ENVIRONMENTAL PROTECTION AGENCY

	40 CFR Part 450

	[EPA-HQ-OW-2008-0465; FRL-XXXX-X]

	RIN 2040-AE91

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

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

SUMMARY: The Environmental Protection Agency is proposing a regulation
that would strengthen the existing regulatory program for discharges
from construction sites by establishing technology-based Effluent
Limitations Guidelines and New Source Performance Standards for the
Construction and Development (C&D) point source category. This proposal,
if implemented, would significantly reduce the amount of sediment and
other pollutants discharged from construction sites. EPA estimates that
this proposed rule would cost up to $1.9 billion dollars per year and
reduce discharges of sediment by up to 27 billion pounds annually. This
proposed rule requests comment and information on the proposed
regulation and a variation of the proposed option with a different
numeric limit, as well as specific aspects of the proposal such as
technologies, costs, and affordability.

DATES: Comments must be received on or before [INSERT DATE 90 DAYS AFTER
DATE OF PUBLICATION IN THE FEDERAL REGISTER].

ADDRESSES: Submit your comments, identified by Docket ID No.
EPA-HQ-OW-2008-0465, by one of the following methods:

  HYPERLINK "http://www.regulations.gov"  www.regulations.gov : This is
EPA’s preferred approach, although you may use the alternatives
presented below. Follow the on-line instructions for submitting
comments.

	(	Email<EMAIL_ADDRESS>
Mail: USEPA Docket Center, Environmental Protection Agency, Docket
Number EPA-HQ-OW-2008-0465, Mailcode 2822T, 1200 Pennsylvania Ave., NW,
Washington, DC 20460.

Hand Delivery: USEPA Docket Center, Public Reading Room, 1301
Constitution Ave., NW, Room 3334, EPA West Building, Washington DC
20004. Such deliveries are only accepted during the Docket’s normal
hours of operation, and special arrangements should be made for
deliveries of boxed information.

Instructions: Direct your comments to Docket ID No. EPA-HQ-OW-2008-0465.
EPA's policy is that all comments received will be included in the
public docket without change and may be made available online at
HYPERLINK "http://www.regulations.gov"  www.regulations.gov , including
any personal information provided, unless the comment includes
information claimed to be Confidential Business Information (CBI) or
other information whose disclosure is restricted by statute. Do not
submit information that you consider to be CBI or otherwise protected
through www.regulations.gov or e-mail. The   HYPERLINK
"http://www.regulations.gov"  www.regulations.gov  website is an
“anonymous access” system, which means EPA will not know your
identity or contact information unless you provide it in the body of
your comment. If you send an e-mail comment directly to EPA without
going through www.regulations.gov your e-mail address will be
automatically captured and included as part of the comment that is
placed in the public docket and made available on the Internet. If you
submit an electronic comment, EPA recommends that you include your name
and other contact information in the body of your comment and with any
disk or CD-ROM you submit. If EPA cannot read your comment due to
technical difficulties and cannot contact you for clarification, EPA may
not be able to consider your comment. Electronic files should avoid the
use of special characters, any form of encryption, and be free of any
defects or viruses. For additional information about EPA’s public
docket visit the EPA Docket Center homepage at
http://www.epa.gov/epahome/dockets.htm.

Docket: All documents in the docket are listed in the   HYPERLINK
"http://www.regulations.gov"  www.regulations.gov  index. 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, will be publicly
available only in hard copy. Publicly available docket materials are
available either electronically in   HYPERLINK
"http://www.regulations.gov"  www.regulations.gov  or in hard copy at
the USEPA Docket Center, Public Reading Room, Room 3334, EPA West
Building, 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<PHONE_NUMBER>, and the telephone number for the EPA Docket
Center is<PHONE_NUMBER>. Please note that several of the support
documents are available at no charge on EPA's website; see "Supporting
Documentation" below.

FOR FURTHER INFORMATION CONTACT: For technical information concerning
today's proposed rule, contact Mr. Jesse W. Pritts at<PHONE_NUMBER>
(pritts.jesse@epa.gov). For economic information contact Mr. Todd Doley
at<PHONE_NUMBER> (  HYPERLINK<EMAIL_ADDRESS><EMAIL_ADDRESS>).

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 proposed rule
and the definition of "construction activity" and "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 entity, consult one of the
persons listed for technical information in the preceding "FOR FURTHER
INFORMATION CONTACT" section.

Supporting Documentation

	Several key documents support the proposed regulations:

1. "Development Document for Proposed Effluent Guidelines and Standards
for the Construction and Development Category," EPA-821-R-08-007.
("Development Document") This document presents EPA's methodology and
technical conclusions concerning the C&D category.

2. "Economic Analysis for Proposed Effluent Guidelines and Standards for
the Construction and Development Category," EPA-821-R-08-008. ("Economic
Analysis") This document presents the methodology employed to assess
economic impacts of the proposed rule and the results of the analysis.

3. "Environmental Impact and Benefits Assessment for Proposed Effluent
Guidelines and Standards for the Construction and Development Category,"
EPA-821-R-08-009 ("Environmental Assessment"). This document presents
the methodology to assess environmental impacts and benefits of the
proposed rule and the results of the analysis.

	Major supporting documents are available in hard copy from the National
Service Center for Environmental Publications (NSCEP), U.S. EPA/NSCEP,
P.O. Box 42419, Cincinnati, Ohio, USA 45242-2419, telephone
800-490-9198, http://www.epa.gov/ncepihom/. You can obtain electronic
copies of this preamble and proposed rule as well as the technical and
economic support documents for today's proposal at EPA's website 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 proposed
regulations; the legal authority of this proposed rule; a summary of the
proposal; background information; and the technical and economic
methodologies used by the Agency to develop this proposed regulation.
While EPA solicits comments on this entire proposal, EPA emphasizes
specific areas of interest where we would particularly like comments,
information and data.

	Table of Contents

I. Legal Authority

II. Purpose & Summary of the Proposed Rule

III. Background on Existing Regulatory Program

A. Clean Water Act

B. NPDES Stormwater Permit Program

C. Other State and Local Stormwater Requirements

D. Technology-Based Effluent Limitations Guidelines and Standards

IV. Scope of the Proposal

V. Overview of the Construction and Development Industry and
Construction Activities

VI. Summary of Data Collection Activities

A. State Data

B. National Land Cover Dataset (NLCD)

C. Enhanced River Reach File 1.2 (ERF1)

D. NPDES Notice of Intent (NOI) Data

E. Soils Data

F. NOAA Rainfall Data

G. Parameter Elevation Regressions on Independent Slopes Model (PRISM)

H. Revised Universal Soil Loss Equation (RUSLE) R Factors

I. Economic Data

VII. Characteristics of Discharges from Construction Activity

VIII. Description of Available Technologies

A. Introduction

B. Erosion Control Measures

C. Sediment Control Measures

D. Other Construction and Development Site Management Practices

IX. Development of Effluent Limitations Guidelines and Standards

A. Description of the Regulatory Options Considered

B. Effluent Limitations Included in All Regulatory Options

C. Options for BPT, BCT, BAT and NSPS

D. Option Selection Rationale for BPT

E. Option Selection Rationale for BAT and NSPS

F. Option Selection Rationale for BCT

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

XI. Economic Impact and Social Cost Analysis

A. Introduction

B. Description of Economic Activity

C. Method for Estimating Economic Impacts

D. Results

XII. Cost-Effectiveness Analysis

XIII. Non Water-Quality Environmental Impacts

A. Air Pollution

B. Solid Waste Generation

C. Energy Usage

XIV. Environmental Assessment

A. Introduction

B. Methodology for Estimating Environmental Impacts and Pollutant
Reductions

XV. Benefit Analysis

A. Benefits Categories Estimated

B. Quantification of Benefits

XVI. Monetized Benefit-Cost Comparison

XVII. Approach to Determining Long-Term Averages, Variability Factors,
and Effluent Limitations and Standards

A. Definitions

B. Data Selection

C. Statistical Percentile Basis for Limitations

D. Daily Maximum Limitations

E. Engineering Review of Limitations

F. Monthly Average Limitations

XVIII. Regulatory Implementation

A. Relationship of Effluent Guidelines to NPDES Permits and ELG
Compliance Dates

B. Upset and Bypass Provisions

C. Variances and Waivers

D. Other Clean Water Act Requirements

XIX. 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.

XX. Solicitation of Data and Comments

A. General Solicitation of Comment

B. Specific Solicitation of Comments and Data

C. Guidelines for Submission of Analytical Data

I. Legal Authority  TC \l1 "I. Legal Authority

	EPA is proposing this regulation under the authorities of sections 301,
304, 306, 308, 402, 501 and 510 of the Clean Water Act (CWA), 33 U.S.C.
1311, 1314, 1316, 1318, 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 Proposed Rule  TC \l1 "II. Purpose &
Summary of Proposed Rule

	Despite substantial improvements in the nation’s water quality since
the inception of the Clean Water Act, 45 percent of assessed river and
stream miles, 47 percent of assessed lake acres, and 32 percent of
assessed square miles of estuaries show impairments from a wide range of
sources. Improper control of stormwater discharges from construction
activity is among the many contributors of sediment which is one of the
principle remaining water quality problems throughout the United States.
Sediment is the primary pollutant that causes water quality impairment
for streams and rivers. It is also one of the leading causes of lake and
reservoir water quality impairment and wetland degradation. The sediment
entrained in stormwater discharges from construction activity
contributes to harm in aquatic ecosystems, increases drinking water
treatment costs, and degrades recreational uses of impacted waters.
Sediment can also accumulate in rivers, lakes, and reservoirs, leading
to the need for dredging or other mitigation.

	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 generated during construction
activities can cause an array of physical, chemical and biological
impacts. Sediment discharges can cause an array of physical and
biological impacts on receiving waters. In addition to sediment, a
number of other pollutants (e.g., metals 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 (C&D) 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 from construction activity
can elevate these loads to levels above those in undisturbed watersheds.

	Existing national stormwater regulations at 40 CFR 122.26 require
permittees to implement control measures to manage discharges associated
with construction activity. Today’s proposal establishes a
technology-based “floor” or minimum requirements on a national
basis. This rule would constitute the nationally applicable,
technology-based effluent limitations guidelines (ELGs) and new source
performance standards (NSPS) (referred to collectively in this notice as
“ELGs” or “effluent limitations guidelines,” unless specifically
referencing NSPS), applicable to all dischargers currently required to
obtain a National Pollutant Discharge Elimination System (NPDES) permit
pursuant to 40 CFR 122.26(b)(14)(x) and 122.26(b)(15). The proposed ELGs
would require stormwater discharges from certain C&D sites to meet
effluent limitations designed to reduce the amount of sediment,
turbidity, TSS and other pollutants in stormwater discharges from the
site. EPA acknowledges that many state and local governments have
existing effluent limitations and standards for controlling stormwater
and wastewater discharges from construction sites. Today's proposed ELGs
are intended to work in concert with these existing state and local
programs. Today’s proposed regulation would establish a numeric
effluent limit for turbidity in discharges from some C&D sites. EPA
envisions these turbidity effluent limits as requiring an additional
layer of management practices above what most state and local programs
are currently requiring. Permitting authorities would be required to
incorporate these turbidity limitations into their permits and
permittees would be required to implement control measures to meet a
numeric turbidity limit in discharges of stormwater from their C&D
sites. EPA is not dictating that a specific technology be used to meet
the numeric limit, but is specifying the maximum turbidity level that
can be present in discharges from C&D sites. Permittees have the
flexibility to select management practices that are best suited to
site-specific conditions present on each individual C&D site.

III. Background on Existing Regulatory Program  TC \l1 "III. Background

A. Clean Water Act  TC \l2 "A. Clean Water Act

	Congress passed the Federal Water Pollution Control Act of 1972 (Public
Law 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). 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 National Pollutant Discharge Elimination System (NPDES)
permit for the discharge of any pollutant from a point source
notwithstanding Section 301(a). 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 of 1987 (Public Law 100-4, February 4, 1987)
amended the CWA, adding CWA section 402(p) to require implementation of
a comprehensive program for addressing stormwater discharges. 33 U.S.C.
1342(p). The NPDES program was expanded by requiring EPA or NPDES
authorized states or tribes to issue NPDES permits for stormwater
discharges listed under Section 402(p)(2), which include municipal and
industrial stormwater discharges. Industrial stormwater dischargers,
municipal separate storm sewer systems and other stormwater dischargers
designated by EPA must obtain NPDES permits pursuant to CWA section
402(p). Stormwater discharges associated with industrial activity must
meet all applicable provisions of CWA sections 301 and 402, including
meeting technology-based effluent limitations.

B. NPDES Stormwater Permit Program  TC \l2 "B. NPDES Storm Water Permit
Program

	EPA's Phase I stormwater regulations promulgated in 1990 identified
stormwater discharges associated with construction activity as one of
several types of industrial activity requiring an NPDES permit.
Dischargers must apply for and obtain authorization to discharge (or
“permit coverage”) (40 CFR 122.26(b)(14)(x) and (c)(1)). As
described in the Phase I regulations, a permit is required for
discharges associated with construction activity, including clearing,
grading, and excavation, if the construction activity:

	•	will disturb five acres or greater; or

•	will disturb less than five acres but is part of a larger common
plan of development or sale whose total land disturbing activities total
five acres or greater;.

EPA defines these as “large” construction sites as stormwater
discharges associated with industrial activity. (See 40 CFR
122.26(b)(14)).

	The Phase II stormwater regulations, promulgated in 1999, extended
permit coverage to construction activity that results in land
disturbance of one acre or greater (40 CFR 122.26(b)(15)), including
sites less than one acre that are part of a larger common plan of
development or sale whose total land disturbing activities total more
than an acre. EPA’s NPDES regulations define these sites, i.e., sites
disturbing between one and five acres, as “small” construction
sites.

	In addition to requiring permits for discharges associated with
construction activity, the NPDES regulations require permits for certain
municipal separate storm sewer systems (MS4s). Operators of these MS4s,
typically local governments, must develop and implement a stormwater
management program, including a requirement to address stormwater
discharges from construction activity. More details on the requirements
of MS4 programs are described in section III.B.2.

1. Stormwater Permits for Construction Activity  TC \l3 "1. Storm Water
Permits for Construction: General and Individual

	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
construction sites follows.

	a. General NPDES Permits  TC \l4 "a. General Permits

	The vast majority of discharges from 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 through public
notice. Typically, to obtain authorization to discharge under a
construction general permit, a discharger (typically, a developer,
builder, or contractor) submits to the permitting authority a Notice of
Intent (NOI) to be covered under the general permit. 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 from 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  TC \l4 "b. EPA Construction General
Permit

	Since 1992, EPA has issued a series of “national” Construction
General Permits that cover areas where EPA is the NPDES permitting
authority. At present, EPA is the permitting authority in five states
(Alaska, 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 issued a final
"national" CGP on July 1, 2003 (63 FR 7898), modified on November 22,
2004 (changes effective January 21, 2005). EPA’s current CGP became
effective on June 30, 2008 (see 74 FR 40338). Following promulgation of
the effluent limitations guidelines, EPA will issue a revised CGP
incorporating the new ELGs.

	The key component of EPA’s CGP is the requirement to minimize
discharges of pollutants in stormwater discharges using control measures
that reflect best engineering practices. Dischargers must minimize their
discharge of pollutants in stormwater using appropriate erosion and
sediment control “best management practices” (BMPs) 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 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 website 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 runoff 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.

	To discontinue permit coverage, a discharger must either complete final
stabilization of the site, transfer responsibility to another party
(e.g., a developer transferring land to a home builder), or for a
residential property, complete temporary stabilization and transfer the
property to the homeowner. The permittee submits a Notice of Termination
(NOT) Form to the permitting authority upon satisfying the appropriate
permit termination conditions described in the CGP.

	c. State Construction General Permits  TC \l4 "c. State Construction
General Permits

	Whether EPA, a state or a tribe issues the general permit, the CWA
requires that NPDES permits must include technology-based effluent
limitations. 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 from 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
constructions sites within their jurisdiction (e.g., soil types,
topographic or climatic characteristics, or other relevant factors). For
example, Washington, Oregon and Vermont’s CGPs include turbidity
action levels and discharge monitoring requirements for C&D sites
applicable to all or a subset of construction sites.

	d. Individual NPDES Permits  TC \l4 "d. Individual 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 from construction activity.

	a. NPDES Requirements  TC \l4 "a. NPDES Requirements

	A municipal separate storm sewer system (MS4) is a conveyance or system
of conveyances 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). A municipal separate
storm sewer system is (MS4) is all large, medium, and small municipal
storm sewers or those designated as such under the 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. The Phase II regulations also provide
permitting authorities with the authority to designate any additional
MS4s located outside of urbanized areas for permit coverage where the
permitting authority determines that storm water controls are needed for
the discharge based on wasteload allocations that are part of total
maximum daily loads that address pollutants of concern or the permitting
authority or the EPA Regional Administrator determines 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)(i)(C) and (D). 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.

	Both the Phase I and II rules require regulated municipalities to
develop comprehensive stormwater management programs which include,
among other elements, the regulation 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
runoff from construction sites, 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 runoff from 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 regulating stormwater discharges from 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 many 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 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  TC \l4 "b. EPA Guidance to
Municipalities

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

•	National Menu of BMPs (  HYPERLINK
http://www.epa.gov/npdes/menuofbmps/menu.htm
http://www.epa.gov/npdes/menuofbmps/menu.htm ). 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 (  HYPERLINK
http://www.epa.gov/npdes/stormwater/measurablegoals
http://www.epa.gov/npdes/storm water/measurablegoals ). This document
assists small MS4s in defining performance targets and includes examples
of goals for practices to control stormwater discharges from
construction activities.

	•	Storm Water Phase II Compliance Assistance Guide (EPA 833-R-00-002,
March 2000,   HYPERLINK
http://cfpub.epa.gov/npdes/stormwater/smms4.cfm?program_id=6
http://cfpub.epa.gov/npdes/stormwater/smms4.cfm?program_id=6 ). 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  TC \l2 "C. Other State
and Local Storm Water 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. An EPA analysis 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  TC
\l2 "D. Effluent Guidelines and Standards Program

	Effluent limitation guidelines and new source performance standards are
technology-based effluent limitations required by CWA sections 301 and
306 for categories or subcategories of point source dischargers. These
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 NSPS 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)  TC \l3
"1. Best Practicable Control Technology Currently Available (BPT)

	In establishing effluent guidelines for a point source category, the
CWA requires EPA to specify BPT effluent limits 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
cost of achieving effluent reductions in relation to the effluent
reduction benefits. The Agency also considers the age of the equipment
and facilities, the processes employed and any required process changes,
engineering aspects of the control technologies, non-water quality
environmental impacts (including energy requirements), and such other
factors as the 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 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
unless the required additional reductions are "wholly out of proportion
to the costs of achieving such marginal level of reduction." 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 expected discharges after application of BPT, the
general environmental effects of pollutants, and the cost and economic
impacts of the required level of pollution control. In past effluent
limitation guidelines, BPT cost-reasonableness comparisons ranged from
$0.26 to $41.44 per pound removed in year 2008 dollars. This range does
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 $2.50 per pound (in 2001 dollars). In developing guidelines, the
Act does not require consideration of water quality problems
attributable to particular point sources, nor does it require
consideration of water quality improvements in particular bodies of
water. See American Frozen Foods Inst. v. Train, 539 F.2d 107, 117 (D.C.
Cir.1976); Weyerhaeuser Company v. Costle, 590 F. 2d 1011, 1036, 1041-44
(D.C. Cir. 1978).

2. Best Available Technology Economically Achievable (BAT)  TC \l3 "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 direct discharging facilities in the subcategory or
category. CWA section 304(b)(2)(A). The factors considered in assessing
BAT include the cost of achieving BAT effluent reductions, the age of
equipment and facilities involved, the processes employed, engineering
aspects of the control technology, potential process changes, non-water
quality environmental impacts (including energy requirements), and such
factors as the Administrator deems appropriate. CWA section 304(b)(2).
The Agency retains considerable discretion in assigning the weight to be
accorded to these factors. Natural Resources Defense Council v. EPA, 863
F.2d 1420, 1426 (9th Cir1988). An additional statutory factor considered
in setting BAT is "economic achievability." EPA may determine the
economic achievability of an option on the basis of the total cost to
the subcategory and the overall effect of the rule on the industry's
financial health. The Agency may base BAT limitations upon effluent
reductions attainable through changes in a facility's processes and
operations. See Texas Oil & Gas Ass’n v. EPA, 161 F.3d 923, 928 (5th
Cir.1998) (citing “process changes” as one factor EPA must consider
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).

3. Best Conventional Pollutant Control Technology (BCT)  TC \l3 "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).

	Section 304(a)(4) designates the following as conventional pollutants:
biochemical oxygen demand (BOD5), total suspended solids (TSS), fecal
coliform, pH, and any additional pollutants defined by the Administrator
as conventional. 40 CFR 401.16. The Administrator designated oil and
grease as an additional conventional pollutant on July 30, 1979 (44 FR
44501).

4. New Source Performance Standards (NSPS)  TC \l3 "4. New Source
Performance Standards (NSPS)

	NSPS reflect effluent reductions that are achievable based on the best
available demonstrated control technology. 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 for all pollutants (i.e., conventional,
nonconventional, and priority pollutants). In establishing NSPS, CWA
section 306 directs EPA to take into consideration the cost of achieving
the effluent reduction and any non-water quality environmental impacts
and energy requirements.

5. Pretreatment Standards  TC \l3 "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 indicating that construction sites typically
discharge directly to POTWs. Therefore, EPA is not proposing 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 POTWs. 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 regulatory options proposed 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
limits. The CWA does not mandate the use of numeric limitations only 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).

	Federal courts have recognized the CWA does not mandate that EPA use
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 CWA sections 402(a), 304(b) and 502(11) to incorporate
non-numeric effluent limitations for conventional and non-conventional
pollutants. The Sixth Circuit further held as reasonable the Agency
position that CWA sections 304(b), 304(e) and 502(11), read together,
allow non-numeric effluent limitations to supplement CWA section 304(b),
or can stand as effluent limitations themselves. 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.”); Natural Res. Def. Council, Inc. v. Costle,
568 F.2d 1369 (D.C.Cir.1977) (in determining EPA did not have the
authority to exclude particular point source from the NPDES program, the
Court held “when numerical effluent limitations are infeasible, EPA
may issue permits with conditions designed to reduce the level of
effluent discharges to acceptable levels. This may well mean opting for
a gross reduction in pollutant discharge rather than fine-tuning
suggested by numerical limitations.”)

	EPA’s NPDES regulations reflect EPA’s long standing interpretation,
as supported by federal court decisions, that the CWA allows for
non-numeric effluent limitations. 40 CFR 122.44(k).

7. 2002 Construction and Development Proposal and Subsequent Litigation

EPA identified the C&D industry 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 53,008 and 53,011 (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 NSPS. (67 FR 42644; June 24, 2002).

On April 26, 2004, EPA determined that national effluent limitations
guidelines would not be the most effective way to control discharges
from construction sites, and instead chose to rely on the range of
existing programs, regulations, and initiatives that already existed at
the federal, state and local level. (69 FR 22472; April 26, 2004).

On October 6, 2004, the Natural Resources Defense Council, Inc. and
additional plaintiffs filed a complaint in district court alleging that
EPA’s decision not to promulgate ELGs and NSPSs for the C&D industry
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. The district court enjoined EPA to propose ELGs and NSPSs for the
C&D industry by December 1, 2008 and to promulgate ELGs and NSPSs as
soon as practicable, but in no event later than December 1, 2009. On
appeal, the Ninth Circuit in NRDC v. EPA, 2008 WL 4253944 (9th Cir.2008)
affirmed the district court’s decision holding that “…the CWA is
unambiguous that the EPA must promulgate ELGs and NSPSs for the
point-source categories listed in a plan pursuant to [section]
304(m)..” The deadline to seek re-hearing in the Ninth Circuit was
November 3, 2008. The Agency requested a 30-day extension of the
re-hearing deadline, which was granted, thus the new deadline for EPA to
seek re-hearing is December 3, 2008.

IV. Scope of the Proposal  TC \l1 "IV. Scope of Proposal

	EPA is proposing a regulation that would strengthen the existing
controls on discharges from construction activity by establishing
technology-based effluent limitations guidelines and new source
performance standards for the C&D point source category. This proposal,
if implemented, would significantly reduce the amount of sediment, TSS,
turbidity and other pollutants discharged from construction sites due to
construction activities. EPA estimates that today’s proposed rule
would cost up to $1.9 billion dollars per year and reduce discharges of
sediment by up to 27 billion pounds annually. These estimates do not
include costs for Alaska, Hawaii and the U.S. territories because EPA
lacked data on the amount of construction occurring in these areas.
However, EPA does expect that some construction sites in these areas
would incur compliance costs as a result of today’s proposal. EPA
solicits data that can be used to estimate the number of acres of
construction activity that occurs annually in these areas.

	The proposed rule would establish 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 and control the discharge of pollutants
in stormwater and other wastewater from construction sites. The rule
would specify particular minimum BMPs to meet the effluent limitations
requiring effective erosion control and pollution prevention.

	In addition, reflecting current requirements in the EPA CGP, sites
disturbing 10 or more acres at one time would be required to install a
sediment basin to contain and settle sediment from stormwater runoff.
The proposed rule would require minimum standards of design for sediment
basins; however, alternatives that control sediment discharges in a
manner equivalent to sediment basins would be authorized where approved
by the permitting authority.

	Finally, reflecting the BAT and NSPS levels of control, certain large
sites located in areas of high rainfall energy and with soils with
significant clay content, discharges of stormwater from the site would
be required to meet a numeric effluent limit on the allowable level of
turbidity. The numeric turbidity limit is 13 nephelometric turbidity
units (NTUs). The turbidity limit is intended to remove fine-grained and
slowly-settling or non-settleable particles contained in stormwater.
Particles such as clays and fine silts contained in stormwater
discharges from C&D sites typically cannot be effectively removed by
conventional stormwater BMPs (such as sediment basins and sediment
traps) that rely solely on settling unless sufficient detention time or
additives are implemented. The technology basis for the turbidity limit
is active treatment systems (ATS), which consists of polymer-assisted
clarification followed by filtration.

	In addition to this proposed option, EPA is specifically soliciting
comment on setting a turbidity limit at 50 NTUs based on passive
treatment, instead of ATS. See section IX.A.5.a of today’s proposal
for additional discussion of this alternative approach.

EPA considered several other regulatory approaches while developing this
proposed rule, such as specifying certain design criteria for sediment
basins, or using different size, rainfall, or soil type thresholds for
determining which sites would be required to comply with a turbidity
limit on the sediment basin effluent. Details of the proposed rule and
alternative approaches considered are described in this notice, the
Development Document, Economic Analysis, and Environmental Assessment
(see the Supporting Documentation section of this notice).

V. Overview of the Construction and Development 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 Development
Document and the Economic Analysis.

	Construction 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. 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 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 from the C&D site. In most cases these control measures take
the form of BMPs, but in some cases construction sites actively treat a
portion of the discharge using filtration or other treatment
technologies. Erosion and sediment control measures are described
further in the Development Document.

VI. Summary of Data Collection Activities  TC \l1 "V. Summary of Data
Collection Activities

	In developing today’s proposal, EPA gathered and evaluated technical
and economic data from various sources. EPA also used data collected
previously to develop the 2002 proposed C&D rule and the 2004 withdrawal
of the proposed rule.

EPA used these data to estimate costs, pollutant loading reductions,
environmental benefits and economic impacts of various regulatory
options. This section summarizes EPA’s data collection efforts.

A. State Data

	EPA compiled and evaluated existing state program information about the
control of construction site stormwater. EPA collected data by reviewing
state construction general permits, web sites, summary references, state
regulations, and erosion and sediment control design and guidance
manuals. A summary of criteria and standards for construction site
stormwater erosion and sediment control that are implemented by states
are presented in Appendix A of the Development Document for this
proposed rulemaking.

B. National Land Cover Dataset (NLCD)

	The NLCD provides a national source of data on land cover. EPA used
these data to estimate the amount of land across the U.S. that was
converted to development (e.g., from forest or farmland to residential
communities), which in turn was used to estimate the amount of acreage
that may be subject to the requirements of the C&D rule.

The Multi-Resolution Land Characteristics Consortium (MRLC) has produced
the NLCD datasets that created a 30-meter resolution land cover data
layer over the conterminous United States using remote sensing data.
There are approximately 24 billion data points from remote sensing data
that comprise the NLCD database. NLCD data is publicly available for the
years 1992 and 2001.

	Due to new developments in mapping methodology, new sources of input
data, and changes in the mapping legend for the 2001 National Land Cover
Database (NLCD 2001), direct comparison between NLCD 2001 and the 1992
National Land Cover Dataset (NLCD 1992) is difficult. Thus, MRLC
prepared the NLCD 1992/2001 Land Cover Change Product (see
http://www.mrlc.gov/change_detection.asp). The NLCD 1992/2001 Land Cover
Change Product was developed to offer more accurate direct change
analysis between the two products. This land cover change map and all
documents pertaining to it are considered "provisional" until a formal
accuracy assessment can be conducted. Detailed definitions and
discussion of the NLCD 1992/2001 Land Cover Change Product is summarized
in the Development Document.

	EPA estimated the annual number of acres of land converted to
development in the U.S. and used that estimate as a surrogate measure of
the acres of construction activities subject to national effluent
guidelines regulations, since no national database of the number and
size construction activities exists. EPA used estimates of the amount of
construction activity occurring in each state based on NLCD data as a
basis for calculating state-level compliance costs. NLCD data was also
used to estimate the amount of construction activity occurring in each
of the watersheds in the U.S. based on the EPA Reach File cataloging
system (discussed below). Watershed level data (along with other data
sources) was used to estimate the quantity of construction activities
and the associated pollutant loads occurring in each watershed and to
link these loads to stream reaches for modeling of water quality
improvements and benefits estimates.

C. Enhanced River Reach File 1.2 (ERF1)

	EPA used the EPA Reach File 1.2 dataset (ERF1) to summarize land cover
change in drainage area units (or watersheds). ERF1 for the Conterminous
United States is a vector database of approximately 700,000 miles of
streams and open waters in the conterminous United States. ERF1 was
prepared by EPA in 1982 from National Oceanographic and Aeronautical
Administration (NOAA) aeronautical charts having a scale of 1:500,000.
ERF1 contains 67,171 watersheds with a minimum size of 247 acres (1 km2)
and an average size of 30,182 acres (122 km2). ERF1 serves as the
foundation for SPARROW (Spatially Referenced Regressions [of nutrient
transport] on Watershed) modeling (see Section XIV of this proposal for
a discussion of SPARROW).

D. NPDES Notice of Intent (NOI) Data

	As stated above, when a discharger wishes to be authorized to discharge
under a general permit, it files a NOI to be covered under the general
permit. EPA used NOI data to estimate the distribution of construction
activity by site size and development type. Using NOI data, EPA broadly
characterized the construction industry into three land use types
(residential construction, non-residential construction and road/highway
construction). Differentiation of construction activities by site size
and project type was also done for EPA’s technical and economic
analyses. EPA used NOI data from approximately 138,000 permit
applications, containing data from 38 States for construction activities
occurring primarily between the mid-1990s and 2006. Depending on the
state, the number of NOI records available ranged from fewer than 10 to
more than 10,000. The data are available either from a database of
permits processed directly by EPA (referred to as the EPA NOI database)
or from per-state databases obtained independently.

E. Soils Data

	EPA used the State Soil Geographic (STATSGO) data compiled by Penn
State University (  HYPERLINK "http://www.soilinfo.psu.edu/"
http://www.soilinfo.psu.edu/ ) in order to estimate variation in soil
types nationwide. The variation in soil types found within the United
States is a significant factor in estimating sediment discharges,
pollutant load reductions, and stormwater pollution prevention costs for
construction sites. EPA used the STATSGO soils data in support of the
loadings and removal estimates for this proposal. EPA used the Revised
Universal Soil Loss Equation (RUSLE) in combination with the soils data
to determine soil erosion rates from model construction sites in
different areas of the country. EPA used these estimates, in combination
with estimates of pollutant removal efficiencies for the various
technologies evaluated, to estimate sediment discharges from C&D sites
under baseline conditions and under each regulatory option evaluated.
Additional details on the soil data collected can be found in the
Development Document.

F. NOAA Rainfall Data

	Variations in rainfall depth and intensity are also important factors
in determining erosion rates, sediment discharges, pollutant load
reductions and control technology costs for construction sites. In order
to account for variations in rainfall patterns, EPA collected rainfall
data for one indicator city within each of the 48 conterminous states.
Data for each of these indicator cities were used as point estimates for
estimating rainfall depths and intensities for construction activities
for the entire state. A major urban area was chosen as the indicator
city in each state; which in most cases was the capital city.

	For each indicator city, precipitation data was gathered and analyzed
using the National Oceanic and Atmospheric Administration (NOAA)
National Weather Service (NWS) Precipitation Frequency Data Server
(PFDS), NOAA Atlas 14, a series of maps presented in older NWS
publications, and NOAA Atlas 2 (Precipitation Frequency Atlas of the
Western United States, (1973)). Alaska and Hawaii, as well as the U.S.
territories, were not included in this analysis because EPA lacked
sufficient data on the annual amount of construction occurring in these
areas. More details on EPA’s analysis can be found in the Development
Document.

G. Parameter Elevation Regressions on Independent Slopes Model (PRISM)

	PRISM is a climate mapping system that was used to estimate the annual
acres that would be subject to the regulatory options given various
annual rainfall cut-offs. Using PRISM GIS layers of average annual
precipitation along with RF1-level estimates of annual acres of new
construction, EPA was able to estimate acres that would be subject to
various regulatory options given various average annual precipitation
cutoffs.

H. Revised Universal Soil Loss Equation (RUSLE) R Factors

	EPA used maps of rainfall-runoff erosivity factors (or R factors)
contained in the RUSLE documentation. These maps, in GIS form, along
with RF1-level estimates of annual acres of new construction, were used
to estimate acres that would be subject to regulations given various R
factor values.

I. Economic Data

	EPA utilized various economic data sources in developing today’s
proposal. The primary data source is the 2002 Economic Census, conducted
every five years by the U.S. Census Bureau. The U.S. Small Business
Administration (SBA) and Census Bureau also provide important
information in Statistics of U.S. Business (SUSB). SUSB provides
firm-level data that is particularly important for the firm and industry
impact assessment and for the small entity analysis. An important source
of project level data is Reed Construction, a commercial construction
industry data service that collects and reports information on
multifamily, commercial/institutional, and industrial construction
projects undertaken nationally. EPA assigned baseline financial
characteristics – balance sheet, income statement, and metrics of
financial performance and condition – to each of the model firms as
defined by NAICS sector and revenue size range, from financial statement
information reported by Risk Management Association’s (RMA)
publication, Annual Statement Studies. The Census Bureau’s 2006
American Community Survey (ACS) was used to characterize new home prices
and lot sizes (2006 was chosen because it is the most recent year for
which the required MSA-level data are available from the Census).

VII. Characteristics of Discharges from Construction Activity  TC \l1
"VII. Storm Water Discharge Characteristics

	The nature of construction activity is that it changes, often
significantly, many elements of the natural environment. Typically,
construction activities involve clearing the land of vegetation,
digging, 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, soil and sand particles
may be easily picked up by wind and/or washed away by rain or snow melt.
Typically, the water carrying these particles eventually reaches a water
body.

	Discharges from construction activity have been documented to increase
the loadings of several pollutants in the receiving waterbodies. The
most prominent and most widespread pollutant discharged from C&D sites
is sediment. The level of sediment is often identified through the
measurement of other pollutants in the water body, most notably
turbidity, suspended solids, total suspended solids (TSS), suspended
sediment concentration (SSC), or settleable solids. CWA section 304(a)
identified suspended solids as a conventional pollutant and in 1978 EPA
defined “suspended solids” as “total suspended solids
(non-filterable) (TSS)” and stated that TSS “is 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). Turbidity and settleable solids are
non-conventional pollutants. See Rybachek v. EPA, 904 F.2d 1276, 1291-92
(9th Cir.1990). The Agency defined “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). (See Section IX for a discussion of why EPA proposes
turbidity as the desired pollutant to control in determining the
appropriate technology).

	Stormwater discharges can have highly variable levels of pollutants, as
reflected by turbidity levels that range from as low as 10-50 NTU to
several thousand NTU. When the denuded and exposed areas contain
nutrients, pathogens, metals or organic compounds, these other
pollutants are likely to be 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 turbidity, pH, water
temperature, or stream flow velocity, as well as changes in biological
characteristics such as aquatic species abundance and composition.

	Actions taken to stabilize disturbed areas of the C&D site can include
seeding to restore vegetative cover. When fertilizers or herbicides are
applied to these areas, a portion of the chemicals applied may become
entrained in stormwater and will be discharged from the site.
Fertilizers contribute nutrients such as nitrogen and phosphorus to the
wastestream.

	Discharges from construction activity are expected to contain varying
concentrations of metals, some of which may be contributed by equipment
used onsite for grading and other construction activities. 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 present as
a contaminant or additive in fertilizers and other soil amendments may
serve as another source of pollutants in the stormwater discharge.

	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, would 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.

	The environmental impacts associated with discharges from construction
sites are described in section XIV.

VIII. Description of Available Technologies

A. Introduction  TC \l2 "A.  Introduction

	As described in Section VII, 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 measures. Construction activities should be
managed to reduce erosion and retain sediment on 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   TC \l2 "B. Erosion and Sediment Controls
and Other Site Management Practices

	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 notice 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, as well as overall erosion and
sediment control costs. This can be accomplished by reducing the overall
area of disturbed land or 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.

	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.

	After land has been disturbed and construction activity has ceased on
any portion of the site, exposed soils should be covered and stabilized
immediately. Vegetative stabilization using annual grasses is a common
practice used to control erosion. Polymers, physical barriers such as
geotextiles, straw, rolled erosion control products and mulch are other
common methods of controlling erosion. 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 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, straw bale dikes, berms or
swales. Trapping devices such as sediment traps and basins and inlet
protectors 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 active treatment processes such as
electrocoagulation, filtration, and chemically-enhanced settling (e.g.,
polymer addition).

	Active treatment systems are typically used in conjunction with other
sediment controls to improve pollutant removals, especially to improve
removals of fine-grained and slowly-settling or non-settleable particles
contained in stormwater. Unless sufficient detention time is provided or
additives are implemented, particles such as clays and fine silts
contained in stormwater discharges from construction sites typically
cannot be effectively removed by conventional stormwater BMPs (such as
sediment basins and sediment traps) that rely solely on gravity
settling. EPA has identified several demonstrated technologies capable
of achieving significant reductions of these particles. Based on the
information in the record, electrocoagulation, polymer clarification,
and chitosan-enhanced filtration treatment technologies are demonstrated
as being capable of achieving low levels of turbidity in stormwater
discharges.

The active treatment systems EPA has evaluated operate by destabilizing
the suspended particles by various mechanisms, aggregating them into
larger particles that are easier to remove through settling or
filtering. In addition to physical characteristics (e.g., particle
surface area, density) that impede timely settling by gravity, these
small particles (often clay particles) typically are substantially
influenced by net electrical repulsive forces at particle surfaces that
prevent the particles from joining together. Coagulation refers to the
process whereby these repulsive electrical forces are reduced, allowing
particles to come into contact with one another. Flocculation refers to
the agglomeration of the destabilized particles by joining and bridging
to form larger particles. Following coagulation/flocculation, the
densified floc can more easily and effectively be removed via
gravitational settling or media filtration (e.g., sand, gravel, bag, or
cartridge filters).

Electrocoagulation treatment uses an electrical field to disturb the
natural electrical charges of the colloidal particles suspended in
stormwater, enabling the particles to coagulate and flocculate, and
facilitating gravity settling. This settling may be followed by
filtration prior to discharge of the stormwater.

Polymer clarification would typically operate as a batch process whereby
a polymer is added to stormwater contained in a basin. The polymer
causes clays and other fine particles to flocculate and gravity settle.
Once the turbidity reaches the necessary value and other permit
requirements are met, the stormwater is discharged from the basin.
Polymer clarification can also be used in flow-through systems. In this
application, liquid polymer is injected into the influent to the
sediment basin or gel or solid polymer is added by placing
polymer-filled socks or “floc logs” in channels or pipes carrying
sediment-laded runoff into the basin. Stormwater flowing over the socks
or logs dissolves the solid polymer, and turbulence at the basin inflow
point facilitates mixing and aids in the coagulation/flocculation
process.

Chitosan-enhanced filtration is a process that adds a polymer (in this
instance, a polymer produced from the chitin in crab shells) to the
stormwater to promote flocculation. The flocculated stormwater is then
passed through one or more filtration steps and, if permit conditions
are met, can be discharged.

These active treatment systems are often equipped with automated
instrumentation to monitor stormwater quality, flow rate, and dosage
control for both influent and effluent flows.

It has been suggested that, while operating active treatment systems
that use polymers to reduce the turbidity of stormwater, construction
site dischargers may overuse polymers and, in doing so, introduce
toxicity or cause other adverse effects. Toxic effects from discharges
treated to meet a turbidity limit should not be occurring and such
events would be indicative of a poorly operated treatment system.
Polymers are widely used at a variety of wastewater treatment systems
and facilities throughout the country, and EPA is not aware of any
studies indicating that polymer addition has been found to pose a
significant risk to water quality at those facilities. There are ample
regulatory (i.e., enforcement actions) and financial (e.g., chemical
costs) disincentives for dischargers to willfully overuse polymers in
their treatment systems. In addition, vendors have indicated that
dosages of polymers are carefully metered in ATS systems. Upon closer
review of the matter, it appears that this concern has been raised due
to anecdotal suggestions, rather than documented evidence of actual
discharge events causing toxic effects. To date, EPA has not identified
any documented cases where the use of a polymer to treat C&D stormwater
discharges caused an adverse effect in the receiving waters. Also,
Washington and other States have researched toxicity of some polymers
and established a sound basis for testing and significant controls on
dosage and usage. Therefore, EPA recognizes the merits of ensuring that
chemical additives are properly used. EPA solicits information and data
that quantify 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. In
addition, EPA solicits comments on the need for approaches (either
voluntary or regulatory) to prevent or minimize the potential for such
instances and the need for EPA to develop guidance on use of polymers at
construction sites.

	More detailed descriptions of sediment and erosion control measures can
be found in the Development Document.

D. Other Construction and Development Site Management Practices   TC \l3
"4. Control of Other Pollutants

	Construction activity generates a variety of wastes and wastewater,
including concrete truck rinsate, 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. Dischargers utilize various practices to manage these wastes and
minimize discharges to surface waters, including:

	•	protecting construction materials, chemicals and fuels and
lubricants from exposure to rainfall

	•	limiting exposure of freshly placed concrete to rainfall

	•	segregating stormwater and other wastewaters from fuels,
lubricants, sanitary wastes, and chemicals such as fertilizers,
pesticides and herbicides.

	• 	neat and orderly storage of chemicals, pesticides, fertilizers,
and fuels that are being stored on the site

	•	prompt collection and management of trash and sanitary waste

	•	prompt cleanup of spills of liquid or dry materials.

IX. Development of Effluent Limitations Guidelines and Standards  TC \l1
"IX.  Development of Effluent Limitation Guidelines and Standards

A.   TC \l2 "B. Regulatory Options Considered Description of the
Regulatory Options Considered

	In developing today's proposal, EPA evaluated several different options
for reducing pollutant discharges from construction activity. The
options evaluated by EPA are intended to control the discharge of
sediment, turbidity and other pollutants in stormwater and other
wastewater from C&D sites. Construction activity typically involves
clearing, grading and excavating of land areas. Prior to construction,
these land areas may have been agricultural, forested or other
undeveloped lands. Construction can also occur as redevelopment of
existing rural or urban areas, or infill development on open space
within existing developed areas. During the C&D process, vegetation or
surface cover is typically removed and underlying soils become more
susceptible to detachment by rainfall and erosion by stormwater runoff.
Soil is often compacted by construction equipment, reducing the
infiltration capacity of underlying soils and increasing stormwater
discharge rates. Sediments and other pollutants contained in stormwater
can and often are transported off-site and discharged from construction
sites. Today's proposal provides regulatory tools to improve erosion and
sediment control measures and pollution prevention measures on C&D sites
to minimize and control stormwater and other discharges from
construction activity.

	Certain limitations being proposed today are common to each regulatory
option. These common requirements consist of a set of non-numeric
effluent limitations that require dischargers to provide and maintain
effective erosion control measures, sediment control measures, and other
pollution prevention measures to minimize the discharge of pollutants in
stormwater and other wastewater from construction sites. These
non-numeric effluent limitations included in each regulatory option are
described in Section IX.B below.

B. Effluent Limitations Included in All Regulatory Options

		EPA's preferred approach is twofold: first, prevent the discharges of
sediment and other pollutants from occurring through the use of
effective site-specific planning, erosion control measures and pollution
prevention measures; and second, control discharges that do occur
through the use of effective sediment control measures. Under each
regulatory option, dischargers would be required to meet non-numeric
effluent limitations requiring them to minimize and control discharges
from the site by providing and maintaining effective erosion and
sediment control measures and pollution prevention measures.

	Dischargers would be required to prevent soil erosion and minimize the
discharge of sediment from all areas of the site by providing and
maintaining effective erosion control measures. Erosion controls are
considered effective when bare soil is uniformly and evenly covered with
vegetation or other suitable materials, stormwater is controlled so that
rills and gullies are not visible, and channels and streambanks are not
eroding. Dischargers would be required to provide and maintain
recognized and accepted erosion control measures, including stabilizing
disturbed soils immediately after clearing, grading, or excavating
activities have permanently or temporarily ceased (i.e., when such
activities have been stopped on a portion of the site and will not
resume for a period exceeding 14 calendar days). In addition,
dischargers would be required to minimize the amount of soil exposed and
control stormwater within the site to prevent soil erosion by using
effective erosion control measures. Stormwater discharges leaving the
site would also need to be controlled to prevent channel and streambank
erosion and erosion at outlets.

	The following list of principles and practices are generally recognized
and accepted as effective erosion controls and would be provided in the
rule to help guide the selection, design, and implementation of control
measures to meet the effluent limitations on individual construction
sites.

Preserve topsoil and natural vegetation

Minimize soil compaction

Sequence or phase construction activities to minimize the areas
disturbed at any one time

Stabilize disturbed areas using temporary or permanent vegetation, and
controls such as mulch, geotextiles, or sod

Minimize the disturbance of steep slopes, and where such slopes are
disturbed implement erosion controls designed to control soil erosion on
slopes

Establish and maintain natural buffers around surface waters

Minimize the construction of stream crossings

Divert stormwater that may run onto the site away from any disturbed
areas of the site.

	Dischargers would also be required to meet non-numeric effluent limits
requiring that they provide and maintain effective sediment controls to
minimize the discharge of sediment and other pollutants from C&D sites.
Sediment control measures implemented at the site would include, at a
minimum, the following:

Establishing perimeter controls for any portion of the down-slope and
side-slope perimeter where stormwater will be discharged from disturbed
areas of the site

Establishing and using stabilized construction entrances and exits that
control sediment discharges from the site. Ensuring that vehicles
entering and exiting the site use such access points to prevent tracking
of sediment onto roads or other areas that convey sediment to surface
waters. Removing any sediment or other pollutants, including
construction materials, from paved surfaces daily. Washing sediment or
other pollutants off paved surfaces into storm drains would be
prohibited

Establishing and using controls and practices to minimize the
introduction of sediment and other pollutants to storm drain inlets that
receive stormwater discharges from the site

Controlling sediment and other contaminants from dewatering activities.
Discharges of dewatering wastes are prohibited unless treated in a
sediment basin or similar control measure

	Each regulatory option includes pollution prevention measures that
would minimize or prohibit the discharge of pollutants from a variety of
sources and activities at C&D sites. Each option would prohibit
discharges of construction wastes, trash, sanitary wastes, and
wastewater from washout of concrete, paint, and other such materials.
The regulatory options would also prohibit the discharge of fuels, oils,
and other materials used in vehicle and equipment operation and
maintenance. The discharge of wastewater from washing vehicles and
equipment where soaps or solvents are used would be prohibited. The
discharge of pollutants resulting from the washing of equipment and
vehicles using plain water would also be prohibited, unless wash waters
were treated in a sediment basin or alternative control that provides
equivalent or better treatment. Dischargers would be required to
implement measures to minimize the exposure of stormwater to building
materials, landscape materials, fertilizers, pesticides, herbicides,
detergents, and other liquid or dry products. In addition, dischargers
would be required to implement appropriate spill prevention and response
procedures for these materials.

C. Options for BPT, BCT, BAT and NSPS

EPA considered the following three regulatory options for today’s
proposal.

• Option 1

	Each C&D site subject to the rule would be required to implement the
limitations described above in Section IX.B. In addition, certain larger
sites would be required to install and maintain sediment basins or
equivalent sediment controls. Specifically, for portions of sites that
drain to one location and will have 10 or more acres disturbed at one
time, dischargers would be required to install a sediment basin to
control and treat the stormwater discharges. The proposed rule would
impose minimum standards of design and performance for sediment basins.
The basin would be required to provide storage for a calculated volume
of stormwater (called the water storage volume) from a 2-year, 24-hour
storm from each disturbed acre drained until final stabilization of the
disturbed area. Where no such engineering calculation had been
performed, a sediment basin providing a water storage volume of 3,600
cubic feet per acre drained would be required. To ensure adequate
retention time to facilitate settling of sediment particles, the
proposed rule would require that the effective length of the basin must
be at least four times the width of the basin and that the water quality
volume be designed to drain over a period of at least 72 hours using a
surface outlet (such as a skimmer), unless otherwise designated by the
permitting authority. The size of the basin that would be required is
based on the size of the drainage area that will have vegetation removed
and soils disturbed (i.e., if the total drainage area is 15 acres, but
only 13 acres of this area will have vegetation removed and soils
disturbed during the course of the project and the remaining 2 acres
will remain vegetated and stormwater is directed around both the
disturbed area and the sediment basin, then the storage volume can be
sized based on 13 acres).

	In addition, the design of the sediment basin would be required to
address site-specific factors such as amount, frequency, intensity and
duration of stormwater runoff; soil types; and other factors affecting
pollutant removal efficacy. For example, particle settling
characteristics, and thus pollutant removal efficacy, can be affected by
physical parameters of the basin such as inlet and outlet velocities,
basin surface area, and basin depth and volume necessary to provide
sufficient storage for sediment load and stormwater runoff. Effective
erosion and sediment controls are generally recognized as including
actions to divert stormwater away from disturbed areas of the site, so
that sediment erosion is reduced and sediment controls, such as basins,
are not overwhelmed by stormwater volumes.

	To minimize carryover and discharge of suspended particles from the
sediment basin, the basins would be required to incorporate an outlet
device designed to remove water from the top of the water column in
order to minimize the amount of sediment and other pollutants entrained
in the discharge. This can be accomplished by using technologies such as
a siphoning outlet, surface skimmer or floating weir.

	Recognizing that there may be impediments to using sediment basins in
some instances or that alternative approaches may provide better
controls depending on site-specific conditions, the proposed rule would
authorize dischargers to use alternative controls equivalent to sediment
basins where approved by the permitting authority.

	EPA encourages dischargers to use improved sediment basin designs that
incorporate features such as baffles and to increase the length to width
ratio of the basin to maximize detention time and settling. The use of
these practices may significantly improve the performance of sediment
basins in certain cases. The North Carolina Department of Transportation
(NCDOT) has developed draft specifications for baffles in sediment
basins (see DCN XXXXX). EPA solicits comments on whether porous baffles,
as described in the draft NCDOT specifications, should be minimum
requirements for all sediment basins nationwide. EPA also requests
comments on the costs and effectiveness of baffles used in sediment
basins, either alone or in combination with skimmers and polymer
addition. EPA also solicits comments on the detention time requirements
for sediment basins contained in today’s proposal, and whether the
proposed rule should include other specific detention time, overflow
rate or other design or performance requirements for sediment basins.
EPA also solicits comments on whether the regulation should require that
sediment basins be designed to remove a specified particle size. EPA
also requests comments on whether sediment basin designs should be
required to address downstream channel erosion by requiring peak or
discharge rates to match predevelopment conditions, and for what storm
events such a standard should apply.

	Option 1 is estimated to cost approximately $132 million per year (2008
$), not including costs for Alaska, Hawaii and the U.S. territories, and
reduce discharges of pollutants by about 670 million pounds annually.

	While developing and evaluating Option 1, EPA considered several
possible variations for sediment basin requirements. One approach would
have eliminated flexibility for dischargers to use a 3600 cf/acre basin
in lieu of the 2-year, 24-hour basin. In effect, all sites required to
install a sediment basin under Option 1 would have been required to
construct a basin sized to treat runoff from the 2-yr, 24-hour storm (or
use equivalent control measures). EPA estimated that this variation of
Option 1 would cost approximately $1.09 billion per year. EPA also
considered an approach that, in addition to specifying a particular size
of basin, would require that the sediment basin be sized and constructed
to enable settling of a specified-size particle – e.g., 10-micron
particles. This approach would be a design standard rather than a
numeric limitation on the sediment basin effluent. . For example, the
California Stormwater Quality Association Construction Handbook (see DCN
XXXXX) contains an example of designing a sediment basin to remove a
specified particle size standard based on wet sieve analysis or the 10
micron particle for a 10-year, 6-hour storm event. EPA estimates, using
this approach, sediment basins required to remove particles greater than
10 microns nationwide would cost approximately $1.6 billion per year.
More information about these potential sediment basin approaches is
presented in the Development Document. EPA solicits comment on whether
Option 1 or other variations described here would be appropriate
regulatory approaches and, if so, why, based on the statutory
requirements of CWA section 304, they should be considered to represent
BPT, BCT, BAT, or NSPS level of control for this industry.

• Option 2

	The requirements that would be established under Option 2 incorporate
all of the Option 1 requirements. In addition, a numeric limit on
turbidity of stormwater discharges would apply to sites that meet
certain criteria for size of disturbed area, average clay content of the
soil (with clay content being defined as soil particles less than 2
microns in diameter), and rainfall erosivity factor (“R factor”) as
defined by the Revised Universal Soil Loss Equation (see Predicting Soil
Erosion by Water: A Guide to Conservation Planning With the Revised
Universal Soil Loss Equation (RUSLE), United States Department of
Agriculture, Agriculture Handbook Number 703, January 1997). Option 2
would establish a numeric effluent limit on the turbidity of stormwater
discharges for any site that meets all three of the following criteria:
(1) average soil clay content of more than 10 percent; (2) Annual R
factor of 50 or more; and (3) has a size of 30 or more acres. The
numeric turbidity standard would apply to discharges produced from
rainfall events up to the local 2-year, 24-hour storm. Any volume in
excess of the 2-year, 24-hour storm would be exempt from the turbidity
standard. The turbidity limitation would apply to these sites in
addition to the Option 1 requirements (i.e., such sites would also be
required to implement the non-numeric erosion and sediment control
measures described under Option 1). Under Option 2, dischargers would be
required to monitor stormwater discharges for turbidity, which can be
done either by using automated instrumentation or with a portable,
hand-held turbidimeter or similar device. Sites with 10 or more acres of
disturbed land that are not required to meet the turbidity requirement
because the R factor is less than 50 or the average clay content of
soils is less than 10 percent would be required to install sediment
basins as described under Option 1. Site size for sites subject to the
proposed turbidity limit is based on the total size of the site, not the
amount of disturbed acres or some other subset of the site. Any site
which is 30 acres or larger regardless of how much of the site will be
disturbed would be subject to the turbidity limit if they also meet the
R factor and soil clay content thresholds.

By considering the construction site’s soil clay content, this option
takes into account the pollutant reductions that are achievable using
the erosion control measures and traditional sediment control measures
(i.e., those other than active treatment systems) included in the
proposed rule. These more traditional approaches to controlling
stormwater discharges can be very effective in soils with low clay
content where the entrained sediment is amenable to gravity settling.
However, as the amount of clay in the soil rises, gravity settling
processes are less effective and processes to enhance the removal of
pollutants from stormwater are necessary. By applying the proposed
turbidity limit in Option 2 to sites with high clay content, the
proposed rule would achieve significant reductions of the
slowly-settling or non-settleable particles contained in stormwater. In
order to remove these fine-grained particles from stormwater discharges,
active treatment technologies, such as those described in Section VIII,
typically would need to be employed. The information in the record shows
that these systems can achieve low levels of turbidity in the stormwater
discharges.

While it is impossible to predict the weather several months in advance
of construction, for many areas of the country, there are definite
optimal periods for conducting construction activities in order to limit
soil erosion, such as a dry season when rain tends to fall less
frequently and with less force. When feasible, this is the time to
disturb the earth, so that the site is stabilized by the time the
seasonal wet weather returns. The R factor is intended to reflect
consideration of the amount and intensity of precipitation expected
during the time the earth will be exposed.

The method for determining a site’s R factor is based on the Universal
Soil Loss Equation (USLE) developed by the U.S. Department of
Agriculture (USDA) in the 1950s to help farmers conserve topsoil. The
USLE has been updated to the Revised USLE (RUSLE). Using a computer
model supported by decades worth of rainfall data, USDA established
estimates of rainfall erosivity factors (R) for sites throughout the
country. These R factors are used as surrogate measures of the impact
that rainfall has on erosion from a particular site. The R factor
represents the driving force for erosion, taking into consideration
total rainfall, intensity and seasonal distribution of the rain.
Isoerodent maps depicting the R factor in various parts of the country
have been created by USDA and are included in Chapter 2 of Agriculture
Handbook Number 703.

While developing and evaluating Option 2, EPA considered several
possible variations for the applicability of a limitation on turbidity
of stormwater discharges. One approach would replace the R factor
criteria with one based on total annual rainfall for the site location.
Under this approach, EPA preliminarily considered values of 20-inches
and 40-inches total annual rainfall. EPA considers the R factor approach
better than total annual rainfall at addressing stormwater discharges
because the R factor captures both rainfall energy (a function of the
volume of rainfall and runoff) and intensity (which has direct bearing
on the erosive power of a rainfall event). EPA has structured the
regulatory option accordingly. However, since R factors have not been
calculated for all areas of Alaska and the U.S. territories, a criterion
of 20-inches total annual rainfall (30-year average using National
Weather Service records) has been retained as a substitute for R factor
for construction sites in those locations unless an R factor applicable
to the construction site is calculated.

EPA also considered approaches that would apply the turbidity effluent
limitation to larger sites (e.g., 50 acres instead of 30 acres) or with
higher clay content of the soil (e.g., 20 percent instead of 10 percent
clay). More information about these potential approaches is presented in
the Development Document. EPA solicits comment on whether Option 2 or
other combinations of rainfall, clay content and acreage limitations
like those described above would be more appropriate regulatory
approaches and, if so, why, based on the statutory requirements of CWA
section 304, they should be considered to represent BPT, BCT, BAT, or
NSPS level of control for this industry.

EPA evaluated the advantages and disadvantages of establishing a
limitation on turbidity vs. total suspended solids (TSS) in stormwater
discharges from construction sites. EPA selected turbidity for two
reasons. First, EPA is specifically targeting fine silt, clay and
colloidal particles in stormwater runoff. These particles have small
diameters and frequently contain a surface charge that prevents
agglomeration. As a result, these particles typically do not settle in
sediment basins and are not effectively removed by conventional BMPs
such as silt fences, which have a large pore diameter. Consequently,
discharges from sites with appreciable clay soils may have low TSS
concentrations but may still have high turbidity levels. Second,
turbidity can be easily measured in the field while TSS requires
collection of a sample and analysis in a laboratory. Since most BMPs and
treatment systems are flow-through systems, TSS would not be a practical
means of estimating compliance because permittees would not be able to
verify whether or not they had met the standard before discharging. With
turbidity, permittees can measure turbidity levels in discharges
continuously and adjust treatment parameters accordingly or recycle
effluent if they are in danger of exceeding the turbidity limit. For
these reasons, EPA believes that turbidity is a more appropriate measure
of effectiveness and can be implemented more easily than TSS. EPA
requests comments on this approach.

	Option 2 is estimated to cost up to$1.9 billion per year (2008 $), not
including costs for Alaska, Hawaii and the U.S. territories, and reduce
discharges of pollutants by up to 27 billion pounds annually.

• Option 3

	Under Option 3, all sites with common drainage locations that serve an
area with 10 or more acres disturbed at one time would be required to
comply with the turbidity effluent limitation (in addition to the
non-numeric effluent limitations in Option 1). This option does not
establish thresholds for R factor (or total annual rainfall) or soil
type (i.e., clay content). Under this option, all other sites (i.e.,
sites with less than 10 acres disturbed at one time) would be required
to implement the requirements described under Option 1 (for sites with
common drainage locations that serve an area of less than 10 acres
disturbed at one time).

	Option 3 is estimated to cost up to $3.8 billion per year (2008 $), not
including costs for Alaska, Hawaii and the U.S. territories, and reduce
discharges of pollutants by up to 50 billion pounds annually.

D. Option Selection Rationale for Best BPT

	EPA proposes to select Option 1 as the basis for establishing BPT
effluent limitations. The requirements established by Option 1 are
well-established by construction activities in all parts of the country
and are consistent with the control measures currently in place under
EPA’s Construction General Permit and many state general permits. EPA
has determined that Option 1 represents a level of control that is
technologically available and economically practicable. EPA considered
the non-water quality environmental impacts of this option and found
them to be minimal and thus acceptable. Selecting Option 1 as BPT for
this point source category is consistent with the CWA and regulatory
determinations made for other point source categories, in that the
Option 1 requirements represent limitations based on the average of the
best performance of facilities within the C&D industry. See Weyerhauser
Co. v. Costle, 590 F.2d 1011, 1053-54 (D.C.Cir.1978). As stated in
Section III, EPA assesses cost-reasonableness of BPT effluent
limitations by considering the cost of treatment in relation to the
effluent reduction benefits achieved. EPA has determined that the
pollutant reduction benefits achieved by Option 1 justify the costs. We
have typically described this as dollars/pound and compare the results
with other rules. The incremental costs of Option 1 are approximately
$132 million per year (2008 $). EPA anticipates that construction sites
in approximately 11 states would incur costs to comply with the proposed
Option 1 BPT requirements requiring sediment basins consistent with the
EPA CGP, reducing pollutant discharges by approximately 670 million
pounds per year.

	EPA rejected Options 2 and 3 because EPA views BPT performance as the
first level of technology-based control representing the average of the
best performance. EPA’s record does not indicate that meeting a
turbidity limit, even for the subset of facilities identified in Option
2 would represent today’s average of the best performance and it would
not represent the BPT level of control for this point source category.
EPA requests comment on what should be considered BPT for this category

E. Option Selection Rationale for BAT and NSPS

1. Selection Rationale

	EPA has selected Option 2 as the basis for BAT and NSPS. This option
would require all C&D sites to implement the non-numeric effluent
limitations described for Option 1, as well as requiring certain sites
to meet a numeric limitation of 13 NTU (nephelometric turbidity units)
to control turbidity for stormwater discharges. Turbidity is being
regulated in this proposed rule as a nonconventional pollutant and an
indicator pollutant for the control of other pollutants associated with
sediment and materials on construction sites that can become entrained
in stormwater discharges from construction sites, including metals and
nutrients. Turbidity, measured as NTU, is a nonconventional pollutant
because it is not identified as either a toxic or conventional pollutant
under the CWA. See CWA section 304(a)(4); 40 CFR 401.16; Rybachek v.
EPA, 904 F.2d 1276, 1291-92 (9th Cir.1990). Turbidity is “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). In this rulemaking, EPA is identifying turbidity as a
pollutant of concern in construction site discharges. By providing a
measure of the sediment entrained in stormwater discharges, turbidity is
an indicator of the degree to which sediment and other pollutants
associated with sediment and found in stormwater discharges are reduced.
Turbidity is also a more effective measure of the presence of fine
silts, clays and colloids, which are the particles in stormwater
discharges that EPA is specifically targeting in today’s proposal.

	Metals, nutrients, and other toxic and nonconventional pollutants are
naturally present in soils, and can also be contributed by
equipment/materials used during construction or by activities that
occurred at the site prior to the construction activity. 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). EPA has determined that effluent
limitations that reduce turbidity in the stormwater discharge will also
achieve reductions of the other pollutants of concern. Demonstrating
compliance with a turbidity limit would be relatively easy and
inexpensive for construction site dischargers to implement. Hand-held
turbidity meters (turbidimeters) can be used to measure turbidity in
discharges, or data loggers coupled with in-line turbidity meters can be
used to automatically measure and log turbidity measurement reducing
labor requirements associated with sampling. In addition, the use of
turbidity meters will provide dischargers with immediate, real-time
information on the efficacy of their treatment systems and sediment
controls measures to facilitate timely adjustments of system operation
where necessary.

	The requirements of Option 2 have been demonstrated to be
technologically available. Active treatment systems have been used and
are currently being used at several hundred construction sites
throughout the country. Construction sites where these active treatment
systems have been used are primarily located in California, Oregon and
Washington, with some in Florida, Maryland, Vermont and other states.
Oregon requires sites to meet a 160 NTU benchmark if the site is
discharging to a waterbody listed as not meeting applicable water
quality standards under section 303(d) or a waterbody with a total
maximum daily load (TMDL) for sediment and turbidity. Washington has
turbidity benchmark limits that are set at values relative to the
turbidity in the receiving steam. Vermont requires what it defines as
“moderate risk” projects to take corrective action if turbidity
exceeds 25 NTUs. Also, several other states have turbidity limitations
or standards that are either in draft permits (such as California), are
set relative to background levels (Georgia), or are set only for
specific regions or specific waterbodies within the state (such as the
Lake Tahoe Basin of California) or for specific construction projects
(such as construction of a new runway at the Sea-Tac airport). To comply
with these turbidity criteria, dischargers have used the active
treatment systems described previously – electrocoagulation, polymer
clarification, and chitosan-enhanced sand filtration. The information in
the record demonstrates the efficacy of these treatment systems, showing
that they consistently achieve very low levels of turbidity in
stormwater discharges.

	The selection of Option 2 is consistent with recommendations of the
National Research Council (NRC). EPA commissioned the NRC to evaluate
the NPDES stormwater program and make recommendations for improvement of
the program. The Water Sciences and Technology Board released the report
Urban Stormwater Management in the United States (Committee on Reducing
Stormwater Discharge Contributions to Water Pollution, National Research
Council, National Academies Press) in October of 2008. The report is the
product of a 2-year process undertaken by a 15-member committee of
national experts.

	While the report did not specifically endorse numeric effluent limits
for construction site, the report did contain several recommendations,
including that “Numeric enforcement criteria can be used to define
what constitutes an egregious water quality violation at construction
sites and provide a technical criterion to measure the effectiveness of
erosion and sediment control practices.”  The study continues to
report that “A maximum turbidity limit would establish definitive
criteria as to what constitutes a direct sediment control violation and
trigger an assessment for remediation and prevention actions. For
example, local erosion and sediment control ordinances could establish a
numeric turbidity limit of 75 Nephelometric Turbidity Units (NTU) as an
instantaneous maximum for rainfall events less than an inch (or a 25 NTU
monthly average) and would prohibit visible sediment in water discharged
from upland construction sites. While the exact turbidity limit would
need to be derived on a regional basis to reflect geology, soils, and
receiving water sensitivity, research conducted in the Puget Sound of
Washington indicates that turbidity limits in the 25 to 75 NTU can be
consistently achieved at most highway construction sites using current
erosion and sediment control technology that is properly maintained
(Horner et al., 1990). If turbidity limits are exceeded, a detailed
assessment of site conditions and follow-up remediation actions would be
required. If turbidity limits continue to be exceeded, penalties and
enforcement actions would be imposed. Enforcement of turbidity limits
could be performed either by state, local, or third party erosion and
sediment control inspectors, or—under appropriate protocols, training,
and documentation—by citizens or watershed groups.”

	Although the NRC report reports recommended turbidity limits of 25 and
75 NTUs, which are higher than the proposed limit of 13 NTUs in
today’s proposal, EPA’s analysis of ATS effluent data from more than
6,000 data points indicates that a limit of 13 NTUs is attainable.

	California assembled a blue ribbon panel to evaluate, among other
things, the feasibility of establishing numeric effluent limits from
construction sites (see DCN XXX). The blue ribbon panel found that “It
is the consensus of the Panel that active treatment technologies make
Numeric Limits technically feasible for pollutants commonly associated
with stormwater discharges from construction sites (e.g. TSS and
turbidity) for larger construction sites. Technical practicalities and
cost-effectiveness may make these technologies less feasible for smaller
sites, including small drainages within a larger site, as these
technologies have seen limited use at small construction sites. If
chemical addition is not permitted, then Numeric Limits are not likely
feasible.”

	EPA’s selection of Option 2, which requires a turbidity limit only
for larger sites, is therefore consistent with the panel’s conclusion.
EPA notes that although the panel mentions that a numeric limit is not
feasible without chemical addition (e.g., polymers) there are
technologies available (such as electrocoagulation) that do not use
polymers.

	The panel, in determining that numeric effluent limits are technically
feasible, did express concerns, including cost-effectiveness for small
sites, toxicity of treatment chemicals, and the potential for discharges
with low TSS and turbidity into receiving waters with high background
levels (such as in some arid and semi-arid areas) contributing to
channel erosion. EPA has determined that Option 2 addresses these
concerns, because the turbidity standard only applies to larger sites
and does not apply in arid and semi-arid areas because of the R-factor
applicability criteria. EPA is soliciting comment on the need for
regulatory requirements or guidance to address the concerns regarding
potential toxicity of treatment chemicals.

	EPA’s analyses show that the requirements of Option 2 are
economically achievable. Option 2 is projected to have a total industry
compliance cost, once fully implemented in NPDES permits, of $1.9
billion per year (2008 $). Since EPA expects that the effluent
guidelines requirements will be implemented over time as states revise
their general permits, EPA expects full implementation within five years
of the effective date of the final rule, currently required to be
promulgated in December 2009, which would be 2014. EPA estimates that,
once fully implemented, there will be nearly 82,000 firms that perform
work falling within scope of Option 2. Average annual revenue for these
in-scope firms is $544.14 billion (2008 $). Option 2 compliance costs
are 0.35 percent of in-scope firm revenues.

	Under Option 2, an estimated 1,032 firms (1.3 percent of all in-scope
firms) are estimated to incur compliance costs exceeding 1 percent of
annual revenue, and 76 firms (0.1 percent of in-scope firms) are
expected to incur compliance costs exceeding 3 percent of revenue. When
the firms' ability to pass some of their compliance costs along to
customers is accounted for (85 percent of costs for residential
construction and 71 percent for non-residential), there are 20 firms
estimated to incur (net) costs exceeding 1 percent of revenue, and no
firms expected to incur costs exceeding 3 percent of revenue.

	Assuming a cost pass-through rate of 85 percent for residential sectors
and 71 percent for non-residential and non-building sectors, a total of
179 firms are estimated to incur financial stress as a result of
regulatory requirements, which represents 0.2 percent of in-scope firms,
and a total of 132 firms are estimated to experience negative business
value and be at risk of closure due to regulatory requirements, which
represents 0.2 percent of in-scope firms. These impact measures are not
necessarily additive, as they evaluate different aspects of a firm's
financial viability, and the same firm may be counted under more than
one measure. Nevertheless, given the consistently low measures of
financial impact, in terms of percentage of in-scope firms, EPA
considers the rule to be economically achievable by the construction
industry. In addition, these impacts do not take into consideration less
costly ways for industry to comply with the final rule, if it is
promulgated as proposed. One primary way a company could avoid being
subject to the turbidity limit on sites of 30 or more acres would be to
decide to only undertake projects smaller than 30 acres in the future,
thus lowering their potential compliance costs.

	EPA’s analysis shows that Option 2 has acceptable non-water quality
environmental impacts. The pollution prevention, sediment and erosion
control measures included in the proposed rule, including the collection
and treatment of stormwater at some construction sites, will not result
in a significant incremental increase in the energy consumption, air
emissions, or generation of solid waste at construction sites.

	 EPA rejected Option 1 as the basis for BAT and NSPS in part because it
would not represent the best available or best demonstrated technology
for controlling discharges from this industry. Narrative effluent
limitations, such as those contained in Option 1, to prevent and
minimize erosion and sediment dischargers have been a feature of NPDES
permits for many years. Controls are available and demonstrated that
provide a higher degree of pollution reduction than Option 1 and
consistently provide low turbidity values, making a numeric turbidity
limit feasible. In addition, in considering economic achievability of
the option, EPA found that the measures of affordability EPA has used in
the past, facility closure and firm failure, and the firm stress metric
used in Regulatory Flexibility Analysis also considered here (percent of
revenue lost and whether that measure is above 1 or 3 percent)
demonstrate that a Option 2 could reasonably be afforded by the
industry.

	EPA also rejected Option 3 as the basis for BAT and NSPS, due primarily
to the total industry cost (estimated at $3.8 billion annually). Option
3, once fully implemented, would cost $1.9 billion more annually than
Option 2. EPA closely evaluated whether establishing a turbidity limit
on all construction sites disturbing more than 10 acres at a time
represents the BAT or NSPS level of control - - and determined that it
does not. Option 3 would require all construction sites, in every part
of the country and at all times of the year, to meet a numeric effluent
limitation on turbidity if the construction activity disturbs 10 or more
acres of land at a time. Construction sites that have soils containing
relatively little clay (e.g., a site in coastal Florida with sandy
soils) or with low rainfall-runoff erosivity (such as those in certain
parts of Idaho) can likely control the discharge of sediments and other
pollutants through effective use of the erosion and sediment control
measures included in the non-numeric effluent limitations being proposed
today. With relatively little of the difficult-to-settle clay present,
and with low rainfall energy, sediment production is expected to be low
and EPA expects much of the sediment to be removed from stormwater
through the use of effective sediment controls. Therefore, EPA has
determined that requiring these sites to meet a numeric turbidity limit,
including the additional costs for monitoring that a numeric turbidity
limit would impose, does not represent BAT for these sites. EPA solicits
comments on this approach.

	In light of the high total cost of Option 3 and the appropriateness of
ELG and NSPS turbidity limits in arid areas and at construction sites
where rainfall energy is low and soils contain little clay, EPA
determined that Option 3 does not represent the best available or best
demonstrated technology for the C&D point source category.

	In summary, EPA has determined that Option 2 is technologically
available, economically achievable, and has acceptable non-water quality
environmental impacts. EPA has determined that establishing a numeric
turbidity limitation on a segment of the point source category
represents best available and best available demonstrated technology for
the C&D industry, striking an appropriate balance that addresses the
factors EPA is required to consider under the CWA and the nature of
stormwater discharges from construction sites. In addition, EPA has
determined that the non-numeric effluent limitations being proposed
under Option 2 represent best available and best available demonstrated
technology for all dischargers in the C&D industry.

	Although EPA has proposed Option 2 as a basis for BAT and NSPS, EPA is
soliciting comment on the appropriateness of the numeric turbidity limit
of 13 NTUs and the technology basis (i.e., ATS) for Option 2. EPA has
identified information that indicates that a limit of 50 NTUs might be
met by relying on passive, rather than active, treatment systems.
Passive treatment systems consist of a number of techniques that do not
rely on pumping of stormwater or mechanical filtration and that are not
as complex as ATS.

	Data in the literature indicate that passive systems may be able to
provide a high level of turbidity reduction at a significantly lower
cost than active treatment systems. For example, McLaughlin (see DCN
XXXXX) evaluated several modifications to standard sediment trap designs