Effluent Limitations Guidelines and Standards for the Construction and Development Point Source Category

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 450

[EPA-HQ-OW-2008-0465; FRL-9086-4]

RIN 2040-AE91

Effluent Limitations Guidelines and Standards for the Construction and Development Point Source Category

AGENCY:

Environmental Protection Agency (EPA).

ACTION:

Final rule.

SUMMARY:

The Environmental Protection Agency is publishing final regulations establishing Clean Water Act (CWA) technology-based Effluent Limitations Guidelines and New Source Performance Standards for the Construction and Development (C&D) point source category. EPA expects compliance with this regulation to reduce the amount of sediment and other pollutants discharged from construction and development sites by approximately 4 billion pounds per year.

DATES:

This final rule is effective on February 1, 2010, 60 days after publication in the

Federal Register

.

ADDRESSES:

EPA has established a docket for this action under Docket ID No. EPA-HQ-OW-2008-0465. All documents in the docket are listed on the

http://www.regulations.gov

Web site. Although listed in the index, some information is not publicly available, e.g., CBI or other information whose disclosure is restricted by statute. Certain other material, such as copyrighted material, is not placed on the Internet and will be publicly available only in hard copy form. Publicly available docket materials are available either electronically through

http://www.regulations.gov

or in hard copy at the Office of Water Docket, EPA/DC, EPA West, Room 3334, 1301 Constitution Ave., NW., Washington, DC. The Public Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding legal holidays. The telephone number for the Public Reading Room is (202) 566-1744, and the telephone number for the Office of Water Docket is (202) 566-1752.

FOR FURTHER INFORMATION CONTACT:

For technical information concerning today's rule, contact Mr. Jesse W. Pritts at 202-566-1038 (

pritts.jesse@epa.gov

). For economic information contact Mr. Todd Doley at 202-566-1160 (

doley.todd@epa.gov

). For information regarding environmental benefits, contact Ms. Ashley Allen at 202-566-1012 (

allen.ashley@epa.gov

).

SUPPLEMENTARY INFORMATION:

Regulated Entities

Entities potentially regulated by this action include:

Category

Examples of regulated entities

North American industry classification system (NAICS) code

Industry

Construction activities required to obtain NPDES permit coverage and performing the following activities:

Construction of buildings, including building, developing and general contracting

236

Heavy and civil engineering construction, including land subdivision

237

EPA does not intend the preceding table to be exhaustive, but provides it as a guide for readers regarding entities likely to be regulated by this action. This table lists the types of entities that EPA is now aware could potentially be regulated by this action. Other types of entities not listed in the table could also be regulated. To determine whether your facility is regulated by this action, you should carefully examine the applicability criteria in § 450.10 of today's final rule and the definition of “storm water discharges associated with industrial activity” and “storm water discharges associated with small construction activity” in existing EPA regulations at 40 CFR 122.26(b)(14)(x) and 122.26(b)(15), respectively. If you have questions regarding the applicability of this action to a particular site, consult one of the persons listed for technical information in the preceding

FOR FURTHER INFORMATION CONTACT

section.

Supporting Documentation

Several key documents support the final regulation:

1. “Development Document for Final Effluent Guidelines and Standards for the Construction and Development Category,” EPA-821-R-09-010. (“Development Document”) This document presents EPA's methodology and technical conclusions concerning the C&D category.

2. “Economic Analysis for Final Effluent Guidelines and Standards for the Construction and Development Category,” EPA-821-R-09-011. (“Economic Analysis”) This document presents the methodology employed to assess economic impacts of the rule and the results of the analysis.

3. “Environmental Impact and Benefits Assessment for Final Effluent Guidelines and Standards for the Construction and Development Category,” EPA-821-R-09-012 (“Environmental Assessment”). This document presents the methodology to assess environmental impacts and benefits of the rule and the results of the analysis.

You can obtain electronic copies of this preamble and final rule as well as the technical and economic support documents for today's rule at EPA's Web site for the C&D rule,

http://www.epa.gov/waterscience/guide/construction

.

Overview

This preamble describes the terms, acronyms, and abbreviations used in this document; the background documents that support these final regulations; the legal authority of this final rule; a summary of the final rule; background information; and the technical and economic methodologies used by the Agency to develop this final regulation.

Table of Contents

I. Legal Authority

II. Purpose & Summary of the Final Rule

III. Background on Existing Regulatory Program

A. Clean Water Act

B. Clean Water Act Stormwater Program

1. NPDES Permits for Stormwater Discharges Associated With Construction Activity

a. General NPDES Permits

b. EPA Construction General Permit

c. State Construction General Permits

d. Individual NPDES Permits

2. Municipal Stormwater Permits and Local Government Regulation of Stormwater Discharges Associated With Construction Activity

a. NPDES Requirements

b. EPA Guidance to Municipalities

C. Other State and Local Stormwater Requirements

D. Technology-Based Effluent Limitations Guidelines and Standards

1. Best Practicable Control Technology Currently Available (BPT)

2. Best Available Technology Economically Achievable (BAT)

3. Best Conventional Pollutant Control Technology (BCT)

4. Best Available Demonstrated Control Technology (BADT) for New Source Performance Standards (NSPS)

5. Pretreatment Standards

6. EPA Authority to Promulgate Non-Numeric Effluent Limitations

7. CWA Section 304(m) Litigation

IV. Overview of the Construction Industry and Construction Activities

V. Summary of the Proposed Regulation

VI. Summary of Major Comments Received

VII. Summary of Significant Decisions and Revisions to Analyses

A. Regulatory Options

B. Cost Analysis

C. Pollutant Load Analysis

D. Economic Analysis

E. Benefits Estimation and Monetization

VIII. Characteristics of Discharges Associated With Construction Activity

IX. Description of Available Technologies

A. Introduction

B. Erosion Control Measures

C. Sediment Control Measures

D. Other Construction and Development Site Management Practices

E. Performance Data for Passive Treatment Approaches

X. Development of Effluent Limitations Guidelines and Standards and Options Selection Rationale

A. Description of the Regulatory Options Considered

1. Options Considered in the Proposal

2. Regulatory Options Considered for the Final Rule and Rationale for Consideration of Revisions to Options in the Proposed Rule

B. Non-Numeric Effluent Limitations Included in All Regulatory Options

1. Non-Numeric Effluent Limitations Contained in the Final Rule

2. Changes to the Non-Numeric Effluent Limitations Since Proposal

C. Numeric Effluent Limitations and Standards Considered

D. Selected Options for BPT, BCT, BAT and BADT for NSPS

E. Selection Rationale for BPT

F. Selection Rationale for BCT

G. Selection Rationale for BAT and BADT for NSPS

1. Selection Rationale

2. Numeric Limitations

3. Rationale for Rejecting Options 1, 2 and 3 as the Technology-Bases for BAT and BADT for NSPS

4. Definition of “New Source” for the C&D Point Source Category

XI. Methodology for Estimating Costs to the Construction and Development Industry

XII. Economic Impact and Social Cost Analysis

A. Introduction

B. Description of Economic Activity

C. Method for Estimating Economic Impacts

1. Model Project Analysis

2. Model Firm Analysis

a. Assigning Projects and Costs to Model Firms

b. Project-Level Cost Multiplier

c. Cost Pass-through

3. Housing Market Impacts

4. Impacts on the National Economy

D. Results

1. Project-Level Impacts

2. Firm-Level Impacts

3. Impacts on Governments

4. Community-Level Impacts

5. Foreign Trade Impacts

6. Impacts on New Firms

7. Social Costs

8. Small Business Impacts

XIII. Cost-Effectiveness Analysis

XIV. Non-Water Quality Environmental Impacts

A. Air Pollution

B. Solid Waste Generation

C. Energy Usage

XV. Environmental Assessment

A. Surface Water Impacts From Discharges Associated With Construction Activity

B. Quantification of Sediment Discharges Associated With Construction Activity

C. Quantification of Surface Water Quality Improvement From Reducing Discharges Associated With Construction and Development Activity

XVI. Benefit Analysis

A. Benefits Categories Estimated

B. Quantification of Benefits

XVII. Benefit-Cost Comparison

XVIII. Approach to Determining Effluent Limitations and Standards

A. Definitions

B. Percentile Basis for Limitations, not Compliance

XIX. Regulatory Implementation

A. Monitoring Requirements

B. Implementation

C. Upset and Bypass Provisions

D. Variances and Waivers

E. Safe Drinking Water Act Requirements

F. Other Clean Water Act Requirements

XX. Related Acts of Congress, Executive Orders, and Agency Initiatives

A. Executive Order 12866: Regulatory Planning and Review

B. Paperwork Reduction Act

C. Regulatory Flexibility Act

D. Unfunded Mandates Reform Act (UMRA)

E. Executive Order 13132: Federalism

F. Executive Order 13175 (Consultation and Coordination With Indian Tribal Governments)

G. Executive Order 13045: Protection of Children From Environmental Health Risks and Safety Risks

H. Executive Order 13211 (Energy Effects)

I. National Technology Transfer and Advancement Act

J. Executive Order 12898: Federal Actions To Address Environmental Justice in Minority Populations and Low-Income Populations.

K. Congressional Review Act (CRA)

L. Judicial Review

I. Legal Authority

EPA is promulgating these regulations under the authorities of sections 101, 301, 304, 306, 308, 402, 501 and 510 of the Clean Water Act (CWA), 33 U.S.C. 1251, 1311, 1314, 1316, 1318, 1341, 1342, 1361 and 1370 and pursuant to the Pollution Prevention Act of 1990, 42 U.S.C. 13101

et seq.

II. Purpose & Summary of the Final Rule

EPA is today promulgating effluent limitations guidelines (ELG) and new source performance standards (NSPS) for the C&D point source category. EPA is promulgating a series of non-numeric effluent limitations, as well as a numeric effluent limitation for the pollutant turbidity. All construction sites will be required to meet the series of non-numeric effluent limitations. Construction sites that disturb 10 or more acres of land at one time will be required to monitor discharges from the site and comply with the numeric effluent limitation. EPA is phasing in the numeric effluent limitation over four years to allow permitting authorities adequate time to develop monitoring requirements and to allow the regulated community time to prepare for compliance with the numeric effluent limitation. Construction sites that disturb 20 or more acres at one time will be required to conduct monitoring of discharges from the site and comply with the numeric effluent limitation beginning 18 months after the effective date of the final rule. Construction sites that disturb 10 or more acres at one time will be required to conduct monitoring of discharges from the site and comply with the numeric effluent limitation beginning four years after the effective date of the final rule.

The total pollutant reductions, once fully implemented, will be approximately 4 billion pounds per year. The final rule will result in an extensive range of benefits. For some of those benefits EPA was able to estimate a monetized value of approximately $369 million per year, once fully implemented. EPA could not monetize the value of some benefit categories, such as increases in property value near water bodies, reduced flood damage, and reduced cost of ditch maintenance. For other benefits categories, such as swimming and fishing, EPA was able to partially monetize the benefits. The costs of the final rule in 2010, which is the first year in which the rule must be incorporated into National Pollutant Discharge Elimination System (NPDES) permits, are estimated to be $8 million. Costs in 2011 are estimated to be $63 million. Since this regulation will be implemented over time due to the schedule by which EPA and states will be issuing new or reissued permits, the annual cost of the rule will be $810 million after all states have incorporated the requirements of the final rule into their NPDES permits in 2014. EPA

expects that after the rule is fully incorporated into EPA and state NPDES permits after the industry has returned to normal levels of construction activity, the annual cost of the rule will be $953 million.

The goal of the Clean Water Act is to restore and maintain the chemical, physical and biological integrity of the Nation's waters. CWA section 101, 33 U.S.C. 1251. Despite substantial improvements in the nation's water quality since the inception of the Clean Water Act, many of the nation's surface waters continue to be impaired. EPA's Assessment TMDL Tracking and Implementation System (ATTAINS) provides information on water quality conditions reported by the states to EPA under Sections 305(b) and 303(d) of the Clean Water Act. According to ATTAINS (as of September 17, 2009), 49 percent of assessed river and stream miles, 66 percent of assessed lake area, and 63 percent of assessed bay and estuary area is impaired by a wide range of sources. Improper control of stormwater discharges associated with construction activity is a contributor of sediment, turbidity, nutrients and other pollutants to surface waters in the United States. Sediment (both suspended and deposited) and turbidity are common construction site pollutants and are significant causes of surface water quality impairment. According to ATTAINS (as of September 17, 2009), turbidity contributes to impairment of 26,278 miles of assessed rivers and streams, 1,008,276 acres of assessed lakes, and reservoirs, and 240 square miles of assessed bays and estuaries. These figures probably underestimate the extent of turbidity impairment since many waters have not yet been assessed. EPA's

Wadeable Streams Assessment

(2006) is a statistical survey of the smaller perennial streams and rivers that comprise 90 percent of all perennial stream miles in the coterminous United States. According to the survey, excess streambed sedimentation is one of the most widespread stressors, with 25 percent of streams in “poor” streambed sediment condition.

The sediment, turbidity, and other pollutants entrained in stormwater discharges associated with construction activity contribute to aquatic ecosystem degradation, increased drinking water treatment costs, and impairment of the recreational use and aesthetic value of impacted waters. Sediment can also accumulate in rivers, lakes, and reservoirs, leading to the need for dredging or other mitigation in order to prevent reduced water storage or navigation capacity.

Construction activity typically involves site selection and planning, and land-disturbing tasks such as clearing, excavating and grading. Disturbed soil, if not managed properly, can be easily washed off-site during storm events. Stormwater discharges during construction activities containing sediment and turbidity can cause an array of physical, chemical and biological impacts on receiving waters. In addition to sediment and turbidity, a number of other pollutants (e.g., metals, organic compounds and nutrients) are preferentially absorbed or adsorbed onto mineral or organic particles found in fine sediment. These pollutants can cause an array of chemical and biological water quality impairments. The interconnected processes of erosion (i.e., detachment of soil particles by water), sediment transport, and delivery to receiving waters are the primary pathways for the addition of pollutants from construction and development sites (hereinafter C&D sites; construction sites; or sites) into aquatic systems.

A primary concern at most C&D sites is the erosion and transport process related to fine sediment because rain splash, rills (small channels typically less than one foot deep) and sheetwash (thin sheets of water flowing across a surface) encourage the detachment and transport of sediment to water bodies. Although streams and rivers naturally carry sediment loads, discharges associated with construction activity can elevate these loads to levels above those in undisturbed watersheds. In addition, discharges from C&D sites can increase the proportion of silt, clay and colloidal particles in receiving streams because these fine-grained particles may not be effectively managed by conventional erosion and sediment controls utilized at C&D sites that rely on simple settling.

Existing national stormwater regulations at 40 CFR 122.26 require dischargers engaged in construction activity to obtain NPDES permit coverage and to implement control measures to manage discharges associated with construction activity. This category is the largest category of dischargers in the NPDES program. However, there are currently no national performance standards or monitoring requirements for this category of dischargers. Today's regulation establishes a technology-based “floor” or minimum requirements on a national basis. This rule constitutes the nationally applicable, technology-based ELG and NSPS applicable to all dischargers currently required to obtain a NPDES permit pursuant to 40 CFR 122.26(b)(14)(x) and 122.26(b)(15). This rule focuses on discharges composed of stormwater but the ELGs and NSPSs also apply to other discharges of pollutants from C&D sites, such as discharges from dewatering activities. CWA section 301(a). The ELGs and NSPSs would require stormwater discharges from most C&D sites to meet effluent limitations designed to reduce the amount of sediment, turbidity, Total Suspended Solids (TSS) and other pollutants in stormwater discharges from the site.

EPA acknowledges that many state and local governments have existing programs for controlling stormwater and wastewater discharges from construction sites. Today's ELGs and NSPS are intended to work in concert with these existing state and local programs and in no way does EPA intend for this regulation to interfere with existing state and local requirements that are more stringent than this rule or with the ability of state and local governments to promulgate new and more stringent requirements. Today's regulation requires all permittees to implement a range of erosion and sediment controls and pollution prevention measures at regulated construction sites. Today's regulation also establishes a numeric effluent limitation for turbidity in discharges from C&D sites that disturb ten or more acres of land at one time. Permittees would be required to sample stormwater discharges from the site and report the levels of turbidity present in the discharges to the permitting authority. These effluent limitations would, for many sites, require an additional layer of management practices and/or treatment above what most state and local programs are currently requiring. Permitting authorities are required to incorporate these turbidity limitations into their permits and permittees are required to implement control measures to meet a numeric turbidity limitation in discharges of stormwater from their C&D sites. EPA is not dictating that specific technologies be used to meet the numeric limitation, but is specifying the maximum daily turbidity level that can be present in discharges from C&D sites. EPA's limitations are based on its assessment of what specific technologies can reliably achieve. Permittees have the flexibility to select management practices or technologies that are best suited to site-specific conditions present on each individual C&D site if they are able to consistently meet the limitations and if they are consistent with requirements established by the permitting authority.

Permittees also have the ability to phase their construction activities to limit applicability of the monitoring requirements and turbidity limitation.

EPA expects that today's regulation will result in reductions in pollutant discharges and substantial improvements in receiving water quality nationally in areas where construction activities are occurring and downstream of areas where construction activities are occurring. In addition, the monitoring requirements contained in today's rule will significantly increase transparency and accountability for the largest category of NPDES dischargers and provide permittees, permitting authorities and the public with an important mechanism for gauging compliance with the regulations and standards.

III. Background on Existing Regulatory Program

A. Clean Water Act

Congress passed the Federal Water Pollution Control Act of 1972 (Pub. L. 92-500, October 18, 1972) (hereinafter the Clean Water Act or CWA), 33 U.S.C. 1251

et seq.,

with the stated objectives to “restore and maintain the chemical, physical, and biological integrity of the Nation's waters.” Section 101(a), 33 U.S.C. 1251(a). To achieve this goal, the CWA provides that “the discharge of any pollutant by any person shall be unlawful” except in compliance with other provisions of the statute. CWA section 301(a). 33 U.S.C. 1311. The CWA defines “discharge of a pollutant” broadly to include “any addition of any pollutant to navigable waters from any point source.” CWA section 502(12). 33 U.S.C. 1362(12). EPA is authorized under CWA section 402(a) to issue a NPDES permit for the discharge of any pollutant from a point source. These NPDES permits are issued by EPA regional offices or NPDES authorized state or tribal agencies. Since 1972, EPA and the states have issued NPDES permits to thousands of dischargers, both industrial (e.g., manufacturing, energy and mining facilities) and municipal (e.g., sewage treatment plants). As required under Title III of the CWA, EPA has promulgated ELGs and standards for many industrial point source categories, and these requirements are incorporated into the permits. The Water Quality Act (WQA) of 1987 (Pub. L. 100-4, February 4, 1987) amended the CWA, adding CWA section 402(p), requiring implementation of a comprehensive program for addressing stormwater discharges. 33 U.S.C. 1342(p).

B. Clean Water Act Stormwater Program

Prior to the WQA of 1987, there were numerous questions regarding the appropriate means of regulating stormwater discharges within the NPDES program due to the serious water quality impacts of stormwater, the variable nature of stormwater, the large number of stormwater point sources and permitting agency resources. EPA undertook numerous regulatory actions, which resulted in extensive litigation, in an attempt to address these unique discharges. Congress, with the addition of section 402(p), established a structured and phased approach to address stormwater discharges and fundamentally altered the way stormwater is addressed under the CWA as compared with process wastewater or other discharges of pollutants. Section 402(p)(1) created a temporary moratorium on NPDES permits for point source stormwater discharges, except for those listed in section 402(p)(2), including dischargers already required to have a permit and discharges associated with industrial activity. In 1990, pursuant to section 402(p)(4), EPA promulgated the Phase I stormwater regulations for those stormwater discharges listed in 402(p)(2). 55 FR 47990 (November 16, 1990). The Phase I regulations required NPDES permit coverage for discharges associated with industrial activity and from “large” and “medium” municipal separate storm sewer systems (MS4s). CWA section 402(p)(2). As part of that rulemaking, the Agency interpreted stormwater “discharges associated with industrial activity” to include stormwater discharges associated with “construction activity” as defined at 40 CFR 122.26(b)(14)(x). As described in the Phase I regulations, dischargers must apply for and obtain authorization to discharge (or “permit coverage”), and a permit is required for discharges associated with construction activity, including clearing, grading, and excavation, if the construction activity:

• Will result in the disturbance of five acres or greater; or

• Will result in the disturbance of less than five acres of total land area that is a part of a larger common plan of development or sale if the larger common plan will ultimately disturb five acres or greater.

See 40 CFR 122.26(b)(14)(x) and (c)(1). These discharges associated with “large” construction activity are one of the categories of stormwater dischargers EPA defined as associated with industrial activity. See 40 CFR 122.26(b)(14).

Section 402(p)(6) established a process for EPA to evaluate potential sources of stormwater discharges not included in the Phase I regulations and designation of those discharges for regulation in order to protect water quality. Section 402(p)(6) instructs EPA to “issue regulations * * * which designate stormwater discharges, other than those discharges described in [section 402(p)(2)], to be regulated to protect water quality and shall establish a comprehensive program to regulate such designated sources.” In 1999, pursuant to the broad discretion granted to the Agency under section 402(p)(6), EPA promulgated the Phase II stormwater regulations which designated discharges associated with “small” construction activity and “small” MS4s. 64 FR 68722 (December 8, 1999). An NPDES permit is required for discharges associated with small construction activity, including clearing, grading, and excavation, if the construction activity:

• Will result in land disturbance of equal to or greater than one acre and less than five acres; or

• Will result in disturbance of less than one acre of total land area that is part of a larger common plan of development or sale if the larger common plan will ultimately disturb equal to or greater than one and less than five acres.

See 40 CFR 122.26(b)(15).

EPA continues to have the authority to use section 402(p)(6) to designate additional stormwater discharges for regulation under the CWA in order to protect water quality. See 40 CFR 122.26(a)(9)(i)(C)-(D); see also

Envt Defense Ctr.

v.

EPA,

344 F.3d 832, 873-76 (9th Cir. 2003).

In addition, as stated above, the Phase I and Phase II regulations require NPDES permits for “large,” “medium,” and “small” MS4s. Operators of these MS4s, typically local governments, must develop and implement a stormwater management program, including a requirement to address stormwater discharges associated with construction activity and discharges after construction activity. More details on the requirements of MS4 programs are described in section III.B.2.

1. NPDES Permits for Stormwater Discharges Associated With Construction Activity

The NPDES regulations provide two options for obtaining authorization to discharge or “permit coverage”: General permits and individual permits. A brief description of these types of permits as they apply to C&D sites follows.

a. General NPDES Permits

The vast majority of discharges associated with construction activity are covered under NPDES general permits. EPA, states and tribes use general permits to cover a group of similar dischargers under one permit. See 40 CFR 122.28. General permits simplify the process for dischargers to obtain authorization to discharge, provide permit requirements for any discharger that files a notice of intent to be covered, and reduce the administrative workload for NPDES permitting authorities. General permits, including a fact sheet describing the rationale for permit conditions, are issued by NPDES permitting authorities after an opportunity for public review of the proposed general permit. Typically, to obtain authorization to discharge under a construction general permit, a discharger (the owner or operator of the C&D sites; typically, a developer, builder, or contractor) submits to the permitting authority a Notice of Intent (NOI) to be covered under the general permit. A NOI is not a permit or a permit application, see

Texas Independent Producers and Royalty Owners Ass'n

v.

EPA,

410 F.3d 964, 977-78 (7th Cir. 2005), but by submitting the NOI, the discharger acknowledges that it is eligible for coverage under the general permit and agrees to the conditions in the published general permit. Discharges associated with the construction activity are authorized consistent with the terms and conditions established in the general permit.

EPA regulations allow NPDES permitting authorities to regulate discharges from small C&D sites under a general permit without the discharger submitting an NOI if the permitting authority determines an NOI is inappropriate and the general permit includes language acknowledging that an NOI is unnecessary (40 CFR 122.28(b)(2)(v)). To implement such a requirement, the permitting authority must specify in the public notice of the general permit any reasons why an NOI is not required. In these instances, any stormwater discharges associated with small construction activity are automatically covered under an applicable general permit and the discharger is required to comply with the terms, conditions and effluent limitations of such permit.

Similarly, EPA, states and tribes have the authority to notify a C&D site operator that it is covered by a general permit, even if that operator has not submitted an NOI (40 CFR 122.28(b)(2)(vi)). In these instances, the operator is given the opportunity to request coverage under an individual permit. Individual permits are discussed in section III.B.1.d.

b. EPA Construction General Permit

Since 1992, EPA has issued a series of “national” Construction General Permits (CGP) that cover areas where EPA is the NPDES permitting authority. At present, EPA is the permitting authority in four states (Idaho, Massachusetts, New Hampshire, and New Mexico), the District of Columbia, Puerto Rico, all other U.S. territories with the exception of the Virgin Islands, federal facilities in four states (Colorado, Delaware, Vermont, and Washington), most Indian lands and a couple of other specifically designated activities in specific states (e.g., oil and gas activities in Texas and Oklahoma). EPA's current CGP became effective on June 30, 2008 (see 74 FR 40338). EPA has proposed to modify the expiration date of the current 2008 CGP for one year, to June 30, 2011, in order to allow EPA adequate time to incorporate the ELGs and NSPS in this final rule and provide any necessary guidance to the regulated industry (see 74 FR 53494). At that time, EPA will issue a new CGP that includes the requirements of this final rule.

The key components of EPA's current CGP are non-numeric effluent limitations and “best management practices” (BMP) that require the permittee to minimize discharges of pollutants in stormwater discharges using control measures that reflect best engineering practices based on EPA's best professional judgment. Dischargers must minimize their discharge of pollutants in stormwater using appropriate erosion and sediment controls and control measures for other pollutants such as litter, construction debris, and construction chemicals that could be exposed to stormwater and other wastewater. The 2008 EPA CGP requires dischargers to develop and implement a stormwater pollution prevention plan (SWPPP) to document the steps they will take to comply with the terms, conditions and effluent limitations of the permit. EPA's guidance manual, “Developing Your Stormwater Pollution Prevention Plan: A Guide for Construction Sites,” (EPA 833/R-060-04, May 2007; available on EPA's Web site at

http://www.epa.gov/npdes/stormwater

) describes the SWPPP process in detail. As detailed in EPA's CGP, the SWPPP must include a description of the C&D site with maps showing drainage patterns, discharge points, and locations of discharge controls; a description of the control measures used; and inspection procedures. A copy of the SWPPP must be kept on the construction site from the date of project initiation to the date of final stabilization. The CGP does not require permittees to submit a SWPPP to the permitting authority; however, a copy must be readily available to authorized inspectors during normal business hours. Other requirements in the CGP include conducting regular inspections and reporting releases of reportable quantities of hazardous substances.

c. State Construction General Permits

Whether EPA, a state or a tribe issues the general permit, the CWA and EPA regulations require that NPDES permits must include technology-based effluent limitations. 40 CFR 122.44. In addition, where technology-based effluent limitations are insufficient for the discharge to meet applicable water quality standards, the permit must contain water quality-based effluent limitations as necessary to meet those standards. See sections 301, 304, 303, 306, and 402 of the CWA.

PUD No. 1 of Jefferson County

v.

Washington Department of Ecology,

511 U.S. 700, 704-705 (1994).

For the most part, state-issued general permits for stormwater discharges associated with construction activity have followed EPA's CGP format and content, starting with EPA's first CGP issued in 1992 (57 FR 41176; September 9, 1992). Over time, some states have changed components of their permits to better address the specific conditions encountered at construction sites within their jurisdiction (e.g., soil types, topographic or climatic characteristics, or other relevant factors). For example, the States of Washington, Oregon, Georgia and Vermont's CGPs include discharge monitoring requirements for C&D sites applicable to all or a subset of construction sites. In addition, the State of California's current CGP contains monitoring requirements as well as numeric effluent limitations for a subset of construction sites within the state.

d. Individual NPDES Permits

A permitting authority may require any C&D site to apply for an individual permit rather than using the general permit. Likewise, any discharger may request to be covered under an individual permit rather than seek coverage under an otherwise applicable general permit (40 CFR 122.28(b)(3)). Unlike a general permit, an individual permit is intended to be issued to one permittee, or a few co-permittees. Individual permits for stormwater discharges from construction sites are

rarely used, but when done so, are most often used for very large projects or projects located in sensitive watersheds. EPA estimates that fewer than one half of one percent (< 0.5%) of all construction sites are covered under individual permits.

2. Municipal Stormwater Permits and Local Government Regulation of Stormwater Discharges Associated With Construction Activity

Many local governments, as MS4 permittees, have a role to play in the regulation of construction activities. This section provides an overview of MS4 responsibilities associated with controlling stormwater discharges associated with construction activity.

a. NPDES Requirements

A municipal separate storm sewer system (MS4) is generally a conveyance or system of conveyances owned or operated by a public body that discharges to waters of the United States and is designed or used for collecting or conveying stormwater. These systems are not combined sewers and not part of a Publicly Owned Treatment Works (POTW). See 40 CFR 122.26(b)(8) for an exact definition. An MS4 is all large, medium, and small municipal storm sewers or those designated as such under EPA regulations. See 40 CFR 122.26(b)(18). The NPDES stormwater regulations require many MS4s to apply for permits. In general, the 1990 Phase I rule requires MS4s serving populations of 100,000 or more to obtain coverage under an MS4 individual permit. See 40 CFR 122.26(a)(3). The 1999 Phase II rule requires most small MS4s located in urbanized areas also to obtain coverage. See 40 CFR 122.33. Regardless of the type of permit, MS4s are required to develop stormwater management programs that detail the procedures they will use to control discharges of pollutants in stormwater from the MS4.

The Phase II regulations also provide permitting authorities or the EPA Regional Administrator with the authority to designate any additional stormwater discharges for permit coverage where he or she determines that stormwater controls are needed for the discharge based on wasteload allocations that are part of total maximum daily loads (TMDL) that address pollutants of concern or that the discharge, or category of discharges within a geographic area, contributes to a violation of a water quality standard or is a significant contributor of pollutants to waters of the United States. 40 CFR 122.26(9)(a)(i)(C) and (D).

Both the Phase I and II rules require regulated municipalities to develop stormwater management programs which include, among other elements, the control of discharges from construction sites. The Phase I regulations require medium and large MS4s to implement and maintain a program to reduce pollutants in stormwater discharges associated with construction activities, including procedures for site planning, requirements for structural and non-structural BMPs, procedures for identifying priorities for inspecting sites and enforcing control measures, and development and dissemination of appropriate educational and training materials. In general, the Phase II regulations require small MS4s to develop, implement, and enforce a program to control pollutants in stormwater discharges associated with construction activities which includes developing an ordinance to require implementation of erosion and sediment control practices, to control waste and to have procedures for site plan review and site inspections. Thus, as described above, both the Phase I and Phase II regulations specifically anticipate a local program for controlling stormwater discharges associated with construction activity. See 40 CFR 122.26(d)(2)(iv)(D) for Phase I MS4s and 40 CFR 122.34(b)(4) for Phase II MS4s. EPA has provided guidance materials to the NPDES permitting authorities and MS4s that recommend components and activities for a well-operated local stormwater management program.

EPA promulgated two provisions intended to minimize potential duplication of requirements or inconsistencies between requirements. First, 40 CFR 122.35 provides that a small MS4 is allowed to rely on another entity's program to satisfy its NPDES permit obligations, including construction site control, provided the other entity implements a program that is at least as stringent as the corresponding NPDES permit requirements and the other entity agrees to implement the control measures on the small MS4's behalf. Thus, for example, where a county implements a construction site stormwater control program already, and that program is at least as stringent as the controls required by a small MS4's NPDES permit, the MS4 may reference that program in the Notice of Intent to be covered by a general permit, or in its permit application, rather than developing and implementing a new program to require control of construction site stormwater within its jurisdiction.

Similarly, EPA or the state permitting authority may substitute certain aspects of the requirements of the EPA or state permit by incorporating by reference the requirements of a “qualifying local program” in the EPA or state CGP. A “qualifying local program” is an existing sediment and erosion control program that meets the minimum requirements as established in 40 CFR 122.44(s). By incorporating a qualifying local, state or tribal program into the EPA or state CGP, construction sites covered by the qualifying program in that jurisdiction would simply follow the incorporated local requirements in order to meet the corresponding requirements of the EPA or state CGP.

b. EPA Guidance to Municipalities

EPA developed several guidance documents for municipalities to implement the NPDES Phase II rule.

• National Menu of BMPs (

http://cfpub.epa.gov/npdes/stormwater/menuofbmps/index.cfm

). This document provides guidance to regulated MS4s as to the types of practices they could use to develop and implement their stormwater management programs. The menu includes descriptions of practices that local programs can implement to reduce impacts of stormwater discharges from construction activities.

• Measurable Goals Guidance for Phase II MS4s (

http://cfpub.epa.gov/npdes/stormwater/measurablegoals/index.cfm

). This document assists small MS4s in defining performance targets and includes examples of goals for practices to control stormwater discharges from construction activities.

• Stormwater Phase II Compliance Assistance Guide (EPA 833-R-00-002, March 2000). The guide provides an overview of compliance responsibilities for MS4s, small construction sites, and certain other industrial stormwater discharges affected by the Phase II rule.

• Fact Sheets on various stormwater control technologies, including hydrodynamic separators (EPA 832-F-99-017), infiltrative practices (EPA 832-F-99-018 and EPA 832-F-99-019), modular treatment systems (EPA 832-F-99-044), porous pavement (EPA 832-F-99-023), sand filters (EPA 832-F-99-007), turf reinforcement mats (EPA 832-F-99-002), vegetative covers (EPA 832-F-99-027), swales (EPA 832-F-99-006) and wet detention ponds (EPA 832-F-99-048). (Available at

http://www.epa.gov/npdes/stormwater/;

click on “Publications.”)

C. Other State and Local Stormwater Requirements

States and municipalities may have other requirements for flood control, erosion and sediment control, and in

many cases, stormwater management. Many of these provisions were enacted before the promulgation of the EPA Phase I stormwater rule although many have been updated since. EPA found that all states have laws for erosion and sediment control measures, with these laws implemented by state, county, or local governments. A summary of existing state requirements is provided in the Development Document.

D. Technology-Based Effluent Limitations Guidelines and Standards

Effluent limitations guidelines and new source performance standards are technology-based effluent limitations required by CWA sections 301 and 306 for categories of point source discharges. These effluent limitations, which can be either numeric or non-numeric, along with water quality-based effluent limitations, if necessary, are incorporated into NPDES permits. ELGs and NSPSs are based on the degree of control that can be achieved using various levels of pollutant control technology as defined in Title III of the CWA and outlined below.

1. Best Practicable Control Technology Currently Available (BPT)

In establishing effluent limitations guidelines for a point source category, the CWA requires EPA to specify BPT effluent limitations for conventional, toxic, and nonconventional pollutants. In doing so, EPA is required to determine what level of control is technologically available and economically practicable. CWA section 301(b)(1)(A). In specifying BPT, the CWA requires EPA to look at a number of factors. EPA considers the total cost of application of technology in relation to the effluent reduction benefits to be achieved from such application. The Agency also considers the age of the equipment and facilities, the process employed and any required process changes, engineering aspects of the application of the control technologies, non-water quality environmental impacts (including energy requirements), and such other factors as the Administrator deems appropriate. CWA section 304(b)(1)(B). Traditionally, EPA establishes BPT effluent limitations based on the average of the best performance of facilities within the category of various ages, sizes, processes or other common characteristics. Where existing performance is uniformly inadequate, EPA may require higher levels of control than currently in place in a category if the Agency determines that the technology can be practicably applied. See e.g.,

American Frozen Foods Inst.

v.

Train,

539 F.2d 107, 117 (D.C. Cir. 1976).

EPA assesses the cost-reasonableness of BPT limitations by considering the cost of treatment technologies in relation to the effluent reduction benefits achieved. This inquiry does not limit EPA's broad discretion to adopt BPT limitations that are achievable with available technology. This “limited cost-benefit analysis” is intended to “limit the application of technology only where the additional degree of effluent reduction is wholly out of proportion to the costs of achieving such marginal level of reduction.” See

EPA

v.

National Crushed Stone Ass'n,

449 U.S. 64 71 (1980). Moreover, the inquiry does not require the Agency to quantify benefits in monetary terms. See, e.g.,

American Iron and Steel Institute

v.

EPA,

526 F.2d 1027, 1051 (3rd Cir. 1975).

In balancing costs against the effluent reduction, EPA considers the volume and nature of the expected discharges after application of BPT and the cost and economic impacts of the required level of pollution control. In past effluent limitation guidelines, BPT cost-reasonableness comparisons ranged from $0.26 to $41.44 per pound removed (in 2008 dollars). This range is not inclusive of all categories regulated by BPT, but nonetheless represents a very broad range of cost-reasonableness values. About half of the cost-reasonableness values represented by this range are less than $2.99 per pound (in 2008 dollars).

2. Best Available Technology Economically Achievable (BAT)

BAT effluent guidelines are applicable to toxic (priority) and nonconventional pollutants. EPA has identified 65 pollutants and classes of pollutants as toxic pollutants, of which 126 specific substances have been designated priority toxic pollutants. 40 CFR 401.15 and 40 CFR part 423, Appendix A. In general, BAT represents the best available performance of facilities through application of the best control measures and practices achievable including treatment techniques, process and procedure innovations, operating methods, and other alternatives within the point source category. CWA section 304(b)(2)(A). The factors EPA considers in assessing BAT include the cost of achieving BAT effluent reductions, the age of equipment and facilities involved, the processes employed, the engineering aspects of the control technology, potential process changes, non-water quality environmental impacts (including energy requirements), and such factors as the Administrator deems appropriate. CWA section 304(b)(2)(B). The Agency retains considerable discretion in assigning the weight to be accorded to these factors.

Weyerhaeuser Company

v.

Costle,

590 F.2d 1011, (D.C. Cir. 1978). An additional factor, derived from the statutory phrase best available technology economically achievable, is “economic achievability.” CWA section 301(b)(2)(A). EPA may determine the economic achievability of an option on the basis of the overall effect of the rule on the industry's financial health. See

E.I. du Pont de Nemours & Co.

v.

Train,

430 U.S. 112, 129 (1977);

American Frozen Food Inst.

v.

Train,

539 F.2d 107, 131 (D.C. Cir. 1976). The Agency may base BAT limitations upon effluent reductions attainable through changes in a facility's processes and operations.

See Texas Oil &

Gas Ass'n

v.

EPA,

161 F.3d 923, 928 (5th Cir. 1998) (citing “process changes” as one factor EPA considers in determining BAT); see also,

American Meat Institute

v.

EPA,

526 F.2d 442, 464 (7th Cir. 1975). As with BPT, where existing performance is uniformly inadequate, EPA may base BAT upon technology transferred from a different subcategory or from another category. See

CPC International Inc.

v.

Train,

515 F.2d 1032, 1048 (8th Cir. 1975) (established criteria EPA must consider in determining whether technology from one industry can be applied to another); see also,

Tanners' Council of America, Inc.

v.

Train,

540 F.2d 1188 (4th Cir. 1976). In addition, the Agency may base BAT upon manufacturing process changes or internal controls, even when these technologies are not common industry practice. See

American Frozen Foods Inst.

v.

Train,

539 F.2d 107, 132 (D.C. Cir. 1976);

Reynolds Metals Co.

v.

EPA,

760 F.2d 549, 562 (4th Cir. 1985);

California & Hawaiian Sugar Co.

v.

EPA,

553 F.2d 280 (2d Cir. 1977).

3. Best Conventional Pollutant Control Technology (BCT)

The 1977 amendments to the CWA required EPA to identify effluent reduction levels for conventional pollutants associated with BCT technology for discharges from existing point sources. BCT is not an additional limitation, but replaces Best Available Technology (BAT) for control of conventional pollutants. In addition to other factors specified in CWA section 304(b)(4)(B), the Act requires that EPA establish BCT limitations after consideration of a two-part “cost-reasonableness” test. EPA explained its methodology for the development of BCT limitations in July 1986. 51 FR 24974 (July 9, 1986).

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

5

), total suspended solids (TSS), fecal coliform, pH, and any additional pollutants defined by the Administrator as conventional. 40 CFR 401.16. The Administrator designated oil and grease as an additional conventional pollutant. 44 FR 44501 (July 30, 1979).

4. Best Available Demonstrated Control Technology (BADT) for New Source Performance Standards (NSPS)

NSPS apply to all pollutants and reflect effluent reductions that are achievable based on the BADT. New sources, as defined in CWA section 306, have the opportunity to install the best and most efficient production processes and wastewater treatment technologies. As a result, NSPS should represent the greatest degree of effluent reduction attainable through the application of the best available demonstrated control technology. In establishing NSPS, CWA section 306 directs EPA to take into consideration similar factors that EPA considers when establishing BAT, namely the cost of achieving the effluent reduction and any non-water quality, environmental impacts and energy requirements.

5. Pretreatment Standards

The CWA also defines standards for indirect discharges, i.e. discharges into publicly owned treatment works (POTWs). These standards are known as Pretreatment Standards for Existing Sources (PSES) and Pretreatment Standards for New Sources (PSNS), and are promulgated under CWA section 307(b). EPA has no data concerning the discharge of pollutants from construction sites to POTWs and POTW treatment plants. Therefore, EPA did not propose PSES or PSNS for the C&D category and is not promulgating PSES or PSNS for the C&D category. EPA determined that the majority of construction sites discharge either directly to waters of the U.S. or through MS4s. In some urban areas, construction sites may discharge to combined sewer systems (i.e., sewers carrying both stormwater and domestic sewage through a single pipe) which lead to POTW treatment plants. Sediment and turbidity, which are the primary pollutants associated with construction site discharges, are susceptible to treatment in POTWs, using technologies commonly employed such as primary clarification. EPA has no evidence that construction site discharges to POTWs would cause interference, pollutant pass-through or sludge contamination.

6. EPA Authority to Promulgate Non-Numeric Effluent Limitations

The regulations promulgated today include non-numeric effluent limitations that will control the discharge of pollutants from C&D sites. It is well established that EPA has the authority to promulgate non-numeric effluent limitations in addition to, or in lieu of, numeric limitations. The CWA does not mandate the use of numeric limitations and EPA's position finds support in the language of the CWA. The definition of “effluent limitation” means “

any

restriction * * * on quantities, rates, and concentrations of chemical, physical, biological, and other constituents * * *” CWA section 502(11) (emphasis added). EPA regulations reflect the Agency's long standing interpretation that the CWA allows for non-numeric effluent limitations. EPA regulations explicitly allow for non-numeric effluent limitations for the control of toxic pollutants and hazardous substances from ancillary industrial activities; for the control of storm water discharges; when numeric effluent limitations are infeasible; or when the practices are reasonably necessary to achieve effluent limitations and standards or to carry out the purposes and intent of the CWA. See 40 CFR 122.44(k).

Federal courts have recognized EPA's authority under the CWA to use non-numeric effluent limitations. In

Citizens Coal Council

v.

U.S. EPA,

447 F3d 879, 895-96 (6th Cir. 2006), the Sixth Circuit, in upholding EPA's use of non-numeric effluent limitations, agreed with EPA that it derives authority under the CWA to incorporate non-numeric effluent limitations for conventional and non-conventional pollutants. See also,

Waterkeeper Alliance, Inc.

v.

U.S. EPA,

399 F.3d 486, 496-97, 502 (2d Cir. 2005) (EPA use of non-numerical effluent limitations in the form of best management practices are effluent limitations under the CWA);

Natural Res. Def. Council, Inc.

v.

EPA,

673 F.2d 400, 403 (D.C. Cir. 1982) (“section 502(11) [of the CWA] defines `effluent limitation' as `any restriction' on the amounts of pollutants discharged, not just a numerical restriction.”).

7. CWA Section 304(m) Litigation

EPA identified the C&D point source category in its CWA section 304(m) plan in 2000 as an industrial point source category for which EPA intended to conduct rulemaking. 65 FR at 53008 and 53011 (August 31, 2000). On June 24, 2002, EPA published a proposed rule that contained several options for the control of stormwater discharges from construction sites, including ELGs and NSPSs. (67 FR 42644; June 24, 2002). On April 26, 2004, EPA chose to rely on the range of existing programs, regulations, and initiatives that already existed at the federal, state and local level and withdrew the proposed ELGs and NSPSs. (69 FR 22472; April 26, 2004). On October 6, 2004, the Natural Resources Defense Council, Waterkeeper Alliance and the states of New York and Connecticut filed a complaint in federal district court alleging that EPA's decision not to promulgate ELGs and NSPSs for the C&D point source category violated a mandatory duty under the CWA. The district court, in

NRDC

v.

EPA,

437 F.Supp.2d 1137, 1139 (C.D. Cal. 2006), held that CWA section 304(m) imposes on EPA a mandatory duty to promulgate ELGs and NSPSs for new industrial point source categories named in a CWA section 304(m) plan. At that time EPA argued that the district court should enter an order providing for a four-year schedule for EPA to promulgate the ELGs and NSPSs in order to allow the Agency the opportunity to collect additional data on the construction industry, additional data on stormwater discharges associated with construction activity, and to be able to have the time to solicit additional data based on comments received on the proposed regulation. The district court rejected EPA's proposed schedule, forcing the Agency to proceed under an accelerated schedule by enjoining EPA in an order to propose and publish ELGs and NSPSs for the C&D industry by December 1, 2008 and to promulgate and publish ELGs and NSPSs as soon as practicable, but in no event later than December 1, 2009. See

NRDC, et al.

v.

EPA,

No CV-0408307 (C.D. Cal.) (Permanent Injunction and Judgment, December 5, 2006). On appeal, the Ninth Circuit in

NRDC

v.

EPA,

542 F.3d 1235 (9th Cir. 2008) affirmed the district court's decision. Consistent with the district court order, EPA published proposed ELGs and NSPSs on November 28, 2008 (see 73 FR 72562) and is publishing final ELGs and NSPSs today.

IV. Overview of the Construction Industry and Construction Activities

The C&D point source category covers firms classified by the Census Bureau into two North American Industry Classification System (NAICS) codes.

• Construction of Buildings (NAICS 236) includes residential, nonresidential, industrial, commercial and institutional building construction.

• Heavy and Civil Engineering Construction (NAICS 237) includes utility systems construction (water and

sewer lines, oil and gas pipelines, power and communication lines); land subdivision; highway, street, and bridge construction; and other heavy and civil engineering construction.

Other types of entities not included in this list could also be regulated.

A single construction project may involve many firms from both subsectors. The number of firms involved and their financial and operational relationships may vary greatly from project to project. In typical construction projects, the firms identifying themselves as “operators” under a construction general permit are usually general building contractors or developers. While the projects often engage the services of specialty contractors such as excavation companies, these specialty firms are typically subcontractors to the general building contractor and are not separately identified as operators in stormwater permits. Other classes of subcontractors such as carpentry, painting, plumbing and electrical services typically do not apply for, nor receive, NPDES permits. The types and numbers of firms in the construction industry are described in more detail in the Economic Analysis.

Construction activity on any size parcel of land almost always calls for a remodeling of the earth. Therefore, actual site construction typically begins with site clearing and grading. Earthwork activities are important in site preparation because they ensure that a sufficient layer of organic material (ground cover and other vegetation, especially roots) is removed. The size of the site, extent of water present, the types of soils, topography and weather determine the types of equipment that will be needed during site clearing and grading. Material that will not be used on the site may be hauled away. Clearing activities involve the movement of materials from one area of the site to another or complete removal from the site. When grading a site, builders typically take measures to ensure that new grades are as close to the original grade as possible to reduce erosion and stormwater runoff, which can result in discharge of sediment, turbidity and other pollutants. Proper grade also ensures a flat surface for development and is designed to attain proper drainage away from the constructed buildings. A wide variety of equipment is often used during excavation and grading. The type of equipment used generally depends on the functions to be performed and on specific site conditions. Shaping and compacting of the earth is an important part of site preparation. Earthwork activities might require that fill material be used on the site. In such cases, the fill must be spread in uniform, thick layers and compacted to a specific density. An optimum moisture content must also be reached. Graders and bulldozers are the most common earth-spreading machines, and compaction is often accomplished with various types of rollers. If rock is to be removed from the site, the contractor must first loosen and break the rock into small pieces using various types of drilling equipment or explosives. (Adapted from Peurifoy, Robert L. and Oberlender, Garold D. (1989). Estimating Construction Costs (4th ed.). New York: McGraw Hill Book Company.)

Once materials have been excavated and removed and the ground has been cleared and graded, the site is ready for construction of buildings, roads, and/or other structures. During construction activity, the disturbed land can remain exposed without vegetative cover for a substantial period of time. Where the soil surface is unprotected, soil particles and other pollutants are particularly susceptible to erosion and may be easily washed away by rain or snow melt and discharged from the site. Permittees typically use a combination of erosion and sediment control measures designed to prevent mobilization of the soil particles and capture of those particles that do mobilize and become entrained in stormwater. In some cases permittees treat a portion of the discharge using filtration or other treatment technologies. Common erosion and sediment control measures and treatment technologies are described further in the Development Document.

V. Summary of the Proposed Regulation

EPA published proposed regulations for the C&D category on November 28, 2008. 73 FR 72562. The proposed rule contained several options. One option (Option 1), which is based on the requirements similar to those contained in past EPA CGPs, would have established a set of non-numeric effluent limitations requiring dischargers to provide and maintain effective erosion control measures, sediment control measures, and other pollution prevention measures to minimize, control or prevent the discharge of pollutants in stormwater and other wastewater from construction sites. In addition, reflecting current requirements in the EPA CGP, sediment basins would have been required for common drainage locations that serve an area with 10 or more acres disturbed at one time to contain and settle sediment from stormwater runoff before discharge. Option 1 would have required minimum standards of design for sediment basins; however, alternatives that control sediment discharges in a manner equivalent to sediment basins would have been authorized where approved by the permitting authority.

Another option (Option 2) would have incorporated the same provisions as Option 1 and for sites of 30 or more acres located in areas of the country with the annual Revised Universal Soil Loss Equation (RUSLE) R-factor greater than 50 and that contained more than 10% by mass of soil particles smaller than 2 microns, discharges of stormwater from the site would have been required to monitor and meet a numeric effluent limitation on the allowable level of turbidity. The numeric turbidity limitation proposed was 13 nephelometric turbidity units (NTUs). The technology basis for Option 2 was active or advanced treatment systems (ATS), which consisted of polymer-assisted clarification followed by filtration. A third option (Option 3) was similar to Option 2, except that it would have applied the 13 NTU limitation to all construction sites of 10 or more acres, regardless of location or soil type.

In addition, the proposal presented and solicited comment on another option that would require compliance with a higher numeric turbidity effluent limitation (e.g., 50 to 150 NTU, or some other value) based on passive treatment technologies instead of ATS (see 73 FR 72562, 72580-72582, 72610-72611). Passive treatment technologies include conventional erosion and sediment controls, polymer addition to sediment basins, fiber check dams with polymer addition, and other controls. At proposal, EPA sought additional data on the performance of passive treatment systems, and the cost and pollutant loading reductions that would be attainable from such an option.

In the proposed rule, EPA selected Option 1 as the basis of BPT and BCT, and Option 2 as the basis of BAT and NSPS. At the time of proposal, EPA defined a “new source” as any source from which there will be a discharge associated with construction activity that will result in a building, structure, facility, or installation subject to new source performance standards elsewhere under 40 CFR subchapter N.

A summary of the costs, estimated pollutant reductions, cost effectiveness and monetized environmental benefits of the proposed options are contained in the

Federal Register

notice for the proposed rule, in the support

documents for the proposed rule and in the record.

VI. Summary of Major Comments Received

EPA received numerous comments on the proposed rule. The majority of comments centered on EPA's selection of ATS as the technology basis for BAT and NSPS and the data and assumptions used to estimate the numeric limitation, costs and pollutant load reductions of the proposed BAT and NSPS. ATS is no longer the technology basis for BAT and NSPS in the final rule.

Some commenters argued that EPA's data used to estimate costs of the proposed option based on ATS did not accurately consider all of the costs, particularly for projects of longer duration. In response, EPA revised the model project analysis to consider projects of longer duration and utilized a unit-cost approach based on data contained in the record for the proposal.

Some commenters argued that EPA's analysis of the amount of construction activity underestimated actual levels of construction activity, since EPA's estimates were based on land use change estimates from 1992 to 2001 using the National Land Cover Dataset (NLCD). In response, EPA revised estimates of annual acres subject to the regulation using industry economic data instead of the NLCD data.

Some commenters argued that EPA's data and assumptions used to estimate loading reductions of the regulatory options did not accurately account for current controls in place nationwide. In response, EPA revised the assumptions used in the model to account for baseline controls. EPA also used data at the watershed level for some modeling parameters.

Some commenters requested that numeric limitations be based on, or consider, the background levels of sediment and turbidity in receiving streams when establishing a turbidity limitation. EPA notes that BAT and NSPS are based on the capabilities of technology, not receiving water quality. It would not be appropriate in establishing technology based effluent limitations pursuant to CWA sections 301 and 306 for EPA to consider the water quality of specific water bodies. See

Weyerhaeuser Co.

v.

Costle,

590 F.2d 1011, 1040-1044 (D.C. Cir. 1978). Permitting authorities have the ability to develop water-quality based effluent limitations to address receiving water concerns. Some states have set limitations for specific projects considering the background turbidity of the receiving waters. Commenters further argued that discharges of low turbidity water to streams that are naturally high in turbidity could contribute to stream instability. EPA does not agree with this comment. The particles contained in stormwater discharges from construction sites are primarily fine-grained, since sediment controls remove the bulk of the coarser particles. These fine-grained particles are not beneficial from a stream stability standpoint. Therefore, removal of these particles from the stormwater discharge would not be expected to further contribute to stream instability, if the receiving stream was already unstable. It is plausible that discharge of a large volume of stormwater over a short period of time to a small stream with a high natural sediment load could contribute to instability. If this condition were to exist, it could be alleviated simply by controlling the rate of discharge or by dispersing runoff to vegetated areas on site, if available (see also, comment by Dr. Britt Faucette, EPA-HQ-OW-2008-0465-0527 in the rulemaking record).

Some commenters argued that some of the data EPA used to determine the numeric effluent limitation based on ATS should not be used because EPA lacked specific information on factors, such as type of construction project or treatment system configuration. Commenters also argued that the data was not representative, since these data were primarily from the Northwest United States. EPA does not agree with these comments. The data represent a variety of project types. Although EPA may not have detailed information about specific aspects of some projects (such as project size and treatment system flow rate), EPA has conducted an engineering review of the data and determined that the data is representative. EPA has excluded data, where appropriate, to account for factors such as treatment system startup and variation outside of the range that EPA would consider indicative of proper operation. Details of the engineering review of the data can be found in the Development Document. In addition, EPA received additional information on some of the data, such as project type and treatment configuration. EPA also received data from additional projects, including projects in New York and North Carolina. More details on the data can be found in the administrative record.

Some commenters were concerned about the non-numeric effluent limitations proposed, and specifically questioned whether some of the proposed requirements could be implemented on all construction sites. EPA generally agrees that some of the requirements, as proposed, could not be implemented on all sites and made revisions to the non-numeric effluent limitations to make them applicable to all sites. For certain controls, EPA included “unless infeasible” to recognize that there may be some sites where a particular control measure cannot be implemented, thus allowing flexibility for permittees. (See Section X.B.)

Some commenters questioned the stringency of the proposed soil stabilization requirements, and were concerned about the costs and feasibility of initiating stabilization of disturbed area “immediately” when final grade is reached or any clearing, grading, excavating or other earth disturbing activities have temporarily or permanently ceased and will not resume for a period exceeding 14 calendar days. EPA disagrees that this requirement is not feasible. Given the importance of soil stabilization techniques (see Chapter 5 of the Technical Development Document (TDD)), and the influence of soil cover on soil erosion rates, EPA has determined that initiating soil stabilization measures immediately is an important non-numeric effluent limitation. EPA sees no compelling reason why permittees cannot take action immediately to stabilize disturbed soils on their sites. Erosion control measures, such as mulch, are readily available and permittees need only plan accordingly to have appropriate materials and laborers present when needed. EPA has, however, modified this requirement for clarity (see the final requirement at § 450.21(b).

EPA received comments concerning applicability of the final rule to linear construction projects, including the numeric effluent limitation. EPA considered the unique characteristics of linear projects in determining the appropriate technology based effluent limitations for those sites. The final rule, in part based on the considerations of linear projects, no longer contains a requirement to install a sediment basin (See Section VII.A), the technology basis for the numeric effluent limitation is no longer ATS (See Section X.G.3), and revisions were made to the non-numeric effluent limitations based on comments concerning the feasibility at linear projects. (See Section X.B.2). EPA disagrees with comments that suggested EPA should either exempt all linear projects from the final rule or from the numeric effluent limitation. EPA has determined that numeric effluent limitations are feasible for linear projects and passive treatment systems provide flexibility to linear projects to

take into account site specific considerations. (See the TDD for specific examples of the utilization of passive treatment systems at linear projects). Additionally, EPA believes that the permitting authority should exercise discretion when determining the monitoring locations and monitoring frequency for linear construction projects. (See Section XIX.A).

Based on the unique regulatory circumstances of interstate natural gas pipeline construction projects EPA has chosen not to have the numeric limitation and monitoring requirements at 40 CFR 450.22(a) apply to the discharges associated with the construction of natural gas pipelines. This exemption only applies to discharges associated with construction of interstate natural gas pipelines that are under the jurisdiction of the Federal Energy Regulatory Commission (FERC). EPA determined this was appropriate due to the comprehensive regulatory program that FERC requires and enforces for the construction of these projects. Through its program, FERC requires a variety of erosion and sediment controls to be implemented during construction, some of which are more stringent than those contained in today's rule. FERC conducts site-specific reviews to establish the allowable area of disturbance for project construction and dictates the manner in which construction of these projects can proceed. Typical requirements would include minimizing the amount of time that soils are allowed to be exposed, managing the discharges from trench dewatering, limiting the amount of vegetation that can be cleared adjacent to streams and wetlands, and requiring successful revegetation of project areas. FERC has been requiring these projects to implement its erosion and sediment control program since 1989. Thus, it is a well-developed regulatory program that includes stringent requirements, oversight, public participation, and onsite inspection. EPA does not want to limit the flexibility of FERC to implement its program by imposing numeric limitations on these unique projects.

EPA received comments encouraging the Agency to include controls in the final rule on stormwater discharges that occur after construction activity has ceased or what they call “post-construction” stormwater discharges. These discharges are outside the scope of the final rule; however the Agency understands that there is a need to address discharges from newly developed and redeveloped sites, such as commercial buildings, roads, or parking lots, in order to protect the water quality of our nation's waters. As the urban, suburban and exurban human environment expands, there is an increase in impervious landcover and stormwater discharges. This increase in impervious landcover on developed property reduces or eliminates the natural infiltration of precipitation. The resulting stormwater flows across roads, rooftops and other impervious surfaces, picking up pollutants that are then discharged to our nation's waters. In addition, the increased volume of stormwater discharges results in the scouring of rivers and streams; degrading the physical integrity of aquatic habitats, stream function and overall water quality. In July 2006, EPA commissioned the National Research Council (NRC) to review the Agency's program for controlling stormwater discharges under the CWA and recommend steps the Agency should take to make the stormwater program more effective in protecting water quality. The NRC Report

Urban Stormwater Management in the United States

(DCN 42101) states that stormwater discharges from the built environment remain one of the greatest challenges of modern water pollution controls, “as this source of contamination is a principal contributor to water quality impairment of waterbodies nationwide.” The NRC report found that the current regulatory approach by EPA under the CWA is not adequately controlling all sources of stormwater discharges that are contributing to waterbody impairment. NRC recommended that EPA address stormwater discharges from impervious landcover and promote practices that harvest, infiltrate and evapotranspirate stormwater to prevent it from being discharged, which is critical to reducing the pollutant loading to our nation's waters.

EPA has committed to and begun a rulemaking addressing stormwater discharges from newly developed and redeveloped sites under CWA section 402(p). EPA has published a draft Information Collection Request, 74 FR 56191 (October 30, 2009) for public comment that will seek information and data to support the rulemaking, and plans to complete this rule in the fall of 2012.

Some commenters argued that turbidity is not a “pollutant” under the CWA. EPA disagrees with the commenters as turbidity is a “pollutant” under the CWA and an indicator for other pollutants and is the appropriate pollutant in this rule to control, under the appropriate levels of technology, for discharges from C&D sites. In this rule, turbidity is being regulated as a nonconventional pollutant and as an indicator pollutant for the control of other pollutants in discharges from C&D sites including metals and nutrients. By providing a measure of sediment and other pollutants in discharges, turbidity is an indicator of the degree to which sediment and other pollutants found in discharges are reduced. Turbidity is also a more effective measure of the presence of fine silts and clays and colloids, which are the particles in stormwater discharges that EPA is primarily targeting in today's rule.

Turbidity is a pollutant as that term is defined in the CWA. See

e.g., Conservation Law

Foundation

v.

Hannaford Bros. Co.,

327 F.Supp.2d 325, 326 (D.Vt. 2004), aff'd 139 Fed.Appx. 338 (2d.Cir. 2005). The CWA defines “pollutant” broadly to include “dredged spoil, solid waste, incinerator residue, sewage, garbage, sewage sludge, munitions, chemical wastes, biological materials, radioactive materials, heat, wrecked or discarded equipment, rock, sand, cellar dirt and industrial, municipal and agricultural waste.” CWA section 502(6).

See NRDC

v.

EPA,

822 F.2d 104, 109 (D.C.Cir. 1987) (“The term `pollutant' is broadly defined…”);

U.S.

v.

Hamel,

551 F.2d 107, 110 (6th Cir. 1977) (noting that the definition is set forth in “broad generic terms.”). EPA describes “turbidity” as “an expression of the optical property that causes light to be scattered and absorbed rather than transmitted with no change in direction of flux level through the sample caused by suspended and colloidal matter such as clay, silt, finely divided organic and inorganic matter and plankton and other microscopic organisms.” 40 CFR 136.3; 72 FR 11200, 11247 (March 12, 2007). Turbidity fits easily into the broad definition of pollutant. The definition of pollutant is not limited to those terms that are specifically listed in the statute at section 502(6). See

NWF

v.

Gorsuch,

693 F.3d 156, 174 n.56 (D.C. Cir. 1982);

Sierra Club

v.

Cedar Point Oil Co.,

73 F.3d 546, 565 (5th Cir. 1996).

Turbidity is also an indicator or measurement of other pollutants in the water body; however merely because turbidity measures other pollutants or can be an expression of the condition of the water body, does not mean it is not itself a “pollutant” under the CWA. There are numerous other pollutants, some that Congress explicitly included in the CWA, that are also indicators or measurements of other pollutants. For example, the CWA lists biochemical oxygen demand (BOD) and pH as pollutants. CWA section 304(a)(4). BOD is the measure of the amount of oxygen required by bacteria for stabilizing

material that can be decomposed under aerobic conditions and pH is a measure of how acidic or basic a substance is. Additionally, chemical oxygen demand (COD) is a pollutant and a measurement of other pollutants. See

BASF Wyandotte

v.

Costle,

598 F.2d 637, 651 (1st Cir. 1979). Even total suspended solids (TSS) are a measure of the organic and inorganic particulate matter in wastewater. Like turbidity, there is no question BOD, pH, COD and TSS are pollutants and there is no conflict between a pollutant being a measurement of other pollutants and a pollutant itself under the CWA.

One commenter argued that turbidity is a direct representation of TSS, thus, if anything, turbidity can only be used as a surrogate for TSS, and thus a conventional pollutant. In 1978 EPA interpreted “suspended solids,” at section 304(a)(4), as “total suspended solids (non-filterable) (TSS).” EPA defined TSS as “a laboratory measure of the organic and inorganic particulate matter in wastewater which does not pass through a specified glass filter disk.” See 40 CFR 401.16; 43 FR 32857, 32858 (July 28, 1978). The terms turbidity and TSS are related to sediment and are analogous, but they are not synonymous pollutants or measures of water quality. TSS and turbidity are measured differently, as turbidity is a measure of the light scattering properties of the sample measured as NTU and TSS is generally a measure of the concentration (i.e., milligrams per liter). The size, shape, and refractive index of suspended particulate matter are not directly related to the concentration and specific gravity of the suspended matter. Therefore, measurements of TSS and turbidity are not interchangeable. Pollutants that are not identified as either toxic or conventional pollutants are nonconventional pollutants under the CWA. See CWA section 301(b)(2)(F); 304(a)(4); 40 CFR 401.16;

Rybacheck

v.

EPA,

904 F. 2d 1276, 1291-92 (9th Cir. 1990). CWA section 304(a)(4) identifies what pollutants are conventional pollutants under the CWA, namely biochemical oxygen demand, suspended solids, fecal coliform, and pH, with EPA adding oil and grease. See also, 40 CFR 410.16; 44 FR 44501 (July 30, 1979). Turbidity is not identified as a conventional pollutant in the CWA or been identified as one by EPA. In the proposal, EPA cited to

Rybachek

v.

EPA,

904 F.2d at 1291-92, to demonstrate an analogous situation where it was argued that “settleable solids” were a component of TSS, or in other words, they are the same pollutant, thus EPA should have classified settleable solids as a conventional pollutant rather than a nonconventional pollutant. Id. at 1291. The Ninth Circuit, agreeing with EPA's analysis in that case and the discussion above, concluded that “because settleable solids were not designated by Congress as either conventional or a toxic pollutant, they should be considered a nonconventional pollutant under [section 301(b)(2)(F)].” Id. at 1292. EPA applied a similar analysis to turbidity to conclude that it is a nonconventional pollutant under the CWA.

Commenters' focus on arguing that turbidity is not a pollutant, or at the very least a conventional pollutant, may be based on a desire for a different technology standard applied to this rulemaking (

i.e.,

BCT). However, even if EPA did agree that turbidity is not a pollutant or is a conventional pollutant, TSS and turbidity are not the only pollutants of concern in discharges from C&D sites. Metals, nutrients, and other toxic and nonconventional pollutants are naturally present in soils, and can be contributed during construction activity or by activities that occurred at the site prior to the construction activity (see,

e.g.,

comment from Dr. Britt Faucette, EPA-HQ-OW-2008-0465-0527 in the rulemaking record. EPA recognizes that its understanding of the nature of stormwater discharges associated with construction activity has evolved. However, as early as 1990, in the Phase I stormwater rulemaking EPA identified nonconventional and toxic pollutants of concern in discharges from construction sites stating “[c]onstruction sites can also generate other pollutants such as phosphorus, nitrogen, and nutrients from fertilizer, pesticides, petroleum products, construction chemicals and solid wastes.” 55 FR at 48033. The National Academy of Sciences agrees with EPA and the NRC report states “[t]he pollutant parameters of concern in stormwater discharges from construction activity are TSS, settleable solids, turbidity, and nutrients from erosion; pH from concrete and stucco; and a wide range of metallic and organic pollutants from construction materials, processes, wastes, and vehicles and other motorized equipment.” NRC at 541. EPA is making clear in this final rule that while conventional pollutants are a concern in discharges from construction sites, there are also nonconventional and toxic pollutants of concern in discharges from these sites. Many of these pollutants are present as particulates and will be removed with other particles. Dissolved forms of pollutants are often absorbed or adsorbed to particulate matter and can also be removed along with the particulates (i.e., sediment). See the Environmental Assessment document for additional discussion about pollutants found in discharges from C&D sites.

Additionally, stormwater discharges from C&D sites in their entirety are “industrial waste,” a nonconventional pollutant under the CWA, thus EPA is not obligated to single out specific constituents or parameters in the discharge. See

Northern Plains Resource Council

v.

Fidelity Exploration and Development Co.,

325 F.3d 1155 (9th Cir. 2003). Due to stormwater discharges being, or including, nonconventional or toxic pollutants, EPA is statutorily obligated to promulgate a BAT level of control for these point source discharges. CWA section 301(b)(2)(A). EPA is also statutorily obligated to promulgate a best available demonstrated control technology (BADT) for NSPS for

all

pollutants from new sources, even if the only pollutants from C&D sites were conventional pollutants.

Some commenters urged EPA to establish numeric effluent limitations for pollutants other than turbidity (such as pH). While EPA agrees there are other pollutants of concern that are discharged from construction sites the Agency determined it is not necessary to establish any other numeric effluent limitations at this time. Many of the pollutants of concern are sediment-bound pollutants, such as metals and nutrients. The non-numeric effluent limitations in the final rule will address the mobilization of sediment and the discharge of these sediment-bound pollutants. The final rule includes a non-numeric effluent limitation that prohibits the discharge of wastewater from washout of concrete, unless managed by an appropriate control. 40 CFR 450.21(3)(1). This requirement was included to specifically address concerns with pH. Additionally, the numeric effluent limitation, in addition to controlling the discharge of turbidity, will control the discharge of some of these other pollutants of concern. If permitting authorities have concerns regarding the discharge of other pollutants they may be addressed with numeric effluent limitations on case-by-case basis through NPDES permits.

Some commenters noted that they believed there may be environmental risks of applying polymers during construction activity to control discharges of pollutants from C&D sites due to what commenters believed was the potential for the polymers to cause fish kills or otherwise cause an adverse

effect in the receiving waters. At proposal EPA had no specific examples of the use of treatment chemicals causing fish kills or aquatic toxicity, although anecdotal evidence did exist (see DCN 41110). In the proposal, EPA specifically requested information and data that quantified the number of instances where overuse of polymers occurred, the circumstances resulting in such overuse, and the actual or potential environmental impacts associated with such events. 73 FR at 72573; see also 73 FR at 72610. EPA received one specific comment regarding a fish kill associated with the use of ATS (see EPA-HQ-OW-2004-0465-1287 in the rulemaking record) and one comment that referenced “significant environmental harm” resulting from the use of chitosan or other chemicals, although specific details were not provided (see EPA-HQ-OW-2008-0465-0973 in the rulemaking record). One commenter also stated that during pilot testing of two ATS systems that “chemical overuse and poor operation never purposefully occurred, but happened anyway.” This commenter also noted, when comparing ATS usage during this pilot testing to ATS that is used in Washington State that “the treatment system used on the Idaho site was missing many features that made it easier and environmentally safer to operate. The operator did not have the level of training required in Washington. DEQ did not come close to the amount of staff time Washington spends overseeing the operation of these systems and DEQ did not have any staff trained to assess if the system was being operated correctly.” (see EPA-HQ-OW-2008-0465-1269 in the rulemaking record.

A number of coagulant and flocculants, including polymers, are available on the market and are in wide use for the control of pollutants, not only on construction sites, but to reduce sediment from agricultural fields and to reduce pollutants in discharges from wastewater treatment plants to name a few. While successful in reducing sediment and turbidity in conveyance systems, polymers and other additives should be carefully utilized in passive treatment systems. Several states have approved specific formulations for use on construction sites and EPA will work with the permitting authorities and the construction industry to ensure the proper application of polymers and other additives, if necessary, before owners and operators of construction sites are required to meet the numeric effluent limitation. Knowledge from toxicity studies suggest that polymers are highly variable as to their toxic effects on aquatic organisms (see discussion of toxicity in the Environmental Assessment). States have approved the use of polymers and other additives at construction sites, for example, Washington State has approved chitosan, a cationic polysaccharide biopolymer, for certain uses and has seen wide use in water and stormwater treatment. Therefore, the use of specific compounds should be considered by the permitting authority and owners and operators of construction sites in light of various environmental influences. While EPA recognizes that there is the potential for problems due to improper application of polymers, EPA has determined that when properly used, environmental impacts from polymers or flocculants should not occur through the use of passive treatment systems. The dose ranges where polymers are utilized on construction sites are well below the chronic toxicity levels. The utilization of polymers on construction sites has occurred for a significant period of time and they are currently being used on construction sites throughout the nation. EPA recognizes the merits of ensuring that polymers or other chemical additives, if necessary, are properly used. Permitting authorities should carefully consider the appropriateness of usage of these materials where there are sensitive or protected aquatic organisms in the receiving waters, including threatened or endangered species and their critical habitat. NPDES permitting authorities may establish controls on dosage and usage, protocols for residual toxicity testing, require prior approval before the use of particular polymers, training requirements for site operators or other measures they deem appropriate. In addition, permittees can also specify, and permittees may choose to utilize, on-site infiltration or dispersion to vegetated areas in combination with, or in place of, polymer-based systems. See 73 FR 72562, 72573-74. Based on the information in the record EPA has determined that when polymers are properly applied the risks of toxicity to aquatic life or adverse effects to the receiving water are minimal. However, it is important that permittees be properly trained in the use of polymers. Operators of C&D sites need to have expertise in a number of technical areas, including engineering, stormwater management and implementation of erosion and sediment controls. Technical specialists, such as engineers, hydrologists and soil scientists are involved in many aspects of site design and construction activity. Permittees typically have engineers on staff, or employ consultants to prepare plans, supervise construction and conduct inspections of various aspects of the project. Given that construction activities require rigorous attention to safety and engineering specifications, there is a reasonable basis for EPA to expect that operators can conform to proper operation and maintenance of controls and proper use of polymers and flocculants. The erosion and sediment control and stormwater management industries are large and composed of diverse specialties. There are several national trade and professional organizations whose members are engaged in various aspects of erosion and sediment control and stormwater management and who have an active role in conducting research and technical outreach. EPA believes that there is a range of expertise available across the industry to properly implement controls that may be required to meet a numeric limitation. Also, sampling and compliance with the turbidity limitation is not required until 18 months after the effective date of this final rule for sites with 20 or more acres of disturbed land at one time and four years after the effective date of the final rule for sites with 10 or more acres of disturbed land at one time. This will allow permittees time to obtain any necessary training if they do not already have trained personnel on staff and for the permitting authorities to provide guidance to permittees.

VII. Summary of Significant Decisions and Revisions to Analyses

EPA solicited comments on a number of issues in the proposed rule. Two areas that EPA specifically requested comments on were the regulatory options proposed as well as the data used to estimate the costs, pollutant loading reductions, environmental benefits and economic impacts of various options. Based on comments received, EPA revised the regulatory options that were proposed and further developed a regulatory option that would establish a numeric limitation based on passive, rather than active, treatment at construction sites. EPA used data collected in support of the proposed regulation, data submitted during the public comment period and by the public after the close of the comment period, as well as additional data collected by EPA to estimate costs, environmental benefits and economic impacts for this option. EPA also updated its costs and economic analyses with these new data to revise the estimates for the proposed options. EPA

also revised what C&D sites may be new sources and covered by NSPS. This section summarizes the principle regulatory options considered for the final rule and the revisions that were made to EPA's analyses following proposal.

A. Regulatory Options

In considering options for the final rule, EPA revised the proposed regulatory options in several ways. First, comments received by state environmental agencies, Departments of Transportation (DOTs), the U.S. DOT, and other members of the public indicated that sediment basins are not common practice on all larger construction sites, particularly on linear projects such as road and highway construction. The reasons provided by commenters included the lack of available space within the project right of way as well as the preference to use distributed controls on some sites instead of centralized drainage at sites. Commenters also stressed the need to allow engineers and other professionals that are designing erosion and sediment control plans to choose practices that reflect site-specific factors, and that mandating basins for larger sites would limit that flexibility. Commenters also suggested that active treatment, which typically involves construction of storage basins, was a disincentive to using distributed stormwater controls to manage long-term stormwater discharges from newly developed and redeveloped sites. If permittees construct sediment basins, according to commenters, they are more likely to retain these basins as part of the long-term stormwater management controls. EPA agrees with a number of these comments, particularly the need to give professionals the flexibility to design site-specific controls. Therefore, EPA deleted the sediment basin sizing requirements that were contained in the proposed Options 1, 2 and 3 when considering options for the final rule. Commenters also indicated that the soil clay content provisions proposed by EPA for Option 2 would be difficult to implement, given the variation in soils present at construction sites and the fact that imported soils are often used for fill material. A concern was also raised on the practical applicability of the clay content provision to linear construction projects that may exist over large geographic areas. Therefore, determination of whether or not a particular project would meet the soil clay content thresholds would be difficult for owners and operators of construction sites. EPA agrees with commenters on this issue. Therefore, EPA deleted the soil clay content threshold from Option 2. Commenters also suggested that the R-factor criteria proposed under Option 2 would represent one more unnecessary complexity to the regulation, and that the site size criteria should be based on the disturbed area of the site, not the total project size since stormwater discharges from disturbed areas are the primary discharges containing pollutants. EPA agrees with these suggestions. Therefore, EPA also deleted the R-factor criteria from Option 2. The revised Option 2 would apply to any site that met the disturbed acreage size threshold, regardless of soil type and R-factor.

Comments from the potentially regulated industry and states on the proposal did not favor the use of ATS as the technology basis for a national turbidity limitation. There were a number of reasons given, but the most prominent included the costs, availability and feasibility of ATS. While EPA does not agree with all of these comments, the Agency further evaluated data available to support a numeric turbidity limitation based on technologies other than ATS, including techniques that incorporate either liquid or solid forms of polymer. Examples include liquid polymer dosing of sediment basins, passive dosing in channels through the use of polymer gel socks or floc-blocks or floc-logs, and application of polymer to fiber check dams. EPA also evaluated data available for the placer mining industry. EPA determined that a numeric turbidity limitation based on these and other passive treatment techniques are technically available. As a result, EPA further explored this option and looked at site size thresholds of 1, 5 and 10 acres of disturbed land at one time as potential applicability criteria for a technology-based numeric limitation based on passive treatment.

EPA also received numerous comments about the feasibility of many of the erosion and sediment control and pollution prevention provisions contained in Options 1, 2 and 3. EPA generally agrees that some of these requirements, as proposed, could not be implemented on some construction sites. As a result, EPA made several changes to these provisions which are described in more detail in section X.B.

B. Cost Analysis

EPA received several comments regarding the costs of ATS and the methodology used by EPA to determine costs of the regulatory options. While EPA believes some of these comments have technical merit, EPA found that some commenters greatly overestimated the likely actual costs to implement ATS. Key points made by commenters included (1) that the methodology used at proposal, which was based on a flat cost per gallon to treat, likely did not capture the actual costs of ATS in some applications and in some areas of the country; (2) that the methodology did not factor in the longer duration of some projects (particularly larger residential projects); and (3) the methodology for estimating the size of the industry, which was based on land use change data from 1992 to 2001, likely did not accurately predict the level of construction activity in the near future that would be expected under normal business conditions (i.e., not reflective of the current downturn in the industry), which is the primary analysis case upon which EPA based costs and economic impacts (see discussion in Section XII). EPA has revised and updated the methodology used to estimate the costs of ATS and the expected amount of construction activity to reflect these and other points. The revised analysis significantly increased costs for the revised Options 2 and 3. In the updated methodology, EPA first used data submitted by vendors to develop a series of one-time and monthly costs for ATS. Secondly, EPA estimated the expected amount of construction activity using long-term industry economic data. EPA then estimated the expected duration of projects of varying site size and project types using permit Notice of Intent (NOI) data from approximately 22,000 permit applications from 4 States for construction activities occurring primarily between 2003 and 2009. The combination of all three of these factors (a unit costing approach, longer durations for some projects and a higher estimate of total acres being developed) resulted in significantly higher costs for the revised Options 2 and 3 than were estimated at the time of proposal. Moreover, the cost of the revised Option 2 increased over the proposed Option 2 because EPA removed the R-factor and soil type criteria of proposed Option 2, thereby increasing the number of projects covered by revised Option 2. Additional details can be found in the Development Document and in the Economic Analysis.

C. Pollutant Load Analysis

EPA received several comments on the pollutant loading analysis contained in the proposal, primarily stating that EPA overestimated baseline pollutant loadings and the reductions due to Options 2 and 3 because the assumptions used in EPA's model did

not accurately account for current industry practices. EPA generally agrees with some of these comments, and has revised the assumptions used in the model. EPA also used a more detailed analysis of loads for the final rule that uses watershed-specific data for some of the model parameters. The result of these changes is that the load reduction estimates for Options 2 and 3 have decreased since proposal. Additional details on the new assumptions and the results of EPA's analysis can be found in Section XV and in the Development Document.

D. Economic Analysis

The primary revisions to the economic analysis were updates to the approach to developing model projects and then the assignment of project costs to model firms. EPA revised the model projects to include a set of 288 model projects, based on 12 different size categories, 12 duration categories, and two project types (building, transportation). EPA also accounted for the effect that different climate and soil conditions can have on control costs by considering variation in rainfall and runoff factors for each state. This resulted in 14,688 model projects with potentially different costs. These model projects were then combined with activity estimates to develop an estimated 84,000 individual model projects.

Another revision to the economic analysis was the way in which project costs were assigned to firms. For the proposal, project costs were used to develop a weighted average cost per acre for each state. These weighted average costs were then assigned to model firms based on the estimated number of acres they construct on per year. For the final rule, each of the 84,000 projects and their associated costs were assigned to firms. This assignment was based on each category of model firm's capacity to perform projects of various size and duration.

EPA also made changes to the adverse case analysis and the analysis of future costs. EPA received comments that the data used to represent adverse business conditions for the adverse case analysis did not adequately represent the most recent conditions for the industry, which are less favorable. EPA addressed this concern by updating the adverse analysis industry financial profile with 2008 Value Line financial data. For the future costs analysis, EPA was able to use future revenue projections published by Global Insights, to estimate year to year changes in acreage developed, the total number of projects and the number of projects subject to various rule requirements. This allowed for an assessment of changes in the number of firm and employment impacts from year-to-year.

EPA made two adjustments to the housing affordability analysis. For the proposal, EPA evaluated the effect of the proposed options on the price of the median and lower quartile homes. For the final rule, EPA evaluated the impacts of potential price increases for a new home selling for $100,000 and $50,000 to better reflect the impact of price increases at the very low end of the market for new housing. For the proposal, all new home buyers were assumed to buy the most expensive house they could qualify to purchase. However, for the final rule EPA was able to use data from the American Housing Survey, to estimate the average percentage of household income typically spent on a home purchase, for various income ranges. This allowed for a more realistic assessment of the number of home buyers who may have difficulty affording a new home after a price increase.

E. Benefits Estimation and Monetization

Although EPA is not required by statute to quantify environmental benefits for ELGs and NSPSs, EPA did quantify and monetize benefits of the regulatory options to comply with Executive Order 12866. EPA solicited comments on the proposed approach. EPA received comments on the approach and made revisions in order to improve upon the estimates prepared at proposal. Soil on construction sites contains a number of pollutants beyond sediment and turbidity. EPA estimated the degree to which the regulatory options would decrease nitrogen and phosphorus levels in receiving surface waters, and estimated associated water quality impacts using the nitrogen and phosphorus versions of the Spatially Referenced Regressions on Watershed Attributes (SPARROW) model. EPA used these estimates to inform the estimation of the degree to which the public is willing to pay for water quality improvements associated with the regulatory options, which in turn was utilized in EPA's monetized benefits analysis.

EPA expanded the set of potentially impacted waters to include a subset of the nation's estuaries. This enabled the agency to analyze the degree to which the public is willing to pay for improvements in estuarine water quality. EPA utilized this information in conjunction with available data on improvements in estuarine water quality associated with each of the regulatory options in order to monetize benefits associated with those options.

EPA also made refinements to the Water Quality Index (WQI) used for mapping pollution parameter changes to effects on human uses and support for aquatic and terrestrial species habitat. Implementation of the WQI involves transforming the measurements of parameter, such as TSS, nitrogen, and phosphorus, into sub-index values that express water quality conditions on a common scale of 0 to 100. For the pollutant TSS, a unique sub-index curve was developed for each of the 85 Level III ecoregions using baseline TSS concentrations calculated in SPARROW at the enhanced Reach File 1 (RF1) level (see Section XV). In addition, at proposal, EPA did not quantify projected reductions in nutrient loadings as a result of the rule, but these were included in the final rule analysis, including the assessment of changes in the WQI.

VIII. Characteristics of Discharges Associated With Construction Activity

Construction activity typically involves clearing, grading, excavating and other land-disturbing activities. Prior to construction activity, these land areas may have been agricultural, forested or other undeveloped lands. Construction activity can also occur as redevelopment of existing rural or urban areas, or infill development on open space within existing developed areas. The nature of construction activity is that it changes, often significantly, many elements of the natural environment. As described earlier, construction activities typically involve clearing the land of vegetation, digging, and earth moving and grading, followed by the active construction period when the affected land is usually left denuded and the soil compacted, often leading to an increase in the peak discharge rate and the total volume of stormwater discharged and higher rates of erosion. During the land disturbance period, affected land is generally exposed after removal of grass, rocks, pavement and other protective ground covers. Where the soil surface is unprotected, colloids, silt, clay and sand particles may be easily picked up by wind and/or washed away by rain or snow melt.

Stormwater discharges can have variable levels of pollutants. Available data show that turbidity levels in discharges from construction sites range from as low as 10-50 NTU to tens of thousands of NTU. When the denuded and exposed areas contain nutrients, pathogens, metals or organic compounds, these other pollutants are carried at increased rates (relative to

discharges from undisturbed areas) to surrounding waterbodies via stormwater and other discharges (e.g., inadequately controlled construction equipment wash water). Discharges of these pollutants from construction activities can cause changes in the physical characteristics of waterbodies, such as pH or water temperature as well as changes in biological characteristics such as aquatic species abundance, health and composition. Changes in stream flow regime can also occur due to deposition of sediment, as well as the altered watershed hydrology resulting from soil compaction and loss of infiltrative capacity.

Discharges from C&D sites associated with construction activity have been documented to increase the loadings of several pollutants in the receiving water bodies. The most prominent and most widespread pollutants of concern discharged from C&D sites are turbidity, suspended solids, total suspended solids (TSS), and settleable solids. Each of these pollutants are indicators of solids contained in the discharge (which, in the case of stormwater discharges associated with construction activities, are primarily due to soil particles), and each of these measures quantify different fractions of these solids.

Discharges associated with construction activity are also expected to contain varying concentrations of metals and toxic organic compounds, some of which may be contributed by equipment used onsite for grading and other construction activities, as well as various construction materials used on-site (such as asphalt sealants, copper flashing, roofing materials, adhesives, and concrete admixtures). Metals are also naturally present in soils and, by removing vegetative cover and increasing erosion and sediment loss, there will likely be an increase in the amount of metals discharged from the C&D site. Metals can also be present as a contaminant from previous activity on the site (such as may occur in redevelopment of industrial areas) or as a contaminant or additive in fertilizers and other soil amendments. Fuels and lubricants are maintained onsite to refuel and maintain vehicles and equipment used during construction activities. These products, should they come in contact with stormwater and other site discharges, could contribute toxic organic pollutants. Pathogenic pollutants can be present in stormwater that comes into contact with sanitary wastes where portable sanitation facilities are poorly located or maintained. Also, trash and other municipal solid waste can be carried away by stormwater.

Nutrients can be present in construction site discharges, either as naturally-occurring components of the soil or due to previous activities on the site, such as enrichment due to agricultural activities. In addition, activities during construction activity, such as hydroseeding, can increase nutrients levels in the soil.

IX. Description of Available Technologies

A. Introduction

As described in Section VIII, construction activity results in the discharge of pollutants to waters of the U.S. These discharges can be controlled by applying site design techniques that preserve or avoid areas prone to erosion and through the effective use of a combination of erosion and sediment control and pollution prevention measures. Construction activities should be managed to reduce erosion and retain sediment and other pollutants in the soil at the C&D site. Erosion and sedimentation are two separate processes and the practices to control them differ. Erosion is the process of wearing away of the land surface by water, wind, ice, gravity, or other geologic agents. Sedimentation is the deposition of soil particles, both mineral and organic, which have been transported by water, wind, air, gravity or ice (adapted from North Carolina Erosion and Sediment Control Planning and Design Manual, September 1, 1988).

Erosion control measures are intended to minimize dislodging and mobilizing of sediment particles. Sediment control measures are controls that serve to capture particles that have mobilized and are entrained in stormwater, with the objective of removing sediment and other pollutants from the stormwater discharge. An overview of available technologies and practices is presented below; see the Development Document for more complete descriptions. Many states and local governments and other entities have also published detailed manuals for erosion and sediment control measures, and other stormwater management practices.

B. Erosion Control Measures

The use of erosion control measures is widely recognized as the most important means of limiting soil detachment and mobilization of sediment. The controls described in this preamble are designed to reduce mobilization of soil particles and minimize the amount of sediment and other pollutants entrained in discharges from construction activity. Erosion can be minimized by a variety of practices. The selection of control measures that will be most effective for a particular site is dictated by site-specific conditions (e.g., topography, soil type, rainfall patterns). The main strategies used to reduce erosion include minimizing the time bare soil is exposed, preventing the detachment of soil and reducing the mobilization and transportation of soil particles off-site.

Decreasing the amount of land disturbed can significantly reduce sediment detachment and mobilization directly from ground disturbance or indirectly through changes in overland flows. Minimizing site disturbance by minimizing the extent of grading and clearing is the most effective means of reducing sediment yield. This approach not only maintains some site vegetative cover but also minimizes the temporary and permanent alteration of the natural hydrology of the site and the receiving waters, thereby reducing the susceptibility of the receiving waters to long-term changes in channel incision and expansion which affects the basin's sediment regime. Short term reductions in sediment yield can also be accomplished by phasing construction so that only a portion of the site is disturbed at a time. Another effective approach is to schedule clearing and grading events to reduce the probability that bare soils will be exposed to rainfall. Many areas of the country have defined times during the year when the majority of rainfall (and hence erosion) occurs. By scheduling major earth disturbing activities outside of the rainy season, erosion can be significantly reduced.

Managing stormwater flows on the site can be highly effective at reducing erosion. Typical practices include actively managing off-site and on-site stormwater using diversion berms, conveyance channels and slope drains to avoid stormwater contact with disturbed areas. In addition, stormwater should be managed using energy dissipation approaches to prevent high runoff velocities and concentrated flows that are erosive. Vegetative filter strips are often considered as sediment controls, but they can also be quite effective at dissipating energy and reducing the velocity (and thus erosive power) of stormwater. Stormwater that is directed to vegetated areas can infiltrate, thus reducing or even eliminating the amount of stormwater discharged from a site, particularly for smaller storm events.

After land has been disturbed and construction activity has ceased on any portion of the site, exposed soils should

be covered and stabilized immediately. Simply providing some sort of soil cover on these areas can significantly reduce erosion rates, often by an order of magnitude or more. Vegetative stabilization using annual grasses is a common practice used to control erosion. Physical barriers such as geotextiles, straw, rolled erosion control products and mulch and compost are other common methods of controlling erosion. Polymers (such as PAM) and soil tackifiers are also commonly used. These materials and methods are intended to reduce erosion where soil particles can be initially dislodged on a C&D site, either from rainfall, snow melt or up-slope runoff.

The effectiveness of erosion control measures is dependent on periodic inspection and identification and correction of deficiencies (

e.g.,

after each storm event). Erosion control measures alone will not eliminate the mobilization of soil particles and such controls must often be used in conjunction with sediment control measures.

C. Sediment Control Measures

Despite the proper use of erosion control measures, some sediment detachment and movement is inevitable. Sediment control measures are used to control and trap sediment that is entrained in stormwater runoff. Typical sediment controls include perimeter controls such as silt fences constructed with filter fabric and compost filter berms. Trapping devices such as sediment traps and basins, inlet protectors and check dams are examples of in-line sediment controls. Sediment traps and basins are commonly used approaches for settling out sediment eroded from small and large disturbed areas. Their performance can be enhanced using baffles and skimmers, and additional removal can be accomplished by directing trap or basin discharges to a sand filter or to a vegetated area. Basin and trap performance can also be enhanced by using chemically-enhanced settling (e.g., polymer or flocculant addition). Typical chemicals used on construction sites include polyacrylamide (or PAM), chitosan, alum, polyaluminum chloride and gypsum. Polymers or flocculants are available in either liquid or solid form, and can be introduced at several points in the treatment train in order to increase sediment removal. Liquid chemicals can be introduced via a metering pump in a channel upstream of a basin, or can be sprayed onto the surface of a basin. Rainfall-driven systems can also be used to introduce liquid forms of chemicals into channels or basins. This configuration allows for operation on nights or weekends when construction personnel may not be present on-site.

Conveyances are often used to channelize and manage stormwater on construction sites, and check dams are often placed in channels to control flow velocities and to remove sediment through settling and filtration. Sediment removal by check dams can be enhanced by applying polymer to the check dam, or by placing a polymer enclosed in a permeable material, such as a gel sock, or solid forms sometimes referred to as a floc-block, in the channel. Floc-blocks and gel socks are effective when placed in channels just prior to a basin, a check dam or other structure or conveyance, where the water velocity will be slowed allowing the turbidity, sediment and other pollutants, along with the polymer, to settle out.

Sediment removal can be further enhanced by directing discharges from basins and channels, or by directing discharges through silt fences or filter berms into vegetation or other buffers between the site and surface waters to promote filtration and infiltration. Also, stormwater in basins or other impoundments can be dispersed to vegetated areas using spray or drip irrigation systems, allowing for filtration and infiltration.

Active treatment processes such as electrocoagulation and filtration can also be used to increase sediment removal. Electrocoagulation uses an electrical charge to destabilize particles, allowing removal by settling or filtration. Filtration can be accomplished by directing stormwater to a sand filter bed, or by pumping water through vessels filled with sand or other media. Tube settlers and weir tanks can also be utilized to aid in sediment removal. When discharges from sediment controls or active treatment processes are directed to vegetated areas and stormwater is dispersed and allowed to infiltrate, the amount of stormwater discharged from the site can be reduced, and in some cases the discharge can be eliminated.

More detailed descriptions of sediment and erosion control measures, use of polymers and flocculants and active treatment processes can be found in the Development Document.

D. Other Construction and Development Site Management Practices

Construction activity generates a variety of wastes and wastewater, including concrete truck rinsate, construction and demolition waste, municipal solid waste (MSW), trash, and other pollutants. Construction materials and chemicals should be handled, stored and disposed of properly to avoid contamination of runoff that is discharged from the site. While mobilization by stormwater is one mechanism by which these wastes may be discharged from C&D sites, pollutants may also be discharged if wastes or wastewaters are dumped into streams or storm drains. Pollutants, trash and debris may also be carried away by wind. Control of these wastes can be accomplished using a variety of techniques.

Site planning, sequencing of land-disturbing activities and phasing of construction activities are also important management practices. Limiting the amount of land disturbed at one time, as well as during the entire construction project, are perhaps some of the most effective practices to reduce the amount of sediment, turbidity and other pollutants in discharges. The longer exposed soil areas are left unprotected, the greater the chance of rainfall-induced erosion. Proper planning such that soil stabilization activities can occur in quick succession after grading activities have been completed on a portion of a site can greatly reduce the amount of sediment and turbidity discharged. In addition, limiting the amount of land that is “opened up” at one time to the minimum amount that is needed, as well as limiting soil compaction and retaining natural vegetation on the site, can greatly reduce erosion rates and help maintain the natural hydrology. Also, grading of the site to direct discharges to vegetated areas and buffers that have the capacity to infiltrate runoff can reduce the volumes of stormwater requiring management in sediment controls.

E. Performance Data for Passive Treatment Approaches

Passive treatment systems (PTS), as described in this notice, include a variety of practices that rely on settling and filtration to remove sediment, turbidity and other pollutants. Where necessary, PTS includes the use of polymers or other flocculants. Data in the literature indicate that PTS are able to provide a high level of turbidity reduction at a significantly lower cost than active treatment systems. Details on PTS used as a basis for developing the numeric effluent limitation are contained in the Development Document as well as in the administrative record. Several studies and data sources are also summarized here.

For example, McLaughlin (see DCN 41005) evaluated several modifications to standard sediment trap designs at the North Carolina State University Sediment and Erosion Control Research and Education Facility (SECREF). He evaluated standard trap designs as contained in the North Carolina Erosion and Sediment Control Manual utilizing a stone outlet structure as well as alternative designs utilizing a skimmer outlet and various types of porous baffles. Baffle materials tested included silt fence, jute/coconut and tree protection fence tripled over. Tests were conducted using simulated storm events in which sediment was added to stormwater at flows of 10 to 30 liters per second. McLaughlin found that a standard gravel outlet did not significantly reduce turbidity values. Average turbidity values in the basin were 843 NTUs, while average turbidity in the effluent was 758 NTUs using the standard outlet. Use of a skimmer instead of a standard gravel outlet reduced turbidity to an average of 353 NTUs. Additional tests were conducted to evaluate the addition of polyacrylamide (PAM) through the use of floc-blocks. Floc-blocks are a solid form of PAM which are designed to be placed in flowing water. They are typically anchored by a rope or by placing them in a mesh bag or cage either in open channels or in pipes. As the water flows over the floc-blocks, the PAM dissolves somewhat proportional to flow. The floc-blocks typically have substantial amounts of non-PAM components, which are intended to improve PAM release, maintain the physical integrity of the blocks and enhance PAM performance (McLaughlin—Soil Facts; Chemical Treatments to Control Turbidity on Construction Sites). McLaughlin found that addition of PAM to sediment traps resulted in average effluent turbidities of 152 NTUs using a rock outlet and 162 NTUs using a skimmer outlet. For one set of tests, use of a standard stone outlet along with PAM was able to attain an average effluent turbidity of 51 NTUs, while tests with jute/coconut mesh baffles with PAM were only slightly higher, at 71 NTUs.

Warner and Collins-Camargo (see DCN 43071) evaluated several innovative erosion and sediment controls at a full-scale demonstration site in Georgia as part of the Erosion and Sedimentation Control Technical Study Committee (known as “Dirt II”). The Dirt II project consisted, among other things, of field monitoring as well as modeling of erosion and sediment control effectiveness at construction sites. The demonstration site was a 50-acre lot in a suburban area near Atlanta where a school was being constructed. In total, 22.5 acres of the site was disturbed. A comprehensive system of erosion and sediment controls were designed and implemented to mimic pre-developed peak flow and runoff volumes with respect to both quantity and duration. The system included perimeter controls that were designed to discharge through multiple outlets to a riparian buffer, elongated sediment controls (called seep berms) designed to contain runoff volume from 3- to 4-inch storms and slowly discharge to down-gradient areas, multi-chambered sediment basins designed with a siphon outlet that discharged to a sand filter, and various other controls. Extensive monitoring was conducted at the site. For one particularly intense storm event of 1.04 inches (0.7 inches of which occurred during one 27-minute period), the peak sediment concentration monitored prior to the basin was 160,000 mg/L while the peak concentration discharged from the passive sand filter after the basin was 168 mg/L. Effluent turbidity values ranged from approximately 30 to 80 NTUs. Using computer modeling, it was shown that discharge from the sand filter, which flowed to a riparian buffer, was completely infiltrated for this event. Thus, no sediment was discharged to waters of the state from the sand filter for this event. For another storm event, a 25-hour rainfall event of 3.7 inches occurred over a 2-day period. Effluent turbidity from one passive sand filter during this storm ranged from approximately 50 to 375 NTU, with 20 of the 24 data points below 200 NTU. For a second passive sand filter, effluent turbidity ranged from approximately 50 to 330 NTU, with nine of 11 data points below 200 NTU. In estimating compliance costs for the rule, EPA assumed that most operators would use sediment basins or check dams with polymer addition to enhance settling, rather than a passive sand filter. The Warner study indicates that using a comprehensive suite of erosion and sediment controls, including a basin with a surface outlet coupled with an in-ground passive sand filter may be able to achieve comparable turbidity control to the technologies that EPA costed without relying upon the use of polymers or flocculants. EPA has not costed this approach for the rule, nor included this data in calculation of the numeric limitation.

There are other references in the literature describing the various types of PTS and the efficacy of these systems. One application of a PTS is to add liquid polymer, such as PAM, to the influent of a conventional sediment basin. This can be accomplished by using a small metering pump to introduce a pre-established dose of polymer in the influent pipe or channel. If the polymer is added in a channel far enough above the basin, then turbulent mixing in the channel can aid in the flocculation process. Otherwise, some sort of provision may need to be made to provide mixing in the basin to produce flocs. Polymers typically used in this particular application include PAM, chitosan, polyaluminum chloride (PAC), aluminum sulfate (alum) and gypsum.

The Auckland (New Zealand) Regional Council conducted several trials to evaluate the effectiveness of chemical flocculants and coagulants in improving settling of suspended sediment contained in sediment laden runoff from earthworks sites (DCN 42112). Trials were conducted using both liquid and solid forms of flocculants. Trials were initially conducted on two projects: a highway project and residential development. A follow-on study evaluated passive basin dosing at an additional site (see DCN 42102).

The highway project (ALPURT) evaluated both a liquid polymer system and solid polymers. Liquid polymers evaluated were alum and PAC and solid polymers evaluated were all polyacrylamide products (Percol AN1, Percol AN2 and Percol CN1). Bench tests indicated that AN2 performed best among the solid polymers and that both PAC and alum were effective in flocculating the soils present on the site.

Following bench testing of the polymers, liquid and solid dosing systems were developed. For the liquid dosing system, initial consideration was given to a runoff proportional dosing system which would include a weir or flume for flow measurement, an ultrasonic sensor and signal generating unit, and a battery-driven dosing pump. These components, together with costs for necessary site preparatory work, chemical storage tanks and a secure housing, were estimated to cost approximately $12,000 (1999 NZ $) per installation. An alternative system was developed that provided a chemical dose proportional to rainfall. This rainfall-driven system, which did not require either a runoff flow measurement system or a dosing pump, had a total cost of $2,400 (1999 NZ $) per installation.

The rainfall-driven system operated by collecting rainfall in a rainfall catchment tray that was designed

proportional to the watershed area. Rainfall into this tray was used to displace the liquid treatment chemical from a storage tank into the stormwater diversion channel prior to entering the sediment basin. The size of the catchment tray was determined based on the size of the catchment draining to the basin, taking into consideration the desired chemical dosage rate obtained from the bench tests. Accumulated rainfall from the catchment tray fills a displacement tank that floats in the chemical storage tank. As the displacement tank fills with rainfall and sinks, liquid chemical is displaced from the chemical storage tank and flows via gravity to the dosing point.

Field trials of the liquid treatment system using alum were conducted at the ALPURT site. The authors report that the system performed “satisfactorily in terms of reduction of suspended solids under a range of rainfall conditions varying from light rain to a very high intensity, short duration storm, where 24mm of rainfall fell over a period of 25 minutes.” Suspended solids removal for the intense storm conditions was 92% with alum treatment. For a similar storm on the same catchment with the same retention pond without alum treatment, suspended solids removal was about 10%.

Field trials at the ALPURT site were also conducted using PAC. In total, 21 systems were used with contributing catchments ranging between 0.5 and 15 hectares (approximately 1 to 37 acres). The overall treatment efficiency of the PAC-treated basins in terms of suspended sediment reduction were reported to be between 90% and 99% for ponds with good physical designs. The authors noted that some systems did not perform as well due to mechanical problems with the system or physical problems such as high inflow energy (which likely caused erosion or sediment resuspension) or poor separation of basin inlets and outlets. The suspended solids removal for all ponds incorporating PAC ranged from 77% to 99.9%, while the removal in a pond not incorporating PAC ranged from 4% to 12%. Influent suspended solids concentrations for the systems incorporating PAC ranged from 128 to 28,845 mg/L while effluent concentrations ranged from 3 to 966 mg/L. In comparison, influent suspended solids concentrations for the untreated ponds were approximately 1,500 mg/L while effluent concentrations were approximately 1,400 mg/L. The authors also noted that dissolved aluminum concentrations in the outflow from the basins treated with PAC, in most cases, were actually less than the inflow concentrations, and were also less than the outflow concentrations from the untreated ponds. Outflow aluminum concentrations in the PAC treated ponds ranged from 0.01 to 0.072 mg/L. The ALPURT trials indicate that a relatively simple PTS using liquid polymers can result in significant reductions in suspended sediment concentrations, even with influent concentrations in excess of 25,000 mg/L. Although some effluent concentrations were as high as several hundred mg/L, the majority were below 100 mg/L. This indicates that a passive liquid polymer system can be used to meet a numeric effluent limitation for turbidity at a capital cost on the order of several thousand dollars per sediment basin. Coupling a system such as this with a gravity sand filter or distributed discharge to a vegetated buffer (as described by Warner and Collins-Camargo, DCN 43071) or dispersion would reduce discharge turbidity levels even further, and for certain storm events would eliminate the discharge altogether.

Field trials of polymer treatment using solid forms of PAM by the Auckland Regional Council were conducted at the ALPURT site as well as a residential project (Greenhithe). Trials at the ALPURT site were conducted by placing the floc-blocks in plastic mesh bags in plywood flumes through which the runoff from the site was directed. Initial trials encountered problems due to the high bedload of granular material, which accumulated against and stuck to the floc-blocks inhibiting solubility of the polymer. The system was reconfigured to incorporate a forebay before the flumes in order to facilitate removal of the bedload fraction. The authors noted that while this system was generally effective at low flow rates, it was difficult to control dosage rates and sediment accumulation in the flumes continued to be a problem. The authors concluded that “Floc Block treatment has a high potential for removal of suspended solids from stormwater with consistent quality, particularly for small catchments; when flow balancing can be achieved prior to treatment.”

Field trials were also conducted at the Greenhithe site, which was a 4-hectare (approximately 10-acre) residential project. As with the ALPURT trial, a flume was constructed and placed in the flow path immediately before the sediment basin. Results of the trials were mixed. The authors noted several problems with the floc-blocks, such as drying and breakdown of the blocks due to prolonged exposure to the air and softening and breakdown during periods of prolonged submergence. Sediment accumulation around the blocks and breakdown continued to be a problem. Incorporating an effective sediment forebay and limiting bedload are suggestions for increasing performance. In addition, the authors recommended soaking the floc-blocks in water to allow hydration before use and periodic spraying with water as ways to limit drying of the floc-blocks. EPA notes that similar problems with floc-blocks have been noted by some construction site field inspectors (see DCN 41109) and by McLaughlin (see DCN 43082). Because of the additional operation and maintenance requirements associated with the use of floc-blocks, a field inspection and maintenance program should be part of proper application of this technology.

Results of the PAC studies at the ALPURT sites have led the Auckland regional council to require chemical treatment for any site that produces more than 1.5 metric tons of (net) sediment as determined by the Universal Soil Loss Equation. Sites that exceed this threshold require chemical treatment in accordance with a site chemical treatment plan. Exceptions include projects of less than one month duration and sites with granular volcanic soils and sand areas. Chemical treatment may also not be required if bench testing indicates that chemical treatment will provide no improvement in sediment removal efficiency (see DCN 41111).

In addition to (or in place of) adding polymers to sediment basins, polymers can be introduced on other areas of the site as a soil stabilization measure or as components of other BMPs. For example, McLaughlin (DCN 41005) evaluated adding polymer to check dams on highway projects. McLaughlin noted significant reductions in turbidity from the use of fiber check dams coupled with PAM application. Significant reductions were even noted when PAM was added to rock check dams. Other research done by McLaughlin with other researchers includes studying the effectiveness of using PAM dosing systems for turbidity reduction in stilling basins (EPA-HQ-OW-2008-0465-0984.4), and using polymer blocks for turbidity control (EPA-HQ-OW-2008-0465-0984.7 and 0984.10). McLaughlin, Hayes et al. also studied modified sediment control practices including polymer dosing at a transportation construction site (EPA-HQ-OW-2008-0465-0984.3)

Various other researchers evaluated PAM as a soil stabilization agent. There are a number of documents in the administrative record for this

rulemaking describing the use of PAM in this manner.

The data from these sources, as well as other data in the record, indicate that various types of PTS that utilize both solid and liquid forms of polymers have been reported to be effective in reducing turbidity levels in discharges from construction and development sites.

EPA also considered the results of a three-year study conducted in Georgia (Warner & Collins-Comargo, DCN 43071) which developed and demonstrated cost-effective erosion prevention and sediment control systems. These controls did not rely on the use of polymer, instead they demonstrate the effectiveness of ponds, passive sand filters and seep berms.

X. Development of Effluent Limitations Guidelines and Standards and Options Selection Rationale

In developing this final rule, EPA considered all the available information, including information, data and analyses conducted in support of the proposed rule, public comments received and additional information and data collected by EPA following proposal which is contained in the record. EPA evaluated a range of options for reducing pollutant discharges associated with construction activity. The options evaluated by EPA are intended to control the discharge of turbidity, sediment and other pollutants in stormwater and other wastewater from C&D sites.

A. Description of the Regulatory Options Considered

1. Options Considered in the Proposal

In developing today's final rule, EPA evaluated several regulatory options. The proposal discussed a wide range of options and presented a detailed analysis for several options. As discussed earlier, Option 1 would have required implementation of erosion and sediment controls and pollution prevention measures for all sites and the installation of a sediment basin with a surface outlet for certain sites and other non-numeric effluent limitations or BMPs; Option 2, would have added to the requirements of Option 1 by establishing a requirement to monitor for a numeric limitation for turbidity (13 NTU) based on the application of ATS at sites of 30 or more acres with soil clay content of 10 percent or more and an R-factor of 50 or larger; Option 3 would have expanded the application of the turbidity limitation based on ATS to all sites which disturb 10 or more acres. The proposal also presented and solicited comment on another option that would require compliance with a higher numeric turbidity effluent limitation (e.g., 50 to 150 NTU, or some other value) based on passive treatment technologies (see 73 FR 72562, 72580-72582, 72610-72611). At proposal, EPA sought additional data on the performance of PTS, and the cost and pollutant loading reductions that would be attainable from such an option.

2. Regulatory Options Considered for the Final Rule and Rationale for Consideration of Revisions to Options in the Proposed Rule

In developing the final rule, EPA considered the wide range of options considered in the proposed rule, and some revisions to those options, based on comments received and additional information obtained by EPA. EPA considered a revision to Option 1 to remove the requirement for a sediment basin in response to concerns raised by commenters about the appropriateness and availability of a basin at all construction sites with 10 or more disturbed acres draining to one location. An example includes areas where excavation is precluded due to the presence of shallow bedrock. In addition to the sediment basin requirements, EPA also considered modifying some of the erosion and sediment control and pollution prevention requirements to make them broadly applicable and compatible with all types of potentially regulated construction activity, and considered deleting certain proposed requirements. These changes to the non-numeric effluent limitations are detailed in Section X.B of this notice.

EPA considered a revision to Option 2 to remove the soil clay content criteria as part of the basis for determining if a site would be subject to the numeric limitation. Numerous commenters expressed concern about difficulties associated with implementation of this soil clay content criterion. Commenters raised questions, for example, about how sites would measure soil content and to what depth would the soil have to be sampled to determine the clay content (e.g., to a depth to which excavation will occur, or only the top several inches). Also, questions were raised as to the number of soil samples that would be required of sites of different size. Also, commenters raised the question of how to account for fill brought onto the site and the variation in soil types present at different depths and at different areas within the site. EPA also considered that adding complexity to the applicability section generally makes it more difficult to comply with, implement and enforce a rule. EPA agrees that the implementation of a soil clay content criterion for determining whether a site would be subject to a numeric limitation would be difficult to implement and therefore considered removing this criterion from Option 2.

EPA similarly considered modifying Option 2 to remove the RUSLE R-factor criterion as part of the basis for determining if a site would be subject to the numeric limitation. EPA received numerous comments about the potential practical difficulties associated with this criterion. Particularly, R-factor data is not readily available for all areas of the country, including the entire state of Alaska. Also, in certain areas of the country, the annual R-factor may be low, but soil erosion rates may still be very high during certain time periods (such as during spring thawing). Therefore, EPA determined that an annual R-factor criterion, as proposed, would not be easily implementable, nor necessarily target those sites with greater potential for soil erosion.

EPA also considered revising Options 2 and 3 so that the monitoring requirements and turbidity limitation would not apply to interstate natural gas pipeline construction activity (see discussion in Section VI).

EPA also considered changing Option 2 so that the applicability of the turbidity limitation would be a function of disturbed area of the site, as opposed to the total size of the site. In addition, EPA considered revising the non-numeric effluent limitations of Option 2 (as well as Option 3) to be consistent with the Option 1 requirements discussed above.

EPA also considered the option discussed in the proposal (Option 4) that would establish a numeric limitation for turbidity based on the application of PTS for the final rule. This option would require all construction sites to implement the non-numeric effluent limitations described for Option 1, as well as requiring sites equal to or greater than a specified number of acres disturbed at one time to meet a numeric limitation to control turbidity and other pollutants in stormwater discharges from C&D sites. EPA considered thresholds of 1, 5 and 10 acres disturbed at one time for this option. The technology basis for Option 4 consists of a suite of passive treatment technologies and erosion and sediment controls that are currently used at construction sites across the United States and abroad, as well as in other industries, such as drinking water treatment and mining. Examples of passive treatment technologies include sediment basins, sediment traps and

other impoundments (with and without polymer or flocculant dosing), polymer addition to fiber check dams, sand filtration, and dispersion of stormwater to vegetated areas. PTS can substantially reduce the amount of turbidity, sediment and other pollutants discharged from construction sites. See Section IX for additional discussion of passive treatment approaches.

B. Non-Numeric Effluent Limitations Included in All Regulatory Options

Today's final rule, as well as the other options EPA considered, includes a suite of non-numeric effluent limitations that apply to all permitted C&D sites. This suite of non-numeric effluent limitations makes up Option 1 and is also a component of Options 2, 3 and 4. These non-numeric effluent limitations are structured to require permittees to first prevent the discharges of sediment and other pollutants through the use of effective planning and erosion control measures; and second, to control discharges that do occur through the use of effective sediment control measures. Permittees are also required to implement a range of pollution prevention measures to limit or prevent discharges of pollutants including those from dry weather discharges.

The non-numeric effluent limitations that are included in all options are designed to prevent the mobilization and discharge of sediment and sediment-bound pollutants, such as metals and nutrients, and to prevent or minimize exposure of stormwater to construction materials, debris and other sources of pollutants on construction sites. In addition, these non-numeric effluent limitations limit the generation of dissolved pollutants. Soil on construction sites can contain a variety of pollutants such as nutrients, organics, pesticides, herbicides and metals. These pollutants may be present naturally in the soil, such as arsenic or selenium, or they may have been contributed by previous activities on the site such as agriculture or industrial activities. These pollutants, once mobilized by rainfall and stormwater, can detach from the soil particles and become dissolved pollutants. Once dissolved, these pollutants would not be removed by down-slope sediment controls. Source control through minimization of soil erosion is therefore the most effective way of controlling the discharge of these pollutants. Therefore, the non-numeric effluent limitations are important components of the final rule not only for the purposes of limiting sediment generation and discharge, but also to minimize the discharge of dissolved pollutants.

The non-numeric effluent limitations in the final rule apply to all permitted C&D sites including the sites that are subject to the numeric effluent limitation and monitoring requirements at 40 CFR 450.22. (See Section X.G.) EPA has the authority under the CWA to establish non-numeric effluent limitations as supplemental to a numeric effluent limitation or in place of a numeric effluent limitation. See

Citizens Coal Council

v.

EPA,

447 F.3d 879, 896 (6th Cir. 2006). The non-numeric effluent limitations in this rule are necessary for those sites that are also subject to the numeric effluent limitation for turbidity because the non-numeric effluent limitations may address different pollutants or the same pollutants differently, the numeric effluent limitation is not applicable on days when total precipitation on that day is greater than the local 2-year, 24-hour storm event (See Section XIX.A), and the fact that sites may fluctuate above and below ten acres of disturbed land. Thus there will be times when sites are discharging pollutants in excess of the numeric effluent limitation and the non-numeric effluent limitations will be the only applicable effluent limitation and are thus essential to the control of discharges from the site. Also, some of the non-numeric effluent limitations are addressing discharges unrelated to the discharge of turbidity, for example, 40 CFR 450.21(e)(1) which prohibits the discharge of “wastewater from washout of concrete, unless managed by an appropriate control” addresses pollutants such as pH and can occur during precipitation related events or dry weather discharges. The structure of the final rule, including the requirement that the non-numeric effluent limitations apply to all sites, was supported by state permitting authorities and is similar to the structure of the newly issued California CGP (see DCN 42104).

The final rule contains non-numeric effluent limitations that require the permittee to minimize the discharge of pollutants. Under the regulatory structure of the final rule the permitee can minimize the discharge of pollutants from construction sites by utilizing non-numeric effluent limitations or BMPs such as the erosion and sediment controls listed below at (i) through (vii) and at 40 CFR 450.21(a)(1) through (7). The erosion and sediment controls at (i) through (vii) below are what EPA has determined are the required non-numeric effluent limitations that are necessary for owners or operators of construction sites to utilize in order to minimize the discharge of pollutants from the site. This is true for the other non-numeric effluent limitations at 40 CFR 450.21 as they are what EPA has determined are the required controls necessary to minimize, control or prohibit discharges of pollutants from construction sites. The permitting authority may determine that additional non-numeric effluent limitations or specific BMPs are necessary in order to minimize the discharge of pollutants and EPA has structured 40 CFR 450.21 to allow the permitting authority that discretion. Due to geographic differences or other variable factors a permitting authority may choose to require additional or more stringent non-numeric effluent limitations in its individual or general NPDES permits for discharges associated with construction activity. For example, the permitting authority may determine that it is necessary for permitees to initiate soil stabilization measures when construction activity has permanently or temporarily ceased and will not resume for a period exceeding 7 calendar days, as opposed to 14 calendar days at X.B.1.b below or that additional erosion and sediment controls are necessary. EPA purposefully drafted the non-numeric effluent limitations to allow for flexibility in how the permitting authority implements the requirement in NPDES permits. For example, in the erosion and sediment control section below at section X.B.1.a.iv EPA simply required that permitees “minimize the disturbance of steep slopes” leaving it up to the permitting authority to determine the specific requirements applicable to owners or operators of C&D sites to minimize disturbance of steep slopes in order to minimize the discharge of pollutants from the site. This flexibility built into the final rule will also benefit permittees by allowing the owners or operators of construction sites discretion to choose BMPs that will minimize the discharge of pollutants based on the unique nature of the particular site. For example, at 40 CFR 450.21(a)(5), the final rule states that construction sites must design, install and maintain controls to “minimize sediment discharges from the site.” Absent specific requirements from the permitting authority the final rule gives the permittee discretion to choose what practices and controls to use to minimize the discharge of sediment from the site based on the site specific nature of the construction activity.

The non-numeric effluent limitations are required for all sites, but there are

site-specific considerations that may make one or more of the provisions infeasible on a particular site. EPA has specifically qualified some of the requirements to state that the requirement must be implemented unless infeasible. By infeasible, EPA means that there is a site-specific constraint that makes it technically infeasible to implement the requirement, or that implementing the requirement would be cost-prohibitive. The burden is on the permittee to demonstrate to the permitting authority that the requirement is infeasible.

With respect to the soil stabilization language at § 450.21(b), EPA has qualified the soil stabilization requirements such that vegetative stabilization may be delayed in arid or semi-arid areas, or if an area is experiencing a drought such that vegetative stabilization practices cannot be initiated. In such cases, the permittee should consider non-vegetative stabilization practices. In addition, EPA would generally not expect permitting authorities to require vegetative stabilization in areas that are excessively rocky or infertile, that have non-erodible soils (such as sands), certain coastal areas, or during periods when snow or ice are covering the ground and generally in areas where vegetative stabilization would not be appropriate. Permitting authorities should incorporate this requirement into permits with consideration of appropriate stabilization measures for various areas within their jurisdiction.

EPA made several revisions to the non-numeric effluent limitation since proposal. Some of these revisions were made in response to comments, while others were made as a result of EPA re-evaluating the feasibility and appropriateness of some of the proposed requirements. Section X.B.1 describes the non-numeric effluent limitations contained in the final rule while Section X.B.2 describes how the non-numeric effluent limitations in final rule differ from those in the proposal.

1. Non-Numeric Effluent Limitations Contained in the Final Rule

The non-numeric effluent limitations contained in the final rule are as follows:

a. Erosion and Sediment Controls

Permittees are required to design, install and maintain effective erosion controls and sediment controls to minimize the discharge of pollutants. At a minimum, such controls must be designed, installed and maintained to:

i. Control stormwater volume and velocity within the site to minimize soil erosion;

ii. Control stormwater discharges, including both peak flowrates and total stormwater volume, to minimize erosion at outlets and to minimize downstream channel and streambank erosion;

iii. Minimize the amount of soil exposed during construction activity;

iv. Minimize the disturbance of steep slopes;

v. Minimize sediment discharges from the site. The design, installation and maintenance of erosion and sediment controls must address factors such as the amount, frequency, intensity and duration of precipitation, the nature of resulting stormwater runoff, and soil characteristics, including the range of soil particle sizes expected to be present on the site;

vi. Provide and maintain natural buffers around surface waters, direct stormwater to vegetated areas to increase sediment removal and maximize stormwater infiltration, unless infeasible; and

vii. Minimize soil compaction and, unless infeasible, preserve topsoil.

b. Soil Stabilization Requirements

Permittees are required to, at a minimum, initiate soil stabilization measures immediately whenever any clearing, grading, excavating or other earth disturbing activities have permanently ceased on any portion of the site, or temporarily ceased on any portion of the site and will not resume for a period exceeding 14 calendar days. Stabilization must be completed within a period of time determined by the permitting authority. In arid, semiarid, and drought-stricken areas where initiating vegetative stabilization measures immediately is infeasible, vegetative stabilization measures must be initiated as soon as practicable.

c. Dewatering Requirements

Permittees are required to minimize the discharge of pollutants from dewatering trenches and excavations. Discharges are prohibited unless managed by appropriate controls.

d. Pollution Prevention Measures

Permittees are required to design, install, implement, and maintain effective pollution prevention measures to minimize the discharge of pollutants. At a minimum, such measures must be designed, installed, implemented and maintained to:

i. Minimize the discharge of pollutants from equipment and vehicle washing, wheel wash water, and other wash waters. Wash waters must be treated in a sediment basin or alternative control that provides equivalent or better treatment prior to discharge;

ii. Minimize the exposure of building materials, building products, construction wastes, trash, landscape materials, fertilizers, pesticides, herbicides, detergents, sanitary waste and other materials present on the site to precipitation and to stormwater; and

iii. Minimize the discharge of pollutants from spills and leaks and implement chemical spill and leak prevention and response procedures.

e. Prohibited Discharges

The following discharges from C&D sites are prohibited:

i. Wastewater from washout of concrete, unless managed by an appropriate control;

ii. Wastewater from washout and cleanout of stucco, paint, form release oils, curing compounds and other construct

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