# ENVIRONMENTAL ASSESSMENT (EA)

EPA’S REISSUANCE OF THE NATIONAL POLLUTANT DISCHARGE ELIMITATION SYSTEM (NPDES) GENERAL PERMIT FOR DISCHARGES FROM CONSTRUCTION ACTIVITIES.

DECEMBER 2011Construction and Development NPDES Ge neral Permit Environmental Assessment

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## Acronyms and Abbreviations

ACHP – Advisory Council on Historic Preservation ATS – Active Treatment Systems ATTAINS – Assessment TMDL Tracking and Implementation System AWWA – American Water Works Association BMP – Best Management Practices BOD – Biological Oxygen Demand C&D – Construction and Development cfs – cubic feet per second cm - centimeter CWA – Clean Water Act DO – Dissolved Oxygen EPA – Environmental Protection Agency ERF – Enhanced Reach File ft/s – feet per second g - Gram GIS – Geographic Information System HAB – Harmful Algal Bloom HUC – Hydrologic Unit Code kg/ha – Kilograms per hectare LC – Lethal Concentration m - Meter mgd – Millions of gallons per day
μ g/L – Micrograms per liter mg/L – Milligrams per liter mL/L – Milliliters per liter mm – Millimeter NHD – National Hydrogeography Dataset NID – National Inventory of Dams NLCD – National Land Cover Database NMFS – National Marine Fisheries Service NOAA – National Oceanic and Atmospheric Administration NPDES – National Pollutant Discharge Elimination System NRC – National Research Council NRCS – Natural Resource Conservation Service NRI – National Resources Inventory NTUs – Nephelometric Turbidity Units PAHs – Polycyclic Aromatic Hydrocarbons PTS – Passive Treatment Systems RESIS – Reservoir Sedimentation Survey Information System RF1 – Reach File Version 1.0 SABS - Suspended and Bedded Sediments SAV – Submerged Aquatic Vegetation SDWIS – Safe Drinking Water Information System SPARROW – Spatially Referenced Re gressions on Watershed AttributesConstruction and Development NPDES Ge neral Permit Environmental Assessment

2 SSC – Suspended Sediment Concentration STORET – Storage and Retrieval data warehouse T&E – Threatened and Endangered TDS – Total Dissolved Solids TESS – Threatened and Endangered Species System database TMDL – Total Maximum Daily Load TN – Total Nitrogen TP – Total Phosphorus TSS – Total Suspended Solids U.S. OMB – United States Office of Management and Budget USACE – United States Army Corps of Engineers USDA – United Stated Depa rtment of Agriculture EPA – United States Environmental Protection Agency USFWS – United States Fish and Wildlife Service USGS – United States Geological Survey USLE – Universal Soil Loss Equation WATERS – Watershed Assessment Tr acking & Environmental Results WQI – Water Quality Index WQL – Water Quality Ladder WTP – Willingness To Pay yd3 – cubic yardConstruction and Development NPDES Ge neral Permit Environmental Assessment

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## TABLE OF CONTENTS

1.0 INTRODUCTION 7 1.1 Background 7 1.2 Summary of the Proposed Action 8 1.2.1 Structure/Appearance of Permit 8 1.2.2 Eligibility for Coverage 8 1.2.3 Notification Changes 9

1.2.4. Non-Numeri c Requirement Changes 9 1.3 Clean Water Act, NPDES General Pe rmits, and Effluent Limitation Guidelines 10

1.3.2 Definintion of New Source 12 1.4 Purpose and Need for the Proposed Action 13 1.5 Documents Incorporated by Reference 13

2.0 ALTERNATIVES 15 2.1 Background 15 2.2 Proposed Action and Alterna tives Considered for Review 15

2.2.1 No Action Alternative 15 2.2.2 Proposed Action 17 2.2.3 Description of the Proposed Action 18 2.2.3.1 Non-numeric Effluent Limitations in the Proposed CGP 18 2.2.3.1.2 Erosion and Sediment Control Requirements 18 2.2.3.1.3 Stabilization Requirements 20 2.2.3.1.4 Pollution Prevention Requirements 20 2.2.3.1.5 Best Management Pract ices (BMPs) to Achieve Non-Numeric Effluent Limitations 21

2.2.3.2 Water Quality-Based Effluent Limitations 24

2.2.3.2.2. General Wate r Quality Based Effluent Limitations 24 2.2.3.2.3 Water Quality Based Discharge Limitations for Impaired Waters 24 2.2.3.2.4 Water Quality Based Di scharge Limitations for Tier 2, 2.5, or 3 Waters 25 2.2.3.3 Site Inspections and Corrective Actions 25

2.2.3.4 Stormwater Pollution Prevention Plan (SWPP) Requirements 26

3.0 AFFECTED ENVIRONMENT 27

3.1 Introduction 27Construction and Development NPDES Ge neral Permit Environmental Assessment

4 3.2 Physical Resources 27

3.2.2 Water Resources 27 3.2.2.1 Freshwater Ecosystems 28 3.2.2.2 Marine Ecosystems 29

3.2.2.3 Human Use 30 3.3 Biological Resources 30 3.3.1 Aquatic Vegetation and Wildlife Resources 30

3.3.2 Terrestrial Ve getation and Wildlife Resources 32 3.3.3 Threatened and Endangered Species 33

3.4 Socioeconomic Resources 34

3.4.1 Land Use 34 3.4.2 Population and Housing 35 3.4.3 Transportation 36

3.4.5 Cultural Resources 36

3.4.6 Recreation 37 4.0 ENVRIONMENTAL CONSEQUENCES 39

4.1 Introduction 39 4.2 Basis for Comparison of Alternatives , Approach to Alternatives Analysis 39 4.2.1 Background on the C & D Rule 39 4.2.2 Approach to Comparison of Alternatives 40 4.3 Implementation of Best Management Practices 41 4.3.1 Construction and Site Planning 42

4.3.2 Erosion Control 43

4.3.3 Runoff Control 46

4.3.4 Sediment Control 47 4.3.5 Good Housekeeping/Materials Management 52 4.4 Physical Resources 52

4.4.1 Earth Resources 52

4.4.2 Water Resources 54 4.4.2.1 Freshwater Ecosystems 55 4.4.2.2 Water Quality Index 60

4.4.2.3 Human Use 61Construction and Development NPDES Ge neral Permit Environmental Assessment

5 4.4.3 Cumulative Impacts 66 4.5 Biological Resources 67 4.5.1 Aquatic Vegeta tion and Wildlife Resources 68 4.5.1.1 Primary Producers 68 4.5.1.2 Aquatic Invertebrates 68

4.5.1.3 Fishes 69 4.5.2 Terrestrial Vegetation and Wildlife Resources 70 4.5.3 Threatened and Endangered Species 70 4.5.4 Terrestrial Impacts from the BMP Requirements 71 4.5.5 Cumulative Impacts 72

4.6 Socioeconomic Resources 73

4.6.1 Land Use 74

4.6.2 Water Resources Uses 75 4.6.2.1 Water Quality Index 75

4.6.2.2 Human Uses 75 4.6.3 Population and Housing 79 4.6.4 Demographics 80

4.6.5 Cultural Resources 80 4.6.6 Cumulative Impacts 80

5.0 Other Considerations 82 5.1 Consistency with Other Federal, Stat e, and Local Plans, Policies and Regulations 82 5.1.1 Clean Water Act 401 Water Qu ality Certification by State Water Quality Agencies 82

5.1.2 Endangered Species Act of 1973 82

5.1.3 Section 106 of the National Historic Preservation Act 82

5.1.4 Environmental Justice 83

6.0 References 84

APPENDIX A 91Construction and Development NPDES Ge neral Permit Environmental Assessment

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## TABLES
Table 2-1. Projected Existing Source CGP-Co vered Sites Over the Term of the Proposed CGP 16

Table 2-2. Proposed CGP Erosion a nd Sediment Control Requirements 19

Table 3-1. Some Characteris tic Differences between Lake s, Ponds, and Reservoirs 28

Table 3-2. Common Names of Prevalent Freshw ater, Estuarine, and Saltwater Organisms 31

Table 3-3. Economic Contributi ons by Type of Fishing 37

Table 4-1. eNOI Statisti cs on C&D Industry Applications Under the Existing CGP 41

Table 4-2. Estimation Results for the SPARROW Suspended Sediment Model 57

Table 4-3. Baseline C&D Stormwater Loading Summary and Post-Compliance Reductions 58

Table 4-4. Distribution of TSS Concentration base d on SPARROW Output for RF1 Reaches Receiving C&D Stormwater Discharges 58

Table 4-5. Total RF1 Miles that Receive Di rect C&D Loadings with Improvements in TSS Concentrations 59

Table 4-6. Distribution of TN and TP Concentrations Based on SPARROW Output for RF1 Reaches Receiving Direct C&D Stormwater Discharges 59

Table 4-7. Estimated Pre-Proposed CGP and Post-Proposed CGP Water Quality Improvements 61

Table 4-8. Summary of Bene fits from Reducing Sediment and Other Pollutants in Stormwater Discharges from C&D Sites 62

Table 4-9. Annualized Naviga ble Waterway Dredging, Pre- and Post-CGP Issuance 64

Table 4-10. Estimated Sediment Removed by Reservoir Dredging Under the Baseline Scenario and Reductions Under Op tions 4 and Option 4, CGP-related 65

Table 4-11. Drinking Water Turbidity Under the Baseline Scenario and Reduction of Drinking Water Turbidity Under Option 1 and Option 4 66

Table 4-12. EPA Menu of Stormwater BMPs fo r Construction Activities and the Potential for BMP-Generated Environmental Impacts 71

Table 4-13. Annualized Reductions in Navigable Waterways Dredging 76

Table 4-14. Annualized Reductions in Reservoir Dredging 77

Table 4-15. Annualized Reductions in Drinking Water Treatment Costs 78

Table 4-16. National Results from the MSA-Le vel Affordability Lowest New Home Price Analysis- Price and Household Affordability Effects 79Construction and Development NPDES Ge neral Permit Environmental Assessment

7 1. INTRODUCTION

1.1 BACKGROUND

Unmanaged stormwater discharges from construc tion activities can cause an array of physical, chemical and biological impacts. Pollutants discharged in runoff from construction sites include sediment, turbidity, and nutrients. All of these pollutants are importa nt contributors to water quality impairment nationwide. Sediment, turbidity, a nd nutrients degrade aqua tic ecosystem health, drinking water supplies, and surface water clarity. Sediment deposition also reduces water depth in lakes, reservoirs, and navigational cha nnels, increasing the need for dredging.

The United States Environmental Protection Ag ency (EPA) has regulated the discharge of pollutants from construction and development activities since November 16, 1990, when the Agency established permit application requirements for ‘‘storm water discharges associated with industrial activity.’’ EPA publis hed a final Phase I regulation on September 29, 1990 (55 FR 47990) that established permit application requi rements for “large” construction sites whose activities, either individually or as part of a larger common plan of development or sale, disturb at least five acres of land and have point source di scharges to waters of the US. Phase II of the stormwater program was published on December 8, 1999 and required NPDES permits for discharges from “small” construction sites whose activities, either indi vidually or as part of a larger common plan of development or sale, disturb at least one acre, but less th an five acres (64 FR 68722).

Beginning in 1998, EPA has issued a series of Na tional Pollutant Discharg e Elimination System (NPDES) general permits covering stormwater from construction and development activities (“construction general permits,” or CGPs) for ar eas where EPA is the NPDES permitting authority. EPA reissued the CGP in 2003 and 2008. EPA is re-issuing its CGP to become effective upon expiration of the existing 2008 CGP. Effluent limitations included in the 1998 through 2008 CGPs have been issued based on EPA’s Best Professi onal Judgment (BPJ), which EPA can use as the basis for setting effluent limita tions in cases where national, technology-based effluent limitation guidelines (ELGs) have not been promulgated. However, for the upcoming permit, EPA will be required to incorporate effluent limitations, including new source performance standards (NSPS), that are consistent with the Agency’s fi nal ELGs (74 FR 62995) for the Construction and Development Industry Point Sour ce Category (the “C&D Rule”) , which were promulgated on December 1, 2009, the upcoming CGP will be required to include the C&D rule requirements. The C&D Rule included a regulatory de finition of “new source” and deve loped effluent limitations for new sources (New Source Performance Standards, or NSPS).

Issuance of a “new source” NPDES permit under S ection 402 of the Clean Water Act (CWA) is considered a “federal action” th at is subject to the National En vironmental Policy Act (NEPA), and EPA regulations at 40 CFR 122.29(c) specify that th e issuance of a NPDES permit for a new source is subject to the review provisions under NEPA as set forth at 40 CFR Part 6.Construction and Development NPDES Ge neral Permit Environmental Assessment

8 1.2 SUMMARY OF THE PROPOSED ACTION The Proposed Action is EPA’s issuance of the 2012 CG P. Like previous versions of the CGP, the permit will authorize the discharge of pollutants in stormwater from new and existing sources associated with construction sites greater than one acre where EPA is the permitting authority. EPA’s existing 2008 CGP became effective on June 30, 2008 (see 74 FR 40338), and will expire on February 15, 2012. The 2012 CGP will replace the 2008 CGP as well as the 2003 CGP for construction sites covered under the administratively continued permit.

The proposed new CGP incorporates the requirem ents of the final C&D rule in addition to clarifying a number of administrative, procedural , and technical requirements that are carried forward from the 2008 CGP. The proposed CGP closed for public comment on July 11, 2011. A summary of the major changes in the proposed 2012 permit, compared to the 2008 CGP, are as follows.

1.2.1 S TRUCTURE /A PPEARANCE OF P ERMIT EPA attempted to restructure its CGP so that it w ould be better organized to present requirements in a generally more readable manner. It is EPA’s h ope that this structure will enhance the permittees’ understanding of and compliance with the permit’s requirements. For instance, the permit’s stormwater control requirements are organized into distinct and related cate gories, such as erosion and sediment control requirements, stabili zation requirements, and pollution prevention requirements.

1.2.2 E LIGIBILITY FOR C OVERAGE Geographic Coverage of the Proposed Permit. Changes to the permit’s ar ea of coverage consists of: Indian Country lands in EPA Region 4 and De nali National Park and Preserve (EPA Region 10) will be added to the proposed permit’s area of coverage and construction sites within the State of Alaska will no longer be covere d under EPA’s CGP due to the authorization of the State NPDES
program.

Categories of Facilities That Ca n Be Covered Under This Permit. The proposed permit will authorize stormwater discharges as sociated with construction sites lo cated in the coverage area of the permit that disturb one or more acres of land, or will disturb less than one acre, but are part of a common plan of development or sale that will ultima tely disturb one acre or more. Eligibility for coverage by the permit is available to the following:

 New projects

 Existing projects

 New operators of new or existing projects, and

 Operators of emergency-related projects.

Eligibility for Emergency- Related Construction. The proposed permit would provide immediate authorization for construction activities required for response to public emergencies (e.g., natural disasters such as a tornado or hurricane, widespread disruptions in essential public services). Immediate authorization will enable work that is necessary to avoid imminent endangerment to human health, public safety, or th e environment, or to reestablis h essential public services, toConstruction and Development NPDES Ge neral Permit Environmental Assessment

9 proceed without administrative delay. The construc tion operator would still need to comply with the terms of the permit, and mu st submit an NOI and develop a stormwater pollution prevention plan (SWPPP) within a set period of time after commencing earth-disturbing activities, whereas typically operators are required to submit NOIs pr ior to commencing earth-disturbing activities.

Treatment Chemicals

. Treatment chemicals must be used in conjunction with conventional erosion and sediment controls to minimize relian ce on its use. Options for the use of cationic treatment chemicals under the CGP were considered such as requiring an individual permit, or including additional, site-specific controls that may apply. In the proposed permit, EPA contemplates prohibiting the discha rge of cationic chemicals, esta blishing maximum dosage rates, and, if the operator intends to use chitosan, re sidual testing requirement s. EPA could provide coverage under the CGP for the us e of cationic treatment chemicals, or, if it was determined that site-specific considerations and the toxicity concerns associated with some polymers warrant, the Agency could require coverage under an individual NPDES permit. Under either the CGP or an individual permit, EPA anticipates that the requirements affecting the use and storage of cationic treatment chemicals would be the same.

1.2.3 N OTIFICATION CHANGES

Authorization Process/ Notice of Intents (NOIs)

. EPA proposes to increa se the “waiting period” for construction site operators seeking coverage under this permit. The new timeframe is intended to better reflect the endangered sp ecies-related reviews that must ta ke place prior to authorization. EPA is also hoping to maximize the use of its el ectronic NOI, or eNOI, process for authorizing construction discharges by requiri ng that construction operators seek coverage using the eNOI system. Certain case-by-case exceptions, i.e., in stances in which a “paper NOI” will be allowed, will still exist, but approval by the appli cable EPA Region will be necessary first.

Notice of Termination. The proposed permit consists of a dditional requirements that affect termination of coverage under the CGP beyond site stabilization, such as removal of temporary stormwater controls and construction mate rials, waste, and wa ste handling devices.

1.2.4 N ON -N UMERIC R EQUIREMENTS C HANGES

Sediment and Erosion Controls

. The proposed permit includes specific requirements that implement the C&D rule’s sediment and erosion control limits. While many of these requirements are already included in the 2008 CGP, the proposed permit includes more detail in order to properly implement the C&D rule. The proposed permit ha s specific requirements that implement the C&D rule’s sediment and erosion control limits. Wh ile many of these requirements are in the 2008 CGP, the proposed permit provides additi onal specifics to properly implement the C&D rule. The most significant requirements in the renewed 2012 CGP will be:

 Installation of vegetative buffe rs or equivalent controls,

 Installation of sediment controls prior to ea rth-disturbing activities,

 General maintenance requirements

 Perimeter controls,

 Exit point stabilization,Construction and Development NPDES Ge neral Permit Environmental Assessment

10  Storm drain inlet control installation and maintenance,

 Additional requirements for use of chemical treatments, and

 Dewatering practice controls and discharge restrictions.

Stabilization Requirements. The proposed permit modifies stab ilization requirements that define more specifically EPA’s criteria for temporary and final vegetative and non-ve getative stabilization.

Pollution Prevention

. Beyond the C&D rule requirements for pollution prevention and the prohibition of certain discharges , the proposed permit contains sp ecific control requirements that ensure pollutant dischargers are eliminated or minimized. The pollution prevention requirements restrict the discharge of fert ilizers at construction sites.

Water Quality-Based Effluent Limits

. The proposed permit specifies additional requirements that apply to sites discharging to wa ters impaired for pollutants commonl y associated with construction activities, such as sediment and nutrients. A dditional requirements include tighter stabilization deadlines and more frequent si te inspections. The proposed permit also includes additional requirements for waters identified as Tier 2, Tier 2.5, or Tier 3 for antidegradation purposes.

Site Inspections. EPA proposes to explicitly require operato rs to visually assess the quality of the discharge if the site inspection occurs during a discharge-generating rain event (e.g. color, odor, floating, settled, or suspended solids). EPA also propos es to modify the storm size that triggers site inspections for those sites that el ect to conduct inspections on a bi -weekly basis from 0.5 inches to 0.25 inches.

Corrective Actions. Although the 2008 CGP required corrective action, it did not include specific requirements instructing the permittee as to what c onditions trigger specific corrective actions and what deadlines apply. The proposed permit speci fies triggering conditions for corrective action, deadlines for such corrective actions, and docum entation of what corrective action(s) were performed.

Stormwater Pollution Prevention Plans (SWPPP). The SWPPP requirements are modified in accordance with the changes discussed above. In ge neral, the requirements are more specific, but consistent with the 2008 CGP.

1.3 CLEAN WATER ACT, NPDES GE NERAL PERMITS, AND EFFLUENT LIMITATION GUIDELINES

Section 301 of the Clean Water Ac t (CWA) provides that the discha rge of pollutants is unlawful except in accordance with an NPDES permit. The Water Quality Act of 1987 added a section to the CWA that directed EPA to develop a phased appro ach to regulate stormwater discharges under the NPDES program. EPA published its final Phase I regulation on November 16, 1990 (55 FR 47990) that established permit applica tion requirements for ‘‘storm wate r discharges associated with industrial activity.’’ EPA comprehensively defined “indu strial activity,” which covered discharges from “construction activity,” including cleari ng, grading, or excavating. Phase I regul ated “large” construction activity, covering activities that, either indi vidually or as part of a larger common plan of development or sale, disturb at least five acres of land and have point source discha rges to waters of the US. PhaseConstruction and Development NPDES Ge neral Permit Environmental Assessment

11 II of the stormwater program was published on December 8, 1999 and required NPDES permits for discharges from “small” construction sites, including activities that, either indi vidually or as part of a larger common plan of development or sale, distur b at least one acre, but less than five acres (64 FR 68722). The vast majority of stormwater discharges associated with cons truction activity ar e covered under NPDES general permits. EPA’s regulations authori ze the issuance of general permits to categories of related discharges, such as di scharges from the same type of source in a common geographic area (40 CFR 122.28). EPA, states, and tribes use genera l permits to cover a group of similar dischargers under one permit. General permits simplify the pro cess for dischargers to obtain authorization to discharge, provide permit requirements for any discha rger that files a Notice of Intent (NOI) to be covered, and reduce the administrative workload for NPDES permitting authorities. General permits, including the fact shee t describing the rationale for permit conditions, are issued by NPDES permitting authorities after consider ing public comments on the draft permit. Typically, to obtain author ization to discharge unde r a construction general pe rmit, a discharger (the owner or operator of the construction site, usually a developer, builder, or c ontractor) submits to the permitting authority an NOI to be covered under the general permit. By submitting the NOI, the discharger certifies that it is e ligible for coverage under the genera l permit and that it agrees to the effluent limitations and other conditions in the published general permit. For background, the first NPDES “construction ge neral permit” (CGP) was issued by EPA in February 1998 (63 FR 7858; EPA Region 6 issu ed their final CGP in July 1998, 63 FR 36490). Upon expiration, the “1998 CGP” was repl aced by a single, five-year national 1 CGP, published final in July 2003 (68 FR 39087). The 2003 CGP made a number of administra tive, technical, and procedural changes to the 1998 permit and incorp orated comments received on the draft CGP, published in December 2002. The 2003 CGP expired on June 30, 2008 and was replaced with the 2008 CGP, which was issued for a 2-year term a nd included provisions that were substantially similar to the 2003 CGP. The 2-year 2008 CGP wa s subsequently extended to February 15, 2012 2 ) that included primarily administrative and pr ocedural changes to the 2003 CGP. The 1998, 2003, and 2008 CGPs regulated stormwater discharges from construction activities primarily through “Best Management Practices” (BMPs) and non-nume ric effluent limitations. These permit terms and conditions were based on EPA’s Best Professi onal Judgment (BPJ), which EPA can use as the basis for setting effluent limita tions in cases where national, technology-based effluent limitation guidelines (ELGs) have not been promulgated. NPDES regulations require an NPDES permitting authority (either EPA or a delegated state NPDES program) to incorporate any newly promul gated ELG into applicable NPDES permits. EPA published its final C&D Rule (74 FR 62995) on December 1, 2009. ELGs can include several different types of technology-based pollution control, based on the type of pollutant, the type of source of the discharge, and leve l of control required by the CWA. The highest level of technology-

1 EPA’s CGP provides coverage to areas of the country where EPA is the permitting authority. In the past, EPA Region 4 issued its own CGP, but starting with the new CGP, Region 4 areas will be covered under that permit.
2 On January 28, 2010, EPA extended the term of th e 2008 CGP from June 30, 2010 to June 30, 2011 (75 FR 4554). EPA extended the 2008 CGP to expire on February 15, 2012 to provide the Agency adequate time to finalize the new CGP.Construction and Development NPDES Ge neral Permit Environmental Assessment

12 based pollution controls are Best Available Technology (BAT) for existing sources and a New Source Performance Standard (NSPS) for new sources . NSPS can be the most stringent because the costs of retrofits are greater th an the costs of new installation s — pollution contro l technology that may be too expensive to install in existing sources can be cost-eff ectively installed in new sources. The C&D rule included BMPs c overing erosion and sediment c ontrol measures and pollution prevention practices covering stormwater discha rges from construction sites that commenced construction after February 1, 2010, which is the date upon which the C&D rule became effective. In addition, the C&D rule promulgated a requirement for larger construction sites to meet a numeric turbidity limit, effective August 2011 for sites disturbing 20 acres or more at a time, and February 2014 for sites disturbing 10 acres or more at a time. Subsequent to the promulgation of the C&D rule, EPA received petitions for reconsideration of the numeric turbidity limit, which identified a potential error in its calculation. EPA re-examined the data and concluded that it had improperly inte rpreted the data upon which the numeric limit was based. In January 2011, EPA stayed the provisions of the C&D rule related to the numeric limitation and associated monitoring requireme nts until the Agency has completed a new rulemaking to correct the numeric limitation on turbidity. EPA plans to issue a corrected turbidity limit in a future rulemaking. The proposed permit is directly affected by the st ay. EPA’s proposed permit indicates that if the numeric limit was finalized prior to the issuance of the final CGP, the limit will be included along with associated monitoring and reporting provisions . Because EPA is still in the process of collecting data to support the reca lculation of the numeric turbidit y limit, and therefore it appears that a final numeric turbidity limit will not be availa ble in time to implement in the final permit, it is unlikely that EPA will include a numeric limit and related monitoring and reporting requirements in the final permit. EPA has proposed, however, to implement the remaining portion of the C&D rule that were not affected by the stay of the num eric limit. Based on public comments on the draft permit, EPA made changes to the proposed permit.

1.3.2 D EFINITION OF N EW S OURCE The regulations in 40 CFR Part 122.2 define “new source” as follows: New Source means any building, structure, facilit y or installation from which there is or may be a ‘discharge of pollutants,’ th e construction of which is commenced: (a) After promulgation of standards of perf ormance under section 306 of CWA which are applicable to such sources, or After proposal of standards of performan ce in accordance with section 306 of CWA which are applicable to such source, but only if the standards are promulgated in accordance with section 306 with in 120 days of their proposal. The regulations at 40 CFR 122.29(b)(4) define what constitutes “construction” of a new source, stating that: Construction has commenced if the owner or operator has: (b)(i) Begun, or caused to begin as part of a continuous on site construction program: (A) Any placement assembly, or installa tion of facilities or equipment; or (B) Significant site preparation work; orConstruction and Development NPDES Ge neral Permit Environmental Assessment

13 (b)(ii) Entered into a binding contractual obligation for the purchase of facilities or equipment intended to be used in its operation with a reasonable time. EPA also has the authority to provide specialized definitions of “new source” to particular point source categories (40 CFR 122.29(b) and 401.10). NSPS for the C&D point source category were prom ulgated in the final C&D Rule on December 1, 2009. EPA defined a new source as “any source, whose discharg es are defined in 40 CFR 122.26(b)(14)(x) and 40 CFR 122.26 (b)(15) that commences construction activity after the effective date of this rule.” Under this defini tion, the only construction sites that are not “new sources” are those sites that comm enced construction activity before the effective date of the final rule, which was 60 days after promulgation, or Fe bruary 1, 2010. The proposed permit incorporates this definition of new source: “New source – a construction project that comm enced construction activities after February 1, 2010, and that requires NPDES permit coverage for its construction discharges under Part 1.2 [of the CGP].”

1.4 PURPOSE AND NEED FOR THE PROPOSED ACTION The purpose of the proposed action — the issuance of the NPDES general permit for stormwater discharges associated with construction sites greater than an acre where EPA is the permitting authority (the construction general permit, or CGP) — is to replace the existing NPDES general permit whose limits, terms, and conditions are base d on BPJ effluent limitations with a new permit that is based on BAT-based effluent limits that are consistent with the C&D rule requirements for new and existing sources. The proposed action is needed because under NPDES regulations, EPA is required to incorporate technology- based effluent limitation guideline s (ELGs) into NPDES permits upon their promulgation. The existing permit was issu ed in 2008; since its issuance, final BAT and NSPS ELGs covering construction and develo pment activities were published in 2009. Consequently, EPA must incorporate thes e new requirements into the CGP.

1.5 DOCUMENTS INCORPO RATED BY REFERENCE Documents that are incorporated by reference in clude the three major t echnical support documents for the C&D Rule; the Preamble and Proposed New CGP and the Fact Sheet to the Proposed new CGP; and the technical support documents for the revision to the numeric limit for final BAT and NSPS ELGs, the Preamble to the revised numeric limits, and the final numeric ELGs for C&D operations. Throughout this EA these doc uments are referenced as follows: EPA 2009a. Development Document for Proposed E ffluent Guidelines and Standards for the Construction and Development Cate gory. November 2009. EPA-821-R-08-007. EPA 2009b. Environmental Impact and Benefits Assessment for Final Effluent Guidelines and Standards for the Construction and Devel opment Category. November 2009. EPA-821-R09-012 EPA 2009c. Economic Analysis of Proposed Effl uent Guidelines and Standards for the Construction & Development Industry. November 23, 2009. EPA-821-R-08-008.

EPA 2011a. CGP

EPA 2011b. CGP Fact SheetConstruction and Development NPDES Ge neral Permit Environmental Assessment

14 EPA 2011c. Final BAT and NSPS Numeric Effluent Limitation Guidelines for the Construction and Development Industry Point Source CategoryConstruction and Development NPDES Ge neral Permit Environmental Assessment

15 2. ALTERNATIVES

2.1 BACKGROUND Congress passed the Federal Water Pollution Contro l Act of 1972, or Clean Water Act (CWA) with the stated objectives of restori ng and maintaining the chemical, phys ical, and biological integrity of the Nation's waters [33 USC 1251(a)] and of atta ining ‘water quality which provides for the protection and propagation of fish, shellfish a nd wildlife [33 USC 1251(a )(2)]. The CWA provides that “the discharge of any pollutant by any pers on shall be unlawful” except in compliance with other provisions of the statute [CWA Section 301(a)]. EPA is aut horized under the CWA to control discharges through the issuance of NPDES permits. NPDES permits are required under Section 402(a)(1) of the CWA to include conditions for meeting technology-based effluent limits established und er CWA Section 301 and where applicable, under Section 306. When technology-based effluent lim itations guidelines ( ELGs) or new source performance standards (NSPS) are promulgated, EPA must incorporate these technology-based limits into applicable NPDES permits [40 CFR 122.44(a)(1)]. Prior to promulgation of final ELGs or NSPS, permitting authorities base technology-b ased effluent limitations on best professional judgment (BPJ) [CWA Section 402(a)(1)(B); 40 CFR 125.3(a)(2)(ii)(B)]. Where technology-based effluent limitations are insufficient for the discharg e to meet applicable wa ter quality standards, NPDES permits must also contain water quality-ba sed effluent limitations as necessary to meet those standards. The technology-based effluent limits in the existi ng 2008 CGP are based on EPA’s BPJ since, at the time of permit issuance, the C&D Rule had not b een promulgated. However in December of 2009, EPA promulgated final ELGs and NSPS coveri ng the construction and development industry, which included a numeric effluent limitation for tu rbidity and defined the e ffective date of NSPSs as February 1, 2010. Upon promulgation of the fi nal C&D Rule, all subsequent NPDES permits must incorporate these technology based limita tions and standards. Thus, the proposed CGP includes the limitations of the C&D Rule to comply with the CWA and NPDES regulations. 3

2.2 PROPOSED ACTION AND ALTERNAT IVES CONSIDERED FOR REVIEW The purpose of this Environmental Assessment (EA) is to analyze, document and make public the potential direct, indirect, and cumulative environmental impacts that may arise from the implementation of the Proposed Action or the No Action alternative considered by EPA in the issuance of a new source NPDES general permit. The scope of this EA is limited to the environmental resources that may be affected by the No Action Alternative or the Proposed Action. Thus, the scope of this EA is limited both geographi cally to those coverage areas specified in the CGP (i.e., in which EPA is the permitting author ity for the stormwater general permit), and categorically to cover only new sources.

2.2.1 N O A CTION A LTERNATIVE : N O NPDES C ONSTRUCTION G ENERAL P ERMIT
ISSUED

3 One provision in the C&D Rule — the numeric standard for turbidity — has been stayed following judicial review. EPA is currently in the process of collecting data to recalculate a new numeric standard.Construction and Development NPDES Ge neral Permit Environmental Assessment

16 The “No Action” alternative would be to not issue a general permit to replace the expiring CGP. Normally, in a case such as this , the Agency uses its authority under the NPDES regulations to administratively continue the existing permit. Pe rmittees that have coverage under a valid NPDES permit at the time of its expiration may maintain their authorization to discharge under the terms and conditions of the expired permit. This author ity to administratively continue NPDES permits works satisfactorily for permittees who have continuing operations at a defined location or within a defined area. However, the authorization to continue to discharge will not extend to facilities or operations that were not covered at the time the valid permit expired. Therefore, only stormwater discharges at C&D sites that were covered under the 2008 CGP as of midnight, February 15, 2012 would continue to be covered until site activities are terminated, at which time their authorization to discharge under the 2008 CG P would also be terminated. Any st ormwater discharges at C&D sites that are not covered as of midnight, February 15, 2012 will require coverage under another NPDES permit.

The C&D Rule has established C&D activity commencing after Fe bruary 11, 2010 as a new source. Unlike most operations covered under NPDES permits , which are generally continuing operations at a single site or within a defi ned circumscribed area, C&D activiti es are generally relatively shortlived (less than a year). As s ite operations that began prior to February 11, 2010 and are still ongoing become completed, the number of C&D ope rations considered existing sources will continue to diminish. EPA’s NOI data for C&D activities indicate that sites considered “existing sources,” (i.e., those where site activity began prior to the February 11, 2010 new source effective date, is covered under the existing CGP, and for wh ich coverage is scheduled to expire after the anticipated effective date of the proposed CGP of February 15 , 2012) will start small and diminish rapidly. At the end of the first year of the pr oposed CGP, the number of existing sources is projected to constitute 3% to 5% of annual CGP activity; by the e xpiration of the proposed permit, less than 1% of annual CGP activ ity will be existing sources ( Table 2-1 ) Table 2-1. Projected Existing Source CGP-Covered Sites Over the Term of the Proposed CGP

Year Projected Number of Existing Sources (a) Low Activity Projection (b) Mean Activity Projection High Activity Projection

2013 286 8% 5% 4% 2014 193 5% 3% 3% 2015 109 3% 2% 1% 2016 65 2% 1% 1% 2017 50 1% 1% 1% (a) Based on data retrieved from EPA’s NOI database on May 23, 2011; sites whose coverage began prior to 02/11/10 and scheduled to expire after 02/15/12. (b) Based on data retrieved from EPA’s NOI database on May 23, 2011; the low activity projection is the minimum annual number of CGP covered sites from 2004 through 2011 (2011, estimated at 3,800); the mean activity projection of 5,846 CGP covered sites is based on the annual number of covered sites from 2004 through 2010 and the estimated number for 2011; the high activity projection is the maximum annual number of 7,316 CGP covered based on the annual number of covered sites from 2004 through 2010 and the estimated number for 2011 Thus, by January 31, 2012, nearly all C&D activities would be ineligible for coverage under an administratively continued 2008 CGP, meaning that operators at virtually all C&D sites would be required to apply for coverage under individual NPDES permits. Based on data from 2004 through 2011, the No Action Alternative would result in submission of approximately 4,000 to 7,000Construction and Development NPDES Ge neral Permit Environmental Assessment

17 individual permit applications annually. These individual permits would include essentially the same terms, conditions, and limitations found in the proposed CGP as discussed under the Proposed Action. Thus, the environmental benefits and costs to the regulated industry would not be improved under this alternative. However, the increas ed effort and uncertainti es of this alternative on the part of both the C&D industry and EPA would be enormous, especially because at present, EPA’s NOI website is processing the thousands of annual notifica tions efficiently. The industry would need to commit far greater resources to preparing applications, and EPA would need to commit far greater resources to reviewing these a pplications, preparing and publishing draft permits for public review and comment, and responding to comments before issuing final individual permits. Industry would have no clear idea of when their permits would be finalized, and project schedules would be at considerable risk. Hypothetically, a potential benef it under an individual permit pr ogram would be the increased opportunity for public review and comment for each permitted site. EPA believes, however, that any advantage to the public re sulting from individualized pub lic and comment opportunities would be outweighed by the negative impacts that would re sult from the delays in the permitting process that EPA anticipates would result. Based on the above discussion of the additional administrative burden and lack of additional environmental benef it, the alternative of not issuing the CGP would render the permitting of construction sites impracticable. EPA provided for notice and comment for the proposed CGP issued on April 25, 2011. Therefore, the public is already given a s ubstantive opportunity to provide comments on the draft permit conditions that will be required of construction sites, which is sim ilar to the type of opportunity they would have under an individual permit. The effluent limits in th e permit, based as they are on the C&D Rule requirements, have also been subject to prior notice and comment during the promulgation of the C&D Rule. After the genera l permit is issued, the public can track the coverage of individual sites by monitoring the electronic Notice of Intent (eNOI) website and have the ability during the authorizati on waiting period to provide comm ents to EPA for consideration.

2.2.2 P ROPOSED ACTION : I SSUE A R EVISED NPDES G ENERAL P ERMIT The Alternative of issuing a revised CGP that incorporates the requirements of the C&D Rule complies with the statutory requirements of the CWA and the requirements of the NPDES regulations. The Agency has promulgated fi nal ELGs and NSPS for the Construction and Development Industry Point Source Category in the C&D Rule. Ther efore, EPA must incorporate the requirements of the C&D Rule 4 into any issued permit covering C&D activities where EPA is the permitting authority. This includes four st ates (Idaho, Massachusetts, New Hampshire, and New Mexico), the District of Columb ia, Puerto Rico, all other U.S. territories with the exception of the Virgin Islands, federa l facilities in four st ates (Colorado, Delaware, Vermont, and Washington),

4 EPA’s proposed permit indicates that if the numeric limit was finalized prior to the issuance of the final CGP, the limit will be incl uded along with associated monito ring and reporting provisions. Because EPA is still in the process of collecting data to support the recalculation of the numeric turbidity limit, and therefore it appears that a fi nal numeric turbidity limit will not be available in time to implement in the final permit, it is un likely that EPA will include a numeric limit and related monitoring and re porting requirements in the final permit.Construction and Development NPDES Ge neral Permit Environmental Assessment

18 most Indian lands and a couple of other specifically designated activ ities in specific states (e.g., oil and gas activities in Texas and Oklahoma). This requirement also applies to any permit issued by a state with delegated general permit au thority for an NPDES permit program.

2.2.3 D ESCRIPTION OF THE P ROPOSED A CTION : I SSUE A R EVISED NPDES G ENERAL P ERMIT The proposed CGP requires operators at eligible construction sites to comply with the final ELG and NSPS requirements found at 40 CFR Part 450. Th e proposed CGP includes effluent limits that fall into four basic categories: erosion and sediment control; st abilization requirements; pollution prevention requirements; and water quality-based effluent limits. The fo llowing is a summarization of these effluent limitations.

2.2.3.1 Non-numeric Effluent Limita tions in the Proposed CGP The non-numeric effluent limitation requirements ar e technology-based and apply to all discharges from construction activities eligib le for coverage under this permit. They are organized in three major sections:

• Erosion and Sediment Control;

• Site Stabilization; and

• Pollution Prevention.

The proposed non-numeric effluent li mits require operators to “fir st prevent the discharges of sediment and other pollutants thr ough the use of effective planni ng and erosion control measures; and second, to control discharges that do occur through the use of effective sediment control measures.” See C&D rule at 74 Fed. Reg. 63016 (December 1, 2009). The effluent limits also require the permittee to implement a range of pol lution prevention measures to limit or prevent discharges of other types of non-sediment discharges.
2.2.3.1.2 Erosion and Sediment Control Requirements The proposed CGP require operators to design, install, and maintain erosion and sediment controls that minimize the discharge of pollutants from earth-disturbing activities. In order the accomplish this, operators must take into account certain design, installation and maintenance considerations when implementing stormwater controls at their site.

Design considerations incl ude the site’s soil and precipitation ch aracteristics and the nature of the stormwater run-off and run-on. Th e operator is also required to direct non-concentrated or nonchannelized discharges from stor mwater controls to vegetated ar eas of the site, including any naturally vegetated buffers establis hed, unless infeasible. Installati on of stormwater controls must be completed prior to each pha se of earth-disturbance, and op erators must use good engineering practices and follow manufacturer’s specifications. Operators are required to keep stormwater controls in effective operating c ondition; frequent inspections ar e required including implementing and documenting correctiv e actions immediately if problems occur. Examples are summarized in Table 2-2

.Construction and Development NPDES Ge neral Permit Environmental Assessment

19 Table 2-2. Proposed CGP Erosion and Sediment Control Requirements

 Sites with surface waters located on or immedi ately adjacent to the property must provide and maintain a naturally vegetated 50-foot buffer between the area of earth disturbance and any surface water or install controls that achieve a sediment load reduction that is equivalent to that of a 50-foot buffer. Th e proposed permit includes a buffer guidance to assist operators in complying with this requirement.

 Sediment controls must be in stalled around perimeter areas of your site that will receive stormwater from earth disturbing activities; sediment must be removed before it has accumulated to a height of one-third of perimeter controls.

 Minimize track-out of sediment from site exit points through use of appropriate stabilization techniques.

 Minimize the disturbance of steep slopes and pr eserve native topsoil, unless infeasible; if infeasible, divert flows around steep slope di sturbances and use sp ecialized controls.

 Controls must address both total volume and peak flow rates; discharges must be directed to vegetated areas; and non-stormwater must be directed to sedime nt control features.

 Sediment must be managed appropriately as specified (e.g., do not wash sediment into stormwater conveyances, storm sewer inlets, or waters of the U.S.; control discharges from sediment or soil piles; minimize gene rating and offsite tracking of dust; minimize soil compaction).

 Conveyance channels must be designed to a void disturbed areas; conc entrated flows must be diverted both within and fr om disturbed soils to prevent further erosion, with special attention to reducing velocity.

 Controls must be established to remove sedi ment before entering any storm drain inlets on the site.

 Dewatering is only permitted from site accumu lations if sediment controls/filters have been successfully administered and discharg ed in compliance with permit requirements for water, sediment, and oil and grease or other pollutants.

 Treatment chemicals must be used in conjunc tion with conventional erosion and sediment controls to minimize reliance on its use. Us e must comply with dosing specifications as well as good engineering and storage practices. Additional, site-specific controls would apply to the use of cationic treatment chem icals than to other types of chemicals. 5

5 In the proposed permit, EPA contemplates pr ohibiting the discharge of cationic chemicals, establishing maximum dosage rates, and, if the oper ator intends to use chit osan, residual testing requirements. EPA could provide coverage unde r the CGP for the use of cationic treatmentConstruction and Development NPDES Ge neral Permit Environmental Assessment

20 2.2.3.1.3 Stabilization Requirements Stabilization refers to coveri ng ground exposed through the constr uction process to reduce erosion and sedimentation. Stabilization may be temporary or final. Temporary stabilization refers to covering exposed soil in areas until final stabiliza tion can be achieved or until the area is disturbed again in the future. Final stabilization refers to using practices to provide permanent cover (either vegetative or non-vegetative) of exposed portions of the site and qualifie s the site for permit termination. Temporary and final stabilization can be achieved through the use of vegetative cover and non-vegetative cover (e.g., hydromulch, erosi on control blankets, riprap) methods. For vegetative stabilization, the propos ed permit requires the operator to provide uniform vegetation that covers 70% or more of the area that was co vered by native vegetation prior to the commencing of construction activities. Non-vegetative cover for temporary and final stabilization must provide effective stabilization of expos ed portions of the site.

The following are the proposed deadlines for initiating and completing stabilization:

 Immediately initiate stabilization if construc tion activities in areas of the site have permanently or temporarily ceased for 14 or more days, and complete within 14 days after the temporary or permanent cessati on of earth-disturbi ng activities.

 Operators discharging to sensitive waters (i .e., impaired for sediment or nutrients, or designated as Tier 2, 2.5, or 3 for antidegr adation purposes) are re quired to complete certain stabilization activities in half the time of sites not discharg ing to such waters.

 Sites in arid and semi-arid areas are provide d with greater flexibility in consideration of the unique climatic and soil conditions that are prevalent in these areas.

2.2.3.1.4 Pollution Prevention Requirements The proposed CGP contains pollution prevention st andards that prohibit ce rtain pollutants from being discharged from constructi on sites including wastewater from concrete washout, fuels and oils, soaps/solvents used in ve hicle washing, and toxic or hazardous substances from a spill. The proposed CGP restricts five types of pollutant-generat ing activities:

 Fueling and maintenance of equipment and vehicle;

 Washing of equipment and vehicles;

 Staging and storage areas for building materials, equipment, and vehicles;

 Washing of containers used for paint, concrete, and other materials; and

 Storage, handling, and disposal of construction waste.

chemicals, or, if it was determined that site-sp ecific considerations and the toxicity concerns associated with some polymers warrant, the Agen cy could require coverage under an individual NPDES permit. Under either the CGP or an individual permit, EPA anticipates that the requirements affecting the use and storage of ca tionic treatment chemicals would be the same.Construction and Development NPDES Ge neral Permit Environmental Assessment

21 If an operator will conduct fueling and/or maintena nce of equipment or vehi cles at the site, an effective means must be provided to eliminate the discharge of spilled or leaked chemicals from the area designated for this activity

. This includes immediate cleanup of contaminated surfaces and elimination of the source of the spill using adequate supplies to handle spills, leaks, and disposal of liquids. Requirements also include using dry clean up measures where possible and not cleaning surfaces by hosing the area down. A dditionally, operators must provide an effective means of minimizing the discharge of pollutants from e quipment and vehicle washing and eliminate the discharge of soaps, detergents, or solven ts used in vehicle and equipment washing.

Exposure of products, materials, or wa stes stored at the site to stor mwater, except for those that are either not a source of contamination to stormwater or are designed to be exposed to stormwater, must be minimized. Operators must provide co ver or similarly effective means to prevent discharges. Additional requirement s are implemented for storage of particular products, materials or wastes such as pesticides, fuel, oil, hydraulic fluids, hazardous waste and domestic waste. These products must be stored in seal ed, water-tight containers away from exposure to stormwater and operators must use dry methods of cleanup where po ssible in conjunction with proper disposal.

Where operators will use paint or concrete or co nduct other washout activities on site, they must provide an effective means of eliminating the discharge of water from these activities. To comply with this requirement, washout or cleanout activities must be located as far away as possible from surface waters and stormwater inlets or conveyance and all washwater must be directed into a leakproof container or leak-proof pit. The container or pit must be designed so that no overflows can occur due to inadequate sizing or precipitation. Additionally, all washout or cleanout wastes must not be dumped in storm sewers and hardened conc rete wastes must be removed and disposed of consistent with construction waste provisions. The proposed CGP also requires immediate cleanups of spills, emergency sp ill notification and reporting requi rements for toxic or hazardous substance spills, and restricti ons on fertilizers containing nitr ogen or phosphorus except for compost, manure, or other natural fertilizers.

2.2.3.1.5 Best Management Practices (BMPs) to Achieve Non-Numeric Effluent Limitations

Construction site operators comply with the pr oposed CGP through the implementation of a variety of BMPs, which minimize the discharge of pollutant s from construction site stormwater discharges when selected, implemented, and managed as requi red. The proposed permit does not dictate that any specific BMP be installed on a site; constructi on site operators have th e discretion of choosing the BMPs that meet the requirements of the permit a nd of their project. A mo re detailed discussion of the common BMPs used on construction sites and effectiveness data is in cluded in Section 4.3.

BMPs selected by construction operators to comply with the proposed permit fall into five general categories:

 Construction Site Planning and Management

 Erosion Control

 Runoff Control

 Sediment ControlConstruction and Development NPDES Ge neral Permit Environmental Assessment

22  Good Housekeeping/Materials Management

Construction Site Planning and Management BMPs emphasize the importance of construction sequencing in the specified work schedule to co ordinate the timing of land-disturbance and the installation of erosion and sediment control measures. The reduction of on-site erosion and off-site sedimentation by performing land-di sturbing activities and installi ng erosion and sediment control practices in accordance with a plan ned schedule is the goal of the BMP (Smolen et al., 1988). The BMP includes self-inspection and maintenance pr ograms to ensure that the BMP is functioning properly to prevent pollution di scharges. Awareness and educati on of general so il and sediment controls through this BMP expedites the repair and maintenance e fforts by raising i ssues early. The BMP promotes the preservation of natural vegetati on (existing trees, vines, brushes, and grasses) when possible to provide water quality benefits by in tercepting rainfall, filt ering stormwater runoff, and preventing sediments and other polluta nts from leaving the site (USEPA 2011a).

Construction Site Planning and Management BM Ps also emphasize the minimization of clearing and grading activities. The intent of this BMP is to manage the terrestrial activities to ensure the protection of waterways through a phased construc tion approach that limits soil exposure. Soils that are exposed are intended to be immediately stabilized. The pr otection of steep slopes and cuts; the installation of perimeter controls to filter se diments; and the use of advanced sediment settling controls are physical measures desc ribed in this BMP category to mi nimize terrestrial impacts. The control of waste at the construc tion site along with site inspecti ons and maintenance of the BMP minimizes terrestrial impacts (USEPA 2011).

Erosion Control Measure BMPs identify the phys ical and chemical measures that can be implemented on a site to control erosion. Fourteen specific control measures are identified in this BMP category:

 Compost Blankets  Sodding

 Dust Control  Soil Retention

 Geotextiles  Soil Roughening

 Gradient Terraces  Temporary Slope Drain

 Mulching  Temporary Stream Crossings

 Riprap  Wind and Sand Fences

 Seeding  Chemical Stabilization

When selected and implemented as designed, thes e control measures minimize the discharge of sediment by controlli ng erosion on sites.

Runoff Control BMPs emphasize the implementation of rock check dams, grass-lined channels, slope diversion channels, and temporary diversion dikes to control runoff. Rock check dams are recommended for long channels. Check dams are mo st effective when used in a series, creating multiple barriers to sediment-laden runoff. Rock check dams are more effective than silt fences or straw bales to stabilize wet-weather ditches. Grass-lined channels can effectively transport stormwater from construction areas if they are designed for expected flow rates and velocities and if they do not receive sediment directly from di sturbed areas. Permanent slope diversions are designed to transport runoff down a slope in a ma nner that minimizes the potential for erosion.Construction and Development NPDES Ge neral Permit Environmental Assessment

23 Diversions can be constructed by creating channels laterally ac ross slopes to intercept the downslope flow of runoff. The cha nnels have a supporting earthen ri dge on the bottom sides to reduce slope length, collect stormwater runoff, and deflect the runoff to outlets that convey it without causing erosion. When properly placed and maintain ed, earth dikes used as temporary diversions can control the velocity and direc tion of stormwater runoff. Used by themselves, they do not have any pollutant removal capability. They must be us ed with an appropriate sediment-trapping device at the outfall of the diversion channel. Thes e runoff control BMPS are designed to minimize impacts by controlling runoff (USEPA 2011).

Sediment Control BMPs identify the physical meas ures and devices that can be implemented on a site to control sediment. Thirteen specific cont rol measures are identified in this BMP category:

 Brush barrier  Sediment filters and sediment chambers

 Compost filter berms  Sediment traps

 Compost filter socks  Silt fences

 Construction entrances  Storm drain inlet protection

 Fiber rolls  Straw or hay bales

 Filter berms  Vegetated buffers

 Sediment basins and rock dams

When selected and implemented as designed, these c ontrol measures minimize the impacts to the quality of the discharge by c ontrolling sediment on sites.

Good Housekeeping/ Materials Management BMPs address concrete washout, building materials/site waste, spill prevention/control plan s, and vehicle maintenance/washing activities. Concrete washout BMPs are used to contain concrete and liquids when the chutes of concrete mixers and hoppers of concrete pumps are rins ed out after delivery. The washout facilities consolidate solids for easier dis posal and prevent runoff of liquids . The wash water is alkaline and contains high levels of chromium, which can leach into the ground and contaminate groundwater. It can also migrate to a storm dr ain, which can increase the pH of ar ea waters and harm aquatic life. Solids that are improperly disposed of can cl og storm drain pipes and cause flooding. Installing concrete washout facilities not onl y prevents pollution but also is a matter of good housekeeping at the construction site (USEPA 2011).

Building materials and other constr uction site wastes must be properly managed and disposed of to reduce the risk of pollution from ma terials such as surplus or refuse building materials or hazardous wastes. Practices such as trash disposal, recycl ing, proper material handling, and spill prevention and cleanup measures can reduce the potential for stormwater runoff to m obilize construction site wastes and contaminate surface or ground water. Waste management practices are effective only when they are regularly practiced at a construction site. In storage and use areas, it is recommended to post the guidelines for proper handling, storage, and disposal of constr uction site wastes; the training of workers is recommended in these pract ices to ensure that everyone is knowledgeable enough to participate (USEPA 2011).

Spill Prevention and Control Plans (SPCP) clearly state measures to stop the source of a spill, contain the spill, clean up the spill, dispose of contaminated materials, and train personnel toConstruction and Development NPDES Ge neral Permit Environmental Assessment

24 prevent and control future spills. An SPCP can be highly effective at reducing the risk of surface and ground water contamination; however, to ensure that procedures are followed, a construction site operator should provide wo rker training, appropriate materi als and equipment for cleanup, and adequate staff time (USEPA 2011).

Vehicle maintenance and washing occurs in garage s and wash facilities, not on active construction sites. However, if thes e activities must occur on site, operators should foll ow appropriate BMPs to prevent untreated nutrient -enriched wastewater or hazardous wastes from being discharged to surface or ground waters. These techniques effectiv ely reduce discharges of untreated automotive wastes and wash water to receiving waters. Their effectiveness highly depends on personnel's training and level of commitment to follow procedures (USEPA 2011).

BMPs, when selected and implemented as designe d, offer an effective approach in minimizing discharges of pollutants from constr uction site stormw ater discharges.

2.2.3.2 Water Quality

­ Based Effluent Limitations The 2012 CGP includes provisions for meeting wate r quality standards in three categories. One category includes the general effluent limitation to meet applicable water quality standards. The second category includes discharge limitations for impaired waters, defined as those identified on the CWA Section 303(d) list or waters with an EPA-approved or established TMDL. The third category includes the discharge requirements for waters identified by a state, tribe, or EPA as Tier 3 (outstanding national res ource waters) or Tier 2/2.5 waters (h igh quality waters) for the purpose of non-degradation determinations. The proposed pe rmit requires more stringent requirements for sites discharging to impaired or to high-quality waters, including more stringent stabilization deadlines and more frequent si te inspections to supplement the permits non-numeric technology based effluent limits discussed above.
2.2.3.2.2 General Water Quality-based Effluent Limitations Discharges must be controlled to meet applicab le water quality standards, as well as any further state or tribal requirements that are included in the proposed CGP as part of the state or tribe’s CWA Section 401 certification. EPA has made an affirmative determination that, absent any information demonstrating otherwise, compliance with the terms and cond itions of the proposed permit is sufficient to control stormwater discharges to comply with water quality standards. If the operator or EPA become aware that stormwater discharges are not meeting applicable standards, corrective action will be required. EPA may also impose additional wa ter quality-based site-specific requirements or require coverage under an indi vidual permit if information is provided that indicates water quality standards are not met due to insufficiently controlled stormwater discharges from a C&D site covered under the CGP.
2.2.3.2.3 Water Quality-based Discharge Limitations for Impaired Waters A construction site will be considered to discharge to an impaired water if the first water of the U.S. to which it discharges is identifi ed by a state, tribe, or EPA pursuant to Section 303(d) of the CWA as not meeting an applicable water quality st andard, or is included in an EPA-approved or established total maximum daily load (TMDL). Fo r discharges that enter a storm sewer system prior to discharge, the first wate r of the U.S. to which the site discharges is the waterbody thatConstruction and Development NPDES Ge neral Permit Environmental Assessment

25 receives the stormwater discharge from the storm sewer system. If the site discharges to an impaired waterbody, the construction site operator must provide: a li st of all impaired waters, the pollutants causing impairment, and a referen ce to any approved or established TMDL.

If the site discharges to a su rface water that is impaired for sediment or a sediment-related parameter such as total suspended solids (TSS) or turbidity, and/or nutrient s, including impairments for nitrogen and/or phosphorus, the proposed permit requi res the site operator to meet the following additional requirements:

 Comply with any additional state or tribal impairment-related requirements included in the permit.

 Meet deadlines for stabilization that are shorter than for other sites not discharging to such
waters.

 Conduct more frequent site inspections.

The stabilization requirements de scribed above (Section 2.2.3.1.3) ar e superseded by the following requirement for sites discharging to waters impair ed for sediment, sediment -related, or nutrients:

 Immediately begin stabilization when earth-dis turbing activities permanently or temporarily cease for at least 7 calendar days Construction site operators must comply with the following site inspection requirement for sites discharging to waters impaired for se diment, sediment-related, or nutrients:

 Inspect the site at a minimum of once ever y 7 calendar days and within 24 hours of 0.25 inch or greater storm event.
2.2.3.2.4 Water Quality-based Discharge Limitations for Tier 2, 2.5, or 3 Waters A construction site will be considered to discharge to a Tier 3, Tier 2, Tier 2.5, or 3 water if the first water-body to which it discharges is designated as a Tier 3, 2, or 2.5 wa ter. For sites that discharge to a storm sewer system, they would be considered to discharge to a Tier 3, 2, or 2.5 water if the first surface water receiving the discharge from the sewer system is designated as a Tier 3, 2, or 2.5 water. The proposed permit requires construction s ites discharging to these waters to comply with the same requirements as those required of discha rges to sediment or nutrient-impaired waters.

2.2.3.3 Site Inspections and Corrective Actions

Inspections must be conducted by a “qualified pers on”, who is knowledgeable in the principles and practice of erosion and sediment controls, a nd pollution prevention, who possesses the skills to assess conditions at the construc tion site that could impact stor mwater quality, and the skills to assess the effectiveness of any stormwater contro l measures selected to control the quality of stormwater discharges from the construction acti vity. This may be cond ucted by an authorized representative of the EPA, or a nother federal, state, local or tr ibal agency. While the proposed permit establishes the required minimum inspection frequency of once every 7 calendar days or once every 14 days and within 24 ho urs of the occurrence of a storm event of 0.25 inches or greater, increases and decreases in inspections can occu r and are outlined in the permit depending on siteConstruction and Development NPDES Ge neral Permit Environmental Assessment

26 conditions. Inspection frequency in creases for sites that discharg es to a sediment or nutrientimpaired water or to a water that is identified by your state, tribe, or EPA as Tier 2, Tier 2.5, or Tier 3 for antidegradation purposes and decreases for certain arid and semi-arid areas and frozen conditions. Additionally, the proposed permit lays out the required areas and activities to be inspected; including requirements for an inspectio n report to be completed within 24 hours of any site inspection.

Operators must immediately take all reasonable steps to minimize or prevent the discharge of pollutants until a permanent solution and corrective ac tion is installed and made operational, or if applicable, clean up any contaminated surfaces so th at the material will not discharge in subsequent storm events. Within 7 days of discovery, operato rs must institute corrective actions followed by a corrective action report and progress update within one week of impl ementing the corrective action. Any corrective actions required by EPA as a result of a permit violation during inspection must be complied with.

2.2.3.4 Stormwater Pollution Prevention Plan (SWPP) Requirements

In order to gain coverage under the proposed CGP, operators must develop a stormwater pollution prevention plan (SWPPP) prior to submitting their NOI that describes the nature and location of the construction activities, including the physical attributes of the site, a list of pollutants and pollutantgenerating activities occurri ng on the site, certain characteristics of the stormwater discharge, and the people responsible for implementation activities under this permit. Additional information must be included in the SWPPP on the selection, design , installation, and maintenance of stormwater control measures used to control pol lutants in discharges from the site in order to satisfy the effluent limitations in the permit. The SWPPP must in clude documentation of compliance with other federal requirements such as the Endangered Species Act (ESA). SWPPP’s must be available on site or at an easily accessible lo cation so that is can be made av ailable during site inspections and upon request.Construction and Development NPDES Ge neral Permit Environmental Assessment

27 

### 3. AFFECTED ENVIRONMENT

3.1 INTRODUCTION This chapter describes the physical, biological, and socioeconomic resources that may be affected by stormwater discharges from large and small construction activities covered under the proposed 2012 CGP. To satisfy the requirements of 1502.2(b) of CEQ’s NEPA implementing regulations, this EA focuses on resource values potentially subject to impact and critical elements of the human environment unless they are either not present in the affected e nvironment, or present but not affected.

When considering the affected environment, it is necessary to define the geographic scope of the proposed action. Since the proposed action of issuing a revised C onstruction General Permit is only applicable where EPA is the permitting authority, the geographic scope includes four states (Idaho, Massachusetts, New Hampshire, and New Mexico), th e District of Columbia, Puerto Rico, all other U.S. territories with the exception of the Virgin Islands, federal faci lities in four states (Colorado, Delaware, Vermont, and Washington), most Indian la nds and other specifically designated activities in specific states (e.g., oil and gas ac tivities in Texas and Oklahoma).

3.2 PHYSICAL RESOURCES EPA estimates that construction takes place on 8 53,000 acres annually in the continental US and that stormwater discharges from these sites rele ase more than 5 billion pounds of sediment into surface waters (USEPA 2009a). A ll major surface water types rece ive construction discharges, including streams, rivers, wetlands, lakes, estuarie s, and coastal waters. In any given year, some level of construction acti vity occurs in the majority of U.S. watersheds. However, EPA’s review found most construction acreage is c oncentrated in a relatively limite d number of watersheds in any given year. Based on analysis of the watersheds associated w ith more than 62,000 surface water reaches in the conterminous United States, between 1992 and 2001 more than 50% of all C&D activity occurred in less than 5% of U.S. watersheds (USEPA 2007). A common development pattern from this analysis of where C&D activity occurred was th at new construction concentrated in rural and suburban watersheds adjacent to more densely developed urban areas. However, because C&D activity is of a temporary nature , the locations of the most highly impacted watersheds in the US shift over time. Typical construction activities include clearing vegetation; excavating, moving, and compacting earth and rock. Since, soil and sediment are co mposed of organic matter, nutrients such as phosphorus and nitrogen, metals, and other natu ral and synthetic compounds. Many of these components travel with soil particles that have eroded and are discharged to surface waters.

3.2.2 W ATER R ESOURCES EPA used the National Land Cover Dataset (NLCD) to estimate the amount of newly developed land occurring annually in th e continental United Stat es (CONUS) between 1992 and 2001 (USEPA 2009a). By overlaying geographic inform ation system (GIS) layers of states and watersheds with the NLCD data, EPA was able to estimate the annual nu mber of acres of new development at both the state and watershed level between 1992 and 2001. EPA estimated annual development rates between 1992 and 2001 for a pproximately 44,000 watersheds where a net increase in urban land cover was identified. A pproximately 7,800 additional watersheds showedConstruction and Development NPDES Ge neral Permit Environmental Assessment

28 either no change or a minor decrease in urba n land uses between 1992 and 2001 (USEPA 2009a). While stormwater discharges from constructi on activity are generally related to effects on freshwater watersheds, bot h freshwater and marine ecosystems are affected.

3.2.2.1 Freshwater Ecosystems EPA defines a freshwater ecosystem as an aquatic system which contains dr inkable water or water of almost no salt content ( http://www.epa.gov/bioiweb1/aquatic/freshwater.html ). Freshwater resources include streams, rivers, ponds, lake s, reservoirs, wetlands, and groundwater. These freshwater resources provide s ource water for drinking, agricu lture, industry, and sanitation; support recreation, e.g., swimming, fi shing, and boating; and are a source of food, e.g., fish, crustaceans, and shellfish. Lakes, ponds, and reser voirs act as deposition zones (ecological sinks) for sediments. Longer flow residence times also mean that an influx of turbid water can persist for longer periods of time than would occur in stream s or rivers. Residence times vary widely among lakes, ponds, and reservoirs (USEPA 2009b). Table 3-1 indicates general characteristic differences between lakes, ponds and reservoirs. Table 3-1. Some Characteristic Differences between Lakes, Ponds, and Reservoirs

Lakes Ponds Reservoirs
Larger Smaller Varying sizes but usually larger
May have dramatically different temperatures from surface to bottom
waters Top to bottom waters generally have the same temperature Similar to lakes may have dramatically different temperatures from surface to bottom waters
Light generally does not reach bottom at deeper points Light generally will reach the bottom in all areas of the pond Light generally does not reach bottom at deeper points
Generally can only support rooted plants at shoreline Can support rooted plants across the entire pond Generally can only support rooted plants at shoreline
Lakes are natural Ponds are usually man-made Man-made

Can affect local climate if large enough Tend to be greatly affected by local climate Can affect local climate if large enough

Source: EPA 2009b
Lakes are inland bodies of fresh wa ter and can range in size from less than one acre to several thousands of acres. Reservoirs are lakes, often ma n-made, that control water flow for hydroelectric power generation, flood control, a nd/or municipal water supplies. Lakes vary physically in terms of light levels, temp erature, and water curren ts; chemically, in terms of nutrients, major ions, and contaminants; biol ogically, in terms of community structure and function; and dynamically, in terms of bioma ss, population numbers, and growth rates. A fundamental set of properties of lakes is the interaction among light , temperature and wind mixing. The absorption and attenuation of light by the water column control temperature and photosynthesis, which provides food and much of th e dissolved oxygen in the water. Solar radiation is nearly always the major source of heat and is a major factor in the wind pa tterns of the lake basin and lake water movements. Rivers and streams are general terms used to desc ribe bodies of moving wate r. Rivers are larger than streams and empty into larger waterbodies su ch as oceans and lakes. River and stream systemsConstruction and Development NPDES Ge neral Permit Environmental Assessment

29 consist of numerous tributaries. Streams are typica lly identified by their stream order, categorized in three main types:

 Ephemeral streams regularly exist for short pe riods of time, usually during a rainy period, and may have defined channels even when they are dry

 Intermittent streams flow at different times of the year, or seasonally, when there is enough water from rainfall, springs, or other surface s ources such as melting snow or even discharge from a wastewater treatment facility

 Perennial streams are those that flow year-round. Silt and organic materials settle and accumulate in the streambed of slowly flowing rivers and streams. These materials decay and become th e primary food resource for the invertebrates inhabiting the streambed. Nutrient levels and se diment loads often vary throughout the different locations along the course of a mature river/stream and, therefor e, affect velocity and current. Wetlands are natural sediment deposition zones. Water flow volumes and velocities are smaller than in most other surface water types, allowi ng time for settling of sediment from the water column. However, because of lower flow volumes and speeds, influxes of turbid and sedimentladen water also typically remain for a longer peri od of time in a wetland than they do in a stream or river channel. Wetland ecosystem structure is heavily influenced by the type of vegetation the wetland supports, which is influenced by wate r and sediment distribution in the wetland. Sedimentation levels can change the types of ve getation in the wetland, with consequences for the organisms the wetland supports.

3.2.2.2 Marine Ecosystems Marine ecosystems are a part of the largest aqua tic system on the planet, covering over 70% of the Earth's surface. The habitats that make up this system range from highly productive nearshore coastal regions to the relatively barren ocean floor. Some examples of important marine ecosystems

are:

 Oceans

 Estuaries and salt marshes

 Coral reefs and other tropical co mmunities (e.g., mangrove forests)

 Coastal areas like lagoons, kelp and seagrass be ds, and intertidal sy stems (rocky, sandy, and muddy shores). Marine ecosystems are highly diverse, with sp ecies ranging from tiny plan ktonic organisms that form the base of the marine food web (i.e., phytoplankton and zooplankton) to large marine mammals such as whales, manatees, and seals. Nume rous fish species reside in marine ecosystems, and birds, including shorebirds , gulls, wading birds, and tern s, are equally plentiful. Like other aquatic ecosystems, ma rine ecosystems require nutrients and light to produce food and energy and are limiting factors in marine ecosys tem productivity. Like many other aquatic plants, photosynthetic marine organisms rely on sunlight and chlorophyll to produce food and energy. However, light penetration decreases with increasi ng water depth similar to freshwater systems, but given the much greater depths of the oceans, ph otosynthesis can only take place in a very small fraction of ocean waters near th e surface, called the photic zone. Nutrient availability also varies very widely spatially. Nearshore waters, such as estuaries and marshes, are often rich in nutrients, allowing primary production to be very high and to supportConstruction and Development NPDES Ge neral Permit Environmental Assessment

30 diverse and abundant ecological communities. Howe ver, excess nutrient loads can cause an overstimulation of primary production whose decompos ition results in depleted oxygen levels causing eutrophic conditions, or “d ead zones, in coastal and nearshore habitats. Estuaries vary widely in benthi c geometries, residence times, flushing rates, vertical mixing, stratification, wave exposure, and other factor s that govern sediment transport and deposition. When turbid, sediment-laden freshwater decelerat es and encounters tidal cycles in the estuary, a zone forms where the channel discharge and tidal ac tion largely cancel each ot her out, resulting in deposition of suspended sediment (Chapra 1997). Additionally, increasing salinity favors flocculation of fine sediments. As a result, large deltas often form where rivers deposit sediments in coastal waters. Marine ecosystems are very important to the hea lth of both marine and te rrestrial environments. Mangroves, reefs, and seagrass be ds provide physical protection to coastlines; salt marshes and estuaries act as sediment sinks and filter terrestrial runoff; coas tal habitats alone account for approximately one-third of all marine biological productivity. Estuarine ecosystems (i.e., salt marshes, seagrasses, mangrove forests, etc) are among the most biologically productive regions on the planet.

3.2.2.3 Human Use There are many human uses of surface waters such as transportation, reservoirs, drinking water and recreation which should be consider ed. Navigable waterways, includi ng rivers, lakes, bays, harbors, and shipping channels and canals are an integral part of the Na tion’s transportation and commerce infrastructure. The US Army Corps of Engineer s (USACE) operates and maintains 12,000 miles of navigable channels in the US’s inland and intr acoastal waterways; opera tes 192 commercial lock and dam sites; and is responsible for ports and waterways in 41 states (USACE 2009). Reservoirs are water impoundments that provide drinking water, flood control, hydropower supply and recreational opportunities. Th e National Inventory of Dams includes more than 75,000 dams and an estimated 375,000–750,000 additional man-ma de impoundments in the United States (Renwick et al. 2005). Smaller impoundments ar e used for recreation, livestock water supply, sediment trapping and erosion control, and other purposes. There are approximately 155,000 public water systems in the United States. EPA classifies these water systems according to the number of people they serve, the source of their water, and whether they serve the same customers year-round or on an occasional basis (USEPA 2011b). Lastly, a variety of recreational activities take pl ace in or near surface waters including boating; swimming; hunting; and outings to hike, jog, picnic, cam p, and view wildlife.

3.3 BIOLOGICAL RESOURCES The overwhelming majority of dir ect and indirect environmental im pacts resulting from stormwater discharges are felt in the aquati c environment. Therefore, EPA’s discussion is primarily focused on aquatic ecosystems.

3.3.1 A QUATIC V EGETATION AND W ILDLIFE R ESOURCES Freshwater (including both fresh water and estuarine species) and saltwater aquatic organisms share more than the common bond of living in water me dia. Freshwater and marine ecosystems are similar in most aspects, with the most obvious diffe rence in the salinity of the aquatic media they inhabit. From primary producers like algae and seagrasses, to macro-invertebrates, to the topConstruction and Development NPDES Ge neral Permit Environmental Assessment

31 carnivores, freshwater and marine organisms sh are the same ancestry and ecological function s . The marine ecosystem is more biologically diverse, but the species that dominate in shallow coastal waters, estuaries, lakes, and rivers tend to be from the same phylum. Estuarine and marine species that C&D industry-related stormw ater could impact occupy simila r niches and generally perform the same community functions as those found in fr eshwater ecosystems. Organisms within coastal and estuarine ecosystems that ar e biologically similar to their freshwater counterparts include vertebrates (e.g., fish, amphibians, reptiles, bird s, and mammals), invert ebrates (e.g., zooplankton, crustaceans, worms, mollusks), and algae and occupy similar niches in the marine ecosystems as they do in the freshwater environment

. Some major groups of organisms known to inha bit aquatic ecosystems include algae, fungi, bacteria, plants, invertebrates (e.g., protozoan, rotifers, worms, mollusks), and vertebrates (e.g., fish, amphibians, reptiles, birds, and mammals). Inf ectious agents such as viruses are also present. Phytoplankton and zooplankton form the base of the food chain in aquatic environments. Periphyton, macrophytes (aquatic plan ts), insects (although only found in freshwater and estuarine ecosystems), fish, and amphibians are found in both freshwater and marine environments. Various bird species such as ducks, gulls , pelicans, eagles and ospreys also are supported by freshwater and marine systems. Primary producers, including algae, phytoplan kton, submerged aquatic vegetation, and other macrophytes, are found in most aquatic ecosystems. Aquatic ecosystems vary in the degree to which they derive energy and resources from pr imary producers. Some systems (e.g., small streams in forested watersheds) derive a large proportion of their energy from external sources (e.g., leaf debris) (Bilotta and Brazier 2008). Other systems are heavily depe ndent on the productivity of primary producers (e.g., seagrass beds). Aquatic invertebrates, including zooplankton, insects, crustaceans, annelids, are widely distributed among aquatic ecosystems and can be found in even the smallest surface waters. They are filter feeders, suspension feeders, predators and s cavengers. These organisms inhabit the bottom substrates of ponds, lakes, rivers, streams, estuarie s, and nearshore coastal wa ters. They also play a vital role in maintaining sediment and water qual ity. They provide an important link in the aquatic food chain between primary producer s and larger organisms such as amphibians, reptiles, fish, birds, and mammals (Waters 1995). Table 3-2 lists the major classificat ion of aquatic organisms, and common names for species within each classification. The freshwaters of North America are populated by a rich array of native fishes. While names such as trout and bass are well-embedded into the Am erican vernacular, less familiar groups such as darter, madtom, and dace remain relatively unknown. Freshwater fishes comprise eight Orders in the taxonomic classification with over 1,000 species.

The freshwater fishes of North Am erica occupy a variety of habitats , ranging from narrow roadside ditches to large rivers and lakes. The factors that dictate the dist ribution of a particular species include climate, physiography, hydrology, stream size, biogeography, geochemistry, and human disturbance. The last factor has become incr easingly important as a growing human population increases its demands on the natu ral environment (USEPA 2008).

Table 3-2. Common Names of Prevalent Freshwater, Estuarine, and Saltwater OrganismsConstruction and Development NPDES Ge neral Permit Environmental Assessment

32 Classification Freshwater Estuarine/Marine

Algae Diatoms, Stonewarts, Green Algae, Dinoflagettes, Euglenoids Green algae, Blue-green algae, Kelp

Macrophytes Water lily, Pondweed, Wild celery, Water hyacinth, Water lettuce Turtle grass, Eel grass, Widgeon
grass

Invertebrates Mayfly, Stonefly, crawfish, Isopods, Snails, Clams Shrimp, Blue crab , Oysters, Clams

Vertebrates Frogs, Newts, Salamanders, Osprey, Bald eagles, Fishes 1 Green sea Turtles, leatherback turtles, Manatees, Least terns, Pelicans, Fishes

Like freshwater fishes of Nort h America, coastal/estuarine fish es occupy a variety of habitats, ranging from small tidal creeks to open ocean. Th e size of coastal/estuarine fishes ranges from a few millimeters to over three meters. Most are fr ee swimming, live in close relationship with the bottom or burrow into the bottom. They may be he rbivores, carnivores, and/ or scavengers. Coastal and estuarine fishes encompass more than 16 Orders in the taxonomic classification, and like freshwater fishes, range from herbivores to piscivores in tr ophic classification. Nearshore coastal ecosystems are influenced by terre strial activities, such as C&D, through river drainage to rivers, estuaries and bays. Near co astal ecosystems provide recreational and commercial catch far out of proportion to the marine ecosyst em as a whole. The National Marine Fisheries Service (NMFS) reported that 39 % of the commercial fisheries harvest (3.3 billion pounds) was taken within 3 miles of shore. Inland catch (e.g., fishing in sou nds, rivers and/or bays) represented 45% of total marine recreational catch, while 29% of total recreational catch was from shore. NMFS also notes that the top five species either harvested or releasedwere species commonly found within the 0-3 mile zone (NMFS 2009).

3.3.2 T ERRESTRIAL V EGETATION AND W ILDLIFE R ESOURCES Terrestrial ecosystems differ from aquatic ecosy stem by the lower availability and consequent importance of water as a limiting factor. Organisms in a terrestrial ecosystem are adapted to obtain and retain water. Plants of the terrestrial ecosystem include mosse s, liverworts, non-vascular and vascular plants, with the vascular plants provi ding the majority of primary pr oductivity. They range from deep forest to grasslands to desert ecosystems. Terrestrial plants provide nutrient transport and ground cover. They are a valuable food source for wildlife and humans, as well as a source of beauty to our landscape. Invertebrates live in most terrestrial ecosystem and are primarily from two Classes, Insecta and Arachnida, within the Phylum Arthropoda. Inverteb rate adults and larvae are an important food source for much of both aquatic and terrestrial wildlif e. They also can be as much of a nuisance — consuming crops and food stored for human consum ption, as well as serving as vectors for many human pathogens — as they ar e ecologically beneficial. Vertebrates include birds, mammals, reptiles, an d amphibians and are the top consumers of the terrestrial ecosystem. These organisms use both terrestrial and aquatic systems for shelter,Construction and Development NPDES Ge neral Permit Environmental Assessment

33 reproduction and food. Some vertebrates, such as mammals and birds, are mobile, while others, such as reptiles and amphibians, are tied directly and closely to aquatic systems.

3.3.3 T HREATENED & E NDANGERED S PECIES The current U.S. Fish and Wildlife Service (U SFWS) list of threatened and endangered (T&E) species includes 580 animal species and 795 plant species in the U.S. and 1,976 plant and animal species both foreign and domestic (USFWS 2011 a). The National Marine Fisheries Service (NMFS) is responsible for the stewardship of the nation's living marine res ources, anadromous fish, and their habitat. NMFS has jurisdiction ove r 74 listed species (NMFS 2011a). NMFS is responsible for the management, conservation and pr otection of living marine resources within the United States' Exclusive Economic Zone (w ater three to 200 miles offshore). A species is federally listed as “endangered” wh en it is likely to become extinct within the foreseeable future throughout all or part of its range if no immediate action is taken to protect it. A species is listed as “threatened” if it is likely to become endangered within the foreseeable future throughout all or most of its range if no action is taken to protect it. The 1973 ESA outlines detailed procedures used by the Services to list a species , including listing criteria, public comment periods, hearings, notifications, time limits for final action, and other related issues.

A species is considered to be federally threaten ed or endangered if one or more of the following listing criteria apply:

 The species’ habitat or range is currently undergoing or is jeopar dized by destruction, modification, or curtailment.

 The species is overused for commercial, recrea tional, scientific, or educational purposes.

 The species’ existence is vulnerable because of predation or disease.

 Current regulatory mechanisms do not provide adequate protection.

 The continued existence of a species is aff ected by other natural or manmade factors.

Information on federally listed T&E species is available from the USFWS Threatened and Endangered Species System (TESS) da tabase (USFWS 2011a), available at: http://ecos.fws.gov/tess_public / and from NMFS at http://www.nmfs.noaa.gov/pr/species/esa/ (NMFS 2011a). Additional information on state-listed species is available from state T&E species coordinators.

The ESA also requires the federal government to de signate “critical habitat” for any species it lists under the ESA. Critical habitat is defined as:

 Specific areas within the geographical area occu pied by the species at the time of listing, if they contain physical or biologi cal features essential to cons ervation, and those features may require special management cons iderations or protection; andConstruction and Development NPDES Ge neral Permit Environmental Assessment

34  Specific areas outside the geographical area occupied by the species if the agency determines that the area itself is essential fo r conservation of a threatened or endangered species and that may require special mana gement and protection. Critical habitat may include an area that is not currently occupied by the species but that will be needed for its
recovery.

Critical habitat designations must be based on the best scientific in formation available, in an open public process, within specific timeframes. The fina l boundaries of the critical habitat area are also published in the Federal Register.

Under Section 7 of the ESA, all Fe deral agencies must ensure that any actions they authorize, fund, or carry out are not likely to je opardize the continued existence of a listed species, or destroy or adversely modify its designated cr itical habitat. Critical habitat has been designated for 607 species listed as threatened or endangere d under USFWS and 24 species liste d as threatened or endangered under NMFS (NMFS 2011a; USFWS 2011a).

3.4 SOCIOECONOMIC RESOURCES The C&D industry plays an integr al role in the nation’s econom y, contributing approximately 5% of the Gross Domestic Product. Approximately 10% of the nation’s nearly 7 million total business establishments are in the C&D industry. The nu mber of paid employees in the C&D industry accounts for 6.6% of total US employment (US Census Bureau 2005a). Establishments in this industry are involved in a wide variety of activities, including land development and subdivision, homebuilding, remodeling, construction of nonresidenti al buildings and other structures, and heavy construction work (including roadways and bridges) . Establishments are also involved in myriad special trades, such as plumbing, roofing, electri cal, excavation, and demo lition work. Some of these activities result in land disturbance, whic h can cause erosion and transport of soil and sediment in stormwater discharges. In devel oping the C&D Rule, EPA conducted a comprehensive study of the socioeconomic impacts of the Rule. Since the CGP must incorporate the requirements of the C&D Rule, some of the an alysis of the socioeconomic imp acts have been incorporated by reference into the EA. (USEPA, 2009b)

3.4.1 L AND U SE According to the Department of Agriculture’s Economic Research Service, the largest proportion (51%) of land use in the US continues to be agri culture; the next largest category of land use, at 22%, is forests. In 2002, urban land comprised only 3% of total US land use. However, urban area increased by 13% between 1990 and 2002. In addition, the estimated acreage of rural land used for residential purposes increased by 30% (17 million acres) from 1980 to 1997 and by 29% (21 million acres) from 1997 to 2002 (USDA, 2006) For the C&D Rule economic impact analysis, EPA c onsidered two categories of land use affects: (1) impacts to existing land uses due to change s in water quality from construction activity discharges; and (2) direct land disturbing acreag e due to development as a measure of C&D activity.Construction and Development NPDES Ge neral Permit Environmental Assessment

35 EPA estimates that as C&D activities continue in areas close to or ad joining agricultural land, impacts from C&D activities may impact agricultu ral areas, particularly water sediment levels. Agriculture depends on water for i rrigation, which may require treatmen t to lower particulate levels to the degree needed to avoid pump and delivery sy stem problems, particularly for drip and fine spray systems. The C&D industry inherently changes land use by either demolishing existing structures and constructing different ones, such as roads and highways, or changing rural or agricultural land into developed land. The C&D industry, as defined by EPA for this pe rmit analysis, comprises three main industry groups:

 Building construction, including

▫ Residential: single-family, multifamily, remodelers, and operative construction

▫ Non-Residential: industrial and commer cial/institutional building construction

 Heavy and civil engineering construction

 Specialty trade contractors: wrecking and demolition contractors, and all other heavy construction. Of these three industry groups, EPA considers only the first two as likely to engage in landdisturbing activities requiring cove rage under the proposed CGP. The activities EPA considers to be land-disturbing activities include si te clearing or preparation activ ities, such as tree removal, excavation, blasting, scraping, grading, etc. Thes e activities can destab ilize soils and create conditions that allow stormwater to accumulate and flow across the site. This increase in stormwater flow can cause erosion and lead to the transport of soil particles (USEPA, 2009c). Within the building construction ca tegory, EPA considers residential remodelers as a category that would not be likely to engage in land-disturbing activities. EPA’s C&D Rule economic analysis estimated cons truction activity in term s of acreage developed and how that activity was distributed geographica lly and across C&D industry segments. EPA used development rates and types in different areas of the US from previous years to describe past trends and future activity. EPA utilized US Census da ta and economic activity data to determine the geographic levels of construc tion and development activity. EPA characterized potentially affected acreage into various future land uses, construction project sizes, and project durations as the basis for deve loping mathematical models to represent broad sectors of the C&D industry. Beginning with th e 2003 CGP, the C&D industry submitted Notices of Intent (NOIs) to cover their stormwater discharges under the NPDES general permit. NOI records were characterized on the basis of land use, site construction acreage , and project duration information. EPA identified 36 C&D project groupings based on 12 site size categories, three major land-use types, and 12 categories of project duration . EPA then de veloped a distri bution of model projects in these various categor ies that represented construction projects developed annually and that covered the major C&D industry project type s. To develop the base line profile of acreage activity by state and construction activity sector, EPA distribute d the approximately 853,000 acres affected by C&D activity as projected in the mode l project matrix in proportion to the total 2008- trend value of construction estimat ed to occur in each category.

3.4.2 P OPULATION AND H OUSING In 2009, EPA used The National Land Cover Database (N LCD) as a national source of data on land cover change. NLCD data are publicly availabl e for the years 1992 and 2001(see:Construction and Development NPDES Ge neral Permit Environmental Assessment

36 http://edc2.usgs.gov/pub slists/factsheets/fs 10800.pdf for 1992 and http://www.mrlc.gov/ pdf/ nlcd_ fact_sheet_2001.pdf for 2001). The USGS prepared and released a comparative land use analysis, the NLCD 1992/2001 Retrofit Land Cover Change Product (see http://www.epa.gov/mrlc ; http://www.mrlc.gov/ ). USGS developed this product to offer more accurate direct change analysis between the 2001 and 1992 individual maps. EPA us ed this product to estimate the amount and geographic areas of land converted to urba n land uses in the US between 1992 and 2001. Appendix A graphically presents the NLCD developmen t change for each of the 10 EPA regions. The geographic data from the NLCD overlay maps shows that the most intensive development, represented by the greatest percentage urban change, tends to occu r in and around existing metropolitan areas. However, regional-scale population shifts also have occurred, for example greater population growth in the Southeast versus less growth in the Northeast, and such population shifts also coincide with incr eases in housing development. Howe ver, the time period of the NLCD mapping precedes the real estate downturn of 2008 – 2010 and the significant drop in housing development, particularly for California and Florida. The trends shown in the NLCD maps were also corroborated by su mmary 2010 Census Data. According to the Census data, regi onal population growth tr ends seem to continue with the largest increases in population in the Southern and West ern United States. However, growth rates from 2000 to 2010 were not nearly as dramatic as in th e 2000 census. Other factors related to stormwater discharge impacts also affect housing demand, such as the aesthetic quality of water bodies and the land adjacent to water bodies receiving runoff fr om C&D activity that may increase sediment loadings. Aesthetic degradation of land and water re sources resulting from sediment and other pollutant discharges (e.g., increa sed water turbidity) have resulte d in reduced market value of property. For example, a hedonic price study by Bejr anonda et al. (1999) found that “the rate of sediment inflow entering the lakes has a negative influence on lakeside property rent” (p. 216) (USEPA, 2009b). Discharges from C&D activities can also negativ ely affect the quality and cost of providing drinking water. Sediment and othe r discharged pollutants adversel y affect water quality, and require increased treatment expenditures such as settleme nt ponds, filtration, and chemical treatment. There also is the additional disposal cost of removing sludge that is created dur ing the treatment process (USEPA 2007b).

3.4.3 T RANSPORTATION
Increased sedimentation can lead to increased na vigational difficulties and inefficiencies such as groundings and delays (Osterkamp et al. 1998). Shipping companies may switch to lighter loads or smaller vessels, which are generally less efficient. Removing sediment to keep navigable waterways passable requires dredging, which can be costl y. The U.S. Army Corps of Engineers (USACE) spent more than $9 billion (2008$) from 1995 thr ough 2008 to remove more the 2,600 million cubic yards of sediment to keep waterways passabl e (USACE 2009). EPA c onsidered the possible impacts that increased waterway sedimentati on resulting from C&D activities could have on navigable waterways. One of the most important considerations of sedime ntation is the required dredging and removal of sediment to keep navi gable waterways passable. The USACE spent more than $9 billion over 14 years and removed over 2,615 million cubic yards of sediment/material to dredge waterways and keep them passable (USACE 2009).

3.4.5 C ULTURAL R ESOURCESConstruction and Development NPDES Ge neral Permit Environmental Assessment

37 EPA is subject to Section 106 of the National Historic Preservation Ac t of 1966 and 1996 (NHPA; 16 U.S.C 470). Under Section 106 of the National Historic Preservation Act and its implementing regulations at 36 CFR Part 800 a nd EO 11593, Federal agencies must take into account effects of their undertakings on historic prop erties listed on or eligible for listing on the National Register of Historic Places. Currently, more than 80,000 propert ies have been listed in the National Register. Together these records hold information on more than 1.4 million individual resources--buildings, sites, districts, structures, and objects. Additionally, the proposed act ion covers many of the tribal lands within the United States. Tribal lands in particular have unique cultural resources that are vulnerable to development and construction activities. EPA recognizes that loca l governments and tribal councils are the best source of identifying cultural resources within their communities.

3.4.6 R ECREATION
The Nation’s surface water resources — rivers, streams, lakes, ponds, reservoirs, estuaries, bays, and nearshore waters — are vitally important to the Nation’s recreati onal activities. These uses rely on, and are in part due to, the environmental heal th of our surface water resources. Polluted or sediment-laden water, however, greatly reduces the aesthetic app eal of a variety of recreational activities such as boating; skii ng, boarding and tubing; swimming; diving; fishing; trapping; hunting; and outings to hike, jog, picnic, camp, and view natural re sources and wildlife. Turbidity and suspended sediments are highly visible pollu tants. Murky waters a nd odors are highly visible and notable detractions from the enjoyment gain ed through outdoor activit ies. Sedimentation in surface water bodies reduces their depth and thus their capacity for boating and swimming (Osterkamp et al. 1998). Sediment ation and turbidity also can crea te dangers to boaters and water skiers, boarders, and tubers by concealing submerged hazards.

Sediment-related nutrient loadi ng can lead to algal blooms and oxygen-stressed waters that do not support higher value recreational and commercial fisheries. Sedime nt and other discharges from C&D sites also can greatly reduce fish populations by inhibiting reproduction and survival of an aquatic species (USEPA 2009b). Fish populations are important for subsistence anglers, commercial anglers and fish sellers, and consumers of fish and fish products. Recreational fishing is an important part of the US economy, generating more than $125 billion in economic output and more than one million American jobs. The economic contributions of recreational fishing have grown steadily over the la st several decades ( http://www.asafishing. org/statistics/saleco_trends/index.html ). According to the American S portfishing Association, there were nearly 40 million anglers in the United States in 2006.

Table 3-3. Economic Contribut ions by Type of Fishing

All Fishing Freshwater Saltwater Great Lakes

Anglers, million 29.95 1. 23.04 8.53 1.51

Expenditures/ Retail Sales ($million) 45,335 31,182 11,051 2,524

Total Multiplier Effect (Econ Output), ($million) 124,959 87,954 30,327 7,089Construction and Development NPDES Ge neral Permit Environmental Assessment

38 Salaries, Wages, and Business Earnings ($ million) 38,359 26,468 9,407 2,189

Jobs 1,035,639 709,508 263,898 58,291

Federal, Sates, and Local Taxes ($million) 116,359 11,495 4,017 910 Source: American Sportfishing Association, 2008. Sportfishing in America, An Economic Engine and Conservation Powerhouse. January 2008. Online at: www.asafishing.org

1. Although there are 29.9 million angler s over the age of 16, the USFWS report s there are an additional 8.4 million youths aged 6-15 who fish, so the cited total number of anglers is nearly 40 million

.Construction and Development NPDES Ge neral Permit Environmental Assessment

39 4. ENVIRONMENTAL CONSEQUENCES

4.1 INTRODUCTION In discussing the environmental consequences of the proposed CGP, EPA is drawing a clear distinction between the CGP and the C&D Ru le. NPDES regulations require the CGP to incorporate the requirements of the C&D Rule as a national, technology-ba sed effluent limitation guideline for the construction and development point source industry. During the development and finalization of the C&D Rule, EPA assessed and evaluated the costs a nd benefits that derive from the C&D Rule. In the CGP, EPA is implementing the requirements of the C&D Rule. Thus, when considering the costs and benefits of issuing the proposed CGP, EPA attributes these costs and benefits to the technology-base d requirements of the C&D Rule, and not to the issuance of the general permit, which is the Federal action triggering this NEPA review. In presenting the potential environmental impacts from the CG P, EPA points out the distinction between those that derive from, and are an inhe rent part of, the C&D Rule and those that are attributable to the CGP itself. An analysis of the requirements of the pr oposed CGP concluded that other than requirements included in the C&D Rule or the existing CGP, and other existing EPA regulations, the CGP has only one additional, new requirement: an increase in inspection frequency for some permittees and more detailed requireme nts regarding inspections during storm events causing discharge. From this new requirement, there is neither material cost nor immediate, direct environmental benefit. Thus in the remainder of this chapter, although environmental costs and benefits related to issuing the pr oposed CGP are discussed, these cost s and benefits derive primarily from the incorporation and implementation of the C&D Rule, and are not directly attributable to the CGP itself.

4.2 BASIS FOR COMPARISON OF AL TERNATIVES AND APPROACH TO ALTERNATIVES ANALYSIS The proposed CGP contains a number of changes in administrative, procedural, and reporting requirements. However, these changes are primar ily intended to streamline and or clarify the requirements of the proposed CGP and are negligible factors in assessing the costs or environmental consequences of the proposed CGP. The new te chnical requirements of the proposed CGP derive overwhelmingly from the implementation of the C&D Rule. The costs and benefits of the C&D Rule were subject to extensive public review and comment from st akeholders and Federal and state agencies, and were considered and addressed in the promulgation of the final C&D Rule. However, implementation of the C&D Rule thr ough the proposed CGP none theless represents a material change as compared to the requirements of the current CGP. These changes are substantial enough that ignoring the environmental impacts, costs, and benefits of the C&D Rule is inappropriate in the context of pe rforming a NEPA review of this Federal action. In preparing this EA for the proposed CGP, EPA has relied on the da ta collection, review, a nd analyses performed by the Agency in developing the C&D Rule. EPA considers its reliance on the C&D rulemaking record a valid approach to performing a NEPA review of the environmental impacts of the proposed CGP in this EA.

4.2.1 B ACKGROUND ON THE C&D R ULE
The C&D Rule considered four re gulatory options in the development of the final Rule. For the baseline (i.e., then current conditions) and each regulatory option, EPA performed a series of analyses. EPA estimated technology-based reductions in sediment discharges from constructionsConstruction and Development NPDES Ge neral Permit Environmental Assessment

40 sites, relative to baseline, as described in Development Document for the final Rule (USEPA 2009a). EPA estimated changes in in-stream sedime nt and nutrient concentr ations accruing from these reductions in sediment loadings, relative to baseline, to estimate environmental benefits as described in the Benefits Assessment for the fi nal rule (USEPA 2009b). EPA also estimated the compliance costs to the industry to achieve thes e reductions in sediment loadings, relative to baseline, as described in Economic Asse ssment for the final rule (USEPA 2009c). EPA selected the technologies described under Op tion 1 as the BPT level of control for toxic pollutants and BCT level of control for conventiona l pollutants. EPA made this selection because the specified nonnumeric requirements of Option 1 represent a level of control that is technologically available and economically practi cable and represents the average of the best performance of construction sites in the C&D industry. For national, technology-based pollution control, EPA selected Option 4 as the basis for both BAT and N SPS because the requirements of Option 4 were demonstrated to be technologica lly available, economically achievable, pose no barrier to entry, and have acceptable non-water quality environmental impacts. Subsequent to promulgation of the final C&D Rule, several petitioners submitted comments on the appropriateness of the data analysis that EPA used to derive the numeric turbidity limits. Upon review of the submitted comments, EPA agreed that the data and analysis performed in the development of the final numeric limit did not support the final li mit. EPA has stayed implementation of the numeric turbidity limit portion of the rule pending its re-analysis. Option 4 has identical requirements for BAT and NSPS. Thus, the practical effect of the final C&D Rule is that NSPS is the industr y standard of performance for stor mwater runoff from C&D sites. One reason is that all sites, wh ether existing or new sources, are required to meet BAT limitations. A second reason is that is the majority of C&D in dustry projects are of a relatively short-term nature, with a median project duration of 9.4 months 6

. Over the anticipated life of the proposed CGP (5 years from issuance), EPA NOI application data indicate that existing sources will decrease from a range of 4% - 8% in 2013 to approximately 1% by 2017 ( see Table 2-1 ). Thus, EPA has determined that for the purposes of this NEPA review all C&D industry activity is from new sources and, th erefore, the EA only di scusses the results of EPA’s analyses for Option 4 of the C&D Rule as re levant to potential envi ronmental consequences.

4.2.2 A PPROACH TO THE C OMPARISON OF A LTERNATIVES The C&D Rule developed national, industry-wide estimates of pollutant reductions, compliance costs, and benefits to assess th e impacts of a national effluent limitations guideline rulemaking. In contrast, the proposed CGP only covers a small portion of C&D industry activity, defined by the scope of coverage of the proposed CGP. Thus, the EA presents an analysis of impacts based on the estimated C&D activity projected to be covered under the proposed CGP, i.e., only affecting C&D activities in four states, the District of Columbia , US territories, Indian lands, and some Federal lands. The qualitative impacts of the CGP a nd C&D Rule are identical; they only differ quantitatively. To review the potential environm ental consequence of the propos ed CGP, EPA has disaggregated the C&D activity for the proposed CGP from the na tional-level assessments developed for the C&D Rule. To determine the portion of C&D activity covered under the proposed CGP, EPA compared

6 Based on an analysis of data fr om 46,740 available NOI applications.Construction and Development NPDES Ge neral Permit Environmental Assessment

41 the C&D activity under the existing CGP, based on data from CGP NOI applications submitted to EPA to the national estimate of C&D activity de veloped in the economic assessment for the C&D Rule ( Table 4-1 ). The annual number of NOI applications was obtained from EPA’s eNOI database covering the period 2004 through 2011. Because th e C&D Rule economic assessment analyses were normalized to 2008 dollars, EPA used the NOI data for 2008 for comparison to the C&D Rule
assessments. The economic assessment for the C&D Rule proj ected a national C&D industry activity of 128,536 projects; and the C&D activity c overed under the existing CGP coveri ng essentially the same year totaled 5,960 projects, or 4.6% of the national C&D activity. There is about a two-fold difference in annual activity between 2004 and 2011, ranging from 3,730 to 7,316 projects. However, the 8-year average activity is 5,846 projects, nearly identical to the projects reported in 2008. To maintain the consistency for this analysis, EPA is using the fi gures from 2008, and an estimated percentage of CGP C&D activity of 4.5% of tota l national C&D activity, applied to the projected benefits and costs presented in the C&D Rule national assessment to estimate CGP impacts.

4.3 IMPLEMENTATION OF BEST M ANAGEMENT PRACTICES (BMP’s) Construction site operators comply with the CG P through the implementation of variety of Best Management Practices (BMPs) which minimize the discharge of pollutants from construction site stormwater discharges when selected, implemen ted, and managed as inte nded. Construction site operators have the discretion of c hoosing the BMPs that meet the re quirements of the permit and of their project. While the CGP does no t dictate that any specific BMP be installed on a site; operators must meet both non-numeric and wate r quality-based effluent limitati ons to gain coverage under the CGP which includes meeting restrictions on eros ion and sediment controls, pollution prevention, and site stabilization as required by the C & D ru le. Therefore, through implementation of BMP’s Table 4-1. eNOI Statistics on C&D Indus try Applications Under the Existing CGP
Year No. NOI Applications

2004 5,293

2005 7,316 2006 6,392

2007 6,091

2008 5,960 (4.6%) 2009 5,091

2010 4,778

2011 1 3,730 Average, 2004-2010 5,846 (4.5%)
National Total C&D Activity 2 2008 128,536

1. The projected number is based on NOI applications through June 30, 2011, prorated to 49% (the average percentage of applications submitted from January 1 through June 30, 2004-2010).
Source: EPA 2009cConstruction and Development NPDES Ge neral Permit Environmental Assessment

42 by operators, the adverse environmental and so cio-economic impacts to resources discussed throughout this chapter are minimized.

There are five categories of stormwater BMPs for construction activities. These are listed at : http://cfpub.epa.gov/npdes/stormwater/menuo fbmps/index.cfm?action=min_measure&min_ measure_id=4

. These include: construction site planning and management, erosion control, runoff control, sediment control and good housekeeping/ materials management. The information EPA presents for each stormwater BMP generally includes, with some exceptions: a description, applicability, siting/design considerations, limitati ons, maintenance considerations effectiveness, and cost considerations. This information also includes potential advers e environmental effects related to the BMP. This information on listed co nstruction site stormwater BMPs is summarized below.

4.3.1 Construction Site Planning and Management Construction sequencing is a specified work schedule thatcoordinates the timing of landdisturbing activities and the instal lation of erosion and sediment c ontrol measures to reduce on-site erosion and off-site sedimentation by performing land-disturbing activities and installing control practices according to a planned schedule (Smole n et al. 1988). Construc tion site phasing involves disturbing only part of a site at a given time to prevent erosion from dormant areas; site phasing needs to be considered early in overall site pla nning. Construction sequencing can be used to plan earthwork and erosion/sediment c ontrol activities where land dist urbance may affect water quality in a receiving waterbody. The erosion and sedi ment control plan should state the proposed schedule and a protocol to make changes for unforeseen problems.

Construction sequencing can be an effective tool for erosion and sediment control because it ensures that management practices are installed where necessary a nd when appropriate. Flexibility allows for updating the plan to maximize the effec tiveness of erosions and sediment control BMPs under changing conditions. A comparison of sediment loss from a typical development and from a comparable phased project showed a 42 percent reduc tion in sediment export in the phased project (Claytor 1997).

Construction Site Operator BMP Inspections and Maintenance are essential to managing construction site stormwater r unoff. Three types of BMP inspections are performed: routine inspections and inspections performe d before and after rain events. Routine inspections are integral parts of regular maintenance activities to ensure the integrity and effectiveness of BMPs and to observe whether site conditions have changed and rendered in itial BMP designs inadequate. Awareness and education of genera l soil and sediment controls through this BMP expedites the repair and maintenance efforts by raising issues early.

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 he lps to control surface runoff, soil erosion, and sedimentation during and after cons truction. Land grading is applicab le to sites with uneven or steep topography or easily erodible soils, because it stabilizes slope s and decreases runoff velocity. Grading activities should maximally maintain ex isting drainage patterns . Land grading is a key consideration for Construction Sequencing. Impr oper grading practices can disrupt naturalConstruction and Development NPDES Ge neral Permit Environmental Assessment

43 stormwater patterns and lead to poor drainage, high-runoff velocities, and increased peak flows during storm events. Clearing and gr ading the entire site without ve getated buffers promotes offsite transport of sediments and other pollutants. Howe ver, land grading is an effective way to reduce steep slopes and stabilize highl y erodible soils when properly implemented with stormwater management and erosion and sediment control practices.

Preserving Natural Vegetation protects desirable trees, vines, bushes, and grasses from damage during site development. Vegetation provides eros ion control, stormwater detention, biofiltration, and adds aesthetic values during and after construction activities. Preserving natural vegetation is applicable where predevelopment vegetation exists. The practice can be especially beneficial for floodplains, wetlands, stream banks, steep slopes, and other areas wh ere erosion controls would be difficult to establish, install, or maintain. Natura l vegetation (existing tree s, vines, brushes, and grasses) can provide water quality benefits by inte rcepting rainfall, filtering stormwater runoff, and preventing sediments and other pollu tants from leaving the site.

4.3.2 Erosion Control
Chemical Stabilizers (soil binders or soil palliatives) provid e temporary soil stabilization to reduce soil erosion from runoff and wind where vegetation cannot be established, and provide immediate protection. Chemical stabilizers ar e used alone, where other stabi lization methods are ineffective due to environmental constraints, or used along w ith vegetative or perimeter practices to enhance erosion/sediment control. Chem ical stabilization is usually more expensive than vegetative practices. In general, the effec tiveness of polymer stab ilization methods range s from 70 percent to 90 percent. The effectiveness of a polymer de pends on soil type, application method, and the polymer's individual chemical characteristics (Aicardo 1996).

Compost Blankets are a layer of loosely applied compost or composted material, placed on soil in disturbed areas to control erosi on and retain sediment due to sheet-flow runoff. These blankets prevent stormwater erosion by presenting a more permeable surface to oncoming sheet flow and facilitating infiltration; by filling in small r ills and voids to limit channelized flow; and by promoting establishment of surface vegetation. Com post blankets can be placed on any soil surface: rocky, frozen, flat, or steep and are made from a variety of feedstocks, including municipal yard trimmings, food residuals, separated municipal solid waste, biosolids, and manure. Advantages provided by compost blankets include the following (Alexander 2003; Faucette 2004):

• The compost retains a large volume of water, wh ich helps reduce runoff, prevents or reduces sheet and rill erosion, and aids in establishing vege tation in the blanket.

• The compost blanket acts as a buffer to ab sorb rainfall energy, which prevents soil compaction and crusting and fac ilitates rainfall infiltration.

• Compost blankets facilitate plant growth by cap turing and retaining moisture and providing a suitable microclimate and nutrients for seed germination.

• The compost stimulates microbial activity, which increases decomposition of organic matter, increases nutrient availability for plants, and improves the soil structure.

• Compost can remove pollutants, such as hea vy metals; nitrogen; phosphorus; oil and grease; and fuel, from stormwater, thus improving downstream water quality (W&H Pacific 1993; USEPA 1998).Construction and Development NPDES Ge neral Permit Environmental Assessment

44 Numerous studies conducted by a variety of uni versities and State DOTs have reported the effectiveness of compost blankets. A University of Georgia research trial (Faucette and Risse 2002) reported that correctly applied compost blankets provide almost 100 percen t soil surface coverage, while other methods (e.g., straw mats and mulche s) provide only 70 to 75 percent coverage. Uniform soil cover by the compost blanket is a ke y component to effective erosion and sediment control because it helps maintain sheet flow and prevents stormwater from forming rills under the blanket. Compost blankets also he lp protect the structural stability of the slope, particularly when vegetated.

An Iowa State University study (Glanville et al. 2003), sponsored by the Iowa Department of Natural Resources and Iowa DOT, compared compos t-treated road embankments to conventionally treated embankments (i.e., topsoil ad ded to surface). The results showed that the 2- and 4-inch thick compost blankets reduced runoff from the embank ment by 80 percent. The erosion rate from the compost blanket was less than 1 percent of that from the non-composted areas, and weed growth on compost-treated areas was approximately 25 percent of that on untreated areas.

Dust Control BMPs reduce surface activities and air move ment that generate dust from disturbed soil surfaces. Dust control measures at a site de pend on site topography and land cover, site soil characteristics, and rainfall. Earthmoving activit ies are the major source of dust from construction sites, but traffic and general disturbances can also be major contributo rs (WA Dept. of Ecology 1992). Construction sequencing and disturbing only small areas at a time can greatly reduce dust from a site. Control measures a nd design criteria include : sprinkling/irrigation; vegetative cover; mulching; wind breaks; deep tillage; stone; and spray-on chemical soil treatments.

The effectiveness of various dust control BMP’s include:

• Mulch . Can reduce wind erosion by up to 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 permeability of the barrier will change its effectiveness at capturing windborne sediment.

• Tillage . Roughening the soil can reduce soil loss es by approximately 80 percent in some situations.

• Stone . The size of the stones can affect the amount of erosion to take place. In areas of high wind, small stones are not as effective as 20 cm stones.

• Spray-on Chemical Soil Treatments (palliatives) . Effectiveness of pol ymer stabilization methods range from 70 percent to 90 percent.

Geotextiles are porous fabrics also known as filter fabric s, road rugs, synthetic fabrics, construction fabrics, or simply fabrics. Geotextiles are used for many purposes, e.g., separators, reinforcement, filtration and drainage, and erosion control (U SEPA 1992). Geotextiles can aid plant growth by holding seeds, fertilizers, and tops oil in place. Fabrics are made to match specific site needs and are relatively inexpensive for some applications. Geotex tiles can be used in va rious ways for erosion control on construction sites. Use them as matting to stabilize the flow of channels or swales or to protect seedlings on recently planted slopes until th ey become established. Use matting on tidal or stream banks, where moving water is likely to wash out new plantings. Geotex tiles can be used to protect exposed soils immediately and temporarily, such as when active piles of soil are leftConstruction and Development NPDES Ge neral Permit Environmental Assessment

45 overnight. They can also be used as a separator between riprap and soil, which prevents the soil from being eroded from beneath the ripr ap and maintains the riprap's base.

Gradient Terraces are earthen embankments or ridge and channel systems that reduce erosion by slowing, collecting and redistributing surface runoff to stable outlets that increase the distance of overland runoff flow. Terraces hold moisture and help trap sedime nts, minimizing sediment-laden runoff. Gradient terraces are most effective in barren areas with an existing or expected water erosion problem. They are effective only if su itable runoff outlets are available, e.g., grassed waterways, vegetated areas, or tile outlets.

Mulching is an erosion control practi ce using materials such as grass, hay, wood chips, wood fibers, straw, or gravel to stabilize exposed or recently planted soil surfaces. Mulching is highly recommended and most effective used along w ith vegetation, although it is often used where vegetation cannot be established. In addition to soil stabilizati on, mulching can reduce stormwater velocity and improve the infiltration. Mulching ca n aid plant growth by holding seeds, fertilizers, and topsoil in place; preventing birds from eating seeds; retaining moisture; and insulating plant roots. Mulching effectiveness varies according to the type of mulch used. Soil loss reduction for different mulches ranges from 53 to 99.8 percent. Water velocity reductions range from 24 to 78 percent (Harding 1990).

Riprap is a layer of large stones used to protect soil from erosion in areas of concentrated runoff. Riprap can also be used on slopes that are unstabl e because of seepage problems. Riprap stabilizes cut-and-fill slopes; channel side slopes and bottoms ; inlets and outlets for culverts, bridges, slope drains, grade stabilization structur es, and storm drains; and stream banks and grades. Steep slopes limit the applicability of riprap: slopes greater th an 2:1 can cause riprap loss from erosion and sliding and if used improp erly, can increase erosion.

Seeding is used to control runoff and erosion on disturbed areas by establishing perennial vegetative cover. It reduces er osion and sediment loss and pr ovides permanent stabilization. Seeding is economical and adaptable to different site conditions, allo wing selection of a variety of plant materials. Perennial vegetative cover fr om seeding has been shown to remove between 50 and 100 percent of total suspended solids from stor mwater runoff, with an average removal of 90 percent (USEPA 1993). The effectiveness of seeding can be limited by high erosion during establishment, the need to reseed areas that fail to establish, limited seeding times, or unstable soil temperature and soil moisture content during ge rmination and early growth. Seeding does not immediately stabilize soils, thus requiring temporary erosion and sediment control measures to prevent pollutants from disturbed areas from being transported off the site.

Sodding is a permanent erosion control practice and i nvolves laying a continuous cover of grass sod on exposed soils. Sodding stabilizes disturbed ar eas and reduces stormwater runoff velocity. Sodding is useful for any graded or cleared area that may erode or requir es immediate vegetative cover or stabilize channels or swal es that convey concentrated flow s and reduce flow velocities. Sod removes up to 99 percent of total suspende d solids in runoff, but its sediment trapping efficiency is highly variable depending on hydrologic, hydraulic, vegetation, and sediment characteristics.Construction and Development NPDES Ge neral Permit Environmental Assessment

46 Soil Retention measures are structures or practices that hold soil in place or keep it contained within a site boundary. They incl ude grading or reshaping the ground to lessen steep slopes or shoring excavated areas with wood, concrete, or steel structures. So me soil-retaining measures are used only for erosion control; ot hers are also used to protect workers during excavations. When sites have very steep slopes or loose, highly erodible soils that render other methods ineffective, reinforced soil-retaining structures are used. Soil-retention structures, if properly designed and installed, can effectively prevent erosion in areas with steep slope s and erodible soils. The potential for failure depends on the design, installation, and ma intenance of the struct ures, and the likelihood of catastrophic events such as heavy rains, earthquakes, and landslides.

Soil Roughening is a temporary erosion control practice often used with grading. Soil roughening increases the relief of bare soil surfaces with horizontal grooves by stair-stepping (parallel to soil contours) or tracking with constr uction equipment. Slopes left in a roughened condition or not fine graded can also reduce erosion. It reduces runoff velocity, increas es infiltration, reduces erosion, traps sediment, and prepares the soil for seeding and planting by giving seed an opportunity to take hold and grow.

Temporary Slope Drains are flexible, temporary conduits for st ormwater that extend the length of a disturbed slope to eliminate gully erosion from c oncentrated flows and dive rt flow. Constructing and removing more permanent drains usually dist urb the surrounding area; erosion and downstream soil movement often occur. Temporary slope drai ns, also called pipe sl ope drains, convey runoff without causing erosion on or at the bottom of the slope. They are used during grading until permanent drainage structures are installed a nd slopes permanently stabilized. Temporary slope drains can be used on mo st disturbed slopes.

Temporary stream crossings provide for safe, stable constr uction vehicle traffic crossing of watercourses. Temporary stream crossings provid e stream bank stabilizat ion, reduce the risk of damage to the streambed or channel, and minimi ze sediment loading from construction traffic. Culverts obstruct stream flows, interfere with migrating fis h, and are vulnerable to washout. Excavating the streambed and approach to lay riprap or other stabilization material causes major stream disturbance, with mud and other debris tr ansported directly into the stream unless conducted only during periods of low flow.

Sand Fences are barriers made of small, evenly spaced wooden slats or fabric, erected to reduce wind velocity and to trap blowing sand. Sand fen ces can be used as perimeter controls around open construction sites to keep sediments from being blown offsite. They prevent offsite damage to roads, streams, and adjacent properties. Wind fen ces are appropriate on ar eas with loose, finetextured soils that can be tran sported offsite by winds. The spaces between the fence slats allow wind and sediment to pass through but reduce the wind's speed, causing sediment to deposit along the fence.
4.3.3 Runoff Control Check Dams are relatively small, temporary structures constructed across a swal e or channel. They slow the velocity of concentrat ed water flows, reducing erosi on. As stormwater runoff flows through the channel, check dams catch sediment from the channel itself or the contributing drainage area. They are typically construc ted out of gravel, rock, sandbags, logs or treated lumber, or strawConstruction and Development NPDES Ge neral Permit Environmental Assessment

47 bales and are most effective wh en used with other stormwater , erosion, and sediment-control measures. Field experience has shown that rock check dams are more effective than silt fences or straw bales to stabilize wet-weather ditches ( VDCR 1995). For long channels, check dams are most effective when used in a series, creating mu ltiple barriers to sediment-laden runoff.

Grass-lined Channels convey stormwater runoff through a stab le conduit and slow concentrated runoff through vegetation lining the channel. Grassed channels are not usually designed for peak runoff control by themselves but are often used with other BMPs (e.g., subsurface drains; riprap stabilization). On moderately steep slopes n eeding drainage, grassed channels can include excavated depressions or check dams for enhanc ed runoff storage, decreased flow rates, and improved pollutant removal, or by temporarily reta ining runoff in the channel. Pollutants can be removed from stormwater by filtration through ve getation, by deposition, or in some cases by infiltration of soluble nutrients into the soil. Th e degree of pollutant remo val in a channel depends on how long the water stays in the channel and the amount of contac t with vegetation and the soil surface.

Permanent Slope Diversions are designed to transport runoff dow n slopes in a way that minimizes potential erosion. Diversions ar e constructed by creating channe ls laterally across slopes to intercept down-slope runoff flows. Channels have supporting earthen ridges on the bottom sides to reduce slope length, collect stormwater runoff, a nd deflect runoff to outlets that won’t cause erosion. Diversions can also pr omote vegetation growth by redi recting flows while vegetation becomes established. Diversions should be wher e uncontrolled runoff may cause property damage from erosion or resulting sedimentation.

Temporary Diversion Dikes are earthen perimeter c ontrols consisting of a ri dge of compacted soil, often accompanied by a ditch or swale with a vegeta ted lining. They occur at the top or base of a sloping disturbed area or along and with in the perimeter of the disturbed part of a site. They are also called earth dikes or interceptor dikes. They all serve to contro l the velocity and/or route of sediment-laden stormwater runoff. Dikes are effective at divert ing sediment-laden stormwater runoff around a disturbed area; however, concentr ated channel runoff has increased erosion potential.

4.3.4 Sediment Control Brush Barriers are perimeter sediment control structures constructed of material from site clearing and grubbing, e.g., small tree branches, root mats, stone, or other debris. Brush barriers can be covered with filter cloth to stab ilize the structure and improve ba rrier efficiency. Brush barriers provide temporary storage for larg e amounts of cleared material from a site, however, this material should be removed after constructio n activities cease and th e site is stabilize d. Brush barriers can be effective at reducing offsite se diment transport, and their effec tiveness is greatly increased with the use of a fabric cover on the up- slope side of the brush barrier.

Compost Filter Berms are dikes of compost or a compost pr oduct, placed perpendicular to sheet flow runoff to control erosion in disturbed areas and retain sediment. They are used in place of traditional sediment and erosion controls, such as a silt fence or straw bale barrier. The compost filter berm is trapezoidal in cross section, and provides a three-dimensional filter that retains sediment and other pollutants while allowing clea ned water to flow through. A compost filter bermConstruction and Development NPDES Ge neral Permit Environmental Assessment

48 can be used as a check dam in small drainage ditches. Using compost in the berm provides additional benefits, including the rete ntion of large volumes of water, sediments, and pollutants that improve water quality downstream and reduce erosion. Nutrients and hydrocarbons trapped by compost filters can be naturally cycled and d ecomposed through bioremediation by microorganisms commonly found in the compost matrix (USEPA 1998). A study conducted in Portland, Oregon (W&H Pacific 1993) compared the effectiveness of a silt fence and a mixed yard debris compost filter berm to a control plot during five storm even ts. The study found that the filter berm was over 90 percent effective in removing se ttleable and total suspended solids when compared to the control plot and was approximately 66 percent more effec tive than the silt fence. Another quantitative study performed by the Snohomish County, Washingt on, Department of Planning and Development Services (Caine 2001) showed no decrease in turb idity with a silt fence but a 67 percent reduction in turbidity using a compost filter berm.

Compost Filter Socks are a contained compost filter berm. They are mesh tubes filled with composted material, placed perpendicular to sheet- flow runoff. The compost filter sock provides a three-dimensional filter that retains sediment a nd other pollutants while al lowing cleaned water to flow through (Tyler and Faucette 2005). Filter sock s are used in place of traditional sediment and erosion controls such as a silt fence because: in stallation does not require disturbing the soil surface which reduces erosion, it is easily removed and the operator must dis pose of only a relatively small volume of material (the mesh). Filter socks, due to their flexibility, are especially useful on steep or rocky slopes where installation of ot her erosion control tools is not f easible. In addition to retaining sediment, compost can retain pollutants and im prove the downstream water quality. Absorbed and/or trapped nutrients or pollutants can be naturally cy cled and decomposed through bioremediation by microorganisms comm only found in the compost matrix.

A large number of qualitative studies have reported the effectiveness of compost filter socks in removing settleable solids and total suspended solids from stormwater (McCoy 2005; Tyler and Faucette 2005). These studies have consistently shown that compost filter socks are at least as effective as traditional erosion and sediment cont rol BMPs and often are more effective. Compost filter socks are often used in conjunction with com post blankets to form a stormwater management system. Together, these two BMPs retain a very high volume of stormwater, sediment, and other pollutants. The compost in the filter sock can also improve water quality by absorbing various organic and inorganic contaminan ts from stormwater, including motor oil. Tyler and Faucette (2005) conducted a laboratory test using 13 types of compost in filter socks. They found that half of the compost filter socks removed 100 percent of the motor oil introduced into the simulated stormwater and the remaining compost filter sock s removed over 85 percent of the motor oil from the stormwater.

Construction Entrance Stabilization serves to minimize the amount of sediment leaving the area as mud/ sediment attached to vehicl es. Installing a pad of gravel ove r filter cloth where construction traffic leaves a site helps stabilize a construc tion entrance and removes mud/sediment from the wheels, reducing soil offsite transport. The filter cloth separates gravel from the soil below so gravel isn’t ground into the soil and reduces ru tting caused by vehicle tires by spreading the vehicle's weight over a soil area larger than the tir e width. Site entrance stabilization should be used at any roadway or where vehicles enter or leave the site and should be in place before construction and further site disturbance begin.Construction and Development NPDES Ge neral Permit Environmental Assessment

49 Fiber Rolls (also called fiber logs or straw wattles) are tube-shaped erosion-control devices filled with straw, flax, rice, coconut fi ber material, or composted materi al. Each roll is wrapped with UVdegradable polypropylene netting fo r longevity or with 100% biodegr adable materials like burlap, jute, or coir. Fiber rolls complement permanent BMPs for source control and re-vegetation. When installed in combination with st raw mulch, erosion control blanke ts, hydraulic mulches, or bounded fiber matrices for slope stabilization, these device s reduce the effects of l ong or steep slopes. Fiber rolls also help to slow, filter, and spread overla nd flows, which helps prev ent erosion and minimizes rill and gully development. Fiber rolls also he lp reduce sediment loads to receiving waters by filtering runoff and capturing sediments.

Unlike other BMPs that could cause water to back up and flow ar ound the edges, fiber rolls allow water to flow through while capturing runoff sedime nts. Fiber rolls placed along the shorelines of lakes and ponds provide immediate protection by dissipating the erosiv e force of small waves. As an alternative to silt fences, fi ber rolls have some distinct ad vantages, including the following (Earth Saver 2005):

• They install more easily, particularly in shallow soils and rocky material.

• They are more adaptable to slope applications and contour installati ons than other erosion and sediment control practices.

• They are readily molded to fit the bank line.

• They blend in with the landscape and are less obtrusive than other erosion and sediment controls such as silt fence.

• They do not obstruct hydraulic mulch and seed applications.

• They can be removed or left in place after vegetation is established.

Fiber rolls can provide slope pr otection for 3 to 5 years (California Straw Works 2005). They slowly decompose into mulch, and the netting br eaks down into small pieces. The San Diego State University Soil Erosion Research Laboratory reported that the use of fiber roll products reduced offsite sediment delivery by 58 percent (International Erosio n Control Association 2005).

Gravel or Stone Filter Berms are temporary ridges made of l oose gravel, stone, or crushed rock. They slow and filter flow and divert it from open tr affic areas and are considered an efficient form of sediment control. One type of filter berm is the continuous berm, a geosynthetic fabric berm that captures sand, rock, and soil. Gravel or stone filte r berms are most suitable in areas where traffic needs to be rerouted because ro ads are under construction, or in tr affic areas within a construction site. Berms are intended to be used only in ge ntly sloping (<10%) areas. The effectiveness has been rated at up to 95 percent for sediment re moval and depends on local conditions such as hydrologic, hydraulic, topographic, and sediment characteristics.

Sediment Basins and Rock Dams can be used to capture sediment from stormwater runoff before it leaves a construction site. Both structures allow a pool to form in an excavated or natural depression, where sediment can se ttle. The pool is dewatered thr ough a single riser and drainage hole leading to a suitable downstream outlet or th rough the gravel of a rock dam, releasing water more slowly than without the control structure. A sediment basin is cons tructed by excavation or erecting an earthen embankment acr oss a low area or drainage swal e. Some sediment basins areConstruction and Development NPDES Ge neral Permit Environmental Assessment

50 designed to drain completely du ring dry periods while others retain a shallow pool of water between storm events. Rock dams are similar to sediment basins with earthen embankments except constructed of rock and gravel . They release water from the settling pool gradually through the spaces between the rocks.

The effectiveness of a sediment basin depends prim arily on the sediment particle size and the ratio of basin surface area to inflow rate (Smolen et al. 1988). Basins with a large surface area-to-volume ratio are the most effective. USEPA (1993) estimates an average total suspended solids removal rate for all sediment basins of 55 percent to 100 per cent with an aver age effectiveness of 70 percent.

Sediment Filter Systems and Chambers can be confined or unconfin ed, on-line or off-line, and aboveground or belowground. Confined sediment filte rs are constructed with the filter medium contained in a structure, often a concrete vault. Unconfined sediment filters are made without a confining structure. On-line systems retain stormwat er in its original stream channel or storm drain system. Off-line systems divert stormwater. Se diment filters are usually limited to removing pollutants from stormwater runoff.

Treatment effectiveness depends on factors like treatment volume; whether the filter is on-line or off-line, confined or unconfined; and the type of land use in the contri buting drainage area. MWCOG (1992) states that sand filter removal rates are "high" for sediment and trace metals and "moderate" for nutrients, biochemical oxygen demand, and fecal coliform bacteria. Removal rates can be increased slightly by using a peat/sand mixt ure as the medium because peat has adsorptive properties (pollutants attach to it) (MWCOG, 1992). The estimated pollutant removal capabilities for various filter systems are shown below:

Pollutant removal efficiencies for sand filters

Source Filter system TSS a (%) TP a (%) TN a (%) Other pollutants

Claytor and Schueler, 1996 Surface sand filter 85 55 35 Bacteria: 40%-80% Metals: 35%- 90%
Perimeter sand filter 80 65 45 Hydrocarbons: 80% Livingston, 1997 Sand filter (general) 60-85 30-75 30-60 Metals: 30%- 80%

a TSS=total suspended solids; TP=tot al phosphorus; TN=total nitrogen.

Sediment Traps are small impoundments that allow sediment to settle out of construction runoff. They are usually installed in a drainage way or other point of discharge from a disturbed area. Temporary diversions can be used to direct r unoff to the sediment trap (USEPA 1993). Sediment traps detain sediments in stormwat er runoff to protect receiving str eams, lakes, drainage systems, and the surrounding area. Sediment traps are commonly used at the outlets of stormwater diversion structures, channels, slope drai ns, construction site entrance wa sh racks, or any other runoff conveyance that discharges waters containing sediment and debris . Although sediment traps allowConstruction and Development NPDES Ge neral Permit Environmental Assessment

51 eroded soils to settle, their detent ion periods are too short for removi ng fine particles like silts and clays.

Sediment trapping efficiency is a function of surface area and peak inflow rate (Smolen et al. 1988). Traps that provide pools with larg e length-to-width ratios have a greater chance of success. Sediment traps have a useful life of about 18 to 24 months (USEPA 1993), but their effectiveness depends on the amount and intensity of rainfa ll and erosion, and proper maintenance. USEPA (1993) estimates an average total suspende d solids removal rate of 60 percent.

Silt Fences are used as temporary perimeter controls around sites where cons truction activities will disturb the soil and apply to construction sites w ith relatively small drainage areas. Silt fences consist of a length of filter fabr ic stretched between an choring posts spaced at regular intervals along the site at low/downslope areas. The filter fabric should be entrenched in the ground between the support posts. When installed co rrectly and inspected frequently, si lt fences can be an effective barrier to sediment leaving the site in stormwater runoff.

USEPA (1993) reports the following effectiveness ranges for silt fences constructed of filter fabric that are properly installed and well maintained : average total suspended solids removal of 70 percent, sand removal of 80 to 90 percent, silt-l oam removal of 50 to 80 pe rcent, and silt-clay-loam removal of 0 to 20 percent. Removal rate s are highly dependent on local conditions and installation.

Storm Drain Inlet Protection measures prevent soil and debris from entering storm drain drop inlets and are usually temporary and implemented be fore a site is disturbed. Inlet protection can be: excavating around the perimeter of the drop inlet; fa bric barriers around inlets ; and block and gravel protection. Sandbags also are used to create temporar y sediment barriers at inlets. Excavated drop inlet protection can be used to improve the effectiv eness and reliability of other sediment traps and barriers, such as fabric or bloc k and gravel inlet protection. The effectiveness of inlet protection alone is low for erosion and sediment control, l ong-term pollutant removal, and habitat and stream protection.

Straw or Hay Bales have historically been used on cons truction sites for erosion and sediment control as check dams, inlet prot ection, outlet protection, and perimeter control. Many applications of straw bales for erosion and sediment control ar e proving ineffective due to the nature of straw bales degrading and rotting, inapprop riate placement, inadequate in stallation, or a combination of all three factors (Fifeld 1999). Since many applications of straw and hay bales have been ineffective, EPA recommends that other BMP options are considered su ch as silt fences, rock check dams, fiber rolls, compost blankets or gravel bags.

Vegetated Buffers are areas of natural or established vege tation maintained to protect water quality of neighboring areas. Buffer zones slow stormwat er runoff, provide an area where runoff can permeate the soil, contribute to ground water rech arge, and filter sediment. Slowing runoff helps prevent soil erosion and stream bank collapse. Se veral studies indicate greater than 90 percent reductions in sediment and nitrate concentrations when vegetated buffers are used. Buffer/filter strips do a reasonably good job of removing phosphorus attached to sediment, but they are not so effective at removing dissolv ed phosphorus (Gilliam 1994).Construction and Development NPDES Ge neral Permit Environmental Assessment

52 4.3.5 Good Housekeeping/Materials Management Concrete Washouts are used to contain concrete and liquids when the chutes of concrete mixers and hoppers of concrete pumps are rinsed out after delivery. The washout facilities consolidate solids for easier disposal and prevent runoff of li quids. The wash water is alkaline and contains high levels of chromium, which can leach into the ground and contaminate gr oundwater. It can also migrate to a storm drain, which can increase the pH of area waters and harm aquatic life. Solids that are improperly disposed of can clog storm drai n pipes and cause floodi ng. Installing concrete washout facilities not only prevents pollution but also is a matter of good housekeeping at your construction site.

General Construction Site Wastes must be properly managed and di sposed of to reduce the risk of pollution from materials such as surplus or refuse building materials or hazardous wastes. Practices such as trash disposal, recycling, proper ma terial handling, and spill prevention and cleanup measures can reduce the potential for stormwater runoff to mobilize construction site wastes and contaminate surface or ground water. Handle all solid wastes, hazardous materials and wastes, pesticides and fertilizers, petroleum products and detergents accordingly. The only way to be sure that waste management practices ar e being followed is to be aware of worker habits and to inspect storage areas regularly.

Spill Prevention and Control Plans (SPCP) should clearly state measures to stop the source of a spill, contain the spill, clean up the spill, dispose of contaminated material s, and train personnel to prevent and control future spills. SPCPs are applicable to construc tion sites where hazardous wastes are stored or used. Hazardous wastes include pe sticides, paints, cleaners, petroleum products, fertilizers, and solvents. Make equipment and ma terials for cleanup readily accessible, and mark them clearly so workers can follow procedures quickly and effectively. A SPCP can be highly effective at reducing the risk of su rface and ground wate r contamination.

Vehicle Maintenance and Washing occurs in garages and wash facilities, not usually at construction sites. If these activities must occu r onsite, operators should follow appropriate BMPs to prevent untreated wastewater or hazardous wast es from being discharged to surface or ground waters. Vehicle maintenance and washing BMPs pr event construction site spills of wash water, fuel, or coolant from contaminating surface or ground water. Using a covered, paved area for washing, ensuring that areas are properly connecte d to a storm drain system, and properly handling and disposing of vehicle wastes and wash water should all be taken into consideration when implementing this BMP. These techniques effect ively reduce discharges of untreated automotive wastes and wash water to receiving waters.

4.4 PHYSICAL RESOURCES

4.4.1 E ARTH R ESOURCES Constructing a building or facility involves a variety of activities, including the use of equipment that alters the site’s environm ental conditions. Constr uction activities typica lly involve excavating and clearing existing vegetation, top soil removal, re-grading, and draina ge pattern alterations. Pollutants associated with C& D industry stormwater discharg es can adversely affect the environment in a number of ways. Potential effect s include impairment of water quality, destruction of aquatic life habitats, and enlargement of floodplains. Soil and groundwater disturbance canConstruction and Development NPDES Ge neral Permit Environmental Assessment

53 mobilize pollutants alre ady present on a C&D site due to a broad range of human activities and land uses that can contaminate a si te’s soil and groundwater.

 Industrial activities can directly deposit a wide range of pollutants in soil and groundwater, including metals, nutrients, and toxic organi c compounds (Folkes et al. 2001; Seattle and King County Public Health 2001; Area Wide So il Contamination Task Force 2003; Blanco et al. 2009).

 Agricultural lands can contain el evated levels of pesticide resi dues, nutrients from fertilizers and manure (particularly phosphorus), and salts from irrigation waters (New Jersey DEP 1999; Area Wide Soil Contamination Task Force 2003; Renshaw et al. 2006; Robinson et al. 2007; Stone and Anderson 2009) and constitu te a large (approximately 40%) portion of currently developed land (NRC 2008).

 In urban areas, construction often begins w ith demolition and removal of existing buildings and other structures. Materials in pres erved wood (e.g., creosote, chromated copperarsenate); paint chips and dust (including l ead-based paints); brick and wood scraps; concrete debris; asbestos-based insulation a nd other materials; polychlorinated biphenyls (PCBs) from old electricity transformers; metal scrap; waste solvents; historic fuel spills; and fill material composed of coal ash and clinkers, brick and concrete demolition debris, and other industrial by-products may be present (Blanco et al . 2009). Pesticides have been widely used in urban areas, as well, and re sidues may persist in soil and other materials (Folkes et al. 2001). Erosion and leachate from these materials may elevate pH, metals, and toxic organic compounds levels in stormwater runoff.

 Atmospheric deposition is a source for several contaminants, including metals (e.g., copper, chromium, lead, mercury, and zinc), nutri ents (nitrogen, phosphorus), and organic compounds (e.g., PAHs, PCBs, and pesticides). These contaminants are generated by both stationary and mobile sources, e.g., smelters, power plants, mo tor vehicles, and wind-borne dusts (Folkes et al. 2001; NRC 2008). Although atmospheric deposition from such sources is more likely to occur downwind near urbani zed areas, atmospheric de position can be very widespread and affect undevelope d areas (e.g., undisturbed forest ). Atmospheric deposits of persistent pollutants may accumulate to significant levels (Seattle and King County Public Health 2001, Area Wide Soil Cont amination Task Force 2003), e.g., from leaded fuels that have elevated lead levels in many urban soils. In addition to adverse physical effects of sediment ation, sediments are associated with a variety of other types of pollutants. Stor mwater runoff from cleared and exposed areas may also contain hazardous contaminants or pollutants, whether natu rally occurring or from previous land use, can increase pollutant transport to surrounding waterbodies. For exam ple, nitrogen and phosphorus are common, sediment-associated soil constituents that can also pollute receiving waters as excess nutrients. Other pollutants come from construction equipment a nd materials or from historic contamination at construction sites. These pollutants include metals , trash and debris, nutrients, organic matter, pesticides, petroleum hydrocar bons, polycyclic aromatic hydro carbons (PAHs) and other toxic organics, and pathogens (USEPA 20 09a). Construction activity can also affect receiving waters by increasing the volume and intensity of stormwat er runoff from a site. These flows can erode receiving water banks and beds, particularly when pipes, ditches, or othe r stormwater conveyances concentrate discharges. Surface water erosi on can alter waterbody morphology and elevate sediment and turbidity leve ls downstream (USEPA, 2009b).Construction and Development NPDES Ge neral Permit Environmental Assessment

54 Different land uses produce differing levels of sediment loads to watersheds. Forested watersheds in the US are estimated to yield 0.02 tons to 1 ton se diment/acre/year. Cropland in the US is estimated to yield 15- to 30-fold higher sedimentati on rates, ranging from 0.65 tons to 15 tons sediment/acre/year (Vice et al. 1969; Yorke and He rb 1978; Osterkamp et al . 1998; Faucette et al. 2007). C&D activity generally increases sedimentati on 100- to 10,00-fold grea ter than forested areas, with reported sediment yields of 0.009 tons to 219 tons sediment/acre/year from catchments containing construction (Paul and Meyer 2001). All studies of construction site sediment yield report that construction activity increases sediment discharges from sites. Because of the importance of precipitation and its s ubsequent flow over land to the transport of soil, most sediment and turbidity discharges take place during or shortly after precipitation events. Once a precipitation event ceases, discharges from cons truction sites generally cease within a relatively short time period unless site terr ain or stormwater management sy stems, such as stormwater ponds, attenuate discharge flows. This dynamic creates an intermittent discharge of pollutants from most construction sites. During the construction period, the affected land is usually strippe d and the soil compacted, leading to the potential for increased stormwater runoff and high rates of erosion. If the exposed areas contain either naturally occurr ing hazardous contaminants or pollutants from previous land uses, pollutants can be carried at increased rates to surrounding waterbodies by stormwater runoff. Although the cleared construction site is only a temporary condition (usually lasting less than 6 months), the landscape is permanently altered even after the land has been restored by replanting vegetation due to the intrinsi c nature of development. Vegetation plays such an important part in erosion cont rol that re-vegetati on is an important, n effective stormwater/erosion mitigation techniqu e. Vegetative stabilization measures employ plantings to protect soil exposed to the erosive forces of water and wind. Selected vegetation can reduce erosion by more than 90 percent (Fifield 1999b). Natural plant communities that are adapted to the site provide a self-maintaini ng cover that is less expensive than structural alternatives. Plants provide erosion protection to vul nerable surfaces (Heyer no date) by:

• Protecting soil surface from the impact of raindrops

• Holding soil particles in place

• 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 abra sive transported materials

• Causing sediment deposition that reduces sediment load and reestablishes the stream bank.

4.4.2 W ATER R ESOURCES C&D activities can generate a br oad range of environmental impact s by introducing new sources of contamination and by altering the physical characteri stics of the affected la nd area. These activities can result in both short- and long-term adverse e ffects on surface water quality in streams, rivers, and lakes in the affected watershed by increasi ng the loads of various po llutants in receiving waterbodies, including sediments, metals, or ganic compounds, pathogens, and nutrients. Ground water also can be adversely aff ected through diminished recharge capacity. Other potential effects include the physical alteration of ex isting streams and rivers due to the excessive flow and velocity of stormwater runoff (USEPA 2009a).Construction and Development NPDES Ge neral Permit Environmental Assessment

55 Precipitation events are the primary cause of constr uction site sediment and turbidity discharges to surface waters. Raindrop impact energy and overland water flow detach soil particles from the land surface, suspend them in surface flow, and transport them to other locations on the construction site or to discharge points. Suspended soil partic les in the stormwater flow create turbidity. Construction sites discharge sediment and turb idity to all major surface water categories —lakes, reservoirs, ponds, and other impoundments; streams a nd rivers; wetlands and estuaries; and bays and other coastal waters. Some wa terbodies have flow regimes and physical structures that allow them to purge or absorb excess sediment and turb idity inputs within relatively short time frames. Other surface water regimes allow excess sediment a nd turbidity to persist for long periods of time. The ability of individual surface waters to transp ort sediment varies as precipitation and other factors modify the nature of their flow. Surface wate rs also vary widely in their size relative to construction site discharges. Larg er surface waters generally have more capacity for dilution of soluble pollutant discharges and dispersion of pa rticulate and particulate- associated pollutants. Sediment and turbidity movement within surface waters is highl y variable. Factors influencing sediment and turbidity movement and persistence in surface waters include the intensity, quantity, and composition of sediment and turbidity discha rges and the nature of the receiving waters. Important waterbody characteristics in clude type, size, and flow rate. Sediments and turbidity migrate with surface wate r flow downstream and, therefore, can affect waters beyond the initial receiving water. Migration of construction sediment typically benefits the initial receiving water but impacts downstream waters. Several studies have documented improvements in stream conditions once construction site sediment and turbidity discharges cease and accumulated sediments migrate downstream from the initial point of entry. The sediments, however, remain within the su rface water network a nd are redistributed to new waterbodies downstream. Because of sediment’s ability to persist and migrate downstream, surface waters downstream of a watershed containi ng a consistent level of construc tion activity from year to year can experience a relatively consis tent level of impact from cons truction sediment and turbidity discharges, even though the timing of individual precipitation events and the locations of individual construction sites within the waters hed change from year to year. The degree to which soil particle s remain suspended helps to dete rmine the degree to which it will be able to move with water flow within a surface water or whether it will be deposited on a surface water bed. It also determines whether or not a sediment particle will contribute to surface water turbidity, since only suspended par ticles increase turbid ity levels. Particles smaller than 0.063 mm (silt and clay) tend to remain suspended in fl owing freshwater systems and are the primary contributors to water turbidity (USEPA 2009b).
4.4.2.1 Freshwater Ecosystems The transport and fate of mobilized sediment depe nds on the flow characteristics of the receiving water and the settling ch aracteristics of the sediment, a nd the most fundamental physical characteristic of sediments is their settling velocity. Lake, pond, a nd reservoir flow environments more closely approximate the still-water c onditions under which Stokes’ law (USEPA 2009b) applies to sediment particles to predict settling velocit y. The assumption of Stokes-type settling is often used to predict the rate of sedimentation by co mparing the time required for a particle to settle with the particle’s transit time through the waterbody. Several surface water characteristics influence settling and transit times, including size , shape, depth, and regulation of outflow (USEPA 2009b) and these characteristics vary widely among lakes, ponds, and reservoirs.Construction and Development NPDES Ge neral Permit Environmental Assessment

56 Streams and rivers have a strong, primarily unidirectional flow as a distinguishing characteristic. Stream and river sediment transport is predomin antly controlled by stream transport capacity, and the sediment physiochemical charac teristics and supply ra te. Larger sediments generally experience more episodic movement over longer time scales through watersheds. Smaller sediments generally move more continuously and w ithin a shorter time scale. Sediments transported by rivers and streams are t ypically described as bed load and suspended load. The boundary separating these categories changes w ith flow conditions. Sediments not in transport at a given time are often referred to as bedde d sediments. If flow conditions change, these sediments can become bed load or suspended lo ad. Sediment particle size is the primary distinguishing factor among these categories, wi th the largest partic les deposited as bedded sediments, larger particles moving as bed load, a nd finer particles moving as suspended load. Total sediment load consists of the sum of bed load and suspended load (USEPA 2009b) The variation in soil types found in the United States is a significan t factor in estimating sediment discharges. EPA used soil coverage data prov ided in the State Soil Geographic Database (STATSGO) (Wolock 1997; USDA 2007) and the CONU S-SOIL data layers (Miller and White 1998) for the loadings analysis. STATSGO compone nt and layer tables were accessed through the Pennsylvania State University’s active archive (http://www.soilinfo.psu.edu/index.cgi?soil_data &index.html). EPA extracted data for only the portions of RF1 watersheds where development change has been documented by NLCD. EPA used an urbanization change mask to create RF1 waters hed parameter values. The geographic limits of the soil coverage evaluated were determined by superimposing indicator city urban area boundaries—from the U.S. Census Bureau’s 2000 Urbanized Areas Cartogr aphic Boundary Files (U.S. Census Bureau 2000)—on intersecting RF1 watersheds. The resulting list of RF1 watersheds intersecting the rapidly developing indi cator city urban areas was used to spatially identify underlying STATS GO soil coverage Map Unit Identifiers (MUIDs). Soil data associated with the surface soil layer wi thin the selected MUIDs were extracted from STATSGO to produce the suite of data evaluated for each indicator city. EPA also used GIS data to determine the percentage of each hydrologic soil group (HSG) for each RF1 watershed using the urban masking approach. The percentages for RF 1 HSGs were then used to estimate runoff coefficients for each RF1 wa tershed (USEPA 2009a). EPA (waters ( http://www.epa.gov/wa ters/ir/index.htm ) also performed a set of analyses using the Assessment TMDL Tracking and Implementation System (ATTAINS) to assess the relative contribution of sediment and turbidity as causes of impairment in impaired rivers and streams, lakes and reservoirs, and bay and estuaries. Of the approximately 935,120 total river and stream reach miles analyzed, 458,209 miles (49%) have been iden tified as impaired. Sedi ment contributes to impairment in 107,231 miles (23%) of impaired rive r and stream waters; tu rbidity/suspended solids contribute to impairment in 26,278 miles (5.7%) of im paired river and stream waters. For lakes and reservoirs, of the approximate total 17,492,935 acres analyzed, 11,545,337 acres (66%) are identified as impaired. Sediment contribu tes to impairment in 715,558 lake acres (6.2%); turbidity/suspended solids cont ribute to impairment in 1,008,276 acres (8.7%). For bays and estuaries, of the approximat e total 11,400,127 acres analyzed 7,182,080 acres (63%) are identified as impaired. Sediment contributes to impair ment in 133,760 acres (1.9%) of impaired bay and estuary waters; turbidity /suspended solids contribute to im pairment in 153,699 acres (2.1%) of impaired bay and estuary waters.Construction and Development NPDES Ge neral Permit Environmental Assessment

57 EPA assessed changes in water quality for the C& D Rule using the U.S. Geological Survey’s SPARROW modeling (Spa tially Referenced Regressions on Waters hed attributes). For the analysis described in EPA 2009b, SPARROW was used to evaluate the effectiv eness of a range of regulatory options for controlling construction related runoff and improving water quality as measured by in-stream Total Suspended Solids (TSS), TN and TP concentrations. SPARROW models for the conterminous United States for sediment, nitrogen, and phosphorus were used to characterize baseline water quality conditions. EPA performed extensive SPARROW modeling fo r total suspended sediment (TSS) and the nutrients total nitrogen (TN) and total phosphorus (TP) for the conterminous US, described in Schwarz (2008a). EPA’s approach relied on empiri cal relationships between baseline in-stream TSS/TN and TSS/TP concentrations to derive es timates of the post-compliance nutrient reductions. The TSS analysis was based on mass flux estimates compiled from more than 1,800 long-term monitoring stations operated by the USGS during the period 1975-2007. SPARROW modeling is structured on the RF1 stream network, consis ting of approximately 62,000 reach segments and more than 4,000 reservoirs. The model identifies six sources of sediment , including the stream channel and five classes of land use (urban, forest ed, federal non-forested, agricultural and other). Table 4-2 presents the results, which show, per unit ar ea, Federal non-forested and urban lands are the largest landform sediment sources.
Table 4-2. Estimation Results for the SPARROW Suspended Sediment Model

Parameter Units Estimate Standard Error

Federal Non-forested land
Urban land Agricultural land
Other land
Forested Land Streambed (reach length) kg/km 2 /yr kg/km 2 /yr kg/km 2 /yr kg/km 2 /yr kg/km 2 /yr

kg/m/yr 64,344 47,130 18,047 11,343

634

28.80 12,411 9,925 3,623 3,186

898

6.40 Source: Schwarz as reported in EPA 2009b Reducing soil erosion and sedime nt runoff from construction s ites not only reduces sediment loadings into streams, but can also reduce concentr ation of other pollutants that are present in the soil. To evaluate the water quality benefits of these ancillary reductions, EPA developed an approach that relies on the empi rical relationship observed between baseline in-stream suspended sediment concentrations and Total Nitrogen (TN) and Total Phosphorous (TP) concentrations to derive estimates of the post -compliance nutrient reductions. USGS developed SPARROW models for TN and TP transport for the non-tidal conterminous United States as described in Smith et al. (1997). Observed TN and TP transport rates were derived from water-quality records for 414 stations in the National Stream Quality Accounting Network. Nutrient sources identified in the regression e quations include point sour ces, applied fertilizer, livestock waste, nonagricultural land, and (f or TN only) atmospheric deposition. Surface characteristics found to be significant predictors of land-water delivery include soil permeability, stream density, and (for TN only) air temperature. The nutrient/TSS ratio was calculated using SPA RROW model outputs of TSS, TN, and TP mass flux related to land-based runoff for the baseli ne conditions; ratios were calculated for eachConstruction and Development NPDES Ge neral Permit Environmental Assessment

58 individual reach. EPA averaged the reach-level ratios to the HUC8 watershed level to obtain a nutrient-to-sediment ratio that represents the av erage relationship between in-stream nutrients and suspended sediments within each basin. EPA later us es these watershed-average ratios to estimate reach-specific changes in suspended sediment con centrations for each scenario to yield estimated reach-level changes in nutrient concentration. EPA also estimated impacts on waterbody TSS levels using SPARROW. Table 4-3 summarizes sediment loadings for current CGP and proposed CGP scenarios based on the national baseline annual estimated sediment loading of 2,580,000 t ons, the estimated current CGP estimated sediment loadings (based on the current CGP’ s 4.6% share of national C&D activity), and the projected sediment loadings of the proposed CG P that incorporates the C&D Rule. The proposed CGP is expected to result in a reduction of 40,020 tons, a 34% re duction compared to the current estimated CGP sediment loadings of 118,680.

Table 4-3. Baseline C&D Stormwater Load ing Summary and Post-Compliance Reductions

Analysis Sediment Loading, tons Sediment Reduction, tons Percentage Reduction from Current CGP

Current CGP 118,680

Proposed CGP 78,660 40,020 34%

Source: total US baseline sediment loadings (2,580,000 tons) and total US reach miles post-compliance BAT/NSPS, sediment loadings (600,000 tons), EPA 2009b

Table 4-4 summarizes national average reach-length we ighted TSS concentrations in RF1 reaches as estimated by SPARROW under the C&D Rule and the pre- and post- proposed CGP scenarios. Information is presented for all reaches in the RF1 network that receive sediment loading from construction sites. Table 4-4 also presents information on the di stribution of TSS concentrations for the median (50th percentile) TSS concentrati on for the current CGP ( 289.3 mg/L) and proposed CGP (288.6 mg/L, for a decrease of 0.7 mg/L).

Table 4-4. Distribution of TSS Concentration based on SPARROW Output for RF1 Reaches Receiving C&D Stormwater Discharges

Scope of Analysis Reach Count Reach Miles Modeled Average TSS (mg/L) 1 Reduction in Average TSS (mg/L) 1 Median TSS Concentration (mg/L) 1 Reduction in Median TSS

(mg/L) 1

Current CGP 1,469 18,955 956.4 - 289.3 -

Proposed CGP 1,469 18,955 955.0 1.5 288.6 0.7

1. Reach length-weighted Source: total US baseline reach count (31, 927) and reach miles modeled (412,062 mi), EPA 2009b

Table 4-5 describes the number of RF1 reach m iles improved and the distribution of TSS concentration reductions for the proposed CGP relative to the current CGP TSS. Table 4-5Construction and Development NPDES Ge neral Permit Environmental Assessment

59 summarizes projected sediment reduc tion in terms of reach miles improved at various levels of TSS reduction for the current CGP and proposed CGP. Proposed CGP issuance improvements in TSS concentrations of > 50 mg/L are projected for 16 reach miles; improvements of 10-50 mg/L are projected for 84 reach miles; improvements of 5 - 10 mg/L are projected for 138 reach miles; improvements of 1 -5 mg/L are projected for 1,087 reach miles; improvements of 0 -1 mg/L are projected for 16,632 reach miles; reach miles with improved TSS concentrations total 17,957 miles.

In evaluating these improvements, however, SPARR OW modeling of the reduc tion in loadings and concentrations in reaches that receive constructi on sediment discharge directly does not account for the decreased loadings and concentrations in down stream reaches. The total number of reach miles and degree of improvement that are analyzed and presented in Table 4-5 , therefore, are underestimates. Table 4-6 summarizes average, reach-length we ighted TN and TP concentrations for the current CGP, and the proposed CGP for r eaches receiving C&D sediment discharges. TN and TP concentrations in the RF1 network vary ov er a wide range. The average TN concentration is 18.22 mg/L under the current CGP wh ile for the proposed CGP the TN level decreases 0.01 mg/L to 18.21 mg/L

. The average TP concentration is 3,921.6 mg/L under the current CGP while for the proposed CGP the TN level decreases 5.3 mg/L to 3,916.3 mg/L

.
Table 4-6. Distribution of TN and TP Concentrations Based on SPARROW Output for RF1 Reaches Receiving Direct C&D Stormwater Discharges

Scope of Analysis Reach Count Reach Miles Average TN (mg/L) 1 Reduction in Average TN

(mg/L) 1 Average TP (mg/L) 1 Reduction in Average TP

(mg/L) 1

Current CGP 1,469 18,955 18.22 - 3,921.6 -

Proposed CGP 1,469 18,955 18.21 2 0.02 2 3,916.3 2 5.3 2

1. Reach-length weighted 2. Rounding of significant numbers may result in inconsistent values within the text and tables. Source: total US baseline reach count (31,927) and reach m iles (412,062 mi), EPA 2009b

Table 4-5. Total RF1 Miles that Receive Direct C&D Loadings with Improvements in TSS Concentrations

Scope of Analysis Total RF1 Miles Total Miles with Reduced TSS 1 Reach Miles Improved

Ranges of Reductions in TSS Concentration (mg/L)

0 - 1 1 – 5 5 - 10 10 - 50 ≥ 50

Current CGP 18,955 17,957 - - - - -

Proposed CGP 18,955 17,957 16,632 1,087 138 84 16

1. Not included in the total are 40 r eaches (422 reach miles) where SPARR OW did not predict concentrations. The 99.9% fraction represents all reach miles ov er which SPARROW calcula tes TSS concentrations. Source: total US baseline reach miles (412,062) and to tal US post-compliance BAT/NSPS reach miles with reduced TSS (390,374), EPA 2009bConstruction and Development NPDES Ge neral Permit Environmental Assessment

60 Note that these numbers represen t national, CGP-wide concentrati on reductions, and do not reflect the wide geospatial variability in TN and TP c oncentration reductions. Also, changes in nutrient concentrations are based on in-stream sediment reductions. Therefore, the distribution and magnitude of percent change in reach miles will be the same as for TSS (USEPA 2009b)

.
4.4.2.2 Water Quality Index To link water quality changes from reduced sedi ment discharge to effects on human uses and support for aquatic and terrestrial species habitat for the C&D Rule , EPA utilized a water quality index (WQI). The index translates water quality measurements, gathered for multiple parameters that are indicative of various aspects of wate r quality, into a single num erical indicator. The parameters used in formulating the WQI were determined based on waterbody type, scientific understanding of ecosystem response to varying conditions, and available data. The WQI provides the link between pollutant levels and both the pres ence of aquatic species and the suitability for particular recreational uses. The WQI value is measured on a scale from 0 to 100 and reflects water quality ranging from 0 for poor quali ty to 100 for excellent quality. To support the analysis of changes in sediment load ings from construction s ites relative to baseline conditions, EPA adapted Cude’s (Cude 2001) me thodology to a national s cale by developing subindex curves for TSS at the level of ecoregions . EPA also further modified the WQI methodology to apply to estuarine reaches, building on prior applications of WQI concepts to saltwater environments (Harrison et al . 2000; Canadian Council of Mini sters of the Environment 2001; Carruthers and Wazniak 2003; Gupta et al. 2003; and USEPA 2007a). EPA implemented the WQI methodology by using th ree key steps: (1) obt aining water quality measurements for each parameter included in th e WQI; (2) transforming measurements to subindex values expressed on a common scale; a nd (3) weighting and aggregating the individual parameter sub-indices to obtain an overall WQI value that reflects waterbody conditions across the parameters. These steps are described in full in EPA 2009b. The freshwater WQI used by EPA to evaluate water quality in rivers and streams incl uded six parameters selected to represent major stream impairment categories: dissolved oxyge n (DO), biochemical oxygen demand (BOD), fecal coliform (FC), total nitrogen (TN), total phosphor us (TP), and total suspended solids (TSS). The estuarine WQI included parameters that are common to both freshwater and saltwater systems— dissolved oxygen, nitrogen, phosphorus, fecal coliform, and suspended solids—and replaced biochemical oxygen demand with chlor ophyll-a (ChA). ChA is a measure of amount of phytoplankton present in the waterbody. While phytoplankton are a natural component of a waterbody’s food web, changes in its abundan ce (e.g., high ChA), species composition, and productivity are commonly the first biological re sponse to nutrient enrichment (Chesapeake Bay Program 2008, as cited in EPA 2009b). Subseq uent decomposition of the phytoplankton may reduce available dissolved oxygen and induce hypoxia and anoxia. Baseline freshwater WQI values are based on ba seline data for 60,017 reaches in the coterminous United States. Baseline concentrations for all WQ I parameters were avai lable for a total of 9,444 reaches. EPA used a successive average approach to address the data gaps in the remaining freshwater reaches. For estuaries and coastal reaches, EPA used a similar approach to estimate missing concentration values based on the average concentrations available for reaches within consecutively coarser HUC levels. Due to the sma ller scale of estuarine wa terbodies, EPA used theConstruction and Development NPDES Ge neral Permit Environmental Assessment

61 average of concentration values for HUC8, HU C6, and HUC 4 to estimate average parameter concentrations for reaches where data gaps existed and did not estimate values based on HUC2
averages. Each RF1 reach that had an improved WQI value re lative to its baseline WQI value contributed to estimated economic benefits. Base d on the estimated WQI value unde r the baseline scenario, EPA categorized each RF1 reach using four WQI ranges (WQI < 25, 25 ≤ WQI<50, 50 ≤ WQI<70, and 70 ≤ WQI). WQI values of less than 25 indicate that wa ter is not suitable for boating (the recreational use with the lowest required WQI), whereas WQI values greater than 70 indicate that waters are swimmable (the recreational use with the highe st required WQI). For eac h WQI category under the baseline scenario, EPA estimated the weighted average WQI using reach miles as weights. The difference in WQI between baseline c onditions and CGP-re lated conditions ( Δ WQI) is a measure of the change in wate r quality. To monetize benefits of the regulation, EPA used three ranges of water quality improvements 0.01< Δ WQI ≤ 0.1, 0.1 < Δ WQI ≤ 0.5, and 0.5 < Δ WQI). For each baseline water quality cate gory and improvement range combination, EPA estimated the
average Δ WQI and the corresponding percenta ge of total reach miles. In this analysis, the numbers of reach miles im proved, .i.e., that experience a change in the WQI value, differ from the numbers presented in Se ction 4.4.2.1, which used absolute changes in TSS, TN, or TP concentrations. An additional differen ce is that the data pres ented cover all reaches within the RF1 network, including those that do not receive construc tion discharge directly but may nevertheless see improvement due to changes in water quality in upstream reaches. Changes in water quality under the current CGP and the proposed CGP are presented in Table 4-7.

4.4.2.3 Human Use

Ultimately, changes in sediment and other pollutant loadings from construction sites related to the final regulation affect humans through influences on the production of goods a nd services that enter into individuals’ utility functions. Table 4-8 summarizes some of the important ways in which sediment and other pollutant disc harges from construction sites a ffect the quantity and quality of services provided by the natural environment a nd how these services in turn provide economic value to society through various use and nonuse related societal welfare mechanisms. Underlying this table is a conceptual framework based on th e valuation of ecosystem services (Daily 1997; Simpson and Christensen 1997; va n Houtven et al. 2005, as cited in EPA 2009b). EPA was not able to bring the same depth of analysis to a ll of the environmental services affected by the regulation categories, however, because of imperfect understanding of the link between discharge Table 4-7. Estimated Pre-Proposed CGP and Post-Proposed CGP Water Quality Improvements

Scope of Analysis Baseline Scenario, Total Reach Miles Modeled 0.01< Δ WQI ≤ 0.1 0.1 < Δ WQI ≤ 0.5 0.5 < Δ WQI Total Improved Reaches

Reach Miles Reach Miles Reach Miles Reach Miles

Current CGP 28,873 - - - -

Proposed

CGP 28,873 2,773 449 139 3,361

Source: total US baseline total reach miles modeled (650 ,043) and total reach m iles modeled (627,679), EPA, 2009bConstruction and Development NPDES Ge neral Permit Environmental Assessment

62 reductions and benefit categories, and how society values some of the benefit events. EPA was able to quantify and monetize some benefits (including maintenance to navigabl e waterways, reservoir dredging, drinking water treatment, and WTP for im provements in large river and streams and some coastal waters), quantify but not monetize other benefits (changes in pollutant concentrations in lakes), and assess still other bene fits only qualitatively (e.g., commercial fish ing, flood damages, and property values) (EPA 2009b).

Table 4-8. Summary of Benefits from Reducing Se diment and Other Pollutants in Stormwater Discharges from C&D Sites

Activity Environmental Service Flows Potentially Affected by Discharges from Construction Sites Entities Affected by Environmental Changes Methods Used in EPA’s Analysis of Benefits from the Regulation Firms Governments Individuals

Recreation:

Outings, boating, swimming, fishing Aesthetics, water clarity, water safety, degree of sedimentation, eutrophication, weed growth, fish and shellfish populations Y Use & Nonuse Values Benefits Transfer

Commercial fishing and shellfishing Fish and shellfish populations Y Y Use & Nonuse Values Qualitative Discussion

Property ownership Aesthetics, safety of property from flooding, property value Y Y Use & Nonuse Values Benefits Transfer

Water conveyance and supply; Water storage;

Water treatment Turbidity, degree of sedimentation Y Y Use Values Avoided cost to governments,

including:

Reservoir dredging,

Drinking water
treatment

Water Transportation Degree of sedimentation of navigational channels, harbors, and other waterways Y Y Use Values Avoided cost to firms and governments

Water use: industrial, municipal, agricultural Turbidity Y Y Use Values Qualitative Discussion

Knowledge (no direct uses) Environmental health Nonuse Benefits Transfer

Source: EPA 2009b

Transportation Implementation of the regulation is expected to result in less frequent dredging of navigable waterways due to reduced sediment runoff from cons truction sites. This will result in avoided costs to the government and private entities respons ible for maintenance of navigational shippingConstruction and Development NPDES Ge neral Permit Environmental Assessment

63 channels, harbors, rivers, and other wate rways (EPA 2009b). For th e period 1995–2008, including dredging performed by USACE and dredging contr acted to other firms, USACE funded nearly 3,400 dredging occurrences, worth more than $9 bill ion (2008$). This dredging removed more than 2.6 billion cubic yards of sediment from more than 1,100 navigable reaches (EPA 2009b). Location information provided by USACE Dredging Information System was given by latitude– longitude coordinates for some j obs, but for others, location information was limited to the name of the job (usually the waterway dr edged) and the USACE district that performed the job. To identify the nearest reach segment, EPA used ERF 1.2 (Enha nced Reach File) from USGS. For this analysis, EPA researched latitude/longitude coordinates fo r jobs where they were not provided and linked them to Reach File Version 1.0 (RF1) reaches. E ach latitude/longitude of interest was matched to the nearest point in the ERF 1.2 universe of point s using a spherical model of the earth and a standard haversine distance formula. To associat e the point with an RF1 reach number, EPA used the “RR” (River Reach) attribute from the ERF 1 .2 attribute table. No reach types were excluded from consideration in the nearest reach calculati on. Because these coordinates may be inexact, dredging activity was aggregated to the state level for the calculations in this analysis and is presented at a regional level (EPA 2009b).

EPA assumed that navigable waterways that are re gularly dredged would benefit from reducing the amount of sediment that needs to be dredge d up. Although other waterways may benefit from reduced sedimentation, EPA based its estimation of reduced dredging activity based on historic dredging data from USACE. For dredging jobs that occurred only once between 1995 and 2008, EPA assumed that this job or one similar to it will occur over the same time frame in the future. However, these single occurrence jobs are excluded from the low range estimate of the analysis (EPA 2009b). The total quantity of sediment dredged for each job (single location) over the past 14 years was divided by the number of occurrences of that job to calculate an average quantity of sediment dredged for an occurrence of that job. EPA assu med that this quantity of sediment would be dredged each time the job occurs in the future un der the baseline scenario , and that it would be reduced due to the regulation (EPA 2009b). EPA estimated changes in sediment deposition in navigable waterways un der different regulatory scenarios using output from SPARROW. For the pos t-compliance scenarios, EPA calculated the percentage change in sediment yield from the baseline for each RF1 reach in the SPARROW analysis. The quantity of sediment for each dredgi ng job was multiplied by this percentage change in sediment yield to obtain a post-compliance quanti ty of sediment to be dredged each time a job occurs in the next 14 years (EPA estimated future dredging for 14 years to reflect the 14 years of historic data provided by USACE) . If an RF1 reach was not assigne d to a dredging job due to data limitations or the reach assigned to that dred ging job was not included in the SPARROW model (such as coastal reaches), the state-wide average re duction in sediment yield was applied to that job (EPA 2009b). To account for uncertainty in projecting future dr edging costs, EPA adjusted the assumptions to provide a range of benefits es timates. EPA estimated low, midpoi nt, and high levels of dredging activity for this sensitivity analysis as follows:

 Low estimate:Construction and Development NPDES Ge neral Permit Environmental Assessment

64 ▫ Assuming a minimum recurrence interval (bel ow which occurrences are assumed to be continuations of the previous occurr ence of the same job) of 180 days

▫ Assigning 10th percentile cost and cubic yard s dredged estimates for jobs lacking these data

▫ Excluding jobs with only one occurrence over the 14 years from 1995 to 2008.

 Midpoint estimate:

▫ Assuming a minimum recurrence interval of 90 days to include jobs with more closely spaced recurrences

▫ Using 50th percentile (median) cost and cubi c yards dredged estimates for jobs lacking these data

▫ Including jobs with only one occurrence over the 14 years from 1995 to 2008 under the assumption that these jobs or similar j obs will occur once over the next 14 years.

 High estimate:

▫ Assuming a minimum recurrence interval of 30 days

▫ Using 90th percentile cost and cubic yards dred ged estimates for jobs lacking these data

▫ Including jobs with only one occurren ce between 1995 and 2008 under the assumption that these jobs or similar jobs w ill occur once over the next 14 years. EPA annualized its 14-year dredge projection in orde r to facilitate the comparison of these costs to other costs calculated for the analysis of the re gulation that are measured on an annual time frame (costs associated with sediment re moval are reported in Section 4.5). Table 4-9 presents estimated total annualized dredging (cubic yards removed) for navigable waterway dredging for the current and proposed CGPs. The table provides proj ected low, midpoint, and high estimates. Table 4-9 also presents annualized low, midpoint, and high estim ates of navigable waterways dredging avoided under the proposed CGP. The avoided dredging ac tivity considered the benefit to navigation resulting from the proposed CGP.

Table 4-9. Annualized Navigable Waterw ay Dredging, Pre- and Post-CGP Issuance

Scope of Analysis Total Sediment Dredged (million cubic yards)
Low Midpoint High

Current CGP 96.3 120.3 127.9

Proposed CGP 95.9 119.9 127.5

Reduction in Sediment Dredged (million cubic yards)

Proposed CGP 0.4 0.4 0.4
Source: total US baseline low (2,093), midpoint (2,616), and high (2,781) estimated navigable waterways dredging , EPA 2009b

Reservoirs EPA also examined impacts of C&D stormwater discharges on reservoir locations, uses, and historic sedimentation rates. Information is av ailable from the Reservoir Sedimentation Survey Information System (RESIS) database (USGS 2007b) . Formally known as RESISII, this database was initially developed by the USDA Natural Res ources Conservation Servi ce, and was provided to EPA by USGS. The database includes 4,227 sediment ation survey results from 1,818 reservoirsConstruction and Development NPDES Ge neral Permit Environmental Assessment

65 located across the conterminous US. Results from 1775 to 1992 are represented, with the majority of measurements covering the mid-20th century and later. RESIS does not include all US reservoirs, nor does it contain info rmation about dredging activity in reservoirs or about any other methods for recapturing lost water storage capacit y. RESIS documents the total sediment deposition per reservoir is more than 1,360,252 tons annually (EPA 2009b). C&D stormwater discharges affect not only sediment concentrati ons in receiving water bodies, but also affect the amount of sedimentation occurrin g in reservoirs. EPA estimated annual sediment attenuation rates in each reservoir using output da ta from SPARROW modeling for all reservoirs on reaches modeled by SPARROW. The amount of sedime nt settling in reservoirs is the basis for estimating the quantity of sediment dredged from reservoirs and th e cost of this dredging (EPA 2009b). The difference between estimated dredging under the current CGP and projected dredging under the proposed CGP provides the benefit attributed to the propos ed CGP from the reduction in dredging activity. Table 4-10 presents current CGP and proposed CGP dredging and projected reductions in dredging. For more than 4,000 reser voirs distributed throughout the RF1 network, SPARROW modeling estimated more than 444 m illion cubic yards accumulate annually under C&D Rule baseline conditions (EPA 2009b). Relative to the pre-CGP issuance reservoir sedimentation baseline of 20.4 million cubic yards, post-CGP issuance reservoir sedimentation is reduced 25,723 cubic yards.

Table 4-10. Estimated Sediment Removed by Reservoir Dredging Under the Baseline Scenario and CGP-related Reductions

Scope of Analysis Baseline Sediment Dredged (yd 3 )

Current CGP 20,451,885
Proposed CGP 20,426,162
Estimated Reduction (yd 3 ) 25,723

Drinking Water Drinking water treatment plants pr ovide the essential services of removing contaminants from water taken from surface and ground sources, making the water potable. Sediment is one of the contaminants that must be removed from drinking water before it can be consumed, so a reduction in sediment levels in water take n up by drinking water treatment plan ts is expected to result in lower treatment costs for these plants (cf. Boardman et al. 2001). The primary concern of sediment in terms of dri nking water treatment is the turbidity that results from suspended sediment in the water column. As turbidity increases in drinking water influent, the variable costs of water treatment to mitigate this turbidity increase.

EPA modeled sediment concentrations in RF1 stream reaches under both the current and final scenarios using the SPARROW model. Drinking wate r treatment facilities located on waterbodies with typically higher levels of TSS and turbidity may have systems in place that reduce total suspended solids and turbidity levels in influent water before it is chemically treated. EPA assumed, as per Ngo and Nichols (1998), that facilities with baseline TSS concentrations exceeding 1,000 mg/L would employ a process such as plain sedime ntation, during which infl uent water is allowed to settle for extended periods of days or weeks. The effectiveness of this process depends on the size of the sedimentation basin and the amount of time the water is left to settle. Studies by YaoConstruction and Development NPDES Ge neral Permit Environmental Assessment

66 (1973) and DeZuane (1997) suggest that the effec tiveness of plain sedimentation ranges from 30 and 90% with a midpoint estimate of 60%. Thus , EPA varied the effectiveness of plain sedimentation basins between 90, 60, and 30% T SS removal for the low, mid, and high benefit estimates, respectively. The more ef fective the plain sedimentation process, the lower the treatment costs to the affected facilities, and consequentl y, the lower their potential savings from reduced influent turbidity (USEPA 2009b). This reduction is applied to influent water TSS concen trations at facilities that are estimated to have influent water with TSS concentrations exceeding 1,000 mg/L in the baseline. Table 4-11 presents the low, midpoint, and high estimates of treated turbidity under the baseline scenario and the current CGP, and under the proposed CGP, as well as the projected reducti on of treated turbidity under the proposed CCP.

Table 4-11. Drinking Water Turbidity Under the Baseline Scenario and Reduction of Drinking Water Turbidity Under Option 1 and Option 4

Scope of Analysis Average Treated Turbidity (NTU)
Low Midpoint High

Current CGP 104.0 205.9 486.0
Proposed CGP 103.8 205.5 485.1
Reduction in Treated Turbidity (NTU 0.2 0.4 0.9

Source : : total US estimated baseline and post-compliance BAT/NSPS low (2,093), midpoint (2,616), and high (2,781) average treated turbidity, EPA 2009b

Recreation EPA did not quantify direct impacts of this rule to recreational uses. However, removal of sediment deposited within navigable waterways or decreasi ng turbidity in reservoi rs and drinking water inherently increases the recreati onal use of streams, rivers, reservoirs, lakes, bottomlands, and estuaries. Table 4-11 through 4-13 provide the reduction in sedime ntation and turbidity and that would directly impact the recreational use of waterways within the United States. Sediment and other discharges fr om construction sites can directly impact reproduction and survival of aquatic species. Impacts to aq uatic species can have a profound effect on subsistence anglers, commercial anglers, and consumers, as well as recreational anglers.

4.4.3 C UMULATIVE I MPACTS The above discussion of impacts of the proposed re-issuance of the CG P on physical resources intrinsically addresses cumulative impacts for several reasons. As the Federal action of issuing a new source NPDES permit, a general permit explic itly addresses cumulative impacts by evaluating impacts, costs, and benefits at the Agency’s best estimate of projected industry activity that will occur under the proposed general pe rmit. Thus, the discussions pres ented above fully anticipate and specifically include analyses at the sum total projected level of C&D activity that EPA expects under the proposed CGP. In developing the proposed CGP, EPA has addresse d the entire span of C& D industry activity, i.e., from the level of individual si tes to aggregated industry activit y at the national level. Also, by addressing sediment and nutrient loadings for stream s, rivers, lakes and estuaries from individual waterbodies to a national level, EPA also has addressed the entir e span of environments mostConstruction and Development NPDES Ge neral Permit Environmental Assessment

67 affected by stormwater discharges form C&D si tes. EPA modeled 31,927 RF1 reach segments, and more than 1,819 reservoirs to determine reduction of sediment, TSS, and nutrient loadings from construction activity. EPA also used background da ta from 729 estuaries and modeled for TSS loadings for 43 estuaries to calculate Wa ter Quality Index values for estuaries. Furthermore, EPA has addressed individual site-speci fic concerns by incorporating specific features into the permitting process. Also, when a NOI is received, designated EPA regional contacts are notified of the application so they can review the individual C&D site activity if needed. By incorporating such protections into the NOI pr ocess, EPA has ensured “no significant cumulative effect” will occur because the process for obtaining coverage has been developed with specific, appropriate, conditions and requirements that anticipate the cons equences of multiple C&D sites as each individual application is received and reviewed.

4.5 BIOLOGICAL RESOURCES EPA provided a qualitative approach to effects of construction site stormwater runoff on biological resources and reviewed the literature to identify potential effects to biological resources. Any removal of “non-natural” sedimentation and turbid ity will benefit the aquatic environment. A variety of organisms, including a quatic plants, invertebra tes, amphibians, and fish, are affected by elevated sediment and turbidity levels. High levels of sediment and turbid ity reduce photosynthetic activity and food availability, bury habitat, direct ly harm organisms, and alter the composition of the aquatic community. Naturally occurring levels of se diment or turbidity vary from waterbody to waterbody. Some aquatic ecosystems are adapted to higher levels of sediment or turbidity (e.g., some large coastal floodplain rivers), whereas other ecosystems are adap ted to lower levels of sediment or turbidity (e.g., alpine lakes, headwater stre ams). Short-term increases in suspended sediment and turbidity levels can naturally occur during spring thaws, storms, and other high flow events. Both the magnitude and duration of sediment a nd turbidity exposure are important. Because organisms vary in their ability to to lerate and recover from exposure proportion of sensitive species declines in waterbodies aff ected by increased sedime ntation and turbidity. However, even organisms adapted to relatively high sediment or turbidity can be harmed by significantly higher levels of sediment and turbidity than that to whic h they have adapted or if their resiliency is taxed by other stressors. Many construction sites have been documented to di scharge other pollutants in addition to sediment and turbidity such as nitrogen, phosphorus, metals , and other organic and inorganic compounds. A number of these other pollutants travel with sediment as it erodes and moves through the surface water network. In addition, many c onstruction sites discharge to su rface waters already impacted by stressors including pollutant discha rges from other sources, invasi ve species, and flow modification. Interactions among sediment, turbidity, and other st ressors and their cumulative effects on aquatic organisms have not been fully characterized (USEPA 2009b). Sediments and turbidity can also affect chemical , fungal, and microbial decomposition processes in aquatic ecosystems. Depending on the source and na ture of the sediments, sedimentation can change the organic content of surface water sediment, which can alter fungal and microbial community activity. Rapid sediment deposition over an organic sediment layer can also cause a shift to anaerobic conditions in the isolated strata and an accompanying shift in microbial metabolism, methane generation, an d nutrient dynamics (USEPA 2009b). In wetlands, depressedConstruction and Development NPDES Ge neral Permit Environmental Assessment

68 levels of algal and microbial biomass and densit y can indicate chronically elevated sedimentation levels (USEPA 2009b).

4.5.1 A QUATIC V EGETATION AND W ILDLIFE R ESOURCES

4.5.1.1 Primary Producers Primary producers transform sunlight into energy and provide food for other aquatic organisms. Primary producers, including algae, phytoplan kton, submerged aquatic vegetation, and other macrophytes (plants with large l eaves), are found in most aquatic ecosystems. Primary producers can grow in a variety of forms: r ooted to surface water substrate, free -floating, or attached to rocks, aquatic plants, or other structures. The term perip hyton refers to the algae, small plants, bacteria, microbes, and detritus attached to subm erged surfaces in aquatic ecosystems. Aquatic ecosystems vary in the degree to which they derive energy and resources from primary producers. For example, some systems are heav ily dependent on the productivity of primary producers (e.g., sea grass beds) while others (e.g., small streams in forested watersheds) derive a large proportion of their energy fr om external sources, such as leaf debris) (USEPA 2009b).

Several studies have indicated th at increased turbidity results in decrease of primary production through light reduction, physical damage and substr ate modification (Kerr et al. 1995). Aquatic macrophytes and algae influence water column chemistry, including dissolved oxygen, pH, and nutrient levels; provide im portant habitat for many organisms; a nd reduce waterbody flow velocity. Loss of algae and macrophytes due to elevated sediment and turbidity levels can compound the effects of these pollutants as fewer plant structur es are available to slow the water flow that facilitates settling of suspende d sediment from the water colu mn. This compounding effect can result in elevated suspended sediment and turb idity levels persisting fu rther downstream (USEPA 2009b).

4.5.1.2 Aquatic Invertebrates Aquatic invertebrates, including zooplankton, insect s, crustaceans, and bivalves (e.g., mussels and clams), are widely distributed am ong aquatic ecosystems and can be found in even the smallest surface waters. They provide an important link in the aquatic food chain between primary producers and larger organisms such as amphibians, re ptiles, fish, birds, and mammals (USEPA 2009b). Because many benthic macroinvertebrates are rela tively stationary and have limited powers to evade polluted waters, their abundance, diversity, and species composition is widely used as an indicator for overall aquatic eco system health (USEPA 2009b).

Increased sedimentation can direct ly and indirectly cause inverteb rate mortality. The effects of elevated sediment and turbidity le vels on invertebrates, particular ly on benthic macroinvertebrates, have been the focus of a large number of st udies over the past several decades. Aquatic invertebrates can be affected by loss of habitat an d inability to feed as well as causing direct mortality. In both freshwater a nd marine ecosystems most macroi nvertebrates are limited by their mobility and any increased sedimentation can imp act their habitat by smothering, changes within substrate composition and their ability to forge for food (Waters 1995; Berry et al. 2003). Changes within the substrate composition can also affect the food source for macr oinvertebrates, while increased turbidity can impede filter feeders abilit y to remove food from the water column (Kerr 1995; Waters 1995). The severity of sediment and turb idity impacts on invertebrate populati ons is related to the intensity and duration of exposure (USEPA 2009b). If dist urbance to a macroinvertebrate community isConstruction and Development NPDES Ge neral Permit Environmental Assessment

69 intense enough, it may impact the ability of th e community to recover its former condition, particularly if sensitive organisms are eliminated from surrounding areas, as well, or habitat has been modified to the point where it is no longe r able to support the fo rmer community (USEPA 2009b). Healthy invertebrate populations in unaffected parts of a surface water system can provide organisms to re-colonize disturbed areas once construction activity ha s ceased (USEPA 2009b).

4.5.1.3 Fishes Both freshwater and marine/estuari ne fishes can be affected by suspended sediments, turbidity and increased sedimentation. Possible impacts are loss of habitat, loss of a food source and loss of spawning habitat. Many fishes use the river, steam and estuarine bot toms for cover, spawning mats, and food foraging areas. Increased turbidity reduces both foraging a nd avoidance capabilities while increased suspended sediments can cause physical damage and mortality. Increased sedimentation or suspended sediments can create a complete shift in population dynamics (Berry et al. 2003; Barton 1977; Reid et al. 2003; Ke rr 1995; Hedrick et al. 2006). Like invertebrates, fish use crev ices in waterbody beds for feedi ng, shelter from predators and high flow events, and reproduction. Loss of these interstitial spaces degrades fish habitat (USEPA 2006b). Sediment can also decrease the depth of or eliminate other important habitats such as stream pools and wetlands adjacent to surface waters . Riparian wetlands are particularly important for fish spawning. Fish are also affected by lo ss or decline in aquati c macrophytes, which are important sources of shelter and food for a number of fish species. Coral reef bleaching and decline severely impact fish habitat in coral reef ecosystems. The level of impact on fishes from suspended sediments and turbidity is a function of the interaction of many factors, includi ng natural sediment and turbidity levels for the area in question. Short-term increases in suspended sediment a nd turbidity levels natu rally occur and aquatic ecosystems also vary in their na tural sediment and turbidity leve ls. Studies have found that, in general, fish typically found in environments with naturally high turbidity preferred more turbid environments in the laboratory (USEPA 2009b). Othe r fish species are very sensitive to elevated sediment levels (e.g., entire salmonid fisheries ha ve been destroyed by elevated sediment levels) (USEPA 2009b). The level of impact on fishes from suspended sedi ments and turbidity also depends on other factors, including pollutant concentration; exposure duration; particle size ; ambient temperature; physical and chemical properties of the se diments; associated toxins; co -occurring stressors; and fish acclimatization, life history stage, migration, and breeding season (USEPA 2009b). In general, longer duration and higher level exposures produce greater effects. Milder , primarily behavioral effects are observed at lower magnitude and dur ation exposure levels. As exposure and duration levels increase, effects become sublethal and le thal (USEPA 2009b). Several efforts to construct models linking varying levels and durations of se diment exposure to fish responses, but responses vary widely among different species, and data ar e generally insufficient at this time to fully characterize many of them (USEPA 2009b). A construction project may produce sediment and turbidity levels significantly higher those associated with natural events, for longer periods of time, and at times when an aquatic ecosystem is unaccustomed to receiving such sediment inputs. Many fish species have seasonal migration and breeding behaviors which can be disrupted by elev ated sediment levels. Younger fish are more vulnerable to sediment impacts and are more prev alent within a population at certain times of the year (USEPA 2009b).Construction and Development NPDES Ge neral Permit Environmental Assessment

70 4.5.2 T ERRESTRIAL V EGETATION AND W ILDLIFE R ESOURCES
There are few studies available on the effects of el evated sediment and turbidity levels in aquatic ecosystems on fundamentally terrestrial wildlife th at utilize aquatic ecosy stems. Most available studies examine effects on birds. Loons appear to need clear wate r for hunting fish and may avoid turbid waters for nesting. Other studies documen ted birds modifying their fish hunting behaviors and distribution on a surface water in order to a void more turbid areas, probably because of increased foraging difficulty (USEPA 2009b). Birds, mammals, reptiles, and amphibians that consume aquatic plants, invertebrates, fish, and other aquatic organisms or otherwise ut ilize aquatic habitats for she lter and reproduction can also be affected by elevated sediment and turbidity levels in surface waters. Some species are sufficiently mobile that they can avoid impacted aquatic co mmunities and seek substitutes, if available and accessible (USEPA 2009b).

Sedimentation can also affect or eliminate riparian wetlands, important habitats for the laying of amphibian egg masses (USEPA 2009b).

4.5.3 T HREATENED & E NDANGERED S PECIES The Endangered Species Act (ESA) of 1973 (16 U.S. C. 1531 1543) establishes a national policy to protect and conserve threatened and endange red species and the ecosystems upon which they depend. The ESA prohibits Federal agencies from je opardizing threatened or endangered species or adversely modifying habitats esse ntial to their survival. The ESA is administered by the USFWS and the NMFS. Section 7 of the ESA governs in teragency cooperation and consultation. EPA has coordinated with the USFWS and the NMFS, both collectively known as the “Services.”

Coverage under the proposed CGP is available only if stormwater discharges, allowable nonstormwater discharges, and stormw ater discharge-related activities are not likely to jeopardize the continued existence of any species that are federa lly-listed as endangered or threatened (“listed”) under the ESA or result in the adverse modification or destruction of habi tat that is federallydesignated as critical under the ESA (“critical habitat”). Oper ators have an independent ESA obligation to avoid prohibited “take” of listed species under ESA Section 9. Many of the requirements and procedures in the CGP to protec t listed species will assist operators in avoiding prohibited take. Additionally, a C& D site is eligible to discharg e under the CGP only if stormwater discharges, allowable non-stormwat er discharges, or stormwater di scharge-related activities would not cause a prohibited “take” of fe derally-listed endangered or thre atened species (as defined under section 3 of the ESA and 50 CFR 17.3), unless such takes are exempted/authorized under sections 7 or 10 of the ESA.

The proposed CGP contains the both permit provi sions and also establishes a process through operator selection of eligibility criteria in an ap pendix of the permit which is focused exclusively on protection of threatened and enda ngered species and thei r critical habitat. A C&D site is only eligible for coverage under the CGP if it properl y complies with the terms and conditions of the permit; including implementing Best Management Pr actices (BMPs) discu ssed in Section 4.3 to meet the non-numeric and water quality-based effl uent limitations. This includes implementing a myriad of restrictions on erosion and sediment c ontrols, pollution prevention, and site stabilization; all which reduce impacts of the st ormwater discharge from construc tion activities on T&E species.Construction and Development NPDES Ge neral Permit Environmental Assessment

71 Operators must certify to one of the endangered sp ecies eligibility criteria listed in the appendices of the permit. If an operator cannot certify to one of the endangered species e ligibility criteria, they cannot submit an NOI to gain coverage under the CGP; instead they must apply to EPA for an individual NPDES permit. As appropriate, EP A will conduct ESA Section 7(a)(2) consultations when issuing individual permits. If there are con cerns that CGP coverage fo r a particular facility may result in adverse effects to listed species or critical habitat, EPA may hold up discharge authorization until such concerns are adequately addressed. Documentati on of both the BMP’s and supporting information for the selection of the appropria te eligibility criteria must be kept with the SWPPP and the terms and conditions of the permit are legally enforceable.

Additionally, the permit provides th e Services with the opportunity to review all NOIs and their associated certifications. Once an operator submits its NOI, its authorization to discharge is stayed during a “waiting period”. Contacts at EPA, USFW S, and NMFS within a region or state, receive an email automatically generated by EPA’s eNOI system that an NOI requesting coverage for a C&D site activity within their area of jurisdiction has been submitted and certified. This notification initiates the review period for the agen cies to confirm, reject, or put a hold on the CGP coverage pending further review. The waiting peri od provides for an opportunity for review by the Services and EPA to ensure that the operator’s cert ification of eligibility is appropriate. If the Services have concerns or questions regarding an individual discharge r’s certification of eligibility, they may request that EPA delay permit coverage fo r the identified facility. When permit coverage is delayed, the Services and EPA will work with th e affected operator to resolve any concerns. If concerns cannot be resolved, the Services can re commend that EPA deny coverage under the CGP.

Based on the above provisions, the eligibility cr iteria built into the proposed permit and their reduction of impacts to water quality from stormw ater discharges from co nstruction activities on T & E species, EPA concludes that the proposed acti on will not have a significant adverse effect on threatened and endangered species or critical hab itat present in the covera ge area of the proposed CGP.

4.5.4 T ERRESTRIAL I MPACTS FROM BMP R EQUIREMENTS OF THE P ROPOSED GCP The implementation of the requirements of the C& D Rule in the proposed GCP require permittees to follow Best Management Practices that are de scribed extensively in th e C&D Rule. The primary focus of these BMPs is the protection of the qual ity of the stormwater discharge. Consequently, there may be environmental trade-offs from some of the BMPs EPA recommends that may affect resources at C&D sites othe r than aquatic resources. EPA has considered the impacts of these recomm ended BMPs to resources other than aquatic

resources. Table 4-12 presents recommended BMPs and the t ypes of potential adve rse impacts that may result from their implementation. EPA exp ects adverse impacts from BMPs to be highly localized, limited in scope , and highly transient.

Table 4-12. EPA Menu of Stormwater BMPs for Construction Activities and the Potential for BMP-Generated Environmental Impacts

Construction Site Stormwater BMP Potent ial for Adverse Environmental ImpactsConstruction and Development NPDES Ge neral Permit Environmental Assessment

72 Construction Site Planning and Management Construction Sequencing No BMP-generated impact Construction Site BMP Inspection & Maintenance No BMP-generated impact Land Grading No BMP-generated impact Preserving Natural Vegetation No BMP-generated impact
Erosion Control Biodegradability; soil microbiology Increased nutrients/metals runoff; Dust Control Nominal impacts, depending on extent Geotextiles Nominal impacts Gradient Terraces Excavation; grading of new areas Invasive/noxious plant species Riprap Nominal impacts, depending on extent Seeding Invasive/noxious plant species Sodding Invasive/noxious plant species Soil Retention Excavation; grading of new areas Soil Roughening Excavation; grading of new areas Temporary Slope Drain Berm area impacts Excavation Wind Fences and Sand Fences Nomina l; restricted wildlife mobility if extensive
Runoff Control Check Dams Nominal impacts Excavation Excavation Excavation
Sediment Control Shallow trenching Compost Filter Berms Increased nutrients/metals runoff; Invasive/noxious plants if Compost Filter Socks Increased nutrients/metals runoff; Invasive/noxious plants if Construction Entrances Nominal impacts Fiber Rolls Shallow trenching Filter Berms Nominal impacts Sediment Basins and Rock Dams Excavation Sediment Filters and Sediment Chambers Excavation Sediment Traps Excavation Silt Fences Nominal; restricted wildlife mobility if extensive Storm Drain Inlet Protection Nominal impacts Straw or Hay Bales Nominal impacts Vegetated Buffers Nominal impacts Good Housekeeping/Ma terials Management
Concrete Washout No BMP-generated impact General Construction Site Waste Management No BMP-generated impact No BMP-generated impact No BMP-generated impact

4.5.5 C UMULATIVE I MPACTS EPA has not quantified impacts from stormwater di scharges from C&D sites for two reasons. One is that the state of the scien ce is such that although there su fficient date to support qualitativeConstruction and Development NPDES Ge neral Permit Environmental Assessment

73 statements of impact, the ability to make suffici ently reliable projections of potential quantitative impacts across the span of environments that ma y be affected is not sufficiently reliable. The numerous factors and their inter-re lationships that must be consider ed to describe cause and effect relationships are not adequately advanced to make projections with sufficient confidence to quantify and monetize costs and benef its to these biological resources. The second reason is that the proposed CGP will cove r a very wide range of aquatic resources, and the available information and analytic tools are not sufficiently reliable to attempt a bottom-up analysis that aggregates impacts of all the poten tially affected ecosystems. Rather, for the proposed CGP, similar to the C&D Rule, EPA is addressing potential impacts by assess ing costs and benefits on a national level and projecting th ese to the subset of C&D site s covered under the limited scope of the proposed CGP. EPA has confidence in its quantification and moneti zation of the impacts, costs, and benefits to physical resources:

• Modeling conducted by EPA projects an annual reduction of sediment loadings from 118,680 tons to 78,660 tons, a 34% reduc tion (40,020 tons) annually (see Table 4-3 );

• The proposed CGP is projected to reduce aver age TSS concentrations by 1.5 mg/L; average TP concentrations by 5.3 mg/L, and aver age TN concentrations by 0.02 mg/L (see Tables 4- 4 and 4-6 );

• The proposed CGP is projected to improve the water quality index in nearly 15% of reach miles potentially affected under the proposed CGP Table 4-7 ). Section 4.4 provided the estimated re ductions in loadings of TSS, Turbidity, TN, and TP that are projected under the proposed CGP. All of these potential pollutan ts have been studied in the literature and have been proven to have impact s on aquatic organisms. The removal of these pollutants will reduce unwanted sedimentation in spawning areas, prevents smothering aquatic plants and sessile invertebrates, and allow for natural light pene tration and natural predator/prey relationships. Thus, although EPA has only quant ified the impacts to physical resources, the available information on qualitative impacts to biol ogical resources supports the conclusion that the improvements resulting from the proposed CGP to physical resources will result in improvements to biological resources as well, even if not quantif iable at this time. Also as discussed in Section 4.4.5 above, in deve loping the proposed CGP, EPA has addressed the entire span of C&D industry activity and the entire span of environments most affected by stormwater discharges from C&D s ites by addressing impacts to streams, rivers, lakes and estuaries. As the Federal action of issuing a new source NP DES permit, a general permit explicitly addresses cumulative impacts by evaluating impacts, costs, a nd benefits at the Agency’s best estimate of projected industry activity that will occur under the proposed general permit. In developing the CGP EPA has addressed individual s ite-specific concerns by incorporat ing specific features into the permitting process that include a review of CGP applications that will ensure “no significant cumulative effect” will occur beca use of specific, appropriate, conditions and requirements that anticipate the consequences of multiple C&D sites as each individual applic ation is received and reviewed.

4.6 SOCIOECONOMIC RESOURCES EPA has reviewed the impacts of C&D site stormwat er discharges on socioeconomic resource costs and benefits. EPA has considered both direct indu stry compliance costs and indirect market effects from the proposed CGP due to decreased sedimentat ion and turbidity associated with the issuanceConstruction and Development NPDES Ge neral Permit Environmental Assessment

74 of the proposed CGP. EPA considered the followi ng specific market effects that could occur in response to the proposed CGP:

1. Regulatory requirements may in crease construction costs and lengthen project construction periods, which further increases total project costs. Increase d project costs may in turn adversely affect the financial performance of construction projects and the firms that undertake these projects and/or increase the prices paid by consumers of C&D industry output. Increased prices will increase sale prices or rents of completed projects. The extent to which increased construction costs manifest as higher sales prices and rents will depend on supply and demand elasticities in specific c onstruction product markets. These elasticities may vary substantially both over time, across regional markets, and within regional markets according to supply and demand conditions in specific product segments.

2. Consumers’ response to increased project prices can affect the overall bundle of characteristics (e.g., size, techni cal design and finished product specifications) that determine consumers’ value of, and price paid for, the fini shed real estate product. Faced with increased construction costs and potential price increases for a finished product, consumers (and project developers as their surrogate) may select lowe r cost specifications on other aspects of final project design. The flexibility to adjust proj ect design specifications can buffer consumers from the construction cost in crease and upward price pressure resulting from regulatory requirements, but may also result in trade-offs of valuable attributes. Such flexibility is particularly important if the potential constructio n cost and price increases are substantial and consumers faced income-based constraints on th e price (or rent) that may be paid for the finished product.

3. If producers are unable to pass al l increased costs al ong to consumers in the form of higher prices, this could lead to w eakened financial performance of, and lower employment among, C&D industry businesses. Affected businesse s may lose business value and could face financial stress, leading potential ly to reductions in business ac tivity and, in the worst case, closure of individual businesses. Given the re lative fluidity of the C&D industry sectors expected to be affected by this regulation, idle d economic resources – i.e., labor and capital – might be redeployed relatively quickly into other existing C&D indus try businesses or new industry entrants. Regional and temporal va riation in market re sponse to increased construction costs and potential price effects may lead to substantial va riation in the extent and character of impacts within the C&D industry. All of these regulatory response e ffects – increased construction co sts from regulation compliance; distribution of compliance costs among owners of undeveloped pr operty, construction businesses, and consumers; changes in the characteristics of C&D industry finished product; and potential effects on the timing and configuration of propert y development – reflect the internalization of construction-related costs to society that are currently not account ed for in the private transactions of property purchase, development, and sale/rent. These cost and price effects, and the decision responses by property owners, producers and co nsumers, are indicative of the correction of production costs and market prices to account for the costs to society that were previously unaccounted for in the various affected transactions.

4.6.1 L AND U SE Increased sedimentation in streams, rivers, and la kes from construction activ ities can affect various land uses. Irrigation water that c ontains sediment or other pollut ants from construction sites canConstruction and Development NPDES Ge neral Permit Environmental Assessment

75 harm crops and reduce agricultural productivity. Susp ended sediment can result in formation of a crust over a field and reduce wa ter absorption, inhibit soil aera tion, and prevent emergence of seedlings. Sediment transported via spray irrigati on water can also coat the leaves of plants, inhibiting plant growth and reducing crop valu e and marketability. Also, irrigation water containing dissolved salts or polluta nts can harm crops and damage so il quality (Clark et al. 1985). Pumps are often used for the movement of irrigati on water, and excess sediment levels may require the use of filters to improve water quality (USEPA 2009b). Erosion and deposition of sediment in surface waters has led to failure of pump ing equipment Wolman and Schick (1967). Surface water sedimentation also can block irrigati on water intake structures or require periodic dredging or relocation. Sedimenta tion can cause sediment build-up in irrigation water canals and other transport systems (Osterkamp et al. 1998), reducing their efficiency. Sediment build up can also accumulate in livestock water supply impoundments and reduce their capacity (USEPA 2009b).

4.6.2 W ATER R ESOURCES U SES

4.6.2.1 Water Quality Index In assessing the potential benefits of reduced construction-generated sedimentation due to the promulgation of the C&D Rule, EPA considered non-ma rket benefits such as improved aquatic life, wildlife, and habitat designated uses. These benefits will be imp lemented through their incorporation into the requirements of the proposed CGP. As described in Section 4.4.2.2 above, EPA utilized a water quality index (WQI) to provide a link between specific pollutant levels (such as dissolved oxygen) and the presence of aquatic species and the suitability for particular recreational uses. EPA estimated st ate-level household mean, lower 10 th percentile bound, and upper 90 th percentile bound willingness-to-pay for e xpected changes in WQI and aggregated benefits to the national level. EPA estimated that the total annual benefits (i n 2008$) of water quality imp rovement resulting from reduced sediment discharges from C&D sites range from a low estimate of $55 million to a high estimate of $430 million, with a mean estimate of $210 million.

4.6.2.2 Human Uses Transportation The primary effect of pollutant discharges from construction sites on navi gation and transportation is the accumulation of sediment in navigationa l channels and harbors (USEPA 2004b). Keeping these areas passable requires ex tensive dredging, which can be co stly. Issuance of the proposed CGP is expected to result in le ss frequent dredging of navigable waterways due to reduced sediment discharges from construction sites. As a result, cost savings will accrue to government and private entities responsible for maintena nce of navigational shipping channels, harbors, and other waterways. EPA used the avoided cost of navigati onal waterways dredging as a measure of benefits resulting from the issuance of the CGP. EPA’s analysis of benefits to navi gation included four primary steps:

 Identify navigable waterways that are regul arly dredged and estimate the frequency of dredging in each waterway;

 Estimate the navigable waterway maintenance co st per cubic yard of sediment dredged;Construction and Development NPDES Ge neral Permit Environmental Assessment

76  Estimate the total cost of navigable waterw ay maintenance under the baseline and postcompliance scenarios and,

 Estimate avoided costs from decreased dre dging of navigable waterways due to the reduction in sediment discharg ed from construction sites. EPA made assumptions regarding low, midpoint, a nd high estimates for the baseline dredging that will be affected by the permit in order to provide a range of benefits values. The avoided costs, based on the baseline and BAT/NSPS national project ions, are calculated as the difference in total annualized dredging costs between the current CGP and the proposed CGP, and are considered as the benefits to navigation resu lting from the proposed CGP. Table 4-13 presents annualized avoided cost estimates for navigable waterway dredging. Only the midpoint estimate for cost reductions and a 3% annual discount rate to discount and annualiz e costs is presented as this a reasonably conservative amount under each of these scenarios. Annualized savings from reduced dredging activity under the proposed CGP represents a savings of $132,250 at the midpoint estimate. The total reduction in sediment dredged from navigable waters is expected to be nearly a million cubic yards. Table 4-13 presents the avoided costs estimated under the proposed CGP from implementing the requirements of the C&D Rule.
Table 4-13. Annualized Reductions in Navigable Waterways Dredging Sediment Dredged, million cubic yd 3

Low Midpoint High

Current CGP 96.3 120.3 127.9

Proposed CGP 95.9 119.9 127.5

Reduction 0.40 0.40 0..40 Costs, 2008$

Low Midpoint High

Current CGP $ 21,827,000 $ 28,538,400 $ 30,116,200

Proposed CGP $ 21,779,772 $ 28,480,569 $ 30,054,933

Reduction $ 47,228 $ 57,831 $ 61,267
Source: total US baseline low (2,093), midpoint (2,616), and high (2,781) estimated sediment dredged and post-compliance BAT/NSPS low ($474.5 million), midpoint $620.4 million), and high ($654.7million) estimated costs, EPA 2009b

Reservoirs Reservoirs are water impoundments, often ma nmade, that serve many functions, including providing drinking water, flood control, hydropo wer supply, and recreational opportunities. The C&D Rule analyzed and quantifie d the benefits of th e reduced sedimentation from implementing the rule. As in the analysis a bove for reduction in dredging for na vigable waterways, the reduced sedimentation from the implementing the requir ements of the C&D Rule in the proposed CGP reduced the frequency of dredging needed to ma intain reservoirs. Likewise, EPA estimated the savings in the form of avoi ded costs associated with reduced reservoir dredging..Construction and Development NPDES Ge neral Permit Environmental Assessment

77 EPA assumed that all sediment entering reservoirs mu st be removed in order to maintain the current water storage capacity in the United States. The frequency of dredging is highly site-specific, depending on many factors including the average sedi ment concentration of the river or stream, the size of the reservoir and excess storage capacity, and any sediment routing practices. EPA chose a general frequency of 6 years for a midpoint estimate of a low of 2 years and a low 10 year. For this analysis, EPA assumed that the average unit cost of dredging sediment from a navigable waterway is approximately equal to the average unit co st of dredging sediment from a reservoir Table 4-14 presents annualized avoided cost estimates rese rvoir dredging implementing the C&D Rule in the proposed CGP.
Table 4-14. Annualized Reductions in Reservoir Dredging Sediment Dredged,

million cubic yd 3 Estimated Costs, 2008$
Low Midpoint High
Current CGP 444,606,867 $ 1,051,600,000 $ 1,596,800,000 $ 1,696,000,000

Proposed CGP 443,283,323 $ 1,048,596,400 $ 1,593,606,100 $ 1,692,609,600

Reduction 1,322,867 $ 3,003,600 $ 3,193,900 $ 3,390,400

Source: total US baseline (444,606,867) and post BAT/NSPS compliance estimated sediment dredged (443,283,323) and baseline low ($1,051.6 million), midpoint ($1,596.8 million), and high ($1,696.0 million) EPA 2009b Drinking Water As mentioned above in Section 4.4.2.3, the primary concern of sediment that would accumulate from unabated increase in construction site runo ff in terms of drinking water treatment is the turbidity that results from suspended sediment in the water column. As turbidity increases in drinking water influent, the variable costs of water treatment to mitigate this turbidity increase. The variable costs associated with treating drinking wa ter for turbidity are twof old: (1) Adding chemical coagulants that bond to the sediment particles an d foster precipitation from the water column and (2) disposing of the sludge re sulting from this treatment ( Table 4-15). EPA’s analysis in estimating the avoided costs for decreased sedimentation from the C&D rule consisted of modeling sediment concentrations and reductions, identifying reache s with drinking water intakes and their intake volumes, then estimating of chemical turbidity treatment cost and sl udge disposal costs.

Recreation EPA did not quantify and moneti ze certain potential benefits from the proposed CGP. This qualification was primarily directed at benefits to biological resources . However, several nonquantified benefits are identified that relate to sediment and turbidity impacts on the recreational uses of surface waters. Aesthetically, polluted water greatly reduces the aesthetic appeal of a variety of recreational activities that take place in or near surface waters, including boating, swimming, hunting, and outings to hike, jog, picnic, camp, and view wildli fe. Turbidity caused by sediment discharges may affect the safety of boating. Turbidity contributes to increased water hazards. It creates safety hazards for swimmers and divers by reducing the ability to see underwater hazards; for divers by impairing the ability to gauge water depth; and for any distressed contact water user who become submerged by making their location more difficult (USEPA 2009b). For boaters, turbidity may obscu re underwater obstacles, whichConstruction and Development NPDES Ge neral Permit Environmental Assessment

78 increases the likelihood of collisions; increased se dimentation levels may create sandbars, which increase the chances of running aground. Clark et al. (1985) estimat ed that turbidity (from all sources) may be responsible for as many as 200 boati ng fatalities and many more injuries each year. The C&D Rule analysis estimated that the value for a statistical life was approximately $7 million. At 200 boating fatalities from turbidity from all s ources, based on the C&D activity estimated to be covered under the proposed CGP, the face value of preventing these fatalities is approximately $64 million per year. As noted, however, this figure derive s from turbidity from all sources, and that due to C&D activity is only a portion of this. Still, given that this figure doe s not include any accounting for turbidity-related boating injuries, the potential monetary value of preventing boating accidents by reducing sedimentation and turbidity from C& D activities may be quite substantial (USEPA 2009b).

Table 4-15. Annualized Reductions in Drinking Water Treatment Costs Average Reduction of Tr eated Turbidity, (NTU)

Low Midpoint High

Current CGP 104.0 205.9 486.0

Proposed CGP 103.8 205.5 485.1

Reduction 0.2 0.4 0.9
Costs, 2008$
Low Midpoint High

Current CGP $ 15,764,200 $ 23,961,400 $ 29,959,800

Proposed CGP $ 15,719,194 $ 23,906,209 $ 29,901,569

Reduction $ 45,006 $ 55,191 $ 58,231

Source: total US baseline low (104 NTU), midpoint (205 .9 NTU), and high (486.0 NTU) and estimated treated turbidity and baseline low ($3,42.7 million), midpoint (520.9 million), and high ($651.3 million), EPA 2009b

Recreational fishing may also be negatively aff ected by sedimentation and turbidity. Stormwater discharges from construction sites can redu ce fish populations by inhibiting reproduction and survival by stressing predator/prey relationships. This may lead to fewer and smaller game fish. In addition, turbidity caused by sediment and other pollu tant discharges may lower catch rates of game fish for recreational anglers by reducing the dist ance over which fish can see lures. Although EPA has not quantified the poten tial decrease in fish populations du e to construction site stormwater discharges, EPA anticipates that issuing the proposed CGP will decrease sedimentation and turbidity in surface waters and result in non-quan tified benefits for a variety of surface water recreational activities

. There are also indirect benefits that accrue to improving recr eational uses. For example, a 2006 study of Maryland’s marine recrea tion businesses shows recreationa l water users can significantly contribute to economic growth in the coasta l communities in which they are based. A study undertaken under a Sea Grant Extension Program documented the value of recreational boating activity in Maryland at well over a billion dollars a year — excluding the sale price of boatsConstruction and Development NPDES Ge neral Permit Environmental Assessment

79 ( http://www.mdsg.umd.edu/programs/ex tension/communities/boating/index.php ). According to the report, approximately every 6.5 boats registered in Maryland lead to more than one full-time job somewhere in the state's economy, and each boa t contributes over $8,600 a year in economic activity. When factoring in boats that simply visit Maryland (are not registered in MD), boating’s total impact on the Maryland economy for 2006 wa s estimated at approximately $2.0 billion with over 34,500 jobs provided.

4.6.3 P OPULATION AND H OUSING
The residential subsector of the construction i ndustry comprises over one-third of the overall construction acreage subject to the proposed CGP. EPA considered potential increases in the cost of housing construction and resulting price (or rent) of housing. For the C&D Rule EPA performed a regional-level analysis (i.e., leve l of Metropolitan Statistical Areas , or MSAs) to estimate the number and fraction of potential single-family home buyers whose purchasing decisions may be affected by the potential increa se in the price of newly cons tructed, single-family housing. An MSA-level affordability analysis is preferred to regional- or national- level analyses because it captures the high variability in housing market prices and household incomes across and within states. For this analysis, EPA used MSA-level single-family new home prices and household income distributions to determine the number of prospective home-purchas ing households that are at or above the income level estimated to be n ecessary to qualify for the financing of a newly constructed single-family home. The results of the analysis at the national level were calculated by aggregating the number of potentia lly affected households across th e MSAs in each state and are summarized in Table 4-16 . Results of this analysis, unmodifie d, are applicable to the potential effects of the CGP because of the MSA-level analysis.

Table 4-16. National Results from the MSA-Leve l Affordability Lowest New Home Price AnalysisPrice and Household Affordability Effects
Weighted Average baseline Lowe st New Home Price $100,000

National Average Price Change per New SingleFamily Home Price Change / Percentage Change $130.19 / 0.14%

Number of Households Whose Purchasing Decision for a New Single -Family Lowest Priced Home Would be Affected by a Permit-Induced Increase in Housing Prices Number of Households 680 Percentage of SF home buyers qualifying for the new, in-scope lowest-priced home 0.03% Percentage of SF home buyers qualifying for the lowest-priced home 0.01%

Number of Affected Ho useholds (from above), Adjusted to Account for Estimated Number of Households Whose Empirically Observed Purchase Terms Indicate Ability to Increase Housing Payments and Remain Under 29% Housing Payment-to-Income Ratio Number of Households 324 Percentage of SF home buyers qualifying for the new, in-scope, lowest-priced home 0.02% Percentage of SF home buyers qualifying for the lowest-priced home 0.00%

Source: EPA 2009b
A number of studies, however, have identified benefits that decr easing sedimentati on and turbidity can have that positively affect housing process. For example, aesthetic degradation of land and water resources resulting from sediment and ot her pollutant discharges (e.g., increased waterConstruction and Development NPDES Ge neral Permit Environmental Assessment

80 turbidity) can reduce the market va lue of property and thus affect the financial status of property owners: hedonic price study by Bejranonda et al. ( 1999) found that “the rate of sediment inflow entering the lakes has a negative infl uence on lakeside property rent.” Sediment discharges also have an impact on st ream morphology, e.g., higher coarse sediment loads increase river bed width and resulting bank eros ion (Wheeler et al. 2003). A 1993 study of Lake Erie’s housing market found that “erosion-pr one lakeshore propert y will be discounted ” (Kriesel et al. 1993). Stabilization of stream banks leads to an increase in the value of surrounding property (Streiner and Loomis 1996). Therefor e, the final regulation is exp ected to enhance nearby property value in two ways: (1) by improving the aesthetic quality of land and water resources (e.g., reduced turbidity) and (2) by improving stream morphology and stabiliz ing river banks (USEPA, 2009b) Due to data limitations, EPA did not estimate change s in market values of properties located near water bodies expected to benefit from reduced se diment discharges from construction sites as a result of this regulation. Als o, the nonmarket component (i.e., increased satisfaction with the property) may be implicitly accounted for th e willingness-to-pay for improvements in environmental services provided by surface waters affected by construction site discharges.

4.6.4 D EMOGRAPHICS For the C&D Rule, EPA assessed those areas that ar e more or likely to have construction activity. For the most part, the greatest amount of change is in and around urban areas and benefit both the urban economically disadvantaged as well as the mo re affluent, middle class suburban residents. If this generalization is widely valid, certain groups will be more or less exposed to the costs and benefits from the proposed CGP. For example, this generalization is more likely to hold for those states covered under the proposed CGP where EPA has general permit authority, but less likely to hold in other areas covered by the proposed CGP, e .g., tribal lands and terr itories. In these latter areas, development is less likely and the expected impacts, both positive and negative, relatively less. In either case, however, there does not appear to be any disproportionate distribution of either costs or benefits among various demographic cate gories potentially affect ed by the proposed CGP. An indirect demographic affect may be the incr eased house prices as construction companies pass on the cost of permit compliance to the consumers in the form of higher housing prices. This may discourage those populations that are marginally capable of qualifying for new housing financing and could skew the buyers’ demogra phics to those with greater ec onomic means. A more in depth analysis of housing prices was presented above in Section 4.6.3.

4.6.5 C ULTURAL R ESOURCES To address potential impacts to cultural resources from the proposed action in a programmatic approach, which is needed when issuing a genera l permit, EPA is coordinating with the Advisory Council on Historic Preservation (A CHP) concerning approaches to compliance with the NHPA.

4.6.6 C UMULATIVE I MPACTS Similar to the discussions on cumulative impacts pr esented above, the proposed re-issuance of the CGP on physical resources intrin sically addresses cumulative impacts for several reasons. One reason is that the proposed CGP explicitly addr esses cumulative impacts by evaluating impacts,Construction and Development NPDES Ge neral Permit Environmental Assessment

81 costs, and benefits at the Agency’s best estimat e of projected industry ac tivity that will occur under the proposed general permit. A second reason is th at EPA has addressed the entire span of C&D industry activity, i.e., from the le vel of individual sites to aggr egated industry activity and by addressing the entire span of environments mo st affected by stormwat er discharges from C&D sites, e.g., streams, rivers, lakes and estuaries. Furthermore, EPA has addressed individual sitespecific concerns by incorporating specific features into the permitting process, e.g., the prohibition of coverage for C&D sites discharging to a wa terbody impaired for sediment, sediment-related pollution, or nutrients, or regional not ification of applications to revi ew the potential for a site to affect threatened or endangered species, historic resources, or culturally valuable resources. By incorporating such protections into the NOI pr ocess, EPA has ensured “no significant cumulative effect” will occur because the process for obtaining coverage has been developed with specific, appropriate, conditions and requirements that anticipate the cons equences of multiple C&D sites as each individual application is received and reviewed.Construction and Development NPDES Ge neral Permit Environmental Assessment

82 5. OTHER CONSIDERATIONS

5.1 CONSISTENCY WITH OTHER FEDERA L, STATE, AND LOCAL PLANS, POLICIES, AND REGULATIONS The scope of EPA’s environmental review includ es the requirements of Federal statutes and policies other than the NPDES permit program. EP A has reviewed the proposed CGP with respect to a number of these other Federal statutes and policiesEPA has identified those statutes and policies that the proposed CGP ma y potentially affect, and EPA a ddresses the consistency of the proposed CGP with these statutes and policie s in this section as described below.

5.1.1 C LEAN W ATER A CT §401 W ATER Q UALITY C ERTIFICATION BY S TATE W ATER Q UALITY A GENCIES States adopt surface water quality standards pursuant to Section 303 of the CWA. All permits for discharges to the navigable waters of the US must include effluent lim itations at least as stringent as needed to maintain established bene ficial uses and to attain the quali ty of water designated by states for their water. Under Section 401 of the CWA, a state has the authority to grant or deny “certification” for any discharge originating in th at state from a federally permitted or licensed facility or activity. If a state denies certification, the Federal permitting or licensing agency is prohibited from issuing a permit or license. The proposed CGP will comply with the requirem ents of CWA Section 401 because the proposed CGP will be submitted to the affected states and tr ibes prior to finalization. Part 10 of the proposed CGP will include any additional permit conditions requi red by states and tribes that result from the 401 certification process. The provi sions of Part 10 provide modifi cations or additions to the applicable conditions of the perm it to reflect specific additional c onditions required as part of the state or tribal CWA Section 401 certification pr ocess, or the Coastal Zone Management Act (CZMA) certification process, or as otherwise es tablished by the permitting authority. The specific additional revisions and requirement s will only apply to activities in those specific states, Indian lands, and federal facilities. States, Indian lands, and federa l facilities that are not included in Part 10 have no modifications or additions required in the final CGP.

5.1.2 E NDANGERED S PECIES A CT OF 1973 The Endangered Species Act of 1973 (ESA) establis hes a national policy to protect and conserve threatened and endangered species and the ecosystems upon which they depend. The ESA is administered by the FWS and the NMFS. Sectio n 7 of the ESA governs interagency cooperation and consultation. Based on information in Chapter 4 on the provisions, the elig ibility criteria built into the proposed permit and their reduction of impacts to water qua lity from stormwater discharges from construction activities on T & E species, EPA concludes that the proposed action will not have a significant adverse affect on th reatened and endangered species or critical habitat present in the coverage area of the proposed CGP.

5.1.3 S ECTION 106 OF THE N ATIONAL H ISTORIC P RESERVATION A CT EPA is subject to Section 106 of the National Historic Preservation Ac t of 1966 and 1996 (NHPA; 16 U.S.C 470). Under Section 106 of the National Historic Preservation Act and its implementing regulations at 36 CFR Part 800 a nd EO 11593, Federal agencies must take into account effects of their undertakings on historic prop erties listed on or eligible for listing on the National Register ofConstruction and Development NPDES Ge neral Permit Environmental Assessment

83 Historic Places. Currently, more than 80,000 propert ies have been listed in the National Register. Together these records hold information on more than 1.4 million individual resources--buildings, sites, districts, structures, and objects. Additionally, the proposed act ion covers many of the tribal lands within the United States. Tribal lands in particular have unique cultural resources that are vulnerable to development and construction activities. EPA recognizes that loca l governments and tribal councils are the best source of identifying cultural resources within their communities. To address potential impacts to cultural resources from the proposed action in a programmatic approach, which is needed when issuing a gene ral permit, EPA is coordinating with the ACHP concerning approaches to compliance with the NHPA.

5.1.4 E NVIRONMENTAL J USTICE

Executive Order 12898, Federal Actions to Address E nvironmental Justice in Minority Populations and Low-Income Populations dire cts Federal agencies to identif y and address, as appropriate, disproportionately high and adverse health or environmental effects of their programs, policies, and activities on minority populations an d low-income populations. Environm ental justice refers to the

― fair treatment and meaningful in volvement of all people regardless of race, color, national origin, or income with respect to the development, implementation, and enforcement of environmental laws, regulations, and policies.

EPA has incorporated requirements into the propos ed CGP that will decrease sedimentation and turbidity effects to surface waters . No high and adverse health or environmental effects, to either the general population, or minority and low-income populations, are ex pected from issuance of the CGP.Construction and Development NPDES Ge neral Permit Environmental Assessment

84 6. REFERENCES

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91 APPENDIX A

NATIONAL LAND COVER DATABASE DEVELO PMENT CHANGE, BY EPA REGION

Figure 1. EPA Region 1 - Percentage ur ban change 1992–2001 by ERF1_2 watershedConstruction and Development NPDES Ge neral Permit Environmental Assessment

92 Figure 2. EPA Region 2 - Percentage ur ban change 1992–2001 by ERF1_2 watershed

Figure 3. EPA Region 3 - Percentage ur ban change 1992–2001 by ERF1_2 watershedConstruction and Development NPDES Ge neral Permit Environmental Assessment

93 \

Figure 4. EPA Region 4 - Percentage ur ban change 1992–2001 by ERF1_2 watershedConstruction and Development NPDES Ge neral Permit Environmental Assessment

94 Figure 5. EPA Region 5 - Percentage ur ban change 1992–2001 by ERF1_2 watershedConstruction and Development NPDES Ge neral Permit Environmental Assessment

95 Figure 6. EPA Region 6 - Percentage ur ban change 1992–2001 by ERF1_2 watershedConstruction and Development NPDES Ge neral Permit Environmental Assessment

96 Figure 7. EPA Region 7- Percentage urban change 1992–2001 by ERF1_2 WatershedConstruction and Development NPDES Ge neral Permit Environmental Assessment

97 Figure 8. EPA Region 8 - Percentage ur ban change 1992–2001 by ERF1_2 watershedConstruction and Development NPDES Ge neral Permit Environmental Assessment

98 Figure 9. EPA Region 9 - Percentage ur ban change 1992–2001 by ERF1_2 watershedConstruction and Development NPDES Ge neral Permit Environmental Assessment

99 Figure 10. EPA Region 10 - Percentage urban change 1992–2001 by ERF1_2 watershedConstruction and Development NPDES Ge neral Permit Environmental Assessment

100