WAIS Document Retrieval\[Federal Register: July 7, 1998 (Volume 63,
Number 129)\]

\[Proposed Rules\]

\[Page 36741-36806\]

From the Federal Register Online via GPO Access \[wais.access.gpo.gov\]

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Part II

Environmental Protection Agency

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40 CFR Part 131

Water Quality Standards Regulation; Proposed Rule

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 131

\[FRL-0W-6118-9\]

RIN-2040-AC56

Water Quality Standards Regulation

AGENCY: Environmental Protection Agency.

ACTION: Advance notice of proposed rulemaking.

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SUMMARY: EPA is today publishing this advance notice of proposed rule

making (ANPRM) seeking comments from interested parties on possible

revisions to the Water Quality Standards Regulation at 40 CFR Part 131.

This ANPRM is intended to initiate discussions on what if any changes

are needed in the national water quality standards program to improve

the effectiveness of water quality standards in restoring and

maintaining the quality of the Nation\'s waters. EPA will consider all

comments before deciding whether to propose revisions to the

regulation. EPA is particularly interested in comments on certain key

portions of the current Water Quality Standards Regulation (the

regulation) contained in 40 CFR Part 131, which establishes

requirements for adoption of water quality standards pursuant to

section 303 of the Clean Water Act (CWA or the Act). This ANPRM

identifies specific issues on which EPA solicits comment. In addition

to the specific issues on which EPA solicits comments, EPA is

interested in comments on any other aspects of the program. EPA

requests comments with the objectives of: supporting watershed or

place-based environmental water quality management, ensuring that

current water quality criteria and water quality assessment science can

be easily incorporated into State and Tribal water quality programs,

and enhancing effective implementation of the Act.

DATES: Written comments must be submitted by midnight January 4, 1999.

ADDRESSES: Send written comments to W-98-01, WQS-ANPRM Comment Clerk,

Water Docket, MC 4101, US EPA, 401 M Street, S.W., Washington, D.C.

20460\. Comments may also be submitted electronically to OW-

Docket@epamail.epa.gov. The record is available for inspection from

9:00 to 4:00 p.m., Monday through Friday, excluding legal holidays at

the Water Docket, East Tower Basement, USEPA, 401 M St., S.W.,

Washington, D.C. For access to docket materials, please call (202) 260-

3027 to schedule an appointment.

FOR FURTHER INFORMATION CONTACT: Rob Wood at U.S. EPA Standards and

Applied Science Division (4305), 401 M Street SW, Washington, DC 20460

(e-mail: WOOD.ROBERT@EPA.GOV) (telephone: 202-260-9536).

SUPPLEMENTARY INFORMATION: EPA will hold a series of full-day public

meetings for the purpose of discussion and debate on the issues

presented in this notice. EPA plans to hold the public meetings during

the 180-day public comment period on this notice. Dates, times and

locations of public meetings will be announced to the public.

A. Potentially Affected Entities

This ANPRM by itself will have no regulatory impact or effect. The

ANPRM does contain EPA interpretations of core areas of the regulation

as well as EPA thinking about how the regulation may need to be

changed. As discussed in more detail below, this ANPRM marks the

beginning of a national dialogue on possible changes to the water

quality standards regulation and program. If changes to the regulation

are proposed and ultimately made final, to the extent such changes

would require and/or authorize changes to State and Tribal water

quality standards, States and authorized Tribes would be affected. If

changes to State and Tribal water quality standards result from any

final rule that EPA may promulgate in the future, entities subject to

compliance with State or Tribal water quality standards would also

potentially be affected. For example, States and Tribes authorized to

implement the National Pollutant Discharge Elimination System (NPDES)

Permit Program would need to ensure that permits they issue include any

limitations on discharges necessary to comply with any water quality

standards established as a result of any subsequent final rulemaking.

Therefore, entities discharging pollutants to waters of the United

States under NPDES could be affected by subsequent proposed and final

rulemaking. Categories and entities that may ultimately be affected

include:

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Examples of potentially

Category affected entities

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State, Tribes and Jurisdictional States, Tribes authorized to

Governments. administer water quality

standards, and jurisdictional

governments.

Industry\...\...\...\...\...\...\...\...\...\.... Industrial dischargers
of

pollutants to waters of the

U.S.

Municipalities\...\...\...\...\...\...\...\.... Publicly-owned treatment
works

discharging pollutants to

waters of the U.S.

\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\--

This table is not intended to be exhaustive, but rather provides a

guide for readers regarding entities that could be affected by any

subsequent final rulemaking. If you have questions regarding the

applicability of this action to a particular entity, consult the person

listed in the preceding FOR FURTHER INFORMATION CONTACT section.

B. Water Docket Information

The record for this notice has been established under docket number

W-98-01 and includes supporting documentation. When submitting written

comments to the Water Docket, (see ADDRESSES section above) please

reference docket number \[W-98-01\] and submit an original and three

copies of your comments and enclosures (including references). To

ensure that EPA can read, understand and therefore properly respond to

comments, the Agency would prefer that commenters cite the specific

question(s) in the notice to which each comment refers. The questions

presented in this notice for public comment are organized by subsection

and numbered. Each question has a unique number (for example

III.B.3.a., question 1) for this purpose.

Comments must be received or postmarked by midnight January 4,

1999\. Commenters who want EPA to acknowledge receipt of their comments

should enclose a self-addressed, stamped envelope. No facsimiles

(faxes) will be accepted.

Electronic comments are encouraged and may be submitted to the

Water Docket (see ADDRESSES section above). Electronic comments must be

submitted as an ASCII file or a WordPerfect file avoiding the use of

special characters and any form of encryption. Electronic comments must

be identified by the docket number, \[W-98-01\], and be received by

midnight of January 4, 1999. Comments and data will also be accepted on

disks in WP5.1 format or

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ASCII file format. No confidential business information (CBI) should be

sent via e-mail.

The remainder of this Supplementary Information section is

organized as follows:

I. Purpose and Objectives of This ANPRM

A. General Purpose and Vision

B. Objectives

II\. Introduction to Water Quality Standards

A. Statutory History

B. Regulatory History

C. Water Quality Guidance for the Great Lakes System

III\. Program Areas for Public Comment

A. Introduction

B. Uses

1\. Background

2\. Refined Designated Uses

3\. Existing Uses

a\. Protection of Existing Uses

4\. Use Attainability

a\. Attainability of Uses

b\. Removal of Designated Uses

c\. Use Attainability Analysis

d\. Alternatives to \`\`Downgrade\'\' of the Designated Use

i\. Variances

ii\. Temporary Standards

iii\. Ambient-based Criteria

C. Criteria

1\. Background

2\. Ambient Water Quality Criteria to Protect Aquatic Life

3\. Site-Specific Criteria

4\. Narrative Water Quality Criteria

5\. State or Tribe Derived Criteria

6\. Water Quality Criteria for Priority Pollutants

7\. Criteria for Non-Priority Pollutants with Toxic Effects

8\. Criteria Where Data or Guidance is Limited

9\. Toxicity Criteria

10\. Sediment Quality Criteria

11\. Biological Criteria

12\. Wildlife Criteria

13\. Physical Criteria

14\. Human Health

a\. Risk Levels

b\. Fish Consumption Assumptions

c\. Maximum Contaminant Levels

15\. Microbiological Criteria

16\. Nutrient Criteria

D. Antidegradation

1\. Background

2\. General Description of Antidegradation

3\. 40 CFR 131.12 (a)(1) \`\`tier 1\'\'

a\. Tier 1 Implementation

4\. 40 CFR 131.12 (a)(2) \`\`tier 2\'\'

a\. Identification of \`\`High Quality\'\' Waters

b\. Tier 2 Implementation

i\. Triggers for tier 2 Review

ii\. \`\`Necessary\'\' Lowering of Water Quality

iii\. Identification of \`\`Important\'\' Social or Economic

Activities

iv\. Tier 2 and Identification of Waters under CWA Section 303(d)

v\. Achieving all cost-effective and reasonable best management

practices for nonpoint sources

5\. 40 CFR 131.12 (a)(3) \`\`tier 3\'\'

a\. Designating ONRWs

i\. Relationship of tier 3 to the Wild and Scenic Rivers Act

b\. Tier 3 Implementation

c\. Tier 2\\1/2\\

6\. 40 CFR 131.12 (a)(4) \`\`Thermal Discharges\'\'

E. Mixing Zones

1\. Background

2\. EPA Policy and Guidance on Mixing Zones

3\. State and Tribal Mixing Zone Policies

4\. Mixing Zone Requirements

5\. Mixing Analyses

6\. Narrative Criteria for Mixing Zones

7\. Mixing Zones for Bioaccumulative Pollutants

8\. Stream Design Flow Policies

F. Wetlands as Waters of the United States

G. Independent Application Policy

1\. Introduction

a\. Biological Assessments

b\. Toxicological Assessments

c\. Chemical Assessments

2\. Independent Application and Water Quality Assessments

a\. Independent Application

b\. Alternatives to Independent Application

3\. Independent Application and NPDES Permitting

a\. Independent Application

b\. Alternatives to Independent Application

IV\. Summary and Potential Program and Regulation Changes

V. Regulatory Assessment Requirements

A. Executive Order (E.O.) 12866, Regulatory Planning and Review

B. The Regulatory Flexibility Act (RFA) as Amended by the Small

Business Regulatory Enforcement Fairness Act (SBREFA) of 1996

C. Paperwork Reduction Act

I. Purpose and Objectives of This ANPRM

A. General Purpose and Vision

On February 14, 1998, the visionary \`\`Clean Water Action Plan\'\' was

announced by the Administrator of EPA and the Secretary of Agriculture.

The \`\`Clean Water Action Plan\'\' is a blueprint for restoring and

protecting the Nation\'s precious water resources. A key element of the

plan is advancement of the watershed approach to water quality

protection. EPA\'s belief is that refining designated uses and

implementing better more integrated water quality criteria to protect

the refined uses, two important themes of this ANPRM, are essential

steps in carrying out the blueprint presented. Revision of the water

quality standards regulation can be an essential component in

implementing the vision of the \`\`Clean Water Action Plan.\'\'

States, Tribes and EPA have developed functional water quality

standards programs under the current regulation and these programs have

provided the basis for significant water quality improvement in the

United States. Simply put, the current regulation is not broken.

Rather, with the renewed interest in watershed management combined with

improved methods for water quality assessment, a comprehensive

evaluation for the purpose of strengthening the regulation is

appropriate at this time. EPA and the public need to examine whether

changes in the regulation could enhance water quality management on a

watershed basis and focus resources on areas of greatest concern. A

review of the regulation will also complement similar outreach

discussions EPA is currently undertaking for the purposes of reviewing

the water quality planning and management and total maximum daily load

(TMDL) programs as well as aspects of the NPDES program. EPA is

committed to ensuring that these programs, combined, form an even

stronger integrated basis for water quality planning, priority setting

and implementation on a watershed basis.

In recent years there has been a rising level of scrutiny placed on

water quality standards and the State, Tribal and EPA decisions based

on water quality standards. The increased scrutiny comes from virtually

all parties affected by water quality-based decisions and is evidenced

by the growing tide of challenges to State standards, EPA policies and

guidance, and individual water quality-based decisions. Remaining water

quality problems in the U.S. are often difficult to assess, define and

solve. Once agreed upon, the solutions will be less conventional than

we are used to and may result in different regulatory approaches.

Examples of such problems include aquatic and riparian habitat

destruction from municipal and agricultural run-off and fish tissue

contamination from chemicals with many and diverse sources.

EPA believes that this scrutiny will continue and that an

evaluation of the water quality standards program and its regulatory

and policy underpinnings to identify where these program underpinnings

may need to be strengthened, clarified or revised is imperative. Our

task under the Clean Water Act is to ensure adequate water quality even

where it is difficult to do so. To accomplish this task, EPA envisions

a national water quality standards program in which: the best possible

information on whether designated uses are being attained and how to

attain and maintain them is available and used; water quality criteria

are selected from a wide-ranging menu of scientifically sound criteria

that can be tailored to each watershed; national norms of consistency

and flexibility in State and Tribal water quality standards are clear;

and innovative, cost-effective approaches are

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encouraged. To realize this vision, EPA believes that a structured

national debate is needed to identify a focused set of issues that may

ultimately lead to changes to the water quality standards regulation

and policy.

The ANPRM process allows EPA to begin this work by consulting with

all interested parties to find out what changes, if any, are necessary

and desirable, to make the water quality standards regulation more

responsive to current needs and to identify opportunities for further

clarifications of policy and guidance by EPA. In the fourteen years

since EPA last revised the water quality standards regulation,

interested parties have gained considerable experience in developing

and implementing water quality standards. This experience will provide

valuable information for review of these regulations.

The most significant shift in water quality management programs in

recent years has been the increased emphasis on the use of watershed

based programs. It is increasingly apparent that EPA, States, Tribes,

municipalities and the public share a common view that water quality

programs, including water quality standards, can be better tailored to

the characteristics, problems, risks and implementation tools available

in individual watersheds or basins with meaningful involvement of the

local communities. The water quality standards regulation should ensure

that States and Tribes have the flexibility to define the water quality

standards and hence the environmental objectives of a water body

according to the characteristics of the ecosystem and the needs of the

water\'s users within the bounds established under the CWA. The

regulation must allow the States and Tribes to tailor water body use

designations and criteria to protect these uses within individual

basins or watersheds based on the needs in the basin. The present use

of broad, jurisdiction-wide use classifications and lists of associated

chemical criteria may be at once too general and too narrow for some

waters, lacking the refinement necessary to tailor water quality

management actions to specific watersheds. This general approach

reflects the historical lack of information on specific basins or water

bodies and the need to ensure that all waters receive adequate

protection. Additionally, it should be made clear how much flexibility

States and Tribes have to adjust use designations as information

improves about whether a designated use or a higher use can be attained

and to reflect natural and human caused changes in water quality that

may have occurred. The challenge for EPA, States and Tribes is to

identify and use opportunities to refine use designations for waters

where it makes sense and better match the water quality criteria to the

refined use, thus making water quality standards more flexible. In

addition, to more effectively implement the standards, the criteria

that are used need to better integrate multiple stressors and their

cumulative impacts in order to more effectively protect designated

uses.

Significant scientific advancements in recent years have added to

the ability to assess environmental impacts and risks related to

changes in water quality. As they are further developed, new and

emerging sophisticated and integrated analytical tools such as

bioassessment, criteria for bioaccumulative chemicals, sediment quality

criteria and toxicity assessments will increasingly allow States,

Tribes, EPA and the public to characterize better the ecological

condition of water resources. At present, this improving capability,

used in a tailored watershed planning and management framework, can

enhance the ability of States and Tribes to characterize and protect

locally agreed upon goals for maintaining and protecting the chemical,

physical and biological integrity of individual basins. In the long

term, chemical, physical and biological assessment methods will

continue to improve. As they do, the water quality standards program

should be designed to accommodate effectively the new science. In the

meantime, progress should not be stalled by incomplete knowledge.

With the new science and assessment methodologies, however, come

new challenges for States and Tribes to identify the resources

necessary to make use of these advances. One of the main themes of this

ANPRM is the need for better data, and new types of data, in order to

support a more refined approach to water quality protection. EPA

recognizes, however, that efforts to obtain such data, and develop the

analytical capacity to integrate it into existing regulatory programs,

could encounter significant resource constraints in some States and

Tribes. EPA is well aware that in order for a new, data-intensive,

watershed-specific approach to succeed, it must be workable for the

States and Tribes that will have to implement it. EPA welcomes comments

regarding concerns over resource constraints and ideas for how to

address them.

The water quality standards program must protect the nation\'s

waters as envisioned in the CWA. It must establish requirements that

are necessary to attain and maintain healthy, sustainable ecosystems.

It must be flexible enough for States and Tribes to ensure that

standards are protecting water quality in a way that makes sense. EPA

seeks to avoid a program that results in costly requirements that have

little or no environmental benefit. Thus EPA intends to use its

experience and that of the States, Tribes, municipalities, the

regulated community, environmental groups and the general public in

implementing and utilizing water quality standards over the last

fourteen years, to evaluate the regulation and determine if changes are

needed to allow greater State, Tribal and local flexibility to develop

innovative, cost-effective ways to protect water quality.

EPA may determine through the ANPRM process that the concepts

described above can be better integrated into water quality management

decision making through development of new or revised policies and

guidance rather than revisions to the regulation. Because of this

possibility, EPA is reserving its decision whether to propose and

finalize revisions to the regulation. At minimum, EPA believes that any

revisions to the water quality standards regulation should result in a

regulation that can be used to render protective, tailored, site-

specific water quality-based decisions that bear reasonable compliance

costs for the regulated community, as well as reasonable implementation

costs for States, Tribes and EPA. At the same time, the regulation

should allow sufficient flexibility to States and Tribes, if they

choose, to implement water quality standards programs in a manner that

is no more burdensome than under the existing regulation.

B. Objectives

In publishing this ANPRM, EPA is beginning a review of the

regulation in a public forum in an attempt to identify possible

amendments to the regulation, and new guidance or policy that may be

needed to address three distinct objectives. They are: (1) to eliminate

any barriers and develop incentives to enhance State and Tribal

implementation of watershed-based water quality planning and

management; (2) to enhance State and Tribal capability to incorporate

current criteria and water quality assessment science into their water

quality standards programs, and; (3) to improve the regulation so that

it may be implemented more efficiently and effectively (including cost-

effectively). Meeting these three objectives, EPA believes, will

facilitate further water

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quality improvements locally and nationally. EPA urges commenters to

keep all three main objectives in mind when reviewing, analyzing and

commenting on this ANPRM.

II\. Introduction to Water Quality Standards

A. Statutory History

The first comprehensive legislation for water pollution control was

the Water Pollution Control Act of 1948 (Pub. L. 845, 80th Congress).

This law adopted principles of State-Federal cooperative program

development, limited federal enforcement authority, and limited federal

financial assistance. These principles were continued in the Federal

Water Pollution Control Act (Pub. L. 660, 84th Congress) in 1956 and in

the Water Quality Act of 1965. Under the 1965 Act, States were directed

to develop water quality standards establishing water quality goals for

interstate waters. By the early 1970\'s, all the States had adopted such

water quality standards. Since then, States have revised their

standards to reflect new scientific information, the impact on water

quality of economic development and the results of water quality

controls.

Due to enforcement complexities and other problems, an approach

based solely on water quality standards was deemed too weak to make a

difference. The purely water quality-based approach prior to 1972

lacked enforceable Federal mandates and standards, and a strong impetus

to implement plans for water quality improvement. The result was an

incomplete program that in Congress\' view needed strengthening. In the

Federal Water Pollution Control Act Amendments of 1972 (Pub. L. 92-500,

Clean Water Act or CWA), Congress established the National Pollutant

Discharge Elimination System (NPDES) whereby each point source

discharger to waters of the U.S. is required to obtain a discharge

permit. The 1972 Amendments required EPA to establish technology-based

effluent limitations that are to be incorporated into NPDES permits. In

addition, the amendments extended the water quality standards program

to intrastate waters and required NPDES permits to be consistent with

applicable State water quality standards. Thus, the CWA established

complementary technology-based and water quality-based approaches to

water pollution control. Now, after nearly 25 years of investment in

technology-based controls and some \$70 billion in sewage treatment

plant construction, attention is turning back to water quality

standards as a mechanism to make improvements in water quality beyond

those that have been achieved through technology-based controls.

Water quality standards serve as the foundation for the water-

quality based approach to pollution control and are a fundamental

component of watershed management. Water quality standards are State or

Tribal law or regulation that: define the water quality goals of a

water body, or segment thereof, by designating the use or uses to be

made of the water; set criteria necessary to protect the uses; and

protect water quality through antidegradation provisions. Although the

CWA gives EPA an important role in determining appropriate minimum

levels of protection and providing national oversight, it also gives

considerable flexibility and discretion to States and Tribes to design

their own programs and establish levels of protection above the

national minimum. States and Tribes adopt water quality standards to

protect public health or welfare, enhance the quality of water, and

serve the purposes of the Act. \`\`Serve the purposes of the Act\'\' (as

defined in Sections 101(a), 101(a)(2), and 303(c) of the Act) means

that water quality standards should: (1) include provisions for

restoring and maintaining chemical, physical, and biological integrity

of State and Tribal waters, (2) provide, wherever attainable, water

quality for the protection and propagation of fish, shellfish, and

wildlife and recreation in and on the water
(\`\`fishable/swimmable\'\'),

and (3) consider the use and value of State and Tribal waters for

public water supplies, propagation of fish and wildlife, recreation,

agricultural and industrial purposes, and navigation. See 40 CFR 131.2.

Section 303(c) of the CWA establishes the basis for the current

water quality standards program. Section 303(c):

1\. Defines water quality standards;

2\. Identifies acceptable beneficial uses: public water supply,

propagation of fish and wildlife, recreational purposes, agricultural

and industrial water supplies and navigation;

3\. Requires that State and Tribal standards protect public health

or welfare, enhance the quality of water and serve the purposes of the

Act;

4\. Requires that States and Tribes review their standards every

three years;

5\. Establishes the process for EPA review of State and Tribal

standards, including where necessary the promulgation of a superseding

Federal rule in cases where a State\'s or Tribe\'s standards are not

consistent with applicable requirements of the CWA or in situations

where the Administrator determines that Federal standards are necessary

to meet the requirements of the Act.

The decade of the 1970\'s saw State and EPA attention focus on

creating the infrastructure necessary to support the NPDES permit

program and development of technology-based effluent limitations. While

the water quality standards program continued, it was a low priority in

the overall CWA program. In the early 1980\'s, it began to be recognized

that greater attention to the water quality-based approach to pollution

control would be needed to effectively protect and enhance all of the

nation\'s waters.

The first statutory evidence of this was the enactment of a CWA

requirement that after December 29, 1984, no construction grant could

be awarded for projects that discharged into stream segments which had

not, at least once since December 1981, had their water quality

standards reviewed and revised or new standards adopted as appropriate

under Section 303(c). (Public Law 97-117, Section 24, \`\`Revised Water

Quality Standards.\'\') The efforts by the States to comply with this

one-time requirement essentially made the States\' water quality

standards current as of that date for segments with publicly-owned

treatment works (POTWs) discharging into them.

Additional impetus to the water quality standards program occurred

on February 4, 1987, when Congress enacted the Water Quality Act of

1987 (Pub. L. 100-4). Congressional impatience with the lack of

progress in State adoption of standards for toxics (which had been a

national program priority since the early 1980\'s) resulted in the 1987

adoption of new water quality standard provisions in the Water Quality

Act amendments. These amendments reflected Congress\' conclusion that

toxic pollutants in water are one of the most pressing water pollution

problems. One concern Congress had was that States were relying, for

the most part, on narrative criteria to control toxics (e.g., \`\`no

toxics in toxic amounts\'\'), which made development of effluent

limitations in permits difficult. To remedy this, Congress adopted

section 303(c)(2)(B), which essentially required development of numeric

criteria for those water body segments where toxic pollutants were

likely to adversely affect designated uses.

The 1987 Amendments gave new teeth to the control of toxic

pollutants. As Senator Mitchell put it, Section 303(c)(2)(B) requires

\`\`States to identify waters that do not meet water quality

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standards due to the discharge of toxic substances, to adopt numerical

criteria for the pollutants in such waters, and to establish effluent

limitations for individual discharges to such water bodies.\'\' (From

Senator Mitchell, 133 Cong. Rec. S733.) To assist States in complying

with Section 303(c)(2)(B), EPA issued program guidance in December 1988

and instituted an expanded program of training and technical

assistance.

Section 518 was another major addition in the 1987 Amendments to

the Act. This section extended participation in the water quality

standards and 401 certification programs to certain Indian Tribes. The

Act directed EPA to establish procedures by which a Tribe could

\`\`qualify for treatment as a State,\'\' at its option, for purposes of

administering the standards and 401 certification programs. The Act

also required EPA to create a mechanism to resolve disputes that might

develop when unreasonable consequences arise from a Tribe and a State

or another Tribe adopting different water quality standards on common

bodies of water.

Furthermore, with the 1987 Amendments, the Act explicitly

recognized EPA\'s antidegradation policy for the first time. The intent

of the antidegradation policy in EPA\'s regulation was and is to protect

existing uses and the level of water quality necessary to protect

existing uses and to provide a means for assessing activities that may

impact high quality waters and ruling on whether such projects could

proceed. Section 303(d)(4) of the Act requires that water quality

standards in those waters that meet or exceed levels necessary to

support designated uses \`\`may be revised only if such revision is

subject to and consistent with the antidegradation policy established

under this section.\'\'

B. Regulatory History

In the late 1960\'s and early 1970\'s the water quality standards

program was initiated and administered based on minimal guidance and

Federal policies\--many of which are still reflected in the water

quality standards program today.

EPA first promulgated a water quality standards regulation in 1975

(40 CFR 130.17, 40 FR 55334, November 28, 1975) as part of EPA\'s water

quality management regulations mandated under Section 303(e) of the

Act. As discussed earlier, the standards program had a relatively low

priority during this time. This was reflected in the minimal

requirements of the first Water Quality Standards Regulation. Few

requirements on designating water uses and procedures were included.

The Regulation was general, requiring \`\`appropriate\'\' water quality

criteria necessary to support designated uses and incorporating the

antidegradation policy. Toxic pollutants or any other specific criteria

were not mentioned.

Some States developed detailed water quality standards regulations

while others adopted only general provisions which proved to be of

limited use in the management of increasingly complex water quality

problems and created disparities in requirements on regulated entities.

The few water quality criteria that were adopted addressed a limited

number of pollutants and primarily described fundamental water quality

conditions (e.g., pH, temperature, dissolved oxygen and suspended

solids) or dealt with conventional pollutants.

In the late 1970s, EPA determined that existing State water quality

standards needed to be better developed. EPA moved to strengthen the

water quality program to complement the technology based controls. EPA

amended the Water Quality Standards Regulation to explicitly address

toxic criteria requirements in State standards and other legal and

programmatic issues. November 8, 1983 (54 FR 51400). This regulation is

more comprehensive than its predecessor and includes more specific

regulatory and procedural requirements. The 1983 regulation created the

concept of use attainability analysis, added detail on the adoption of

numeric criteria including authorization for site-specific criteria,

and listed specific procedural requirements and definitions not

included in the original 1975 regulation. The regulation specified the

roles of the States and EPA and the administrative requirements for

States in adopting and submitting their standards to EPA for review. It

also delineated the EPA requirements for review of State standards and

promulgation of federal standards.

The 1983 regulation provided States (and subsequently in 1991)

Tribes with the option of refining their use designation process by

allowing them to establish subcategories of uses, such as cold water

and warm water aquatic life designations. The 1983 regulation also

clarified that States (and subsequently Tribes) may adopt discretionary

policies affecting the implementation of standards, such as mixing

zones, low flows, and variances.

In support of the 1983 Regulation, EPA simultaneously issued

program guidance entitled Water Quality Standards Handbook (December,

1983). The Handbook provided guidance on the interpretation and

implementation of the Water Quality Standards Regulation. This document

also contained information on scientific and technical analyses that

are used in making decisions that would impact water quality standards.

EPA also developed the Technical Support Document for Water Quality-

Based Toxics Control (EPA 44/4-85-032, September, 1985) (TSD) which

provided additional guidance for implementing State water quality

standards. In 1991, EPA revised and expanded the TSD. (EPA 505/2-90-

001, March 1991). In 1994, EPA issued the Water Quality Standards

Handbook: Second Edition (EPA-823-B-94-006, August 1994).

To accelerate compliance with CWA section 303(c)(2)(B) (created by

the 1987 Water Quality Act), EPA started action in 1990 to promulgate

numeric water quality criteria for those States that had not adopted

sufficient water quality standards for toxic pollutants. The intent of

the rulemaking, known as the National Toxics Rule, was to strengthen

State water quality management programs by increasing the level of

protection afforded to aquatic life and human health through the

adoption of all available criteria for toxic pollutants listed under

307(a) of the CWA (priority pollutants) present or likely to be present

in State waters. This action culminated on December 22, 1992, with EPA

promulgating Federal water quality criteria for priority toxic

pollutants for 14 States and Territories (see 57 FR 60848).

Subsequent to the promulgation of criteria under the National

Toxics Rule, EPA altered its national policy on the expression of

aquatic life criteria for metals. On May 4, 1995 at 60 FR 22228, EPA

issued a stay of several metals criteria (expressed as total

recoverable metal) previously promulgated under the National Toxics

Rule for the protection of aquatic life. EPA simultaneously issued an

interim final rule that changed these metal criteria promulgated under

the National Toxics Rule from the total recoverable form to the

dissolved form.

The Water Quality Standards Regulation was amended in 1991 to

implement Section 518 of the Act to expand the standards program to

include Indian Tribes (56 FR 64893, December 12, 1991). EPA added 40

CFR 131.7 to describe the requirements of the issue dispute resolution

mechanism (to resolve unreasonable consequences that may arise between

a Tribe and a State or another Tribe when differing water quality

standards have been adopted for a common body of water) and 40 CFR

131.8 to establish the

\[\[Page 36747\]\]

procedures by which a Tribe applies for authorization to assume the

responsibilities of the water quality standards and section 401

certification programs.

Fourteen years since its last major revision, the water quality

standards regulation is undergoing review and potential revision in

light of experiences gained in its implementation by States, Tribes,

EPA and the public. The review is intended to reflect the changing

nature of the program and to identify specific changes that will

strengthen water quality protection and restoration, facilitate

watershed management initiatives, and incorporate evolving water

quality criteria and assessment science into water quality standards

programs. Based on the review and the comments expected on the ANPRM,

EPA may decide to revise parts of the regulation and/or change some of

its existing policies and guidance for the water quality standards

program.

Water quality standards are essential to a wide range of surface

water activities, including: (1) setting and revising water quality

goals for watersheds and/or individual water bodies, (2) monitoring

water quality to provide information upon which water quality-based

decisions will be made, (3) calculating total maximum daily loads

(TMDLs), waste load allocations (WLAs) for point sources of pollution,

and load allocations (LAs) for natural background and nonpoint sources

of pollution, (4) developing water quality management plans which

prescribe the regulatory, construction, and management activities

necessary to meet the water body goals, (5) calculating NPDES water

quality-based effluent limitations for point sources, in the absence of

TMDLs, WLAs, LAs, and/or water quality management plans, (6) preparing

various reports and lists that document the condition of the State\'s or

Tribe\'s water quality, and (7) developing, revising, and implementing

an effective section 319 management program which outlines the State\'s

or Tribe\'s control strategy for nonpoint sources of pollution.

Note: The term \`\`State\'\' as used in this Notice refers to the

fifty States, all Territories of the United States, and the District

of Columbia. The term \`\`Tribe\'\' or \`\`Tribal\'\' as used in this
Notice

generally refers to all Indian Tribes authorized to administer the

water quality standards. On occasion, the term \`\`Tribe\'\' or

\`\`Tribal\'\' refers to Indian Tribes that are eligible to seek

authorization to administer the water quality standards, but have

not yet secured such authorization. There are some parts of the law

and regulation where \`\`State\'\' is now interpreted to mean \`\`State
or

Tribe.\'\'

C. Water Quality Guidance for the Great Lakes System

On March 23, 1995, EPA published in the Federal Register its Water

Quality Guidance for the Great Lakes System (60 FR 15366, March 23,

1995\) (Great Lakes Guidance). The Guidance consists of water quality

criteria for 29 pollutants to protect aquatic life, wildlife, and human

health, and detailed methodologies to develop criteria for additional

pollutants; implementation procedures to develop more consistent,

enforceable water quality-based effluent limits in discharge permits,

as well as TMDLs of pollutants that can be allowed to reach the Great

Lakes and their tributaries from all sources; and antidegradation

policies and procedures.

Section 118(c)(2) of the Clean Water Act (CWA) (Pub. L. 92-500 as

amended by the Great Lakes Critical Programs Act of 1990 (CPA), Pub. L.

101-596, November 16, 1990) required EPA to publish proposed and final

water quality guidance on minimum water quality standards,

antidegradation policies, and implementation procedures for the Great

Lakes System. EPA responded to these requirements by initiating a

rulemaking, publishing the Proposed Water Quality Guidance for the

Great Lakes System (proposed Guidance) in the Federal Register on April

16, 1993 (58 FR 20802). EPA also published four subsequent documents in

the Federal Register identifying corrections and requesting comments on

additional related materials. EPA received over 26,500 pages of

comments, data, and information from over 6,000 commenters in response

to these documents and from meetings with members of the public.

After reviewing and analyzing the information in the proposal and

these comments, EPA developed and published the Great Lakes Guidance,

codified at 40 CFR Part 132. Part 132 contains six appendixes of

detailed methodologies, policies, and procedures. Detailed discussion

of the final Guidance is provided in \`\`Final Water Quality Guidance
for

the Great Lakes System: Supplementary Information Document\'\' (SID),

(EPA, 1995, 820-B-95-001) and in additional technical and supporting

documents which are available in the docket for the rulemaking. Copies

of the SID and other supporting documents are also available from EPA

in electronic format, or in printed form for a fee upon request.

Developing the Great Lakes Guidance was an enormous effort based on

extensive public comment and analysis on some of the same issues that

are addressed in this ANPRM. One principal difference between the

provisions in the Great Lakes Guidance and the regulation, policy and

guidance that is the subject of this ANPRM is that where the Great

Lakes Guidance addressed programs in the Great Lakes States only, this

ANPRM addresses the national water quality standards regulation and

program, and thus the programs of all States and Tribes with water

quality standards authority. Where the Great Lakes Guidance addressed

an issue or issue area that is also addressed in the ANPRM, that

analysis and conclusion may or may not be relevant to the discussion of

the national program. Where it is, today\'s ANPRM identifies the

specific relevant Great Lakes Guidance provisions in the specific issue

discussions. Many of the provisions in the Great Lakes Guidance were

developed to address the unique problems in the Great Lakes Basin that

stem from known contamination by bioaccumulative chemicals and the long

retention time of water in the Lakes. Commenters should keep in mind

that the Great Lakes provisions were derived for States that are in the

Great Lakes Basin in whole or part and should consider the uniqueness

of the Great Lakes Basin when evaluating Great Lakes Guidance

provisions for application outside of the Great Lakes Basin.

III\. Program Areas for Public Comment

A. Introduction

Entering its 33rd year, the water quality standards program has

begun to evolve from one with a narrow focus on establishing water body

uses and adopting chemical criteria for basic water quality

characteristics addressing the most obvious sources of pollution to a

more comprehensive program. In recent years the scientific community

has developed greater knowledge of the full range of stressors

adversely impacting surface waters. EPA believes the water quality

standards program should evolve to keep pace with expanding science to

address water quality problems in a more comprehensive way,

accommodating more specific and sophisticated water use

classifications, criteria for more pollutants, new forms of criteria

and companion ecological and health indicators, and closer integration

with other programs. At the same time, EPA realizes that such an

evolution could require a significant increase in analytical resources

from States, Tribes and the regulated community, and that changes to

the existing program must be structured in a way that is workable.

\[\[Page 36748\]\]

This is an appropriate time to begin a structured national debate

aimed at identifying the focused changes necessary to strengthen the

underpinnings of water quality standards and implementation. In the

fourteen years since the regulation was last revised, there have been

numerous scientific developments, statutory changes, court decisions,

and implementation issues affecting the water quality standards

program. The shift in program focus beyond just chemical contamination

to include ecosystem protection and watershed approaches necessitates

reexamining basic program concepts. In addition, there is an

opportunity to address possible barriers to effective water quality

improvements where it is determined that regulatory changes are

possible under existing law.

In recent years, EPA has heard from the States and Tribes as well

as the environmental and regulated communities regarding the necessity

and focus of a revision to the water quality standards regulation. As

indicated by the wide range of issues and options presented in this

advance notice, views of the different stakeholder groups often differ

considerably. Many stakeholders believe that a revised regulation is

needed for continued improvements in water quality protection. Others

believe changes are needed to allow more flexible, cost-effective

approaches by States and Tribes. Conversely, many stakeholders have

said that the regulation is sufficient and does not need to be

reviewed.

A key issue presented here relates to the degree of specificity

necessary should EPA revise the regulation. There are many who support

a more flexible regulation to allow States and Tribes to address new

and changing circumstances. Under a more flexible regulation, States

and Tribes could more easily tailor their programs to deal with

pressing water quality restoration and protection needs that are not

well addressed presently. Others support a regulation with more

specific regulatory requirements. The latter would promote a more

consistent minimal level of protection in State and Tribal water

quality standards, provide more clarity on standards issues, and serve

as a stronger tool in encouraging States and Tribes to take appropriate

restoration and protection actions. EPA urges commenters to consider

the appropriate balance between flexibility, national consistency, and

consistency within States and Tribes when commenting on any of the

ideas presented in this notice.

One of the outcomes of this ANPRM and follow-on actions can be

establishment of a clearer set of national minimum policies and

implementation procedures on which EPA will reliably and predictably

base its approval and disapproval decisions on State and Tribal water

quality standards submittals. EPA remains committed to making

consistent decisions from State to State and Tribe to Tribe and State

to Tribe to meet our obligation to ensure an appropriate level of

protection nationally and that the goals of the Act are achieved.

Clarifying these national norms will serve to better articulate the

norms of protection from State to State and Tribe to Tribe and State to

Tribe and also to clarify national norms of flexibility. Defining the

appropriate level of consistency, in turn, defines the appropriate

degree level of flexibility. In addition, establishing norms of

consistency and flexibility should help to resolve State or Tribal

differences with EPA on water quality standards early in the process,

before the approval/disapproval stage.

While the following discussion describes specific areas and issues

for public review, the public is welcome to comment on any aspect of

the water quality standards program. EPA emphasizes, however, that

publication of this Notice does not commit the Agency to proceeding

with a regulatory change. EPA has not decided whether it will, in fact,

propose regulatory amendments, and, if proposed, how extensive that

effort might be. This decision will be made after considering the

comments received and the need to address other priority activities as

well as any Congressional and Executive Branch directives. A potential

outcome of this public review may be additional guidance and/or

policies rather than regulatory changes.

EPA has not determined the next steps it will take after evaluation

of all the comments received on this ANPRM. It is likely that any

follow-on proposed rule to amend 40 CFR 131 would focus on a relatively

narrow set of issues and that many other issues could be resolved

through policy and guidance. EPA requests that commenters identify the

five to seven issues considered highest priority for possible

regulatory amendments. The summary section at the end of this notice

contains a brief summary of the potential changes to the water quality

standards regulation that are discussed and considered in this ANPRM.

The list of potential changes includes the full range of potential

changes to the regulation on which EPA is specifically requesting

comment. Each potential change to the regulation is discussed in detail

in the corresponding section of the ANPRM.

B. Uses

1\. Background

Section 131.10 of the current regulation describes States\' and

authorized Tribes\' responsibilities for designating and protecting

uses. The regulation requires that States and Tribes specify the water

uses to be achieved and protected; requires protection of downstream

uses; allows for sub-category and seasonal uses, for instance, to

differentiate between cold water and warm water fisheries; sets out

minimum attainability criteria; lists six factors of which at least one

must be satisfied to justify removal of designated uses which are not

existing uses; prohibits removal of existing uses; establishes a

mandatory upgrading of uses which are existing but not designated; and

establishes conditions and requirements for conducting use

attainability analyses.

These provisions make a distinction between existing and designated

uses and set out specific requirements to ensure protection of these

two broad use categories. Designated uses are defined as those uses

specified in water quality standards for each water body or segment

whether or not they are being attained. EPA interprets existing uses as

those uses actually attained in the water body on or after November 28,

1975 (the date of EPA\'s initial water quality standards regulation),

whether or not they are included in water quality standards. 40 CFR

131.3(e). Designated uses focus on the attainable condition while

existing uses focus on the past or present condition. Section 131.10

then links these two broad use categories in a manner which intends to

ensure that States and Tribes designate appropriate water uses,

reflecting both the existing and attainable uses of each water body.

For this discussion it is important to consider both the distinction

between and linkage of designated and existing uses.

It is in designating uses that States and Tribes establish the

environmental goals for their water resources, and it is in designating

uses that States and Tribes are allowed to evaluate the attainability

of those goals. Because water quality standards perform the dual

function of establishing water quality goals and ultimately serving as

the regulatory basis for water quality-based treatment controls and

strategies, typically, although not exclusively, via water quality

criteria protecting those uses, a State or Tribe often weighs the

environmental, social and economic

\[\[Page 36749\]\]

consequences of its decisions in designating uses. The regulation

allows the State or Tribe some flexibility in weighing these

considerations and adjusting these goals over time. Reaching a

conclusion on the uses that appropriately reflect the potential for a

water body, determining the attainability of those goals, and

appropriately evaluating the consequences of a designation, however,

can be a difficult and controversial task. Appropriate application of

this process involves a balancing of environmental, scientific,

technical, and economic and social considerations as well as public

opinion and is therefore one of the most challenging areas of the

current regulation.

To direct this decision making-process, the regulation establishes

requirements that must be followed when designating uses or concluding

that attaining a use is infeasible. When performing this attainability

analysis, a State or Tribe considers physical, chemical, biological and

economic factors that may limit the potential for achieving the goal

use.

EPA\'s current water quality regulation effectively establishes a

\`\`rebuttable presumption\'\' that \`\`fishable/swimmable\'\' uses are

attainable and therefore should apply to a water body unless it is

affirmatively demonstrated that such uses are not attainable. EPA

believes that the rebuttable presumption policy reflected in these

regulations is an essential foundation for effective implementation of

the Clean Water Act as a whole. The \`\`use\'\' of a water body is the
most

fundamental articulation of its role in the aquatic and human

environments, and all of the water quality protections established by

the CWA follow from the water\'s designated use. This approach preserves

States\' and Tribes\' paramount role in establishing water quality

standards, in this instance, in weighing any available evidence

regarding the attainable uses of a particular water body. The

rebuttable presumption approach does not restrict the discretion that

States and Tribes have to determine that \`\`fishable/swimmable\'\' uses

are not, in fact, attainable in a particular case. Rather, if the water

quality goals articulated by Congress are not to be met in a particular

water body, the regulations simply require that such a determination be

based upon a credible, \`\`structured scientific assessment\'\' of use

attainability.

Because there is a presumption that the uses specified in sections

101(a)(2) and 303(c) of the Clean Water Act are attainable (protection

and propagation of fish, shellfish and wildlife and recreation in and

on the water \[101(a)(2)\]; public water supplies, propagation of fish

and wildlife, recreational purposes, agricultural purposes, and

navigation \[303(c)(2)(A)\]), the criteria for overcoming that

presumption are carefully circumscribed. The economic use removal test,

for example, requires a showing that the cost of compliance with the

use(s) would result in \`\`substantial and widespread economic and
social

impact.\'\' This is a high threshold to ensure that the interim goals of

section 101(a)(2) and the section 303(c) uses are not abandoned without

appropriate cause.

The general construction of the Sec. 131.10 requirements for

designating uses, supplemented with specific Agency guidance, has

worked well in most situations over the last 14 years, and the use

designation process is well established in State and Tribal water

quality standards programs. There are, however, a number of new issues

that have arisen since the 1983 regulation was promulgated. Often these

new issues are associated with site-specific decision-making, and EPA

expects the trend toward site-specific application of water quality

standards will accelerate as States and Tribes begin implementing

watershed protection programs, using field biological information to

more precisely describe aquatic communities to be protected or

restored, and applying new watershed or ecosystem-specific approaches

to criteria development. As explained in the \`\`Objectives\'\'
discussion

in this document, one of the principal reasons for this notice is to

determine whether or not the current regulation is sufficiently

flexible to accommodate an expected shift in program emphasis beyond

chemical contaminants to ecosystem protection and watershed approaches

that will necessarily place greater emphasis on integrated assessments

of both chemical and non-chemical stressors and watershed-specific

decision-making.

While it is important to identify potential barriers to needed

flexibility, commenters should identify, as well, any changes or

clarification that may be needed to ensure that an appropriate level of

national consistency is maintained across and within all jurisdictions.

In this section of the notice, EPA seeks comment on the following

issues: (1) refined designated uses with more focus on watersheds and

ecosystems, (2) existing uses, (3) attainability and removal of

designated uses, and (4) alternatives to removal of designated uses.

2\. Refined Designated Uses

The current regulation at 40 CFR 131.10(a), based on section 303 of

the CWA, requires that States and authorized Tribes specify appropriate

water uses to be achieved and protected, taking into consideration the

use and value of water for public water supplies, protection and

propagation of fish, shellfish and wildlife, recreation in and on the

water, agricultural, industrial, and other purposes including

navigation. The regulation also allows, but does not require, States

and Tribes to identify more specific sub-categories of these general

use categories.

Over the years, States and Tribes have created many different use

classification systems ranging from a straightforward replication of

uses specifically listed in section 303 of the Act to more complex

systems that express designated uses in very specific terms or

establish sub-classifications which identify different levels of

protection. For example, some States simply specify \`\`water supply\'\'
as

a use classification applicable throughout the State while others may

identify several specific sub-categories related to the quality of the

raw water supply and anticipated treatment requirements. Similarly,

some States designate general \`\`aquatic life\'\' uses while others
list a

variety of sub-categories based on a range of aquatic community types

which may include descriptions of core aquatic species representative

of each sub-category. Although a variety of approaches have evolved and

become established in State and Tribal programs, the current regulation

is not specific about the level of precision States or Tribes must

achieve in designating uses.

There are advantages and drawbacks for either the general or

specific use classification systems and it is not clear that either is

necessarily superior in ensuring full protection of State or Tribal

water quality. There is, however, a need for the use designation

process, whether implementing a general or specific classification

system, to clearly articulate and differentiate intended levels of

protection with enough specificity so that decision-makers can

appropriately develop and implement the standards on a site-or

watershed-specific basis and so that the public can understand,

identify with, and influence the goals set for waters they care about.

Lack of precision in uses and criteria assigned to protect those

uses can inadvertently result in either a lesser or greater level of

protection than was actually intended when the water quality standards

were adopted. Although the designated use specificity

\[\[Page 36750\]\]

issue may apply to any of the Section 303 general use categories, it

may be most relevant for aquatic life uses. Aquatic communities can

vary significantly from water body-to-water body. As noted above,

however, State and Tribal use classifications generally do not reflect

the variability among aquatic community types and may list, instead,

very general descriptions such as \`\`aquatic life\'\' as the designated

use. Where this is the case, it is possible that measurable changes in

aquatic community composition or production could occur at a specific

site and still satisfy the definition of \`\`aquatic life,\'\' unless

somewhere in its process the State or Tribe has documented information

about its specific intent in applying the \`\`aquatic life\'\'

classification to each water body. For example, an activity that causes

the discharge of sediment, altering the physical habitat in the

receiving water body, could result in a measurable change in aquatic

community structure and function (e.g., the types of aquatic species

found in that segment). Yet, that activity may arguably satisfy a

general \`\`aquatic life\'\' use protection requirement simply because
of a

lack of specificity in the regulatory description of that designated

use. In this case, lack of precision in the designation or description

of the use could result in under protection of the resource, unless

somewhere in the State or Tribal process an intended level of

protection is specified.

Alternatively, lack of precision in uses and assigned criteria

could result in standards that are over protective, resulting in

application of unnecessary control requirements. In assigning criteria

to protect general use classifications, a State or Tribe must ensure

that the criteria are sufficiently protective to safeguard the full

range of waters in the State or Tribe (i.e., criteria would be based on

the most sensitive use). While this approach will result in full

protection of all State or Tribal waters, the approach has been

challenged, especially for aquatic life uses, where evidence suggests

that the general use and criteria will require controls more stringent

than needed to protect either the existing or potential aquatic

community for a specific water body. Although EPA supports broad

application of statewide or tribe-wide criteria to ensure that

sensitive uses are protected where site-specific information is

lacking, the Agency\'s current thinking is that there is a growing need

to more precisely tailor use descriptions and criteria to match site-

specific conditions, ensuring that uses and criteria provide an

appropriate level of protection which, to the extent possible, is

neither over nor under protective. This concept was reflected in the

Agency\'s 1994 Combined Sewer Overflow Policy (59 FR 18688).

The level of protection issue is one of both use and criteria. To

have a meaningful effect, a more precise use description must be

accompanied by more focused criteria, appropriately tailored to the

refined use description. EPA recognizes that, at present, national or

statewide or tribe-wide criteria generally are not sufficiently precise

to distinguish among all of the various sub-categories of uses. As

water quality standards issues become more watershed-specific or site-

specific, however, the trend will very likely be toward more specific

use descriptions and; because the essential purpose of the criteria is

to describe, evaluate attainment of, and protect the designated use;

more site-specific criteria development.

A potential constraint for refining the aquatic life uses would be

the resource commitment often associated with developing a

comprehensive biological database. Because of the resource constraints,

it may be difficult for a State or Tribe to develop designated uses (or

use descriptions) for each segment that include a detailed biological

description of the aquatic community to be protected. Simply from a

practical standpoint, it may be more workable to reserve such precise

determinations for watershed-specific decision-making. Therefore, in

highlighting the issue of greater specificity, EPA is suggesting that

one, but perhaps not the only, way to resolve this issue is to mandate

much greater specificity in a State or Tribal use classification

structure.

Obviously, there is a need for designated use descriptions in State

and Tribal regulation to be defined, at a minimum, with sufficient

specificity to ensure existing and potential uses will be protected

and/or attained. The difficulty is in striking a balance between

specificity sufficient to ensure uses are appropriately protected and

flexibility needed to allow efficient widespread application of a

classification system to all State or Tribal waters. A question has

been raised about, and EPA is considering, whether or not the current

regulation and guidance provide the framework needed to strike the

appropriate balance and the guidance on when and how to refine uses.

Aquatic Life

An issue related to the manner in which States and Tribes define

designated aquatic life uses is the occasional confusion expressed

between the actual intent of the CWA section 101(a)(2) interim goals

and the \`\`fishable/swimmable\'\' short hand expression often used to

describe those interim goals. EPA acknowledges that the phrase

\`\`fishable/swimmable\'\' does not fully describe the intent and scope
of

the CWA section 101(a)(2) interim goals. The confusion over the

expression \`\`fishable\'\' often surfaces where there is an action
aimed

at removing an aquatic life use from a particular water body where

there are no sport or commercial fisheries. In these instances, an

argument is often made that the water body does not meet the

\`\`fishable\'\' intent of the section 101(a)(2) interim goals because
the

water body naturally supports only \`\`minnows\'\' and/or aquatic

invertebrates. EPA believes this is an unacceptable argument for

removing an aquatic life designated use or excluding an aquatic life

designated use. As explained in EPA\'s Questions and Answers on

Antidegradation (USEPA, 1985, p. 3), the Agency considers the

protection afforded by standards to focus on an appropriately

representative aquatic community whether or not that community includes

sport or commercial fish:

The fact that sport or commercial fish are not present does not

mean that the water may not be supporting an aquatic life protection

function. An existing aquatic community composed entirely of

invertebrates and plants, such as may be found in a pristine

tributary alpine stream, should be protected whether or not such a

stream supports a fishery. Even though the shorthand expression

\`\`fishable/swimmable\'\' is often used, the actual objective of the

Act is to restore the chemical, physical and biological integrity of

our Nation\'s waters (Section 101(a)). The term \`\`aquatic life\'\'

would more accurately reflect the protection of the aquatic

community that was intended in Section 101(a)(2) of the Act.

Thus, EPA\'s current interpretation of the regulation means that the

Agency will not approve State or Tribal action to exclude aquatic life

protection based on a conclusion that a water body does not support a

\`\`fishery\'\', implying a sport or commercial fishery. EPA\'s current

thinking is that it would improve the regulatory text to reflect this

interpretation explicitly.

More specific to this discussion of refined designated uses is the

question of whether or not the Agency should mandate that a minimum

\`\`aquatic life\'\' use sub-category or sub-categories be included in
all

State or Tribal designated use classification systems to ensure

appropriate protection of waters

\[\[Page 36751\]\]

which do not support commercial or sport fisheries (or any fish).

Refined Designated Uses and Use Attainability Requirements

There is one additional issue related to the refined designated use

discussion that should be addressed. A question has been raised about

the applicability of the use attainability requirements when

establishing refined designated uses (with particular emphasis of

aquatic life uses). The question raised is: since refined designated

uses may be less inclusive than broad designations, will EPA consider

development of a more refined use description to be a change in use

subject to the use attainability requirements? Under current

regulation, the combination of a new use sub-category and less

stringent criteria triggers the use attainability requirements in

Sec. 131.10 of the Federal regulation (see Sec. 131.10(j)(2)). However,

it is possible that under certain circumstances, this requirement could

be modified.

Such a modification would focus on the kind of information that

should accompany any refined use classification based on a more precise

biological description, whether or not formal use attainability

assessment requirements apply. Essentially, there are two issues to be

addressed: (1) does the refined description of the aquatic community

reflect the reference condition (i.e., natural states) for the kinds of

waters to which the new classification is to be applied? and (2) are

any newly proposed criteria scientifically defensible? These are basic

questions which would have to be addressed whether or not the use

attainability requirements were invoked. As a result, a proposal to

refine use categories will have to be accompanied by a rationale

explaining how it was determined that the proposed biological

description appropriately reflects the potential for waters to which

the new sub-classification is to be applied. If warranted, this refined

description can then serve as the basis for deriving defensible and

appropriate criteria specific to the new sub-classification.

Request for Comment Refining Use Designations

EPA seeks comment on the following questions:

1\. The current regulation is not specific about the level of

precision States or Tribes must achieve in designating uses. The

regulation allows for subcategories of uses, but does not mandate such

an approach. Should the regulation be revised to promote or require

greater specificity in designated uses, particularly for aquatic life

uses, to support watershed-specific decision-making such as is

anticipated in implementing watershed or place-based initiatives?

2\. Where a State or Tribe utilizes broadly-defined designated uses,

could the desired level of specificity be adequately addressed in State

or Tribal standards that clearly articulate the intent of the

designated uses as they would apply to specific waters of the State or

Tribe?

3\. If EPA were to specify a required level of precision in

establishing use categories, what factors should be considered in

prescribing a level of specificity? That is, what factors should be

considered in striking a balance between specificity sufficient to

ensure uses are afforded an appropriate level of protection and

flexibility/efficiency needed to allow widespread application of the

classification system?

4\. At a minimum, should the regulation require that State and

Tribal aquatic life use categories include a sub-category or sub-

categories that may be assigned to protect aquatic communities that do

not include a \`\`fishery\'\'? Alternatively, should the regulation

explicitly reflect EPA\'s current interpretation of the regulations to

the effect that State and Tribal aquatic life classification systems

protect a range of aquatic communities whether or not there are sport

or commercial fish (or any fish) present?

5\. Should the use attainability requirements in 131.10(j)(2) be

modified to recognize situations where scientifically defensible less

stringent criteria may be appropriate for refined uses which reflect

the reference condition for particular waters?

3\. Existing Uses

a\. Protection of Existing Uses. The requirement to protect existing

uses is addressed in two places in the current regulation\--Section

131.10, designation of uses and Section 131.12, antidegradation. (see

discussion of antidegradation, \`\`tier 1\'\', in section III.D of this

document) As discussed in the background section above, the regulation

defines \`\`existing uses\'\' as \`\`those uses actually attained in the

water body on or after November 28, 1975, whether or not they are

included in the water quality standards.\'\' (40 CFR 131.3(e)) As a

result, the focus of existing uses, is on the past or present condition

of the water body. Furthermore, by establishing requirements

prohibiting the removal of existing uses and ensuring those uses will

be appropriately recognized in State and Tribal water quality

standards, the current regulation ensures that the better of the past

or present condition, at a minimum, will be maintained and protected.

Determining whether or not an existing use has occurred in the past or

is currently in place is not always a straightforward task, however,

and over the years, a number of questions have been raised about

exactly what the \`\`existing use\'\' provisions in 131.10 require.
These

questions generally fall into two categories: (1) what is the link

between existing uses and the State or Tribal use classification

system? and (2) what is the relationship between existing uses,

existing water quality and potential uses, i.e. uses that may be

attainable in the water body whether or not those uses are presently

designated for the water body or are presently being attained?

The first question addresses the relationship between the existing

use protection provisions in Section 131.10 and State or Tribal use

classification systems. There appears to be some confusion on this

point. The confusion seems to center on what may appear to be

conflicting mandates\--protect what is there and allow no further

erosion of water quality, and appropriately designate the existing use

in regulation using the established classification system. The existing

use definition and the requirement that existing uses be protected

suggests to some that the description of existing uses is constrained

by the way in which a State or Tribe has described its designated uses

in its classification system. That is, they argue that an existing use,

to be adequately protected, needs to fit into one of the categories or

sub-categories established in State or Tribal regulation, and as a

result, a decision about whether or not a use is \`\`existing\'\' is

likewise constrained by the use descriptions and criteria established

in that classification system.

For purposes of Section 131.10, this is generally the case. Again,

this Section of the Federal regulation establishes two requirements

with respect to existing use protection: (1) a prohibition against

removal of a designated use where that use is determined to be an

existing use, and (2) a requirement that existing uses be protected by

State or Tribal regulation. To ensure a workable process, EPA

interprets Section 131.10 as necessarily recognizing a linkage between

the existing use protection provisions and the established State or

Tribal use classification system. This interpretation of the regulatory

framework, however, also presumes a responsibility on the part of a

State or Tribe to establish a classification system that is

sufficiently flexible and/or

\[\[Page 36752\]\]

encompassing to assure an appropriate level of protection for the

anticipated range of existing uses (see discussion on refined

designated uses in this chapter).

As explained earlier in the discussion on refined designated uses,

a variety of use classification systems has evolved and become

established in State and Tribal programs. Although there are likely

some advantages to a more refined use classification system when it

comes to protecting existing uses (more precise categories in which to

fit the existing use), such a system may not be necessary as long as

the State or Tribal standards clearly articulate the intended and

appropriate level of protection for existing uses (again, see

discussion of refined designated uses). The following example

illustrates the point. An acid bog is a water body type which may be

fairly widespread but which, as a classification type, may not appear

in many State or Tribal standards. Where the aquatic characteristics of

an acid bog are discovered to constitute an existing use, a State or

Tribe could: (1) establish a classification type and criteria for acid

bogs to ensure appropriate protection by way of a specific designation,

or (2) classify the bog within the existing, general classification

system, e.g., warm water aquatic life, and adopt any needed site-

specific criteria to ensure the existing nature and quality of this

specific water resource is protected. Either approach can result in an

appropriate level of protection and there may not be a need for States

or Tribes to include an \`\`acid bog\'\' water body type in their

classification system. Under either approach the standards must

articulate clearly the intended and appropriate level of protection,

ensuring protection of the existing use.

It is also important to remember that the existing use provisions

in both Secs. 131.10 and 131.12 must be considered together. The

classification requirements in Sec. 131.10 ensure that all existing

uses will be recognized and protected through appropriate

classification of those water bodies in the standards (and/or

application of appropriate site-specific criteria where the existing

classification system is broadly constructed). The antidegradation-

based existing use protection provision guarantees that individual

activities on individual water bodies will be examined to ensure those

activities will not eliminate existing uses, whether or not those uses

are currently recognized in the State or Tribal standards. The

antidegradation provisions, through the general requirement that

existing uses be protected, ensure immediate protection from specific

activities which may threaten the existing use, and the classification

requirements ensure recognition and longer-term protection from any

present or future stressors through specific designation in the

standards. Both these provisions apply and should not be considered in

isolation. Together they constitute the existing use protection

requirements, ensuring the existing uses and water quality to support

those uses are maintained and protected.

The second question addresses the relationship between existing

uses, existing water quality and potential uses. The Agency\'s guidance,

Questions and Answers on Antidegradation, August, 1985 (Notice of

Availability, 50 FR 34546, August 26, 1985 \[included as appendices to

Water Quality Standards Handbook, cited above\]) addresses this issue,

in part. The answer to \`\`question 7\'\' states: \`\`an existing use
can be

established by demonstrating that fishing, swimming, or other uses have

actually occurred since November 28, 1975, or that the water quality is

suitable to allow such uses to occur (unless there are physical

problems which prevent the use regardless of water quality).\'\' Using
an

example of a healthy shellfish community which is not currently being

harvested, the answer goes on to explain that the existence of a use

(past or present) is not dependent solely upon a demonstration that the

use is being satisfied in a functional sense (i.e., in this case, the

shellfish harvested). In this example, \`\`shellfish harvesting\'\' is

considered an existing use, even though there is presently no

harvesting underway, because the water quality and habitat support a

healthy shellfish community suitable for harvesting. The answer further

explains that to assume otherwise \`\`\* \* \*would be to say that the
only

time an aquatic protection use \`exists\' is if someone succeeds in

catching fish.\'\' As illustrated in this example, the existing use

question must address both the current or past functional use and the

current or past (since November 28, 1975) water quality, and the intent

of the regulation is to ensure the existing use and the water quality

necessary to support that use are maintained and protected. Thus, in

this example, the shellfish harvesting use is to be protected by

designated uses in water quality standards.

The shellfish example is a good one in that it clearly illustrates

EPA\'s position that an existing use finding can be made either where

the use is or has been \`\`actually attained\'\' or where the water
quality

necessary to support the use is in place even if the use, itself, is

not currently established, as long as other site-specific factors, for

example physical problems like flow or substrate, would not, despite

the suitable water quality, prevent attainment of the use. The \`\`other

factors\'\' caution is important in understanding EPA\'s position on

existing uses. In making an existing use determination, there is a link

between the use and water quality. To be considered an existing use,

the use must have been actually attained in the past, is now attained

or water quality is sufficient to support the use. However, for some

sites, water quality, alone, may be an insufficient basis for making an

existing use finding if there are other factors that would prohibit the

use from taking place regardless of the quality of the water at a site.

In the shellfish example, the necessary water quality is present, and

there are no obvious limiting factors which would prohibit present or

future shellfish harvesting.

Although this example is useful in illustrating important

principles in implementing existing use protection requirements, it is

a rather straightforward example. An appropriate resolution of the

existing/designated use issue may be somewhat less clear-cut where

either the existing water quality or the existing use is marginal

(i.e., it is difficult to determine whether or not the use is actually

attained, or whether or not there are factors, other than water

quality, that could prohibit the use). It is in addressing these

situations that questions have been raised about what the current

regulation requires. A principal difficulty in addressing these

questions may lie in resolving the linkage between the present and past

conditions protected by the \`\`existing uses\'\' provisions and the

attainable or potential condition protected by \`\`designated uses\'\'

provisions. It may be useful to evaluate this issue by considering the

link between existing and designated uses established in the current

regulation.

Obviously, any decision about whether or not a use is an \`\`existing

use\'\' must be a water body-specific determination. The existing use

determination is, therefore, site-specific, and decisions should

consider water quality and other limiting factors such as the physical

habitat specific to a particular water body. A few examples may help

illustrate the issue. A somewhat common existing use question applies

to primary contact recreation: if a few people on a few occasions

\`\`swim\'\' in a water body that does not have the quality or physical

characteristics to support swimming, is this an existing use, even if

the water body is posted \`\`no swimming\'\' due to

\[\[Page 36753\]\]

bacterial contamination and lacks the physical features to actually

support swimming? The straightforward answer to this question is that

\`\`swimming\'\' is not an existing use because the present (or past)

condition does not support that use. This conclusion is based on the

very limited actual \`\`use\'\' and, more importantly, the lack of
suitable

water quality and physical characteristics that would support a

recreational swimming use now or in the future (as determined by the

water quality requirements and recreational swimming considerations,

including safety considerations, in the State or Tribal classification

system for primary contact recreation).

A question has been raised as to how to interpret the regulation in

the context of this example. One could determine that because the water

body is not suitable for swimming, and has not been since 1975, primary

contact recreation is not an existing use. Alternatively, one could

determine primary contact recreation to be an existing use because the

water body was actually used for swimming, even though the use was

occasional and water quality and physical characteristics were not

acceptable to support such a use. EPA believes the first alternative is

the better interpretation of Agency regulations and guidance in this

example, because the use is not established and the water quality and

other factors would appear to prohibit actually attaining a

recreational swimming use.

Stating that this is an appropriate interpretation of the

regulation means that EPA would not object if a State or Tribe reached

a conclusion, in a similar case, that this was not an existing use. As

noted above, however, existing use decisions are very site-specific,

and it is possible that, on a specific water body under similar

circumstances, a different conclusion could be reached by a State or

Tribe based on public comment at a hearing and a decision to take a

protective approach to the incidental use for that specific resource.

The Federal requirements do not prohibit a State or Tribe from taking a

more protective approach than would be required by the water quality

standards regulation.

Although, in the above example, a State or Tribe could conclude

that primary contact recreation is not an existing use, it may well be

an attainable use that must be protected as a designated use by the

State\'s or Tribe\'s water quality standards. This finding would depend

on whether the physical condition of the water body is suitable for

swimming and whether the water quality problems limiting the use are

controllable. (See 40 CFR 131.10(j) and discussion on use attainability

analysis below). The point is that, although the existing use

provisions most directly address past or present conditions, decisions

about existing uses generally are not made in isolation. With respect

to uses contained in CWA Section 101(a)(2), the regulation links

existing and designated uses, and it may be useful to view these

provisions as a continuum in examining the broader question of use

protection.

Some States and Tribes have recognized that continuum in developing

use attainability guidance for recreational uses which includes

questions about the actual use, existing water quality, water quality

potential, recreational facilities, location, safety considerations,

physical conditions of the water body, and access

Note: access here means restricted access, as in fenced

property; access is not intended to suggest the \`\`remoteness\'\' of

the water body; in EPA\'s view, remoteness is not a valid basis for

an attainability decision on recreation.

When all of these factors are considered, the adopted water quality

standards are consistent with both the existing and designated use

provisions. For example, suppose a city has created a greenway along a

stream that receives wastewater effluent upstream of the greenway and

has posted \`\`no swimming\'\' signs. The greenway attracts children

leading to the inevitable \`\`unauthorized\'\' swimming. If the physical

condition of the stream is suitable for swimming, the swimming occurs

on a frequent basis and the greenway provides recreational facilities

and access, the only factor limiting the use may be a water quality

problem that in the judgement of the State or Tribe can be controlled

to achieve the primary contact use. The linkage between existing and

designated uses encourages the evaluation of this full suite of factors

in making a decision about whether or not primary contact recreation

should be protected.

A similar existing use question is often raised for aquatic life

uses where the existing aquatic community is impaired as a result of

marginal water quality. A common example in the western part of the

country is a mountain stream impaired by historic hard rock mining

(with the impacts occurring well before November 28, 1975). Although

the physical condition of the stream may represent ideal trout habitat,

the trout population may be severely limited, in poor condition or

absent as a result of the toxic effects of metals. In its

classification system, however, a State or Tribe may describe and

designate this type of stream as a \`\`salmonid spawning\'\' use based
on

its physical habitat and potential. For streams such as these, where a

few adult trout are present but there is no evidence of younger age

classes, the question is asked\--is this an existing \`\`salmonid

spawning\'\' use?

Again, the appropriate answer, based on EPA regulations and

guidance, is that this is not an existing use (although it may

nonetheless be an appropriate designated use if it has the potential to

support salmonid spawning). The current use, matching the

classification description, is absent, and the limiting water quality

problems have been in existence prior to November 28, 1975. (This does

not mean, necessarily, there is not some existing aquatic life use

which would then serve as the regulatory \`\`floor\'\' for this water
body;

see the \`\`limited\'\' aquatic life use discussion in the use

attainability analysis discussion in this section below and the \`\`tier

1\'\' discussion in the antidegradation section, III. D) As in the

\`\`swimming\'\' example, however, there can be a gradation of
conditions,

and occasionally it may be difficult to draw a bright line and

conclude, with confidence, that this is where the existing use begins.

In situations similar to this impaired stream example, where the

existing water quality problems are considered controllable by the

State or Tribe, arguments have been made on both sides of the existing

use issue: the salmonid spawning use is not existing, or the salmonid

spawning use is in place, albeit currently at an impaired level.

Disputes about the correct interpretation of Agency guidance become

even more difficult to resolve where the existing impacts to water

quality are not as great as those in the above example. Often streams

impacted by historical mining, such as the one described above, are

headwater streams. As the water moves downstream, clean water

tributaries reduce the effect of the metals contamination, and fish, in

number, begin to move into these \`\`improved\'\' waters. Nevertheless,

many such streams would be considered impaired when compared to

unaffected, similar waters (reference streams). And, despite supporting

\`\`fairly good numbers\'\' of trout, the existing water quality in such

streams often exceeds the chronic and, occasionally, acute standards

for metals. In situations such as these, States and Tribes have had

difficulty in reaching conclusions about whether or not an existing

use, matching the classification, is in place. Because States and

Tribes may evaluate existing uses when they are designating uses,

threshold existing use

\[\[Page 36754\]\]

determinations may lead to questions about the potential for the water

body and the appropriate designated uses for it.

EPA\'s current interpretation is that the existing use should be

identified either where the use has taken place or the water quality

sufficient to support the use has existed since November 28, 1975, or

both. That is to say, State and Tribal existing use decisions can be

based on a finding that the use, as defined in the classification

system, and/or the water quality needed to support the use is in place

(and there are no other factors that would prohibit actually attaining

the use). This interpretation does not fully address the issue of

partially impaired uses. Thus, a fuller explanation may be needed in

the regulation or policy of how that interpretation is applied where

the use or the water quality may be somewhat impaired. EPA is

considering whether changes to the regulation or additional guidance is

needed to explain the Agency\'s position and to offer direction in

making such determinations.

Request for Comment on Existing Uses

EPA seeks comment on the following questions:

1\. Does EPA need to further clarify the existing use protection

provisions in Sec. 131.10, more clearly explaining that existing uses

are defined by the uses made of water bodies and existing water

quality, where that quality is or was sufficient to allow the use to

occur (and there are no other limiting factors)? If so, will the

clarification require a regulatory amendment or can the needed

clarification be accomplished in Agency policy or guidance?

2\. Does EPA need to expand its guidance to explain how the current

regulation addresses existing use decisions where there is some

semblance of a use even though the water quality is insufficient to

support the use in, for example a safe or healthful manner? Should this

additional guidance clarify the linkage between existing and designated

uses?

3\. Should the regulatory definition of \`\`existing use\'\' at 40 CFR

131.3(e) be modified? If so, how?

4\. Use Attainability.

a\. Attainability of Uses. States and Tribes may remove a designated

use, that is not an existing use, if they can demonstrate that

attaining the designated use is infeasible. (40 CFR 131.10(g)) The

current regulation identifies the factors that must be considered in

making such a demonstration. As explained in the regulation, existing

uses, by definition, are attainable and must be protected by designated

uses in water quality standards (40 CFR 131.10(h)(1), 131.10(i) and

131.12(a)(1)). Further, at a minimum, uses are considered attainable if

they can be achieved by implementing effluent limits required under

Sections 301(b) and 306 of the Clean Water Act (Act) and by

implementing cost-effective and reasonable best management practices

(BMPs) for nonpoint source control. (40 CFR 131.10(h)(2)).

These existing uses, technology and BMP provisions establish the

basic regulatory threshold test for what the attainable use of a water

body is and thus what the minimum use designation for the particular

water body must be. Where either the use is existing or the use can be

attained through implementation of Clean Water Act technology

requirements and/or implementation of applicable State requirements

regarding BMPs for nonpoint source control, 40 CFR 131.10(h)

establishes that the use is attainable and must be designated. Once a

use is designated, it is presumed to be attainable and may not be

removed (downgraded) unless the State or Tribe can demonstrate that

attaining the designated use is not feasible based on one of the six

use removal criteria (40 CFR 131.10(g)). Therefore, uses are considered

attainable if: (1) the use is existing; (2) the use can be attained

through application of CWA technology requirements and/or State or

Tribe required BMPs; or, (3) none of the use removal criteria is

satisfied. EPA has in the past recommended that these use removal

criteria referenced under number 3 above, serve as additional tests,

over and above numbers 1 and 2 above, for determining when a use is

attainable. Clearly these use removal criteria (131.10(g)) are designed

to determine whether a use is attainable and therefore can serve that

purpose equally effectively when considering whether to remove a

designated use (the situation where they are clearly required to be

used) and when considering whether a use is attainable and should be

designated. The discussion below on use attainability analysis (UAA)

and non section 101(a)(2) uses further discusses the relationship

between designation of attainable uses, UAAs, and the analysis required

to justify use removal. That discussion solicits comment on whether the

use removal criteria at Sec. 131.10(g), in addition to being the

regulatory justifications for use removal, should, consistent with

EPA\'s interpretation of the regulation, be included in the basic

elements of a UAA.

Despite what EPA believes are fairly clear guidelines in the

current regulation and guidance, questions have been raised about EPA\'s

minimum attainability requirements. The Agency\'s current thinking is

that basic attainability requirements, the methods for demonstrating

attainability, the circumstances under which attainability analysis

must be done, and what that analysis must consist of should be

clarified in the regulation.

b\. Removal of Designated Uses. The regulation (at 40 CFR 131.10(g))

specifies that States and Tribes may remove a designated use which is

not an existing use if attainment of a use is not feasible due to the

following:

\(1\) Naturally occurring pollutant concentrations prevent the

attainment of a use; or,

\(2\) Natural, ephemeral, intermittent, or low flow conditions or

water levels prevent the attainment of the use, unless these conditions

may be compensated for by the discharge of sufficient volume of

effluent discharges without violating State or Tribal water

conservation requirements to enable uses to be met; or,

\(3\) Human caused conditions or sources of pollution prevent the

attainment of the use and cannot be remedied or would cause more

environmental damage to correct than to leave in place; or;

\(4\) Dams, diversions or other types of hydrological modifications

preclude the attainment of the use, and it is not feasible to restore

the water body to its original condition or operate such modification

in a way that would result in the attainment of a use; or,

\(5\) Physical conditions related to the natural features of the

water body, such as the lack of a proper substrate, cover, flow, depth,

pools, riffles, and the like, unrelated to water quality, preclude

attainment of aquatic life protection uses; or,

\(6\) Controls more stringent than those required by Sections 301(b)

and 306 of the Act would result in substantial and widespread economic

and social impact.

The use removal criteria were included in the regulation to address

those circumstances where the attainability of certain uses would be

precluded by conditions over which the water quality protection

provisions in the regulation had little or no control. The

uncontrollable conditions considered most likely to limit attainability

were: natural water quality or habitat limitations, irretrievable

human-caused contamination or conditions, or insupportable economic and

social costs. These general

\[\[Page 36755\]\]

conditions, then, formed the basis for the six use removal criteria.

Although EPA believes the use removal criteria have functioned

reasonably well, the growing number and reoccurring nature of the

questions raised about these criteria have convinced EPA of the need to

review this central element of the program.

Some have argued that the six criteria and their interpretation are

overly stringent, making any proposal to remove a designated use futile

even where a use was \`\`mistakenly\'\' designated. Others argue that
the

use removal criteria and their interpretation are overly generous,

granting the possibility of use removal where the principal stressor is

a condition which should not be immune from the water quality

protection provisions in the federal regulation (operation of dams is

one example used in arguing this position). Others complain that there

seems to be no national consistency in the way the use removal criteria

are interpreted by EPA, the States or the Tribes. And, finally,

questions also have been raised about whether or not the criteria

adequately address or apply to all uses equally. The key to appropriate

application of the use removal criteria is to focus on whether or not a

condition, at a specific site, would preclude attaining a designated

use. A decision on this question is not always straightforward however,

and as a result, there are questions about the application of the use

removal criteria. A few examples may help the discussion.

Criterion number 1 allows removal of a designated use where

\`\`naturally occurring pollutant concentrations prevent attainment of

the use.\'\' A reoccurring question about this provision is: under what

circumstances should \`\`naturally occurring pollutant
concentrations\'\'

be the justification for use removal versus the basis for calculating

site-specific criteria, acknowledging that the natural condition

defines the existing use? Often, the numerical criteria assigned to the

designated use are the initial benchmark for estimating whether or not

a designated use will be attained. In this approach, a comparison of

the natural condition with the numerical criteria is used in the

evaluation of attainability. Where such an analysis demonstrates

clearly that the naturally occurring pollutant concentrations would

preclude the designated use, the use may be removed. There are,

however, examples of situations where statewide or national criteria

for one or more contaminants are exceeded, and yet the available

information on the overall condition of the water indicate the use is

supported. This situation is most common for aquatic life uses where

local populations of aquatic organisms may have acclimated to natural

conditions outside the estimated \`\`normal\'\' tolerance range, where

species on the edge of their distribution are reproducing but are

physiologically stressed or where broadly derived criteria may not be

appropriate for the particular aquatic community at that site. In such

a situation, the observed condition of the resource obviously will take

precedence over the predicted condition, and the natural water quality

will form the basis for site-specific criteria since the use is clearly

not precluded. Again, the key to answering the use removal question is

to determine whether or not \`\`natural conditions\'\' preclude
attainment

of the use, and because of the site-specific circumstances discussed

above, answering this question involves more than a simple comparison

of numeric criteria with the natural condition.

Criterion number 2 allows removal of a designated use where

natural, ephemeral, intermittent, or low flow conditions would preclude

the use unless these conditions may be compensated for by the discharge

of sufficient volume of effluent discharges without violating State or

Tribal water conservation requirements to enable uses to be met

(emphasis added). Questions have been raised about exactly what the

above italicized language means. EPA\'s interpretation of this phrase is

that, where an effluent discharge creates an essentially perennial flow

for what naturally would be ephemeral or intermittent waters, the

resulting aquatic community is to be protected. EPA\'s current thinking

is that in situations such as these, the second criterion for use

removal means that a State or Tribe cannot remove a use of a water body

where the augmented flow supports an aquatic life use.

Criterion number 4 allows removal of a use where dams, diversions

or other types of hydrological modifications preclude the attainment of

the use, and it is not feasible to restore the water body to its

original condition or operate such modification in a way that would

result in the attainment of a use. As indicated above, some have argued

that operation of dams is an inappropriate basis for concluding that

Section 101(a)(2) uses are not attainable, and they have suggested this

criterion be removed from the regulation. In arguing this position,

these commenters have pointed to the 1986 amendments to the Federal

Power Act (Electric Consumer\'s Protection Act, or ECPA) and the

legislative history of these amendments as an indication of Congress\'

intent to give equal priority to protecting and restoring fish and

wildlife habitat even where dams exist. Specifically, the ECPA states:

\* \* \*In deciding whether to issue any license the

\<SUP\>{\</SUP\>Federal Energy Regulatory Commission}, in addition to

the power and development purposes for which licenses are issued,

shall give equal consideration to the purposes of energy

conservation, the protection, mitigation of damages to, and

enhancement of fish and wildlife (including related spawning grounds

and habitat), the protection of recreational opportunities, and the

preservation of other aspects of environmental quality. (ECPA

amending the Federal Power Act, Section 4(e), 16 U.S.C. Section

797(e))

The legislative history, these commenters believe, provides a

particularly clear indication of congressional intent to protect and

restore aquatic life uses. They specifically point to that part of the

record which states that no one \`\`expect\[s\] \`business as usual,\'
\'\' but

rather the expectation is that:

\[P\]rojects licensed years earlier must undergo the scrutiny of

today\'s values as provided in this law and other environmental laws

applicable to such projects. If nonpower values cannot be adequately

protected, FERC should exercise its authority to restrict or,

particularly in the case of original licenses, even deny a license

on a waterway. (H.R. Rep. No. 99-934, 99th Cong., 2d Sess. (1986) at

22\)

Groups arguing for removal of criterion 4 use the amendments to the

Federal Power Act as an example of the recognition being given today\'s

environmental values and the importance of restoring and enhancing the

aquatic habitats and recreational uses of water resources. They

maintain that \`\`\...the Water Quality Rule should be updated to

recognize that aquatic and recreational uses can not be removed based

simply on the existence of a dam.\'\' EPA\'s current thinking is that
the

above rationale and legislative history raise a serious question about

whether the existence of a dam and the infeasibility of operating that

dam in a way that will result in attaining the designated use, measured

against today\'s values, is sufficient reason to remove a designated

use. EPA is interested in commenters views on this issue.

Criterion number 5 allows removal of a designated use where

physical conditions related to the natural features of the water body,

such as the lack of proper substrate, cover, flow, depth, pools,

riffles, and the like, unrelated to water quality, preclude attainment

of

\[\[Page 36756\]\]

aquatic life protection uses. Notwithstanding the reference to aquatic

life uses in 131.10(g)(5), some have argued that recreational uses,

especially swimming uses, might also be limited by physical factors

(especially where safety is an issue), and they have asked whether or

not the physical factors consideration could be applied to evaluations

of recreational use attainability. As now written, the regulatory

language would not allow consideration of physical factors, alone, as

the basis for removing a designated recreational use. In the preamble

to the 1983 regulation, EPA explained that, while the Agency recognized

that physical factors also affect recreational uses, States, and now

Tribes, would need to give consideration to incidental uses of the

water body even though it may not make sense to encourage use of a

stream for swimming because of the flow, depth or velocity of the

water. Instead, the preamble discussion explained that based on prudent

public health considerations, the use protection question was not to be

judged wholly on an analysis of the water body\'s suitability for

swimming but rather on whether or not swimming would actually occur.

EPA\'s current thinking is that physical factors, alone, would not be

sufficient justification for removing or failing to designate a primary

contact recreation use.

EPA\'s suggested approach to the recreational use question has been

for States and Tribes to look at a suite of factors such as, the actual

use, existing water quality, water quality potential, access,

recreational facilities, location, safety considerations, and physical

conditions of the water body in making any use attainability decision.

The guidance suggests that any one of these factors, alone, may not be

sufficient to conclude that designation of the use is not warranted.

Nevertheless, there clearly are situations such as high flows caused by

storm events where the physical conditions of a water body would make

swimming, if not impossible, extremely dangerous. It is in addressing

situations such as these that questions have been raised about the

applicability of physical factors to the recreational use issue. The

question is sometimes posed in terms of whether or not a State or Tribe

would incur some liability by designating or continuing to designate

such waters as swimmable. They argue that a reasonable, common sense

approach is to acknowledge that there are certain waters for which

primary contact recreation is not an attainable use solely because of

the physical condition of the water. EPA is, therefore, considering

whether the regulation or Agency guidance should be amended to allow

consideration of physical factors, alone, as the basis for removing or

not designating primary contact recreational uses.

The above discussion is about EPA\'s interpretation of the

conditions that would have to be satisfied to either remove or not

designate recreational uses. As explained earlier in this section,

satisfying those conditions gives a State or Tribe the option of either

removing or not designating the use. It does not, however, create an

obligation. A specific example may help. A western State was concerned,

partly for liability reasons, about designating swimming uses for a

number of waters where the physical conditions and other factors made

swimming, if it did occur, unwise. Although available information

indicated the actual swimming use was limited or nonexistent, the State

also wanted to ensure protection of that use, based on public health

considerations, should it occur. The issue for the State was striking

the appropriate balance between the two concerns: the possibility of

inadvertently encouraging swimming where it should not occur because of

safety considerations and protecting that use if it did occur. To

resolve this issue, the State designated these waters for secondary

contact recreation but assigned primary contact recreation

bacteriological criteria to provide an appropriate level of protection

should swimming occur, however unlikely. In this way, the State felt it

did not inappropriately encourage swimming in these waters, but if

swimming did occur, the required water quality would provide an

appropriate level of protection. This is an approach to the

\`\`incidental use\'\' issue, discussed in the existing use section of
this

chapter, that, while acknowledging uncertainty, errs on the side of

protectiveness.

Consistency

EPA has provided guidance on implementing the requirements in

Sec. 131.10(g). Although EPA believes the guidance has been fairly

comprehensive and has functioned reasonably well, the growing number

and recurring nature of the questions raised about implementation of

the use removal criteria have convinced EPA to solicit comments on the

need for additional guidance or regulatory changes to ensure

appropriate and consistent application of the use removal criteria.

As indicated in the introduction to this discussion, one of the

reoccurring concerns about implementation of Secs. 131.10(j) and

131.10(g) with respect to designating or removing uses, is that to

some, there are instances of inconsistency in the way the

Sec. 131.10(g)(1)-(6) criteria are interpreted by EPA, the States or

the Tribes. One example that has been cited is that the application of

the fish consumption use is dissimilar in different regions of the

country. In one area of the country, some maintain, the fish

consumption use is applied to all waters assigned any aquatic life use

without regard to whether or not there is a credible exposure pathway

to humans by way of contaminated fish. In other areas of the country,

the application of the fish consumption use allows consideration of

occurrence, size and species of fish present and evidence that fishing

actually occurs as a basis for concluding that there is a potential

exposure pathway and the use should be designated. An associated

consistency issue has to do with the manner in which the terms in

Sec. 131.10(g) are interpreted. An example is the term \`\`feasible\'\'
in

criterion number 4. Feasibility could be based on technical

considerations, such as the ability to operate an impoundment in an

efficient manner that does not degrade water quality, as EPA intended

when it originally wrote the regulation. Alternatively, some have

suggested that feasibility could be based on economic considerations or

a balanced consideration of cost and technology (EPA\'s current thinking

is that the term \`\`feasible\'\' in use removal criterion number 4,

regarding the operation of dams should continue to refer to technical

feasibility and not to economic feasibility. Criterion number 6, not

number 4, is the appropriate avenue to address economic feasibility of

attaining the designated use because it establishes an appropriate test

of economic infeasibleness.)

EPA\'s view is that the use removal criteria should be clear and

consistently interpreted. Questions and/or positions such as those

described above suggest there may be a need for additional guidance on

or interpretation of Sec. 131.10(g) to ensure the Sec. 131.10(g)

criteria are consistently interpreted and applied, and to address

whether review under Sec. 131.10(g) could be done for categories of

sources.

c\. Use Attainability Analysis. A use attainability analysis (UAA)

is a structured scientific assessment of the factors affecting the

attainment of uses specified in section 101(a)(2) of the Act (the

\`\`fishable/swimmable\'\' uses). The factors to be considered in such
an

analysis include the physical, chemical, biological, and economic use

removal

\[\[Page 36757\]\]

criteria described in the current regulation (40 CFR 131.10(g)(1)-(6)).

The current regulation (40 CFR 131.10(j)) establishes the requirement

that States and Tribes conduct a UAA when designating uses that do not

include the section 101(a)(2) uses, removing section 101(a)(2) uses, or

designating new subcategories of section 101(a)(2) uses that require

less stringent criteria.

New Information for Waters Without Section 101(a)(2) Use Designations

The current regulation (Sec. 131.20(a)) specifically requires the

re-examination of water bodies with less than Section 101(a)(2) use

designations every three years to determine if new information has

become available. If new information indicates that a use is

attainable, the State or Tribe is to revise the use accordingly. EPA

interprets the current regulation as requiring review of past UAA-based

use designation decisions when there is new information that could have

a bearing on that use designation decision.

The 1983 preamble to the regulation explained that a State or Tribe

need only conduct a UAA once for a given water body. The preamble went

on to explain, however, that where the UAA is used as justification for

removing a section 101(a)(2) use or failing to designate a section

101(a)(2) use, the State is required to review the basis for that

decision in subsequent triennial reviews to determine whether or not

the circumstances have changed in a way that would alter the original

decision. EPA recognizes that the requirement to review new information

about past UAA-based use designation decisions, because it creates a

demand for further analysis of the decision by the State or Tribe, can

serve to discourage States and Tribes from generating new information.

EPA\'s current thinking is that interested parties should be encouraged

to generate and consider relevant information that could have a bearing

on the use designation decision for a particular water and that the

trigger for reviewing past use designation decisions should be clear.

In addition, EPA is interested in comments on whether there should be

some definable burden placed on the State or Tribe to actively seek

information for such waters. The Agency may need to be more specific in

requiring that States and Tribes specify the procedures they will use

in identifying water bodies where \`\`new information\'\' has become

available and ensuring new information is generated where appropriate.

UAAs and Non Section 101(a)(2) Uses

The current regulation indicates that the UAA requirements apply to

uses specified in Section 101(a)(2) of the Act. The regulation at 40

CFR 131.10(j) specifically requires that a State or Tribe conduct a UAA

where: \`\`(1) the State \[or Tribe\] designates or has designated uses

that do not include the uses specified in Section 101(a)(2) of the Act,

or (2) the State \[or Tribe\] wishes to remove a designated use that is

specified in Section 101(a)(2) of the Act or to adopt subcategories of

uses specified in Section 101(a)(2) of the Act which require less

stringent criteria.\'\' Although the regulation at 40 CFR 131.10(g) has

always provided that States and Tribes may not remove a designated use

unless they can demonstrate that attaining the use is not feasible, the

regulatory language does not expressly require the State or Tribe to

conduct a UAA as defined in 40 CFR 131.10(j) before a use not

referenced in section 101(a)(2) may be removed. As a result, some have

questioned whether or not the UAA requirements actually apply to uses

other than those referenced in Section 101(a)(2), such as water supply

or agriculture. EPA\'s position on this issue is that, while the

analysis to downgrade a use not included in CWA section 101(a)(2) is

not expressly referenced in Sec. 131.10(j), 40 CFR 131.10(g) of its own

terms requires the State or Tribe to document whether any use being

considered for removal is attainable under the six criteria outlined in

that section. Where such a use is shown to be attainable, it may not be

removed (downgraded). In practice, EPA believes there is no cognizable

difference between these two analyses. EPA is thus considering whether

it should combine these elements of 40 CFR 131.10(g) and 131.10(j) or

otherwise clarify the relationship between these provisions in the

regulation. Given EPA\'s position that the regulation requires the use

attainability of a water body to be documented before any of its uses

may be removed, EPA is interested in a discussion of specific

attainability issues that might arise in applying the UAA requirements

to non-Section 101(a)(2) uses such as water supply or agriculture.

Information in UAAs

The regulation is not specific about what a UAA should contain

other than the general description contained in the definition of a UAA

at 40 CFR 131.3(g). Instead, EPA has issued various national and

regional guidance documents to assist with the completion of such

analyses. Some have suggested, however, that the regulation be amended

to provide more specificity on information needed in a UAA. Topics for

consideration might include: what specific questions should a use

attainability analysis address? what are the data requirements? and

what are the requirements for reporting the results of the analysis?

EPA seeks comment on this issue.

UAAs and Refinement of \`\`Fishable/Swimmable\'\' Use Designation

As long as a State or Tribe designates uses that fall within the

broad range of uses consistent with the section 101(a)(2) goals, there

is no requirement to conduct a UAA. In fact, 40 CFR 131.10(k)

explicitly states that \`\`a State is not required to conduct a use

attainability analysis . . . whenever designating uses which include

those specified in section 101(a)(2) of the Act.\'\' As a result, there

does not appear to be a mechanism that ensures State or Tribal waters

are not under-classified (i.e., a use subcategory is designated for a

water when a higher or more protective subcategory is actually

attainable). Some have suggested that the regulation be amended or

guidance clarified to require a UAA (i.e., a structured scientific

assessment) whenever an aquatic life use is designated (or refined) to

ensure the level of protection assigned matches the potential for the

water body. EPA\'s current thinking is that there needs to be a solid

underlying rationale for use designations. One of the emerging themes

from EPA and the larger community of parties interested in further

protecting water quality is that refining designated uses and tailoring

suites of criteria to the refined uses in watersheds is an important

future direction of this program. Clearly for this approach to succeed,

a solid evaluation of attainability must be at the heart of any

decision to characterize designated uses in greater detail than has

been the norm. EPA is interested in comment on this view, in particular

as it relates to the rebuttable presumption that the generic uses

described as fishable/swimmable are attainable.

Thresholds for Aquatic Life Use Designation

In part 2 of this section, \`\`Refined Designated Uses\'\', there is a

discussion explaining EPA\'s position that the definition of \`\`aquatic

life\'\' is not limited to those waters that support \`\`fisheries.\'\'
That

discussion explains that a more biologically-grounded definition of

aquatic life would be sufficiently expansive to include aquatic

communities made up, for example,

\[\[Page 36758\]\]

entirely of invertebrate organisms. This broad definition of \`\`aquatic

life uses\'\' has an impact on the manner in which UAAs are planned and

evaluated. The current regulation allows States and Tribes to designate

uses for certain waters that do not include the section 101(a)(2) uses,

where such uses are not attainable. As a result, some States and Tribes

have waters which have not been assigned an aquatic life designated

use. However, if aquatic life uses are defined broadly, as EPA believes

they should be, there would be very few, if any, waters that would not

be considered as supporting some type of existing aquatic life use.

Aquatic communities form a continuum, making it difficult, if not

impossible in the biological sense, to identify where the threshold for

aquatic life use begins. As a result, some have suggested that a broad

definition of aquatic life would appear to revoke the option of

excluding aquatic life protection from a water body since essentially

all waters support some level of aquatic life. They have suggested,

therefore, that there is a need to identify a threshold, based on some

physical rather than biological limitation, that could be used as an

acceptable justification for concluding that an aquatic life use is not

attainable. For example, some States and Tribes have urged the use of a

flow-based threshold to justify a conclusion that an aquatic life use

in not attainable. Generally, ephemeral waters (waters whose channel

does not intersect the ground water table and which are dependent on

precipitation events for their flow) are suggested as an appropriate

threshold. In a biological sense, this may not be a satisfactory

solution since there are ecologically important ephemeral waters which

should receive aquatic life use protection regardless of the temporal

nature of the flow. This is especially true for many ephemeral

wetlands. EPA is considering whether changes are needed in the

regulation or guidance to address whether, and under what

circumstances, UAAs may be used to justify a non-aquatic life use

classification, given the broad range of aquatic communities that may

exist.

Request for Comments on Use Removal and Use Attainability

EPA seeks comment on the following questions:

1\. Although EPA believes the use removal criteria in Sec. 131.10(g)

have functioned reasonably well, questions have been raised about the

applicability of specific section 131.10(g) criteria and the manner in

which EPA interprets those criteria. EPA seeks comment on the use

removal criteria. Are the six criteria sufficiently comprehensive or

should other factors be considered as a basis for removing designated

uses? Are the criteria too comprehensive and are certain of the

criteria inappropriate as a basis for designated use removal? Is there

a need to modify the existing criteria to more clearly address the full

range of use removal issues that have developed since the regulation

was originally published?

2\. Even with the statements in the current regulation, questions

have been raised about the minimum requirements of a use attainability

analysis. Is there need for further clarification in guidance, policy

or in the regulatory text on this issue?

3\. Triennial review of UAA-based use designations that do not

include section 101(a)(2) uses, are currently triggered only when new

information becomes available. Should EPA require that States and

Tribes specify procedures they will use in identifying what constitutes

new information and thus when the review of the UAA-based use

designations is required?

4\. Although 40 CFR 131.10(g) requires an assessment of

attainability before removal of any designated use, the regulatory

language does not expressly require an analysis called a UAA as

specified in 40 CFR 131.10(j) any time a State or Tribe seeks to

designate a non section 101(a)(2) use. EPA, however, believes that the

analysis under either provision is equivalent. Should the current

regulation be revised to clarify that the UAA requirements apply to any

\`\`downgrade\'\' of a use and not just the CWA Section 101(a)(2) uses?
Can

any needed clarification be achieved through guidance or policy? EPA

would be interested in comments on factors to be considered in

evaluating the attainability of non Section 101(a)(2) uses, such as

water supply or agricultural uses which generally take place after the

water is diverted from the natural water body.

5\. How should the water quality standards regulation, guidance or

policy be modified to provide more specificity on appropriate factors

to consider in developing a use attainability analysis?

6\. In order to ensure the present aquatic life use designation (or

use subcategory) matches the attainable level of aquatic life use in a

water body, should the water quality standards regulation, policy or

guidance be modified to clarify that a periodic review of designated

uses is required where a State or Tribe has designated only marginal or

limited aquatic life uses?

7\. Are changes needed in the water quality standards regulation,

policy or EPA guidance to address whether, and under what

circumstances, use attainability analyses may be used to justify a non-

aquatic life use classification, given the broad range of aquatic

communities that may exist?

d\. Alternatives to \`\`Downgrade\'\' of the Designated Use. As

discussed above, where a State or Tribe believes that a particular

designated use is not attainable, States and Tribes have the option of

refining a water body\'s designated use, for example by creating

subcategories of the use and describing the use in more detail. A

subcategory can, and may need to be, water body-specific if the State\'s

or Tribe\'s use classification system is not sufficiently precise to

accommodate the subcategory of designated use for the water body in

question. States and Tribes also have the option of removing the

designated use and replacing the removed use with a new one that, under

the regulation, reflects attainable conditions in the water body. Use

removal and to a lesser extent refinement are also commonly referred to

as use \`\`downgrade.\'\' Both of these options, refinement and removal
of

the designated use, are not time-limited. That is, the designated use

that results from exercising either of these options becomes the new

goal use of the water body. In the following discussion, three

alternatives to use downgrade that have been used by States are

presented. They are variances, temporary standards, and ambient-based

criteria. These alternatives are less \`\`draconian\'\' than use

downgrading in the sense that they can provide adjustments to

particular aspects of the standards\--i.e., to the criteria for

particular pollutants or the criteria as applied to certain

dischargers\--without changing the designated use and the full suite of

criteria to protect the designated use. EPA\'s current thinking is that

often the attainable condition of particular water bodies is not well

understood due to uncertainty about expected results of water quality

improvement actions. In such situations, EPA believes it may be

appropriate to implement water quality protection actions, assess the

results of those actions, and implement additional measures where

necessary to continue to improve water quality. EPA believes that

iterative assessment and implementation in these types of situations is

probably the best way to gain an understanding of the ultimate

attainable condition of the water body. The mechanisms described below

may be well-suited to this situation because they leave the designated

use of the

\[\[Page 36759\]\]

water body, the ultimate goal, in place while providing a defined

period of time (in the case of variances and temporary standards) to

document, through implementation and assessment, the water quality

improvements that are possible through various measures and thus, the

attainability of the goal.

i\. Variances. One option authorized under the regulation that is

used by some States or Tribes is the water quality standard variance. A

variance is a short-term exemption from meeting certain otherwise

applicable water quality standards. EPA authorizes States and Tribes to

include variances in their water quality standards. (see 40 CFR

131.13). Agency guidance on variances identifies what the Agency

believes to be the essential elements of a variance:

\--a variance should be granted only where there is a demonstration that

one of the use removal factors (40 CFR 131.10(g)) has been satisfied;

\--a variance is granted to an individual discharger for a specific

pollutant(s) and does not otherwise modify the standards;

\--a variance identifies and justifies the numerical criteria that will

apply during the existence of the variance;

\--a variance is established as close to the underlying numerical

criteria as is possible;

\--a variance is reviewed every three years, at a minimum, and extended

only where the conditions for granting the variance still apply;

\--upon expiration, of the variance, the underlying numerical criteria

have full regulatory effect;

\--a variance does not exempt the discharger from compliance with

applicable technology or other water quality-based limits; and

\--a variance does not affect effluent limitations for other

dischargers.

With these safeguards in place, the principal difference between a

variance and a downgrade of a designated use is that a variance is

temporary. That is, when the variance expires, an affirmative showing

would be needed to continue it, or the underlying standards are

applicable. Because a variance is temporary, it actively supports the

improved water quality goal, and it can, under appropriate

circumstances serve as an environmentally preferable alternative to

what otherwise might become a permanent change in a designated use.

Historically, the intent of the variance provision has been to:

provide a mechanism by which permits can be written to meet a modified

standard where discharger compliance with the underlying water quality

standard is demonstrated to be infeasible within the meaning of

Sec. 131.10(g) at the present time (e.g., meeting the standard would

cause substantial and widespread social and economic impact); encourage

maintenance of original standards as goals rather than removing uses

that may be ultimately attainable; and ensure the highest level of

water quality achievable during the term of the variance.

EPA has approved State and Tribal use of variances when the

individual variance is included in State or Tribal water quality

standards, each variance is subject to the same public review as other

changes in water quality standards, the State or Tribe demonstrates

that meeting the standard is unattainable based on one or more of the

grounds listed in 40 CFR 131.10(g) for removing a designated use,

existing uses are protected, the variance secures the highest level of

water quality attainable short of achieving the standard and the State

or Tribe demonstrates that advanced treatment and alternative effluent

control strategies have been considered (See 48 FR 51400, 51403 (Nov.

8, 1983); Water Quality Standards (WQS) Handbook at 5-12; Memorandum

from EPA\'s Office of Water, \`\`Variances in Water Quality
Standards,\'\'

March 15, 1985; and Decision of the General Counsel No. 58, In Re

Bethlehem Steel Corporation, March 29, 1977).

The Preamble to the 1983 water quality standards regulation

revision suggested that substantial and widespread social and economic

impact, the sixth element for use removal under Sec. 131.10(g), is an

important and appropriate test that, if met, could be used as the basis

for granting a variance (see 48 FR 51403). Subsequently, on March 15,

1985, EPA issued further guidance on the conditions under which a

variance might be granted. The 1985 EPA Office of Water guidance

explained that it would be appropriate to grant short-term variances to

individual dischargers based on any of the six factors for removing a

designated use as listed at Sec. 131.10(g). As variances represent a

temporary downgrade in the water quality standards, EPA reasoned that

more stringent treatment of variances than permanent downgrades would

not be appropriate. In practice, however, the only factor that is

commonly used to grant a discharger-specific variance is the economic

test. The Office of Water guidance continued to interpret variances as

being limited to individual dischargers.

In \`\`Guidance for State Implementation of Water Quality Standards

for CWA Section 303(c)(2)(B)\'\' (December 1988; Notice of Availability

published at 54 FR 346, January 5, 1989), EPA recommends that States

and Tribes adopt a variance provision whenever adopting statewide or

tribe-wide criteria for a large number of toxic pollutants for human

health or aquatic life protection. The rationale behind this

recommendation was to avoid unreasonable consequences from adopting

State- or Reservation-wide criteria which could underestimate or

overestimate the toxic potential of some pollutants in a specific water

body.

The Water Quality Guidance for the Great Lakes System (Great Lakes

Guidance) published March 1995 by EPA (56 FR 15366, March 23, 1995; 40

CFR section 132) contains provisions allowing for variances from water

quality standards. Variances granted under the Great Lakes Guidance are

pollutant-specific and point source-specific and are limited to five

years or the term of the NPDES permit implementing the variance,

whichever is less. Variances may be granted for any of the reasons

listed at 40 CFR 131.10(g) for which a use downgrade may be considered.

Like all revisions to State or Tribal water quality standards, EPA

review and approval is required of any variance granted by a State or

Tribe and variances may be renewed following the same procedure

originally used for applying for a variance. Variances are also subject

to review as part of a State\'s or Tribes triennial review of water

quality standards. Multiple discharger variances (a variance that

applies to multiple point sources discharging to the same water body)

are also allowed under the Great Lakes Guidance. Variances granted

under the Great Lakes Guidance provisions may not jeopardize the

continued existence of any Federally listed threatened or endangered

species. Further, under the Guidance, variances are not available for

new or recommencing discharges. A recommencing discharge is a source

that recommences discharge after terminating operations. (40 CFR

122.2).

The Great Lakes Guidance was developed in concert with many other

provisions addressing designated uses, criteria, antidegradation and

various implementation policies for the Great Lakes States and Tribes.

Any evaluation of the level of protection afforded water quality under

the Great Lakes Guidance variance procedures should be made in the

context of the Great Lakes Guidance as a whole. Similarly, the water

quality standards regulation is more than simply the sum of its parts.

Any

\[\[Page 36760\]\]

approach to the implementation of water quality standards variances

must be evaluated in the context of the entire regulation.

EPA is considering whether implementation of the variance provision

has been a useful component of the water quality standards program, and

the overall program for protection of water quality standards. In 1990,

EPA conducted a survey of State variances and variance provisions

(National Assessment of State Variance Procedures, Report, November

1990, Office of Water Regulations and Standards). This study showed

that variances had been granted on a very limited basis. In fact, only

16 out of 57 States and Territories had granted variances and some of

those had done so infrequently. EPA lacks detailed information on why

variances are not being significantly utilized in most States and

Tribes. EPA is interested in information regarding alternative

mechanisms that are being used by States or Tribes in lieu of variances

to provide necessary short term and temporary relief from applicable

criteria, and how any alternative approaches address the feasibility of

ultimately attaining the criteria associated with the underlying

designated use.

EPA is considering whether it would be useful to include in the

regulation more explicit language reflecting current EPA thinking and

practice regarding variances. As explained above, in order to issue

variances, States or Tribes must include variances as part of the

State\'s or Tribe\'s water quality standards. EPA believes, however,
that

in some instances States may be misusing variances. For example, over

the years, there have been instances where a State has improperly

granted a \`\`variance\'\' from compliance with NPDES permit limits,

failing to include these variances within the water quality standards

themselves. There has also been some confusion regarding the necessity

of formal adoption of individual variances into State and Tribal water

quality standards and whether the public participation process

associated with NPDES permit issuance sufficiently addresses those same

needs for variance adoption. EPA is also considering whether to specify

the degree to which individual dischargers must document the continued

need for a variance before the variance can be renewed at each

triennial review. EPA is considering whether the water quality

standards regulation should provide more specific guidelines on the use

and content of variance policies. EPA\'s current thinking is that the

regulation may need to articulate certain aspects of variances more

explicitly, including:

\--explicit reference to the criteria listed in 40 CFR 131.10(g) as the

criteria for granting a variance;

\--explicit statement that the granting of a variance may not result in

any loss or impairment of an existing use;

\--explicit statement that before a variance can be granted, the

applicant must provide documentation that treatment more advanced than

that required by sections 303(c)(2)(A) and (B) of the CWA has been

carefully considered, and that alternative effluent control strategies

have been evaluated and reasonable progress is being made toward

meeting the underlying or original standards;

\--explicit statement requiring the highest level of water quality

achievable under the relaxed, interim standard during the period of the

variance.

\--explicit statment that a variance shall not be granted if standards

will be attained by implementing cost-effective and reasonable best

management practices for nonpoint source control.

EPA believes that such a clarification of its policy regarding

variances could serve to encourage proper use of variances by States

and Tribes while at the same time reducing the possibility of

inappropriate use.

ii\. Temporary Standards. As indicated in the discussion on

variances above, the 1985 EPA Office of Water guidance explained that

it would be appropriate to grant short-term variances to individual

dischargers based on any of the six factors for removing a designated

use as listed at Sec. 131.10(g). Of the six use removal factors, the

first five address water quality and habitat features of the water body

as a whole. These same factors are not, however, ideally suited to

making decisions about the capabilities of individual dischargers. For

example, it is not immediately clear how use removal factor five,

\`\`physical conditions related to natural features of a water body \*
\* \*

preclude attainment of a use\'\', could be applied to a decision about
an

individual discharger. On the other hand, the sixth factor, the

substantial and widespread economic and social impact factor, is well

suited to decisions about individual dischargers which explains why the

economic hardship test has been historically applied in evaluating

variances.

Several States have applied factors similar to the first five use

removal factors in establishing variances for entire water body

segments or portions of water body segments. These States sometimes

refer to these as \`\`temporary standards\'\' or \`\`temporary

modifications\'\'. This has been done where the problems in a water body

are significant and widespread, involving point and nonpoint sources of

pollution and their impacts on water quality and habitat, that is

waters significantly impaired by multiple sources and not just one or a

few point sources. For example, where historic mining practices have

severely impaired both water quality and habitat throughout a headwater

basin, temporary standards have been used. Rather than downgrading

these waters, the States have applied temporary standards with specific

expiration dates for certain pollutants affected by the historic mining

practices. In this way, the States have maintained designated uses and

underlying criteria for other pollutants, while recognizing that

existing ambient conditions for certain pollutants are not correctable

in the short-term. In such cases, the temporary standards provide a

basis for permit limits in the shorter-term. The temporary standards

approach is then used by these States as the basis for remediation of

damaged water resources because the underlying designated use and

criteria to protect that use actively drive water quality improvements

in the longer-term. EPA Regional Offices have approved the use of such

temporary standards.

Temporary standards have been implemented to date with little

specific Agency guidance on a water body approach to variances. EPA is

considering whether the water quality standards regulation or guidance

should specifically address temporary standards. EPA\'s current thinking

is that if the regulation or Agency guidance were to specifically

address temporary standards, such regulation or guidance would need to

address certain relevant issues including: application criteria to be

used in deciding which waters might qualify for temporary standards; a

way of identifying the existing, impaired water quality conditions; a

mechanism for specifying the water quality needed to fully attain the

anticipated uses; and a plan and driving mechanism aimed at achieving

needed water quality and habitat improvements to fully support

compliance with the designated uses.

Where EPA has provided guidance to individual States on use of

State temporary standards provisions, EPA has advised that any

temporary standard should:

\--be granted only where there is a demonstration that one of the use

removal factors (40 CFR 131.10(g)(1) through (6) has been satisfied;

\[\[Page 36761\]\]

\--be granted for a specific water body or portion of a specific water

body as defined in State standards;

\--identify and justify the numerical criteria that will apply during

the existence of the temporary standard and identify a \`\`remediation

plan\'\' aimed at compliance with the underlying designated uses and

criteria;

\--be established as close to the underlying numerical criteria as is

possible;

\--be reviewed every three years, at a minimum, and extended only where

the conditions for granting the temporary standard still apply;

\--be in effect only for the specified term of the temporary standard

(or extension thereof), and upon expiration of the temporary standard,

the underlying numerical criteria have full regulatory effect;

\--not exempt any discharge to the water body from compliance with

applicable technology or water quality-based limits (based on the

temporary standards) or best management practices;

\--not apply to any new discharger to the water body; and

\--protect existing uses.

EPA is considering whether the use of temporary standards

represents a viable alternative to use refinement or removal. EPA is

also considering whether the regulation or guidance should explicitly

address use of temporary standards, including specific limitations on

the use of temporary standards like those listed above.

iii\. Ambient-based Criteria. On a limited basis, States have

developed and EPA has approved \`\`ambient-based criteria.\'\' These

ambient-based criteria have been developed for specific water bodies

and pollutants where such criteria are shown to protect the designated

use and the existing use. EPA believes that ambient-based criteria can

be preferable to a \`\`downgrade\'\' of a use because the underlying

designated use is retained and because they may be limited to only a

small subset of pollutants.

EPA has issued a policy memorandum concerning one type of ambient-

based criteria, site-specific criteria for aquatic life protection that

are based on natural conditions. (See Memorandum from Tudor T. Davies,

Director Office of Science and Technology, Subject: Establishing Site-

Specific Aquatic Life Criteria Equal to Natural Background, November 5,

1997.) This policy states that States and Tribes may establish site-

specific aquatic life criteria equal to natural background conditions,

but such criteria must be scientifically defensible. Additionally, the

State\'s or Tribe\'s water quality standards should contain or provide

specific authority for site-specific criteria based on natural

background. States and Tribes should also identify procedures for

determining natural background. EPA\'s current policy also states that

the State or Tribal procedure for determining natural background needs

to be specific enough to establish natural background concentration

accurately and reproducibly. States and Tribes should also provide for

public notice and comment on the provision, the procedure and the site-

specific application of the procedure. The States or Tribes will also

need to document the resulting site-specific criteria in its water

quality standards, including specifying the water body segment the

site-specific criterion applies to. This can be accomplished through

adopting the site-specific criteria into the State and Tribal water

quality standards, or, alternatively by appending the site-specific

criteria to the water quality standards.

In addition, a second approach that some States have used and EPA

has approved is where the State or Tribe could have met the test for

downgrading a use under 40 CFR 131.10(g)(3) i.e., \`\`Human caused

conditions or sources of pollution prevent the attainment of the use

and cannot be remedied or would cause more environmental damage to

correct than to leave in place\'\', but instead of downgrading the use,

the State or Tribe established certain criteria based on ambient

conditions where those ambient conditions were shown to be

irreversible. In addition to assuring that the existing use is

protected, EPA is interested in assuring that where the ambient

concentration of a pollutant cannot be improved, i.e., it is

irreversible, that such condition be maintained and not made worse.

When this occurs, EPA believes that for other pollutants in the same

water body for which applicable criteria are being or can be met, those

criteria should remain in place and not be made less protective via a

use downgrade. EPA\'s current thinking is that the ambient-based

criteria need to be the best attainable. In addition, EPA\'s current

thinking is that in order to establish ambient-based criteria, the

State or Tribe should conduct an analysis equivalent to a use

attainability analysis for a downgrade that should include a thorough

description of the biota that will be protected via applicable water

quality criteria (both the unchanged pre-existing criteria and the

ambient-based criteria).

EPA is interested in hearing comments regarding these ambient-based

criteria mechanisms, and specifically whether the regulation should

discuss these mechanisms more specifically, and whether the regulation

should be more explicit about the biological evaluation necessary to

describe the aquatic life use being protected. EPA is also interested

in comments on whether the other relief mechanisms based on the

Sec. 131.10(g) reasons, such as variances and temporary standards,

should also require criteria which reflect the best attainable

conditions.

Request for Comments on Alternatives to Downgrading a Designated Use

EPA seeks comment on the following questions:

1\. EPA requests comment on whether variances, temporary standards

and/or ambient-based criteria can under certain circumstances offer an

environmentally preferable alternative to refinement or removal

(downgrade) of the designated use? Under what circumstances?

2\. Does the current water quality standards regulation or Agency

guidance or policy discourage persons from seeking variances and/or

discourage States and Tribes from granting variances (including

temporary standards)? What components of the procedures are most

problematic?

3\. Reflecting EPA\'s current interpretation of the regulation,

should the regulation make explicit that individual variances and

temporary standards must be documented in a State\'s or Tribe\'s water

quality standards before implementation as part of NPDES permits?

4\. Reflecting EPA\'s current interpretation of the CWA and the

regulation, should the regulation contain express reference to the

factors listed in 40 CFR 131.10(g) as the criteria under which a

variance (including temporary standards) from water quality standards

will be allowed? Should any of these factors be deleted? Should any new

factors be added?

5\. Reflecting EPA\'s current interpretation of the CWA and the

regulation regarding existing uses, should the variance portion of the

regulation at 40 CFR 131.13 underscore that the granting of a variance

must not result in any loss or impairment of an existing use, for

example by cross-referencing the requirement at 40 CFR 131.12(a)(1)

that existing uses must be protected?

6\. To reflect current practice and EPA guidance, should the

regulation be

\[\[Page 36762\]\]

amended to require documentation by either the applicant or the State

or Tribe demonstrating that treatment more advanced than that required

by sections 303(c)(2)(A) and (B) of the CWA has been carefully

considered, and that alternative effluent control strategies have been

evaluated and reasonable progress is being made toward meeting the

underlying or original standards?

7\. Should the regulation require that States and Tribes document in

their water quality standards the criteria that are applicable to the

water body or segment thereof during the period of a variance or

temporary standards?

8\. Should the regulation discuss ambient-based criteria mechanisms

more specifically?

9\. Should the regulation be more explicit about the biological

evaluation necessary to describe the aquatic life use being protected

where ambient-based criteria are used?

10\. EPA is also interested in comments on whether the other relief

mechanisms based on the Sec. 131.10(g) reasons, such as variances and

temporary standards, should in the regulation, expressly be required to

require criteria which reflect the best attainable conditions?

11\. Do the alternatives to use removal help address pulsed or

intermittent impacts, such as those from urban and rural runoff?

C. Criteria

The following section discusses water quality criteria in the water

quality standards programs. EPA is considering the implementation of

and effectiveness of different types of criteria and on the

desirability of changes to the water quality standards regulation as it

pertains to criteria. The scope of the criteria section includes all

Clean Water Act criteria for which EPA has issued national criteria

guidance, and several types of criteria for which there is no national

criteria guidance but where criteria guidance and policy are being

contemplated.

1\. Background

Water quality criteria are levels of individual pollutants or water

quality characteristics, or descriptions of conditions of a water body

that, if met, will generally protect the designated use of the water.

EPA, under section 304(a) of the Act, periodically publishes

recommendations (guidance) for use by States and Tribes to set water

quality criteria. Water quality criteria are developed to protect

aquatic life and human health, and in some cases wildlife, from the

deleterious effects of pollutants and other effects of pollution. There

are three principal categories of water quality criteria: criteria to

protect human health, criteria to protect aquatic life, and criteria to

protect wildlife. Within these broad categories, there are different

types of criteria, for example within the human health category, there

are chemical-specific and microbiological criteria. Within the aquatic

life category, there are chemical-specific criteria, toxicity criteria,

biological criteria, sediment criteria and physical criteria such as

habitat and flow balance. These criteria may be expressed in either

narrative or numeric forms. Many of these criteria may be developed to

apply generally, or they may be developed to apply to site-specific

situations. The CWA section 303(a)-(c) requires all States, and any

Tribe that has water quality program authority, to evaluate the need

for water quality criteria to protect a designated use and then adopt

water quality criteria (either EPA\'s or its own) sufficient to protect

uses designated for State or Tribal waters. Economic and technological

factors (e.g., the ability of analytical techniques to detect the

pollutant and treatment cost considerations) may not be used to justify

adoption of criteria that do not protect the designated use.

Narrative criteria are descriptions of conditions necessary for the

water body to attain its designated use. Often expressed as \`\`free

from\'\' certain characteristics, narrative criteria can be the basis
for

controlling nuisance conditions, e.g. floating debris or objectionable

deposits. Narrative criteria are often the basis for limiting toxicity

in discharges. States and Tribes establish narrative criteria where

numeric criteria cannot be established or to supplement numeric

criteria under 40 CFR 131.11(b)(2). When a water body is classified for

more than one use, criteria necessary to protect the most sensitive use

must be applied to the water body. 40 CFR 131.11(a).

CWA section 304(a) directs EPA to develop criteria guidance. These

criteria recommendations assist States and Tribes in developing water

quality standards. The AWQC are published pursuant to Section 304(a)(1)

of the CWA which states:

The Administrator \* \* \* shall develop and publish \* \* \* (and

from time to time thereafter revise) criteria for water quality

accurately reflecting the latest scientific knowledge (A) on the

kind and extent of all identifiable effects on health and welfare

including, but not limited to, plankton, fish, shellfish, wildlife,

plant life, shorelines, beaches, esthetics, and recreation which may

be expected from the presence of pollutants in any body of water,

including ground water; (B) on the concentration and dispersal of

pollutants, or their byproducts, through biological, physical, and

chemical processes; and (C) on the effects of pollutants on the

biological community diversity, productivity, and stability,

including information on the factors affecting rates of

eutrophication and rates of organic and inorganic sedimentation for

varying types of receiving waters.

Pursuant to section 304(a), EPA has developed to date, aquatic life

criteria guidance for 31 chemicals and human health criteria guidance

for 100 chemicals. For the most part, States and Tribes have found such

EPA criteria guidance useful in setting standards to protect designated

uses. Since 1980, most States and Tribes have adopted at least some of

the criteria guidance published by EPA pursuant to CWA section 304(a).

However, EPA\'s resources available to develop criteria guidance are

limited. Thus, there are cases where the scientific information or data

necessary to develop criteria exist but EPA has been unable to

establish section 304(a) criteria guidance.

States and Tribes may establish numeric criteria using CWA section

304(a) criteria guidance, section 304(a) criteria guidance modified to

reflect site-specific conditions, or other scientifically defensible

methods. 40 CFR 131.11(b)(1). There are situations where EPA relies on

the 304(a) criteria guidance when promulgating replacement standards

for a State or Tribe pursuant to section 303(c). EPA promulgation of

304(a) criteria for States or Tribes is discussed in more detail below.

Numeric criteria are values expressed as levels, concentrations,

toxicity units, or other numbers deemed necessary to protect designated

uses. Water quality criteria developed under Section 304(a) are based

solely on data and scientific judgments on the relationship between

pollutant concentrations and environmental and human health effects.

EPA criteria under section 304(a) do not reflect consideration of

economic impacts or the technological feasibility of meeting the

chemical concentrations in ambient water. As discussed below, 304(a)

criteria are used by States and Tribes to establish water quality

standards, and ultimately provide a basis for controlling discharges or

releases of pollutants.

Numeric criteria are important because they provide a proven

effective basis for implementation of the CWA. For example, these

criteria often form the basis for NPDES water quality-based permit

limits for point source dischargers and for establishing TMDLs for a

water body as a whole. Numeric criteria can also be useful in assessing

\[\[Page 36763\]\]

and managing nonpoint source pollution problems.

The Act uses the term \`\`criteria\'\' in two separate ways. In section

303(c), the term is part of the definition of a water quality standard.

That is, a water quality standard is comprised of designated uses, and

the criteria necessary to protect those uses. Thus, States and Tribes

are required to adopt regulations that contain legally enforceable

criteria. However, in section 304(a) the term \`\`criteria\'\' is used
in

the scientific sense. That is, under section 304(a), EPA develops

scientifically sound criteria guidance which may form the basis for

State, Tribal or Federal adoption of water quality standards pursuant

to section 303(c). Thus, two distinct purposes are served by the

section 304(a) criteria. The first is as guidance to the States and

Tribes in the development and adoption of water quality criteria that

will protect designated uses, and the second is as the basis for

promulgation of legally enforceable water quality criteria by the State

or Tribe, or via a superseding Federal rule when such action is

necessary.

As with all science, new information leads to new insights

concerning pollutant impacts on water quality. This ongoing evolution

affects two important and inter-related responsibilities of the Agency,

which are carried out concurrently. First, from time to time EPA

revises the 304(a) water quality criteria to reflect the latest data

and advances in criteria science. EPA compiles the current water

quality criteria guidance from time to time in a series of guidance

documents: the Green Book in 1968, the Blue Book in 1972, the Red Book

in 1976, and the Gold Book in 1986. The second responsibility pertains

to the requirements of section 303(c).

As part of the water quality standards triennial review process

defined in section 303(c)(1), the States and Tribes are responsible for

maintaining and revising water quality standards. Section 303(c)(1)

requires States and Tribes to review, and modify if appropriate, their

water quality standards at least once every three years. If EPA

determines that a new or revised standard is not consistent with the

requirements of the CWA, or EPA determines that a revised standard is

necessary to meet the requirements of the Act, Section 303(c)(4)

authorizes EPA to promulgate replacement water quality standards. From

time to time EPA has chosen to undertake such promulgations. In doing

so, EPA considers the most current available scientific information,

such as toxicity data and exposure assumptions.

With a number of Federal promulgations of water quality criteria

under section 303(c)(4) occurring over time, or the publication of a

new or revised 304(a) criteria guidance document, the criteria value(s)

in an earlier Federal action may differ from the value(s) in a

subsequent Federal action. This has led to some confusion among the

public with regard to what EPA\'s current section 304(a) water quality

criteria may be for a given chemical at any given time, and, what

values EPA would promulgate for a State or Tribe under section 303(c).

Currently, EPA interprets the most recent Federal action, whether taken

pursuant to 303(c) or 304(a), as establishing the current section

304(a) criteria guidance. When EPA determines that a Federal rule is

necessary to correct deficiencies in State criteria, EPA looks to the

most recent criteria science, as articulated in either section 304(a)

criteria guidance or EPA\'s most recent statement contained in a

proposed or final section 303(c) rule.

To date, the most recent Federal recalculation of section 304(a)

criteria occurred in the proposed California Toxics Rule (CTR)(62 FR

42160), July 30, 1997. The proposed CTR was undertaken pursuant to CWA

section 303(c)(2)(B). In the Water Quality Act of 1987, Congress

increased the emphasis on numeric criteria for toxic pollutants by

enacting section 303(c)(2)(B). This section requires all States and any

Tribe with water quality standards authority to adopt ambient water

quality criteria for toxics (priority pollutants) for which EPA has

published criteria under section 304(a), and for which the discharge or

presence could reasonably be expected to interfere with the designated

use adopted by the State or Tribe. In adopting such criteria, States

and Tribes must establish numerical values based on: (1) 304(a)

criteria; (2) 304(a) criteria modified to reflect site-specific

conditions; or, (3) other scientifically defensible methods.

Again, EPA views the criteria program as constantly evolving.

Whenever new or revised criteria are published, whether under 304(a) or

a rule under 303(c), that action establishes the Agency\'s most current

section 304(a) criteria guidance.

Whenever a State or Tribe revises its water quality criteria EPA

compares the State criteria values and the basis of their derivation to

the criteria contained in the most recent Federal action (either

303(c)(4) rule making or 304(a) criteria guidance publication). Thus,

there may be cases where the applicable policies and science have

evolved such that EPA would be comparing State or Tribe adopted

criteria values to Federal criteria values other than those in older

rules or criteria guidance to determine whether to approve the State\'s

or Tribes\'s criteria. This approach is necessary to encourage State and

Tribal adoption of the most recent section 304(a) criteria.

2\. Ambient Water Quality Criteria to Protect Aquatic Life

Aquatic life criteria are scientifically-derived values, derived by

States, Tribes, or EPA, to protect aquatic life from the deleterious

effects of pollutants in ambient water. States and Tribes may use EPA\'s

section 304(a) criteria guidance in developing such criteria. When

developing numeric aquatic life criteria, States and Tribes usually

express two concentrations; one that protects against acute effects

(effects from short term exposure) and one that protects against

chronic effects (effects from long term exposure). The short-term

concentration is expressed as a Criterion Maximum Concentration (CMC)

and is the highest ambient concentration of a toxicant to which aquatic

organisms may be exposed for a short time period without causing an

unacceptable effect. The long-term concentration is expressed as a

Criterion Continuous Concentration (CCC) and is the highest ambient

concentration of a toxicant to which aquatic organisms can be

continuously exposed without causing an unacceptable effect.

Water quality criteria to protect aquatic life consist of three

components\--magnitude, duration and frequency. Magnitude refers to the

acceptable concentration of a pollutant. Duration is the period of time

(averaging period) over which the ambient concentration is averaged for

comparison with criteria concentrations. Frequency is how often the

criteria can be exceeded to allow the aquatic community sufficient time

to recover from excursions of aquatic life criteria and to thrive after

recovery.

The numerical aquatic life criteria are expressed as short-term and

long-term concentrations in order that the criteria more accurately

reflect toxicological and practical realities. The combination of a

Criterion Maximum Concentration (CMC), over a one-hour acute duration

(a short-term average acute limit), and a Criterion Continuous

Concentration (CCC), over a four-day chronic duration (a long-term

average chronic limit) provide protection of aquatic life and its uses.

Recommended averaging periods are kept relatively short because

excursions higher than the average can

\[\[Page 36764\]\]

kill or cause substantial damage in short periods.

The frequency limitations specify that both the acute and chronic

criteria may be exceeded once in a three-year period on the average.

The recommended once in a three-year period coupled with the 4-day

chronic averaging period used for the CCC approximately corresponds to

the historically used criterion concentrations that occurs in a once-

in-ten year seven-day-average low flow (7Q10). The once-in-three-year

period coupled with the one-hour acute averaging period used for the

CMC approximately corresponds to the historically used criterion

concentration that occurs in a once-in-ten year one-day-average low

flow (1Q10)

The method by which EPA derives criteria is updated from time to

time, to incorporate advances in the science. To overcome the

limitations in the previous approaches to duration and frequency, a new

risk assessment methodology is being developed. EPA expects that the

new risk assessment methodology will include an approach that will

better handle variable concentrations by use of a kinetic-based

toxicity model coupled with a population response model. A kinetic-

based toxicity model considers the speed at which effects appear in

different individuals and at different concentrations. The kinetic-

based model allows prediction of the toxicity of any series of time-

variable concentrations. It can predict how often effects would occur,

and what fraction of individuals in the species would be affected.

To weigh the full impact that a particular time series of

concentrations would have on the exposed population of a species, an

additional factor is being considered: how long it takes to replace

those individuals lost due to the toxic effects. Consideration of this

involves the use of a population model indicating rates of recovery of

different taxonomic groups to stresses. The intent of this part of the

derivation is to allow the toxic impact to be portrayed as the overall

average reduction in the number of individuals in a species, both

during lethal or sublethal periods and during recovery periods,

accounting for both partial lethality and partial recovery.

Request for public comment on Aquatic Life Criteria

EPA requests comments on the following question:

1\. Prior to completion of all of the aquatic life methodology

revisions, should EPA use the tools that have thus far been developed

(the kinetic model of individual organism response to derive the

appropriate duration/averaging period of the criterion or to evaluate

mixing zone alternatives and the population effects model to derive the

allowable frequency of excursion above the criterion) to re-examine and

possibly revise its recommendations on the duration and frequency of

criteria excursions?

3\. Site-Specific Criteria

EPA also provides guidance on how States and Tribes may develop

site-specific numeric aquatic life criteria that are either more or

less stringent than the criteria adopted by the State or Tribe and that

would normally apply to a water body. Currently, national guidance only

has recommendations and methods for establishing site-specific water

quality criteria for aquatic life but guidance is under development for

deriving site-specific sediment quality criteria as well.

The regulation currently specifies that States and Tribes may adopt

numeric criteria based on published CWA section 304(a) guidance,

section 304(a) guidance modified to reflect site-specific conditions,

or other scientifically defensible methods. 40 CFR 131.11(b). EPA

recognizes that States and Tribes may want to develop numeric criteria

that vary from CWA section 304(a) guidance for specific waters (e.g.,

where chemical and physical characteristics of local waters alter the

bioavailability and/or toxicity of a pollutant; or when the species or

community actually present or desired may be more or less sensitive

than the species or community represented by the criteria database.) In

such situations, a site-specific criterion may be appropriate. EPA has

developed and continues to develop guidance to assist States and Tribes

in the development of site-specific criteria. (See Water Quality

Standards Handbook, Second Edition, EPA 823-B-94-005a, August, 1994, pp

3-38 through 3-45 and documents cited therein.)

Site-specific criteria are allowed by regulation and must be

submitted to EPA for review and approval, as are any changes to a WQS.

The regulation at 40 CFR 131.11(b)(1) specifically provides States and

authorized Tribes with the opportunity to adopt water quality criteria

that are \`\`\* \* \* modified to reflect site specific conditions.\'\'
Under

40 CFR 131.5(a)(2), EPA reviews State and Tribal standards to determine

\`\`whether a State has adopted criteria to protect the designated
uses\'\'

and whether such criteria are scientifically defensible (40 CFR

131.11(b)).

Existing guidance and practice are that EPA will approve site-

specific criteria developed on the basis of sound scientific

rationales.

Currently, EPA has specified three scientifically defensible

procedures that States and Tribes may follow in deriving site-specific

aquatic life criteria. These are the Recalculation Procedure, the

Water-Effect Ratio Procedure and the Resident Species Procedure. These

procedures can be found in the Water Quality Standards Handbook (USEPA,

1994). States may also develop other procedures for deriving such

criteria as long as they are scientifically defensible. EPA also

recognizes there may be naturally occurring concentrations of

pollutants that may exceed the national criteria guidance published

under Section 304(a) of the Clean Water Act.

The Great Lakes Guidance contains a procedure for developing site-

specific criteria for protection of wildlife. While the Great Lakes

States and Tribes must adopt a procedure consistent with that

procedure, other States and Tribes may derive site-specific criteria

using the procedure in the Great Lakes Guidance and such criteria can

be more or less stringent than the applicable wildlife criteria where

scientifically defensible. This is most likely to be in cases where a

site-specific Bioaccumulation Factor (BAF) has been developed.

The Great Lakes Guidance also provides a procedure for modifying

human health criteria on a site-specific basis based on differences in

fish consumption or BAF. With regard to aquatic life criteria, if a

State or Tribe could demonstrate that physical or hydrological

conditions preclude aquatic life from remaining at a site for a period

of time in which acute or chronic effects may occur, less stringent

site-specific aquatic life criteria are allowed.

EPA\'s current thinking is that States and Tribes should identify in

their water quality standards the methods they intend to use for site-

specific criteria development and generally the circumstances under

which such criteria may be developed. Additional discussion and request

for comment on emerging rationales and methods for site-specific

criteria, beyond that described and referenced above, is contained in

section B.4.d of this notice, entitled \`\`Alternatives to Removal of
the

Designated Use.\'\'

Request for Comments on Site-Specific Criteria

EPA seeks public comment on the following questions:

1\. Should the regulation be modified to require States and Tribes

to specifically authorize and identify the procedures for developing

site-specific water quality criteria? Would additional EPA guidance be

necessary?

\[\[Page 36765\]\]

2\. Should the regulation or EPA guidance specify the circumstances

under which site-specific criteria are necessary?

3\. Does EPA need to develop guidance, policy, or clarify the

regulation regarding site-specific criteria based on ambient

conditions?

4\. Should EPA explore broadening the concept of site-specific

criteria to include watershed-specific or ecosystem-specific criteria

perhaps in conjunction with a refined use designation? If so, what type

of additional guidance or policy is necessary to fully explain these

concepts and are any changes to the regulation needed to enable and/or

facilitate use of watershed or ecosystem-specific criteria?

4\. Narrative Water Quality Criteria

Narrative criteria can be an effective tool for controlling the

discharge of pollutants when numeric criteria are not available.

Narrative criteria, which have become known as \`\`free froms\'\', were

first developed in 1968 and continue to be used in State and Tribal

water quality standards. EPA guidance explains that these \`\`free

froms\'\' apply to all waters of the United States at all flow
conditions

(including ephemeral and intermittent streams) (see Water Quality

Standards Handbook: Second Edition (EPA-823-B-94-006, August 1994).

Narrative \'free from\' criteria guidance indicates that all waters be

free from substances, for example, that (a) cause toxicity to aquatic

life or human health, (b) settle to form objectionable deposits, (c)

float as debris, oil, scum and other materials in concentrations that

form nuisances, (d) produce objectionable color, odor, taste or

turbidity, or (e) produce undesirable aquatic life or result in the

dominance of nuisance species.

The toxic \`\`free froms\'\' include protection from both chronic and

acute toxicity and include all pollutants which cause toxic effects,

including but not limited to those listed under Section 307(a) if

necessary to protect the designated use. All States have adopted

narrative water quality criteria pursuant to section 303(c). See 48 FR

51400-51402, November 8, 1983. EPA guidance interprets these \`\`free

froms,\'\' as with all criteria, to apply to the ambient water quality,

not distinguishing between point sources and nonpoint sources of

toxicity.

Currently, 40 CFR 131.11(a)(2) of the water quality standards

regulation requires States and Tribes that have established narrative

criteria for toxic pollutants to identify the methods by which the

State or Tribe intends to regulate point source discharges of toxic

pollutants based on such narrative criteria. EPA regulations at 40 CFR

122.44(d)(1)(v) and (vi) require narrative criteria to be implemented

through NPDES permit limits. More specifically, when the permitting

authority determines that a discharge causes, has the reasonable

potential to cause, or contributes to an excursion above a narrative

criterion, the permit must, under most circumstances, contain effluent

limits for whole effluent toxicity. In addition, where the permitting

authority determines that a specific pollutant for which the State or

Tribe has not adopted a chemical criterion is in a discharge in an

amount that causes, has the reasonable potential to cause, or

contributes to an excursion above a narrative criterion, the permit

must contain effluent limits for that pollutant that are based on an

interpretation of the State\'s or Tribe\'s narrative criterion. The

regulation provides three options for interpreting the narrative

criterion, and in addition, EPA has provided guidance on this

requirement in both the Technical Support Document for Water Quality-

Based Toxics Control and the Water Quality Standards Handbook (both

Cited above). The guidance advises States and Tribes to develop

implementation procedures that explain the application and integration

of all mechanisms used by the State or Tribe to ensure that narrative

criteria are attained (e.g., chemical-specific requirements, whole

effluent toxicity requirements, and biological criteria, where

biological criteria programs have been developed by the State or

Tribe). The rationale for this approach is that comprehensive written

procedures facilitate implementation decisions, reduce inconsistencies

that can result in different requirements for similar situations, and

promote effective and sensible application of narrative toxics

criteria.

Although all States and Tribes have some type of customary practice

for implementing narrative criteria, and many States and Tribes have

developed implementation policies on narrowly defined topics (e.g., to

explain application of whole effluent toxicity testing requirements),

very few, if any, States and Tribes have developed comprehensive

written implementation procedures that address all of the narrative

toxics criteria implementation issues. The result may be inconsistent

application of narrative toxics requirements within those States and

Tribes that have not developed such procedures. In addition, the lack

of documented methods makes it difficult for EPA to evaluate whether

aquatic life and or human health is being adequately protected.

Request for Comments on Narrative Criteria

EPA seeks public comment on the following questions:

1\. Should the regulation require adoption of \`\`free froms\'\' and

similar criteria as being the minimum floor allowable under the Clean

Water Act.

2\. Reflecting current practice, should the regulation specify that

States and Tribes are required to adopt narrative criteria for all

waters?

3\. At this time, EPA has limited information about how States and

Tribes are implementing narrative criteria with regard to nonpoint

source activities. How can narrative criteria best be implemented in

the nonpoint source context and what might EPA do, including modifying

the regulation, to enhance or further the use of narrative criteria?

4\. Does the existing requirement for States and Tribes to identify

methods for implementing narrative toxics criteria need to be

clarified, and if so, should EPA clarify the requirement with

additional guidance, or with revisions to the regulation?

5\. What minimum elements should be included in an implementation

method for narrative toxics criteria? Should implementation methods

describe application and integration of all of the various mechanisms

used to regulate point sources, or should such methods focus on only

certain aspects of toxics control (e.g., chemical-specific limits,

whole effluent toxicity limits)?

6\. The current regulation requires the State or Tribe to identify

the method by which the State or Tribe intends to regulate point source

discharges of toxic pollutants on water quality limited segments based

on such narrative criteria.

Should this narrative criteria translation method apply only to

point source discharges of toxic pollutants on water quality limited

segments or to both point and non-point sources?

7\. Should the regulation more explicitly require implementation

procedures for narrative criteria other than toxics criteria? Should

the regulation include minimum requirements for these implementation

procedures?

5\. State or Tribe Derived Criteria

States and Tribes may develop their own criteria although the water

quality standards regulation 40 CFR 131.11 provides that where such

criteria are less stringent than 304(a) criteria

\[\[Page 36766\]\]

guidance, the State or Tribe must demonstrate the criteria are

scientifically defensible. Despite this available flexibility, and for

a variety of reasons, most States and Tribes are reluctant to derive

their own criteria. EPA is evaluating whether either changes to the

water quality standards regulation or development of additional

guidance would assist State or Tribal efforts to develop protective

criteria. For example, for many pollutants where EPA criteria guidance

has not been issued, information is available which would be useful in

determining a protective water quality criterion. Sources of such

information include relevant scientific literature, EPA\'s Integrated

Risk Information System (IRIS), EPA\'s Aquatic Toxicity Database

(AQUIRE), a database of high quality aquatic life toxicity data (under

development), and other sources.

Request for Comment on State or Tribal Derived Criteria

EPA requests comment on the following question:

1\. Would changes to the water quality standards regulation or

development of additional guidance assist State or Tribal efforts to

derive criteria? What changes or guidance would be most helpful?

6\. Water Quality Criteria for Priority Pollutants

EPA has not revised the water quality standards regulation to

incorporate CWA section 303(c)(2)(B) which was added to the CWA in

1987\. EPA has, however, issued guidance on how States and Tribes may

comply with section 303(c)(2)(B). The \`\`Guidance for State

Implementation of Water Quality Standards for CWA Section

303(c)(2)(B):December, 1988\'\' provides three options for compliance:

Option 1 States and Tribes may adopt Statewide or Reservation-wide

numeric chemical-specific criteria for all priority toxic pollutants

where EPA has issued CWA section 304(a) criteria guidance.

Option 2 States and Tribes may adopt numeric chemical-specific

criteria for those stream segments where the State or Tribe

determines that the priority toxic pollutants for which EPA has

issued CWA section 304(a) criteria guidance are present and can

reasonably be expected to interfere with designated uses.

Option 3 States or Tribes may adopt a chemical-specific translator

procedure that can be used to develop numeric criteria as needed.

The phrase \`\`translator procedure\'\' in this context means a method

for translating a State\'s or Tribe\'s narrative toxics criterion into

chemical-specific, numeric criteria sufficient to comply with CWA

section 303(c)(2)(B). As discussed in EPA guidance (\`\`Guidance for

State Implementation of Water Quality Standards for CWA Section

303(c)(2)(B),\'\' December 1988, Notice of Availability at 54 FR 346,

January 5, 1989), such translator procedures generally identify the

equations, protocols, and data sources that are used to translate

narrative criteria into derived chemical-specific criteria. Such

translator procedures are different from the narrative criteria

implementation procedures required in 40 CFR 131.11(a)(2) of the water

quality standards regulation in that such implementation procedures

must be adopted into the State\'s or Tribe\'s regulations and generally

describe all mechanisms that are used and integrated to attain

narrative criteria, including chemical-specific, whole effluent

toxicity, and biological methods (see the discussion of narrative

criteria implementation procedures in sub-section (c)(6) above). EPA

believes that revisions to the water quality standards regulation to

incorporate the CWA section 303(c)(2)(B) requirements would enhance

public understanding of EPA\'s implementation of the provision.

EPA\'s guidance on CWA section 303(c)(2)(B) established a

presumption that any information indicating that such pollutants are

discharged or present in surface waters (now or in the future) may be

considered sufficient justification to require adoption or derivation

of numeric criteria. The guidance made clear that the requirement to

adopt (or derive) criteria applies not just to pollutants that are

already affecting surface waters, but also to pollutants that have the

potential to affect surface waters in the future. The rationale for

this approach is that it is important to have numeric criteria applied

to waters where current or future activities may result in sources of

priority toxics that warrant regulatory controls or other pollution

abatement or assessment activities. This interpretation of section

303(c)(2)(B) is now reflected in EPA guidance included in the Technical

Support Document (TSD) for Water Quality-Based Toxics Control (TSD) and

the Water Quality Standards Handbook (see page 30 in the TSD).

In implementing CWA section 303(c)(2)(B), many States and Tribes

have adopted statewide or reservation-wide criteria for all priority

toxics where EPA has issued CWA section 304(a) criteria guidance.

Taking this approach eliminates the need to determine whether a

\`\`reasonable expectation\'\' for use interference exists on a water
body-

by-water body basis, and thus greatly simplifies the process for

establishing numeric criteria for priority toxics. In other States and

Tribes, however, broad application of numeric criteria for priority

toxics has not occurred, and the \`\`reasonable expectation\'\' question

has been a significant implementation issue. EPA is considering whether

its existing guidance on this issue is adequate to support equitable

decisions nationally.

Another issue stemming from CWA section 303(c)(2)(B) implementation

concerns the State or Tribe option to develop a \`\`translator

procedure\'\' to achieve compliance. In EPA\'s CWA section 303(c)(2)(B)

guidance, this approach was described as Option 3. The guidance

intended to be used are the 1980 Human Health Guidelines and 1985

Aquatic Life Guidelines. All of which have been both peer reviewed and

publicly reviewed and thus meet the requirements of \`\`scientific

defensibility\'\' under 40 CFR 131.11.

Although EPA believes that adoption of such chemical-specific

translator procedures potentially provide a State or Tribe with a

useful means of establishing criteria, there are several issues

associated with the use of such procedures. For example:

\(1\) It may be difficult for the public to stay abreast of the

current applicable criteria where a State or Tribe does not routinely

publish an updated list of State or Tribe criteria and provide wide

distribution.

\(2\) Public participation may occur primarily on the details of the

procedure itself, rather than the pollutant-specific criteria resulting

from application of the procedure.

\(3\) Without requirements to submit to EPA for review and approval

the individual criteria generated using the translator procedure, there

could be a tendency to not include such criteria in the State\'s or

Tribe\'s water quality standards at the time they are generated.

A third issue that arises from State and Tribal efforts to

implement CWA section 303(c)(2)(B) concerns the provision for priority

toxic pollutants that are not the subject of CWA section 304(a)

criteria guidance. Where such numeric criteria guidance is not

available, and where necessary to protect the designated uses, CWA

section 303(c)(2)(B) provides that when a State or Tribe (1) reviews

Water Quality Standards or (2) revises or adopts new standards pursuant

to this paragraph, States and Tribes are to adopt criteria based on

biological monitoring or assessment methods.

When adopting criteria based on biological monitoring or assessment

methods, States and Tribes currently

\[\[Page 36767\]\]

have considerable latitude to devise an approach to satisfy the

requirement. For example, States and Tribes may establish ambient

criteria for the parameter toxicity. Alternatively, States and Tribes

could adopt narrative biological criteria. Clearly, a variety of

approaches, representing a range of resource commitments, may be used

to satisfy this requirement. All of these approaches must meet the test

of \`\`scientific defensibility\'\' and be consistent with the goals of
the

CWA.

Request for Comments on Water Quality Criteria for Priority Pollutants

EPA seeks public comment on the following questions:

1\. With regard to compliance with section CWA section 303(c)(2)(B),

would it be better to include only a general requirement, such as one

which repeats the language in the statute itself, or should the

regulation reflect EPA\'s interpretation of the options to achieve

compliance with the provision?

2\. Have problems or issues arisen in the implementation of CWA

section 303(c)(2)(B) that may need to be addressed by changes in the

regulation or revised EPA guidance?

3\. What factors should be considered in determining whether a

\`\`reasonable expectation\'\' for use interference exists? How has the

\`\`reasonable expectation\'\' threshold decision been interpreted and

addressed by the States or Tribes? Does EPA need to clarify when a

\`\`reasonable expectation\'\' for use interference exists, and if so,

should the Agency clarify the requirement by issuing additional

guidance, by issuing regulatory requirements, or a combination of the

two approaches?

4\. Where a State or Tribe adopts a chemical-specific translator

procedure for derivation of numeric criteria, what process should the

State or Tribe follow to ensure that notice of State derived criteria

is provided to the public?

5\. Should EPA require States or Tribes using translator procedures

to publish an updated list of criteria for all water bodies?

6\. Should EPA revise the regulation to explicitly require that,

where a translator procedure is used to derive criteria, public

participation is required for each individual criterion, even where an

opportunity for public participation was previously provided when the

procedure itself was adopted?

7\. Should submission of each criterion derived using translator

mechanisms for review and approval or disapproval be a requirement,

even where EPA previously reviewed and approved the procedure itself?

If so, should implementation of derived criteria (e.g., in NPDES permit

renewal and development) proceed even where EPA has not yet issued an

approval/disapproval decision?

8\. Does this statutory provision need to be further clarified and

interpreted by the Agency? Should changes to the water quality

standards regulation or Agency guidance be pursued?

7\. Criteria for Non-Priority Pollutants with Toxic Effects

Over the years, an issue which has periodically arisen,

particularly for non-priority pollutants, has been the proper approach

to identifying the circumstances for which adoption of numeric criteria

is required. Currently, the regulation does not elaborate on how this

question should be addressed; it only provides the general mandate to

adopt criteria \`\`sufficient to protect uses.\'\'

EPA\'s current thinking is that the regulation should probably be

modified to further specify the circumstances under which numeric

criteria for non-priority pollutants must be adopted. One approach

would be to model the requirements for non-priority pollutants after

the requirements included in CWA section 303(c)(2)(B) for priority

pollutants. That is, for non-priority pollutants where EPA has issued

criteria guidance, the regulation could require adoption of numeric

chemical-specific criteria where the discharge or presence of the

pollutant can reasonably be expected to interfere with designated uses.

EPA could define \`\`reasonable expectation\'\' broadly to support
adoption

of criteria before new pollution sources are proposed, or more narrowly

for non-priority pollutants, limiting such a requirement for adoption

of criteria to only those water bodies and pollutants where uses are

already being interfered with, or where pollution sources now exist or

are certain to occur in the near future. Establishing Such a

requirement would encourage development of criteria for commonly-

discharged and highly toxic pollutants like ammonia and chlorine that

are currently not considered priority pollutants under section 307(a)

of the CWA.

Strengthening the requirements for adoption of criteria for non-

priority pollutants would address a concern of some that many of the

CWA section 307(a) priority pollutants are no longer an appropriate

focal point for State, Tribe and EPA toxic control efforts (e.g., some

of the pesticides included on that list are no longer in widespread

use).

Request for Comments on Criteria for Non-Priority Pollutants With Toxic

Effects

EPA seeks public comment on the following questions:

1\. For what specific pollutants and under what circumstances should

adoption of criteria for non-priority pollutants be required by

regulation?

2\. Should EPA amend the water quality standards regulation or issue

additional guidance to clarify when adoption of numeric chemical-

specific criteria for non priority pollutants is necessary to
\`\`protect

designated uses\'\'?

3\. Should EPA require States or Tribes to adopt narrative criteria

and a narrative criteria translation method for both 307(a) and other

pollutants which elicit toxic effects on organisms?

8\. Criteria Where Data or Guidance is Limited

A key issue facing States and Tribes seeking to develop aquatic

life and human health criteria concerns the data requirements necessary

to support derivation of a criterion. (In developing national CWA

section 304(a) criteria guidance, EPA has established minimum data

requirements.) When sufficient, acceptable data are not available,

however, many States and Tribes have resorted to adoption of lowest

observed effect levels (LOELs) as criteria in order to ensure that some

level of protection is in place. LOELs are based on the lowest observed

concentration of a chemical at which a statistically significant

adverse effect was observed in an aquatic test organism. However, EPA

would counsel against adoption of water quality criteria based on LOELs

alone because they may not ensure protection of aquatic life uses

since: (1) they represent effect concentrations, and (2) there may be

significant limitations in the database upon which they are supported.

Thus, if this approach is used, States and Tribes are encouraged to

use safety factors to approximate better a protective water quality

level. The particular safety factor employed generally depends on the

amount and quality of data concerning the LOEL. EPA has approved this

approach in particular instances because criteria based on such LOELs

provide more protection than no criteria at all.

A better approach to developing values with sparse data was

developed and promulgated by EPA as part of the Water Quality Guidance

for the Great Lakes System (Great Lakes Guidance). Under that

Guidance\'s Tier II procedure, States and Tribes derive values to

interpret the narrative criteria for

\[\[Page 36768\]\]

pollutants where the minimum data requirements for derivation of a

criterion are not satisfied (see appendix C of 40 CFR Part 132.) These

values are then used in place of the absent criteria as the basis for

NPDES permit limits where needed. EPA\'s current thinking is that this

approach for establishing values for interpreting the narrative for

pollutants where data are limited is preferable to adoption of criteria

based on a LOEL.

The Tier II methodology in the Great Lakes Guidance is designed to

be used in the absence of the full set of data needed to meet criteria

data requirements. For pollutants for which criteria have not been

adopted into State or Tribal water quality standards, Great Lakes

States must, under the guidance, use methodologies consistent with

either the criteria (GLI Tier I) or Tier II methodologies, depending on

the data available to implement their existing narrative water quality

criteria that prohibit toxic pollutants in toxic amounts in all waters.

In adopting the Great Lakes Tier II methodology, EPA, working with

the States, determined that there is a need to regulate pollutants more

consistently in the Great Lakes System when faced with limited data on

which to base criteria. Many of the Great Lakes States are already

employing procedures similar to the approach in the final Guidance to

implement narrative criteria. EPA determined the Tier II approach

improves upon existing mechanisms by utilizing all available data. The

Tier II aquatic life methodology is used to derive Tier II values which

can be calculated with fewer toxicity data than under the Tier I water

quality criteria methodology. Tier II values can, in certain instances,

be based on toxicity data from a single taxonomic family, provided the

data are acceptable. The Tier II methodology generally produces more

stringent values than the Tier I criteria methodology, to reflect

greater uncertainty in the absence of additional toxicity data. As more

data become available, the derived Tier II values tend to become less

conservative. That is, they more closely approximate Tier I numeric

criteria.

States and Tribes may also develop their own criteria derivation

procedure under option 3 of EPA\'s CWA section 303(c)(2)(B) guidance for

priority toxic pollutants. This approach allows for timely derivation

of criteria based on the latest available data, and may be used to

derive criteria for pollutants for which EPA has not issued guidance.

However, as for all criteria, such a procedure would need to result in

criteria that are scientifically defensible, so again the issue of

minimum data requirements is important.

Request for Comment on Criteria Where Data or Guidance is Limited

EPA requests comment on the following questions:

1\. Should adoption of a lowest observed effect concentration be

considered an acceptable option where no other criteria guidance is

available, or should use of an uncertainty factor (e.g., 0.1, 0.5) be

required to better approximate a protective water quality level? If an

uncertainty factor is used, should that factor vary based on the amount

and quality of data used to drive the LOEL? If so how?

2\. Should EPA develop a method for derivation of alternative values

for pollutants where the minimum data requirements included in EPA\'s

criteria guidelines are not satisfied, such as the tier 2 procedure in

EPA\'s Water Quality Guidance for the Great Lakes System?

3\. How applicable should the Tier 2 process be to States and Tribes

outside of the Great Lakes? Does the regulation need to be modified to

include Tier 2 specifically for the entire country?

4\. Does the information included in EPA\'s toxicity databases (e.g.,

IRIS, AQUIRE) need to be made more accessible to States, Tribes, or

others seeking to develop their own criteria? If so, how can this be

accomplished?

9\. Toxicity Criteria

Toxicity criteria are an additional type of water quality criteria

used to protect aquatic life. Toxicity criteria are expressed in terms

of \`\`toxic units\'\' that cause toxic effects to aquatic organisms and

are determined by exposing aquatic organisms to water samples (e.g.,

ambient water or effluent discharges). Whole effluent toxicity (WET)

testing can be effective for controlling discharges containing multiple

pollutants. It can also provide a method for addressing synergistic and

antagonistic effects on aquatic life.

EPA is considering revising the water quality standards regulation

to require States and Tribes with water quality standards authority to

develop a numeric quantification of acceptable surface water levels for

the parameter \`\`toxicity.\'\' Doing so would implement the narrative

criteria that waters be \`\`free from\'\' toxics in toxic amounts.

Currently, States and Tribes use various approaches to implementing

their narrative criteria, including using numeric toxicity values and

implementing them through NPDES permits. However, there is no current

requirement for States or Tribes to specify numeric criteria for

toxicity in their water quality standards. Under current requirements

and guidance, States and Tribes do not always specify implementation of

toxicity criteria and test methods as a required means to implement the

narrative water quality criteria.

Toxicity is commonly measured by exposing test organisms (e.g.

Ceriodaphnia, Fathead minnow) to various concentrations of chemicals or

chemical mixtures in water. EPA has promulgated methods for measuring

aquatic toxicity in effluents and surface waters in 40 CFR Part 136.

EPA provided a recommendation on the allowable magnitude of this

parameter in the 1991 Technical Support Document for Water Quality-

based Toxics Control (TSD) that would facilitate State or Tribal

implementation of such a requirement. The recommendation reads: For

protection against acute toxicity, \`\`the criterion maximum

concentration (CMC) should not exceed 0.3 acute toxic units to the most

sensitive of at least 3 test species; for chronic protection, the

criterion continuous concentration (CCC) should not exceed 1.0 chronic

toxic units to the most sensitive of at least 3 test species.\'\' Such a

quantification serves, in conjunction with numeric criteria for

individual pollutants and biological criteria, to establish an

integrated and fully protective basis for assessment and control of

pollutants.

Request for Comment on Toxicity Criteria

EPA seeks public comment on the following question:

1\. Should the regulation be modified to explicitly require States

and Tribes to adopt numeric toxicity criteria, or alternatively to use

toxicity values and test methods as a required means to interpret and

implement the narrative criteria? Or, is the current practice

acceptable, whereby some States or Tribes have numeric toxicity

criteria, some utilize toxicity methods to interpret their narrative

requirements of no toxics in toxic amounts, and others use toxicity

mainly as a tool to assess effluent quality, but not as the basis for

permit limits?

10\. Sediment Quality Criteria

Sediment quality criteria (SQC) are being developed by EPA pursuant

to sections 304(a)(1) and 118(c)(7)(C) of the CWA in recognition that

many water bodies are not meeting water quality goals even though

ambient water quality criteria are being met. (See \`\`The Incidence and

Severity of Sediment Contamination in Surface Waters of the

\[\[Page 36769\]\]

United States, Volume 1: National Sediment Inventory,\'\' Office of

Science and Technology, September 1997, EPA-823-R-97-006.) The

contaminants of interest are those that preferentially partition to

sediments, become sequestered, and remain bioavailable to the aquatic

community. SQC are intended to protect against chronic effects to

benthic organisms resulting from sediment contamination. The

development and implementation of SQC is intended primarily to enable

development of pollutant-specific State standards and NPDES permit

limits needed for implementation of a more effective source control

program. In addition, SQC will be useful in other programs, such as

developing clean-up levels for sediment remediation activities and in

evaluating sediments dredged from the Nation\'s waterways.

Sediment quality criteria have been proposed for five non-ionic

organic compounds: acenapthene, dieldrin, endrin, fluoranthene, and

phenanthrene. See, Technical Basis for Deriving Sediment Quality

Criteria for Nonionic Organic Contaminants for the Protection of

Benthic Organisms by Using Equilibrium Partitioning (EPA-822-R-93-011);

Acenapthene (EPA-822-R-93-013); Dieldrin (EPA-822-R-93-015); Endrin

(EPA-822-R-93-016); Fluoranthene (EPA-822-R-93-012); Phenanthrene (EPA-

822-R-93-014). In addition to non-ionic organic compounds, the Agency

also is working to develop SQC for metals. After considering public

comments, EPA intends to publish final SQC dieldrin and aldrin in final

form. The proposed criteria for acenapthene, fluoranthene, and

phenanthrene will not go final; instead, EPA plans to propose a total

PAH sediment criterion. In addition to its work on SQC, the Agency also

is working to develop standardized methods for performing chronic

sediment bioassay tests.

The EPA Science Advisory Board subcommittee reviewing SQC for non-

ionic organics concluded that: \`\`these criteria not be used as stand-

alone, pass-fail values for all applications.\'\' (EPA-SAB-EPEC-93-002).

EPA is developing a users manual to provide guidance on use of SQC in a

regulatory context to ensure consistency with that recommendation. The

guidance would recommend that SQC be used in conjunction with chronic

sediment bioassay tests in determining compliance with State standards,

such as in interpreting the narrative criterion of no toxics in toxic

amounts. Such an approach is currently being developed in more detail,

and the users guidance will be made available to the public for comment

prior to being finalized.

Request for Comment on Sediment Quality Criteria

EPA seeks public comment on the following questions:

1\. Should the current regulation be revised to specifically address

sediment quality criteria, and if so, what should such revisions

address?

2\. What chemicals or classes of compounds should receive priority

for development of SQC?

11\. Biological Criteria

Biological Integrity, Assessments and Criteria \'

The Clean Water Act directs EPA to work with States and Tribes to

restore and maintain the biological integrity of the Nation\'s surface

waters (CWA 101(a), 303, 518(e)). Biological integrity is defined as a

balanced, integrated, adaptive community of organisms having a species

composition, diversity, and functional organization comparable to that

of the natural habitat of a region (Karr and Dudley, EPA-440/5-90-004,

1981). Biological integrity does not necessarily represent an aquatic

system untouched by human influence, but does represent one that is

balanced, adaptive and reflects natural evolutionary processes.

Designated uses and criteria to protect those uses in State and Tribal

water quality standards programs provide the means to achieve

biological integrity.

To more fully protect aquatic resources and provide more

comprehensive assessments of aquatic life use attainment, it is EPA\'s

policy that States and Tribes should designate aquatic life uses for

their waters that appropriately address biological integrity and adopt

biological criteria necessary to protect those uses (EPA-823-B-93-002,

Office of Water Memorandum to EPA Regions, Policy on Bioassessment and

Biological Criteria, 1991). Designated uses to support aquatic life can

cover a broad range, or continuum, of biological conditions with some

waters being closer to the ideal of biological integrity than others.

The attainable levels of biological integrity for any water is a State

and/or Tribal determination involving public participation.

For example, the State of Maine used the water quality

classification law to establish the minimum standards for three levels

of biological integrity. These levels correspond to the water quality

classification system and are increasingly restrictive, proceeding from

the minimum state standard, Class C, to Class A, the most protective

standard. These refinements serve to explicitly specify the designated

aquatic life uses that apply to each classification category. Class C

requires that the structure and function of the biological community be

maintained and provides for the support of all indigenous fish species.

The intermediate standard of Class B requires that there be no

detrimental changes to the aquatic community, that all indigenous

species are supported and that habitat be unimpaired. The Class A

standard requires that aquatic life be \`\`as naturally occurs\'\' and

habitat be characterized as \`\`natural.\'\' Within Class A, there is
even

a subset, Class AA, that further specifies \`\`free-flowing\'\' habitat.

Waters with the Class AA designation are protected from any additional

discharge or alteration. Under this system, attainment of the aquatic

life classification standards for a given water body is evaluated using

numeric biological criteria that were statistically derived from a

statewide database. The numeric biological criteria are slated to go to

rule-making in 1998.

Biological assessments are used to evaluate the condition of a

water body using direct measurements of the resident biota in surface

waters. Biological assessments integrate the cumulative impacts of

chemical, physical, and biological stressors on aquatic life.

Biological criteria, derived from biological assessment information,

can be used to define State and Tribal water quality goals for aquatic

life by directly characterizing the desired biological condition for an

aquatic life use designation. Biological criteria are narrative

descriptions or numerical values that describe the reference condition

of the aquatic biota inhabiting waters of a specific designated aquatic

life use (EPA-440/5-90-004). Biological criteria are based on

integrated measures, or indices, of the composition, diversity, and

functional organization of a reference aquatic community. The reference

condition describes the attainable biological conditions for water body

segments with common characteristics within the same biogeographic

region. In summary, biological criteria provide a direct measure of the

desired condition of the aquatic biota. This capability serves a dual

purpose\--goal setting and environmental impact analysis. Biological

assessments are then conducted to evaluate if a water body is attaining

its designated aquatic life use.

Biological criteria can play an important role in water quality

programs and when properly implemented, complement and support

\[\[Page 36770\]\]

other methods and criteria, such as chemical water quality criteria and

whole effluent toxicity criteria. The latter are measures, or

indicators, of environmental stress and exposure whereas the biological

assessments and criteria measure the cumulative effects of stressors on

the aquatic community, whether chemical, physical or biological

stressors, singly or in combination. A water quality program that

employs the full array of methods and criteria will develop the

information needed for more accurate assessment of impairment and

effective resource management.

The linkage of biological effects, stressor identification and

exposure assessment is particularly important when there are multiple

stressors impacting a water body, especially when a watershed

management approach is taken, or where wet weather flows are a major

source of impairment in the water body. A comprehensive water quality

program with biological, chemical, toxicity, and physical components

will enable States and Tribes to make better decisions and focus

limited resources to maximize environmental gain. A critical issue

facing EPA\'s National Water Program is the manner and extent to which

biological assessments and criteria should be incorporated into water

quality programs to transition to a more comprehensive water quality

control program that will better identify impairments and track

improvements. This includes integrating biological assessments and

criteria into use designations and attainability analyses, watershed

management strategies and source control requirements.

Biological criteria typically include measures of the types,

abundance, and condition of aquatic plants and animals, providing

information on the status and function of the aquatic community in

response to the cumulative impact of both chemical and nonchemical

stressors. For example, Ohio uses a multi metric approach to develop

numeric biological criteria for two different assemblages: benthic

macro invertebrates (bottom dwelling insects, etc.) and fish (Yoder,

1995). Biological indices have been derived that integrate measurable

structural and functional characteristics of the in-stream fish and

macro invertebrate communities which help assess the health of the

community. Structural characteristics are based on measures of

biological community structure such as diversity or taxa richness (e.g.

total number of taxonomic groups) and the representation of specific

taxonomic groups (e.g. number of mayfly or caddisfly taxonomic groups)

within the community. Functional characteristics include measures of

biological function such as feeding strategy (e.g. percent carnivores,

omnivores), environmental tolerance (e.g. number of intolerant and

tolerant species), and disease symptoms (e.g. percent diseased species

and anomalies, including deformities, eroded fins, lesions and external

tumors in fish).

The Ohio biological criteria were developed based on ecoregional

reference conditions and provide a quantitative biological description

of the State\'s designated aquatic life uses for warm water rivers and

streams, including exceptional, general, modified and limited warm

water habitat. The description and derivation of the indices and

ecoregions are contained in the \`\`Biological Criteria for the

Protection of Aquatic Life: Volume II. Users Manual for Biological

Field Assessment of Ohio Surface Waters\'\' cited in Ohio\'s Water
Quality

Standards. Ohio uses biological criteria to support all aspects of its

water quality management program (Yoder, 1995). Ohio\'s approach is

another example of how a State can adopt biologically-based refined

designated aquatic life uses and biological criteria consistent with

EPA\'s policy.

Application of Biological Assessments and Criteria in State and Tribal

Water Programs

Biological assessments and criteria can be an important component

of State and Tribal watershed management programs by assisting in

prioritization and targeting of actions, setting restoration goals and

performance standards, and documenting results. For example, North

Carolina has adopted narrative biological criteria into its water

quality standards regulation that references standardized methods for

data collection and analysis for fish and macro invertebrate

communities. Specific biological indices, metrics, or numeric criteria

are not included in the water quality standards regulation. However, by

citing the standardized methods in the State\'s water quality standards,

North Carolina established a mechanism for consistent, quantitative

translation of the narrative biological criteria. Under the State\'s

five year basin-wide management program, benthic macro invertebrate and

fish community data are presented in individual basin-wide assessment

reports. Macroinvertebrate and fish community surveys, special studies,

and other water quality sampling activities are conducted in the second

and third years of the cycle to provide information for assessing

status and trends through the basin. Water quality management plans are

being developed for all of the State\'s major river basins on five year

cycles.

Biological assessments and criteria can fulfill several assessment

functions within the NPDES permitting process. In conjunction with

pollutant concentration and toxicity data, biological assessments can

be used to detect previously undetected chemical water quality problems

and to evaluate the effectiveness of control actions. Biological

findings of use impairment can trigger the necessary technical

investigations which can identify the source or sources of impairment

and determine appropriate corrective measures through point or nonpoint

source controls as appropriate. The State of Maine uses biological

assessments and criteria to evaluate the effectiveness of controls and

to inform the permit review process. Aquatic life criteria are

specified in the water quality classification law and attainment is

assessed using quantitative data and a multi variate statistical model.

Findings of biological impairment trigger management intervention to

identify possible causes. Permits have been modified and enforcement

actions initiated to address biological impacts. Alternatively,

favorable biological findings have been used in a tiered approach to

re-direct limited agency and permittee resources to more urgent

concerns.

In Maryland, investigators use bioassessments as an integral part

of the Rapid Stream Assessment Technique (RSAT) to conduct watershed-

wide stream quality reconnaissance, rapid screening of general storm

water BMP performance and for elucidating general watershed land use\--

stream quality relationships (Galli, J., 1997). In Michigan, biological

assessments have been used in the Wayne County Rouge River National Wet

Weather Demonstration Project to identify impacts and to guide

decision-makers and the public in evaluating options for preventing,

reducing and minimizing pollution loading impacts on the river under a

watershed approach to wet weather pollution management (Cave, 1997).

Biological assessments and criteria can be useful in evaluating

highly variable or diffuse sources of pollution such as storm water

runoff. These types of point source pollution do not lend themselves

well to traditional chemical water quality monitoring and a biological

assessment of their cumulative impact may effectively evaluate these

discharges and the success of control actions.

\[\[Page 36771\]\]

Bioassessments have been successfully used in Florida to assess the

cumulative impacts of multiple pollution sources within a watershed, in

particular, storm water runoff and other nonpoint source discharges

(McCarron, Livingston and Frydenborg, 1997). The Florida Storm water/

Nonpoint Source Bioassessment Projects have found that bioassessments,

over time, help reflect impacts from the fluctuating environmental

conditions and highly variable pollutant inputs of wet weather

discharges. Bioassessments also help to evaluate the habitat

degradation typically associated with Storm water discharges.

Bioassessments were also identified by key storm water experts from

across the Nation as an important environmental indicator tool for

assessing the impacts of storm water runoff and the effectiveness of

storm water management strategies (Claytor and Brown, 1996).

When attempting to identify the specific sources of use impairment

(stressors), the role that biological assessments and criteria will

play needs to be carefully defined. Stressor identifications based

solely on biological information may be straightforward in certain

water bodies where a single source is the cause of impairment. In these

cases, paired bioassessments, conducted above and below the discharge

point, or in the vicinity of the source, may readily identify the

degree of impairment and the efficacy of chosen control strategies. In

small urban watersheds, dominated by storm water runoff, bioassessments

and criteria may provide a direct means to measure and control the

storm water impacts.

However, in complex water bodies, where numerous sources contribute

to the observed biological impairment, it may be difficult for

bioassessments to distinguish the relative degrees of impairment from

each contributing source. Given these situations, EPA anticipates that

a stressor identification evaluation (SIE) procedure will need to be

developed to provide the technical tools and information that watershed

managers can use to identify and evaluate the different sources of

impairment that the bioassessments reveal and the specific stressors

associated with each source (e.g. flow, turbidity, temperature, metals,

etc.).

Guidance on Development of Biological Criteria

EPA has developed and will continue to develop technical guidance

on conducting bioassessments and developing biological criteria for the

following specific water body types: streams and wadable rivers, lakes

and reservoirs, estuaries and near coastal waters, wetlands and large

rivers. Technical guidance for streams and small rivers biological

assessments and criteria was published in 1996 (EPA 822-B-96-001).

Publication of technical guidance on lakes and reservoirs is expected

in 1998 followed by guidance on estuaries and near coastal waters by

1999\. Technical guidance development for wetlands was initiated in 1997

and for large rivers in 1998. Completion of these documents is planned

within 5 years.

Guidance on Implementation of Biological Criteria

EPA is currently considering how to best advance State and Tribal

adoption and implementation of biological criteria. A draft discussion

document on implementation of biological criteria by States and Tribes

sets forth an iterative, step-wise approach to development of

biological criteria and adoption in State and Tribal water quality

standards. (draft guidance document on biological criteria

implementation, EPA, March 1998) Elements of a stepwise approach could

include:

\(1\) establishment of a long term goal to restore and maintain

biological integrity of State or Tribal surface waters where determined

feasible;

\(2\) implementation plan for development of biological criteria for

specific water body types, including time frame;

\(3\) development of standardized biological assessment methods,

regional reference conditions, and biological database to support

refinement of designated aquatic life uses and development of

biological criteria;

\(4\) adoption of narrative biological criteria into water quality

standards;

\(5\) adoption of quantitatively-based biological criteria in water

quality standards.

In developing a flexible, stepwise approach, EPA is evaluating

options for adoption of biological criteria that would result in the

consistent translation of narrative biological criteria into numeric

criteria (e.g. quantitatively-based biological criteria). A

quantitatively-based biological criteria could be defined as:

\(1\) A narrative statement adopted into State or Tribal water

quality standards that describes specific designated aquatic life uses

and cites technical procedures existing outside of regulation. The

technical procedures result in the translation of the narrative

statement into quantitative measures; including description of how

biological assessment data is collected and analyzed, and how the

biological criteria are developed.

\--and/or\--

\(2\) A narrative statement as above plus the adoption of the

technical procedures or the actual numeric biological criteria in State

or Tribal water quality standards.

These two options for adopting quantitatively-based biological

criteria are based on existing State models such as Maine, North

Carolina and Ohio (EPA 230-R-96-007). North Carolina has adopted a

narrative biological criteria for its aquatic life use classification

and cites in the water quality standard regulation the standardized

methods for data collection and analysis. Maine and Ohio have developed

more refined classifications of their aquatic life uses and developed

biological criteria for each specific use. Both States cite technical

manuals specifying standardized methods. Ohio has adopted its numeric

biological criteria directly into its standards regulation. As

mentioned earlier, the Maine Department of Environmental Protection is

currently embarking on a rule making process to adopt its existing

standardized field methods, statistical analysis protocols and numeric

classification criterion (numeric biological criteria) into its water

quality regulation. Similar to Ohio, these rules will codify the

technical procedures for determining attainment of aquatic life use

classification. EPA describes these various States\' work for

consideration as possible models of biological criteria that would

result in the consistent translation of narrative biological criteria

into numeric criteria (e.g. quantitatively-based biological criteria).

A Regulatory Requirement for Biological Criteria

EPA is considering whether it should explicitly require States and

Tribes to adopt biological criteria in either the narrative or numeric

form, and, if not, whether an alternative approach to encouraging the

use of biological criteria is appropriate. Some States and Tribes have

already allocated resources to biological criteria development because

a regulatory requirement is anticipated at some time in the future.

Others have been unwilling to commit resources to development of

biological criteria before specifically required to do so. Concerns

have also been raised about yet another regulatory requirement to be

imposed over existing requirements that are still not fully

implemented\--adding new layers of requirements in a piecemeal fashion

without adequate resources. EPA is sensitive to the concern that

\[\[Page 36772\]\]

generating the data and developing the analytical capacity to

incorporate biological criteria into water quality standards may

present a significant resource challenge to some States and Tribes.

Advocates for a requirement for States and authorized Tribes to

adopt biological criteria argue that States and Tribes will not

implement biological criteria in a timely manner, if at all, without an

explicit Federal regulatory requirement. The viewpoint has been

expressed that States and authorized Tribes will not adequately

increase program emphasis or resources if biological criteria are not

required and, as a consequence, biological criteria will be relegated

to a lesser role then chemical water quality criteria or whole effluent

toxicity. Some States have either direct (i.e. executive orders,

legislative mandates) or indirect limitations on adopting new

regulations and policies that are more stringent than that required by

Federal legislation. Adopting biological criteria may be seen in some

States and Tribes as exceeding minimum Federal requirements. Concern

has been expressed that without biological criteria as a fundamental

component of a State or Tribal water quality standards program,

transition of water quality standards programs to a more integrated

ecosystem approach with an emphasis on watersheds will not succeed.

Adoption of Narrative Biological Criteria

As an alternative to requiring adoption of numeric biological

criteria, EPA could require States and Tribes to adopt a narrative

biological criteria. The narrative biological criteria could be a

statement of intent adopted in a State\'s or Tribe\'s water quality

standards to formally consider the fate and status of aquatic

biological communities and to establish the framework for the

consistent and quantitative translation of a State\'s or Tribe\'s

designated aquatic life uses and development of numeric biological

criteria. EPA has published a document on procedures for initiating

narrative biological criteria (EPA-822-B-92-002). An example of a

narrative biological criteria based upon that publication follows:

The State will preserve, protect, and restore the water

resources in their most natural condition deemed attainable. The

condition of these water bodies shall be determined from the

measures of physical, chemical, and biological characteristics of

each surface water body type, according to its designated use. As a

component of these measurements, the biological quality of any given

water system shall be assessed by comparison to a reference

condition(s) based upon similar regional hydrologic and watershed

characteristics (reference standardized methods and operating

protocols).

Where attainable, such reference conditions or reaches of water

courses shall be those observed to support the variety and abundance

of aquatic life in the region as is expected to be or has been

historically found in natural settings essentially undisturbed or

minimally disturbed by human impacts, development or discharges.

This condition shall be determined by consistent sampling and

reliable measures of selected indicated communities of flora and/or

fauna as established by \[cite appropriate State agency or agencies\]

and may be used in conjunction with acceptable chemical, physical,

and microbial water quality measurements and records judged to be

appropriate to this purpose.

Regulations and other management efforts relative to these

criteria shall be consistent with the objective of preserving,

protecting and restoring the most natural communities of fish,

shellfish, and wildlife attainable in these waters; and shall

protect against degradation of the highest existing or subsequently

attained uses or biological conditions pursuant to State

antidegradation requirement.

EPA is considering what could constitute approvable narrative

biological criteria and the feasibility of EPA promulgating narrative

biological criteria where a State or Tribe fails to adopt such

criteria.

Time Frame for Adoption of Biological Criteria in State and Tribal

Water Quality Standards

In 1991 EPA issued a policy that established as a long-term Agency

goal the development and adoption of biological criteria in State and

Tribal water quality programs (Transmittal of Final Policy on

Biological Assessments and Criteria, memorandum from Tudor Davies,

Director of the EPA Office of Science and Technology, to Regional Water

Management Division Directors, June, 1991). EPA has identified as a

program priority during the FY1997-1999 Water Quality Standards

Triennium that States and Tribes initiate and continue to expand

development of scientifically defensible biological-based

classification systems (FY 1997-1999 Water Quality Standards

Priorities, memorandum from Tudor Davies, Director of the EPA Office of

Science and Technology, July 22, 1996). Based on State experiences,

development of biological criteria can range between five to ten years,

depending on several factors such as available resources, existing

State expertise, existing data bases and geographic variability. If EPA

were to require or recommend that States and Tribes adopt biological

criteria, EPA would need to determine appropriate time frames for

adoption and implementation of these criteria. EPA is considering

whether the following are reasonable and appropriate time frames for

adoption of biological criteria in State and Tribal water quality

programs:

1\. narrative biological criteria for streams and an implementation

plan for development of quantitatively-based biological criteria for

streams in the 2000-2003 Water Quality Standards Triennium.

2\. narrative biological criteria and an implementation plan for

development of quantitatively-based biological criteria for other

applicable water body types (e.g. lakes and reservoirs, estuaries and

near coastal waters, large rivers and wetlands) within ten years

following EPA publication of technical guidance.

Linkage of Biological Criteria to Stressor-Identification

One of the potential benefits of developing a biological criteria

program is the increased ability to assess water quality impairment due

to nonpoint source pollution, broadening the scope of most water

quality-based programs beyond regulation of effluent discharges.

However, many currently regulated point source dischargers are

skeptical that greater focus on nonpoint source would actually occur,

particularly considering the time and resource constraints on most

State and Tribal programs. Industry and municipalities are concerned

that biological criteria bring an additional layer of regulatory and

associated costs and that they may be an easy target for additional

requirements whether their discharge is the source of impairment or

not. EPA recognizes that the role biological assessments and criteria

will play to help identify specific stressors or sources of use

impairment will need to be carefully defined and is interested in

practical, effective approaches to evaluate potential stressors and

sources of impairment when a water body fails biological criteria.

Request for Comment on Biological Criteria, Assessment and

Implementation

EPA is soliciting comment on the following questions:

1\. Should EPA amend the regulation to explicitly require States and

Tribes to adopt biological criteria or are there alternative approaches

that EPA should consider? Should EPA seek to ensure that biological

criteria will be developed and implemented in all State and Tribal

water quality programs?

2\. If EPA were to explicitly require States and Tribes to adopt

biological

\[\[Page 36773\]\]

criteria, should it require a narrative only, or a combination of both

narrative and numeric criteria as described in the draft implementation

guidance (e.g quantitatively-based biological criteria)? What should

EPA promulgate if a State or Tribe fails to adopt biological criteria

in its water quality standards?

3\. If EPA were to explicitly require biological criteria, what is a

reasonable time frame for State or Tribal adoption?

4\. What are practical, effective approaches to identify and

evaluate potential stressors and sources of impairment when a water

body fails biological criteria?

5\. In what ways can biological criteria and biological assessments

be used to effectively manage known stressors or sources of impairment,

including urban and rural runoff?

12\. Wildlife Criteria

Wildlife criteria are designed to protect mammals and birds from

adverse impacts from pollutants due to consumption of food or water

from a water body. A wildlife criteria methodology applicable to the

Great Lakes Basin and a few wildlife criteria were published as part of

the Great Lakes Guidance. EPA does not have an active wildlife criteria

guidance program at this time but it is a potential emerging criteria

program. The wildlife criteria that EPA promulgated in the Great Lakes

Guidance are for the following four chemicals: DDT (and metabolites),

mercury, PCBs, and dioxin (2,3,7,8-TCDD).

Request for Comment on Wildlife Criteria

EPA requests comment on the following question:

1\. Does the regulation need to be clarified to specifically address

the development of wildlife criteria guidance for the protection of

aquatic dependent wildlife?

13\. Physical Criteria

Physical criteria is a concept that takes into account the physical

attributes of the aquatic environment, such as quality of habitat and

hydrologic balance. Commenters on the draft ANPRM identified physical

habitat and hydrologic balance criteria as additional important forms

of criteria that should be discussed in the ANPRM. EPA agrees that

physical habitat parameters, including flow, are important and often

overlooked parameters that influence and at some sites control whether

or not an aquatic life use is or will be attained. For example,

research referenced by Schueler (see Schueler, T. The Importance of

Imperviousness. Watershed Protection Techniques, Fall 1994) suggests

that in many small urban streams substantial loadings from municipal

separate storm sewer systems are severely degrading the aquatic

habitat. The authors suggest that the primary cause of this habitat

impairment is the high volume and velocity of the storm water flows

into this type of stream. The high flows exceed the peaks in the

natural flow regime of these streams and as a result stream bank

erosion, turbidity and siltation occur and the local habitat is

degraded. Further habitat destruction in larger downstream receiving

waters often results from the physical deterioration of the upstream

urban systems. For example, some recent studies have shown that in some

lakes the biggest source of silt and sediment deposition into the lake

is actually from the eroded material that comes directly out of the

stream bed and stream banks that are scoured out during elevated wet

weather peak discharges and extended hydrographs. This can lead to

eutrophication, increased turbidity, decreased light penetration,

submerged aquatic vegetation (SAV) loss, spawning bed smothering, and

shellfish habitat damage.

Studies of this phenomenon suggest that until these man-made flow

regimes are better managed and the resulting stresses to physical

habitat corrected, no amount of control of pollutants is likely to

restore the aquatic ecosystem to a level more closely resembling a

natural state.

The character of natural waters is obviously affected by wet

weather events. Flowing waters, especially, can change dramatically

with the seasons and in response to specific precipitation events.

Seasonal and event driven changes in flows, sediment loads,

temperature, etc. are common and natural processes which are integral

to the maintenance of natural waters and their aquatic communities.

Human-caused changes to the landscape, however, have altered these

natural processes, and for many waters, the altered flows and the

contamination now associated with wet weather discharges (discharges

that occur in whole or in part as the result of wet weather events)

present significant environmental problems. Although these problems are

generally well recognized, they have been difficult to address

effectively precisely because of their magnitude and variable nature.

The CWA\'s objectives include the protection and restoration of the

physical integrity of our nation\'s waters. Scientific experts agree

that overall physical habitat loss is the single biggest factor in the

loss of aquatic species. Physical habitat damage and loss to the

nation\'s waters includes: (1) Wetlands losses; (2) the denuding of

stream banks through unwise forestry, farming, mining, and

urbanization; (3) the embedding of stream bottoms with fine-grained

silt from poorly designed and managed farm and construction sites; (4)

the damming of river systems; (5) the channelization and/or concrete

lining of rivers and streams; (6) the obliteration of ephemeral and

first-order streams and springs during urbanization and; (7) the

widening and deepening of stream channels due to high-velocity urban

storm flows.

All seven of these phenomena are common forms of aquatic habitat

damage and loss, and yet there is little national guidance to address

the physical parameters that contribute to these impacts. In addition,

EPA does not have a clear picture of how often physical habitat

parameters, including flow are used by States and Tribes to assess,

manage, and/or regulate activities that damage habitat. Some commenters

on the draft asserted that water quality criteria guidance is needed to

address these forms of habitat loss, to create threshold values to

protect designated uses and to provide measuring tools for monitoring

watershed and water body health. EPA agrees that further investigation

of the role of physical habitat parameters, including hydrologic

balance, in water quality standards programs is necessary. EPA is

considering the relative importance of such criteria guidance as

compared to other forms of criteria guidance such as ambient water

quality criteria, sediment criteria and biological criteria; and on the

likelihood that States and Tribes would develop and implement such

criteria if technical guidance and supporting policy were available.

EPA is also interested in identifying examples of where such criteria

guidance has already been used as the basis for assessing, managing and

protecting water quality.

With respect to hydrologic balance, EPA discusses the issue in the

antidegradation section of this ANPRM. Some commenters on the draft

ANPRM suggested that maintaining hydrologic balance in surface waters,

though important in the context of antidegradation, is also important

for other aspects of water quality standards. These commenters

suggested that hydrologic balance should be part of basic water quality

criteria guidance for watershed and water body assessment and for long-

term urban storm water abatement and prevention plans under

\[\[Page 36774\]\]

the storm water NPDES program, as well as for the traditional NPDES

program.

EPA is further interested in issues associated with hydrologic

imbalances created by various industries and land operations, and the

options for researching and creating a set of hydrologic balance

criteria guidance. These could include, for instance, regional minimum

stream flow criteria on a seasonal or average monthly basis, a

groundwater-recharge criterion meant to maintain adequate stream base

flow, and a peak-flood and bank full discharge prevention criterion,

perhaps based on hydrologic regions of the country.

Request for Comment on Physical Criteria

EPA seeks comment on the following questions:

1\. Would it be useful to explicitly identify physical criteria such

as habitat and hydrologic balance in 40 CFR 131 as a valid form of

criteria that States and Tribes can adopt in their water quality

standards?

2\. Would EPA technical guidance on physical criteria be useful to

States and Tribes? Is it necessary?

3\. What are some examples of physical criteria that are being used

today and what are they being used for?

4\. What should be the principal uses for physical criteria? Would

these help address pulsed or intermittent impacts, such as those from

urban and rural runoff?

14\. Human Health

Human health water quality criteria are scientifically derived

values developed by States, Tribes, or EPA to protect human health from

the deleterious effects of carcinogens and noncarcinogenic toxicants.

Human health criteria take into account the health effects from the

consumption of aquatic organisms and drinking water. Human health

criteria are based on the potential of carcinogens and noncarcinogenic

toxicants to cause adverse impacts to human health. When adopting

criteria to protect human health, a State or Tribe may use EPA\'s

Section 304(a) criteria documents or other information on factors to

derive human health criteria. However, if a State or Tribe decides to

adopt criteria less stringent than recommended by EPA, the State or

Tribe must provide documentation which supports that the approach is

based on sound scientific rationale.

Changes to the Human Health Criteria Methodology are anticipated

for proposal in the Federal Register in 1998. These changes to the 1980

ambient water quality criteria (AWQC) derivation guidelines (45 FR

79347\) are intended to reflect the many significant scientific advances

that have occurred during the past 17 years in such key areas as cancer

and noncancer risk assessments, exposure assessments and

bioaccumulation. Comments on any of the key area issues, as well as

implementation issues, are welcome and should be made during the public

comment period following the anticipated 1998 proposal.

The following discussion focuses on three key policy-related

issues, including: choice of risk levels; fish consumption assumptions

and environmental justice, and the use of maximum contaminant levels.

a\. Risk Levels. Criteria for specific pollutants for the protection

of human health rely in part on risk levels (incidence of cancer).

Numeric criteria for carcinogens are based on three inter-related

assumptions: exposure, cancer potency, and risk level. Exposure

considerations are based on a wide range of factors, including an

estimate of the rate of fish and drinking water consumption, an

estimate of the body weight of an exposed individual, and an estimate

of the rate of a chemical\'s relative tendency to bioaccumulate in fish

tissue as compared to the surrounding water. Cancer potency factors

(q1\*) provide a measure of a chemical\'s potential to cause cancer, and

are typically derived from studies on laboratory animals. The risk

level represents an incremental increase in cancer incidences resulting

from exposure to the chemical.

EPA guidance sets forth a range of criteria values that result in

calculated risk levels of 10\<SUP\>-5\</SUP\>, 10\<SUP\>-6\</SUP\>, and

10\<SUP\>-7\</SUP\> for informational purposes. Most States and Tribes

select either a 10\<SUP\>-5\</SUP\> or 10\<SUP\>-6\</SUP\> risk level as
an

appropriate value, i.e., one additional cancer incidence per one

hundred thousand or one million exposed individuals, respectively. This

level seems to represent some general scientific and public consensus

that the cancer risks are acceptably small or insignificant. States and

Tribes, however, are not limited to selecting among the risk levels

published in the CWA section 304(a) guidance documents.

If exposure assumptions are changed, while the assumed risk level

remains the same, the criterion will change accordingly. The risk to

people who intake more than the default exposure assumptions increases

with the degree of change in the intake rates. For example, if the

State or Tribe chooses to protect at a risk level of 10\<SUP\>-5\</SUP\>

and assumes a fish consumption rate of 6.5 gm/day, but some individuals

within the State or Tribe actually eat 65 gm/day of fish, the criterion

actually protects those individuals at a risk level of 1 x

10\<SUP\>-4\</SUP\> (one additional cancer case per 10,000 people). The

risk level can change based on the relative change in each parameter.

When adopting these standards, States and Tribes are strongly

encouraged to provide documentation that the assumptions made in

establishing the criteria are reasonable and adequately protect the

population, including highly exposed subpopulations at the risk level

asserted in the States\' and Tribes\' standards. EPA strongly encourages

States and Tribes to highlight these provisions of their standards

during the public participation process.

EPA\'s current criteria documents indicate the risk level within a

range of 10\<SUP\>-5\</SUP\> to 10\<SUP\>-7\</SUP\> for the general
population.

The policy has been to allow States and Tribes to select appropriate

risk levels and is consistent with the framework of the CWA that

recognizes and supports State and Tribal primacy in making risk

management decisions to protect its population provided that the goals

of the Act are met. EPA\'s approval of different cancer risk levels to

protect human health in different States or Tribes is subject to

debate. Many have questioned States\' and Tribes\' selection and EPA\'s

approval of various risk levels to protect human health. Some assert

that EPA should require all States and Tribes to adopt a single risk

level. Others believe EPA should require States and Tribes to develop

data on the different exposure assumptions that may be present within

the State or Tribe.

With regard to subpopulations that may consume higher amounts of

fish than is assumed for the general population, EPA\'s Great Lakes

Guidance stated that a risk level of 10\<SUP\>-4\</SUP\> for such

subpopulations in the Great Lakes basin can be protective.

In a draft proposal of the water quality criteria methodology

revisions, EPA is considering proposing that risk levels in the range

of 10\<SUP\>-4\</SUP\> to 10\<SUP\>-6\</SUP\> be adopted in deriving
criteria.

However, the proposed revisions also note that care must be taken in

situations where the AWQC includes fish intake levels based on the

general population to ensure that the risk to more highly exposed

subgroups (subsistence, minority) does not exceed the
10\<SUP\>-4\</SUP\>

risk level. Furthermore, EPA is considering proposing the

10\<SUP\>-6\</SUP\> risk level as the level that ensures protection for
all

exposed population groups. As stated before, all comments regarding

methodology, including risk levels,

\[\[Page 36775\]\]

should be made during the public comment period following the

anticipated 1998 Human Health Criteria Methodology proposal.

EPA intends to foster consistent approaches between Agency program

offices, including its approach to determining allowable risk levels.

The Food Quality Protection Act of 1996 (FQPA) amended the Federal

Food, Drug and Cosmetic Act (FFDCA) to prohibit EPA from issuing

tolerances for pesticide residues in or on food unless the Agency

determined that there is a \`\`reasonable certainty\'\' that the
residues

will result in \`\`no harm.\'\' Tolerances are allowable levels of

chemicals in food; food containing residues in excess of a tolerance

may not be sold in commerce. The legislative history of FQPA indicated

Congressional support for EPA\'s view that reasonable certainty of no

harm would generally be met when a non-threshold risk is below a

10\<SUP\>-6\</SUP\> level. For threshold risks, the legislative history

contained general support for a margin of safety of 100, except that

the Statute required the Agency to add an additional 10-fold margin of

safety to protect infants and children, unless the Agency concluded on

the basis of reliable data that a different margin would be safe for

infants and children. In determining whether dietary exposures are

safe, the FQPA also directs EPA to consider non-occupational exposures

to chemicals used as pesticides, and to aggregate risks from chemicals

that share a common mechanism of toxicity. EPA\'s Office of Pesticide

Programs is in the process of developing new policies in response to

the FQPA. EPA\'s Office of Water will consider these policies when they

are completed.

b\. Fish Consumption Assumptions. EPA\'s recommended human health

criteria under CWA section 304(a) guidance are currently derived with a

fish consumption rate of 6.5 grams per day (roughly one quarter ounce

of fish and shellfish). This value represents an average based on

market survey data gathered in 1973-74, and reflects a national average

for all consumers and nonconsumers of fish and shellfish from estuarine

and fresh waters. Again, EPA intends to propose revisions to the human

health methodology for deriving ambient water quality criteria,

including revisions of the fish consumption rate. Some assumptions

regarding fish consumption and criteria policy are also discussed in FR

Vol. 61, No. 239, 65183 (December 11, 1996).

EPA recognizes that, while important, the national fish consumption

estimate is one of many different parameters used to set ambient water

quality criteria to protect human health and that the interactions of

these parameters adds substantial complexity to the methodology.

However, because this component is easily understood, it receives the

most attention from the general public. Overall, EPA considers its

human health criteria methodologies to be conservative and protective

of human health.

EPA also recognizes that there are subpopulations that consume

greater quantities of fish and has considered this as part of the human

health methodology for developing water quality criteria. State and

Tribal human health criteria are often based on a risk level of

10\<SUP\>-5\</SUP\> or 10\<SUP\>-6\</SUP\> to protect people inclined to

consume higher quantities than the average. In addition, with

regulatory actions for carcinogens, individuals consuming even 20 times

the 6.5 gram amount would still be protected at the 10\<SUP\>-4\</SUP\>

risk level. (EPA is not proposing a national risk level of

10\<SUP\>-4\</SUP\> here, rather EPA is acknowledging that the level of

risk is relative to the consumption of fish (i.e., it is greater for

individuals consuming more fish than the national average).

A similar rationale for the protectiveness of a criterion may not

apply to non-carcinogenic pollutants (i.e., RfD-based chemicals), where

significantly higher fish consumption rates may (when combined with

other exposure sources) result in exposures significantly exceeding the

RfD. Although there are safety factors associated with an RfD, they are

related to uncertainties associated with the toxicological evaluation,

not with the sources and levels of exposure. Therefore, significantly

higher intakes may require more stringent criteria to protect human

health.

EPA is seeking ways to implement Executive Order 12898 (February

16, 1994, 59 FR 7629) regarding environmental justice to ensure that

water quality criteria are developed taking into account populations

such as Native Americans and other minorities, as well as other

subsistence fishers. This would include working with the scientific

community and the public to improve EPA\'s health assessments and risk

assessments and incorporate relevant issues into its policies and

guidance. This also includes mechanisms for public participation (e.g.,

meetings) for the purposes of fact-finding, receiving comments, and

conducting inquiries concerning environmental justice.

Relevant to water quality standards, EPA recognizes the need to

address issues regarding different fish consumption patterns among

subsistence, minority populations. EPA acknowledges that these groups

may consume a greater quantity of fish than the national average. In

addition, these groups have asserted that States and Tribes should be

required to take a more aggressive role in protecting them.

Guidance for Assessing Chemical Contaminated Data for Use in Fish

Advisories (Vol. 1-IV, USEPA, 1993 and 1994) notes that fish and

shellfish consumption rates vary greatly for sections of the U.S.

population (e.g., by gender, race, age, cultural and recreational

activity, and income levels). Given the wide variations in consumption

patterns, it would not seem to be possible for States and Tribes to

provide the same level of protection from contaminated fish for all

consumers. EPA believes criteria should ensure adequate protection of

all significant populations and subpopulations from reasonable risks.

States and Tribes are encouraged to consider local surveys when

selecting fish consumption rates to protect their populations since the

national average value may not be indicative of local consumption

habits. In its Water Quality Guidance for the Great Lakes System (60 FR

15366, March 23, 1995), EPA included a Great Lakes-specific fish

consumption rate of 15 grams per day. This rate was based on several

fish consumption surveys from the Great Lakes (see 60 FR 15366 at

15374, March 23, 1995.) EPA has also published for external peer review

\`\`Draft Guidance for Conducting Fish and Wildlife Consumption

Surveys.\'\' (U.S. EPA 1997).

States and Tribes could be encouraged to modify criteria on a site-

specific basis to provide additional protection appropriate for highly

exposed subpopulations. That is, where high-end consumers would not be

adequately protected by criteria derived using the default fish intake

assumption, the State or Tribe may modify this assumption to provide

appropriate additional protection. Again, such a recommendation was

made in the Great Lakes Guidance. This preference will also be stated

in the proposed revisions to the human health methodology for deriving

ambient water quality criteria.

c\. Maximum Contaminant Levels. Under the Safe Drinking Water Act

(SDWA), EPA develops chemical-specific numeric values for use in

protecting public drinking water supplies. They are maximum contaminant

level goals (MCLGs) and maximum contaminant levels (MCLs). A MCLG is a

non-enforceable concentration of a drinking water contaminant that is

protective of

\[\[Page 36776\]\]

adverse human health effects and allows an adequate margin of safety. A

MCL is the maximum permissible level of a contaminant in water which is

delivered to any user of a public water system. MCLGs are based solely

on human health considerations (i.e., an identified adverse effect to

human health, combined with an exposure intake estimate). In contrast,

MCLs are to be as close to the MCLG as feasible, taking into

consideration the availability and the cost of treatment technologies

as well as the availability of analytical methodologies. When these two

additional factors beyond health (treatment cost and analytical

factors) are considered, the MCL for some chemicals is a higher (i.e.,

less stringent) value than the MCLG. However, there are also many

chemicals for which the MCL is equal to the MCLG. This is particularly

true for noncarcinogens. Over 80% of all current MCLs for

noncarcinogens are identical to the corresponding MCLG for that

substance. For carcinogens, MCLs are always higher than MCLGs because

MCLGs for carcinogens are routinely set to zero.

Some States and Tribes utilize MCLs and MCLGs, as criteria to

protect human health under the CWA. For some chemicals, the MCL or MCLG

is more stringent than CWA section 304(a) human health criteria. In

other cases, CWA criteria are more stringent than the MCL or MCLG.

These differences come about for three basic reasons. First, as noted

above, the 304(a) criteria under the CWA and MCLGs under the SDWA are

strictly health-based values that do not account for treatment costs or

analytical limitations. The MCL, however, does take into account

treatment costs and analytical limitations. Second, the methodologies

used to calculate the 304(a) criterion and the MCLG\--both health-based

values\--for the same chemical often differ. Third, the MCLG and the

304(a) criterion sometimes have been calculated at different times,

often years apart, using the current risk and exposure information at

the time. Where different information on risk and exposure was used,

differences in the numerical values can be expected.

It is important to consider some of the methodological differences

between the derivation of 304(a) criteria and MCLs and MCLGs. Although

the methods under SDWA and CWA both use the same reference dose (RfD)

or cancer potency slope, and both methods assume a 70 kg adult and

consumption of 2 liters of water per day, there are several important

differences. One difference is that MCLGs for chemicals that are known

or likely carcinogens are usually set equal to zero, while CWA section

304(a) criteria for carcinogens are based on an incremental cancer risk

level and are never set equal to zero. For chemicals with limited

evidence of carcinogenicity, the MCLG is usually based on the

chemical\'s reference dose (RfD) for noncancer effects with the

application of an additional uncertainty factor of 1 to 10 to account

for its possible carcinogenicity. In contrast, the 1980 CWA section

304(a) criteria guidelines do not differentiate among carcinogens with

respect to the weight of evidence grouping; all were derived based on

lifetime carcinogenic risk levels.

Another important difference between the two methodologies is that

a single determined risk value (single reference dose or single cancer

risk value within the 10\<SUP\>-4\</SUP\> to 10\<SUP\>-6\</SUP\> range)
is used

in setting an MCLG, while CWA section 304(a) criteria have been derived

for each of the three incremental risk levels spanning
10\<SUP\>-5\</SUP\>

to 10\<SUP\>-7\</SUP\>, with the decision on which value to adopt left
to

the State or Tribe.

Another important methodological difference is in the approach to

accounting for exposure sources. MCLGs for RfD-based chemicals

developed under the SDWA follow a relative source contribution (RSC)

approach in which the percentage of exposure that is attributed to

drinking water is determined relative to the total exposure from all

sources (e.g., drinking water, food, air). The rationale for this

approach is to ensure that an individual\'s total exposure to a chemical

does not exceed the RfD. To develop CWA human health criteria for

noncarcinogens, the 1980 CWA National Guidelines recommended taking

non-fish dietary sources and inhalation into account. However, data on

these other sources were generally not available. Therefore, it was

typically assumed that an individual\'s total exposure to a chemical

came solely from drinking water from the water body and consumption of

fish and shellfish living in the water body. Also, CWA criteria are

based on a prediction of exposure from fish and shellfish using a

bioconcentration factor (BCF) to estimate the bioconcentration of the

individual chemical, and a fish/shellfish consumption rate. To date,

under the current MCLG methodology, BCFs have not been used in the

exposure estimates and fish/shellfish consumption rates have been only

marginally accounted for (e.g., via general FDA dietary estimate or

conservative default assumption).

Because of the differences in the approach to exposure and the

basis of toxicity values, the health-based drinking water goal (MCLG)

is sometimes more stringent than the CWA human health criterion (304(a)

criterion). However, the opposite is sometimes true. An example of the

former is 1,4-dichlorobenzene, for which both the MCL and MCLG are 75

ug/L and the 304(a) criterion (for protection of human health from the

exposures of drinking water and consuming contaminated fish) is 400 ug/

L. In this case, the MCLG was developed based on an assumption that 20%

of the total exposure is from drinking water (the RSC factor applied to

this noncarcinogen), whereas the CWA criterion effectively assumes that

non-water exposure is negligible. Additional sources of difference

between the two values are: (1) the BCF/BAF for 1,4-dichlorobenzene is

low and thus does not make the 304(a) value significantly lower; (2)

the MCLG was derived from an RfD of 0.1 mg/kg/day, while the 304(a)

criterion utilized an Acceptable Daily Intake (ADI, now replaced by the

use of RfDs) of 0.013 mg/kg/day; and, (3) the MCLG included a safety

factor of 10,000, whereas the water quality criterion included a safety

factor of only 1,000.

In contrast, for noncarcinogens where the BCF/BAF is high, the CWA

criteria may be roughly equivalent or more stringent than the health-

based drinking water levels because of the considerable exposure via

fish/shellfish consumption that is assumed in deriving the CWA

criteria. As with the previous example, the difference may be

compounded if the toxicological values have a different basis. An

example is endrin, for which the MCL and MCLG are 2 ug/L and the CWA

section 304(a) human health criterion (again, for protection from the

exposures of drinking water and consuming contaminated fish) is 0.76

ug/L. In this case, the drinking water level is, again, developed based

on the RSC assumption of 20%, whereas the CWA criterion assumes that

non-water exposure is negligible. However, the BCF/BAF for endrin is

quite high (3,970) and drives the 304(a) value significantly lower.

Furthermore, the MCLG was derived from an RfD of 3.0 x

10\<SUP\>-4\</SUP\> mg/kg/day, while the CWA criterion utilized an ADI
of

1.0 x 10\<SUP\>-3\</SUP\> mg/kg/day. With endrin, both the MCLG and the

water quality criterion included a safety factor of 100.

Of course as noted above, the MCL takes into account the cost or

availability of treatment technology or analytical methods, and may be

much less stringent than the CWA human health criterion, regardless of

the

\[\[Page 36777\]\]

exposure assumptions or toxicological basis (e.g., 1,1,2-

trichloroethane).

Because of the differing methods used to implement the SDWA and the

CWA, EPA has recommended that, where consideration of available

treatment technology, costs, or availability of analytical

methodologies has resulted in MCLs that are less protective than MCLGs

or CWA section 304(a) criteria, States and Tribes should consider using

MCLGs and/or health-based CWA section 304(a) criteria to protect

surface waters that are designated for water supply use under the

State\'s or Tribe\'s water quality standards. Furthermore, when adopting

water quality criteria to protect a surface water designated for

drinking water supply use, States and Tribes should carefully consider

what value (e.g., the MCLG or the 304(a) value) provides a defensible

estimate of the water quality level necessary to fully protect the use,

and whether relevant exposure routes have been adequately considered in

the derivation of each value.

EPA stated its policy on the use of Section 304(a) human health

criteria versus MCLs in 45 FR 79318, November 28, 1980. Additionally, a

memorandum from R. Hanmer to the EPA Regional Water Management Division

Directors dated December 12, 1988, provided detailed guidance with

regard to this policy. Specifically, for the protection of public water

supplies, EPA encouraged the use of MCLs. When fish ingestion is

considered an important activity, EPA recommended the use of 304(a)

criteria to protect human health. In all cases, if a 304(a) criterion

did not exist for a chemical, an MCL was deemed a suitable level of

protection.

The forthcoming proposed human health criteria guidelines

(scheduled for publication in 1998 and cited above) are expected to

recommend a slightly different approach. Although EPA considers the use

of MCLs to protect surface waters under the CWA to be acceptable in the

absence of 304(a) criteria, EPA expects to recommend that:

\--MCLs only be used when they are numerically the same as the MCLG and

only when the sole concern is the protection of public water supply

sources (e.g., where the chemically toxic form in water is not the form

found in fish tissue and, therefore, fish ingestion exposure is not an

issue of concern);

\--where consideration of available treatment technology, costs, or

availability of analytical methodologies has resulted in MCLs that are

different than MCLG values or 304(a) criteria, States and Tribes

consider using MCLGs and/or 304(a) criteria to protect surface waters

designated for water supply use;

\--where fish consumption is an existing or potential activity, States

and Tribes ensure that their adopted human health criteria adequately

address this exposure route;

\--where fish consumption is a designated use, States and Tribes use

304(a) criteria to protect that use because fish consumption and

bioaccumulation are explicitly addressed by the 304(a) methodology;

\--where water monitored at existing drinking water intakes has

concentrations at or below MCLGs, then the water could be considered to

meet a CWA designated use as a drinking water supply and a criterion

reflecting that level could be adopted; and,

\--for carcinogens where the MCLG is equal to zero, States and Tribes

base a criteria value at the drinking water intake on an acceptable

cancer risk level (i.e., a level within the range of 10-4 to 10-6), to

protect human health. It is not intended that MCLGs of zero would be

used as the basis for State or Tribal water quality criteria.

As States and Tribes may be more stringent than EPA, States and

Tribes may adopt an MCL or MCLG as a water quality criterion that is

more stringent than EPA\'s recommended section 304(a) criterion. In

situations where a recommended 304(a) criterion is less protective than

an MCL, EPA expects to recommend in the 1998 human health criteria

methodology proposal use of the MCL instead of the recommended 304(a)

criterion because it would help to ensure adequate source water

protection and avoid costly compliance problems for downstream water

supply utilities.

EPA has considered extensively this issue of equivalency between

the drinking water component of CWA section 304(a) criteria and MCLGs

or MCLs. EPA expects to move toward similar assessment methodologies

(including its exposure and relative source contribution \[RSC\]

policies) for deriving CWA criteria and MCLGs. Consistent exposure

evaluation methodologies for deriving CWA 304(a) criteria for human

health protection and MCLGs under SDWA, would, over time, eliminate the

need to consider using MCLs for adopting State water quality standards.

In the meantime, where there are differences between the MCLG and the

304(a) criteria for human health protection, EPA expects to continue to

recommend using as the water quality criterion the value that, in the

judgement of the State or Tribe, best accounts for the relevant routes

of exposure. Of course, EPA will also approve use of the more stringent

value.

Request for Comments on Human Health Criteria

EPA seeks public comment on the following questions:

1\. Should the regulation require, or should guidance recommend,

higher intake assumptions for site-specific or regional situations when

subpopulations that are highly exposed have been identified? If so,

what should be the basis for such intake assumptions?

2\. Should the regulation be modified to clarify (beyond the

guidance being proposed in 1998) the use of MCLs and MCLGs in State

water quality standards? \[Note: Comments on the establishment of

similar assessment methodologies for deriving CWA criteria and MCLGs

should be made during the public comment period following the

anticipated 1998 Human Health Criteria Methodology proposal.\]

15\. Microbiological Criteria

Currently EPA has a criteria document titled \`\`Ambient Water

Quality Criteria for Bacteria\--1986\'\' which provides information on

microbiological indicator organisms, sampling frequencies, and risk

based criteria guidance which States and Tribes can use in establishing

State or Tribal standards, especially for recreational waters. The

indicators used are the Enterococci for fresh and salt waters (33/100mL

and 35/100mL respectively) and E. Coli for fresh waters (126/100mL). It

is recommended that sampling be performed on a weekly basis and the

acceptability criteria are based on a running average level of the

indicators on a monthly basis. The EPA Office of Research has completed

a new Enterococci method (See \`\`Membrane Filter Test Method for

Enterococci in Water,\'\' EPA-821-R-97-004, May 1997). This indicator

method allows samples to be read in 24 hours rather than the 48 hours

of the old Enterococci method.

In 1997, EPA established the Beaches Environmental Assessment

Closure and Health Program (\`\`BEACH\'\' Program) to protect the health
of

beach goers through assistance to State, Tribal, and local health

officials in designing, developing and implementing beach monitoring

and advisory programs. The BEACH Program will also survey local beach

authorities about their programs and develop an Internet website to

provide the public with information on local beach water quality

conditions,

\[\[Page 36778\]\]

beach advisories and closures, and health risks associated with

swimming in contaminated water.

While the Enterococci and E. Coli indicators and criteria guidance

are satisfactory for determining risks from acute gastrointestinal

disease they are not necessarily acceptable for determining risks from

enteric viruses nor from pathogenic enteric protozoa such as Giardia

and Crypto Sporidium since these pathogens are much more resistant

environmentally and experience different treatment effectiveness. EPA

is currently evaluating how it may develop human health criteria for

protection from these organisms.

EPA may conduct additional research to develop indicator methods

for non-enteric pathogens that cause skin, respiratory, eye, ear, and

throat infections that are not detected by the current indicator

methods. EPA also intends to examine the phenomenon of regrowth of the

current indicators on soil and vegetation in tropical areas, and if

deemed necessary add indicator development studies to replace the

current indicators in tropical recreational areas. Further studies are

proposed to examine rapid chemical indicators of fecal pollution to see

if a tiered sampling protocol can be established for recreational water

monitoring. Also, EPA plans to examine the development of improved

monitoring strategies that States, Tribes and local authorities could

use to assess the true impact of pollution during wet weather events.

Finally, EPA will examine various computer models that could be used to

predict microbial pollution from storm water events in watersheds and

at recreational areas. These models would be validated by

microbiological monitoring.

Request for Public Comment on Microbiological Criteria

EPA seeks public comment on the following questions:

1\. Where and how is it best to conduct future programs to determine

the safety of recreational waters?

2\. What communication strategies would best inform the public about

pathogen exposures?

3\. What guidance should EPA provide to States, Tribes, and local

governments on how to conduct beach monitoring activities?

16\. Nutrient Criteria

In the National Water Quality Inventory 1994 Report to Congress,

nutrients (nitrogen and phosphorous) are cited as one of the leading

causes of water quality impairment in our Nation\'s rivers, lakes and

estuaries. While nutrients are essential to the health of aquatic

ecosystems, excessive nutrient loadings can result in the growth of

aquatic weeds and algae, leading to oxygen depletion, increased fish

and macro invertebrate mortality and other water quality impairments.

In December 1995, EPA held a National Nutrient Assessment Workshop with

the goal of developing a comprehensive nutrient strategy which would

provide tools that can be used in assessing and controlling nutrients

in all types of water bodies. Major conclusions from that workshop

were: (1) a single set of national nutrient criteria is not a realistic

goal, and (2) nutrient criteria need to be set on an ecoregional or

watershed basis. EPA has since been developing a national nutrient

strategy in order to communicate the specific approach and activities

necessary to meet the goals and major conclusions of the National

Nutrient Assessment Workshop.

On February 14, 1998, the \`\`Clean Water Action Plan\'\' was announced

by the Administrator of EPA and the Secretary of Agriculture. The

\`\`Clean Water Action Plan\'\' is a blueprint for restoring and
protecting

the Nation\'s precious water resources. As part of this Action Plan, EPA

intends to identify the major sources of nitrogen and phosphorous in

our waters and to identify actions to address these sources. In

particular, EPA intends to accelerate development of nutrient criteria

guidance for waters in every geographic region in the country, so that

EPA and the States and Tribes can begin implementing a criteria system

for nitrogen and phosphorous runoff for lakes, rivers, and estuaries by

the year 2000. EPA will assist States and Tribes in adopting numeric

water quality criteria for nitrogen and phosphorous, which EPA expects

will take the form either of State- or Tribe-derived criteria where

data is available, or criteria based on EPA default ranges applicable

to their ecoregion(s). Where a State or Tribe does not adopt

appropriate nutrient standards, EPA intends to begin the process of

promulgating nutrient standards. To support meeting these expectations,

EPA anticipates the following actions described below.

First, EPA intends to publish a National Nutrient Strategy which

will present currently available tools for assessing eutrophication,

identify important implementation issues related to controlling

eutrophication, and provide the Agency\'s plan for developing water

body-type guidance on nutrient over enrichment.

This national strategy will also present EPA\'s expectations for

action on the part of States and Tribes, namely, development of numeric

nutrient criteria and standards on a regional/watershed basis. Second,

by the end of the year 2000, EPA expects to publish the water body-type

guidance documents which would serve as \`\`user manuals\'\' for
assessing

and controlling nutrient over enrichment for specific water body types:

lakes and reservoirs, rivers and streams, and estuarine and coastal

waters. These documents will include techniques for assessing the

trophic state of a water body and a methodology for developing region-

specific nutrient criteria. In each document, EPA intends to provide

regional nutrient ranges for phosphorus and nitrogen (and other

parameters), which EPA would expect States and Tribes to use in setting

nutrient criteria in the absence of any criterion that has been

developed site-specifically. EPA intends to use existing State and

Tribal projects and data, supplemented with new regional case studies

and demonstration projects that are being conducted to collect

information in data-limited areas of the country. An important

component in developing default nutrient values is determining the

appropriate scale of application (e.g., watershed, ecoregion, Northern

lakes/Southern lakes, etc.). Finally, in order to promote the use of

the water body-specific guidance, and ensure the development of

nutrient criteria on a watershed or ecoregional basis nationwide, EPA

will undertake several activities, including: (1) training in EPA

regions and States, and Tribes, through the use of Regional Technical

Assistance Centers; (2) appointing EPA Regional Nutrient Coordinators

who will oversee the development and implementation of nutrient

criteria and standards in each of the EPA Regions; and (3) offering

assistance grants which will provide financial support to States and

Tribes in their efforts to assemble existing data, including nutrient

endpoint data, and to establish nutrient criteria either by watershed

or ecoregion, where sufficient data are available.

Request for Comments on Nutrient Criteria

EPA requests comment on the following questions:

1\. Should the regulation specifically require States and Tribes to

adopt and implement numeric nutrient criteria?

2\. What capabilities do States and Tribes have right now for

developing and implementing water quality criteria for nutrients?

\[\[Page 36779\]\]

3\. What are the institutional impediments to collecting nutrient

data and developing nutrient standards, for example, staff numbers and

expertise and financial resources?

4\. Which States or Tribes are using an ecoregion or watershed

approach to develop numeric nutrient standards (EPA is aware of some

States doing this)? For those States and Tribes that do not, on what

scale do their nutrient standards apply\--statewide or by water body

type?

D. Antidegradation

1\. Background

The Federal antidegradation policy has its roots in the Water

Quality Act of 1965 (Pub. L. 89-234), which stated in its declaration

of policy, \`\`The purpose of this Act is to enhance the quality and

value of our water resources and to establish national policy for the

prevention, control, and abatement of water pollution.\'\' Policy

guidelines established by the Department of the Interior in 1966 for

use in the approval of States\' water quality standards contained

additional direction on antidegradation, stating that \`\`In no case
will

standards providing for less than existing quality be acceptable\'\' and

\`\`The water quality standards proposed by a state should provide for:
.

. . The maintenance and protection of quality and use or uses of waters

now of a high quality or of a quality suitable for present and

potential future uses.\'\' Secretary of the Interior Udall further

defined the Federal policy on antidegradation in 1968, when he said

that each State was to include a statement similar to the following in

their water quality standards:

Waters whose existing quality is better than the established

standards as of the date on which such standards become effective

will be maintained at their existing high quality. These and other

waters of a State will not be lowered in water quality unless and

until it has been affirmatively demonstrated to the State water

pollution control agency and the Department of the Interior that

such change is justifiable as a result of necessary economic or

social development and will not interfere with or become injurious

to any assigned uses made of, or presently possible in, such waters.

This will require that any industrial, public or private project or

development which would constitute a new source of pollution or an

increased source of pollution to high quality waters will be

required, as part of the initial project design, to provide the

highest and best degree of waste treatment available under existing

technology, and, since these are also Federal standards, these waste

treatment requirements will be developed cooperatively.

The Federal Water Pollution Control Act Amendments of 1972 (Pub. L.

92-500) continued to emphasize the prevention of pollution and, in

1973, EPA developed guidance for State water quality standards under

the Amendments that essentially repeated the 1968 statements of

Secretary Udall.

In 1975, EPA promulgated regulations at 40 CFR 130.17(e) that

required the States to develop an antidegradation policy and

implementation procedures. The 1975 rule contained provisions that are

very similar to those in 40 CFR 131.12, and provided protection for

existing uses, high quality waters, high quality waters that

constituted an outstanding National resource, and waters impaired by

thermal discharges. EPA issued final rules on November 8, 1983 (48 FR

51400\) that retained, with certain changes, the 1975 antidegradation

policy and incorporated it into the regulations at 40 CFR 131.12. The

changes to the 1975 antidegradation policy are discussed in the

preamble to the 1983 rulemaking (48 FR 51402-51403), but they were

generally intended to clarify the policy with no change in coverage or

effect. An exception to this was the change in the provisions

applicable to outstanding National resource waters, which eliminated

the strict \`\`no degradation\'\' requirement in favor of a limited

exception for activities that result in temporary and short-term

lowering of water quality. The 1983 regulation (40 CFR 131.12(a))

provides that a State or Tribe is to identify its method for

implementing the antidegradation policy, i.e., decision measures for

assessing activities that may impact the integrity of a water body.

The 1987 Water Quality Act Amendments to the Clean Water Act (CWA)

explicitly incorporated reference to antidegradation policies in

section 303(d)(4)(B), which requires that such antidegradation

requirements be satisfied prior to modifying certain NPDES permits to

include less stringent effluent limitations (this concept is referred

to as antibacksliding).

On March 23, 1995, EPA published the final Water Quality Guidance

for the Great Lakes System (the Great Lakes Guidance). The Great Lakes

Guidance includes an antidegradation component that is intended to work

in conjunction with the other components of the Great Lakes Guidance to

address the most pressing threats to water quality in the Great Lakes.

In order to achieve this end, the focus of the antidegradation

component is on decisions pertaining to new or increased loadings of

specified bioaccumulative chemicals of concern within the Great Lakes

basin. For other types of pollutants, States and Tribes are required to

comply with the existing regulations at 40 CFR 131.12.

In the course of establishing a framework for making decisions

regarding increased loadings of bioaccumulative chemicals of concern,

the Great Lakes Guidance touches on a number of issues. The Great Lakes

Guidance provides a procedure for identifying high quality waters on a

pollutant-by-pollutant basis. The Great Lakes Guidance also defines how

a significant lowering of water quality will be identified for purposes

of determining whether or not an antidegradation review is required.

Finally, the Great Lakes Guidance includes implementation procedures

that describe how an antidegradation review should be conducted. In all

cases, the antidegradation components of the Great Lakes Guidance are

tailored to the control of bioaccumulative chemicals of concern; other

solutions may be necessitated by environmental threats faced elsewhere

in the Nation.

EPA\'s current thinking is that on a national scale, antidegradation

is not being used as effectively as it could be and that a structured

national debate on antidegradation is key to improvement. The debate

needs to identify deficiencies in antidegradation policy and

implementation provisions and begin the process of strengthening

antidegradation as a meaningful mechanism to attain and maintain water

quality standards. EPA invites comments and suggestions on the three-

tiered approach currently in use and described below, as well as

possible other approaches to more effectively accomplish the intent of

the antidegradation requirements. As part of the \`\`Clean Water Action

Plan\'\' announced on February 14, 1998 by the Administrator of EPA and

the Secretary of Agriculture, EPA plans to develop additional guidance

on Antidegradation. The discussion below articulates current EPA

thinking in several areas of antidegradation. Elements of this current

EPA thinking will likely be incorporated into the Antidegradation

guidance EPA develops under the \`\`Clean Water Action Plan.\'\'

2\. General Description of Antidegradation

An antidegradation policy performs an essential function as part of

the of States\' and Tribes\' water quality standards. Designated uses

establish the water quality goals for the water body, water quality

criteria define the minimum conditions necessary to achieve the goals

and an antidegradation policy specifies the framework to be used in

making

\[\[Page 36780\]\]

decisions regarding changes in water quality. The intent of an

antidegradation policy is to ensure that in all cases, at a minimum,

water quality necessary to support existing uses is maintained (tier

1), that where water quality is better than the minimum level necessary

to support protection and propagation of fish, shellfish and wildlife,

and recreation in and on the water (\`\`fishable/swimmable\'\'), that
water

quality is also maintained and protected unless, through a public

process, some lowering of water quality is deemed to be necessary to

allow important economic or social development to occur (tier 2), and

to identify water bodies of exceptional recreational or ecological

significance and maintain and protect water quality in such water

bodies (tier 3). Antidegradation plays a critical role in allowing

States and Tribes to maintain and protect the finite public resource of

clean water and ensure that decisions to allow reductions in water

quality are made in a public manner and serve the public good.

The watershed approach may be a powerful tool to achieving

antidegradation goals (i.e., maintaining the chemical, physical, and

biological integrity of the Nation\'s waters). Many and varied uses are

made of the Nation\'s waters and in some cases, these uses conflict. The

ability of particular waters to accommodate all uses is limited. High

quality surface waters are an important and finite resource whose

availability affects the health, welfare, and economic well-being of

all the citizens of the United States. When operating properly, the

antidegradation policies of States and Tribes ensure that water quality

is conserved where possible and lowered only when necessary, and that

those affected by the lowering of water quality have a say in the final

decision. As a result, antidegradation policies are well-suited to

assist States, Tribes and local communities in establishing and

achieving watershed goals. Sensitive or highly valued water bodies can

be identified and protected from degradation through outstanding

national resource water (ONRW) or related designations. In other water

bodies, where water quality is better than the minimum necessary to

support fish and aquatic life and recreation, water quality should be

maintained unless there is a demonstrated need to lower water quality.

Consistent with the watershed approach and community-based

environmental management, States\' and Tribes\' antidegradation policies

and procedures can be a basis for a systematic and accessible planning

process that protects against development having negative impacts on

water quality. Additional authorities exist at the local level beyond

State, Tribal and federal authorities which may allow additional

protections to be put in place in accordance with the watershed

management plan.

The water quality standards regulation requires each State and

authorized Tribe to adopt, as part of its water quality standards, an

antidegradation policy consistent with 40 CFR 131.12 and identify

implementation methods for such a policy. This antidegradation policy

provides a multi-level approach for the protection of water quality and

applies to both point and non-point source activities. The level of

protection that is provided to a specific segment depends upon a number

of factors (e.g., a key determinant is whether existing water quality

is found to exceed levels necessary to support
\`\`fishable/swimmable\'\'

uses). Antidegradation requirements are typically triggered when an

activity is proposed that may have some effect on existing water

quality. Such activities are reviewed to determine, based on the level

of antidegradation protection afforded to the affected water body

segment, whether the proposed activity can be authorized.

\`\`Antidegradation reviews\'\' under all three tiers of antidegradation

should be documented and subjected to public review and comment (e.g.,

as part of the public review of the water quality certification, NPDES

permit, or other regulatory action).

Identifying the universe of activities that trigger antidegradation

requirements is a fundamental and often controversial issue because of

the number and variety of activities that can affect water quality.

Clearly, a wide range of activities that affect water quality may be

subject to antidegradation requirements, and States and Tribes have

considerable flexibility in applying antidegradation policies.

The federal antidegradation requirements do not create, nor were

they intended to create, State or Tribal regulatory authority over

otherwise unregulated activities. It is the position of EPA that, at a

minimum, States and authorized Tribes must apply antidegradation

requirements to activities that are \`\`regulated\'\' under State,
Tribal,

or federal law (i.e., any activity that requires a permit or a water

quality certification pursuant to State, Tribal or federal law, such as

CWA Sec. 402 NPDES permits or CWA Sec. 404 dredge and fill permits, any

activity requiring a CWA Sec. 401 certification, any activity subject

to State or Tribal nonpoint source control requirements or regulations,

and any activity which is otherwise subject to State or Tribal

regulations that specify that water quality standards are applicable).

Where a State or Tribe wishes to require antidegradation reviews for

activities that are not currently \`\`regulated\'\' under this
definition,

EPA recommends that a complete discussion of the activities requiring

an antidegradation review be included in the State or Tribal water

quality standards or other State or Tribal regulation. Although States

and authorized Tribes have discretion to apply antidegradation

requirements more broadly than minimally required, application of

antidegradation requirements to activities that are otherwise

unregulated under State, Tribal, and federal water law is not required

by the federal water quality standards regulation.

EPA\'s current thinking is that antidegradation principles can and

should be considered in connection with a number of activities even

where application of the antidegradation review requirements is not

explicitly required by the regulation. EPA is interested in identifying

ways to better implement antidegradation, especially for activities

such as urban and agricultural run-off. As part of general planning for

development that is likely to affect surface water quality, it makes

sense to consider existing ambient water quality and evaluate available

means to protect that water quality. Thus, although a State or Tribe

may not require a formal antidegradation review for a particular

activity (e.g., an unregulated nonpoint source), there may still be

value in applying the antidegradation principles in an analysis of

potential environmental impacts.

In sum, EPA\'s current thinking is that the antidegradation policy

is significantly underused as a tool to attain and maintain water

quality and plan for and channel important economic and social

development that can impact water quality. EPA believes this is

especially true for nonpoint source run-off. This ANPRM provides an

opportunity to identify and evaluate options for clarifying and

strengthening antidegradation policy and its implementation.

States and authorized Tribes often submit implementation procedures

to EPA for review as part of the water quality standards triennial

review required by section 303(c) of the Act. This enables EPA to

determine if the implementation procedures fulfill the requirements of

the antidegradation

\[\[Page 36781\]\]

policy. The antidegradation policy itself is expressly required by 40

CFR 131.20(c) to be submitted to EPA for review. EPA\'s longstanding

policy is that the implementation procedure should also be submitted to

EPA for review. Often, however, implementation procedures are not

submitted to EPA. EPA\'s current thinking is that an important change to

the regulation would be to clarify under 40 CFR section 131.20(c) that

State and Tribal antidegradation implementation procedures (in addition

to the policy) must be included in the submittal of a State\'s or

Tribe\'s water quality standards. Such a change could establish the

foundation for additional substantive changes to the regulation

concerning national norms for antidegradation implementation

procedures.

A State\'s or Tribe\'s implementation method is on occasion so

constructed as to essentially set aside the intent of the

antidegradation policy. EPA has disapproved this aspect of State

standards where the implementation procedure is inconsistent with the

policy. Revising the regulation to specify requirements addressing the

content of such implementation procedures (e.g., a core set of issues

that must be resolved), and clarifying that implementation procedures

must be included in the submittal package, may help to clarify EPA\'s

role in determining whether State or Tribal antidegradation

implementation procedures adequately uphold and implement the State\'s

or Tribe\'s antidegradation policy. In addition, specifying in the

regulation the basic elements of an implementation procedure could

serve to better establish national norms for State and tribal

antidegradation procedures. EPA is considering whether it would assist

States and Tribes if the regulation were amended to identify the basic

elements that must be included in an antidegradation implementation

method.

Guidance on developing antidegradation implementation methods is

provided through EPA\'s Regional Offices. EPA has not issued national

guidance on these implementation methods and is interested in comments

on whether national guidance on antidegradation implementation methods

is needed, and whether elements of such guidance should be referenced

or included in the Regulation.

Request for Comments on General Antidegradation Policy

EPA requests comment on the following questions:

1\. What changes or clarifications could be made to the current

tiered approach to protecting waters under antidegradation that would

streamline and enhance antidegradation implementation?

2\. Should the regulation be amended to identify the basic elements

that must be included in an antidegradation implementation method and

would such changes assist States and Tribes in understanding the

requirements and in utilizing the flexibility available?

3\. Is national guidance on antidegradation implementation methods

needed and should elements of such guidance be referenced or included

in the Regulation?

3\. 40 CFR 131.12 (a)(1) \`\`tier 1\'\'

Section 131.12 (a)(1) of the antidegradation policy contained in

the water quality standards regulation requires that existing uses and

the water quality necessary to protect them be maintained and

protected. This provision, in effect, establishes the floor of water

quality in the U.S. It also protects the environment where the existing

use of a water body happens to be better than the use designated by the

State or Tribe. An existing use as defined in 40 CFR 131.3 can be

established by demonstrating that a use has actually occurred since

November 28, 1975, or that the water quality is suitable to allow such

uses to occur, whether or not such uses are designated uses for the

water body in question. All waters of the U.S. are subject to tier 1

protection. In general, waters that are subject to only tier 1

antidegradation policies are those water bodies that do not exceed the

CWA Section 101(a)(2) goals, or do not have assimilative capacity to

receive additional quantities of a pollutant(s) without jeopardizing

the existing use. Existing uses and additional issues related to

defining them and their relationship to designated uses are further

discussed in section III(B)(3) of this document.

Antidegradation policies are generally implemented for tier 1 by a

review procedure that evaluates any discharge to determine whether it

would impair an existing use. Prior to authorizing any proposed

activity, a State or authorized Tribe shall ensure that water quality

sufficient to protect existing uses fully will be achieved. In addition

to ensuring that existing uses will be protected, the State or Tribe

should ensure that all existing uses are designated in accordance with

40 CFR 131.10(i).

a\. Tier 1 Implementation. In order to implement tier 1, a State or

Tribe must define what is meant by the term \`\`existing in-stream water

use\'\' (40 CFR 131.12(a)(1)) and must also be able to identify the
level

of water quality that is required to permit an existing use to continue

to occur. Section 131.3 defines existing uses as, \`\`those uses
actually

attained in the water body on or after November 28, 1975 \* \* \*\'\'

Traditionally, when establishing designated uses, States and Tribes

tend to define uses in terms of broad classes, such as warm water

fishery or secondary contact recreation. Inherent in each of the broad

use categories are specific uses that may be affected by a change in

water quality. For example, a warm water fishery designated use may

include the existing use of large mouth bass fishery. Many people would

be upset if the warm water fishery designated use was protected in such

a way as to allow a decline in the bass population. The central

question faced by States and Tribes in determining whether or not a

proposed action will impact existing uses is whether each specific use

within a use class must be maintained (each individual type of

species), or whether only the use class itself must be maintained

(allow changes in species composition, but maintain a fishery). State

and Tribal interpretations of this requirement vary considerably and

are often tied to the degree of precision the State or Tribe achieves

in defining designated uses.

Many States and some Tribes have addressed these questions by using

the same degree of precision for both designated and existing uses.

EPA\'s current thinking is that this is an acceptable approach as long

as the State\'s or Tribe\'s designated uses and criteria applicable to

those uses are adequate to ensure that existing uses are maintained

under the federal antidegradation provisions. It would not be

acceptable, for example, for a state to allow the loss of an existing

natural cold water community in favor of a warm water community because

both satisfy the general use designation of \`\`aquatic life.\'\' Nor
would

it be acceptable to allow shifts from existing pollution intolerant

communities to communities that tolerate degraded conditions. The

advantage of this approach is that the same criteria used to protect

the designated use can be assumed to also protect the existing use.

Under this approach, however, the protection afforded to existing uses

is limited by the degree of refinement associated with the designated

uses. States and Tribes that have more specific designated uses (i.e.,

including a number of use sub-categories) can potentially provide more

protection by addressing more subtle changes to the existing use.

States and

\[\[Page 36782\]\]

Tribes with less specific designated uses would have less precision

associated with their existing use protection scheme.

An important tier 1 implementation issue concerns how a State or

Tribe will prevent negative or harmful impacts to existing uses when

water quality criteria that have been established to protect the

designated uses are not adequate to protect the existing uses. For

example, a regulated discharge of uncontaminated sediment may result in

significant negative or harmful impacts to aquatic life habitat and

loss of aquatic life use. In such cases, where clean sediment or

siltation criteria have not been developed for the site, and where the

State or Tribe has not established clear procedures to implement

narrative criteria governing sedimentation, it may be difficult to

prohibit such loss of use, particularly where a State or Tribe has not

adopted biological criteria.

A second example arises where a proposed activity will result in

the discharge of a substance for which numeric criteria have not been

adopted by the State or Tribe, but sufficient data to derive criteria

or a numeric translation of the narrative criteria are available. Where

a range of numeric criteria can potentially be justified for the

particular substance to protect the designated and/or existing use, it

may be difficult or contentious for the State or Tribe to derive

effluent limits protective of the existing use.

A third example arises where a proposed hydrologic modification

will result in diminished flow in a water body and create the potential

for loss of existing aquatic life use either through increased

temperatures or turbidity, or loss of habitat. State and Tribal water

quality criteria generally do not describe minimum acceptable flows and

may not, by themselves, adequately protect against such loss of use. In

P.U.D. No. 1 of Jefferson County and City of Tacoma v. Washington

Department of Ecology, (114 S.Ct 1900 (1994)), the Supreme Court ruled

that State certifications under section 401 of the CWA may include

conditions to ensure compliance not only with a State\'s water quality

criteria, but also with a State\'s designated uses or antidegradation

policy. The Court concluded that a State could require, in this case, a

dam to be designed and operated in such a way as to maintain stream

flows necessary to protect the designated use of a stream. While this

specific case had to do with a dam and stream flows necessary to

protect a use, it should be noted that the opinion applies more broadly

than to just flow and that in addition to maintenance of in-stream

flows to protect water quality standards, States may also apply any

other parameter that may not be specifically identified in the State\'s

standards. EPA notes that where such implementation methods are spelled

out, as a practical matter, they may be more easily implemented. (See

related discussion in Section III.B. on uses). EPA believes that tier 1

methods or policies for addressing situations such as those described

above may need to be included in an antidegradation implementation

procedure.

Request for Comments on Antidegradation Tier 1

EPA specifically requests public comment on the following

questions:

1\. Do State and Tribal programs under the existing regulation do an

adequate job of protecting existing in-stream uses?

2\. Is a more detailed definition of \`\`existing in-stream water

uses\'\' needed in the regulation? Should it be the same as \`\`existing

uses?\'

3\. Should the regulation define what constitutes loss of an

existing in-stream water use?

4\. Should a clear approach to maintaining and protecting existing

uses that may not be adequately protected by strict application of

water quality criteria be a required element of an antidegradation

implementation procedure?

5\. Should the regulation specify under antidegradation that

protection of both existing and designated uses is required?

4\. 40 CFR 131.12 (a)(2) \`\`tier 2\'\'

\`\`Tier 2\'\' (Sec. 131.12(a)(2)) antidegradation policies are

intended to protect the waters in which water quality is better than

necessary to support propagation of fish, shellfish and wildlife, and

recreation in and on the water body. These are called high quality

waters. For such high quality waters, existing water quality must be

maintained and protected unless it is demonstrated that a lowering of

water quality is necessary to accommodate important economic or social

development. The protection of high quality waters envisioned by the

regulation encourages a systematic, public decision making process for

determining whether or not to allow limited deterioration of water

quality in high quality waters.

a\. Identification of \`\`High Quality\'\' Waters. Identifying waters

that are \`\`high quality\'\' and subject to tier 2 protection is an

important antidegradation issue. The water quality standards regulation

requires application of tier 2 requirements \`\`where the quality of the

waters exceed levels necessary to support propagation of fish,

shellfish, and wildlife and recreation in and on the water.\'\' However,

the regulation does not include specific guidelines for identifying

high quality waters. Various EPA guidance documents, including those

issued by EPA\'s Regional offices, make a variety of suggestions

concerning approaches to defining tier 2 waters. Not surprisingly,

States and Tribes have developed various ways to identify tier 2

waters.

Existing approaches for identifying high quality waters fall into

two basic categories: (1) pollutant-by-pollutant approaches, and (2)

water body-by-water body approaches. States and Tribes following the

first approach determine whether water quality is better than

applicable criteria for specific pollutants that would be affected by

the proposed activity. Thus, available assimilative capacity for any

given pollutant is always subject to tier 2 protection, regardless of

whether the criteria for other pollutants are satisfied. Such

determinations are made at the time of the antidegradation review

(i.e., as activities that may degrade water quality are proposed).

States and Tribes following the second approach weigh a variety of

factors to judge a water body segment\'s overall quality. Such

determinations may be made prior to the antidegradation review (i.e.,

the State or Tribe may assign \`\`high quality\'\' designations in the

State or Tribal standards), or during the course of the antidegradation

review. Under this water body-by-water body approach, sometimes

referred to as the \`\`designational\'\' approach, assimilative capacity

for a given pollutant may not be subject to tier 2 protection if,

overall, the segment is not deemed \`\`high quality.\'\'

There are advantages and disadvantages to each approach. EPA\'s

current thinking is that neither approach is clearly superior and that

either, when properly implemented, is acceptable. EPA has approved both

approaches in State standards. Some States and Tribes have found the

pollutant-by-pollutant approach to be easier to implement because the

need for an overall assessment considering various factors is avoided.

Also, decisions are driven strictly by water column data (i.e., rather

than judgments concerning a segment\'s overall value or quality) and

thus may be less susceptible to challenge. The pollutant-by-pollutant

approach may result in more waters receiving some degree of tier 2

protection because it would cover

\[\[Page 36783\]\]

waters that are clearly not attaining goal uses (i.e., waters which are

not supporting \`\`fishable/swimmable\'\' goal uses but that possess

assimilative capacity for one or more pollutant).

The water body-by-water body approach, on the other hand, allows

for a weighted assessment of chemical, physical, biological, and other

information (e.g., unique ecological or scenic attributes). In this

regard, the water body-by-water body approach may be better suited to

EPA\'s stated vision for the water quality standards program: refined

designated uses with tailored criteria, complete information on uses

and use attainability, and clear national norms. The water body-by-

water body approach preserves water quality even if criteria for

certain pollutants are not attained or if criteria for certain uses may

be limited, such as fish consumption. This approach also allows for the

high quality water decision to be made in advance of the

antidegradation review (and included in the water quality standards for

the segment), which may facilitate implementation. A water body-by-

water body approach also allows States and Tribes to focus limited

resources on protecting higher-value State or Tribal waters. The water

body-by-water body approach can also distinguish between high quality

waters and high water quality and preserve high quality waters on the

basis of physical and biological attributes, rather than high water

quality attributes alone. However, the flexibility of the water body-

by-water body approach is also its principal disadvantage where a State

or Tribe does not develop inclusive qualification criteria. For

example, where a State\'s or Tribe\'s implementation guidelines define a

narrow universe of waters, many deserving high quality waters may not

receive tier 2 protection. Thus water quality may actually decrease in

the waters not classified for tier 2 protection without a public review

of the development decision. Also, a potential problem can arise if the

process of identifying high quality waters becomes so complicated,

resource-intensive, and data-intensive that the primary purpose of tier

2 (i.e., seeking to maintain and protect existing quality by

identifying whether there are reasonable less-degrading or non-

degrading alternatives) is not adequately accomplished. In other words,

the limited resources available for water quality protection could be

spent on the identification process at the expense of analysis of the

necessity for degradation.

b\. Tier 2 Implementation. The current regulation provides a great

deal of flexibility to States and Tribes in implementing tier 2

requirements. Some States and Tribes devote little effort to

implementing their tier 2 requirements, some States and Tribes apply

tier 2 requirements in an inconsistent or infrequent manner, and other

States and Tribes have active programs that routinely and consistently

implement tier 2. In general, those States and Tribes that actively

implement their tier 2 requirements do so by conducting an

antidegradation review to determine whether proposed activities that

might affect water quality may be authorized. EPA\'s current sense is

that the antidegradation policy, in reality, has little effect on

decisions related to surface water quality unless the State or Tribe

adopts an implementation procedure and uses it. EPA currently reviews

all State and Tribal water quality standards at the time of adoption/

revision to ensure they establish a clear approach to implementation. A

brief discussion of a number of the major implementation issues is

presented below.

i\. Triggers for tier 2 Review. Although not discussed in 40 CFR

131.12 of the water quality standards regulation, State and on occasion

Tribal tier 2 implementation procedures often include guidelines which

are used to determine when the water quality degradation that will

result from a proposed activity is significant enough to warrant

further antidegradation review. Where the degradation is not

significant, the antidegradation review is typically terminated for

that proposed activity. The significance evaluation is usually

conducted on a pollutant-by-pollutant basis, even where a water body-

by-water body approach is used to identify high quality waters, and

significant degradation for any one pollutant triggers further review

for that pollutant.

Applying antidegradation requirements only to activities that will

result in significant degradation is a useful approach that allows

States and Tribes to focus limited resources where they may result in

the greatest environmental protection. However, there is a great deal

of variation in how States and Tribes define significant degradation.

Significance tests range from simple to complex, involve qualitative or

quantitative measures or both, and may vary depending upon the type of

pollutant (e.g., the approach may be different for highly toxic or

bioaccumulative pollutants). In some cases, States have also created

categorical exemptions from tier 2 review (e.g., they have exempted

entire categories of activities from antidegradation reviews based on a

general finding that such activities do not result in significant

degradation). States or Tribes that define a high threshold of

significance may be unduly restricting the number of proposed

activities that are subject to a full antidegradation review. Further

the approach currently used by some States may not adequately prevent

cumulative water quality degradation on a watershed scale. The current

regulation does not specify a significance threshold below which an

antidegradation review would not be required. EPA\'s current thinking is

that a clear national norm regarding this \`\`significance test\'\' is

necessary and should be developed and established in either the

regulation or national guidance.

A related issue concerns whether tier 2 should be applied to

pollutants where numeric criteria have not been adopted. For example,

where there is a proposed discharge of a pollutant to a \`\`high

quality\'\' segment, and the background concentration of the pollutant
is

at or near zero in the water body, should significant degradation be

evaluated and should it be evaluated any differently where numeric

criteria for the pollutant have not been adopted? For example, where a

State or Tribe lacks numeric criteria for nutrients such as nitrogen

and phosphorus (a common occurrence), increased discharges of these

nutrients can be expected to result in changes in plant life or species

diversity. If the State or Tribe relies entirely on a pollutant

loadings comparison to numeric criteria for the tier 2 evaluation, new

loadings of nutrients may not even be evaluated under tier 2.

EPA\'s sense is that, in practice, the current tier 2 requirements

tend to be used to protect high quality waters only where such high

quality supports fishing and swimming uses. However, limiting tier 2

protection to assimilative capacity associated with only fishing and

swimming uses means that the protection afforded by tier 2 can end up

being narrower than intended. For example, where a water has unique

ecological significance (e.g., acid bog or thermal spring) not captured

by \`\`fishable/swimmable,\'\' the State or Tribe may not believe it is

appropriate to designate the water as high quality under tier 2. In

this case, the unique ecological characteristic would warrant

protection as an existing use. The State or Tribe also has the option

of designating the water ONRW, yet, as discussed elsewhere in this

section, EPA believes that many States and Tribes are not inclined to

designate waters ONRW. The result in this example is that a water with

unique

\[\[Page 36784\]\]

ecological significance that may warrant a relatively high level of

protection, falls through the crack between tiers 1 and 2 where the

State or Tribe interprets the level of protection afforded by those

tiers too narrowly.

ii\. \`\`Necessary\'\' Lowering of Water Quality. The water quality

standards regulation requires that the water quality of high quality

waters not be lowered unless the State or Tribe determines that such

degradation is necessary to accommodate important social and economic

development. Given the variety of available engineering approaches to

pollution control and the emerging importance of pollution prevention,

the finding of necessity is among the most important and useful aspects

of an antidegradation program and potentially an extremely useful tool

in the context of watershed planning. An approach that has been

recommended by EPA is to require the proponent of the proposed activity

to develop an analysis of pollution control/pollution prevention

alternatives. In conducting its antidegradation review, the State or

Tribe then ensures that all feasible alternatives to allowing the

degradation have been adequately evaluated, and that the least

degrading reasonable alternative is implemented. Also, note that where

less-degrading alternatives are more costly than the pollution controls

associated with the proposal, the State or Tribe should determine

whether the costs of the less-degrading alternative are reasonable. EPA

believes that such an alternatives analysis approach can be an

effective tool for maintaining and protecting existing assimilative

capacity. EPA\'s current thinking is that specifying what would

constitute an acceptable alternatives analysis in the regulation, could

result in the addition of substance and rigor to the \`\`tier 2\'\'

antidegradation reviews conducted by States and Tribes.

iii\. Identification of \`\`Important\'\' Social or Economic Activities.

Another task that must be completed as part of an antidegradation

review is to evaluate whether a proposed activity that will result in

degradation is necessary to accommodate important social or economic

development in the area in which the waters are located. (40 CFR

131.12(a)(2)) The significance of determining if an activity will

provide for important social or economic benefit is that, absent

important social or economic benefit, degradation under tier 2 must not

be allowed. Factors that may be addressed in such an evaluation

include: (a) employment (i.e., increasing, maintaining, or avoiding a

reduction in employment), (b) increased production, (c) improved

community tax base, (d) housing, and (e) correction of an environmental

or public health problem. Some States or Tribes have addressed this

issue by requiring the applicant to bear the burden of demonstrating

the social and economic importance of the proposed activity. However,

approaches for evaluating social and economic importance vary widely.

EPA published Interim Economic Guidance for Water Quality Standards:

Workbook, Appendix M to the \`\`Water quality Standards
Handbook\--Second

Edition\'\' in March 1995 (EPA-823-B-95-002, March 1995). This guidance

specifically addresses the determination of social and economic

importance in the context of a tier 2 antidegradation review and should

be useful to States and Tribes in determining the relative economic

consequences of various development proposals and their relationship to

water quality standards. EPA\'s current thinking is that determining the

social and economic importance of a proposed activity is an important

public question best addressed by State, Tribal or local interests,

perhaps as part of the development of a basin plan.

iv\. Tier 2 and Identification of Waters under CWA Section 303(d).

Section 303(d) of the Clean Water Act and EPA regulations require

States to develop lists of waters that do not meet State water quality

standards, even after point sources of pollution install the minimum

required levels of pollution control technology. Section 303(d) lists

must be submitted to EPA every two years. The waters on the lists are

called water quality-limited waters and are defined in EPA regulations

as waters \`\`where it is known that water quality does not meet

applicable water quality standards, and/or is not expected to meet

applicable water quality standards, even after the application of the

technology-based effluent limitations required by section 301(b) and

306 of the \[Clean Water\] Act.\'\' 40 CFR 130.2(j). States are then

required to develop total maximum daily loads (TMDLs) for water

quality-limited waters.

EPA\'s current policy is that States include waters on section

303(d) lists if applicable water quality standards are not met or are

not expected to be met by the next list submission deadline, i.e.,

within two years (see memorandum from Robert Wayland, Director Office

of Wetlands, Oceans and Watersheds, to Water Management Division

Directors, Regions I-X, Directors Great Water Body Programs and Water

Quality Branch Chiefs, Regions I-X, Subject: National Clarifying

Guidance for 1998 State and Territory Section 303(d) Listing Decisions,

August 27, 1997). In determining whether to list waters, States should

consider all aspects of applicable water quality standards, including

narrative and numeric criteria, designated uses, and antidegradation

policies.

EPA is currently discussing with stakeholders possible changes and

clarifications to the water body listing regulations and guidance under

section 303(d) of the Act. Changes and/or clarifications could include

a statement in the regulation, or a clarification, that identifies

existing tier 2 antidegradation analyses and decisions as \`\`existing

and readily available water quality-related data and information\'\'
that

must be considered under 40 CFR 130.7(b)(5) when deciding whether to

place a water body on a section 303(d) list. Information from existing

antidegradation tier 2 reviews on assimilative capacity for particular

water bodies could be used to determine whether a water body is likely

to not meet water quality standards in the near future and thus

required to be included on the section 303(d) list. In addition, EPA

could amend the existing antidegradation regulations to direct States

and Tribes to consider the 303(d) listing status of a water body, and

the information supporting that status, when determining whether a

proposed activity that is expected to degrade water quality in that

water body can be authorized under tier 2 of the State\'s or Tribe\'s

antidegradation provisions.

v\. Achieving all cost-effective and reasonable best management

practices for nonpoint sources. This implementation issue arises from

one sentence that is included in the federal antidegradation policy at

40 CFR 131.12(a)(2):

Further, the State shall assure that there shall be achieved the

highest statutory and regulatory requirements for all new and

existing point sources and all cost-effective and reasonable best

management practices for nonpoint source control.

This sentence has been somewhat controversial over the years

because it could be interpreted to require a State or Tribe to include,

in its water quality standards, a provision requiring adoption of

authority for, as well as achievement of, best management practices

(BMPs) for nonpoint sources prior to allowing degradation of high

quality waters. EPA has interpreted 131.12(a)(2) as not requiring a

State or Tribe to establish BMP requirements for nonpoint sources where

such BMP requirements do not exist. As EPA clarified in a February 22,

1994 guidance memorandum, State and

\[\[Page 36785\]\]

Tribal antidegradation rules need only include provisions to assure

achievement of BMPs that are required under State or Tribal nonpoint

source control laws or regulations. (Memorandum from Tudor T. Davies,

Director EPA Office of Science and Technology to EPA Water Management

Division Directors, Regions I-X, Subject: Interpretation of Federal

Antidegradation Regulatory Requirement, February 22, 1994) Thus, States

and Tribes that have adopted nonpoint source controls must assure that

such controls are properly implemented before authorization is granted

to allow point source degradation of water quality.

EPA\'s current thinking is that the term \`\`all cost-effective and

reasonable best management practices for nonpoint source control\'\' in

40 CFR 131.12(a)(2) would be more effective if read more broadly. In

other words, the term could include nonpoint source best management

practices established through Federal, State, Tribal, and local

authorities and programs that address activities on the land or water

that create or exacerbate impacts to surface waters. This construction

is consistent with EPA\'s Total Maximum Daily Load (TMDL) program under

Section 303(d) of the Clean Water Act. There, EPA\'s current policy is

that in achieving pollutant load reductions from nonpoint sources, EPA

and States should work in partnership, using all available Federal,

State, and local authorities and programs. As EPA stated in an August

1997 TMDL guidance memorandum, States are expected to achieve nonpoint

source pollutant load reductions through such authorities and programs,

including non-regulatory, regulatory, or incentive-based programs. EPA

is considering applying the same test to Sec. 131.12(a)(2).

In addition, EPA\'s current thinking is that it may be time to begin

to more actively ensure implementation of this requirement: to

implement cost effective and reasonable best management practices for

nonpoint source control before allowing lowering of water quality in a

water body. One way to do this would be to specify that State and

Tribal antidegradation implementation procedures include a step under

which States and Tribes inventory their nonpoint source authorities and

programs, and, as part of each antidegradation review, include in the

record documentation on how those authorities and programs were applied

to activities in a watershed in which additional loadings subject to an

antidegradation review have been considered. Emphasizing this

requirement by specifying it as a required aspect of a State or Tribal

antidegradation implementation procedure, in EPA\'s view, would

facilitate use of antidegradation policy as a tool to ensure that

nonpoint sources are controlled where possible in accordance with water

quality standards, before any additional assimilative capacity in a

water body can be allocated to an activity. EPA is interested in

comment on this current thinking and specifically on whether it would

be helpful to revise the regulation to clarify the relationship between

nonpoint source controls and tier 2 antidegradation requirements.

In summary, numerous stakeholders have commented to EPA that

antidegradation reviews are conducted inconsistently across the country

and that EPA should attempt to improve the national consistency of such

reviews. EPA is interested in comment on the appropriate balance

between national consistency and State and Tribal flexibility in the

implementation of the tier 2 provision and on what changes may be

needed to the regulation or EPA policy or guidance to ensure that the

tier 2 provision is implemented in a nationally consistent manner that

is consistent with the intent of the antidegradation provision, and

whether a consistent approach should be the goal of States\' and
Tribes\'

watershed programs.

Request for Comments on Antidegradation Tier 2

EPA requests comment on the following questions:

1\. Does the existing requirement to apply tier 2 \`\`where the

quality of the waters exceed levels necessary to support propagation of

fish, shellfish, and wildlife and recreation in and on the water\'\'

while at the same time \`\`protecting existing uses fully\'\' need to be

clarified with respect to which waters are afforded tier 2

antidegradation protection, and if so, should the Agency clarify the

requirement with additional guidance, or with revisions to the

regulation?

2\. What factors should be considered in identifying \`\`high

quality\'\' waters? Should the decision be based strictly on chemical

water column quality (i.e., a pollutant-by-pollutant approach), or

should a segment\'s overall quality or other factors be considered

(i.e., a water body-by-water body approach)?

3\. Given EPA\'s current thinking that both approaches may be

acceptable and neither is necessarily superior, are the two approaches

compatible and could they be implemented together?

4\. Should application of tier 2 be clarified so that protection of

assimilative capacity associated with non-fishable/swimmable uses is

clearly required?

5\. What methods are currently being used by States and Tribes to

define \`\`significant degradation\'\'?

6\. How should \`\`significant degradation\'\' be defined? Is there a

need for a nationally consistent approach? Should EPA issue additional

guidance, or revise the regulation to include, for purposes of

implementing tier 2 requirements, a definition of significant

degradation? Are categorical exemptions appropriate, and if so, under

what circumstances?

7\. How should cumulative effects in a watershed be considered in

assessing the significance of the degradation that will occur as a

result of a proposed activity?

8\. How should the \`\`necessity\'\' of degradation be determined? When

should the costs of less degrading alternatives be considered

reasonable?

9\. How should significant degradation be evaluated for pollutants

where no numeric criterion has been adopted?

10\. Is additional Agency guidance or regulatory requirements

necessary to help States and Tribes address social and economic

importance (e.g., additional methods or options beyond those discussed

in the March 1995 Interim Economic Guidance document)?

11\. Should evaluating the importance of proposed discharges be

entirely a State or Tribal determination and not be a required element

for EPA review?

12\. Would it be appropriate to revise the regulation to clarify the

relationship between nonpoint source controls and tier 2

antidegradation requirements?

13\. Should EPA revise the regulation to expressly state that States

and Tribes are to consider the 303(d) listing status of a water body,

and the information supporting that status, when determining whether a

proposed activity that is expected to degrade water quality in that

water body can be authorized under tier 2 of the State\'s or Tribe\'s

antidegradation provisions?

14\. Is greater consistency between individual State and Tribal

programs desirable and, if so, what changes may be needed to the

regulation or EPA guidance to ensure that the tier 2 provision is

implemented in a nationally consistent manner?

5\. 40 CFR 131.12 (a)(3) \`\`Tier 3\'\'

Tier 3 of the antidegradation policy is intended to identify and

protect waters of extraordinary ecological, recreational or other

significance. Tier 3 of the antidegradation policy incorporates the

\[\[Page 36786\]\]

concept of Outstanding National Resource Waters (ONRW). The rationale

for this provision is that some water bodies are of such high quality

or of such exceptional ecological significance that the commonly

applied designated uses such as warm water fishery and primary contact

recreation and criteria to protect those uses are not suitable or may

not provide adequate protection to maintain the high water quality or

ecological significance in a given water body.

ONRWs are intended to include the highest quality waters of the

United States. Additionally, the ONRW antidegradation classification

offers special protection for waters of \`\`exceptional ecological

significance,\'\' i.e., those water bodies which are important, unique,

or sensitive ecologically, but whose water quality, as measured by the

traditional characteristics such as dissolved oxygen or pH, may not be

particularly high, such as thermal springs. Waters of exceptional

ecological significance also include waters whose characteristics

cannot adequately be described by traditional parameters (such as

wetlands and estuaries).

Tier 3 of the antidegradation policy provides the highest level of

protection to water bodies by prohibiting the lowering of water

quality. The only exception to this prohibition as discussed in the

preamble to the water quality standards regulation is for activities

that result in short-term and temporary changes in the water quality of

the ONRW. EPA guidance has not defined temporary and short-term

specifically, but views these terms as limiting water quality

degradation for weeks or months, not years. The intent is to limit

degradation to the shortest possible time.

a\. Designating ONRWs. The designation of water bodies as ONRWs has

been limited in its application. Overall, there are relatively few

water bodies designated as ONRWs in the United States, although some

States have designated a high percentage of State waters as ONRWs.

Several States have been reluctant to adopt ONRWs because of concerns

regarding the process for adopting ONRW classifications and the level

of protection afforded to a water once it is classified as an ONRW.

Regarding the process for adoption of ONRWs, the existing

regulation requires the State or Tribe to provide an ONRW level of

protection in their antidegradation policies, but there is no

requirement that any water body be so designated or any specificity as

to how that is to be done. One way to address this issue may be for EPA

to amend the regulation to require States and Tribes to establish a

nomination process with criteria guidelines in which the public could

petition the State or Tribe for designation of certain waters as ONRWs.

It would then be up to the State or Tribe to set criteria for the ONRW

selection process with the final decision made by the State or Tribe

after consideration of the public comment. EPA currently recommends

three categories of waters which could be eligible for ONRW

designation: waters of (1) National and State parks, (2) wildlife

refuges, and (3) exceptional recreational or ecological significance.

Regarding the level of protection that is afforded to a water body

once it is classified as an ONRW, a common concern is that classifying

a water as ONRW will result in a federal prohibition on any further

development of any kind in the watershed. As described above, the

federal antidegradation policy regarding ONRWs is that once classified

as an ONRW, the water quality of the ONRW must be maintained and

protected. One way, but perhaps not the only way, to ensure that the

water quality is maintained and protected would be to prohibit

activities that would generate additional pollutant loads and or water

quality impacts in the ONRW. This approach is commonly referred to as

\`\`no new or increased discharge\'\' and was explained by EPA in its

promulgation of antidegradation provisions for the State of

Pennsylvania in 1996 (61 FR 64816, December 9, 1996). As discussed in

the Pennsylvania rule, the federal policy requiring the water quality

to be maintained and protected is subject to some interpretation by

States and Tribes.

EPA believes there is considerable uncertainty from jurisdiction to

jurisdiction concerning the impact of the ONRW classification on the

local community or the State or Tribe. How will the State or Tribe

handle future needs for development in the area of the ONRW? What role

does EPA play in ensuring that the State or Tribe provides the highest

protection measures to ONRWs? EPA\'s current thinking is that this
\`\`no

further development in the watershed prohibition\'\' may be an overly

strict interpretation of the protection required by tier 3 and that a

public debate is necessary to clarify the level or range of protection

that is afforded to a water by classifying it as an ONRW, and how that

level or range should be determined.

One way to remove uncertainty surrounding the implications of ONRW

designations is for States and Tribes to adopt concurrent with the ONRW

the implementation methods for that water body that define what

attributes of the water will be protected and how this will be

accomplished by both point and nonpoint sources. It may make sense for

the regulation to include this requirement in order for all parties

concerned to know the impact on development of such a designation

before adopting an ONRW.

i\. Relationship of Tier 3 to the Wild and Scenic Rivers Act.

Additionally some States have not adopted waters as ONRWs when there

has been concern regarding ONRW requirements and the requirements of a

wild, scenic, or recreational water body. Although the Department of

Interior (DoI) founded the antidegradation policy from which the

concept of an outstanding national resource water (ONRW) that EPA

currently uses evolved, an ONRW is different from the Wild and Scenic

Rivers program administered by DoI. ONRWs are designated by the State

or Tribe in their water quality standards. Wild and scenic rivers are

given their designation by Congress or the Department of Interior

pursuant to the Federal Wild and Scenic Rivers Act. The main purpose of

the Wild and Scenic Rivers Act is to keep waters free-flowing. The main

purpose of an ONRW designation is to maintain and protect high quality

waters that constitute outstanding resources due, for example, to their

exceptional recreational or ecological significance, which can include

free-flowing water. EPA does not see any conflict between these two

programs.

b\. Tier 3 Implementation. EPA in chapter 4 of the Water Quality

Standards Handbook interprets the \`\`water quality to be maintained and

protected\'\' provision of the regulation as requiring no new or

increased discharges to ONRWs and no new or increased discharge to

tributaries to ONRWs that would result in lower water quality in the

ONRWs. The only exception is for short-term and temporary changes. In

contrast, some States, Tribes, and EPA Regions have interpreted this

provision to allow new discharges as long as the water quality is

either maintained or improved. Alternatively, some States, Tribes and

Regions have interpreted water quality in terms of the characteristics

for which the water body was selected to be an ONRW and have strictly

maintained those characteristics while allowing other characteristics

to become degraded. EPA has also allowed a proposed activity that will

result in a new or expanded source where the applicant agrees to

implement or

\[\[Page 36787\]\]

finance upstream controls of point or nonpoint sources sufficient to

offset the water quality effects of the proposed activity. This offset

is generally called trading and is accomplished through a TMDL pursuant

to CWA Section 303(d) requirements. Such TMDLs include an appropriate

margin of safety and address, in particular, the uncertainties

associated with any proposed nonpoint source controls, as well as

variability in effluent quality for point sources.

This variability in interpretation has created ONRWs across the

Nation that vary in terms of the stringency of point source controls,

and types of water bodies considered to be ONRWs. Restrictions on

physical changes have also been implemented in an inconsistent manner.

EPA is considering whether the existing ONRW protection program is

addressing an appropriate universe of waters and whether the

flexibility provided under the regulation, in terms of coverage and

protection requirements, needs to be further restricted, maintained, or

expanded. It may make sense to have an ONRW designation which is

permanent and allows no change in water quality and applicable to few

waters while creating a subset of waters which can have some change in

water quality under certain circumstances.

c\. Tier 2\\1/2\\. Several States and Tribes have already created, as

part of their antidegradation policy, a provision that is in between

EPA\'s recommended tier 2\--high quality waters and tier 3\--
Outstanding

National Resource Waters, sometimes referred to as Tier 2\\1/2\\. This

additional tier is given various names, such as Outstanding State

Resource Waters, Outstanding Tribal Waters, Special Protection Waters,

or Water of Exceptional Significance. When it supplements tier 2 and

tier 3 provisions, EPA has accepted this provision as being consistent

with the intent and spirit of the antidegradation policy. Inclusion of

a tier 2\\1/2\\ within the regulation would encourage States and Tribes

to apply more stringent controls than would be required under tier 2

but with more flexibility to make adjustments in criteria and

permitting decisions than would normally be allowed if the water body

in question were designated as an ONRW. Any additional flexibility that

might be created by a tier 2\\1/2\\ classification to allow additional

activities that could marginally affect water quality, might not be

necessary where a State or Tribe (or EPA) considers such flexibility to

already exist in the context of the ONRW classification. In commenting

on the flexibility afforded by the tier 2\\1/2\\ classification,

commenters are urged to state their understanding of the flexibility

currently afforded in the ONRW classification.

Request for Comments on Antidegradation Tier 3

EPA seeks comment on the following questions:

1\. Should EPA add definitions of important terms to the ONRW part

of the regulation, including a definition of \`\`degradation\'\' which

clarifies that temporary or short-term effects on ONRW waters could be

authorized? Should definitions of \`\`short-term\'\' and
\`\`significant\'\'

also be included?

2\. Should EPA require States and authorized Tribes to establish

both a process and qualification criteria which would allow the public

to nominate waters for the ONRW designation? Would EPA guidance be

helpful?

3\. Should the tier 2\\1/2\\ antidegradation policy concept be

explicitly recognized in the federal regulation and what, if any,

limits or factors for application of the tier should be included?

4\. States (and Tribes) have differing interpretations of the level

of protection afforded ONRWs. Should EPA further specify in the

regulation what maintaining and protecting water quality in ONRWs

means?

6\. 40 CFR 131.12 (a)(4) \`\`Thermal Discharges\'\'

The requirement to prevent potential water quality impairment

associated with thermal discharges contained in Sec. 131.12 (a)(4) of

the regulation is intended to coordinate the requirements and

procedures of the antidegradation policy with those established in the

CWA for setting thermal discharge limitations. Regulations implementing

section 316 may be found at 40 CFR 124.66. The statutory scheme and

legislative history indicate that limitations developed under section

316 take precedence over other requirements of the CWA. EPA is not

requesting comment on this section of the regulation. This provision is

mentioned here only in the interest of completeness.

E. Mixing Zones

1\. Background

The current regulation (at 40 CFR 131.13) describes States\' and

Tribes\' discretionary authority to include, in their water quality

standards, policies that affect the implementation of those standards.

For example, States and Tribes may adopt policies on mixing zones,

variances, and schedules of compliance for water quality-based NPDES

permit limits. If included in their water quality standards or other

implementing regulations, States and Tribes are required to submit such

policies to EPA for review and approval. The policies governing the

implementation of water quality standards are inseparable from the

standards themselves and, consequently, EPA reviews both to determine

whether implementation policies are compatible with the State or Tribal

water quality standards provisions, technically well founded and

consistent with the CWA.

Concerns have been expressed both by the regulated community and

environmental groups over the lack of specificity in State and Tribal

mixing zone policies and implementation procedures adopted under this

general policies provision. These groups believe that this lack of

specificity may result in rather subjective and inconsistent

implementation of water quality standards, from site-to-site. EPA has

also, through its ten regional offices, not always applied uniform

standards in reviewing individual States\' and Tribes\' mixing zone

provisions.

In encouraging the implementation of water quality management

activities consistent with a broader watershed approach, EPA has

encountered inconsistent implementation of mixing zone provisions

across State and Tribal borders, within whole watersheds, and sometimes

along a single water body. Remedies to water quality problems designed

along watershed boundaries can be limited in their effectiveness as a

result of differing policies, procedures and treatment of the same

water body by different authorities. A certain amount of flexibility

is, however, essential when dealing with complex water quality problems

on a watershed or basin scale. EPA\'s current thinking is that it is

preferable to be more explicit about where the program requires

consistency and where flexibility is allowed or encouraged.

The current regulation does not articulate any EPA requirements

regarding the content of mixing zone implementation procedures. Rather,

EPA guidance addressing mixing zones, and stream design flows is

contained in several documents, including the Water Quality Standards

Handbook: Second Edition (the Handbook) and the Technical Support

Document for Water Quality-based Toxics Control, March, 1991 (the TSD).

Although program and technical guidance identifies the approaches to

standards implementation which EPA recommends and considers protective

of water quality, guidance is not equally effective at delineating what

constitutes

\[\[Page 36788\]\]

minimally acceptable content or the approaches EPA considers to be not

approvable or inconsistent with the CWA. Further, most regulatory

agencies, as well as the regulated community, are most concerned with

what is required rather than what is recommended. Policy or guidance is

not binding whereas regulation is. Guidance is better designed to

provide detailed descriptions of the variety of technically sound

implementation approaches and their underlying scientific basis;

regulation provides the clearest direction regarding required minimal

program content and identification of those components of the program

where flexibility is allowed.

EPA is considering an expansion of the section of the regulation

addressing general policies to provide clear, detailed and specific

direction to States and Tribes on the development and content of mixing

zone policies and implementation procedures. EPA\'s current thinking is

that greater specificity within this portion of the regulation may be

needed to clarify the minimum necessary elements of State and Tribal

mixing zone policy and implementation procedures. EPA\'s current

thinking is that this area of the regulation needs to articulate a

clear level of national consistency in mixing zone implementation that

results in a consistent level of protection across the country and at

the same time, where State and Tribal flexibility is not only

encouraged, but possibly essential to program efficiency and accuracy.

2\. EPA Policy and Guidance on Mixing Zones

The concept of mixing zones as a regulatory tool to address the

incomplete mixing of wastewater discharges in receiving waters has been

embraced by both EPA and its predecessor agencies as part of a larger

regulatory effort to ensure that point source discharges of wastes do

not impair beneficial uses. EPA interprets the CWA as allowing the use

of mixing zones as long as the provisions addressing toxicity at

section 101(a)(3) are met and the designated uses of the water body as

a whole are protected. One court has considered the application of a

mixing zone in a discharge permit and upheld EPA\'s use of a limited

mixing zone (See Hercules v. EPA, 598 F.2d 91 (D.C. Cir. 1978)). The

concept of a mixing zone is covered by a series of guidance documents

issued by EPA and its predecessor agencies (see, for example: Water

Quality Criteria (Green Book), Federal Water Pollution Control

Administration, 1968, pp. 29-31; Water Quality Criteria 1972 (Blue

Book), EPA, March 1973, pp. 112-115, 231-232, 403-457; Guidelines for

Developing or Revising Water Quality Standards, January 1973; Chapter

5\--Guidelines for State and Areawide Water Quality Management Program

Development, November, 1976; Allocated Impact Zones for Areas of Non-

Compliance, EPA Region 1, October 1986; The Water Quality Standards

Handbook, August, 1994, pp.5-1 to 5-11; Technical Support Document for

Water Quality-based Toxics Control (TSD), March, 1991, pp. 31-34, 56-

60, 69-89).

Many definitions of mixing zones have been offered, differing

primarily by perspective (i.e., engineering, hydrological, ecological,

regulatory) and their application. From a hydrological/engineering

perspective, mixing zones can be defined based upon the recognition of

incomplete mixing of an effluent with its receiving water (e.g.,
\`\`that

area or volume of dilution water necessary to reduce contaminant

concentrations to some acceptable level or to a totally mixed

condition\'\'). Biologically, mixing zones can be defined based on the

premise that surface water quality criteria can be exceeded under

limited circumstances without causing unacceptable toxicity or, more

broadly, impairment of the designated beneficial uses (e.g., \`\`the
area

contiguous to a discharge where receiving water quality is not required

to meet water quality criteria nor other requirements applicable to the

receiving water\'\').

EPA\'s policy on the use of mixing zones has evolved since its early

recognition within general water quality guidance, primarily in

association with the institution and evolution of the NPDES permit

program (e.g., the TSD). Initially, guidance emphasized the need to

ensure that the biological integrity of the aquatic community in the

receiving stream was protected and that such determinations must be

based on site-specific evaluations. In the late 1980\'s EPA and

authorized NPDES States began increasing the development and issuance

of water quality-based effluent limits. With this increase, came a

demand for widely applicable national guidance to support those

programs. EPA and States, in essence, needed wasteload allocation and

water quality-based permit limit derivation methods that were

relatively simple to use and could be implemented with little site-

specific data. EPA met this demand by issuing revised guidance (the TSD

and Handbook, cited above, are examples) and by accepting a wide range

of State mixing zone practices. As a result, mixing zone provisions

have become less prescriptive than earlier guidance that envisioned

data rich, site-specific studies, and more reliant on often cursory

evaluations, general mixing assumptions, and best professional

judgement.

EPA\'s current policy addresses mixing zones as allocated impact

zones (AIZs) where certain numeric water quality criteria may be

exceeded as long as: there is no lethality to organisms passing through

the mixing zone, there are no significant risks to human health, and

the designated and existing uses of the water body are not impaired as

a result. These AIZs or mixing zones, if disproportionately large,

could unacceptably impact the integrity of the aquatic ecosystem and

have unanticipated ecological consequences on the water body as a whole

resulting in impairment of the designated or existing uses. Therefore,

EPA\'s policy has emphasized a holistic approach to mixing zone

regulation which considers location, size, shape, outfall design and

in-zone quality. Mixing zone guidance produced by EPA since 1972 has

consistently emphasized the need to protect both nonmotile benthic and

sessile organisms in the mixing zone as well as swimming and drifting

organisms (Water Quality Criteria 1972). States and Tribes, however,

have focused primarily, if not exclusively, on the protection of

swimming and drifting organisms and the need to provide \`\`zones of

passage\'\' within waters with mixing zones. In its dependence upon

conditions protective of swimming and drifting organisms to define

mixing zones, this approach results in an incomplete implementation of

the original concept supporting mixing zones. As originally designed,

EPA\'s mixing zone policy provided for the prevention of lethality to

swimming and drifting organisms by limiting the size of the mixing zone

and to nonmotile organisms by limiting the placement or location of

mixing zones.

Although existing EPA guidance on the implementation of mixing

zones (cited above) is quite detailed, at present, the regulation

itself simply provides that States and Tribes may adopt, as part of

their water quality standards, mixing zone policies and that such

policies are subject to EPA review and approval (40 CFR 131.13). In

addition, EPA may separately review individual State and, once approved

to administer NPDES, Tribal mixing zone determinations as part of the

wasteload allocation and NPDES permit review process, outside the

standards adoption and review process to ensure appropriate

implementation of the State\'s mixing zone policy.

\[\[Page 36789\]\]

EPA is considering expanding the current provisions at 40 CFR

131.13 addressing State and Tribal development of mixing zone policies

within their water quality standards program to address the content and

design of those policies.

3\. State and Tribal Mixing Zone Policies

While there are advantages to the more flexible general approach

adopted in the late 1980\'s, the generality of the current regulation

has led to some uncertainty as to what constitutes an approvable mixing

zone policy. Because the regulation lacks detailed requirements

concerning EPA\'s standards of review of State and Tribal mixing zone

provisions, EPA is considering changing the language regarding State

and Tribal adoption of mixing zone policies to address specifically the

content of such policies. EPA\'s current thinking is that greater

specificity would provide for increased public participation in State,

Tribal and Federal decision-making; a clearer understanding by the

State, Tribe and public of what EPA considers an approvable mixing zone

policy; a reduction in the number of NPDES permit appeals and

objections based on differing interpretations of a State or Tribal

mixing zone policy; and a more consistent review of State and Tribal

submissions by EPA itself.

Fundamental to any such policy, EPA is considering requiring States

and Tribes to indicate explicitly in their water quality standards

whether or not they allow mixing zones for each of the various uses

designated for a given water body. Such provisions could address mixing

zones applied to either acute or chronic aquatic life and other water

quality criteria (e.g., public water supply, livestock watering,

wildlife protection, etc.). Under this approach, if the State or Tribe

does not explicitly authorize mixing zones, then no mixing zones would

be allowed in State or Tribal waters, and all applicable criteria would

have to be met at the end-of-pipe. (Memorandum from Robert Perciasepe,

Assistant Administrator for Water to Water Program Directors, Regions

I-X, Subject: EPA Guidance on Application of State Mixing Zone Policies

in EPA-Issued NPDES Permits, August 6, 1996). Alternatively, States and

Tribes could determine that such prohibitions would be applied to only

a subset of uses or pollutants rather than across all use categories

and pollutants. Some States or Tribes have used this approach to

prohibit mixing zones in their highest use classes (e.g., class AA),

while allowing mixing zones in more highly impacted watersheds (e.g.,

class C or D waters).

States and Tribes could also be required to specify the conditions

under which mixing zones are allowed in each site-specific application

and the limitations to those applications (e.g., size, shape, length,

placement, etc.). In addition, States and Tribes could be required to

identify any circumstances, pollutants, locations or conditions for

which the use of mixing zones is prohibited. States and Tribes could

specify circumstances where only chronic mixing zones would be allowed

(i.e., no acute mixing zone or zone-of-initial dilution) and

circumstances where acute and/or chronic mixing zones would be

prohibited. Current EPA guidance, for example, recommends States and

Tribes consider prohibition of mixing zones when bioaccumulative

pollutants are present in the discharge or where an effluent is known

to attract biota. Other circumstances where mixing zone prohibitions or

location restrictions might be appropriate include areas used by

aquatic life for breeding or feeding, locations of shellfish beds,

locations of critical habitat for threatened and endangered species,

across tributary mouths, shallows, near shore areas and in areas of

critical habitat.

This change would clarify in the regulation the State and Tribal

general authority to provide mixing zones, the scope of that authority,

and the site-specific factors evaluated by States and Tribes when

deciding whether a mixing zone is authorized in each individual case.

EPA is considering making this potential clarification to the

regulation, its implications, and how mixing zone policies can be

designed to better support and foster a watershed management framework.

4\. Mixing Zone Requirements

Some States and Tribes that have adopted mixing zone provisions

within their water quality standards have not specified mixing zone

requirements (e.g., water quality within mixing zones, the allowable

size of mixing zones, etc.) under their mixing zone policies. EPA is

therefore considering including as regulatory requirements certain

specifications derived from EPA\'s guidance on mixing zones. Regarding

policy content, EPA might revise the regulation to require that State

and Tribal mixing zone policies address a minimum number of elements.

Those required elements might include provisions that: identify

conditions and circumstances (e.g., particular locations) when mixing

zones are not permitted; identify any pollutants or classes of

pollutants for which mixing zones are prohibited; identify the

mechanisms to be used to ensure that mixing zones do not impinge on

ecologically or recreationally sensitive areas; identify the mechanisms

to be used to determine complete and incomplete mixing of effluent and

receiving water; identify conditions when a mixing analysis is

required; identify default design flows for implementing criteria;

identify maximum allowable mixing zone size and configuration, as well

as how mixing zones dimensions are determined; specify what water

quality conditions must be met within mixing zones; state whether zones

of initial dilution are allowed; and state whether there are special

conditions established for bioaccumulative pollutants.

Identification in the regulation of minimum elements of State or

Tribal mixing zones procedures would establish the basis for EPA review

and approval of State and Tribal mixing zone provisions. It would also

facilitate the review of individual mixing zone determinations made

under the wasteload allocation/permit approval process by EPA, other

agencies and the public. This would not significantly change EPA\'s

guidance or current approach to mixing zone policies. Rather, it would

clarify and codify the basis by which EPA will review and approve or

disapprove State and Tribal mixing zone policies and their site-

specific implementation through NPDES permits.

As discussed previously, EPA\'s mixing zone guidance is premised

fundamentally on the prevention of lethality within the mixing zone and

siting such that areas of critical habitat are avoided, resulting in

the protection of designated uses. One aspect of this guidance is that,

for aquatic life uses, water quality within the mixing zone should be

such that, at a specified concentration of a contaminant (i.e.,

magnitude), any \`\`swimming or drifting\'\' organism would not remain
in

the mixing zone long enough to receive an exposure that is sufficiently

long (i.e., duration) to cause lethality. If the combination of the

concentration of a given pollutant or the combined effect of multiple

pollutants (e.g., whole effluent toxicity) in a discharge and the

duration of exposure to that concentration are low enough, there is no

lethality within the mixing zone, and the criteria (magnitude and

duration components together) are met.

This approach, however, only provides protection in situations in

which water column organisms pass in and out of the mixing zone. This

interpretation does not adequately

\[\[Page 36790\]\]

protect stationary or sessile organisms within the mixing zone;

organisms that remain within the mixing zone for extended periods

because the mixing zone extends into feeding or breeding areas or

critical habitat (e.g., tributary mouths, shallows, shoreline habitat

in large, fast-flowing rivers); critical habitat areas for endangered

or threatened species; or instances where mixing zone conditions

attract organisms. EPA\'s mixing zone policy and guidance address those

instances where the provisions protecting swimming and drifting

organisms are not adequate to protect nonmotile benthic and sessile

organisms or critical habitat areas by limiting the location, size and

shape of mixing zones. In some instances, this policy has been

implemented in a fragmented manner. In such instances, these latter

restrictions to mixing zone placement are inadequately addressed. EPA

always has discretion to object to, and take over if necessary, permits

that provide site-specific mixing zones in cases where such mixing

zones would fail to protect all aspects of designated uses. However,

oversight of individual permits is not an efficient approach to

resolving program-level issues. To clarify the meaning of its policy

and ensure a more complete implementation of protective mixing zone

provisions, EPA is considering changes to the regulation.

EPA could require that State and Tribal mixing zone policies

specifically identify prohibitions (where appropriate) or limit mixing

zones where necessary to protect existing or designated uses. Some

States and Tribes already include prohibitions against the use of

mixing zones where they could intrude upon public drinking water supply

intakes or public swimming beaches, or where mixing zones prove to be

attractive to aquatic life or wildlife (e.g., water temperature). EPA

might require that State and Tribal mixing zone provisions specifically

address instances such as these where restrictions on mixing zones are

appropriate. Additionally, EPA is considering requiring that State and

Tribal water quality standards include a description of the State\'s or

Tribe\'s methodology for specifying the location, geographic boundaries,

size, shape and in-zone quality of mixing zones.

EPA could also clarify its current policy that an approvable mixing

zone methodology must be scientifically defensible and ensure the

protection of designated uses in the water body as a whole. This would

require that the methodology, at a minimum, be sufficiently precise to

support consistent regulatory actions (e.g., an NPDES permit). EPA is

considering this change to ensure that State and Tribal mixing zones do

not adversely affect the integrity of State and Tribal waters and to

address inconsistent allocation of mixing zones from site-to-site.

Under this approach, for example, when a State or Tribe assumes that

either complete or incomplete mixing occurs, the State\'s or Tribe\'s

implementation procedure could require the analyses supporting the mix

assumption to be documented in the record (e.g., permit fact sheet).

EPA is considering the need for additional language in the water

quality standards regulation to clarify the essential elements of State

or Tribal mixing zone provisions and, alternatively, whether such

language would be better established in guidance. EPA\'s current

thinking is that a certain amount of professional judgement is

necessary in making site-specific mixing zone determinations and that

clarifications to the regulation regarding the minimum mixing zone

policies and implementation procedures should not preclude such

flexibility. However, the policy and implementation procedures should

be clarified so that the guidelines and framework for making site-

specific mixing zone determinations are clear to everyone.

5\. Mixing Analyses

The above discussion focuses on establishing State and Tribal

mixing zone policies and procedures. The following discussion addresses

the application of such procedures in individual permitting decisions.

Where point source discharges mix in a slow or \`\`incomplete\'\'

manner with receiving waters and the State or Tribe has authority to

provide a mixing zone, EPA guidance recommends that a mixing zone

analysis be incorporated into the derivation of water quality-based

effluent limits (WQBELs) in NPDES permits. The mixing zone analysis

should demonstrate compliance with State or Tribal mixing zone

requirements (e.g., size, shape, location and in-zone quality) that are

included in the water quality standards. Providing a mixing zone in

incomplete-mix situations acknowledges the mixing behavior of the

discharge and limits excursions above criteria to a specified zone.

Where a discharge mixes with the receiving water in a rapid and

\`\`complete\'\' manner, by definition a mixing zone analysis is not
needed

and an evaluation of the assimilative capacity of the receiving water

and a dilution allowance based on stream design flow conditions

specified in the State or Tribal water quality standards is often

incorporated into the derivation of WQBELs.

Presently, all State-issued NPDES permits are reviewable by EPA.

EPA may object to individual permits and assume authority to issue such

permits. When EPA is the permit issuing authority, it must follow the

applicable State or Tribal water quality standards and ensure that any

water quality-based effluent limits in the permit are derived from and

comply with the applicable State or Tribal water quality requirements.

A permit that does not include a defensible mixing zone analysis might

not fully protect downstream designated uses. A common example is where

a discharge mixes slowly (i.e., incomplete mixing is occurring), but

the permit limit is based on an assumption that the entire design flow

of the stream rapidly and completely dilutes the effluent. When this

does not occur and not all of the dilution water mixes rapidly with the

effluent discharge, the result may be a lengthy downstream plume (i.e.,

mixture of effluent and surface water) with water quality

characteristics that exceed applicable chemical-specific or toxicity

criteria, are potentially lethal to aquatic life, and may impair the

designated use. Such plumes are of concern because:

\(1\) Chemical-specific criteria, ambient toxicity criteria or other

narrative criteria may not be achieved in the extended plume;

\(2\) Effluent plumes can extend far downstream, causing impact

beyond the limited area of a mixing zone and resulting in use

impairment;

\(3\) There may be intakes for public drinking water systems located

downstream, but within reach of an extended plume;

\(4\) Effluent plumes may be located along the shore in shallow

waters that are critical nursery areas for sensitive species and which

constitute important or critical habitat, particularly in large,

channelized rivers;

\(5\) Aquatic life might be attracted to the plume because of its

temperature differential or other characteristics;

\(6\) Threatened or endangered species may reside within or near the

plume area, and

\(7\) Additional dischargers may be located downstream and the

cumulative effects of all discharges may not be adequately considered,

particularly regarding unintended overlapping plumes.

EPA believes the rate of ambient mixing and the complete versus

incomplete mix decision is a critical but frequently overlooked

component of water quality-based permitting.

\[\[Page 36791\]\]

Although a mixing zone analyses requires site-specific information and

additional resources, EPA believes that the approach currently followed

by some States and Tribes might be too simplistic, might allow

lethality within areas of critical habitat or ecological importance and

may not fully protect designated uses. EPA\'s current thinking is that

the regulation should be made more explicit as to the circumstances

under which mixing zones must be supported by site-specific data and

analysis. EPA is considering the need for specific requirements within

the regulation governing the development and content of mixing zone

analysis procedures as part of State and Tribal implementation

procedures.

6\. Narrative Criteria for Mixing Zones

Historically, States have relied on narrative criteria as a means

to provide baseline protection for water quality, to address toxicity

from combinations of pollutants or unknown pollutants through whole

effluent toxicity testing and limits, and to control pollutants for

which there are no chemical-specific criteria available. EPA has

consistently maintained that prevention of nuisance conditions (e.g.,

materials that will settle to form objectionable deposits, floating

debris, oil, scum, foam and other matter, toxic conditions, etc.),

through the application of narrative criteria, apply to all waters, at

all times, including mixing zones. Despite this long-standing policy,

EPA is unaware if, in practice, States and Tribes have had any

difficulty ensuring the maintenance of these narrative criteria within

mixing zones. EPA is interested in comment which might identify any

instances where the application of narrative criteria has created

difficulties for States and Tribes implementing these provisions in

mixing zones.

In addition, EPA has traditionally interpreted these narrative

\`\`free froms\'\' as including a prohibition against lethality in all

waters, including within mixing zones. However, lethality is a non-

conservative endpoint for measuring toxicity. Section 101(a)(3) of the

CWA establishes a goal of prohibiting \`\`the discharge of toxic

pollutants in toxic amounts\'\' which could be interpreted as applying
to

chronic as well as acute toxicity. EPA guidance on appropriate water

quality within mixing zones also recommends that \`\`the total time-

toxicity exposure history must not cause deleterious effects in exposed

populations of important species, including post-exposure effects\'\'

(EPA, 1973). EPA is considering how such an interpretation (i.e.,

applying chronic toxicity endpoints to water quality within a mixing

zone) could be implemented in the context of the application of

narrative criteria within a mixing zone.

Guidance developed by EPA in 1985 (TSD) established a rationale for

allowing zones-of-initial-dilution (ZIDs) or acute mixing zones. That

guidance limited the use of ZIDs to extremely small areas of the

receiving water under limited conditions and to discharges using rapid

diffusers which produce effluent discharge velocities exceeding 10 feet

per second. That guidance was premised on the rationale that organisms

would be physically precluded from maintaining a position within the

ZID, thus preventing lethal exposures. Benthic and sessile organisms

were also protected where ZID placement was controlled and directed

away from such critical areas (e.g., near shore, shallows, etc.). In

addition, EPA reasoned, high rate diffusers achieve compliance with

both acute and chronic criteria within a smaller area, utilizing less

receiving water volume for dilution than other discharge designs.

Consequently, high rate diffusers are believed to provide greater

protection of water quality by their rapid dispersion of effluent

within a smaller volume of surface water. Where acute criteria are not

applied at the end-of-pipe, current EPA guidance provides for a number

of alternative means of protecting against lethality in a mixing zone,

even in situations that do not rely on high rate diffusers.

Alternatives to requiring compliance with acute criteria at the end-of-

pipe or employing a high-rate diffuser to ensure compliance \`\`within a

very short distance from the outfall\'\' require a significant amount of

site-specific data. Such site-specific data could be requested of NPDES

permit applicants. It is EPA\'s experience that the collection of this

kind of data does not occur on a routine basis. EPA is interested in

public comment on the relationship between ZIDs or acute mixing zones

and narrative criteria prohibitions against lethality and States\' and

Tribes\' experiences with the application of acute mixing zones under

varying site-specific and discharge-specific conditions. EPA is also

interested in comments on whether the water quality benefits of using

high rate diffusers justify potentially detrimental effects on stream

bed or shore line habitat.

7\. Mixing Zones for Bioaccumulative Pollutants

States and Tribes should exercise caution when evaluating whether a

mixing zone is appropriate in cases where bioaccumulative pollutants

are present. The impacts of bioaccumulative compounds may extend beyond

the boundaries of a given mixing zone with resulting impairment of a

water body\'s designated uses, particularly where stationary species

(e.g. shellfish) are present, where uncertainties exist regarding the

assimilative capacity of a water body or where bioaccumulation in the

food chain is known to be a problem. Sediment contamination has also

become a major concern in both flowing and non-flowing water bodies.

Concerns about sediment contamination require additional attention

since typical mixing zone evaluations focus only on water column

toxicity. The effects of persistent and bioaccumulative pollutants may

not be detected for some distance from the point of discharge, well

outside the mixing zone, or possibly not in the water column at all.

Some members of the public have expressed concern regarding the use of

mixing zones in situations where bioaccumulative pollutants are present

in a discharge and have urged EPA to develop specific regulatory

requirements prohibiting the use of mixing zones where these pollutants

are present.

Mixing zone policies are developed to address complete and

incomplete mixing conditions associated with point source discharges.

These policies identify whether mixing zones are allowed and define how

a State or Tribe will limit the amount of surface water allocated to

mixing under a variety of circumstances. These circumstances include

considerations specific to the effluent and pollutants discharged

(e.g., toxicity, solubility) and to the water body receiving the waste

(e.g., shallow, flowing or non-flowing, high flow or low flow, critical

habitat). The potential for bioaccumulation problems can depend on a

number of site-specific factors and the use of mixing zones for

bioaccumulative pollutants may be best dealt with on a site- or basin-

specific basis. EPA\'s mixing zone guidance emphasizes that the

determination by a State or Tribe that a mixing zone is appropriate

must be preceded by a separate determination that there is available

assimilative capacity in the receiving water. Localized water quality

concerns are to be balanced with the larger scale issue of overall

pollutant loading to the entire water body or segment. Perhaps concerns

about the fate and transport of bioaccumulative pollutants are more

effectively addressed under total maximum daily load (TMDL) development

and determinations of assimilative capacity which incorporate

information on water

\[\[Page 36792\]\]

column, sediment and tissue contamination. EPA is considering the

appropriateness of using mixing zones when controlling for

bioaccumulative pollutants.

As discussed in more detail in Section C of this Notice, EPA has

recently developed methodologies for deriving sediment quality criteria

for non-ionic organics and metals and has proposed sediment quality

criteria for five organics. In addition, EPA is working on

implementation procedures or a \`\`user\'s guide\'\' for these sediment

criteria which will address risk management decisions such as the

application of mixing zones.

The regulatory impact of special restrictions on mixing zones for a

particular family of pollutants is largely determined by how that

family of pollutants is defined within the regulation. The issue of

definition of bioaccumulative pollutants is also addressed in the

discussion of water quality criteria in Section C of this notice.

In its Great Lakes Guidance, EPA established a twelve year phase

out of mixing zones for existing discharges of bioaccumulative

chemicals of concern (BCCs) in the Great Lakes Basin and a ban on such

mixing zones for new discharges (effective March 1997). The Great Lakes

Guidance also allowed States and Tribes to establish limited exceptions

to the mixing zone phase-out for existing discharges based on water

conservation or economic and technical considerations. The general

prohibition on mixing zones for BCCs was established largely because of

the persistent and toxic nature of even minute amounts of BCCs in the

environment; an effect amplified in the Great Lakes by the tendency of

the Lakes to act as \`\`sinks\'\' for pollutants discharged to the Great

Lakes Basin. In addition, there are documented problems with effects of

BCCs in Great Lakes waters (e.g., contamination of Great Lakes salmonid

sport fisheries with PCBs and Basin-wide mercury contamination). The

Great Lakes Guidance provision phasing out mixing zones for BCCs

reflected the Agency\'s thinking that, in general, mixing zone

allowances for BCCs are not appropriate.

On June 6, 1997, the United States Court of Appeals for the

District of Columbia Circuit issued its decision in American Iron and

Steel Institute, et al. v. EPA, 115 F.3d 979 (D.C. Cir. 1997). The

Court\'s decision upheld the Great Lakes Guidance on all but three

issues. One of these three issues was the phase out of on mixing zones

for BCCs. Specifically, the Court vacated the final Guidance insofar as

it would eliminate mixing zones for bioaccumulative chemicals of

concern (BCCs). While the Court acknowledged the possibility of

environmental benefit of the mixing zone provisions, the Court found

that EPA failed to show that the provisions were justified in light of

the costs. EPA continues to support elimination of mixing zones for

BCCs within the Great Lakes Basin wherever it is technically and

economically feasible to do so. Thus, EPA intends to propose

reinstating this provision in the near future.

8\. Stream Design Flow Policies

States and Tribes typically identify, within their water quality

standards, stream design flow conditions to implement numeric water

quality criteria. The stream flow conditions are typically expressed as

predictable low flow conditions below which numeric water quality

criteria do not apply. Examples of commonly used stream design flows

include: the lowest seven consecutive day average stream flow that has

the annual probability of occurring once in ten years (7Q10); the

lowest single day stream flow that has the annual probability of

occurring once in ten years (1Q10); and the harmonic mean stream flow.

The stream design flows typically employed with aquatic life criteria

(i.e., 7Q10 and 1Q10), sometimes referred to as critical low flows or

drought flows, are intended to define stream flow conditions at and

above which the designated uses are presumed to exist and applicable

numeric water quality criteria must be met in order for those uses to

be attained. The underlying concept is that these low flow events are a

part of the dynamic hydrologic character of all flowing water bodies.

Low flow conditions present special challenges to the integrity of the

aquatic community. Even under these low flow conditions, however, the

long-term beneficial use could be maintained unless toxic conditions

stress the aquatic community beyond its ability to tolerate and

recover.

In practice, stream design flows serve several purposes in addition

to defining the minimum stream flows below which numeric water quality

criteria do not apply. Many States and Tribes have used the stream

design flows, or fractions thereof, to define the amount of stream flow

that can be assumed to always be available to dilute effluent. Under

rapid and complete mixing conditions, the entire stream design flow is

used as the basis for determining permit limits. That is, no mixing

zone is necessary. Under slow or incomplete mixing conditions, where a

mixing zone is necessary, fractions of stream design flow are used to

calculate assimilative capacity on which permit limits can be based; in

other words, to crudely define the mixing zone. Often this default

approach is used by regulatory agencies in response to limited

resources, lack of site-specific information and the time pressures of

permit reissuance. This default approach to defining the mixing zone

is, in EPA\'s view, acceptable as long as the mixing of the effluent in

the receiving water occurs away from critical areas and the amount of

dilution provided is conservative for a broad range of possible

effluent/receiving water dilution scenarios. However, where a complete

mixing assumption does not hold true, such as where an effluent plume

does not disperse quickly, and too much of the receiving water is

allocated for dilution, this default assumption approach will not

ensure attainment of water quality standards because numeric water

quality criteria will be exceeded in a larger area than anticipated

(outside the regulatory mixing zone). The default use of fractions of

stream design flows instead of more exacting mixing zone determinations

is not always appropriate. In some instances, the effluent plume may

never fully mix with the specified amount of receiving water, resulting

in plumes where criteria are exceeded extending far beyond what may be

considered protective of designated uses or allowed under standards.

EPA has recommended that site-specific information on the mixing

characteristics of a discharge be collected to verify the level of

protection assumed to be provided to a water body using default mixing

zone provisions.

EPA believes it is important for individual States and Tribes to

make consistent dilution allowance decisions from one site to the next.

Requiring States and Tribes, as part of their water quality standards,

to specify how dilution allowances under complete and incomplete mix

situations will be established may be an appropriate way to ensure

consistent decision-making.

To best define dilution allowances for implementing water quality

standards, it is useful to define both stream design flows and effluent

design flows. In particular, a distinction should be made between the

stream design flows to be used for different ambient water quality

criteria (e.g., aquatic life acute, aquatic life chronic, human health

carcinogen). In addition, effluent design flows may vary in some cases

based upon seasonal changes or production cycles. Stream design flows

may be applied as a maximum dilution allowance or adjusted in

individual cases based on

\[\[Page 36793\]\]

any stream-specific or pollutant-specific considerations. Stream design

flows, if they are used, must correspond to the duration and frequency

components of the ambient water quality criteria contained in the State

or Tribal water quality standards. Currently, States and Tribes must

justify the scientific validity of their stream design flow policies

where they differ from EPA\'s recommendations. States and Tribes may

also establish specific guidelines for restricting dilution allowances

in individual cases (e.g., States and Tribes may adopt special

restrictions on dilution allowances for human health criteria where a

discharge is within 2 miles of a drinking water intake).

EPA\'s Great Lakes Guidance and its Technical Support Document for

Water Quality-Based Toxics Control identify acute and chronic stream

design flows to be utilized in drafting permit limits. The Guidance

establishes a 7Q10 or 4-day, 3-year biologically-based stream design

flow for implementation of the aquatic life criterion continuous

concentration (chronic criteria); a 1Q10 for the implementation of the

aquatic life criterion maximum concentration (acute criteria); harmonic

mean flow for implementation of human health criteria; and a 90Q10 for

the implementation of wildlife criteria.

In cases where complete and rapid mixing of effluent with receiving

water does not occur, site-specific mixing determinations must be made.

Although the selection of fractions of stream design flows for the

assignment of available dilution for point source discharges does

affect the size of the regulatory mixing zone, such default assignments

are not hydrologically linked to the actual behavior of the effluent

plume in the receiving water, may not protect swimming and drifting

organisms or sessile or benthic organisms and are not equivalent to a

mixing analysis. There may be other instances where the reliance on a

fixed percentage of flow or cross-sectional area of the receiving

stream in lieu of an actual mixing analysis may not reflect the mixing

behavior of an effluent. In some high dilution situations, there may be

more rapid dilution occurring than is assumed in dilution calculations.

If complete and instantaneous mixing actually occurs, using less

than 100% of the design flow can be a means of accounting for

situations where the actual assimilative capacity of the water body is

unknown. States and Tribes typically determine water body assimilative

capacity based on ambient background concentration of a pollutant, when

data on such concentrations is available. The assimilative capacity is

the difference between the background level of a pollutant and the

highest level that would comply with the water quality criterion. Where

information on all sources of a given contaminant to a specific water

body is incomplete, or where the State or Tribe wishes to reserve

assimilative capacity for the future, States and Tribes should allocate

less than 100% of the assimilative capacity of that water body at

design flow by utilizing less than 100% of the design flow for

dilution. EPA is interested in comment addressing the use of these

stream design flows or fractions of stream design flows in setting

mixing zones and in reserving assimilative capacity in a water body.

The Great Lakes Guidance allows States and Tribes to use default

assumptions for available dilution in the absence of site-specific

mixing data. The default dilution assumption for open waters (e.g.,

lakes) provides for ten-to-one dilution. The Guidance also allows for a

demonstration to determine actual mixing zone water quality, size,

placement and behavior. Under the Guidance, for open waters, in no case

can mixing zone size exceed that area in which discharge-induced mixing

occurs. As a default, the Guidance restricts the mixing zone for

protection of aquatic life from acute effects (i.e., the dilution

allowed in calculating limits based on an acute aquatic life criterion

or CMC) to 2 parts receiving water to 1 part effluent, at water body

design flow or volume.

As a default for implementing criteria for the protection of

aquatic life from chronic effects (CCC) in flowing waters (e.g., rivers

and streams), the Great Lakes Guidance allows States and Tribes to use

up to 25% of the design flow for dilution. If a site-specific mixing

analysis is performed, a larger mixing zone may be established. Mixing

zones for acute aquatic life criteria in flowing waters are limited to

the final acute value or FAV (2 x the acute criterion) just as in open

waters. EPA is interested in comment on whether this FAV default

\`\`cap\'\' approach is appropriate for waters outside the Great Lakes

Basin.

As stated above, the Great Lakes Guidance allows increases above

the default mixing zone allowances when site-specific mixing zone

analyses are conducted. These demonstrations compile data on the mixing

behavior of the effluent at a particular site (e.g., the size, shape

and location of the mixing zone). The Guidance also required that

mixing zones maintain existing and designated uses and comply with

narrative water quality criteria (e.g., \`\`free froms\'\').

The Great Lakes Guidance also specifies that mixing zones may not

jeopardize the existence of threatened or endangered species or their

critical habitat.

EPA advocates the watershed approach to water quality protection.

For the water quality standards program, the emphasis has been toward

refinement of designated uses and incorporation of new and emerging

sophisticated and integrated analytical tools as a means to better

characterize the ecological condition of water resources and more

effectively protect designated uses (see section I(A) \`\`General
Purpose

and Vision\'\' of this document). The development and implementation of

mixing zone policies by States and Tribes constitutes risk management

at the sub-watershed level. EPA has consistently emphasized the need to

ensure that State and Tribal mixing zone provisions protect the

designated uses of receiving waters. Site-specific data collected

through a mixing zone analysis will ensure that designated uses will be

protected the loss of ecological integrity from the discharge of

effluents will be prevented. An emphasis on the protection of

designated uses and maintenance of ecological integrity is essential to

the watershed approach. The watershed approach requires increased site-

specific information on local aquatic systems and an assessment of the

impact of all discharges to local ecosystems. The watershed approach

also depends upon the meaningful involvement of local communities in

risk management decision-making. Explicit, clear implementation

policies provide the public with the information necessary to

understand decisions being made by regulators and the impact of those

decisions on local resources.

Request for Comments on Mixing Zone Policies and Implementation

Procedures

EPA requests comment on the following questions:

1\. Should the regulation be changed to expressly require States and

Tribes to include a statement in their water quality standards

indicating whether mixing zones are allowed?

2\. Should the regulation be changed to expressly require States and

Tribes to specify procedures by which mixing zone decisions for

individual discharges would be made?

3\. Should the regulation be modified to identify the minimum

requirements or elements for State and Tribal mixing zone policies

(including size, location, and methodologies)?

\[\[Page 36794\]\]

4\. Consistent with current EPA policy, should the regulation

explicitly require narrative criteria to apply in mixing zones?

5\. Should the regulation require States and Tribes to identify in

their mixing zone provisions what minimum water quality conditions are

required within mixing zones?

6\. Are there any circumstances, types of pollutants or water body

types (e.g., wet weather discharges) where mixing zones should be

restricted or prohibited?

7\. Should mixing zones for bioaccumulative pollutants be

prohibited? If so, under what circumstances? Should such prohibitions

be addressed on a water body- or basin-specific basis? Should EPA allow

exceptions to any such prohibitions?

8\. Should the regulation require States and Tribes to specify

procedures and decision criteria for evaluating complete and incomplete

mixing?

9\. Should the regulation require different mixing zone/dilution

procedures for complete and incompletely mixed situations?

10\. Should an assumption of rapid and complete mixing within State

and Tribal implementation procedures be prohibited except where a

defensible technical rationale is included in each site-specific

determination?

11\. Should the regulation explicitly allow the use of default

mixing zone assumptions based on fractions of stream design flow in the

absence of site-specific data?

12\. Should the regulation be clarified, consistent with current EPA

policy, to require States and Tribes to identify the water body design

flows or volumes upon which their water quality standards are based?

F. Wetlands as Waters of the United States

The current water quality standards regulation contains no

definition of \`\`waters of the United States,\'\' although this term is

used in the definition of \`\`water quality standards.\'\' The phrase

\`\`waters of the United States\'\' has been defined elsewhere in
Federal

regulations, including regulations governing the National Pollutant

Discharge Elimination System (NPDES). That definition at 40 CFR 122.2

includes wetlands whose use, degradation or destruction could affect

interstate commerce and wetlands adjacent to other waters of the U.S.

However, because this definition does not appear in 40 CFR 131, some

have questioned whether Part 131 applies to wetlands. EPA\'s position is

that the Part 131 regulations do apply to wetlands. EPA is considering

including the definition for \`\`waters of the United States\'\' under
the

standards regulation as well, or, at a minimum, cross-referencing the

definition at 40 CFR 122.2 as a means of clarifying that the existing

regulation applies to wetlands that fall within the definition of

waters of the United States. Currently, EPA plans no review or revision

of the existing definition of \`\`waters of the United States\'\' as
part

of any revision of the water quality standards regulation. Therefore,

under the ANPRM, EPA is interested in comment limited to whether the

existing definition should be included within the standards regulation

in some form.

EPA believes that some States or Tribes may not be providing the

same protection to wetlands that they provide to other surface waters,

including designation of attainable uses consistent with the CWA and

assignment of protective water quality criteria. Therefore, EPA wishes

to emphasize that wetlands require the same protection under water

quality standards as other waters of the U.S. Section 303 of the CWA

requires the protection of all \`\`waters of the U.S.\'\' under
standards.

Addition of the definition of \`\`waters of the U.S.\'\' under a
revision

of the regulations would not constitute an expansion of authority or

application, but merely a clarification of those requirements already

contained within the CWA. Treatment of jurisdictional issues would not

be affected by such a revision, including treatment of waters

constructed as waste treatment systems (e.g., wetlands constructed for

wastewater treatment). Notwithstanding protection of wetlands under

other provisions of the CWA (e.g., Section 404), Section 303 clearly

establishes a baseline level of protection applicable to all waters.

Further, it is this treatment under water quality standards which

provides for protection of wetlands as applied under Section 404.

Necessary components of water quality standards for wetlands are

designated uses and criteria, as defined in 40 CFR 131.6. EPA

recognizes that uses and criteria should reflect the unique physical,

chemical and biological characteristics of wetlands. States and Tribes

are encouraged to develop and adopt appropriate classification systems

which provide protection of beneficial uses of wetlands through the

application of physical, chemical and biological criteria. EPA also

recognizes that certain parameters, conditions or even pollutants may

be most appropriately addressed by criteria which specifically reflect

differences between wetlands and other surface waters.

Request for Comments on Wetlands

EPA requests public comment on the following questions:

1\. Should \`\`waters of the United States\'\' be defined in the water

quality standards regulation?

2\. Should EPA provide explicit reference in the regulation to the

applicability of water quality standards to wetlands?

3\. Do the current regulation and existing guidance provide the

necessary regulatory clarity, technical tools, and incentives for

States and Tribes to develop appropriate standards for wetlands?

4\. Are specific programmatic changes needed to facilitate the

development of water quality standards for wetlands?

G. Independent Application Policy

1\. Introduction

Section 101(a) of the Clean Water Act states: \`\`The objective of

this Act is to restore and maintain the chemical, physical, and

biological integrity of the Nation\'s waters.\'\' To this end, States
and

Tribes designate single or multiple uses for their waters including

aquatic life protection. For the purposes of assessing the extent to

which aquatic life is protected and whether actions to protect aquatic

life are needed, the CWA requires that States and Tribes adopt water

quality criteria necessary to support designated uses. For waters where

aquatic life protection is an applicable designated use, the extension

of the CWA requires States and Tribes to adopt criteria protective of

aquatic life. Taken together, chemical, physical, and biological

integrity define the overall ecological integrity of an aquatic

ecosystem. Over the years, EPA, States and Tribes have developed

various tools to assess the extent to which water quality attains this

objective. These tools have been developed to build on and support the

capabilities of each other and provide a comprehensive set of elements

necessary for implementing water quality standards and achieving the

objective of the CWA. EPA policy and guidance recommends that States

and Tribes use chemical-specific, toxicity, and biological criteria to

monitor and protect designated uses. In 1991, EPA established its

policy on independent application (U.S. EPA, transmittal memorandum of

final policy on biological assessment and criteria from Tudor Davies to

Regions, June 19, 1991). EPA\'s independent application policy speaks to

how assessments based

\[\[Page 36795\]\]

on these three kinds of criteria are to be integrated into all forms of

water quality management decision-making. EPA\'s independent application

policy and the ensuing discussion here address the issue of how the

three different kinds of assessments are interpreted only in the

context of protection of aquatic life and aquatic life uses and not in

the context of protection of human health or wildlife.

With the advent of different ways of assessing the health of

aquatic systems comes the possibility of conflicting results. To

address such conflicts, EPA developed the policy of independent

application. Independent application states that where different types

of monitoring data are available for assessment of whether a water body

is attaining aquatic life uses or for identifying the potential of

pollution sources to cause or contribute to non attainment of aquatic

life uses, any one assessment is sufficient to identify an existing or

potential impact/impairment, and no one assessment can be used to

override a finding of existing or potential impact or impairment based

on another assessment. The independent application policy takes into

account that each assessment provides unique insights into the

integrity and health of an aquatic system. In addition, each assessment

approach has differing strengths and limitations, and assesses

different stressors and their effects, or potential effects, on aquatic

systems. For example, while biological assessments can provide

information in determining the cumulative effect of past or current

impacts from multiple stressors, these assessments may be limited in

their ability to predict, and therefore prevent, impacts. While

chemical-specific assessments are useful to evaluate and predict

ecosystem impacts from single pollutants, chemical-specific methods are

unable to assess the combined interactions of pollutants (e.g.,

additivity). Similar to biological assessments, toxicity testing

provides a means of evaluating the aggregate toxic effects of

pollutants, and like chemical assessments, can also be used when

testing effluent to predict single chemical impacts. One of the

limitations of toxicity testing, however, is that the identification of

pollutants causing toxicity is not always possible or cost-effective.

Each of these three assessment approaches relies on different kinds of

water quality data, measures different endpoints and, in practice, will

be interpreted in the context of implementing a water quality

management program that includes assessment and pollution control.

EPA\'s policy on independent application is based on the premise that

any valid, representative data indicating an actual or projected water

quality impairment must not be ignored when determining the appropriate

action to be taken. Independent application recognizes the strengths

and limitations of all three assessment approaches.

The next three sections briefly describe three assessment

approaches (biological, toxicological and chemical) one could likely be

evaluating when using independent application. Those three sections are

then followed by two parallel discussions on different uses of water

quality data. One use relates to the NPDES permits program to determine

whether a permit must contain water quality-based chemical or toxicity

limits, and what those numeric limits should be. The other relates to

the use of such data to evaluate the quality, or condition, of waters

under the CWA section 305(b) and 303(d) programs. At the core of both

of these contexts is the question \`\`are the present applicable water

quality criteria complete and appropriate for the water body, and how

are we to measure attainment of the present or future criteria that

apply to any water body in question?\'\' Thus, in its most basic sense,

independent application remains a water quality standards question. Any

changes to or clarifications of the policy on independent application

must therefore be considered first under the rubric of water quality

standards and then in the separate contexts of permitting and water

quality evaluation which are based on water quality standards.

States and Tribes routinely determine whether water bodies are

attaining their designated uses and whether existing pollution controls

adequately protect those uses. Some States and Tribes have recommended

to EPA that it modify the independent application policy. Currently,

EPA\'s policy of independent application is the same for both NPDES

permitting and water quality assessment programs. However, EPA

recognizes that each of the programs has somewhat different data needs

and attributes. Therefore, today\'s notice separates the two distinct

uses of independent application to better focus the discussion.

a\. Biological Assessments. Biological assessments are based on

quantifying differences between expected biological community

attributes such as structure, function and condition (known as a

reference condition) and the biological community attributes found at a

specific site being evaluated. The extent to which the community at the

site deviates from the reference conditions is indicative of the degree

of impairment at the specific site. The strength of biological

assessments is their ability to provide a direct measure of the health

of aquatic ecosystems. Biological assessments are also able to detect

non-chemical impacts (e.g., habitat loss, sedimentation, temperature

effects) in addition to chemical toxicity problems.

States and Tribes that use biological assessments, use them

primarily to evaluate the ecological condition of water bodies and to

determine whether a water body is healthy, threatened, or impaired

(i.e., aquatic life use attainment decisions). In some instances,

States and Tribes have used biological assessments to establish

monitoring requirements in an NPDES permit, but generally, most use

bioassessments to make non-regulatory, general, water resource

management decisions. Data from a biological assessment can be compared

to a gradient that shows the reference (expected) conditions without

impairment on one end and the worst situation on the other. States and

Tribes generally use the results to determine whether additional

measures are needed to protect the water segment, or determine how

close to attainment an impaired system is. Biological assessments can

also play a role in linking impairment to causative agents. This link

is often not definitive, but can be very useful in helping to identify

the causes and sources of many impairments. Some States and Tribes have

used indicator species or groups to distinguish effects of toxicity

from effects of organic enrichment. For example, one State documented

that a midgefly larvae is found to be predominant in areas contaminated

by electroplating or metal wastes. Although biological assessments

cannot be used to predict conditions in a mathematical modeling sense,

over time they can be used to indicate the direction of change, and the

degree of that change, in the condition at a particular site. This

information, where it is based on enough data using relatively

sensitive appropriate metrics, can be very valuable in deciding whether

the current condition is likely to be maintained under similar

conditions in the future, or whether there are early warning signs of

biological impacts giving reason to believe that additional regulatory

actions may be needed to prevent water quality standards impairment.

Regulatory actions that are a response to measured change in biological

condition will tend to be restorative more than preventative (i.e.,

\[\[Page 36796\]\]

once biological impact is measured, by definition, that impact was not

prevented). Although, slight changes that are not sufficient to render

a water in non-attainment of its aquatic life use, can provide early

warning of potentially more significant future changes. In contrast, as

noted above, regulatory actions based on impairment predicted, for

example via a chemical-specific modeling analysis, tend to be

preventative. To the extent that conditions in a water body do change

(e.g., flow), biological assessments do not reveal potential future

impacts under other exposure conditions (e.g., low-flow conditions).

Programmatically, there are concerns regarding quality assurance and

quality control for various biological assessment techniques since they

have yet to be promulgated, or standardized, in any EPA programs. This

is mainly due to the site-specific nature of biological assessments.

Implementation of biological criteria is also discussed in section (B)

of this notice.

b\. Toxicological Assessments. Toxicological assessments are

conducted by exposing aquatic organisms to effluent or ambient water

samples or sediment samples in a laboratory and determining the effects

on the exposed organisms. Because toxicity assessments evaluate the

overall effects of the entire suite of constituents in a sample, they

are ideal for identifying interactions between chemicals that can alter

the expected effects of individual chemicals on exposed organisms.

Toxicity assessments also capture the toxic effects of chemical

compounds not commonly monitored for or for which chemical-specific

criteria are lacking. In addition, because it can be manipulated in the

laboratory, toxicity testing can predict the likelihood of ecological

impacts before they occur. This allows safeguards to be put into place

before an actual ecological impact occurs.

Toxicity assessments are usually limited by the variety of species

that can be cultured in the laboratory. While numerous test species can

be used to evaluate the toxicity of individual samples, typically only

two or three species are used for such tests. By comparison, eight

different families are required to develop chemical-specific criteria.

For some toxicants, the broader sensitivity range provided by testing

eight different families is particularly important, for example, where

the mode of toxicity action is specific (e.g., pesticides). Identifying

the cause of toxicity can, in some situations, be a difficult,

expensive, and lengthy process. Another consideration is that toxicity

testing does not detect habitat perturbations which can greatly limit a

water resources aquatic life use. Finally, toxicity assessments are

only valid for as long as all the sample testing conditions remain the

same. Ambient conditions affecting toxicity may change over time

necessitating additional testing.

c\. Chemical Assessments. Chemical assessments measure individual

chemical constituents (e.g., copper, lead) or chemical conditions

(e.g., pH, temperature, hardness, organic content) in a medium.

Chemical assessments may be performed on effluent or ambient water

samples or sediment samples. Chemical analyses are usually simpler to

conduct and generally less expensive than toxicity assessments or

bioassessments, particularly if there are only a few chemicals of

concern, but the information from these tests may provide limited

insight into the ecological condition of the water body. If information

is available on pollutant persistence and degradation, modeling can be

used to predict pollutant fate and transport under a variety of

exposure scenarios. Further, chemical-specific assessments are ideal

for predicting the likelihood of ecological impacts where they may not

yet have occurred either because a proposed activity affecting water

quality has not been implemented or critical exposure conditions have

not yet been experienced by the aquatic community. For these reasons,

regulatory actions based on chemical-specific assessment can be

preventative as well as restorative.

Basing regulatory and management decisions on chemical assessment

of water quality is an important and proven aspect of water quality

assessment and protection. However, as an indirect measure of aquatic

health, one of the principal limitations to chemical assessments is

dependence upon chemical-specific benchmarks (such as chemical water

quality criteria) for determining whether water quality is suitable or

unsuitable for attaining and maintaining aquatic life uses. As noted

elsewhere in this notice, stressors other than specific chemicals in a

water body are often a significant or even predominant cause of

nonattainment of aquatic life uses. EPA\'s current thinking is that

complete reliance on chemical-specific assessments of water quality is

too narrow of a focus and fails to provide information on other

important ecosystem stressors. In addition, as noted elsewhere in this

notice, there are currently water quality criteria for the protection

of aquatic life for 31 chemicals. There are tens of thousands of

chemicals discharged into surface waters. (Note, however, that the

chemicals for which there are criteria tend to be the most frequently

discharged). Thus there is the added problem of too few criteria and

too many chemicals, making it inappropriate to rely exclusively on the

chemical-specific approach. Another substantial limitation of chemical-

specific benchmarks is that for a given site, the benchmarks that are

used, may not be the best that are available to reflect the level of

protection applicable at the site. For example, site-specific aquatic

life criteria are generally different (higher or lower) than the

national recommendations for the same chemical. And yet absent site-

specific criteria, the national recommendations are often used.

2\. Independent Application and Water Quality Assessments

a\. Independent Application. States and Tribes often collect or have

access to monitoring data that measure the concentration of specific

chemicals in an effluent or water body, the level of toxicity present

in ambient water or discharges to a water body and/or the biological

community composition within a water body. These data are then

interpreted by comparing them to reference conditions or criteria to

determine whether or not aquatic life uses are attained. EPA\'s 1991

policy on independent application was explicit about the use of

independent application in water quality programs: \`\`This policy,

therefore, states that appropriate action should be taken when any one

of the three types of assessment determines that the standard is not

attained. States and Tribes are encouraged to implement and integrate

all three approaches into their water quality programs and apply them

in combination or independently as site-specific conditions and

assessment objectives dictate.\'\' In implementing this policy, EPA

recommends that data from the three assessment approaches be applied

independently in water quality programs since each method provides

unique and distinct information on the characteristics of the water

body. In other words, EPA recommends that differences in assessment

results be resolved in one of two ways: either presume an adverse

impact when any one source of data indicates an adverse impact, or

reevaluate the complete data set and modify the applicable criteria to

account for the new site-specific information. Given EPA\'s mission to

protect the environment and absent definitive data to demonstrate that

an assessment is in error or otherwise biased, EPA presumes

\[\[Page 36797\]\]

where an assessment indicates impairment, that assessment is valid.

In the context of applying the independent application policy to

the assessment of water bodies, there are two distinct CWA provisions

to consider: (1) section 305(b), which requires States and Tribes to

report to EPA and EPA to report to Congress a description of the

quality of the Nation\'s waters; and (2) section 303(d), which relates

to identification of waters where technology-based limitations and

other required controls are not stringent enough to ensure that

applicable water quality standards will be attained and maintained.

With respect to the section 305(b) Report, the CWA broadly calls for

States and Tribes to assess water quality conditions in a biennial

report. EPA transmits these reports to Congress, together with an

analysis of the reports describing water quality conditions. Because

these are water quality assessment reports that States and Tribes

submit to EPA, and not specific regulatory decisions, there may be

sufficient flexibility in the interpretation of data to allow a more

integrated approach to evaluating limitations and inconsistencies in

the interpretation of data produced under various approaches. For

example, direct assessments of the condition of the waters (e.g.,

biological assessment) could be weighted more heavily than indirect

measurements (e.g., chemical and toxicity).

With respect to section 303(d), the CWA and EPA\'s implementing

regulations require States and Tribes to identify those waters for

which technology-based limitations and other required controls are not

stringent enough to achieve water quality standards applicable to such

waters. See 303(d)(1)(A), 40 CFR 130.7(b)(1). When identifying waters

pursuant to 303(d), the methods used to determine non-attainment of

standards for water quality reporting under 305(b) should also be used.

However, water bodies are eliminated from 303(d) list consideration if

technology-based controls or other required Federal, State, Tribal or

local requirements will result in the attainment of applicable water

quality standards. TMDLS developed to secure restoration of designated

uses are largely dependent upon chemical criteria and assessment to

define acceptable pollutant loadings.

The question arises as to whether States and Tribes have the

flexibility to exclude a water body from 305(b) reports and 303(d),

i.e., conclude that the designated use was protected, even in the face

of data indicating one or more excursions of the applicable chemical-

specific water quality criteria. EPA would like to consider possible

mechanisms under the existing CWA and the legal theories supporting

them to address these questions.

As with determining the need for regulatory controls (permit

limits), similar data evaluation issues face States, Tribes and EPA in

performing water body assessments for purposes of sections 303(d) and

305(b) of the CWA. With respect to such assessments, EPA\'s goals for

States and Tribes are twofold: (1) to encourage the use of chemical,

toxicological, physical and biological data in making water body

assessments; and, (2) to ensure that the data are interpreted and

reported in a consistent and scientifically defensible manner so that

documents such as the 305(b) report to Congress provide valid and

useful information on the status of the Nation\'s waters as a whole,

irrespective of State or Tribal boundaries.

EPA recognizes that there may be instances where these goals appear

to be in conflict. It is possible that as States and Tribes implement

biological assessment programs, they may identify new areas of impact

that were previously undetected using other assessment techniques and

that this may lead to a reluctance on the part of States and Tribes to

develop the expertise necessary to conduct biological assessments.

Although this tendency is contrary to the goals and objectives of the

CWA, the fact is that addressing new and previously unaddressed threats

to surface water quality places additional strain on already limited

State and Tribal resources. Some also feel that adherence to a strict

independent application policy for assessment purposes discourages the

use of more data than minimally needed to make an aquatic life use

assessment. In most cases, the minimal amount of data would be a

chemical grab sample for a few water quality characteristics such as

temperature, pH, BOD, or dissolved oxygen. Collecting minimal data for

assessment reporting is much easier and less resource intensive for

States and Tribes that are required to increase their reporting

coverage, and these States and Tribes would not have to deal with

differing interpretation of assessment results.

However, EPA believes that placement of waters on section 303(d)

and section 305(b) lists should be based on broad thorough assessment

data, not on limited and narrow data. The former will help ensure that

targeted water quality controls and management actions are appropriate

and will result in water quality standards attainment; the latter can

result in significant outlays of State and Tribal resources targeted on

waters where water quality problems are not well understood. EPA is

considering how best to obtain accurate, high-quality assessment data

and how to reconcile differences between assessments conducted using

different techniques in a manner that fosters consistency and remains

scientifically defensible.

b\. Alternatives to Independent Application.

There is considerable sentiment among various stakeholder groups

that there is a need to better incorporate more comprehensive data,

particularly biological data, into the water quality assessment

framework described above and that doing so will facilitate collection

and use of more integrated and insightful water quality data. EPA

shares this view. Some have used the term \`\`weight-of-evidence\'\' to

describe an alternative to the present EPA policy of independent

application that could facilitate integration of chemical, physical,

toxicological and biological data into the assessment program. However,

EPA recognizes that individuals\' views about the meaning of the term

\`\`weight of evidence\'\' vary considerably and this variation should
be

addressed. The term \`\`weight-of-evidence\'\' has been interpreted by
some

to mean that one approach to assessment, e.g., biological, could

routinely be used to override conclusions drawn using another

assessment technique, e.g., chemical. EPA believes that approach is

hierarchical, not a weight-of-evidence approach. EPA\'s position is that

each approach, chemical, toxicological, physical and biological has

inherent strengths and limitations and that all valid water quality

assessment data generated under any of these approaches should be used

in assessing the health of aquatic ecosystems, in ways that adequately

take into account the strengths and limitations of each approach.

EPA\'s current thinking is that as forms of water quality assessment

data have become broader (chemical, physical, biological and

toxicological), and as the amount of such data increases, the water

quality standards and assessment programs need to facilitate continued

collection and use of such data, and that doing so will lead to more

thorough water quality assessments, more insightful water quality

criteria, and better descriptions of aquatic life designated uses. EPA

would not support an approach that could lead to collecting fewer and

narrower water quality data by States, Tribes and dischargers. On the

contrary,

\[\[Page 36798\]\]

EPA\'s current thinking is that to employ a weight-of-evidence approach,

a State or Tribe (or EPA) would need to have a comprehensive set of

water quality data to evaluate the chemical, physical, toxicological

and biological conditions in a water and to conduct ecological impact

assessment to determine the precise causes of impacts (chemical,

physical, biological, and toxicological) and how best to address them.

EPA\'s current thinking is that the most appropriate context for using a

weight-of-evidence approach would be in establishing criteria. In

addition, as discussed below, EPA is interested in evaluating the use

of a weight-of-evidence approach for assessment and reporting under

section 305(b) of the CWA. However, once the criteria are established

for a water body, the assessment for purposes of listing under section

303(d) of the CWA and permitting under NPDES, must be based on all

applicable water quality criteria.

EPA\'s 305(b) reporting guidelines interpret the independent

application policy to apply to aquatic life use assessments for State

305(b) reports, not just to permitting for protecting waters due to

reasonable potential to violate water quality standards. This policy

helps protect against dismissing valuable information when evaluating

aquatic life use attainment, particularly in detecting impairment. This

approach is most protective when there is limited data available and

when there is no documentation on the rigor of the assessment. EPA is

concerned that lack of information can provide false confidence about

the health of the nation\'s water bodies. However, EPA is now developing

a comprehensive approach for conducting aquatic life use assessments

which integrates chemical, toxicological, physical and biological data,

and includes consideration of the strengths and limitations of the

assessment methods and the data. This shift toward more integrated

assessments is reflected in EPA\'s most recent guidance to the States

and Tribes on conducting 305(b) assessments, particularly in

determining nonattainment (EPA\'s Guidelines for Preparation of the 1996

State Water Quality Assessments (305(b)) reports, EPA 841 B-95-001) and

is the primary focus of the Office of Water\'s Criteria and Standards

program Plan. The 1996 305(b) guidelines are consistent with the Policy

on Independent Application while incorporating a weight-of-evidence

approach in determining the degree of impairment (partial or

nonsupport). The 1996 guidelines do not allow for a finding of full

support, or attainment, of aquatic life use when there are differences

in assessment results. Under certain circumstances, however, the

guidelines allow for the possibility of a finding of partial support,

even where results of different assessments are not fully consistent.

Generally, in assessing severity of impairment, assessments based on

data with high levels of information, or rigor, should be weighted more

heavily than those based on data with low levels of information, and,

rigorous biological data should be weighted more heavily than other

data types. EPA recommends that the results of biological assessments,

especially those with high levels of information, be the basis for the

overall aquatic life use support (ALUS) determination if the data

indicate impairment. This is because rigorous biological data provide a

direct measure of the status of the aquatic biota and detect the

cumulative impact of multiple stressors on the aquatic community,

including new or previously undetected stressors.

Determining the level of information or rigor for each assessment

is a critical component of the 305(b) guidelines on making an ALUS

determination. The levels of information allow characterization of the

quality and the temporal and spatial coverage of the data States and

Tribes utilize to conduct their use assessments. Levels of information

are identified for assessments based on biological, physical, chemical

and toxicological data. For example, measures of the condition of the

aquatic community using indices incorporating multiple assemblages of

aquatic organisms based on a regional reference approach would rate

higher than a measure of a single organism or single metric or annual

fixed station monitoring for chemical contaminants. Likewise, three

years of bi-monthly fixed station monitoring for chemical contaminants

would rate higher than annual fixed station monitoring for the same

chemicals or a biological measure of a single organism or metric.

Understanding the breadth and robustness of the assessment methods used

in evaluating whether a water body is attaining its designated aquatic

life use is important information for EPA, the States, and the public.

In the future, EPA will be evaluating possible scenarios where a

finding of full support could be justified despite differences in

assessment results. For example, a finding of full support based on

rigorous biological data may be justified despite differences with

chemical specific assessment results depending on the magnitude and

frequency of the chemical exceedances and the applicability of the

chemical benchmark to the site. It will be important for EPA to

carefully evaluate such potential scenarios and to define the adequate

data requirements and level of rigor necessary to support a

determination of full support despite differences in assessment

results. Equally important, EPA will need to carefully consider the

ramifications of such determinations on other parts of its water

program.

Another permutation of the weight-of-evidence approach to aquatic

life use assessment is to establish a hierarchy in which the results of

one method could always override the other methods should there be

difference in assessment results. Most frequently, it has been argued

that biological assessments could always override chemical assessments

in determining whether the designated aquatic life uses are being

attained. Some prefer this approach because a rigorous biological

assessment provides a direct measure of existing ecosystem health and

have expressed concern that the policy of independent application

oversimplifies the relationship among different data sets used to

assess current water quality conditions. Proponents of this approach

contend that biological assessment is an integrated assessment that

incorporates the information that would be provided through either

chemical or toxicological assessments into a single, comprehensive

measure of aquatic ecosystem health. Some advocate the acceptance of

rigorous biological data as the ultimate arbiter of aquatic life use

attainment. They also suggest that, at least with respect to current

aquatic life condition assessments, chemical, toxicological, and

biological assessments are not independent; each measures the same

assessment endpoint, but from different stressors. These proponents say

that biological assessment is the only assessment approach available to

integrate and reflect current effects from chemical, toxicological,

physical, and nonpoint source stressors. Because of this they suggest

that rigorous data based on biological assessments and criteria should

automatically supersede data from other sources when determining

aquatic life use attainment. Some contend that if biological data

demonstrate that biological criteria are attained, then the water body

is attaining its designated use, even if other monitoring data such as

toxicological or chemical data demonstrate an excursion, or potential

for an excursion, above a water quality criterion.

Some also contend that rigorous biological assessments should be

used

\[\[Page 36799\]\]

to supersede assessments based on predicted impacts such as water

quality modeling and wasteload allocations in decision making for

aquatic life use assessments. One concern with this perspective is that

non-rigorous biological assessments could be used in such situations,

though EPA has 305(b) reporting guidance which suggest minimum quality

of biological assessments that could also be used for these situations.

In this guidance, EPA recommends using more than one assemblage (fish

and/or macro invertebrates/and or algae), several index values or

metrics (multiple metrics), an index period for sampling, and

ecoregional or other biogeographic regional calibration.

EPA agrees that rigorous biological assessment based on adequate

site-specific data is a direct assessment of aquatic ecosystem health,

unlike chemical and toxicity assessments. However, biological

assessments are less well suited for use in preventing water quality

impacts and will only reflect impacts once they have occurred. Though

this may be less of a concern in waters with a relatively constant

level of discharge where there has been ongoing biological assessment.

A second objective of water quality assessment under the CWA, beyond

assessing when the aquatic life use is impaired, is assessing when

stressors, if left unchecked, will cause impairment. As discussed

above, the chemical-specific approach is especially strong for use in

identifying and predicting impacts before they happen.

EPA is concerned that the use of a hierarchical approach may ignore

or undermine valuable information, whether that information is

biological, physical, chemical, or toxicological, and not trigger the

appropriate action to address the inconsistency (e.g., evaluation of

existing criteria and development of site-specific criteria).

Therefore, EPA does not support such an approach. EPA has a number of

concerns with any approach wherein data from certain assessment

techniques may be automatically superseded by those from others. A

primary concern is the failure of such a system to make use of all

valuable information. In all cases, criteria, whether chemical-

specific, toxicological, physical or biological, are derived with the

intent of identifying a threshold beyond which unacceptable impacts to

aquatic ecosystems are expected to occur. In most cases, it is expected

that when different assessment techniques (i.e., chemical and

biological) are used for determining attainment of aquatic life uses,

the techniques will yield similar results if all are done rigorously.

In addition, it is expected to be rare for chemical assessments to

indicate nonattainment where biological assessment indicate attainment;

analyses conducted by the State of Ohio confirm this. (See Yoder, C.,

\`\`Answering Some Concerns about Biological Criteria Based on

Experiences in Ohio.\'\'). However, it is also expected that in certain

cases, different assessment techniques will result in different

determinations of aquatic life use attainment due to the fact that each

technique evaluates aquatic life use attainment differently, and some

take into account safety factors for ensuring future attainment while

others focus on the current status of the condition. When different

assessment techniques that are intended to measure similar

environmental endpoints and yield comparable results fail to do so, it

may be an indication that assumptions underlying the criteria are not

valid for a particular site, or that the data were not rigorous.

While in some cases it may be appropriate to weigh one set of data

more heavily than another in making a use attainment determination, in

others it may be preferable to take advantage of such circumstances as

opportunities to validate and cross-check criteria, making adjustments

as indicated by the data. This could result, for example, in an

adjustment to a specific chemical criterion in a particular water if

rigorous biological assessment indicated that such an adjustment is

appropriate. Such information is also useful to EPA in improving

national criteria development methodologies.

Lack of comparability in assessments is also a concern for either a

weight-of-evidence or a hierarchical approach to aquatic life use

assessments. Therefore, it is important that there be a common

understanding between States, Tribes and EPA as to how conflicts in

data interpretation will be resolved in evaluating and reporting water

quality. Developing comparable methods to handle data conflicts will

make comparisons between States and Tribes more useful, such as in

305(b) reports. Without a consistent approach to resolving data

conflicts, assessments of water quality data at the national level

becomes problematic. EPA\'s policy of independent application is one way

of providing a consistent and defensible framework for data evaluation

in order to minimize this problem.

Request for Comments on integration of data in water quality

assessments

EPA is interested in comment on how chemical, physical,

toxicological, and biological assessments can be effectively

incorporated and implemented in State and Tribal water quality

standards programs to achieve the goals of the CWA.

EPA requests comments on the following questions:

1\. How can conflicting interpretations of water quality assessment

data be reconciled in a scientifically defensible manner? Should each

kind of water quality information stand alone as a scientific measure

of current water quality conditions and ecosystem health?

Alternatively, are there situations where one type of data should be

given more weight than another in determining use attainment?

2\. How should States and Tribes evaluate water quality information

generated using chemical, toxicological, physical, and biological

methods when determining use attainment status?

3\. When interpretation of water quality data indicate inconsistent

results, what factors (i.e., data richness), if any, should EPA

consider relevant to determining \`\`appropriate actions\'\'?

4\. Should EPA explicitly address in the water quality standards

regulation the evaluation assessments using chemical, toxicological,

physical and biological assessment methods?

5\. Should an approach be instituted where independent application

may be relaxed for water quality assessment strategies and decisions

when a State or Tribe has established a comprehensive monitoring and

assessment program including biological monitoring and assessment? What

guidelines should be used to evaluate a State or Tribal biological

monitoring and assessment program?

6\. How should the policy of independent application address the

distinction between situations where adequate rigorous data are

available for each assessment technique and situations where available

data for one or more of the assessment techniques are limited in

quantity or quality? Specifically, should the policy be modified to

more explicitly encourage or require, where feasible, additional

monitoring, particularly where limited data are to be used as a basis

for regulatory action?

3\. Independent Application and NPDES Permitting

a\. Independent Application. Clean Water Act section 101(a) states

that \`\`\[t\]he objective of this Act is to restore and maintain the

chemical, physical, and biological integrity of the Nation\'s
waters.\'\'

In the context of implementing water quality-based pollution controls

under the NPDES program, EPA has maintained that independent

\[\[Page 36800\]\]

application of all forms of water quality assessment data (i.e.,

chemical, physical, toxicological and biological) is clearly consistent

with this objective. In addition to restoring impaired surface waters,

water quality-based pollution controls are often implemented to prevent

water quality standards impairment that projections indicate will occur

in the absence of the water quality-based controls. Thus, predictive

assessment tools are necessary and have proven effective in the NPDES

water quality-based program.

An important question in NPDES permitting that EPA\'s policy of

independent application was specifically developed to address is: how

should differences in interpretation of water quality data produced

using different water quality assessment techniques for aquatic life

uses be reconciled? Upon examination of this question, EPA determined

that differences in data interpretation do not necessarily equate to

contradictory results. Different assessment results may be

complementary since the different approaches can measure different

aspects of water quality. For aquatic life uses, all three data types

(chemical, toxicological, and biological) provide useful information

and should be used to protect designated uses. Because the different

types of assessments often focus on different aspects of aquatic

community health and each has different strengths and limitations, it

is possible that any one type of assessment may fail to detect

impairments, or potential impairments of the designated use. For that

reason, EPA\'s current interpretation of the CWA and its implementing

regulations is that all three types of data (chemical, toxicological,

and biological) should be used when evaluating the reasonable potential

for a discharge to cause or contribute to an excursion above a water

quality criterion and, if one approach indicates that water quality is,

or will be, impacted, the results from the other methods could not be

used to refute that finding. Under this approach, where \`\`reasonable

potential\'\' is found, the NPDES permitting authorities must take

appropriate \`\`actions;\'\' that is, implement water quality-based

effluent limits that are derived from and comply with the applicable

water quality criteria. These \`\`actions\'\' may also include
additional

monitoring to determine whether a problem exists, or to derive site-

specific criteria if a particular criterion is found to be inaccurate

for a site. The policy on independent application is presented in

further detail in Chapter 1 of EPA\'s 1991 Technical Support Document

for Water Quality-based Toxics Control (TSD) and in chapter 1 of EPA\'s

Water Quality Standards Handbook\--Second Edition, September 1994

(Handbook) (both documents cited above).

In the Great Lakes Guidance, EPA maintained its policy of

independent application with respect to determining the need for water

quality-based effluent limits, making it an explicit implementation

requirement in the Great Lakes States. The Guidance, in Appendix F,

Procedure 5, section F \`\`Other Applicable Conditions,\'\' states
\`\`When

determining whether WQBELs are necessary, information from chemical-

specific, whole effluent toxicity and biological assessments shall be

considered independently.\'\' (40 CFR Part 132, Appendix F, Procedure 5,

Section F.3.).

In the permitting context, EPA\'s independent application policy

reflects language in sections 301(b)(1)(C) and 303 of the CWA and

permit regulations implementing these statutory provisions at 40 CFR

122.44(d). Pursuant to section 303 of the CWA, States and Tribes adopt

chemical-specific numeric criteria and toxicity criteria as part of

their water quality standards. Section 303(c)(2)(B) of the CWA further

requires States and Tribes to adopt, as part of their water quality

standards, numeric criteria for toxic pollutants for which EPA has

published guidance under section 304(a), and whose discharge or

presence in State or Tribal waters could reasonably be expected to

interfere with the designated uses adopted by the State or Tribe for

those waters. (As discussed elsewhere in this document, all States and

Tribes have narrative water quality criteria as well.)

Section 301(b)(1)(C) of the CWA requires effluent limitations in

NPDES permits that are \`\`necessary to meet water quality standards\'\'
or

necessary to \`\`implement any applicable water quality standard.\'\'

Consistent with this provision, EPA\'s permitting regulations at 40 CFR

122.44(d) require that effluent limits be imposed where the discharge

has the \`\`reasonable potential\'\' to cause or contribute to an
excursion

above water quality criteria and specifically describe how those limits

are to be expressed (e.g., chemical-specific versus WET limits).

Therefore, once a numeric (or narrative) water quality criterion

becomes part of a State\'s or Tribe\'s water quality standards, and a

permitting authority determines that a discharge of a pollutant would

have a reasonable potential to cause or contribute to an excursion

above the applicable numeric or narrative criterion, the regulation

requires that a limit for that pollutant be established as necessary to

meet the water quality criterion. Although the CWA specifies that

permit limits must meet water quality standards, it is the permitting

regulations that specify the factors that must be considered when

determining whether or not there is reasonable potential to cause or

contribute to an excursion above a State or Tribal water quality

standard, and specifically describe how such limits are to be

expressed.

EPA regulations at 40 CFR 122.44(d)(1)(iii)-(v) describe the

conditions under which water quality-based effluent limits for specific

chemicals and for whole effluent toxicity are required in NPDES

permits. While these regulations do not specifically use the term

\`\`independent application,\'\' the concept is expressly laid out.
These

regulations require chemical-specific limits when the permitting

authority determines there is a reasonable potential for the discharge

to cause or contribute to the excursion above the chemical-specific

criterion. Likewise, the regulations require limits for whole effluent

toxicity if the permitting authority determines there is a reasonable

potential for the discharge to cause or contribute to the excursion

above the numeric criterion for toxicity or narrative criterion for

water quality. Except under limited circumstances (where the State or

Tribe lacks a chemical-specific criterion for a pollutant of concern),

these regulations do not allow a permitting authority to forgo one type

of limit, e.g. a chemical limit, where another type of data, e.g.,

toxicity, indicate no toxicity. Instead, the two types of data are

required to be considered independently.

The independent application policy provides a consistent and

coherent protocol for resolving conflicts in interpreting monitoring

data when determining \`\`reasonable potential.\'\' Where such conflicts

exist and cannot be reconciled, independent application directs States

and Tribes to presume that the data that indicate a current or

potential impact are valid and to take appropriate steps to prevent or

remediate the impact. The reconciliation phase allows a State or Tribe

to gather additional or more detailed data prior to taking regulatory

action. Data interpretation conflicts may be best addressed by

identifying the cause of the conflict and recalibrating the models and

criteria to better reflect the newly acquired site-specific

information. However, if the causes of the data interpretation

conflicts cannot be resolved, under independent application, the State

or Tribe must take

\[\[Page 36801\]\]

action based on the data indicating impairment or the reasonable

potential for impairment of the water body.

EPA believes this procedure for addressing conflicting

interpretations of monitoring data is appropriate for a number of

reasons. First, as stated earlier, each of the different assessment

techniques monitors aquatic ecosystem health from a slightly different

perspective. Consequently, it is entirely plausible that only one of

the assessment techniques would detect a real or potential impact.

Second, assuming that the data generated by the different techniques

are of comparable quality and relevance, an indication of a water

quality problem using any of the techniques is sufficient reason to

implement controls. That being the case, EPA believes the independent

application of water quality data in determining when water quality-

based effluent limits are necessary for individual dischargers is

consistent with the CWA.

Reconciliation of data interpretation conflicts allows flexible

evaluation of data. Once a permit application is received from a

discharger, States and Tribes frequently engage in discussions with the

discharger over the quality and representativeness of the data. This

period of data review and evaluation is also an ideal time for

addressing any data interpretation conflicts in order to ensure that

permitting decisions are defensible and the permit limits that are

imposed are necessary to protect designated uses. States and Tribes,

together with permittees, may obtain additional data to verify earlier

data or conduct timely studies to support the development of site-

specific criteria. Ultimately, these site-specific criteria may serve

as the basis for a permit limit, or a decision that it is not necessary

to limit a pollutant in a particular discharge. All of the actions

above are consistent with the independent application policy and the

CWA.

Critics of EPA\'s policy believe either that data from certain types

of water quality assessments have inherently greater value than data

obtained by other means or that, in a sense, data quality and

ecological significance should be averaged, such that if data obtained

from two different assessment methods agree and data from a third

disagree with the other two, the two could \`\`outweigh\'\' the one. In

either case, all of the available data would be considered together,

under the assumption that each assessment technique measures a similar

endpoint. Under such an approach to data evaluation, limits on effluent

toxicity would be appropriate and acceptable as surrogates for

chemical-specific limits. Similarly, biological assessment data that do

not indicate unacceptable levels of impact on the biological community

could serve as the basis for a decision not to include either chemical-

specific or effluent toxicity limits designed to support an aquatic

life use in a facility\'s discharge permit. Proponents of this view

argue that independent application forces them to take inappropriate

regulatory actions when faced with conflicting assessment data. EPA

does not agree in principle with this view.

b\. Alternatives to Independent Application. States, Tribes,

municipalities, and dischargers have expressed concerns that the policy

of independent application results in more protection than is necessary

to attain and maintain aquatic life designated uses. Many express a

preference for an approach which invests data obtained using certain

assessment techniques with greater credibility than those obtained in

other ways. Such an approach, as discussed above, is sometimes referred

to as a weight-of-evidence approach. Under such an alternative

approach, assuming a high level of confidence in all the available

data, one form of data\--usually it is argued biological data\-- would
be

the ultimate arbiter of whether water quality-based effluent limits are

needed in a discharger\'s permit. To determine, for example, whether a

water quality-based effluent limit is needed for a particular chemical

pollutant, the risk of adverse impact on the aquatic community would be

determined based on all of the available data relying more heavily on

high quality, thorough biological data and on the judgment of the

individual conducting the evaluation. Several States and members of the

regulated community have advanced this approach as preferable to EPA\'s

independent application policy, arguing that such flexibility to

exercise judgment is appropriate.

EPA\'s current thinking is that it should not promote an alternative

approach to making \`\`reasonable potential\'\' decisions that places

greater emphasis on biological data. Instead, EPA\'s current thinking is

that such an evaluation of water quality and ecosystem health to

determine the appropriate and applicable criteria against which

discharges will be evaluated is most appropriately done during the

setting of the applicable criteria for a water body. In that arena, it

may be feasible to use biological assessment as a basis for determining

the appropriate criteria for a given water body. However, once the

criteria are set, EPA believes that the current regulation requires

\`\`reasonable potential\'\' evaluations against all the applicable

criteria, and that the policy of independent application in this

context is appropriate.

If biological data indicate that designated uses are being attained

in spite of projected or actual chemical-specific criteria exceedances,

then additional site-specific analysis should be done to ensure that

controls are developed that are necessary to adequately protect the

water body from use impairment. Site-specific approaches could include

mixing zone studies, more refined water quality modeling to support

wasteload allocation, or the development of site-specific criteria. In

any case, chemical-specific and toxicity criteria are proven and

necessary bases of water quality-based effluent limits. In
\`\`reasonable

potential\'\' analysis, chemical-specific monitoring is usually focused

on pollutant concentrations in the effluent and the projected ambient

result of those concentrations being discharged. Thus, this type of

analysis commonly yields projected rather than measured water quality

impacts. Where biological impact is not detected using biological

assessment methods, it is possible that impairment that is projected

and plausible, may simply have not yet occurred. However, where

discharges to a stream have been relatively constant over time and

there has been ongoing biological assessment, this would be less of a

concern. EPA\'s view is that it would be inappropriate to ignore

projected impairment simply because the impairment has not yet been

observed in the environment.

An additional argument in favor of retaining the independent

application policy for \`\`reasonable potential\'\' determinations has
to

do with the suitability of certain types of data and the unsuitability

of others for certain applications within the water pollution control

program. For example, biological data are not amenable in the same way

as chemical-specific data for use in waste load allocations, load

allocations, total maximum daily load calculations or antidegradation

reviews. An approach that would allow biological data to negate a

finding of \`\`reasonable potential\'\' would suggest possible site-

specific inadequacies of particular criteria without providing the

information needed to determine definitively whether or not the

criteria are appropriate or what any alternative criteria should be. As

a consequence, a void would be created in the implementation of State

or Tribal water quality standards which would render them unable to

perform all of their

\[\[Page 36802\]\]

intended functions. Proponents of independent application contend that

instead of discarding data and invalidating criteria where conflicting

interpretations exist, an effort should be made to determine why the

interpretations conflict and to refine the applicable criteria to

better reflect the conditions found at the site. Taking this step would

ensure that, over time, a full suite of appropriate criteria would be

developed for every site and that all appropriate and necessary

pollution controls are implemented. In addition, such an approach is

consistent with the CWA. Some States and Tribes may be concerned,

however, that revising water quality standards, especially where such

revision is to deal with a single permitting decision, may be so

resource intensive that it is not a realistic option.

As discussed above, if numeric water quality criteria exist and are

applicable to a water body, permits for dischargers to the water body

must ensure that those criteria are met under section 301(b)(1)(C) and

the implementing regulations at 40 CFR 122.44(d). On occasion, States,

Tribes and dischargers have asserted that biological and toxicity data

from specific waters conflict with chemical data. EPA\'s current

thinking is that instances of clear disagreement between biological and

toxicity data and chemical data are infrequent. Based on this belief,

EPA would not support a radical shift away from chemical criteria and

limits or toxicity criteria and limits. Those tools are simply too

important as proven tools for assessing potential impacts to surface

waters and improving water quality. EPA\'s current thinking also

suggests that it is important for there to be flexibility to resolve

instances of disagreement between different forms of data and that

perhaps mechanisms for such flexibility can be clarified or improved.

EPA\'s current thinking is that through collection of broader and more

thorough water quality data, EPA, States and Tribes will be able to

develop more complete profiles of water body conditions and stressors

and that through such evaluation the \`\`necessary actions\'\' (e.g.,
water

quality-based effluent limits for one or more pollutants, listing of

the water body as not attaining its aquatic life designated use, or

best management practices to address nonpoint sources of pollution) to

improve water quality in a given water will become more obvious.

Disagreement between biological, toxicity and chemical data for the

same water is cited by some States and dischargers as a potential

situation in which independent application would force unnecessary and

burdensome requirements on dischargers. Those opposed to independent

application of criteria would like to see States and Tribes given

greater latitude to determine when limits based on a given criterion

are necessary. They suggest that this could be achieved if States and

Tribes were to include, in the chemical-specific criteria or toxicity

criteria portions of their water quality standards, statements

explaining circumstances under which the otherwise applicable criteria

would not apply at a particular site or would have to undergo some

review and revision, while assuring the designated use of the water

body would be maintained. Such circumstances could include where the

form of the pollutant in the effluent or receiving water is not the

form addressed by the chemical criterion in the State or Tribe\'s

standards; or, where a substantial amount of biological and or toxicity

data indicate that discharges of the pollutant at levels that would

exceed the chemical criteria are not causing the aquatic life use in a

particular water body or segment of the water to be impaired. If these

conditions could be met, permitting authorities would have the

flexibility to determine that a numeric water quality-based effluent

limit for the pollutant in question is not required, or that an

alternate limit should apply. This type of flexibility, to rely on

biological evaluations in the criteria setting phase, where data are

sufficient to support such flexibility, could be a strong incentive for

States and Tribes to develop stronger biological criteria and

assessment programs including monitoring reference areas and complete

chemical and toxicity monitoring programs, including site-specific data

on most sensitive species to chemical(s) for which flexibility is being

sought. EPA approval of water quality standards implementing such an

option requires acceptance of an interpretation that sections

301(b)(1)(C) and 303(c)(2)(B) of the CWA allow States and Tribes to

identify, within their water quality standards, conditions or

circumstances which would render specific numeric criteria not

applicable to certain waters in specific instances, or alternatively in

need of refinement.

EPA has significant technical questions about how such an option

could be implemented within the context of a State\'s or Tribe\'s water

quality standards. EPA is especially interested in detailed technical

comments describing how such an option would be included in a State\'s

or Tribe\'s water quality standards, how such an option would ensure

protection of designated uses in water bodies where criteria are deemed

not applicable. In addition, EPA is soliciting comment on specific

procedures that could be used by a State or Tribe to arrive at a

decision that a criterion is not applicable at a specific site. In

particular, EPA is interested in technical evaluations of what types of

data would be necessary to support such a decision, the quantity and

quality of the data and how the data would be evaluated. Finally, EPA

seeks detailed technical comments indicating how other elements of the

water quality standards program would function in situations where

chemical or toxicological water quality criteria were adjusted based on

biological assessments. For example, if a State or Tribe were to employ

the option discussed above, it is not apparent how critical water

quality program elements such as determining the need for permit limits

or whether or not a new discharge could be allowed to a stream segment

could occur absent chemical-specific or toxicity-based criteria

applicable to the water body. To be workable, this option may need to

be paired with a scientifically defensible mechanism for making

decisions about activities such as permit limits and load increases.

Since chemical criteria and chemical-specific interpretations of

narrative criteria currently are the principal benchmark used for these

functions, would pursuing the option discussed above be workable, or

would it introduce a level of complexity into State and Tribal water

quality standards that could result in slowed or suspended water

pollution control programs, and expose aquatic ecosystems to greater

risk because of the lack of an identified threshold of impact?

EPA\'s current thinking is that significant flexibility already

exists within the current regulatory framework to account for available

biological and toxicity data. For example, numeric criteria, once

adopted, may be modified to better reflect conditions at a specific

site. Bioassessment and toxicity data can play a valuable role in

identifying sites where conditions differ sufficiently from those

assumed in the calculation of the national or State or Tribe-wide

criteria to warrant site-specific modification of the criteria.

Bioassessment and toxicity data can also provide useful information in

identifying instances where a given constituent in an effluent is

toxicologically distinct from a similar substance for which a criterion

is available, indicating the need for a separate criterion for the

constituent in

\[\[Page 36803\]\]

question. Establishing site-specific criteria would provide relief

similar to that contemplated in the option proposed above.

Lastly, public participation is a basic tenet of the water quality

standards development process. Public participation is also sought in

the context of issuing NPDES permits. During standards development,

public input is sought to assist the regulatory agency in identifying

the appropriate water quality goals for the waters under the

jurisdiction of a State or Tribe. During NPDES permit issuance, public

input is again sought to verify that the permit proposed to be issued

is consistent with the water quality goals. Some assert that these two

public participation steps seek input on different questions and are

not interchangeable. Does the weight-of-evidence option discussed above

reduce the opportunity for meaningful public participation in the

standards setting process by making it more difficult for the public to

determine which water quality criteria will apply to which water

bodies, and, as a result, what the water quality goals for an

individual water body are? EPA is considering how a weight-of-evidence

approach might be implemented in a manner that does not restrict the

opportunities for meaningful public participation in the water quality

goal setting process.

Request for Comments on Independent Application

EPA requests comment on the following questions:

1\. What is the rationale for modifying the independent application

policy as it pertains to NPDES permitting? Under what circumstances

could it be justified?

2\. If there are circumstances where an approach other than

independent application is acceptable, should any one type of water

quality data receive greater weight and why?

3\. How should States and Tribes evaluate effluent data generated

using chemical, toxicity and biological methods in determining

reasonable potential to cause or contribute to an impairment?

4\. Would checks or oversight mechanisms be necessary to ensure that

where decisions about reasonable potential are based on chemical,

toxicity and biological methods, such decisions are made with

integrity? For example, EPA or public oversight?

5\. Are there any cases which indicate that either chemical-

specific, whole effluent toxicity or biological approaches do not

legitimately represent some aspect of use attainment?

6\. Should EPA explicitly incorporate into the water quality

standards regulation the independent application policy?

7\. Should independent application be addressed the same or

differently for permitting than for assessment and use attainment

decisions under 305(b) reporting and 303(d) listing?

8\. If EPA were to separate the use of independent application in

determining the use attainment status of a water body from the use of

independent application when determining reasonable potential for an

effluent, what approach, independent application, weight-of-evidence,

or hierarchical, should be used for use attainment decisions? NPDES

permitting? What would the implications be if the programs used two

different policies?

9\. Would a policy allowing numeric criteria to not apply to all

waters where supported by scientifically defensible data be workable?

Would it unnecessarily complicate the regulatory program, for example

by delaying the issuance of permits? Are existing mechanisms of

criteria setting and permit issuance sufficiently flexible?

IV\. Summary and Potential Program and Regulation Changes

EPA believes that the water quality standards program and decisions

it yields will continue to be the focus of growing pressure and

scrutiny as solutions to remaining surface water quality problems in

this country are found to be increasingly elusive, difficult, and/or

expensive. The task set forth by the Clean Water Act is to improve

water quality even where it is difficult to do so. To accomplish this

task, EPA envisions a national water quality standards program in

which: the best possible information on whether designated uses are

being attained and how to attain and maintain them is available and

used; water quality criteria are selected from a wide-ranging menu of

scientifically sound criteria and tailored to each watershed; and

national norms of consistency and flexibility in State and Tribal water

quality standards are clear.

With this vision in mind, EPA, through this ANPRM, begins a review

of the water quality standards regulation in a public forum in an

attempt to identify possible amendments to the regulation and new

guidance or policy that may be needed to address three distinct

objectives: (1) eliminate any barriers to, and otherwise enhance State

and Tribal implementation of, watershed-based water quality planning

and management; (2) facilitate use of new, more integrated water

quality assessment and criteria science in water quality standards

programs, and; (3) improve the regulation so that it can be implemented

more efficiently and effectively (including cost-effectively).

The preceding pages of this ANPRM outline current regulatory

provisions, accompanying guidance and policy, and current practices in

the core areas of the water quality standards program. Each section of

the ANPRM identifies issues that have been raised to EPA that come out

of the collective experiences of States, Tribes, cities, industry and

environmental advocates, as well as EPA\'s experience. The issue

discussions are followed by specific questions that are intended to

elicit focused comments. It is important for commenters to focus on

these specific questions as a vehicle for developing comments. It is

equally important for commenters to develop ideas that address the

three objectives above in a more general sense and to identify the five

to seven highest priority issues the commenter believes EPA should

address in a follow-on regulatory proposal. EPA welcomes ideas on how

the water quality standards regulation, policy and or guidance can be

revised to facilitate water quality management on a watershed basis. In

requesting comment on eliminating barriers to and facilitating

implementation of watershed-based water quality planning and

management, EPA directs commenters\' attention primarily to the sections

on designated uses, criteria, antidegradation, mixing zones and

independent application. In requesting comment on how to facilitate use

of new, more integrated water quality assessment and criteria science

in water quality standards, EPA directs commenters\' attention primarily

to the sections on biological criteria, and independent application. In

requesting comment on how to improve the efficiency and effectiveness

(including cost-effectiveness) of the water quality standards program,

all sections of the ANPRM are relevant for review.

EPA seeks a water quality standards program that protects the

nation\'s waters as envisioned in the CWA, that establishes requirements

that are necessary to attain and maintain healthy and sustainable

ecosystems, and that is flexible enough for States and Tribes to

protect water quality and at the same time avoid costly requirements

that have little or no environmental benefit.

Below is a brief summary outline of the potential changes to the

water quality standards program and

\[\[Page 36804\]\]

regulation that are discussed and considered in this ANPRM. The list of

potential changes includes the potential changes to the program and

regulation on which EPA is specifically requesting comment. Each area

of potential change is discussed in detail in the specified section of

the ANPRM. It is possible that EPA will ultimately propose some of the

changes outlined below. It is also possible that EPA will conclude

based on the public comments it receives that some or all of the issues

presented in the ANPRM can be best addressed through non-regulatory

mechanisms such as guidance or policy.

A. Uses

1\. Refinement of use designations to achieve increased specificity

in aquatic life and recreation uses being protected.

2\. Minimum elements of a use attainability analysis (UAA).

3\. When is UAA required/not required?

a\. UAAs whenever an aquatic life use is designated (beyond

fishable/swimmable) to see if the use reflects the highest potential

for the water body.

b\. Periodic review of marginal or limited aquatic life use

designations.

c\. When is a use considered attainable?

d\. Conditions under which refinements in designated uses may be

considered actions not requiring analysis to support use removal and

alternatively the conditions under which such action is considered a

use removal requiring justification under Sec. 131.10(g).

e\. Circumstances under which UAA is required and circumstances

under which UAA must be reviewed.

4\. Removal of designated uses.

a\. Minimum aquatic life uses for all waters, because even degraded

water bodies support some form of aquatic life.

b\. Evaluate use removal provision at Sec. 131.1(10)(g) allowing

removal of a use due to the existence/operation of a dam.

c\. Clarify whether the physical factors reason for removing a use

includes removal of a recreational use due to poor physical access to

the water. Alternatively, the removal of a use for physical factors

could be limited to aquatic life uses only.

d\. Clarify in Sec. 131.10 that at least one of the six use removal

criteria must be met to remove any use, not just aquatic life and

recreation uses.

5\. Alternatives to use downgrade such as variances, temporary

standards and ambient-based criteria.

a\. Recognize site-specific criteria set to natural background

levels as a permissible alternative to use downgrade.

b\. Recognize site-specific criteria set to irreversible

anthropogenic background levels as a permissible alternative to use

downgrade.

B. Criteria

1\. Ambient Water Quality criteria for Aquatic Life Protection.

a\. Examination and possible interim revisions to EPA

recommendations on the duration and frequency of criteria excursions to

account for organism response model and population response model.

2\. Site-specific criteria and procedures.

a\. Specify that States and Tribes must have regulatory procedures

for establishing site-specific criteria.

b\. Minimum requirements for development of site-specific criteria.

3\. Narrative criteria and interpretation procedures.

a\. Identify additional methods for implementation of narrative

criteria.

b\. Clarify that States and Tribes are required to adopt narrative

criteria for all waters. (all States already have).

4\. Codification of CWA requirement to adopt numeric toxics

criteria.

a\. Define \`\`reasonable expectation\'\' under 303(c)(2)(B).
(\`\`States

and Tribes may adopt numeric chemical-specific criteria for those

stream segments where the State or Tribe determines that the priority

toxic pollutants for which EPA has issued CWA section 304(a) criteria

guidance are present and can reasonably be expected to interfere with

designated uses.\'\' emphasis added)

5\. Chemical criteria beyond priority pollutants.

a\. Develop and recommend or require criteria for certain non-

priority pollutants.

6\. Numeric values in the absence of criteria or data sufficient for

criteria.

a\. States and Tribes develop method for derivation of alternative

values where minimum data requirements for criteria not satisfied.

Specific EPA derivation procedure or guidelines.

7\. Require or recommend that State and Tribes adopt numeric

toxicity criteria.

8\. Sediment quality criteria.

a\. Require or recommend that States and Tribes adopt sediment

criteria (narrative or numeric).

b\. Specify in regulation that States and Tribes have the

flexibility to adopt sediment quality criteria.

9\. Biological criteria.

a\. Require or recommend that States and Tribes adopt biological

criteria (narrative or numeric).

b\. Specify in regulation that States and Tribes have the

flexibility to adopt biological criteria.

c\. Specify linkage between biological criteria and stressor

identification.

10\. Wildlife Criteria.

a\. Recognize in regulatory text that wildlife criteria are valid

forms of water quality criteria.

b\. Recognize in regulatory text that wildlife criteria endpoints

other than bioaccumulation endpoints are valid bases for wildlife

criteria.

11\. Physical criteria: Existing and potential future role of.

a\. Identify physical criteria such as habitat (including clean

sediment) and hydrologic balance criteria in 40 CFR 131 as valid forms

of criteria that States and Tribes can adopt in their water quality

standards.

12\. Human Health Criteria.

a\. Higher fish consumption assumptions for site-specific or

regional situations when subpopulations that are highly exposed have

been identified.

b\. Clarification of the use of MCLs and MCLGs in State and Tribal

water quality standards.

C. Antidegradation

1\. Minimum elements of State and Tribal antidegradation

implementation procedures.

a\. Revise regulation to include the minimum elements of a State and

Tribal antidegradation implementation method.

b\. Revise the regulation to explicitly say that State and Tribal

antidegradation implementation procedures (in addition to just the

policy) must be submitted in triennial review package and are

reviewable by EPA.

2\. Tier 1 protection (protection of existing uses).

a\. Define or clarify what constitutes loss of an existing in-stream

water use.

b\. Specify that a clear approach to maintaining and protecting

existing uses that may not be adequately protected by strict

application of water quality criteria is a required element of an

antidegradation implementation procedure.

3\. Waters covered by tier 2 level protection.

a\. Clarify waters subject to tier 2 level protection.

b\. Clarify tier 2 provision requiring all cost effective and

reasonable best management practices for nonpoint sources prior to

allowing a lowering of water quality.

c\. Clarify that States and Tribes are to consider the 303(d)

listing status of a water body, and the information supporting that

status, when determining whether a proposed activity that is expected

to degrade water quality in that water body can be authorized under

tier 2 of the State\'s or Tribe\'s antidegradation provisions.

\[\[Page 36805\]\]

4\. Outstanding national resource water (ONRW) classification, level

of protection, and public role in nominating.

a\. Public nomination of ONRWs.

b\. Level of protection afforded to ONRWs.

5\. Creation of Antidegradation tier 2.5.

a\. Revise the regulation to explicitly recognize tier 2.5

protection.

D. Mixing Zone Policy and Implementation Procedures

1\. Specify that, to use mixing zones, States and Tribes must

indicate in their water quality standards whether they allow mixing

zones, conditions under which mixing zones are allowed, minimum

requirements for mixing zones.

2\. Procedures and decision criteria used in addressing complete and

incomplete mixing.

3\. Site-specific technical justification for rapid and complete mix

assumption.

4\. State and Tribe policies and procedures to address rate of

mixing.

5\. Clarify in regulation that narrative criteria apply in mixing

zones.

6\. Restrict Mixing zones for bioaccumulative chemicals of concern.

E. Applicability of Water Quality Standards to Wetlands

1\. Clarify in 40 CFR Part 131 that wetlands with interstate

commerce connection are waters of the U.S. requiring water quality

standards.

F. Evaluation of EPA Policy of Independent Application (IA)

1\. Increase use of chemical, toxicological, physical and biological

data in making water body assessments in a consistent and

scientifically defensible manner.

2\. Specify how, and the circumstances under which, different forms

of assessments (chemical, toxicological, physical and biological) can

be used together to determine:

a\. When a designated aquatic life use is or is not attained,

b\. The type and value of criteria that should apply to a water, and

c\. When water quality-based effluent limits are required in a

permit.

3\. Specify the adequate data base and level of rigor necessary in

biological assessments to support a determination of full use support

despite differences in assessment results.

In addition to the potential program and regulation changes

outlined above, EPA is also requesting comment on the costs and

benefits and potential reporting and record keeping requirements that

might be associated with these changes. These issues are discussed more

fully in the next section.

V. Regulatory Assessment Requirements

A. Executive Order (E.O.) 12866, Regulatory Planning and Review

Under Executive Order 12866, \[58 Federal Register 51,735 (October

4, 1993)\] the Agency must determine whether the regulatory action is

\`\`significant\'\' and therefore subject to Office of Management and

Budget (OMB) review and the requirements of the Executive Order. The

Order defines \`\`significant regulatory action\'\' as one that is
likely

to result in a rule that may:

\(1\) Have an annual effect on the economy of \$100 million or more or

adversely affect in a material way the economy, a sector of the

economy, productivity, competition, jobs, the environment, public

health or safety, or State, local, or tribal governments or

communities;

\(2\) Create a serious inconsistency or otherwise interfere with an

action taken or planned by another agency;

\(3\) Materially alter the budgetary impact of entitlements, grants,

user fees, or loan programs or the rights and obligations of recipients

thereof; or

\(4\) Raise novel legal or policy issues arising out of legal

mandates, the President\'s priorities, or the principles set forth in

the Executive Order.

While this advance notice of proposed rule making establishes no

regulatory requirements it could ultimately result in a rule that would

satisfy one or more of the above criteria. It has therefore been

determined that this action is a \`\`significant regulatory action\'\'

under the terms of Executive Order (E.O.) 12866. As such this action

was submitted to OMB for review. Changes made in response to OMB

suggestions or recommendations have been documented in the public

record.

Under the terms of E.O. 12866, EPA is to prepare for any

significant regulatory action an assessment of its potential costs and

benefits. If that action satisfies the first of the criteria listed

above, this assessment must include, to the extent feasible, a

quantification of these costs and benefits, the underlying analyses

supporting such quantification, and an assessment of the costs and

benefits of reasonably feasible alternatives to the planned regulation.

Because the purpose of this notice is to initiate a structured national

debate on a broad set of issues rather than to propose specific

regulatory changes, it is not feasible to quantify the costs and

benefits of any resulting regulations at this time. The Agency is

aware, however, that this notice could lead to a regulatory action for

which the preparation of a quantitative assessment of costs and

benefits would be appropriate. The Agency is thus requesting comment on

the costs and benefits of any of the possible regulatory changes

discussed in this notice, as well as on appropriate methodologies for

assessing them. The Agency would be particularly interested to hear

from States and Tribes that may already have experience implementing

some of the measures discussed in this Notice and may already have

prepared analyses of the costs and/or benefits of such measures. Other

members of the public are also encouraged to submit any data they may

have on the costs and benefits of specific measures (e.g., conducting

biological assessments).

B. The Regulatory Flexibility Act (RFA) as Amended by the Small

Business Regulatory Enforcement Fairness Act (SBREFA) of 1996

Under the RFA, (5 U.S.C. 601 et seq.), as amended by SBREFA, for

proposed rules, EPA generally is required to conduct an initial

regulatory flexibility analysis (IRFA) describing the impact of the

regulatory action on small entities as part of rulemaking. However,

under section 605(b) of the RFA, if the Administrator for the Agency

certifies that the rule will not have a significant economic impact on

a substantial number of small entities, EPA is not required to prepare

an IRFA. The requirement applies to proposed rules only and as this

notice is an ANPRM, these requirements do not apply to this notice.

C. Paperwork Reduction Act

Under the implementing regulations for the Paperwork Reduction Act,

an agency is required to certify that any agency-sponsored collection

of information from the public is necessary for the proper performance

of its functions, has practical utility, is not unnecessarily

duplicative of information otherwise reasonably accessible to the

agency, and reduces to the extent practicable and appropriate the

burden on those required to provide the information (5 CFR 1320.9). Any

proposed collection of information must be submitted, along with this

certification, to the Office of Management and Budget for approval

before it goes into effect. Most of the potential regulatory changes

discussed in this Notice could entail new reporting and record keeping

requirements for States and Tribes and/or members of the regulated

public. EPA

\[\[Page 36806\]\]

is interested in comments on any and all aspects of these potential

paperwork requirements, and in particular on how they should be

structured to fulfill the requirements that they have practical

utility, are not unnecessarily duplicative of other available

information, and are the least burdensome necessary to satisfy the

purposes of the Water Quality Standards Program.

Dated: June 25, 1998.

Robert Perciasepe,

Assistant Administrator for Water.

\[FR Doc. 98-17513 Filed 7-6-98; 8:45 am\]

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