predict

performance in trapping sediment. 

Data on performance are available from

both laboratory studies and field

studies. 

Will likely control only the settleable

solids unless enhanced settling is

developed with chemical

flocculation.

Database is poor.

No validated urban runoff models

available for theoretical analysis

of downstream impacts.

Some potential exists to modify

existing models to make the

analysis of downstream impacts on

geomorphology.

Data for trapping

nutrients are

available, but show

wide variation. 

General models of 

nutrient trapping are

not available.

Other impacts not

evaluated.
Development Document for Construction and Development Proposed Effluent Guidelines

Table 5-27. Summary of Information on Erosion Control and Prevention BMPs

(Sub-section 5.1.5.3)

BMP Type Physical Impact Mitigation Other Impacts

Receiving Water Quality Downstream Impacts

June 2002 5-121

Sediment

Basins

Normally formed by construction of a

dam.

Stormwater detention basin may serve

as sediment basin during

construction.

Can be used for any size watershed.

May require cleanout.

Data on performance are available both

from laboratory studies and field

studies.

Will likely control only the settleable

solids unless enhanced settling is

developed with chemical

flocculation.

Most reliable and stable structure for

obtaining high sediment trapping

efficiency under widely varying

conditions. 

Must consider dam safety issues since

dam failure is a reasonable

possibility.

Structures are relatively large and can

be expensive.

Database is poor.

No validated urban runoff models

available for theoretical analysis

of downstream impacts.

Some potential exists to modify

existing models to make the

analysis of downstream impacts on

geomorphology.

Data for trapping

nutrients are

available, but show

wide variation. 

General models of 

nutrient trapping are

not available.

Other impacts not

evaluated.
Development Document for Construction and Development Proposed Effluent Guidelines

June 2002 5-122

Table 5-28. Summary of Information on Erosion Control and Prevention BMPs 

(Sub-section 5.1.5.4)

BMP Type Physical Impact Mitigation Other Impacts

Receiving Water Quality Downstream Impacts

Stone Outlet

Structures

Porous outlet structure constructed of

dumped rock, used as the outlet

for earth dikes.

Requires a stabilized outlet channel

until the flow reaches a stable

channel.

Data on the effectiveness are limited to

visual observations of field installations

where failure was frequent due to poor

installation.

Models are available to predict the

performance of stone outlets, but field

data have not been collected to evaluate

the accuracy of the model.

No validated urban runoff models

available for theoretical analysis

of downstream impacts.

Some potential exists to modify

existing models to make the

analysis of downstream impacts on

geomorphology.

General models of 

nutrient trapping are

not available.

Other impacts not

evaluated.

Rock Outlet

Protection

Used to reduce velocity of flow in

receiving channel and prevent

scouring.

Very effective when properly installed.

Design procedures are well established.

Maintenance is low, if properly

installed.

Should be inspected after high flows.

No data on impact.

No data available. No data available.

Sump Pit Used to dewater during excavation.

Effectiveness not evaluated.

Potential exists to theoretically evaluate

the BMP’s effectiveness in

trapping sediment.

Could be used at times other than storm

flow, such as removal of

groundwater flow. 

Database is poor.

No validated urban runoff models

available for theoretical analysis

of downstream impacts.

Some potential exists to modify

existing models to make the

analysis of downstream impacts on

geomorphology.

No data available.

Storm Drain

Inlet

Protection

Used to trap sediment that would

otherwise flow into storm drain

inlet. 

Should be installed prior to land

disturbance.

Effectiveness in removing sediment has

not been evaluated, but is thought

to be low during construction.

Potential exists to use computer models

to evaluate effectiveness. 

Cost can be high for maintenance

requirements.

Should not be used as stand-alone

sediment control. 

Database is poor.

No validated urban runoff models

available for theoretical analysis

of downstream impacts.

Some potential exists to modify

existing models to make the

analysis of downstream impacts on

geomorphology.

No data available.

Sediment Tank Portable sediment trap.

Flows are pumped in and out of the

tank.

Used where spaced is limited No

effectiveness data are available.

Expected to be relatively expensive.

No data available. No data available.
Development Document for Construction and Development Proposed Effluent Guidelines

Table 5-28. Summary of Information on Erosion Control and Prevention BMPs 

(Sub-section 5.1.5.4)

BMP Type Physical Impact Mitigation Other Impacts

Receiving Water Quality Downstream Impacts

June 2002 5-123

Stabilized

Construction

Entrance

Used to minimize mud and sediment

attached to motorized vehicles.

Consists of an area that is covered with

rocks over which all vehicles must

drive.

Can be combined with a wash station.

Effective only if all entrances are

maintained. 

Relatively expensive.

Will not remove highly cohesive clays. 

No data available. No data available.

Stabilizes slopes and decreases runoff

velocity.

Can be incorporated into low-impact

development plans.

Not effective when drainage patterns

are altered.

Not effective when vegetative areas on

perimeter are destroyed.

Practiced at virtually all construction

sites.

No data available on BMP

effectiveness.

No data available. No data available.

Temp Access

Waterways

Crossing

Reduces risk to damaging streambed

from construction equipment

tracking.

Can be a bridge, culvert, or ford. 

Bridges and culverts preferred, but

more expensive.

Data on effectiveness in reducing

sediment are not available.

No data available. No data available.

Dust Control Important in arid and semi-arid regions.

Applicable to any construction site.

Construction and sequencing and

limiting exposure area can reduce

problems.

Spray-on adhesives are recommended.

Water application may require near

constant attention.

Excess water may cause runoff or

tracking of mud.

Very limited effectiveness information

available.

Costs can vary widely, depending on

local conditions.

No data available. No data available.
Development Document for Construction and Development Proposed Effluent Guidelines 

June 2000 5-124

5.2 REFERENCES

Adams, J, J. Janatzen, D. Loudenslager. 2000. A Device to Alleviate Pollution from Urban

Stormwater. Design Report, Biosystems and Agricultural Engineering, Oklahoma State

University, Stillwater, OK.

ASCE. 1999, National Stormwater Best Management Practices (BMP) Database, prepared by the

Urban Water Resources Research Council of the American Society of Civil Engineers,

prepared for the US EPA, Office of Science and Technology, Washington, DC. 

http://www.bmpdatabase.org

Barfield, B. J. 2000. Presentation on Nonpoint Source Sediment and Stormwater. University of

Puerto Rico, San Juan, PR.

Barfield, B. J., Barnhisel, R. I., Powell, J. C., Hirschi, M. C., and Moore, I. D. 1983. 

Erodibilities and Eroded Size Distribution of Western Kentucky Mine Spoil and

Reconstructed Topsoil. Final Report for Title III. Institute for Mining and Minerals

Research, University of Kentucky, Lexington, KY.

Barfield, B.J., and Clar, M. 1985. Development of New Design Criteria for Sediment Traps and

Basins. Prepared for the Maryland Resource Administration. Annapolis, MD, pp. 33.

Barfield, B. J., Haan, C. T., Stevens, E., and Hayes, J. C., K. F. Holbrook. 2001. “Engineering

Design Aids for Sediment Control Practices,” Proceedings of the International

Symposium on Soil Erosion Research for the 21st Century. January 3-5, 2001. Honolulu,

Hawaii. Symposium Sponsored and Published by American Society of Agricultural

Engineers. St. Joseph, MI. 

Barfield, B. J. and Hayes, J. C. 1992. Unpublished Results of Field Evaluation of Sediment

Controls in South Carolina Construction Operations. Biosystems and Agricultural

Engineering, Oklahoma State University, Stillwater, OK.

Barfield, B. J. and Hayes, J. C. 1999. Unpublished Results of Field Evaluation of Sediment

Controls in Louisville, KY Construction Operations. Biosystems and

Agricultural Engineering, Oklahoma State University, Stillwater, OK

Barfield, B. J., Hayes, J. C., Fogle, A. W., and Kranzler, K. A. 1996. “The SEDIMOT III - Model

of Watershed Hydrology and Sedimentology,” Proceedings of Fifth Federal Interagency

Sedimentation Conference, Las Vegas, NV. 1996.
Development Document for Construction and Development Proposed Effluent Guidelines 

June 2000 5-125

Barfield, B. J., Moore, I. D., and Williams, R. G. 1979. “Sediment Yield in Surface Mined

Watersheds,” Proceedings Symposium on Surface Mine Hydrology, Sedimentology, and

Reclamation. College of Engineering, University of Kentucky, Lexington, KY.

Barrett, M. E., Kearney, J. E., McCoy, T. G., Malina, J. F.,Charbeneau, R. J. and Ward, G. H. 

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, Austin, TX 78712.

Benik, S. R., B. N. Wilson, D. D. Biesboer, B. Hanse, and D. Stenlund. 1998. The Efficacy of

Erosion Control Products at a MN/DOT Construction Site. Paper No. 982156, American

Society of Agricultural Engineers, St. Joseph, MI

Blench, T. 1970. Regime Theory Design of Canals with Sand Beds. Proceedings of the

American Society of Civil Engineers. 96(IR2): 205-213.

Britton, S. L., Robinson, K. M., and Barfield, B. J. 2001. Modeling the Effectiveness of Silt

Fence. Proceedings 7th Federal Interagency Sedimentation Conference, Reno, NV.

Brown, W. and D. Caraco. 1997. “Muddy Water In - Muddy Water Out?”. Article No. 52 in

The Practice of Watershed Protection. Center for Watershed Protection, Ellicott City,

MD. 2000. http://www.stormwatercenter.net 

Brown, W. and T. Schueler. 1997. The Economics of Stormwater BMPs in the Mid-Atlantic

Region. Prepared for: Chesapeake Research Consortium. Edgewater, MD. Center for

Watershed Protection, Ellicott City, MD.

Brown, W., D. Caraco, R. Claytor, P. Hinkle, H.Y. Kwon, T. Schueler, C. Swann, and J.

Zielinski. 1998. Better Site Design: A Handbook for Changing Development Rules in

Your Community. Prepared by Center for Watershed Protection, Ellicott City, MD, for

the Site Planning Roundtable.

Caraco, D. S. 1997. “Keeping Soil in Its Place.” Article No. 55 in The Practice of Watershed

Protection. Center for Watershed Protection, Ellicott City, MD. 2000. 

http://www.stormwatercenter.net 

CWP. 1996. Design of Stormwater Filtering Systems. Prepared for Chesapeake Research

Consortium, Solomons, MD, and U.S. EPA Region 5, Chicago, IL, by Center for

Watershed Protection, Ellicott City, MD.

Chang, H. H. 1988. Fluvial Processes in River Engineering. Wiley Interscience, New York, 

432 p.
Development Document for Construction and Development Proposed Effluent Guidelines 

June 2000 5-126

Claytor, R. 1997. “Practical Tips for Construction Site Phasing.” Article No. 54 in The Practice

of Watershed Protection. Center for Watershed Protection, Ellicott City, MD. 2000. 

http://www.stormwatercenter.net 

Corish, K. 1995. Clearing and Grading Strategies for Urban Watersheds. Environmental Land

Planning Series. Publ. No. 95704. Metropolitan Washington Council of Governments,

Washington, DC. http://www.mwcog.org. 

Coyle, J.J. (USDA). 1979. “Grassed Waterways and Outlets”. Engineering Field Manual for

Conservation Practices. U.S. Department of Agriculture, Soil Conservation Service

(SCS). Ch 7. p. 7-7.

Dorman, M.E., J. Hartigan, R.F. Steg and T. Quasebarth. 1989. Retention, Detention and

Overland Flow for Pollutant Removal from Highway Stormwater Runoff. Vol. 1.

Research Report. Federal Highway Administration. FHWA/RD 89/202. Also in:

“Performance of Grassed Swales along East Coast Highways.” Article No. 114 in The

Practice of Watershed Protection. Center for Watershed Protection, Ellicott City, MD. 

2000. http://www.stormwatercenter.net 

Ellis, B. 1998. A Further Guide to Swales: Costs of Operation and Maintenance. PERMEATE. 

Scottish Environmental Protection Agency, Stirling, Scotland.

http://www.sepa.org.uk/guidance/scontrol/swales.htm

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.

Ettinger, C. E. and J. E. Lichty. 1979. Evaluation of Performance Capability of Surface Mine

Sediment Ponds. Final Report on Contract Number 68-03-2677, Industrial

Environmental Research Laboratory.

Faircloth, W. 1999. “Searching for a Practical, Efficient, Economical Sediment Basin.” In

Proceeding of the 30th Conference of the International Erosion Control Association,

Nashville, TN, Feb. 22-26, pp. 272-282.

Fifield, J. 2000. Designing for Effective Sediment and Erosion Control on Construction Sites.

Forester Press, Santa Barbara, CA.

Fisher, L. S. and Jarrett, A. R. 1984. “Sediment Retention Efficiency of Synthetic Filter Fabric”. 

Transactions of the American Society of Agricultural Engineers. 30(1):82-89.
Development Document for Construction and Development Proposed Effluent Guidelines 

June 2000 5-127

Foster, G. R., Young, R. A., and Neibling, W. H. 1985. “Sediment Composition for Nonpoint

Source Pollution Analyses.” Transaction of the American Society of Agricultural

Engineers. 28(1):133-146.

Goldberg. 1993. Dayton Avenue Swale Biofiltration Study. Seattle Engineering Department,

Seattle, WA.

Griffin, M. L., Barfield, B. J., and Warner, R. C. 1985. “Laboratory Studies of Dead Storage in

Sediment Ponds”. Transactions of the American Society of Agricultural Engineers.

28(3):799-804.

Haan, C. T., Barfield, B. J., and Hayes, J. C. 1994. Design Hydrology and Sedimentology for

Small Catchments. Academic Press, San Diego, CA.

Harding, M.V. 1990. Erosion Control Effectiveness: Comparative Studies of Alternative

Mulching Techniques. Environmental Restoration, pp. 149-156, as 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. 

Harper, H. 1988. Effects of Stormwater Management Systems on Groundwater Quality. Final

Report. Environmental Research and Design, Inc. Prepared for Florida Department of 

Environmental Regulation. Also in: “Runoff and groundwater dynamics of two swales in

Florida. Article No. 113 in The Practice of Watershed Protection. Center for Watershed

Protection, Ellicott City, MD. 2000. http://www.stormwatercenter.net 

Hayes, J. C., B. J. Barfield and R. I. Barnhisel. 1984. Performance of Grass Filters under

Laboratory and Field Conditions. Transactions of the American Society of Agricultural

Engineers 27(5): 1321-1331.

Hayes, J. C. and Barfield, B. J. 1995. “Engineering Aids and Design Guidelines for Control of

Sediment in South Carolina”. In South Carolina Stormwater and Sediment Control

Handbook for Land Disturbance Activities. South Carolina Department of Health and

Environmental Control. Columbia, SC.

Hayes, J. C., Akridge, A. L., Barfield, B. J. and Holbrook, K. F. 2001. “Simplifying Design of

Sediment Controls in Jefferson County, Kentucky”. In Proceedings of Soil Erosion

Research for the 21st Century: An International Symposium and Exhibition, Honolulu,

HI, January 2001. Sponsored by the American Society of Agricultural Engineers.
Development Document for Construction and Development Proposed Effluent Guidelines 

June 2000 5-128

Herrera, N. M. and G. K. Felton. 1991. “Hydraulics of Flow through a Rockfill Dam Using

Sediment-Free Water.” Transactions of the American Society of Agricultural Engineers.

34(3):871-875.

Heyer, T. No Date. Vegetative Measures for Streambank Stabilization. U.S. Department of

Agriculture, Forest Service, St. Paul, MN. 

Hirschi, M. C. 1981. “Efficiency of Small Sediment Controls.” Unpublished Agricultural

Engineering File Report, Agricultural Engineering, University of Kentucky, Lexington,

KY. (Details of the report are given in Chapter 9 of Haan et al, 1994).

Holbrook, K. F., Hayes, J. C. and Barfield, B. J., and A.W. Fogle. 1998. "Engineering Aids and

Design Guidelines for Control of Sediment in South Carolina," In Proceedings of the

International Erosion Control Association Conference. February 1998.

IDNR. 1992. Indiana Handbook for Erosion Controls in Developing Areas, Guidelines for

Protecting Water Quality through the Control of Soil and Erosion and Sedimentation on

Construction Sites. Division of Soil Conservation, Indiana Department of Natural

Resources, Indianapolis, IN.

Jarrett, A. 1999. “Designing Sedimentation Basins for Better Sediment Capture”. In Proceeding

of the 30th Conference of the International Erosion Control Association, Nashville, TN,

Feb. 22-26, pp. 218-233.

Kay-Shoemake, J, M. Watwood, R. Sojka, and R. Lentz. 2000. “Soil Amidase Activity in

Polyacrylamide (PAM) Treated Soils and Potential Activity toward Common Amide

Containing Agrochemicals”. Biology and Fertility of Soils 31(2): 183-186. 

Kercher, W.C., J.C. Landon and R. Massarelli. 1983. “Grassy Swales Prove Cost-Effective for

Water Pollution Control. Public Works 16: 53-55.

Knisel, W. G., ed. 1980. CREAMS: A Field-Scale Model for Chemicals, Runoff, and Erosion

from Agricultural Management Systems. U. S. Department of Agriculture, Conservation

Research Report No. 26, 640 pp.

Koon, J. 1995. Evaluation of Water Quality Ponds and Swales in the Issaquah/East Lake

Sammamish Basins. King County Surface Water Management and Washington

Department of Ecology, Seattle, WA.

Kouwen, N. 1990. Silt Fences to Control Sediment on Construction Sites. Technical

Publication MAT-90-03, Research and Development Branch, Ontario Ministry of

Transportation, 1201 Wilson Avenue, Downsview, Ontario, Canada M3M 1J8.
Development Document for Construction and Development Proposed Effluent Guidelines 

June 2000 5-129

Lane, E. W. 1955. “The Importance of Fluvial Geomorphology in Hydraulic Engineering”. 

Proceedings of the American Society of Civil Engineers, 81: 1-17.

Leopold, Luna B., M. Gordon Wolman, and John P. Miller, 1964. Fluvial Processes in

Geomorphology. Dover Publications, Inc. Mineola, NY.

Lindley, M., B. J. Barfield, J. Ascough, B. N. Wilson, and E. Stevens. 1998. “The Surface

Impoundment Element for WEPP”. Transactions of the American Society of Agricultural

Engineers. 41(3):555-564. 

Masters, A., K. A. Flahive, S. Mostaghimi, D. Vaughan, A. Mendez, M. Peterie, S. Radke. 2000. 

A Comparative Investigation of the Effectiveness of Polyacrylamide (PAM) for Erosion

Control in Urban Areas. Paper No. 002176, American Society of Agricultural Engineers,

St. Joseph, MI, pp. 21.

McBurnie, J. C., Barfield, B. J., Clar, M. L. and Shaver, E. 1990. “Maryland Sediment

Detention Pond Design Criteria and Performance”. Applied Engineering in Agriculture. 

6(2):167-173.

MDE. 1994. Maryland Standards and Specifications for Soil Erosion and Sediment Control. 

Water Management Administration, Maryland Department of the Environment, Soil

Conservation Service, and State Soil Conservation Committee, Baltimore, MD.

NAHB. No Date. NAHB Research Center Storm Water Runoff & Nonpoint Source Pollution

Control Guide for Builders and Developers. National Association of Home Builders,

Washington, DC.

NCDNR. 1988. North Carolina Erosion and Sediment Control Planning and Design Manual.

North Carolina Sedimentation Control Commission, the North Carolina Department of

Natural Resources and Community Development, and the North Carolina Agricultural

Extension Service, Raleigh, NC.

Oakland, P.H. 1983. “An Evaluation of Stormwater Pollutant Removal through Grassed Swale

Treatment.” In Proceedings of the International Symposium of Urban Hydrology,

Hydraulics and Sediment Control, H. J. Sterling, Lexington, KY.

Occoquan Watershed Monitoring Laboratory. 1983. Final Report: Metropolitan Washington

Urban Runoff Project. Prepared for the Metropolitan Washington Council of

Governments. Manassas, VA.
Development Document for Construction and Development Proposed Effluent Guidelines 

June 2000 5-130

Pitt, R. and J. McLean. 1986. Toronto Area Watershed Management Strategy Study: Humber

River Pilot Watershed Project. Ontario Ministry of Environment and Energy, Toronto, 

Ontario, Canada. 

Roa-Espinosa, A., G.D. Bubenzer, and E.S.Miyashita. 2000. Sediment and Runoff Control on

Construction Sites Using Four Application Methods of Polyacrylamide Mix. National

Conference on Tools for Urban Water Resource Management and Protection, Chicago,

IL, February 7-10, 2000, pp. 278- .

Renard, K. G., Foster G. R., Weesies, G. A., McCool, KD. K. and Yoder D. C. 1994. Predicting

Soil Erosion by Water—A Guide to Conservation Planning with the Revised Universal

Soil Loss Equation (RUSLE). Agricultural Research Service Publication, U.S.

Department of Agriculture.

Rosgen, D. L., 1996. Applied River Morphology. Wildland Hydrology, Pagosa Springs, CO.

Seattle Metro and Washington Department of Ecology. 1992. Biofiltration Swale Performance:

Recommendations and Design Considerations. Publication No. 657. Water Pollution

Control Department, Seattle, WA. Also in: Watershed Protection Techniques. Fall 1994

1(3): 117-119.

SCDHEC. 1995. South Carolina Stormwater Management and Sediment Reductions

Regulations. In South Carolina Stormwater Management and Sediment Control

Sedimentology Resource, South Carolina Department of Health and Environmental

Control. Columbia, SC. 

Schumm, S. A. 1977. The Fluvial System. John Wiley and Sons, New York. 338 pp.

Simons, D.B., and M.L. Albertson, 1960. “Uniform Water Conveyance Channels in Alluvial

Material.” Proceedings of the American Society of Civil Engineers. 86(HY5):33-71.

Smiley, J., and C. T. Haan. 1976. “The Dam Problem of Urban Hydrology”. Proceedings of the 

National Symposium on Urban Hydrology, Hydraulics, and Sediment Control. College

of Engineering, University of Kentucky, Lexington, KY. 

Smolen, M.D., D.W. Miller, L.C. Wyall, J. Lichthardt, and A.L. Lanier. 1988. Erosion and

Sediment Control Planning and Design Manual. North Carolina Sedimentation Control

Commission and North Carolina Department of Natural Resources and Community

Development, Raleigh, NC. 
Development Document for Construction and Development Proposed Effluent Guidelines 

June 2000 5-131

Snodgrass, W.J., B.W. Kilgour, L. Leon, N. Eyles, J. Parish, and D.R. Barton. 1998. “Applying

Ecological Criteria for Stream Biota and an Impact Flow Model for Evaluation of 

Sustainable Urban Water Resources in Southern Ontario”. In: Sustaining Urban Water

Resources in the 21st Century. Proceedings for an Engineering Foundation Conference. 

Edited by A.C. Rowney, P. Stahre, and L.A. Roesner. Malmo, Sweden. September 7 -

12, 1997.

Stahre, P., and B. Urbonas. 1990. Stormwater Detention For Drainage, Water Quality, and

CSO Management. Prentice Hall, Englewood Cliffs, NJ. 

SWRPC. 1991. Costs of Urban Nonpoint Source Water Pollution Control Measures. Technical

report no. 31. Southeastern Wisconsin Regional Planning Commission, Waukesha, WI. 

Tobiason, S., D. Jenkins, E. Molash, and S. Rush. 2000. “Polymer Use and Testing for Erosion

and Sediment Control on Construction Sites: Recent experience in the Pacific

Northwest”. In: Proceedings of Conference 31. International Erosion Control

Association. Palm Spring, CA, February 21-25, 2000, pp. 41-52.

Tapp, J. S., and Barfield, B. J. 1986. “Modeling the Flocculation Process in Sediment Ponds”.

Transactions American Society of Agricultural Engineers. 29(3):741-747.

Tapp, J. S., Barfield, B. J., and Griffin, M. L. 1981. Predicting Suspended Solids Removal in

Pilot Scale Sediment Ponds Utilizing Chemical Flocculation. Research Report IMMR

81/063, Institute for Mining and Minerals Research, University of Kentucky, Lexington,

KY.

UNEP. 1994. Guidelines for Sediment Control Practices in the Insular Caribbean. CEP

Technical Report No. 32. UNEP Caribbean Environment Programme, Kingston,

Jamaica. http://www.cep.unep.org/pubs/techreports/tr32en/content.html

USAF. 1998. USAF Landscape Design: Erosion Control Measures. U.S. Air Force, St. Paul,

MN. 

http://www.afcee.brooks.af.mil/ldg/s18erosioncontrol/c03process.html 

 

USDOT. 1995. Best Management Practices for Erosion and Sediment Control. Report No.

FHWA-FLP-94-005. Eastern Federal Lands Highway Design, U.S Department of

Transportation, Sterling, VA. 

USDA and NRCS, 1985. National Engineering Handbook. Natural Resources Conservation

Service, Soil Conservation Services. 
Development Document for Construction and Development Proposed Effluent Guidelines 

June 2000 5-132

USEPA. 1971. Control of Sediment Resulting from Construction of Highways and Land

Development. U.S. Environmental Protection Agency, Washington, DC. 

USEPA. 1992. Storm Water Management for Construction Activities: Developing Pollution

Prevention Plans and Best Management Practices. EPA 832-R-92-005. U.S.

Environmental Protection Agency, Office of Water, Washington, DC. 

USEPA. 1992. Storm Water Management for Industrial Activities: Developing Pollution

Prevention Plans and Best Management Practices. EPA 832-R-92-006. U.S.

Environmental Protection Agency, Office of Water, Washington, DC.

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. 

USEPA. 2000. Urban Nonpoint Source Management Measure Guidance - Draft. U.S.

Environmental Protection Agency, Office of Water, Washington, DC.

Vanderwel, D. and S. Abday. 1998. An Introduction to Water Erosion Control. Alberta,

Agriculture, Food and Rural Development, Alberta, Canada. 

VDCR. 1995. Virginia Erosion & Sediment Control Field Manual. Second Edition. Virginia

Department of Conservation and Recreation, Division of Soil and Water Conservation,

Richmond, VA. 

VDCR. 2001. Virginia Erosion and Sediment Control Law, Regulations, and Certification

Regulations. Virginia Department of Conservation and Recreation, Division of Soil and

Water Conservation, Richmond, VA. 

Wang, T., D. Spyridakis, B. Mar and R. Horner. 1981. Transport, Deposition and Control of

Heavy Metals in Highway Runoff. FHWA-WA-RD-39-10. Department of Civil

Engineering. University of Washington, Seattle, WA.

Ward, A. D., Haan, C. T., and Barfield, B. J. 1977. Simulation of the Sedimentology of Sediment

Detention Basins. Research Report No. 103, Water Resources Research Institute,

University of Kentucky, Lexington, KY.

Ward, A. D., Haan, C. T., and Tapp, J. S. 1979. The DEPOSITS Sedimentation Pond Design

Manual. OISTL, Institute for Mining and Minerals Research, University of Kentucky,

Lexington, KY.
Development Document for Construction and Development Proposed Effluent Guidelines 

June 2000 5-133

Washington State Department of Ecology (WDEC). 1992. Stormwater Management Manual for

the Puget Sound Basin. Technical Manual. Washington State Department of Ecology,

Olympia, WA.

Welborn, C., and J. Veenhuis. 1987. Effects of Runoff Controls on the Quantity and Quality of

Urban Runoff in Two Locations in Austin, TX. U.S. Geological Survey Water Resources

Investigations Report. 87-4004, pp. 88.

Williams, J. R. No Date. “Sediment Yield Prediction with Universal Equation Using Runoff

Energy Factor”. Present and Prospective Technology for Predicting Sediment Yields and

Sources. Publication ARS-S-40, Agricultural Research Service, U.S. Department of

Agriculture, Washington, DC. 

Wilson, B. N., and Barfield, B. J. 1984. “A Sediment Detention Pond Model Using CSTRS

Mixing Theory.” Transactions American Society of Agricultural Engineers. 27(5):1339-

1344.

Wilson, B. N., Barfield, B. J., and Moore, I. D. 1982. A Hydrology and Sedimentology

Watershed Model. Department of Agricultural Engineering, University of Kentucky,

Lexington, KY.

Wischmeier, W. H. and D. D. Smith. 1965. Predicting Rainfall-Erosion Losses From Cropland

East of the Rocky Mountains-Guide for Selection of Practices for Soil and Water

Conservation. U. S. Department of Agriculture, Agricultural Handbook No. 282. 47 pp.

Wishowski, J. M., Mamo, M., and Bubenzer, G. D. 1998. Trap Efficiencies of Filter Fabric

Fence. Paper No 982158, American Society of Agricultural Engineers, St. Joseph, MI.

Wyant, D. C. 1980. Evaluation of Filter Fabric for Use as Silt Fences. VA Highway and

Transportation Research Council, Richmond, VA.

WYDEQ. 1999. Urban Best Management Practices for Nonpoint Source Pollution. Point and

Nonpoint Source Programs, Water Quality Division, Wyoming Department of

Environmental Quality, Cheyenne, WY. 

http://deq.state.wy.us/wqd/watershed/92171.pdf

Yousef, Y., M. Wanielista, H. Harper, D. Pearce and R. Tolbert. 1985. Best Management

Practices: Removal of Highway Contaminants by Roadside Swales. Final report.

University of Central Florida. Florida Department of Transportation. Orlando, FL. Also

in: “Pollutant Removal Pathways in Florida Swales”. Watershed Protection Techniques. 

Fall 1995. 2(1): 299-301.
Development Document for Construction and Development Proposed Effluent Guidelines 

June 2000 5-134

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, pp. 60. 

Also in: Performance of Grassed Swales Along East Coast Highways. Article No. 114 in

The Practice of Watershed Protection. Center for Watershed Protection, Ellicott City,

MD. 2000. http://www.stormwatercenter.net 
Development Document for Construction and Development Proposed Effluent Guidelines

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SECTION 6: REGULATORY DEVELOPMENT AND RATIONALE

In this section, the methodology used by EPA to develop regulatory options for the construction

and land development industry is described. EPA methodology first evaluated the pollutants

discharged from the industry and evaluated existing Federal, State and local control strategies

designed to manage impacts. Based on this analysis, EPA was able to identify several key

components of existing regulatory strategies that would be applicable for national effluent

guidelines regulations and develop regulatory options around these existing strategies. Following

development of regulatory options, EPA evaluated the costs and environmental benefits of

several options and determined the appropriate option for proposal based on factors such as total

costs, monetized and non-monetized environmental benefits, ease of implementation, industry

financial impacts, and industry acceptance. The following sections describe the components of

this process involving identification of impacts, evaluation of available control strategies, and

formulation of regulatory options. Costs of regulatory options are discussed in Section 7 of this

document while a description of the environmental benefits estimation and industry financial

analyses can be found in the other supporting documents of this regulation (USEPA, 2002 and

2002a).

6.1 IDENTIFICATION OF INDUSTRY IMPACTS

In developing effluent guidelines for controlling storm water discharges associated with

construction and land development activities, EPA identified pollutants that are attributable to

the industry. In addition to pollutants discharged from construction sites and from long-term

storm water discharges, EPA also looked at the broader range of environmental impacts that the

land development process influences and that could potentially be addressed under effluent

guidelines regulations. These categories include physical impacts to receiving streams due to the

increased frequency of high flow rates and associated discharge of sediment, as well as thermal

impacts to receiving waters due to the increased temperature of storm water discharges.

These analyses helped EPA to develop regulatory options and associated estimates of costs and

benefits for temporary erosion and sediment controls. This approach allowed for the evaluation

of different combinations of regulatory options when developing an overall regulatory strategy

for this industry, with different combinations addressing various impact areas.

6.1.1 Pollutant Indicators

When determining which pollutants to assess, EPA applied the following priorities for 

construction storm water discharges:

• Focus on pollutants directly attributable to the industry, using indicator pollutants where

necessary;
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• Focus on pollutants most commonly encountered under most settings, (i.e., not to preconstruction site contamination issues or accidental discharges);

• Focus on pollutants that are most manageable given the current suite of available

technologies; and

• Focus on pollutants that can be addressed under the authority of effluent guidelines.

EPA conducted an extensive evaluation of the literature to identify pollutants present in storm

water discharges from construction and land development sites. While the literature contains

extensive information on pollutants present in storm water discharges from urban areas, there

were little data available on pollutants present in storm water discharges from construction sites

during the active construction phase other than for sediment, TSS and turbidity. This is not

surprising, since construction site storm water management is primarily concerned with the

control of solids from exposed soil areas. There is the potential for other pollutants to be

discharged from construction sites depending on factors such as prior land uses. For example, if

the prior land use was agriculture, there is the potential for discharge of pollutants such as

nutrients and pesticides. Likewise, areas of redevelopment that occur on sites where previous

land uses included industry could discharge pollutants such as organics and metals. In addition,

pollutants such as metals and nutrients can be present in native site soils, and could be discharged

from construction sites. However, EPA was not able to identify sufficient data in the literature to

warrant development of controls specific to pollutants other than sediment, TSS and turbidity in

storm water discharges from construction sites. Some literature suggests that pollutants adhere to

sediment so regulating TSS should also act as a control for other pollutants.

There are extensive data in the literature describing pollutants present in storm water discharges

from urban areas. The most comprehensive evaluation of urban storm water was the Nationwide

Urban Runoff Program (NURP) (USEPA, 1983). While somewhat dated, the NURP results are

still valid, and serve as a primary means of characterizing urban runoff pollutants. In addition to

NURP, a variety of other analyses conducted over the past 20 years have contributed greatly to

the understanding of pollutants present in urban storm water runoff. Literally thousands of

references can be found in the literature summarizing hundreds of studies evaluating urban runoff

pollutant levels. As a result, there are sufficient data available to identify the major pollutants

expected to be discharged from new land development activities. Based on these data sources,

EPA identified sediments (measured as TSS), nutrients and metals as pollutants of concern for

this industry. EPA also evaluated the inclusion of organics, pesticides, and bacteria as potential

pollutants of concern, but the literature indicates that control of these pollutants through

conventional storm water management strategies is potentially much more difficult, and that

there are little data linking their presence in storm water discharges directly with new land

development activities. Source control may factor greatly into controlling these pollutant

sources.

Although EPA identified a number of pollutants of concern for this industry, EPA did not

develop regulatory options specifically targeted at controlling each of these individual pollutants. 
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1

 Not all pollutant indicators listed above are directly used by EPA in its benefits

assessment, or in developing the C&D effluent guidelines. Nevertheless, EPA has collected data

to estimate all of the measures for potential future consideration of this and other

industries/activities.

 June 2002 6-3

Instead, EPA chose to develop regulatory options using an indicator pollutant, TSS. While TSS

levels may not be directly correlated with all pollutants of concern, it is certainly the most widely

reported parameter in the literature due to its relative ease of collection and low cost. In addition,

design of management systems for the control of TSS will likely result in control of pollutants

such as sediment, nutrients and metals that are present in the solid-phase (attached to sediments). 

The one pollutant of concern that may not have a strong correlation with TSS is turbidity, since

particles that contribute to turbidity may not be removed through conventional storm water

management practices that control TSS. Particles that contribute to turbidity may be of such a

fine grain that they will not be removed by the mechanisms whereby most BMPs operate, mainly

settling and filtration. 

EPA’s assessment of pollutant loadings for the industry was based on mathematical models. 

These models were developed using analyses prepared by EPA for the NPDES Phase II

rulemaking (USEPA, 1999), established hydrologic principles and storm water monitoring data

from the literature. EPA estimated annual loadings with and without effluent guidelines from

construction site storm water discharges using 225 site models which varied based on location,

site size and site slope. In its assessment of the industry, EPA elected to use the estimated land

area constructed annually in the nation for the contiguous states, based on the National Resources

Inventory (NRI)(USDA, 2000). EPA did not develop estimates of pollutant loadings for Alaska,

Hawaii, and the U.S. territories, due to a several factors, such as a lack of rainfall data and lack of

data on annual land development. However, due to the small amount of development that occurs

in these areas, the omission of these areas from the analysis is not expected to contribute a

significant error to EPA’s national estimates.

In developing pollutant loadings of the land development industries, a distinction was made

between primary pollutant loadings (e.g., discharge of sediments from disturbed ground surfaces)

and secondary pollutant loadings (e.g., loadings resulting from accelerated erosion of streams

caused by increased high flows from urbanized land uses). This distinction was made because

studies focusing on the impacts of land development have sometimes neglected the secondary

pollutant loadings that result when changes to hydrology cause downstream channels to become

unstable. The secondary pollutant loadings that occur year after year from increased stream

flows have not been well inventoried.1
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2

 Not all physical/habitat measures listed above are directly used by EPA in its benefits

assessment, or in developing the C&D effluent guidelines. Nevertheless, EPA has collected data

to estimate all of the measures for potential future consideration of this and other

industries/activities.

 June 2002 6-4

6.1.2 Physical/Habitat Indicators

In addition to assessing impacts of the construction and land development industry due to

discharge of pollutants in storm water, EPA also developed a methodology for assessing the

physical and habitat impacts caused by changes in hydrology and stream flow. Land

development activities cause significant alterations in the natural hydrologic regime of

developing watersheds. The removal of vegetation, the compaction of soils by construction

equipment and the construction of impervious surfaces such as roads, driveways and buildings

causes a marked increase in the total volume and peak flow rate of storm water discharges as

compared to forested, open and agricultural land uses. As a result, streams receiving storm water

discharges will frequently undergo significant channel alterations in order to adjust to the altered

hydrologic regime. This alteration results in mobilization of high quantities of sediment and

associated water quality problems.

EPA’s assessment attempted to develop an impacts time line, predicting when certain impacts

will occur. Due to its relatively short duration, construction impacts (or benefits) were assumed

to occur within a single year. The assessment of long-term impacts was based on the 30 year

period immediately following conversion into urban land use. This includes characterization of

physical/habitat impacts related to hydrologic changes (e.g., increased flooding and stream

erosion) and changes in runoff characteristics (e.g., runoff thermal signature). In its modeling

effort, EPA made assumptions that simplify (spatial and temporally) land development,

compressing the period required for land to reach “build-out.” EPA performed sensitivity

evaluations to verify that these simplifications do not distort or abrogate its assessment of

potential environmental impacts. 

Physical/Habitat Measures Estimated by EPA2 include:

• Miles of stream urbanized (located within the area urbanized nationally in a single year)

• Number of new stream crossings expected to become fish migration barriers

• Acres of stream habitat lost to new stream crossings

• Acres of stream-side area flooded by the 100-year rainfall event

• Tons of stream bank/bed sediment removed as a result of increased high flow rate frequency

A detailed discussion of EPA’s environmental assessment methodology and results is presented

in other supporting documents of this rule (USEPA, 2002 and 2002a).
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6.2 DEVELOPMENT OF REGULATORY OPTIONS

In developing effluent guidelines for the construction and development industries, EPA evaluated

a variety of state and local programs to identify various management strategies and regulatory

components that would be applicable on a national basis. For erosion and sediment control and

other temporary BMPs, EPA considered a series of regulatory options. These options are

designed to control the discharge of sediment, storm water and other pollutants from sites when

construction is taking place. EPA considered a range of options that incorporate varying levels

of management and various control strategies. Because long-term storm water management is

beyond the scope of the controls proposed by EPA, the following discussion only presents

information related to options for controlling storm water during the active phase of construction.

The following discussion presents various options that EPA considered.

Codify the EPA Construction General Permit

EPA considered an option that would essentially codify the provisions contained in EPA's

construction general permit (CGP) (USEPA, 1998) as minimum national standards for erosion

and sediment control (i.e., for all states, not only those with EPA as permitting authority) for sites

of 5 acres or more of disturbed land. Requirements include preparing a Storm Water Pollution

Prevention Plan (SWPPP) or equivalent, provisions for installing and sizing sediment basins on

sites with more than 10 acres of disturbed land, requirements for providing cover on exposed soil

areas within 14 days after construction activity has ceased, and installation and maintenance of

other erosion and sediment control practices and other temporary BMPs on all construction sites,

such as silt fencing, seeding and mulching, diversion dikes and berms, sediment traps, storm

drain inlet protection, channel liners, erosion control blankets and mats, stabilized construction

entrances, litter, trash and debris control, discarded building material control, and concrete truck

wash water control.

Numerical Design Requirements

EPA considered an option that would establish numerical requirements for the design of

sediment basins and traps based on local or regional rainfall patterns and site-specific soil types. 

This options could be similar to existing requirements designed for managing storm water

discharges, where sediment controls are sized based on a specified rainfall return frequency (such

as the 2-year, 24-hour storm), or a specified runoff frequency (such as the 90th percentile runoff

event).

Numerical Pollutant Removal Requirements

EPA considered options that would contain numerical requirements for the removal of specific

pollutants from construction site runoff. EPA initially considered targeting a variety of pollutants
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 June 2002 6-6

including sediment, TSS, turbidity, nutrients, metals and other priority pollutants, however there

are little data available supporting the feasibility of controlling pollutants other than sediment (or

associated indicator parameters such as TSS, turbidity, total suspended sediment, or settleable

solids). This option could be expressed as either a percent removal through sediment controls

(such as sediment basins or traps), or as a total site reduction (incorporating consideration of

sheet flow and diffuse runoff in addition to discrete conveyances). In addition to establishing

numerical requirements for the control of sediment, EPA preliminarily considered establishing

requirements for removing fine-grained and slowly- or non-settleable particles contained in

construction-site runoff (such as turbidity). This option would likely have relied primarily on

chemical treatment of soils or construction site runoff using polymers or coagulants such as alum

in order to prevent the non-settleable fractions of solids from being transported off-site. 

Discharge Monitoring

EPA considered the inclusion of monitoring requirements for evaluating the effectiveness of

erosion and sediment controls. Monitoring of storm water discharges from construction sites

could be used to evaluate the effectiveness of individual sediment controls (such as sediment

basins), or monitoring the receiving water above and below construction sites. Monitoring

requirements could be incorporated with any of the previously discussed regulatory options

considered.

Inspection and Certification

EPA considered an option that includes mandatory site inspection, maintenance and reporting

provisions by site owners and operators in order to improve confidence in the implementation

and performance of construction site erosion and sediment controls. These certification

provisions may be accomplished either through self-inspection by a qualified employee of the

owner and operator (such as a professional engineer or person trained in erosion and sediment

control techniques) or inspection by a third-party (such as a consulting firm). The certification

provisions would consist of a checklist-type certification form that the permittee would be

required to complete at various stages of the project to certify that the provisions contained in the

permittee's SWPPP are being implemented. In addition, the permittees would be required to

conduct periodic inspections in order to confirm that the permittee is conducting the maintenance

necessary to maintain the functionality of BMPs. The specific activities requiring certification

include: SWPPP preparation; installation of perimeter controls and sediment controls; site

inspections every 14 days; final stabilization of exposed soils and removal of temporary erosion

& sediment controls. The certification and inspection forms would be retained on the site, and

made available to the permitting authority and the public upon request. 
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6.3 REGULATORY OPTIONS DEVELOPED FOR THE PROPOSED RULE

6.3.1 Option 1 - Inspection and Certification

Option 1 proposed by EPA would establish the site inspection and certification provisions

discussed above as minimum requirements for all construction sites subject to the NPDES storm

water regulations. This includes sites from 1 up to 5 acres that will be required to obtain a permit

once the Phase II regulations are implemented and sites 5 acres or greater that are required to

obtain a permit under the Phase I regulations. The permittee would be required to conduct

periodic inspections and provide certifications as to certain activities (such as SWPPP

preparation, BMP installation, periodic maintenance, etc.). Under this option, these inspections

and certifications would be performed by a qualified professional, such as a registered

professional engineer or person trained in erosion and sediment control. The permittee may

provide self-certifications if qualified.

The specific inspection and certification provisions can be found in the proposed rule language

and are summarized below:

Site log book. The permittee would be required to maintain a record of site activities in a site log

book. The specific requirements and information contained in the log book consists of the

following:

(1) A copy of the site log book would be required to be maintained on site and be made

available to the permitting authority upon request. EPA recommends that the permittee also

make a copy of the site log book available to the public upon request within a reasonable

period;

(2) In the site log book, the permittee shall certify, prior to the commencement of construction

activities, that any plans required by the permit meet all Federal, State, Tribal and local

erosion and sediment control requirements and are available to the permitting authority;

(3) The permittee would be required to have a qualified professional conduct an assessment of

the site prior to groundbreaking and certify that the appropriate BMPs described in plans

required by the permit have been adequately designed, sized and installed to ensure overall

preparedness of the site for initiation of groundbreaking activities. The permittee would be

required to record the date of initial groundbreaking in the site log book. The permittee

would also be required to identify and conduct any soil stabilization and BMP maintenance

requirements identified in the permit within 48 hours of their identification;

(4) The permittee would be required to post at the site, in a publicly-accessible location, a

summary of the site inspection activities on a monthly basis. EPA recommends that the

permittee provide contact information for obtaining a copy of the site inspection log book;
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Site Inspections. The permittee or designated agent of the permittee (such as a consultant,

subcontractor, or third-party inspection firm) would be required to conduct regular inspections of

the site and record the results of such inspection in the site log book. Specific inspection

provisions include:

(1) After initial groundbreaking, permittees would be required to conduct site inspections at

least every 14 calendar days and within 24 hours of the end of a storm event of 0.5 inches or

greater. These inspections would be required to be conducted by a qualified professional. 

During each inspection, the permittee or designated agent would be required to conduct the

following activities and record the following information: 

(i) Indicate the extent of all disturbed site areas and drainage pathways. Indicate site

areas that are expected to undergo initial disturbance or significant site work

within the next 14-day period;

(ii) Indicate all areas of the site that have undergone temporary or permanent

stabilization;

(iii) Indicate all disturbed site areas that have not undergone active site work during

the previous 14-day period;

(iv) Inspect all sediment control practices and note the approximate degree of

sediment accumulation as a percentage of the sediment storage volume (for

example 10 percent, 20 percent, 50 percent, etc.). Note all sediment control

practices in the site log book that have sediment accumulation of 50 percent or

more; and

(v) Inspect all erosion and sediment control BMPs and note compliance with any

maintenance requirements such as verifying the integrity of barrier or diversion

systems (e.g., earthen berms or silt fencing) and containment systems (e.g.,

sediment basins and sediment traps). Identify any evidence of rill or gully erosion

occurring on slopes and any loss of stabilizing vegetation or seeding/mulching. 

Document in the site log book any excessive deposition of sediment or ponding

water along barrier or diversion systems. Note the depth of sediment within

containment structures, any erosion near outlet and overflow structures, and verify

the ability of rock filters around perforated riser pipes to pass water.

(2) Prior to filing of the Notice of Termination or the end of permit term, the permittee or

designated agent would be required to conduct a final site erosion and sediment control

inspection. The inspector would be required to certify that the site has undergone final

stabilization as required by the permit and that all temporary erosion and sediment controls

(such as silt fencing) not needed for long-term erosion control have been removed.
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 June 2002 6-9

6.3.2 Option 2 - Codify EPA CGP Requirements with Site Inspection and Certification

Provisions

Option 2 proposed by EPA would require the permittee to prepare a storm water pollution

prevention plan (SWPPP) and implement the erosion and sediment controls contained in the

EPA CGP. In addition, the permittee would be required to conduct periodic site inspections and

provide certifications in a site log book. This option would only apply to sites with 5 or more

acres of disturbed land. The details of this option can be found in the proposed rule language and

are summarized below:

General Erosion and Sediment Controls

Each SWPPP would be required to include a description of appropriate controls designed to

retain sediment on site to the extent practicable. These general erosion and sediment controls

would be required to be included in the SWPPP described below. The SWPPP would be

required to include a description of interim and permanent stabilization practices for the site,

including a schedule of when the practices will be implemented. Stabilization practices may

include:

(1) Establishment of temporary or permanent vegetation;

(2) Mulching, geotextiles, or sod stabilization;

(3) Vegetative buffer strips;

(4) Protection of trees and preservation of mature vegetation.

EPA recommends that all controls be properly selected and installed in accordance with sound

engineering practices and, when feasible, manufacturer's specifications.

Sediment Controls

Operators would be required to design and install structural controls to divert flows from exposed

soils, store flows or otherwise limit runoff and the discharge of pollutants from exposed areas

and to describe controls in the SWPPP. These controls are as follows:

(1) For common drainage locations that serve an area with 10 or more acres disturbed at one

time, the operator would be required to provide a temporary (or permanent) sediment basin

that provides storage for a calculated volume of runoff from a 2 year, 24-hour storm from

each disturbed acre drained, or equivalent control measures, where attainable until final

stabilization of the site. Where no such calculation has been performed, the operator would

be required to provide a temporary (or permanent) sediment basin providing 3,600 cubic feet
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 June 2002 6-10

feet of storage per acre drained, or equivalent control measures, where attainable until final

stabilization of the site. When computing the number of acres draining into a common

location it is not necessary to include flows from off-site areas and flows from on-site areas

that are either undisturbed or have undergone final stabilization where such flows are

diverted around both the disturbed area and the sediment basin.

(2) In determining whether a sediment basin is attainable, the operator may consider factors

such as site soils, slope, available area on site, etc. In any event, the operator would be

required to consider public safety, especially as it relates to children, as a design factor for

the sediment basin. Use of alternative sediment controls would be required where site

limitations preclude a safe basin design.

(3) For portions of the site that drain to a common location and have a total contributing

drainage area of less than 10 acres, the operator would be required to consider installation of

sediment traps or other sediment control devices.

(4) Where neither a sediment basin nor equivalent controls are attainable due to site limitations,

the operator would be required to install silt fences, vegetative buffer strips or equivalent

sediment controls for all down slope boundaries of the construction area and for those side

slope boundaries deemed appropriate for individual site conditions.

Pollution Prevention Measures

The operator would be required to implement the following pollution prevention measures:

(1) The operator would be required to prevent litter, construction chemicals, and construction

debris from becoming a pollutant source in storm water discharges; and

(2) The operator would be required to contain construction and building materials in

appropriate storage areas and manage the materials to prevent contamination of storm water

runoff.

Storm Water Pollution Prevention Plan

Permittees would be required to compile Storm Water Pollution Prevention Plans (SWPPPs)

prior to groundbreaking at any construction site. In areas where EPA is not the permit authority,

operators may be required to prepare documents that may serve as the functional equivalent of a

SWPPP. Such alternate documents would satisfy the requirements for a SWPPP so long as they

contain the necessary elements of a SWPPP. A SWPPP would be required to incorporate the

following information:
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 June 2002 6-11

(1) A narrative description of the construction activity, including a description of the intended

sequence of major activities that disturb soils on the site (Major activities include any

clearing, grubbing, excavating, grading, soil stockpiling, and utilities and infrastructure

installation, or any other activity that results in significant disturbance of soils.);

(2) A general location map (e.g., portion of a city or county map) and a site map. The site map

shall include descriptions of the following:

(i) Drainage patterns and approximate slopes anticipated after major grading

activities;

(ii) The total area of the site and the area of the site that is expected to be disturbed by

excavation, clearing, grading and other construction activities during the life of

the permit;

(iii) Areas that will not be disturbed;

(iv) Locations of erosion and sediment controls identified in the SWPPP;

(v) Locations where stabilization practices are expected to occur;

(vi) Locations of off-site material, waste, borrow or equipment storage areas;

(vii) Surface waters (including wetlands); and

(viii) Locations where storm water discharges to a surface water;

(3) A description of available data on soils present at the site;

(4) A description of BMPs to be used to control pollutants in storm water discharges during

construction

(5) A description of the general timing (or sequence) in relation to the construction schedule

when each BMP is to be implemented;

(6) An estimate of the pre-development and post-construction runoff coefficients of the site;

(7) The name(s) of the receiving water(s);

(8) Delineation of SWPPP implementation responsibilities for each site owner or operator;

(9) Any existing data that describe the storm water runoff characteristics at the site (such as data

that may be collected during a site assessment), and

Updating the SWPPP

The operator would be required to amend the SWPPP and corresponding erosion and sediment

control BMPs whenever:
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 June 2002 6-12

(1) There is a change in design, construction, or maintenance that is expected to have a

significant effect on the discharge of pollutants; or

(2) Inspections or investigations by site operators, local, State, Tribal or Federal officials

indicate that any BMPs described in the SWPPP are ineffective in eliminating or

significantly minimizing pollutant discharges.

Site Log Book/Certification

The operator would be required to maintain a record of site activities in a site log book, as part of

the SWPPP. The site log book shall be maintained as follows:

(1) A copy of the site log book would be required to be maintained on site and be made

available to the permitting authority upon request. EPA recommends that the operator make

a copy of the site log book available to the public upon request within a reasonable period;

(2) In the site log book, the operator would be required to certify, prior to the commencement of

construction activities, that the SWPPP meets all Federal, State and local erosion and

sediment control requirements and is available to the permitting authority;

(3) The operator would be required to have a qualified professional conduct an assessment of

the site prior to groundbreaking and certify that the appropriate BMPs and erosion and

sediment controls described in the SWPPP have been adequately designed, sized and

installed to ensure overall preparedness of the site for initiation of groundbreaking activities. 

The operator would be required to record the date of initial groundbreaking in the site log

book. The operator would be required to certify that the site inspections, soil stabilization

activities, and maintenance activities required by the proposed rule have been satisfied

within 48 hours of actually meeting such requirements;

(4) The operator would be required to post at the site, in a publicly-accessible location, a

summary of the site inspection activities on a monthly basis. EPA recommends that the

operator provide contact information for obtaining a copy of the SWPPP and a copy of the

site inspection log book;

Site Inspections

The operator or designated agent of the operator (such as a consultant, subcontractor, or thirdparty inspection firm) would be required to conduct regular inspections of the site and record the

results of such inspection in the site log book. The specific activities that would require

inspection and certification are:
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 June 2002 6-13

(1) After initial groundbreaking, operators would be required to conduct site inspections at least

every 14 calendar days and within 24 hours of the end of a storm event of 0.5 inches or

greater. These inspections would be required to be conducted by a qualified professional. 

During each inspection, the operator or designated agent would be required to record the

following information: 

(i) On a site map, indicate the extent of all disturbed site areas and drainage

pathways. Indicate site areas that are expected to undergo initial disturbance or

significant site work within the next 14-day period;

(ii) Indicate on a site map all areas of the site that have undergone temporary or

permanent stabilization;

(iii) Indicate all disturbed site areas that have not undergone active site work during

the previous 14-day period;

(iv) Inspect all sediment control practices and note the approximate degree of

sediment accumulation as a percentage of the sediment storage volume (for

example 10 percent, 20 percent, 50 percent, etc.). Record all sediment control

practices in the site log book that have sediment accumulation of 50 percent or

more; and

(v) Inspect all erosion and sediment control BMPs and record all maintenance

requirements such as verifying the integrity of barrier or diversion systems

(earthen berms or silt fencing) and containment systems (sediment basins and

sediment traps). Identify any evidence of rill or gully erosion occurring on slopes

and any loss of stabilizing vegetation or seeding/mulching. Document in the site

log book any excessive deposition of sediment or ponding water along barrier or

diversion systems. Record the depth of sediment within containment structures,

any erosion near outlet and overflow structures, and verify the ability of rock

filters around perforated riser pipes to pass water.

(2) Prior to filing of the Notice of Termination or the end of permit term, a final site erosion and

sediment control inspection would be required to be conducted by the operator or designated

agent. The inspector would be required to certify that the site has undergone final

stabilization using either vegetative or structural stabilization methods and that all

temporary erosion and sediment controls (such as silt fencing) not needed for long-term

erosion control have been removed. 

Stabilization

The operator would be required to initiate stabilization measures as soon as practicable in

portions of the site where construction activities have temporarily or permanently ceased, but in

no case more than 14 days after the construction activity in that portion of the site has

temporarily or permanently ceased. This provision would not apply in the following instances:
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 June 2002 6-14

(1) Where the initiation of stabilization measures by the 14th day after construction activity

temporarily or permanently ceased is precluded by snow cover or frozen ground conditions,

the operator shall initiate stabilization measures as soon as practicable;

(2) Where construction activity on a portion of the site is temporarily ceased, and earthdisturbing activities will be resumed within 21 days, temporary stabilization measures need

not be initiated on that portion of the site.

(3) In arid areas (areas with an average annual rainfall of 0 to 10 inches), semi-arid areas (areas

with an average annual rainfall of 10 to 20 inches), and areas experiencing droughts where

the initiation of stabilization measures by the 14th day after construction activity has

temporarily or permanently ceased is precluded by seasonably arid conditions, the operator

shall initiate stabilization measures as soon as practicable.

Maintenance

The operator would be required to remove accumulated sediment from sediment traps and ponds

identified as having sediment accumulation greater than 50 percent to restore the original design

capacity,

6.3.3 Option 3 - No Regulation

EPA also considered an option that would not establish effluent guidelines requirements for this

industry.

6.4 REFERENCES

USDA. 2000. 1997 National Resources Inventory. U.S. Department of Agriculture, Natural

Resources Conservation Service. Washington, DC. 

http://www.nrcs.usda.gov/technical/NRI/

USEPA. 1983. Final Report of the Nationwide Urban Runoff Program. U.S. Environmental

Protection Agency. Washington DC.

USEPA. 1998. Reissuance of NPDES General Permits for Storm Water Discharges from

Construction Activities. ("Construction General Permit.") Federal Register, Vo. 63, No. 31,

p. 7858. February 17, 1998. Washington, DC. 

http://cfpub.epa.gov/npdes/stormwater/cpermit.cfm?program_id=6

USEPA. 1999. Economic Analysis of the Final Phase II Storm Water Rule. U.S. Environmental

Protection Agency. Washington, DC.
Development Document for Construction and Development Proposed Effluent Guidelines

 June 2002 6-15

USEPA. 2002. Economic Analysis of Proposed Effluent Limitation Guidelines and New Source

Performance Standards for the Construction and Development Category; May 2002. EPA

821-R-02-008. http://www.epa.gov/waterscience/guide/construction/

USEPA. 2002a. Environmental Assessment for Proposed Effluent Limitation Guidelines and

New Source Performance Standards for the Construction and Development Category; May

2002. EPA 821-R-02-009. http://www.epa.gov/waterscience/guide/construction/
Development Document for Construction and Development Proposed Effluent Guidelines

June 2002 7-1

SECTION 7: APPROACH TO ESTIMATING COSTS

7.1 OVERVIEW

This section describes EPA’s methodology for estimating compliance costs associated with

implementing the regulatory options proposed for the construction and land development effluent

limitation guidelines (ELG). EPA estimated three distinct cost categories: (1) erosion and

sediment control (ESC) costs, including design, installation, operation, and maintenance; 

(2) administrative costs to permittees for activities such as site inspections and certification

activities; and (3) administrative costs to permit authorities to incorporate the effluent guidelines

requirements into general permits. Costs contained in categories (1) and (2) are expected to be

borne directly by the construction and development industry.

Costs were evaluated individually for 24 site size class and land use types. EPA developed a

series of model sites for each land use/site size class and estimated costs of proposed options for

each of these model sites. Using estimates of the population of new construction acreage

developed using data from the USDA’s National Resources Inventory (NRI), the U.S. Census

Bureau, EPA’s NPDES Storm Water Phase II rulemaking, and other national data sources

(described in Section 3 of this document), EPA summed the model site costs to the national

level. A description of this methodology is presented in the Economic Analysis document

(USEPA, 2002).

The total costs of the proposed rule options are presented in Table 7-1.

Table 7-1. Total Costs of Proposed Rule Options

Option Annual Cost (millions 2000 dollars)

1 - Inspection and Certification sites 1 acre 126

2 - Codify EPA Construction General Permit (CGP)

with Inspection and Certification sites 5 acres

502

3 - No Regulation 0

7.2 METHODS FOR ESTIMATING EROSION AND SEDIMENT CONTROL COSTS

7.2.1 OVERVIEW

EPA used four land use types to account for variations in construction operations and associated

ESCs employed for various development types. For each land use type, EPA evaluated six site

size classes to account for economies of scale that might occur with certain best management

practice (BMP) design and installation costs (some BMPs are employed only if the site size is
Development Document for Construction and Development Proposed Effluent Guidelines

June 2002 7-2

greater than a threshold value). EPA also considered regional cost adjustments due to variations

in labor, supply, and material costs (see Table 7-2). EPA used an industry standard reference to

establish appropriate adjustment factors for regional compliance costs (R.S. Means, 2000). 

The costing analysis started by allocating the estimated annual construction acreage and number

of model sites developed in Section 4 (see Table 4-21) for one of 19 EPA-developed ecoregions

shown in Figure 7-1 (see the Environmental Assessment supporting document (EPA, 2002a) for

a complete description of the EPA ecoregions). Matrices of standard BMP quantities for the

technology-based option (Option 2) were developed for the various model site sizes using the

NPDES Phase II economic analysis (USEPA, 1999) and the Agency’s engineering judgement. 

By multiplying the two matrices, the total quantity of BMPs for all of the model sites was

determined. EPA estimated the unit costs of each BMP element using R.S. Means (2000), and

data from “The Economics of Stormwater Treatment: An Update” from the Center for Watershed

Protection’s (CWP’s) book entitled The Practice of Watershed Protection (Schueler, 2000). 

Regional costs were adjusted using cost adjustment factors from R.S. Means (2000), and data

were summed across the different site size categories to determine engineering costs at the

national level. Additional costs for factors such as design and contingencies (described in the

Economic Analysis) were added to these national costs to arrive at the national cost figures

presented in Table 7-1. All costs presented are incremental over current costs to the industry

from existing Federal and State requirements.

EPA used a similar approach to estimate administrative costs to permittees for conducting the

site inspection and certification provisions contained in Options 1 and 2. EPA estimated the

number of site inspections needed and the hours required for conducting site inspections and

certifications for each of the model site sizes. By multiplying these hour estimates by a

professional labor rate, EPA was able to estimate the total administrative costs to permittees. 

Similarly, EPA estimated the administrative costs to permitting authorities to revise general

permits to incorporate the effluent guideline requirements by multiplying the estimated hours per

entity by the number of entities to arrive at the national costs.
Development Document for Construction and Development Proposed Effluent Guidelines

June 2002 7-3







 

























	

	

 











Figure 7-1. EPA Ecoregions

Source: Composited from Omernik, 1987.
Development Document for Construction and Development Proposed Effluent Guidelines

June 2002 7-4

Table 7-2. Regional Compliance Cost Adjustment Factors

EPA

Hydrologic

Region

Regional Compliance Cost

Adjustment Factor

1 0.855

2 0.984

3 0.900

4 0.782

5 0.857

6 0.858

7 0.870

8 1.032

9 0.877

10 0.996

11 0.810

12 0.854

13 0.936

14 0.908

15 1.094

16 1.129

17 1.052

18 1.046

19 1.052

Source: EPA hydrologic regions are composited

from Omernik, 1987. Regional compliance cost

adjustment factors are computed based on city

data from R.S. Means, 2000.

7.2.2 EROSION AND SEDIMENT CONTROL COSTS

In this analysis, EPA has built upon a number of previous assessments of ESC practices,

including the Economic Analysis of the Final Phase II Storm Water Rule (USEPA, 1999). EPA

estimated types and quantities of ESC BMPs that are commonly employed under baseline

conditions during construction activities to mitigate impacts from construction site runoff for 24

land use/site size class models. In addition, in its analysis EPA estimated that requirements
Development Document for Construction and Development Proposed Effluent Guidelines

June 2002 7-5

contained in existing State construction general permit requirements (or, in the non authorized

states, the region-specific EPA construction general permits (CGPs) would be fully implemented. 

Although Phase II is not fully implemented at this time, the requirements will be implemented by

the time final action is taken on these proposed effluent guidelines. Furthermore, as proposed

Option 2 (the only option for which EPA is establishing technology-based requirements)

addressed only sites with 5 or more acres of disturbed land, the timing of Phase II

implementation is not an issue.

EPA took a model site approach to estimating the baseline ESC usage and quantities of

materials, as well as design costs and operation and maintenance (O&M) costs that are expected

to be applicable given a range of physical conditions (1 to 7 percent land slopes and different soil

types). Table 7-3 lists the construction site BMPs included in the baseline analysis for various

site sizes. To establish baseline BMP usage, EPA started with the model site estimates generated

during the Phase II rulemaking, scaling up the BMP quantities to sites larger than 5 acres, and

adding sediment basins for larger sites. In the final costing analysis of this option, costs for

BMPs for sites less than 5 acres were eliminated, consistent with the proposed regulatory

requirements for Option 2.

Table 7-3. Construction Site ESC BMP Descriptions and Site Thresholds

ESC BMP Description Applicable Site Sizes for 

ESC BMP Quantity Estimates

Silt Fence, Diversion Dike, Construction Entrances, Stone Check Dams > 1 acre

Mulch > 1 acre

Sediment Traps > 1 acre and < 10 acres

Polyacrylamide (PAM) > 1 acres

Sediment Basins  10 acres

BMP Installation and SWPPP Certifications  1 acre

Site Inspections  1 acres

To determine costs of the regulatory options, EPA first evaluated a variety of State construction

general permits and erosion and sediment control regulations and found that many States have

requirements similar to those contained in the EPA construction general permit, which is the
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1

 Although EPA attempted to obtain comprehensive information, the Agency was not

able to verify the presence of the specific components in Table 7-4 for all States. As a result, the

absence of an entry does not necessarily mean that the State does not currently have an

equivalent requirement.

June 2002 7-6

basis for the requirements contained in Option 2 (see Table 7-4)1. In evaluating existing State

programs, EPA specifically examined the major provisions contained in Option 2, namely

sediment basins designed to provide 3,600 cubic feet per acre of storage; requirements for

stabilization of exposed soil areas within 14 days of reaching final grade; and site inspections at

least every 14 days. In addition, EPA evaluated whether the annual precipitation in each State is

less than 20 inches, since the soil stabilization requirements are linked to this condition. In the

final analysis of national costs, EPA adjusted the estimates of the national costs for the effluent

guidelines to account for States with programs equivalent to EPA’s proposed options. Table 7-5

summarizes the percentage of national costs eliminated due to equivalent State programs. This is

only applicable to Option 2, as EPA has not determined that a significant number of States have

requirements equivalent to Option 1.

It is expected that on some construction sites there will be some portion of land with steeper

slopes and more erosive soils, which will require more intensive management if built upon than

is assumed by EPA’s model. Also, a State with less than 20 inches of annual rainfall was

considered to be equivalent to a State that has the 14-day cover requirement when assessing

overall equivalence. Local regulations may require use of ESCs that are more stringent than the

Phase I and II requirements. However, EPA expects that the BMPs selected to develop its model

sites are representative of baseline conditions for the majority of construction activity across the

nation.
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June 2002 7-7

Table 7-4. Components of Existing State Erosion and Sediment Control Requirementsa

State

Minimum of 3,600

Cubic Feet per Acre

Sediment Basin

Requirement

Inspections

Required at Least

Every 14 Days

14- Day or Less

Stabilization

Requirement

States with Less than

20 Inches of

Precipitation Per

Year

Alabama

Alaska Yes Yes Yes

Arizona Yes Yes Yes Yes

Arkansas 

California Yes Yes Yes

Colorado Yes

Connecticut Yes Yes Yes

Delaware 

District of

Columbia

Florida 

Georgia 

Hawaii 

Idaho Yes

Illinois Yes 

Indiana 

Iowa Yes Yes Yes 

Kansas 

Kentucky 

Louisiana 

Maine 

Maryland 

Massachusetts Yes Yes Yes 

Michigan 

Minnesota 
Development Document for Construction and Development Proposed Effluent Guidelines

State

Minimum of 3,600

Cubic Feet per Acre

Sediment Basin

Requirement

Inspections

Required at Least

Every 14 Days

14- Day or Less

Stabilization

Requirement

States with Less than

20 Inches of

Precipitation Per

Year

June 2002 7-8

Mississippi 

Missouri 

Montana Yes Yes

Nebraska 

Nevada Yes

New Hampshire Yes Yes Yes 

New Jersey 

New Mexico Yes Yes Yes Yes

New York 

North Carolina 

North Dakota Yes

Ohio Yes Yes 

Oklahoma Yes 

Oregon 

Pennsylvania Yes Yes Yes 

Rhode Island 

South Carolina Yes Yes Yes 

South Dakota Yes Yes Yes Yes

Tennessee Yes Yes Yes 

Texas Yes Yes Yes 

Utah Yes Yes Yes Yes

Vermont 

Virginia Yes Yes Yes

Washington 

West Virginia Yes Yes

Wisconsin
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State

Minimum of 3,600

Cubic Feet per Acre

Sediment Basin

Requirement

Inspections

Required at Least

Every 14 Days

14- Day or Less

Stabilization

Requirement

States with Less than

20 Inches of

Precipitation Per

Year

June 2002 7-9

Wyoming Yes Yes

a. Information is accurate as of May 2002

Table 7-5. State Acreage Equivalent to Proposed Option 2

Equivalent State

Acreage for 

Sites >5 acres

Percent of Annual

(>5 acre) Developed

Acreage Equivalent

Option 2 755,500 41

Once EPA estimated the quantities of ESC BMPs for the model sites, the total baseline cost of

BMP installation was calculated from unit costs provided by R.S. Means (2000) and cost curves

from “The Economics of Stormwater Treatment: An Update” (Schueler, 2000). R.S. Means

provides national average unit costs that include materials, installation, and labor. Typically,

users of R.S. Means adjust the national unit costs up or down to obtain their local estimates based

on city-specific adjustment factors provided by R.S. Means. As described previously, EPA

developed and used the regional adjustment factors in Table 7-2 to customize unit costs on an

ecoregion basis, not on a city basis. To compute region-specific unit costs from the national

average value, city-specific adjustment factors provided by R.S. Means were converted into

ecoregion values. First, State-average adjustment factors were estimated based on the values for

cities they contained. Then ecoregion values were computed based on area-weighting for those

states that fell within each ecoregion.

Although R.S. Means is expected to accurately estimate the as-built cost for a particular element,

in certain cases it might underestimate the cost that a developer or ultimate property owner might

need to pay a contractor to construct a particular element. This is due to additional site-specific

cost factors that a contractor may build into a bid package, such as contingencies, allowances for

change orders, additional time and labor for unseen delays due to weather, unanticipated

problems with soils, etc. However, for the majority of projects, R.S. Means is expected to

provide accurate cost information. In addition, EPA adjusted for contingency costs in its

analysis of economic impacts to the industry (see the Economic Analysis document for a

description of this methodology).

In calculating the total costs for erosion and sediment control activities, EPA added estimated

design, operation, and maintenance costs. Table 7-6 shows design and O&M costs as a fraction

of the capital cost of ESC BMPs. These cost ratios were obtained from published sources such
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June 2002 7-10

as the CWP report and from the Agency’s engineering judgement.

In evaluating the proposed rule options, EPA used the model site approach to first determine the

baseline compliance costs, then to modify BMP sizing and BMP quantities to assess the

incremental costs of regulatory options of the proposed rule. The resulting suite of BMPs

evaluated by EPA in establishing costs of the proposed rule are listed in Table 7-7, along with

their unit costs. Appendix B contains additional tables indicating EPA’s estimates of the

standard quantity needed for each BMP listed in Table 7-7, for each land use type and site size.

In addition, Appendix B indicates, for key BMPs, the number of equal size BMPs of a single

type that EPA estimates will be needed to serve a single site (i.e., a single 200-acre site will be

served by four equal-size sediment basins, each of which manages 50 acres).

Table 7-6. Construction ESC BMP Design and Operation and Maintenance Costs

as a Percentage of Capital Costs

Costed Items Effective Life in

Years

Design Costs as

Percent of

Construction Cost

Estimated O&M as Percent of

Original Installation Costs

Silt Fence 1 6% 100%

Diversion Dike 1 6% 10%

Mulch 1 6% 2%

Construction Entrance 1 6% 5%

Stone Check Dam 1 6% 5%

Sediment Trap 1 6% 20%

Sediment Basin 1 6% 25%

Polyacrylamide (PAM) 1 6% 0
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June 2002 7-11

Table 7-7. Evaluated Construction Site BMPs that Augment the Suite of Baseline BMPs

BMP

Description Costing Rationale

Erosion and Sediment Controls

Sediment Basins

for Sites 10

acres

Standardization to 3,600 cubic feet of storage per watershed acre. Cost based on equation

for installing permanent dry detention pond, computed from the equation: 

[8.16 x (volume required, cu. ft./number of ponds per site size)0.78] (Schueler, 2000).

Mulch Mulching of any denuded surface would be required within 14 days of reaching final grade,

resulting in more frequent mulching of a portion of the site acreage. Cost of mulching is

estimated to be $0.23 per square yard for materials/installation (R.S. Means). For sites

larger than 1 acre, mulching is based on the total site acreage less the area where structures

are being built (estimated as the site impervious coverage). The maximum coverage for

single-family and multifamily residential development is 50% of the total site area,

assuming the remaining acreage is maintained as open space and/or permanent

vegetation/cover is installed.

Polyacrylamide

(PAM) 

EPA estimates that a single application of PAM would be used as a temporary stabilization

method until final cover can be installed. PAM was estimated to be appropriate for only

20% of construction sites due to physical constraints. PAM is costed at $200 per acre

treated based on a survey of commercial vendors and the assumption that its application is

similar to that of herbicide for soil treatment ($0.04 per square yard based on spraying from

truck) (R.S. Means). The acreage treated is equal to the site size times the ultimate

impervious area, to a maximum of 50% of the site size.

 Site Administration BMPs

Site Certifications For each site, certification activities include certification of storm water pollution

prevention plan (SWPPP) completion, certification of BMP installations, and certification

of final stabilization prior to filing of the notice of termination (NOT). Certification adds an

estimated cost of approximately $11 per acre for Options 1 and 2.

Site Inspections For each 10-acre unit in the total site, incremental inspection activities over baseline are: (a)

post-BMP installation; (b) once during building; and (c) at end of construction (prior to

filing of the NOT). Inspection adds an estimated cost of approximately $45 per acre for

Options 1 and 2.

Table 7-8 indicates the relative change in quantities of BMPs associated with Options 1 and 2.

Standard quantities of BMPs outlined in Table 7-3 were increased or decreased according to

multiplication factors in Table 7-8 to reflect changes expected due to each option. For example,

in the case of mulch, EPA estimates that under Option 2, there will be a net increase in the use of

mulch by 20 percent over baseline levels, in part to help meet the requirements for 14-day

coverage of denuded areas. In the case of PAM, EPA anticipates that PAM will be applied to 20

percent of the denuded acreage, as it is an inexpensive and effective means to improve erosion

control. 
Development Document for Construction and Development Proposed Effluent Guidelines

June 2002 7-12

Table 7-8. BMP Quantity Adjustment Factors for Baseline and Proposed Options

BMP Type Baseline

Construction

Option1 Inspection/

Certification

Option 2 Inspection/

Certification with

Codification of CGP

Silt Fence 1.0 1.0 1.0

Runoff Diversion 1.0 1.0 1.0

Mulch 1.0 1.0 1.2

Construction 1.0 1.0 1.0

Stone Check Dam 1.0 1.0 1.0

Sediment Trap 1.0 1.0 1.0

Sediment Pond 1.0 1.0 1.1

E&S Certification 0.0 1.0 1.1

E&S Inspection 0.0 1.0 1.0

PAM 0.0 0.0 0.2

Using the information in Table 7-8, EPA estimated baseline costs as well as the costs for Options

1 and 2. By subtracting the baseline costs from the cost of each option, EPA was able to estimate

the incremental costs of the proposed options. Table 7-9 indicates the estimated national costs

over baseline of the proposed rule options. Values include design, maintenance, and

opportunity/interest costs. States that are considered to be equivalent to EPA’s proposed options

are removed from the total national cost estimate increases. The proposed rule is expected to

increase compliance costs for ESCs under Option 1 by $126 million, and by $502 million for

Option 2 (year 2000 dollars). Option 3 is not expected to have any incremental costs.
Development Document for Construction and Development Proposed Effluent Guidelines

June 2002 7-13

Table 7-9. National Cost Estimates for Proposed Rule Options

Sector Option 1 Total Cost 

(millions, 1997 dollars)

Option 2 Total Cost 

(millions, 1997 dollars)

Single-family Residential 25.7 129.7

Multifamily Residential 12.7 63.4

Commercial 83.8 296.2

Industrial 4.0 11.8

Total 126.2 501.1

7.3 METHODS FOR ESTIMATING ADMINISTRATIVE COSTS

7.3.1 OVERVIEW

The analysis of administrative costs focused on the costs to permit authorities to incorporate the

effluent guidelines requirements into general permits. Administrative costs are expected to be

borne by both EPA and States (or surrogate agencies such as conservation districts). EPA’s

assessment is conservative in that it assumes that all States will have to incorporate the effluent

guideline requirements into their permits. However, EPA estimates that approximately 41

percent of developed acreage is under state programs that are equivalent to the proposed

requirements contained in Option 2 and, therefore, will not have to modify their permits to

incorporate these requirements.

7.3.2 ADMINISTRATIVE COSTS TO PERMITTEES

When considering the administrative costs to permittees for implementation of the proposed

options, EPA estimated the number of CGPs it expects to be issued each year. Table 7-10

indicates the number of construction sites under permit EPA estimates are associated with

current development rates, categorized by Option. In its analysis, EPA estimated that

construction sites not affected by effluent guidelines (those smaller than 5 acres in Option 2, and

those smaller than 1 acre in Option 1) would not incur administrative costs. 

Annual administrative costs are expected to be borne by construction firms as a result of site

certification and inspection requirements (See Table 7-7). Under Options 1 and 2, site operators

will be required to certify that the Storm Water Pollution Prevention Plan (SWPPP) has been

completed, that BMPs are installed according to the SWPPP, that periodic inspections have been

completed, and that the site has been stabilized prior to filing of the notice of termination (NOT). 

EPA estimated that it will take 16 hours per 10 acres developed to meet the inspection

requirement. (For construction sites smaller than 10 acres only 16 hours of inspection is
Development Document for Construction and Development Proposed Effluent Guidelines

June 2002 7-14

required.) EPA used the estimates of construction projects by size presented in Table 4-21 to

estimate the total hours required to perform administrative activities.

EPA estimated the total national costs associated with site certifications to be $27,712,000 per

year under Option 1 and $16,727,000 per year under Option 2 (1997 dollars). Based on a review

of States with greater than 50,000 acres per year development, EPA estimates that 34 percent of

acres developed are within States with 14-day inspection requirements that are similar to those

proposed under Options 1 and 2. As a result, EPA adjusted downward its estimate of national

site inspection costs to reflect equivalent inspection programs. The total resulting estimates for

site inspection under Options 1 and 2 are $73,161,000 and $44,160,000 per year, respectively. 

EPA’s estimate of the total annual administrative cost for certification and inspection for Option

1 and 2 are $100,873,000 and $60,887,000, respectively. The total annual administrative costs

are lower for Option 2 because sites of less than 5 acres are not regulated. EPA adjusted these

cost estimates upward to reflect opportunity costs, resulting in overall administrative costs to

permittees of $118,141,000 for Option 1 and $71,290,000 for Option 2. An explanation of this

methodology is presented in the Economic Analysis supporting documentation.

7.3.3 ADMINISTRATIVE COSTS FOR GENERAL PERMIT REVISIONS

EPA estimated the total one-time costs for permit authorities to incorporate the erosion and

sediment control effluent guidelines requirements into their general permits. EPA’s estimates of

full time equivalents (FTEs) and costs for each agency to incorporate effluent guidelines

requirements are indicated in Table 7-10. To determine costs of incorporating the effluent

guidelines requirements into existing State CGPs, EPA estimated that each State will require 200

hours to evaluate and then modify general permits to incorporate new requirements. All 50

States were estimated to encounter administrative costs, even though many States already have

general permits that meet some of the proposed requirements. When dividing costs between

Federal and State entities, EPA’s estimated costs will be allocated based on the percentage of

States currently authorized to manage the NPDES program (i.e., 44 of 50, or 88 percent).

Table 7-10. One-Time Hours and Costs to Incorporate Erosion and Sediment Control

Effluent Guidelines Requirements into General Permits (1997 Dollars)

Program Element Federal State

Revise General Permits (hours) 1,200 8,800

Revise General Permits (dollars) $31,000 $229,000
Development Document for Construction and Development Proposed Effluent Guidelines

June 2002 7-15

7.4 REFERENCES

Schueler, Thomas R.. 2000. “The Economics of Stormwater Treatment: an Update”. Article

No.. 68 in the Practice of Watershed Protection. Center for Watershed Protection, Ellicott

City, MD. http://www.stormwatercenter.net

Omernik, James M. 1987. Ecoregions of the Conterminous United States. Annal of the

Association of American Georgraphers. 77(1): 118-125.

R.S. Means. 2000. Site Work & Landscape Cost Data, 19th Edition. R.S. Means Co., Kingston,

MA.

USEPA. 1999. Economic Analysis of the Final Phase Ii Storm Water Rule. U.S. Environmental

Protection Agency. Washington, DC.

USEPA. 2002. Economic Analysis of Proposed Effluent Limitation Guidelines and New Source

Performance Standards for the Construction and Development Category; May 2002. EPA

821-R-02-008. http://www.epa.gov/waterscience/guide/construction/

USEPA. 2002a. Environmental Assessment for Proposed Effluent Limitation Guidelines and

New Source Performance Standards for the Construction and Development Category; May

2002. EPA 821-R-02-009. http://www.epa.gov/waterscience/guide/construction/
Development Document for Construction and Development Proposed Effluent Guidelines

June 2002 

APPENDIX A:

STATE REGULATIONS ON THE CONTROL OF CONSTRUCTION 

 STORM WATER
Table A-1: State Regulations on the Control of Construction Phase Storm Water

Geographic Area Name

Disturbed 

Area Limit 

for Permet 

Coverage 

(feet2)

Numeric Standard 

or Pollutant 

Reduction 

Requirement

Minimum Depth of 

Runoff or Storm Return 

Frequency to Treat for 

Water Quality 

Management (per acre)

Maximum Allowed 

Denuded Acreage or 

Soil Stablilization 

Requirement

Visual Inspection 

Frequency Notes

Clean Water Act NPDES Storm Water program for Phase I and Phase II MS4s

43,560 After 0.5 inch 

rainfall and every 

14 days

Phase II compliance date is March 10, 2003.

CZARA 5,000 Must prepare and implement an approved erosion and 

plan or similar document that contains erosion and sedprovisions.

Alabama 217,800 Turbidity < 50 NTUAlaska (AK) 217,800 TSS > 20 microns 2 year / 6 hour After 0.5 inch 

rainfall and every 7 

days

Inspector must be qualified personnel provided by the d

Arizona 217,800Arkansas 217,800 10year / 24hour Every 7 days Developers must submit erosion and sediment control p

pollution prevention plan before filing a notice of intent. more need temporary or permanent sediment basin. Sacres need sediment traps and silt fences. 

California (CA) 217,800 2 year / 24 hour After 0.5 inch 

rainfall

Inspections will be performed before anticipated storm extended storm events, and after storm events, and onperiod during extended storm events to identify BMP efimplement repairs or design changes as soon as feasibconditions. Discharger is also responsible for inspectinpublic and private roads for sediment. Construction actthe jurisdiction of the California Department of Transpohave separate permit and regulations.

Colorado (CO) 217,800 Any precipitation or 

snowmelt event that 

causes erosion and 

every 14 days

Storm water management plan must be submitted to streview, as well as be retained on site.

Connecticut 217,800 80% TSS reductionDelaware 5,000 80% TSS reduction 0.5 inchFlorida , DEP, Northern District (only applies in NW Florida)

217,800 80% TSS reduction 0.5 inch* *>100 acres, 1 inch rainfall, <100 acres, 0.5 inch rainfal

Florida, South Florida Water Management District (General, Standard General, Noticed General and Individual Permits)

435,600 1 inch

Florida, Southwest Florida Water Management District

217,800 0.5 inch

Florida, St. Johns River Water Management District

217,800 Turbidity <29 NTU

Florida, Suwannee River Water Management District 

43,560 80% TSS reduction 1 inch

Georgia 47,916 Turbidity < 10-25 

NTU*

25 year / 24 hour *<25 nephelometric turbidity units for waters supporting 

fisheries, or <10 nephelometric turbidity units for waters waters.

A-1
Table A-1: State Regulations on the Control of Construction Phase Storm Water

Geographic Area Name

Disturbed 

Area Limit 

for Permet 

Coverage 

(feet2)

Numeric Standard 

or Pollutant 

Reduction 

Requirement

Minimum Depth of 

Runoff or Storm Return 

Frequency to Treat for 

Water Quality 

Management (per acre)

Maximum Allowed 

Denuded Acreage or 

Soil Stablilization 

Requirement

Visual Inspection 

Frequency Notes

Hawaii (HI) 217,800 After 0.5 inch 

rainfall and every 7 

days during dry 

season, every day 

during rainy season

Construction shall be phased for large projects; one phastabilized before another can begin. 50 days maximum pre-construction conditions to temporary stabilization.

Idaho (ID) 217,800 After 0.5 inch 

rainfall and every 

14 days

Illinois 217,800 3,600 cubic feet per acre Every 7 daysIndiana 217,800 Every 7 calendar 

days and within 24 

hours of 0.5 inch of 

precipitation

Iowa 217,800 80% TSS reduction Every 7 daysKansas 217,800 At least once per 

week

Kentucky 217,800 Goal of 80 % TSS 

reduction (compared 

to pre-construction 

conditions)

Louisiana 217,800Maine 217,800 40-80% TSS 

reduction

2 year

Maryland 5,000 80% TSS reduction* 2 year / 24 hour *Based on the average annual TSS loading from all sto

equal to the 2 year/24 hour storm.

Massachusetts 217,800 80% TSS reduction 2 year / 24 hourMichigan 43,560 3,600 cubic feet per acre Encourage weekly 

inspections

Sites >10 acres require onsite temporary basin.

Minnesota 217,800 0.5 inch 1 time every 7 days 

or within 24 hours 

after a significant 

rain event which 

results in runoff 

leaving a 

construction site.

Mississippi 217,800Missouri 217,800 Settleable Solids < 

0.5 -2.5 mL/L/hour*

Periodic *2.5 mL/L/hour for normal land disturbance, 0.5 mL/L/ho

disturbance within sensitive areas.

A-2
Table A-1: State Regulations on the Control of Construction Phase Storm Water

Geographic Area Name

Disturbed 

Area Limit 

for Permet 

Coverage 

(feet2)

Numeric Standard 

or Pollutant 

Reduction 

Requirement

Minimum Depth of 

Runoff or Storm Return 

Frequency to Treat for 

Water Quality 

Management (per acre)

Maximum Allowed 

Denuded Acreage or 

Soil Stablilization 

Requirement

Visual Inspection 

Frequency Notes

Montana (MT) 217,800 2 year / 24 hour After 0.5 inch 

rainfall and every 7 

days

Dischargers must submit with the state application form erosion control plan (SWECP) that resembles EPA's coSWPPP. Permit coverage begins only when Montana Dapproves SWECP. Must also inspect everyday during precipitation or snowmelt periods. A registered PE musplan if site is greater than 20 acres. Also regulate down construction site within 100 feet of a surface water bodysediment and erosion control guidance manual that lists BMPs. If other BMPs are used, they need to be submitthe state for approval. For slopes steeper than 3:1 and vertical feet, surface roughening is required. Filter fencon drainage areas >1acre; sediment traps should only areas > 3 acres; and temporary sediment ponds should drainage areas > 10 acres.

NC 43,560 Y 20 acres total 

disturbance at any given 

time for areas 

discharging to high 

quality waters

Every 7 days

Nebraska 217,800 Once a month.Nevada 217,800New Hampshire 100,000New Jersey 5,000New Mexico 217,800 YNew York 217,800 0.5 inchNorth Dakota 217,800 YOhio 217,800Oklahoma 217,800 3,600 cubic feet per acre Y A vegetated buffer zone of at least 100 ft must be retain

established between the area disturbed during construcor intermittent streams on or adjacent to the constructiobuffer zone at least 50 ft wide must be retained or estabarea disturbed during construction and all ephemeral stTreatment volume is the lesser of 3,600 or the runoff vohour storm.

Oregon (OR) 217,800 Every 7 days, and 

daily during periods 

of stormwater runoff 

and snowmelt 

runoff; only every 

14 days during 

periods of 7 days or 

more of nonconstruction 

activity.

If site is >20 acres, erosion and sediment control plan ma Professional Engineer, or Registered Landscape ArchProfessional in Erosion and Sediment Control, and plan 90 days before construction begins. All permittees musLand Use Compatibility Statement if they do not already with Oregon DEQ.

Pennsylvania 217,800 5 year Y Basins should drain no quicker than 4 days and no long

A-3
Table A-1: State Regulations on the Control of Construction Phase Storm Water

Geographic Area Name

Disturbed 

Area Limit 

for Permet 

Coverage 

(feet2)

Numeric Standard 

or Pollutant 

Reduction 

Requirement

Minimum Depth of 

Runoff or Storm Return 

Frequency to Treat for 

Water Quality 

Management (per acre)

Maximum Allowed 

Denuded Acreage or 

Soil Stablilization 

Requirement

Visual Inspection 

Frequency Notes

Rhode Island 217,800 80-90% TSS 

reduction

10 year

South Carolina >87,120 80% TSS reduction 3,600 cu ft / ac Y Trapping efficiency is a performance based requiremen

major requirements for storm water control plans are: amap, type and location of BMP's, construction sequencdisturbed areas, property line & waters of the state, stagrassing specifications. The minimum required volume management is 3600 cubic feet for a disturbed area of If there is not a sediment basin of 3600 cubic feet and tless than 10 acres, then sediment traps, silt fences, or are needed for sideslope and downslope boundaries foarea. However, the first 0.5 inch rainfall runoff in a 24-hto the coastal counties only.

South Dakota 217,800 5 yearTennessee 217,800 Y The permittee shall maintain records of checks and repTexas 217,800 3,600 cubic feet per acreUtah (UT) 217,800 24 hour OR 1 inch storm 

event

Once every 14 

days, before 

anticipated storm 

events expected to 

cause significant 

runoff, and within 

24 hours of the end 

of a storm that is 

0.5 inch or greater. 

Where sites have been finally or temporarily stabilized, unlikely due to winter conditions, or during seasonal ariareas and semi-arid areas inspections shall be conductevery 30 days. 10yr, 24hr storm event for water quality greater. For areas less than 10 acres, or where calcularunoff for disturbed acres is not performed, a sediment cubic feet of storage per acre drained or equivalent conbe provided. 1) Where the initiation of stabilization meaday after construction activity temporary or permanently by snow cover or frozen ground conditions, stabilization initiated as soon as possible. 2) In arid areas , semi-arid experiencing droughts where the initiation stabilization 14th day after construction activity has temporarily or peprecluded by seasonal arid conditions, stabilization meainitiated as soon as practicable.

Vermont 217,800Virginia 217,800 3,600 cubic feet per acre Y Sediment basins required for sites of 10 acres or more 

final stabilization); for sites <10 acres, same units requisideslope and downslope boundaries of construction sit

Washington (WA), Large Parcel

>43,560 24 hour / 6 month 2 days between October 

1 and April 30 (I.e., the 

wet season); 7 days 

between May 1 to 

September 30 (dry 

season)

A-4
Table A-1: State Regulations on the Control of Construction Phase Storm Water

Geographic Area Name

Disturbed 

Area Limit 

for Permet 

Coverage 

(feet2)

Numeric Standard 

or Pollutant 

Reduction 

Requirement

Minimum Depth of 

Runoff or Storm Return 

Frequency to Treat for 

Water Quality 

Management (per acre)

Maximum Allowed 

Denuded Acreage or 

Soil Stablilization 

Requirement

Visual Inspection 

Frequency Notes

Washington (WA), Small Parcel

<43,560 24 hour / 6 month 2 days between October 

1 and April 30 (I.e., the 

wet season); 7 days 

between May 1 to 

September 30 (dry 

season)

West Virginia 130,680 2 year YWisconsin *217800 YWyoming (WY) 217,800 Turbidity <10-15 NTU Inspect every 7 days, 

except during 

seasonal shutdowns 

and during the period 

following completion 

of construction but 

prior to return of the 

site to "finally 

stabilized" conditions 

and termination of 

coverage, then the 

site must be inspected 

every quarter.

A-5
Development Document for Construction and Development Proposed Effluent Guidelines

June 2002 

APPENDIX B:

SUPPORTING COST DATA
Development Document for Construction and Development Proposed Effluent Guidelines

June 2002 B-1

APPENDIX B: SUPPORTING COST DATA

OVERVIEW

EPA estimated a reference or standard quantity for each costed best management practice (BMP)

that could be applied to construction erosion and sediment controls (ESCs) (e.g., 621 feet of silt

fence for a 3-acre single-family residential construction site). These reference quantities were set

to serve a range of site conditions and slopes consistent with the requirements of the proposed

rule. Reference quantities were not varied between ecoregions but were varied in response to

alternative levels of management (i.e., regulatory options explored by EPA) as shown in Table 

B-1. Note that only where values in Table B-1 differ between options and baseline values is there

expected to be a change in the cost for site ESCs.

Reference quantities of various ESCs (or construction controls) are listed in Tables B-2 through

B-10, along with unit costing and the assumptions used in EPA’s compliance cost assessment. 

Note that for some controls, reference quantities are given in terms of the number of units that

will be constructed (i.e., the number of construction entrances anticipated for a certain size site). 

In addition, where unit costs are nonlinear (i.e., the unit cost varies with the size of the unit), both

a design quantity and a number of units per site size class are required to estimate ESC

compliance costs. An example of this is sediment basins, where the total volume (the site size in

acres times 3,600 cubic feet per acre) is apportioned into a number of installations (i.e., a 70-acre

site is estimated to have 2 installations). This process helps ensure that any economies of scale in

the calculation of compliance costs are reasonable. 

National BMP costs were determined using the following three equations that relate site size

class/land use type models to ESC capital, design, and operation and maintenance costs. Note

that Table B-11 contains the regional adjustment factors that customize cost estimates for the 

19 ecoregions defined by EPA to make its analysis more representative of actual conditions.

Figure B-1 presents a flowchart summarizing the overall costing methodology.
Development Document for Construction and Development Proposed Effluent Guidelines

June 2002 B-2

TRCC RAF L M S N a

Q

N

i

i

i

b

i

= 



 



 



 



 =

* ∑ * * *

1

1 7

TRDC RAF D F L M S N a

Q

N i i

i

i

b

i

= 



 



 













 =

* ∑ * * * *

1

1 7

TROMC RAF O M L M S N a

Q

N i i

i

i

b

i

= 



 



 













 =

* ∑ * * * *

1

1 7

TRCC = Total Regional Capital (Installation) Cost for a site size class/land use model

Qi = Quantity of elements required per installation

Ni = Number of elements required for a single site size class/land use

S = Estimated number of sites in the site size class/land use

a = Multiplier for converting quantity to national average cost in 2000 dollars

b = Exponent for converting quantity to national average cost in 2000 dollars

RAF = Regional adjustment factor for converting national average costs to region-specific costs

LM = Level of management; values between 0 and 2 that indicate the degree of application of the element. A value

of 1 indicates the full application of an element based on the reference condition

TRDC = Total Regional Design Costs

DFi = Design factor, a multiplier which represents the design cost as a percent of capital costs

Qi = Quantity of elements required per installation

Ni = Number of elements required for a single site size class/land use

S = Estimated number of sites in the site size class/land use

a = Multiplier for converting quantity to national average cost in 2000 dollars

b = Exponent for converting quantity to national average cost in 2000 dollars

RAF = Regional adjustment factor for converting national average costs to region-specific costs

LM = Level of management; values between 0 and 2 that indicate the degree of application of the element. A value

of 1 indicates the full application of an element based on the reference condition

LM = Level of management; values between 0 and 2 that indicate the degree of application of the element. A value

of 1 indicates the full application of an element based on the reference condition.

TROMC = Total Regional Operation and Maintenance Costs

OMi = Operation and Maintenance factor, a multiplier which represents the annual operation and maintenance cost

which ensure proper operation of the element

Qi = Quantity of elements required per installation

Ni = Number of elements required for a single site size class/land use

S = Estimated number of sites in the site size class/land use

a = Multiplier for converting quantity to national average cost in 2000 dollars

b = Exponent for converting quantity to national average cost in 2000 dollars

RAF = Regional adjustment factor for converting national average costs to region-specific costs

LM = Level of management; values between 0 and 2 that indicate the degree of application of the element. A value

of 1 indicates the full application of an element based on the reference condition.
Development Document for Construction and Development Proposed Effluent Guidelines

June 2002 B-3

Table B-1. BMP Quantity Adjustment Factors for Baseline and the Proposed Options

Costed Items

Baseline

Construction

Option 1— Inspection/

Certification

Option 2—Inspection/

Certification with

Codification of CGP

Silt Fence 1.0 1.0 1.0

Runoff Diversion 1.0 1.0 1.0

Construction Phasing 0.0 0.0 0.0

Mulch 1.0 1.0 1.2

Seed and Mulch 0.0 0.0 0.0

Construction Entrance 1.0 1.0 1.0

Stone Check Dam 1.0 1.0 1.0

Sediment Trap 1.0 1.0 1.0

Sediment Pond 1.0 1.0 1.1

E&S Certification 0.0 1.0 1.1

E&S Inspection 0.0 1.0 1.0

Polyacrylamide (PAM) 0.0 0.0 0.2

Alum Treatment 0.0 0.0 0.0

Monitoring of Effluent Quality 0.0 0.0 0.0
Development Document for Construction and Development Proposed Effluent Guidelines

June 2002 B-4

Table B-2. Quantities of Erosion and Sediment Control Items For 

Assessing Compliance Costs for the Construction Industry

Site

size Feet of Silt Fence Feet of Diversion Dike

Acres

SinglefamilyMultifamilyCommercialIndustrialSinglefamilyMultifamilyCommercialIndustrial

1 - - - - - - - -

3 621 722 361 361 621 722 361 361

7.5 1,553 1,143 600 600 1,553 1,143 600 600

25 5,175 3,129 2,087 2,087 5,175 3,129 2,087 2,087

70 14,490 5,238 3,492 3,492 14,490 5,238 3,492 3,492

200 41,400 8,853 5,902 5,902 41,400 8,853 5,902 5,902

Both silt fencing and diversion dike lengths were based on 207 feet per acre on the site. 

Costs for new installation of silt fence are based on $0.92/ft length, excluding profit and overhead (R.S.

Means, 2000). 

Costs for new installation of diversion ditch are based on $0.55/ft length installation, excluding profit and

overhead (R.S. Means, 2000).

Table B-3. Quantities of Erosion and Sediment Control Items For 

Assessing Compliance Costs for the Construction Industry

Site Size Mulched Acreage To Control Erosion

Acres Single-family Multifamily Commercial Industrial

1 0.0 0.0 0.0 0.0

3 0.8 0.8 0.8 0.8

7.5 1.9 1.9 1.9 1.9

25 6.3 6.3 6.3 6.3

70 17.5 17.5 17.5 17.5

200 50.0 50.0 50.0 50.0

For sites larger than 1acre, mulching is limited to the site acreage times half the percentage of ultimate

impervious area as a temporary means to stabilize denuded surfaces. The maximum coverage is set to 25%

of the total site acreage. Cost to mulch is set to $0.20 per square yard for materials/installation without

overhead and profit (R.S. Means, 2000).
Development Document for Construction and Development Proposed Effluent Guidelines

June 2002 B-5

Table B-4. Quantities of Erosion and Sediment Control Items For 

Assessing Compliance Costs for the Construction Industry

Site Size Acres Treated with PAM 

Acres Single-family Multifamily Commercial Industrial

1 0.00 0.00 0.00 0.00

3 0.84 1.32 1.50 1.50

7.5 2.10 3.29 3.75 3.75

25 7.00 10.96 12.50 12.50

70 19.60 30.70 35.00 35.00

200 56.00 87.72 100.00 100.00

PAM is costed at $200 per acre per treatment based on a survey of commercial vendors and assuming costs

are similar to herbicide for soil treatment ($0.04 per square yard without profit and overhead based on

spraying from truck). The acreage treated is equal to the site size times the ultimate impervious percentage,

to a maximum of 50% of the site size.

Table B-5. Quantities of Erosion and Sediment Control Items For 

Assessing Compliance Costs for the Construction Industry

The Number of Equal Size Units Installed to Provide Required Protection

Site

Size Number of Stone Check Dam Number of Sediment Trap

Acres

SinglefamilyMultifamilyCommercialIndustrialSinglefamilyMultifamilyCommercialIndustrial

1 0 0 0 0 0 0 0 0

3 0 0 0 0 1 1 1 1

7.5 10 10 10 10 1 1 1 1

25 35 35 35 35 0 0 0 0

70 50 50 50 50 0 0 0 0

200 100 100 100 100 0 0 0 0

For stone check dam, assume approximately one unit per 5 acres for sites larger than 5 acres at a cost of

$45.36 per installation, excluding overhead and profit (Phase II Economic Analysis for Phase II Storm

Water Regulations).

Sediment trap of 3,600 cubic feet per acre served at a cost of $0.22 per cubic foot volume (excludes profit

and overhead).
Development Document for Construction and Development Proposed Effluent Guidelines

June 2002 B-6

Table B-6. Quantities of Erosion and Sediment Control Items For 

Assessing Compliance Costs for the Construction Industry

Site Size Number of Sediment Basins

Acres Single-family Multifamily Commercial Industrial

1 0 0 0 0

3 0 0 0 0

7.5 1 1 1 1

25 2 2 2 2

70 2 2 2 2

200 4 4 4 4

Sediment pond of 3,600 cubic feet per acre served. Cost in dollars is computed from the equation: 

[ 0.76 x 7.47 x (volume required, cubic feet/number of ponds per site size).78] 

The value of 0.76 removes overhead and profit from cost estimate.

Table B-7. Quantities of Erosion and Sediment Control Items For 

Assessing Compliance Costs for the Construction Industry

Site Size Number of Construction Entrances

Acres Single-family Multifamily Commercial Industrial

1 0 0 0 0

3 1 1 1 1

7.5 1 1 1 1

25 1 1 1 1

70 2 2 2 2

200 4 4 4 4

Costs for construction entrance based on $6.92 per square yard (gravel installed) for a footprint covering

100 square yard, excluding profit and overhead (R.S. Means, 2000).
Development Document for Construction and Development Proposed Effluent Guidelines

June 2002 B-7

Table B-8. Quantities of Erosion and Sediment Control Items For 

Assessing Compliance Costs for the Construction Industry

Administrative BMPs for Erosion and Sediment Control

Management

Site Size E&S Site Inspection

Acres Single-family Multifamily Commercial Industrial

1 0 0 0 0

3 1 1 1 1

7.5 1 1 1 1

25 2 2 2 2

70 7 7 7 7

200 20 20 20 20

E&S Site Inspection includes multiple site visits by a certified inspector to verify the proper installation and

operation of ESC BMPs. Values above are the number of half-day site inspections. Costs are based on 16

hours of inspection/documentation time per 10-acre unit of a site, at a rate of $28.44 per hour.

Table B-9. Quantities of Erosion and Sediment Control Items For 

Assessing Compliance Costs for the Construction Industry

Administrative BMPs for Erosion and Sediment Control

Management

Site Size E&S Site Certification of Sedimentation Basins

Acres Single-family Multifamily Commercial Industrial

1 0 0 0 0

3 1 1 1 1

7.5 1 1 1 1

25 1 1 1 1

70 2 2 2 2

200 4 4 4 4

E&S Site Certification includes multiple site visits by a certified inspector to verify the proper installation

of sedimentation basins. Costs based on 2 hours of inspection/documentation by a licensed engineer per 10-

acre unit of a site, at a rate of $56.74 per hour.
Development Document for Construction and Development Proposed Effluent Guidelines

June 2002 B-8

Table B-10. Quantities of Erosion and Sediment Control Items For 

Assessing Compliance Costs for the Construction Industry

Site Size Phasing of Construction 

Acres Single-family Multifamily Commercial Industrial

1 0 0 0 0

3 0 0 0 0

7.5 0 0 0 0

25 2 2 2 2

70 6 6 6 6

200 19 19 19 19

For sites larger than 10 acres, the number of remobilizations required is based on a maximum of 10 acres

denuded at any single time to prevent large unstabilized construction sites. Costs are based on $1,000 per

remobilization.
June 2002 B-9

Table B-11. Regional Compliance Cost Adjustment Factors

Region or Ecoregion Regional Compliance

Cost Adjustment Factors

1 0.85456

2 0.98351

3 0.9

4 0.78103

5 0.85711

6 0.85768

7 0.87

8 1.03221

9 0.877

10 0.99576

11 0.81034

12 0.85357

13 0.93573

14 0.9076

15 1.09438

16 1.1285

17 1.05151

18 1.04609

19 1.05169
Development Document for Construction and Development Proposed Effluent Guidelines

June 2002 B-10 Figure B-1. Overall Costing Methodology