36742 Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules

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.

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 OWDocket@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 (email: 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:

Category Examples of potentially affected entities

State, Tribes and Jurisdictional Governments ......................................... States, Tribes authorized to 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
Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules 36743

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 21⁄2

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
36744 Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules

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 qualitybased 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
Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules 36745

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 technologybased 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 technologybased 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
36746 Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules

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
Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules 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.
36748 Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules

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 qualitybased 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
Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules 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 makingprocess, 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

§ 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 subclassifications 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 subcategories 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 watershedspecific 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
36750 Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules

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
Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules 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 § 131.10 of the Federal

regulation (see § 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 decisionmaking 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 subcategory 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
36752 Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules

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

§§ 131.10 and 131.12 must be

considered together. The classification

requirements in § 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
Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules 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
36754 Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules

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

§ 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 § 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
Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules 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 {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
36756 Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules

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

§ 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

§§ 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

§ 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 § 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

§ 131.10(g) to ensure the § 131.10(g)

criteria are consistently interpreted and

applied, and to address whether review

under § 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
Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules 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 (§ 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

§ 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,
36758 Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules

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 § 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 bodyspecific 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 timelimited. 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
Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules 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 § 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 § 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 shortterm variances to individual dischargers

based on any of the six factors for

removing a designated use as listed at

§ 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 sourcespecific 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
36760 Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules

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 costeffective 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 § 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 shorterterm. 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;
Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules 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 SiteSpecific 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 sitespecific 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 sitespecific 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 preexisting criteria and the ambient-based

criteria).

EPA is interested in hearing

comments regarding these ambientbased 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 § 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 crossreferencing 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
36762 Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules

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 § 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 chemicalspecific 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 sitespecific 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
Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules 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 sitespecific 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 scientificallyderived 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 shortterm 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
36764 Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules

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-inten 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 oneday-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 sitespecific 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 sitespecific 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 sitespecific 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?
Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules 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 ecosystemspecific 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 QualityBased 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
36766 Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules

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 subsection (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 reservationwide 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
Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules 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 nonpriority 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 nonpriority 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
36768 Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules

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
Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules 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 nonionic organics concluded that: ‘‘these

criteria not be used as stand-alone, passfail 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
36770 Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules

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 biologicallybased 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.
Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules 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
36772 Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules

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
Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules 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. Humancaused 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 finegrained 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
36774 Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules

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 interrelated 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¥5, 10¥6, and 10¥7 for

informational purposes. Most States and

Tribes select either a 10¥5 or 10¥6 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¥5 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¥4 (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¥5 to 10¥7 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¥4 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¥4 to 10¥6 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¥4 risk level. Furthermore, EPA is

considering proposing the 10¥6 risk

level as the level that ensures protection

for all exposed population groups. As

stated before, all comments regarding

methodology, including risk levels,
Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules 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¥6

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 nonoccupational 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¥5 or 10¥6 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¥4 risk level. (EPA is

not proposing a national risk level of

10¥4 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 factfinding, 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 chemicalspecific 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
36776 Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules

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¥4 to 10¥6 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¥5 to 10¥7, 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 nonfish 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

× 10¥4 mg/kg/day, while the CWA

criterion utilized an ADI of 1.0 × 10¥3

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
Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules 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,
36778 Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules

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 nonenteric 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 regionspecific 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?
Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules 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 threetiered 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
36780 Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules

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 communitybased 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

§ 402 NPDES permits or CWA § 404

dredge and fill permits, any activity

requiring a CWA § 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
Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules 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 subcategories) can potentially provide more

protection by addressing more subtle

changes to the existing use. States and
36782 Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules

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’’ (§ 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-bywater 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 pollutantby-pollutant approach may result in

more waters receiving some degree of

tier 2 protection because it would cover
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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-bywater 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 lessdegrading 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-bypollutant 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
36784 Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules

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
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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

§ 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
36786 Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules

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 freeflowing. 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
Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules 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 21⁄2. 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 21⁄2. 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 21⁄2 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 21⁄2 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 21⁄2

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 21⁄2 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

§ 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
36788 Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules

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 sitespecific 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 qualitybased permit limit derivation methods

that were relatively simple to use and

could be implemented with little sitespecific 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.
Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules 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 EPAIssued 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-ofinitial 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 sitespecific 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 sitespecific 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
36790 Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules

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 qualitybased 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 incompletemix 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.
Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules 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 postexposure 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 sitespecific 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
36792 Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules

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
Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules 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-toone 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× 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 sitespecific 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)?
36794 Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules

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
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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 costeffective. 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 nonchemical 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.,
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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 chemicalspecific 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 chemicalspecific 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 chemicalspecific 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 sitespecific 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
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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 nonattainment 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-ofevidence’’ 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,
36798 Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules

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 weightof-evidence approach would be in

establishing criteria. In addition, as

discussed below, EPA is interested in

evaluating the use of a weight-ofevidence 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-ofevidence 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-ofevidence 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
Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules 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 sitespecific 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-ofevidence 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
36800 Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules

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 qualitybased 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
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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-ofevidence 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 qualitybased 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 chemicalspecific 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 sitespecific criteria. In any case, chemicalspecific and toxicity criteria are proven

and necessary bases of water qualitybased 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
36802 Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules

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 chemicalspecific 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 sitespecific 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
Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules 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-ofevidence 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
36804 Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules

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

§ 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

§ 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 § 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.
Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules 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
36806 Federal Register / Vol. 63, No. 129 /Tuesday, July 7, 1998 / Proposed Rules

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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