Tuesday
July 7, 1998
Part II
Environmental
Protection Agency
40 CFR Part 131
Water Quality Standards Regulation;
Proposed Rule
36741
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Federal Register/Vol. 63, No. 129/Tuesday, July 7, 1998/Proposed Rules
ENVIRONMENTAL PROTECTION
AGENCY
40 CFR Part 131
[FRL-OW-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 OW-
Docket@epamail.epa.gov. The record is
available for inspection from 9:00 to
4:00 p.m., Monday through Friday,
excluding legal holidays at the Water
Docket, East Tower Basement, USEPA,
401 M St., S.W., Washington, D.C. For
access to docket materials, please call
(202) 260-3027 to schedule an
appointment.
FOR FURTHER INFORMATION CONTACT: Rob
Wood at U.S. EPA Standards and
Applied Science Division (4305), 401 M
Street SW, Washington, DC 20460 (e-
mail: WOOD.ROBERT@EPA.GOV)
(telephone: 202-260-9536).
SUPPLEMENTARY INFORMATION: EPA will
hold a series of full-day public meetings
for the purpose of discussion and debate
on the issues presented in this notice.
EPA plans to hold the public meetings
during the 180-day public comment
period on this notice. Dates, times and
locations of public meetings will be
announced to the public.
A. Potentially Affected Entities
This ANPRM by itself will have no
regulatory impact or effect. The ANPRM
does contain EPA interpretations of core
areas of the regulation as well as EPA
thinking about how the regulation may
need to be changed. As discussed in
more detail below, this ANPRM marks
the beginning of a national dialogue on
possible changes to the water quality
standards regulation and program. If
changes to the regulation are proposed
and ultimately made final, to the extent
such changes would require and/or
authorize changes to State and Tribal
water quality standards, States and
authorized Tribes would be affected. If
changes to State and Tribal water
quality standards result from any final
rule that EPA may promulgate in the
future, entities subject to compliance
with State or Tribal water quality
standards would also potentially be
affected. For example, States and Tribes
authorized to implement the National
Pollutant Discharge Elimination System
(NPDES) Permit Program would need to
ensure that permits they issue include
any limitations on discharges necessary
to comply with any water quality
standards established as a result of any
subsequent final rulemaking. Therefore,
entities discharging pollutants to waters
of the United States under NPDES could
be affected by subsequent proposed and
final rulemaking. Categories and entities
that may ultimately be affected include:
Category
State Tribes and Jurisdictional Governments
Industry
Municipalities
Examples of potentially affected entities
States Tribes authorized to administer water quality standards and
risdictional governments.
Industrial dischargers of pollutants to waters of the U.S.
Publicly-owned treatment works discharging pollutants to waters of
U.S.
hi-
tho
This table is not intended to be
exhaustive, but rather provides a guide
for readers regarding entities that could
be affected by any subsequent final
rulemaking. If you have questions
regarding the applicability of this action
to a particular entity, consult the person
listed in the preceding FOR FURTHER
INFORMATION CONTACT section.
B. Water Docket Information
The record for this notice has been
established under docket number W-
98-01 and includes supporting
documentation. When submitting
written comments to the Water Docket,
(see ADDRESSES section above) please
reference docket number [W-98-01] and
submit an original and three copies of
your comments and enclosures
(including references). To ensure that
EPA can read, understand and therefore
properly respond to comments, the
Agency would prefer that commenters
cite the specific question(s) in the notice
to which each comment refers. The
questions presented in this notice for
public comment are organized by
subsection and numbered. Each
question has a unique number (for
example III.B.3.a., question 1) for this
purpose.
Comments must be received or
postmarked by midnight January 4,
1999. Commenters who want EPA to
acknowledge receipt of their comments
should enclose a self-addressed,
stamped envelope. No facsimiles (faxes)
will be accepted.
Electronic comments are encouraged
and may be submitted to the Water
Docket (see ADDRESSES section above).
Electronic comments must be submitted
as an ASCII file or a WordPerfect file
avoiding the use of special characters
and any form of encryption. Electronic
comments must be identified by the
docket number, [W-98-01], and be
received by midnight of January 4, 1999.
Comments and data will also be
accepted on disks in WP5.1 format or
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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. 40CFR 131.12 (a)(l) "tier 1"
a. Tier 1 Implementation
4. 40CFR131.12 (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. 40CFR131.12 (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 2l/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.G.) 12866,
Regulatory Planning and Review
B. The Regulatory Flexibility Act (RFA) as
Amended by the Small Business
Regulatory Enforcement Fairness Act
(SBREFA) of 1996
C. Paperwork Reduction Act
I. Purpose and Objectives of This
ANPRM
A. General Purpose and Vision
On February 14, 1998, the visionary
"Clean Water Action Plan" was
announced by the Administrator of EPA
and the Secretary of Agriculture. The
"Clean Water Action Plan" is a
blueprint for restoring and protecting
the Nation's precious water resources. A
key element of the plan is advancement
of the watershed approach to water
quality protection. EPA's belief is that
refining designated uses and
implementing better more integrated
water quality criteria to protect the
refined uses, two important themes of
this ANPRM, are essential steps in
carrying out the blueprint presented.
Revision of the water quality standards
regulation can be an essential
component in implementing the vision
of the "Clean Water Action Plan."
States, Tribes and EPA have
developed functional water quality
standards programs under the current
regulation and these programs have
provided the basis for significant water
quality improvement in the United
States. Simply put, the current
regulation is not broken. Rather, with
the renewed interest in watershed
management combined with improved
methods for water quality assessment, a
comprehensive evaluation for the
purpose of strengthening the regulation
is appropriate at this time. EPA and the
public need to examine whether
changes in the regulation could enhance
water quality management on a
watershed basis and focus resources on
areas of greatest concern. A review of
the regulation will also complement
similar outreach discussions EPA is
currently undertaking for the purposes
of reviewing the water quality planning
and management and total maximum
daily load (TMDL) programs as well as
aspects of the NPDES program. EPA is
committed to ensuring that these
programs, combined, form an even
stronger integrated basis for water
quality planning, priority setting and
implementation on a watershed basis.
In recent years there has been a rising
level of scrutiny placed on water quality
standards and the State, Tribal and EPA
decisions based on water quality
standards. The increased scrutiny comes
from virtually all parties affected by
water quality-based decisions and is
evidenced by the growing tide of
challenges to State standards, EPA
policies and guidance, and individual
water quality-based decisions.
Remaining water quality problems in
the U.S. are often difficult to assess,
define and solve. Once agreed upon, the
solutions will be less conventional than
we are used to and may result in
different regulatory approaches.
Examples of such problems include
aquatic and riparian habitat destruction
from municipal and agricultural run-off
and fish tissue contamination from
chemicals with many and diverse
sources.
EPA believes that this scrutiny will
continue and that an evaluation of the
water quality standards program and its
regulatory and policy underpinnings to
identify where these program
underpinnings may need to be
strengthened, clarified or revised is
imperative. Our task under the Clean
Water Act is to ensure adequate water
quality even where it is difficult to do
so. To accomplish this task, EPA
envisions a national water quality
standards program in which: the best
possible information on whether
designated uses are being attained and
how to attain and maintain them is
available and used; water quality
criteria are selected from a wide-ranging
menu of scientifically sound criteria
that can be tailored to each watershed;
national norms of consistency and
flexibility in State and Tribal water
quality standards are clear; and
innovative, cost-effective approaches are
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encouraged. To realize this vision, EPA
believes that a structured national
debate is needed to identify a focused
set of issues that may ultimately lead to
changes to the water quality standards
regulation and policy.
The ANPRM process allows EPA to
begin this work by consulting with all
interested parties to find out what
changes, if any, are necessary and
desirable, to make the water quality
standards regulation more responsive to
current needs and to identify
opportunities for further clarifications of
policy and guidance by EPA. In the
fourteen years since EPA last revised the
water quality standards regulation,
interested parties have gained
considerable experience in developing
and implementing water quality
standards. This experience will provide
valuable information for review of these
regulations.
The most significant shift in water
quality management programs in recent
years has been the increased emphasis
on the use of watershed based programs.
It is increasingly apparent that EPA,
States, Tribes, municipalities and the
public share a common view that water
quality programs, including water
quality standards, can be better tailored
to the characteristics, problems, risks
and implementation tools available in
individual watersheds or basins with
meaningful involvement of the local
communities. The water quality
standards regulation should ensure that
States and Tribes have the flexibility to
define the water quality standards and
hence the environmental objectives of a
water body according to the
characteristics of the ecosystem and the
needs of the water's users within the
bounds established under the CWA. The
regulation must allow the States and
Tribes to tailor water body use
designations and criteria to protect these
uses within individual basins or
watersheds based on the needs in the
basin. The present use of broad,
jurisdiction-wide use classifications and
lists of associated chemical criteria may
be at once too general and too narrow
for some waters, lacking the refinement
necessary to tailor water quality
management actions to specific
watersheds. This general approach
reflects the historical lack of
information on specific basins or water
bodies and the need to ensure that all
waters receive adequate protection.
Additionally, it should be made clear
how much flexibility States and Tribes
have to adjust use designations as
information improves about whether a
designated use or a higher use can be
attained and to reflect natural and
human caused changes in water quality
that may have occurred. The challenge
for EPA, States and Tribes is to identify
and use opportunities to refine use
designations for waters where it makes
sense and better match the water quality
criteria to the refined use, thus making
water quality standards more flexible. In
addition, to more effectively implement
the standards, the criteria that are used
need to better integrate multiple
stressors and their cumulative impacts
in order to more effectively protect
designated uses.
Significant scientific advancements in
recent years have added to the ability to
assess environmental impacts and risks
related to changes in water quality. As
they are further developed, new and
emerging sophisticated and integrated
analytical tools such as bioassessment,
criteria for bioaccumulative chemicals,
sediment quality criteria and toxicity
assessments will increasingly allow
States, Tribes, EPA and the public to
characterize better the ecological
condition of water resources. At present,
this improving capability, used in a
tailored watershed planning and
management framework, can enhance
the ability of States and Tribes to
characterize and protect locally agreed
upon goals for maintaining and
protecting the chemical, physical and
biological integrity of individual basins.
In the long term, chemical, physical and
biological assessment methods will
continue to improve. As they do, the
water quality standards program should
be designed to accommodate effectively
the new science. In the meantime,
progress should not be stalled by
incomplete knowledge.
With the new science and assessment
methodologies, however, come new
challenges for States and Tribes to
identify the resources necessary to make
use of these advances. One of the main
themes of this ANPRM is the need for
better data, and new types of data, in
order to support a more refined
approach to water quality protection.
EPA recognizes, however, that efforts to
obtain such data, and develop the
analytical capacity to integrate it into
existing regulatory programs, could
encounter significant resource
constraints in some States and Tribes.
EPA is well aware that in order for a
new, data-intensive, watershed-specific
approach to succeed, it must be
workable for the States and Tribes that
will have to implement it. EPA
welcomes comments regarding concerns
over resource constraints and ideas for
how to address them.
The water quality standards program
must protect the nation's waters as
envisioned in the CWA. It must
establish requirements that are
necessary to attain and maintain
healthy, sustainable ecosystems. It must
be flexible enough for States and Tribes
to ensure that standards are protecting
water quality in a way that makes sense.
EPA seeks to avoid a program that
results in costly requirements that have
little or no environmental benefit. Thus
EPA intends to use its experience and
that of the States, Tribes, municipalities,
the regulated community,
environmental groups and the general
public in implementing and utilizing
water quality standards over the last
fourteen years, to evaluate the
regulation and determine if changes are
needed to allow greater State, Tribal and
local flexibility to develop innovative,
cost-effective ways to protect water
quality.
EPA may determine through the
ANPRM process that the concepts
described above can be better integrated
into water quality management decision
making through development of new or
revised policies and guidance rather
than revisions to the regulation. Because
of this possibility, EPA is reserving its
decision whether to propose and
finalize revisions to the regulation. At
minimum, EPA believes that any
revisions to the water quality standards
regulation should result in a regulation
that can be used to render protective,
tailored, site-specific water quality-
based decisions that bear reasonable
compliance costs for the regulated
community, as well as reasonable
implementation costs for States, Tribes
and EPA. At the same time, the
regulation should allow sufficient
flexibility to States and Tribes, if they
choose, to implement water quality
standards programs in a manner that is
no more burdensome than under the
existing regulation.
B. Objectives
In publishing this ANPRM, EPA is
beginning a review of the regulation in
a public forum in an attempt to identify
possible amendments to the regulation,
and new guidance or policy that may be
needed to address three distinct
objectives. They are: (1) to eliminate any
barriers and develop incentives to
enhance State and Tribal
implementation of watershed-based
water quality planning and
management; (2) to enhance State and
Tribal capability to incorporate current
criteria and water quality assessment
science into their water quality
standards programs, and; (3) to improve
the regulation so that it may be
implemented more efficiently and
effectively (including cost-effectively).
Meeting these three objectives, EPA
believes, will facilitate further water
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quality improvements locally and
nationally. EPA urges commenters to
keep all three main objectives in mind
when reviewing, analyzing and
commenting on this ANPRM.
II. Introduction to Water Quality
Standards
A. Statutory History
The first comprehensive legislation
for water pollution control was the
Water Pollution Control Act of 1948
(Pub. L. 845, 80th Congress). This law
adopted principles of State-Federal
cooperative program development,
limited federal enforcement authority,
and limited federal financial assistance.
These principles were continued in the
Federal Water Pollution Control Act
(Pub. L. 660, 84th Congress) in 1956 and
in the Water Quality Act of 1965. Under
the 1965 Act, States were directed to
develop water quality standards
establishing water quality goals for
interstate waters. By the early 1970's, all
the States had adopted such water
quality standards. Since then, States
have revised their standards to reflect
new scientific information, the impact
on water quality of economic
development and the results of water
quality controls.
Due to enforcement complexities and
other problems, an approach based
solely on water quality standards was
deemed too weak to make a difference.
The purely water quality-based
approach prior to 1972 lacked
enforceable Federal mandates and
standards, and a strong impetus to
implement plans for water quality
improvement. The result was an
incomplete program that in Congress'
view needed strengthening. In the
Federal Water Pollution Control Act
Amendments of 1972 (Pub. L. 92-500,
Clean Water Act or CWA), Congress
established the National Pollutant
Discharge Elimination System (NPDES)
whereby each point source discharger to
waters of the U.S. is required to obtain
a discharge permit. The 1972
Amendments required EPA to establish
technology-based effluent limitations
that are to be incorporated into NPDES
permits. In addition, the amendments
extended the water quality standards
program to intrastate waters and
required NPDES permits to be
consistent with applicable State water
quality standards. Thus, the CWA
established complementary technology-
based and water quality-based
approaches to water pollution control.
Now, after nearly 25 years of investment
in technology-based controls and some
$70 billion in sewage treatment plant
construction, attention is turning back
to water quality standards as a
mechanism to make improvements in
water quality beyond those that have
been achieved through technology-
based controls.
Water quality standards serve as the
foundation for the water-quality based
approach to pollution control and are a
fundamental component of watershed
management. Water quality standards
are State or Tribal law or regulation that:
define the water quality goals of a water
body, or segment thereof, by designating
the use or uses to be made of the water;
set criteria necessary to protect the uses;
and protect water quality through
antidegradation provisions. Although
the CWA gives EPA an important role in
determining appropriate minimum
levels of protection and providing
national oversight, it also gives
considerable flexibility and discretion to
States and Tribes to design their own
programs and establish levels of
protection above the national minimum.
States and Tribes adopt water quality
standards to protect public health or
welfare, enhance the quality of water,
and serve the purposes of the Act.
"Serve the purposes of the Act" (as
defined in Sections 101 (a), 101 (a)(2),
and 303(c) of the Act) means that water
quality standards should: (1) include
provisions for restoring and maintaining
chemical, physical, and biological
integrity of State and Tribal waters, (2)
provide, wherever attainable, water
quality for the protection and
propagation of fish, shellfish, and
wildlife and recreation in and on the
water ("fishable/swimmable"), and (3)
consider the use and value of State and
Tribal waters for public water supplies,
propagation offish 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
offish and wildlife, recreational
purposes, agricultural and industrial
water supplies and navigation;
3. Requires that State and Tribal
standards protect public health or
welfare, enhance the quality of water
and serve the purposes of the Act;
4. Requires that States and Tribes
review their standards every three years;
5. Establishes the process for EPA
review of State and Tribal standards,
including where necessary the
promulgation of a superseding Federal
rule in cases where a State's or Tribe's
standards are not consistent with
applicable requirements of the CWA or
in situations where the Administrator
determines that Federal standards are
necessary to meet the requirements of
the Act.
The decade of the 1970's saw State
and EPA attention focus on creating the
infrastructure necessary to support the
NPDES permit program and
development of technology-based
effluent limitations. While the water
quality standards program continued, it
was a low priority in the overall CWA
program. In the early 1980's, it began to
be recognized that greater attention to
the water quality-based approach to
pollution control would be needed to
effectively protect and enhance all of
the nation's waters.
The first statutory evidence of this
was the enactment of a CWA
requirement that after December 29,
1984, no construction grant could be
awarded for projects that discharged
into stream segments which had not, at
least once since December 1981, had
their water quality standards reviewed
and revised or new standards adopted
as appropriate under Section 303(c).
(Public Law 97-117, Section 24,
"Revised Water Quality Standards.")
The efforts by the States to comply with
this one-time requirement essentially
made the States' water quality standards
current as of that date for segments with
publicly-owned treatment works
(POTWs) discharging into them.
Additional impetus to the water
quality standards program occurred on
February 4, 1987, when Congress
enacted the Water Quality Act of 1987
(Pub. L. 100-4). Congressional
impatience with the lack of progress in
State adoption of standards for toxics
(which had been a national program
priority since the early 1980's) resulted
in the 1987 adoption of new water
quality standard provisions in the Water
Quality Act amendments. These
amendments reflected Congress'
conclusion that toxic pollutants in water
are one of the most pressing water
pollution problems. One concern
Congress had was that States were
relying, for the most part, on narrative
criteria to control toxics (e.g., "no toxics
in toxic amounts"), which made
development of effluent limitations in
permits difficult. To remedy this,
Congress adopted section 303(c)(2)(B),
which essentially required development
of numeric criteria for those water body
segments where toxic pollutants were
likely to adversely affect designated
uses.
The 1987 Amendments gave new
teeth to the control of toxic pollutants.
As Senator Mitchell put it, Section
303(c) (2) (B) requires "States to identify
waters that do not meet water quality
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standards due to the discharge of toxic
substances, to adopt numerical criteria
for the pollutants in such waters, and to
establish effluent limitations for
individual discharges to such water
bodies." (From Senator Mitchell, 133
Cong. Rec. S733.) To assist States in
complying with Section 303(c)(2)(B),
EPA issued program guidance in
December 1988 and instituted an
expanded program of training and
technical assistance.
Section 518 was another major
addition in the 1987 Amendments to the
Act. This section extended participation
in the water quality standards and 401
certification programs to certain Indian
Tribes. The Act directed EPA to
establish procedures by which a Tribe
could "qualify for treatment as a State,"
at its option, for purposes of
administering the standards and 401
certification programs. The Act also
required EPA to create a mechanism to
resolve disputes that might develop
when unreasonable consequences arise
from a Tribe and a State or another
Tribe adopting different water quality
standards on common bodies of water.
Furthermore, with the 1987
Amendments, the Act explicitly
recognized EPA's antidegradation policy
for the first time. The intent of the
antidegradation policy in EPA's
regulation was and is to protect existing
uses and the level of water quality
necessary to protect existing uses and to
provide a means for assessing activities
that may impact high quality waters and
ruling on whether such projects could
proceed. Section 303(d)(4) of the Act
requires that water quality standards in
those waters that meet or exceed levels
necessary to support designated uses
"may be revised only if such revision is
subject to and consistent with the
antidegradation policy established
under this section."
B. Regulatory History
In the late 1960's and early 1970's the
water quality standards program was
initiated and administered based on
minimal guidance and Federal
policies—many of which are still
reflected in the water quality standards
program today.
EPA first promulgated a water quality
standards regulation in 1975 (40 CFR
130.17, 40 FR 55334, November 28,
1975) as part of EPA's water quality
management regulations mandated
under Section 303(e) of the Act. As
discussed earlier, the standards program
had a relatively low priority during this
time. This was reflected in the minimal
requirements of the first Water Quality
Standards Regulation. Few requirements
on designating water uses and
procedures were included. The
Regulation was general, requiring
"appropriate" water quality criteria
necessary to support designated uses
and incorporating the antidegradation
policy. Toxic pollutants or any other
specific criteria were not mentioned.
Some States developed detailed water
quality standards regulations while
others adopted only general provisions
which proved to be of limited use in the
management of increasingly complex
water quality problems and created
disparities in requirements on regulated
entities. The few water quality criteria
that were adopted addressed a limited
number of pollutants and primarily
described fundamental water quality
conditions (e.g., pH, temperature,
dissolved oxygen and suspended solids)
or dealt with conventional pollutants.
In the late 1970s, EPA determined
that existing State water quality
standards needed to be better
developed. EPA moved to strengthen
the water quality program to
complement the technology based
controls. EPA amended the Water
Quality Standards Regulation to
explicitly address toxic criteria
requirements in State standards and
other legal and programmatic issues.
November 8, 1983 (54 FR 51400). This
regulation is more comprehensive than
its predecessor and includes more
specific regulatory and procedural
requirements. The 1983 regulation
created the concept of use attainability
analysis, added detail on the adoption
of numeric criteria including
authorization for site-specific criteria,
and listed specific procedural
requirements and definitions not
included in the original 1975 regulation.
The regulation specified the roles of the
States and EPA and the administrative
requirements for States in adopting and
submitting their standards to EPA for
review. It also delineated the EPA
requirements for review of State
standards and promulgation of federal
standards.
The 1983 regulation provided States
(and subsequently in 1991) Tribes with
the option of refining their use
designation process by allowing them to
establish subcategories of uses, such as
cold water and warm water aquatic life
designations. The 1983 regulation also
clarified that States (and subsequently
Tribes) may adopt discretionary policies
affecting the implementation of
standards, such as mixing zones, low
flows, and variances.
In support of the 1983 Regulation,
EPA simultaneously issued program
guidance entitled Water Quality
Standards Handbook (December, 1983).
The Handbook provided guidance on
the interpretation and implementation
of the Water Quality Standards
Regulation. This document also
contained information on scientific and
technical analyses that are used in
making decisions that would impact
water quality standards. EPA also
developed the Technical Support
Document for Water Quality-Based
Toxics Control (EPA 44/4-85-032,
September, 1985) (TSD) which provided
additional guidance for implementing
State water quality standards. In 1991,
EPA revised and expanded the TSD.
(EPA 505/2-90-001, March 1991). In
1994, EPA issued the Water Quality
Standards Handbook: Second Edition
(EPA-823-B-94-006, August 1994).
To accelerate compliance with CWA
section 303(c)(2)(B) (created by the 1987
Water Quality Act), EPA started action
in 1990 to promulgate numeric water
quality criteria for those States that had
not adopted sufficient water quality
standards for toxic pollutants. The
intent of the rulemaking, known as the
National Toxics Rule, was to strengthen
State water quality management
programs by increasing the level of
protection afforded to aquatic life and
human health through the adoption of
all available criteria for toxic pollutants
listed under 307(a) of the CWA (priority
pollutants) present or likely to be
present in State waters. This action
culminated on December 22, 1992, with
EPA promulgating Federal water quality
criteria for priority toxic pollutants for
14 States and Territories (see 57 FR
60848).
Subsequent to the promulgation of
criteria under the National Toxics Rule,
EPA altered its national policy on the
expression of aquatic life criteria for
metals. On May 4, 1995 at 60 FR 22228,
EPA issued a stay of several metals
criteria (expressed as total recoverable
metal) previously promulgated under
the National Toxics Rule for the
protection of aquatic life. EPA
simultaneously issued an interim final
rule that changed these metal criteria
promulgated under the National Toxics
Rule from the total recoverable form to
the dissolved form.
The Water Quality Standards
Regulation was amended in 1991 to
implement Section 518 of the Act to
expand the standards program to
include Indian Tribes (56 FR 64893,
December 12, 1991). EPA added 40 CFR
131.7 to describe the requirements of
the issue dispute resolution mechanism
(to resolve unreasonable consequences
that may arise between a Tribe and a
State or another Tribe when differing
water quality standards have been
adopted for a common body of water)
and 40 CFR 131.8 to establish the
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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.
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This is an appropriate time to begin
a structured national debate aimed at
identifying the focused changes
necessary to strengthen the
underpinnings of water quality
standards and implementation. In the
fourteen years since the regulation was
last revised, there have been numerous
scientific developments, statutory
changes, court decisions, and
implementation issues affecting the
water quality standards program. The
shift in program focus beyond just
chemical contamination to include
ecosystem protection and watershed
approaches necessitates reexamining
basic program concepts. In addition,
there is an opportunity to address
possible barriers to effective water
quality improvements where it is
determined that regulatory changes are
possible under existing law.
In recent years, EPA has heard from
the States and Tribes as well as the
environmental and regulated
communities regarding the necessity
and focus of a revision to the water
quality standards regulation. As
indicated by the wide range of issues
and options presented in this advance
notice, views of the different
stakeholder groups often differ
considerably. Many stakeholders believe
that a revised regulation is needed for
continued improvements in water
quality protection. Others believe
changes are needed to allow more
flexible, cost-effective approaches by
States and Tribes. Conversely, many
stakeholders have said that the
regulation is sufficient and does not
need to be reviewed.
A key issue presented here relates to
the degree of specificity necessary
should EPA revise the regulation. There
are many who support a more flexible
regulation to allow States and Tribes to
address new and changing
circumstances. Under a more flexible
regulation, States and Tribes could more
easily tailor their programs to deal with
pressing water quality restoration and
protection needs that are not well
addressed presently. Others support a
regulation with more specific regulatory
requirements. The latter would promote
a more consistent minimal level of
protection in State and Tribal water
quality standards, provide more clarity
on standards issues, and serve as a
stronger tool in encouraging States and
Tribes to take appropriate restoration
and protection actions. EPA urges
commenters to consider the appropriate
balance between flexibility, national
consistency, and consistency within
States and Tribes when commenting on
any of the ideas presented in this notice.
One of the outcomes of this ANPRM
and follow-on actions can be
establishment of a clearer set of national
minimum policies and implementation
procedures on which EPA will reliably
and predictably base its approval and
disapproval decisions on State and
Tribal water quality standards
submittals. EPA remains committed to
making consistent decisions from State
to State and Tribe to Tribe and State to
Tribe to meet our obligation to ensure
an appropriate level of protection
nationally and that the goals of the Act
are achieved. Clarifying these national
norms will serve to better articulate the
norms of protection from State to State
and Tribe to Tribe and State to Tribe
and also to clarify national norms of
flexibility. Defining the appropriate
level of consistency, in turn, defines the
appropriate degree level of flexibility. In
addition, establishing norms of
consistency and flexibility should help
to resolve State or Tribal differences
with EPA on water quality standards
early in the process, before the
approval/disapproval stage.
While the following discussion
describes specific areas and issues for
public review, the public is welcome to
comment on any aspect of the water
quality standards program. EPA
emphasizes, however, that publication
of this Notice does not commit the
Agency to proceeding with a regulatory
change. EPA has not decided whether it
will, in fact, propose regulatory
amendments, and, if proposed, how
extensive that effort might be. This
decision will be made after considering
the comments received and the need to
address other priority activities as well
as any Congressional and Executive
Branch directives. A potential outcome
of this public review may be additional
guidance and/or policies rather than
regulatory changes.
EPA has not determined the next
steps it will take after evaluation of all
the comments received on this ANPRM.
It is likely that any follow-on proposed
rule to amend 40 CFR 131 would focus
on a relatively narrow set of issues and
that many other issues could be
resolved through policy and guidance.
EPA requests that commenters identify
the five to seven issues considered
highest priority for possible regulatory
amendments. The summary section at
the end of this notice contains a brief
summary of the potential changes to the
water quality standards regulation that
are discussed and considered in this
ANPRM. The list of potential changes
includes the full range of potential
changes to the regulation on which EPA
is specifically requesting comment.
Each potential change to the regulation
is discussed in detail in the
corresponding section of the ANPRM.
B. Uses
1. Background
Section 131.10 of the current
regulation describes States' and
authorized Tribes' responsibilities for
designating and protecting uses. The
regulation requires that States and
Tribes specify the water uses to be
achieved and protected; requires
protection of downstream uses; allows
for sub-category and seasonal uses, for
instance, to differentiate between cold
water and warm water fisheries; sets out
minimum attainability criteria; lists six
factors of which at least one must be
satisfied to justify removal of designated
uses which are not existing uses;
prohibits removal of existing uses;
establishes a mandatory upgrading of
uses which are existing but not
designated; and establishes conditions
and requirements for conducting use
attainability analyses.
These provisions make a distinction
between existing and designated uses
and set out specific requirements to
ensure protection of these two broad use
categories. Designated uses are defined
as those uses specified in water quality
standards for each water body or
segment whether or not they are being
attained. EPA interprets existing uses as
those uses actually attained in the water
body on or after November 28, 1975 (the
date of EPA's initial water quality
standards regulation), whether or not
they are included in water quality
standards. 40 CFR 131.3(e). Designated
uses focus on the attainable condition
while existing uses focus on the past or
present condition. Section 131.10 then
links these two broad use categories in
a manner which intends to ensure that
States and Tribes designate appropriate
water uses, reflecting both the existing
and attainable uses of each water body.
For this discussion it is important to
consider both the distinction between
and linkage of designated and existing
uses.
It is in designating uses that States
and Tribes establish the environmental
goals for their water resources, and it is
in designating uses that States and
Tribes are allowed to evaluate the
attainability of those goals. Because
water quality standards perform the
dual function of establishing water
quality goals and ultimately serving as
the regulatory basis for water quality-
based treatment controls and strategies,
typically, although not exclusively, via
water quality criteria protecting those
uses, a State or Tribe often weighs the
environmental, social and economic
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consequences of its decisions in
designating uses. The regulation allows
the State or Tribe some flexibility in
weighing these considerations and
adjusting these goals over time.
Reaching a conclusion on the uses that
appropriately reflect the potential for a
water body, determining the
attainability of those goals, and
appropriately evaluating the
consequences of a designation, however,
can be a difficult and controversial task.
Appropriate application of this process
involves a balancing of environmental,
scientific, technical, and economic and
social considerations as well as public
opinion and is therefore one of the most
challenging areas of the current
regulation.
To direct this decision making-
process, the regulation establishes
requirements that must be followed
when designating uses or concluding
that attaining a use is infeasible. When
performing this attainability analysis, a
State or Tribe considers physical,
chemical, biological and economic
factors that may limit the potential for
achieving the goal use.
EPA's current water quality regulation
effectively establishes a "rebuttable
presumption" that "fishable/
swimmable" uses are attainable and
therefore should apply to a water body
unless it is affirmatively demonstrated
that such uses are not attainable. EPA
believes that the rebuttable presumption
policy reflected in these regulations is
an essential foundation for effective
implementation of the Clean Water Act
as a whole. The "use" of a water body
is the most fundamental articulation of
its role in the aquatic and human
environments, and all of the water
quality protections established by the
CWA follow from the water's designated
use. This approach preserves States' and
Tribes' paramount role in establishing
water quality standards, in this instance,
in weighing any available evidence
regarding the attainable uses of a
particular water body. The rebuttable
presumption approach does not restrict
the discretion that States and Tribes
have to determine that "fishable/
swimmable" uses are not, in fact,
attainable in a particular case. Rather, if
the water quality goals articulated by
Congress are not to be met in a
particular water body, the regulations
simply require that such a
determination be based upon a credible,
"structured scientific assessment" of
use attainability.
Because there is a presumption that
the uses specified in sections 101 (a) (2)
and 303(c) of the Clean Water Act are
attainable (protection and propagation
of fish, shellfish and wildlife and
recreation in and on the water
[ 101 (a) (2) ]; public water supplies,
propagation offish 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 sub-
classifications which identify different
levels of protection. For example, some
States simply specify "water supply" as
a use classification applicable
throughout the State while others may
identify several specific sub-categories
related to the quality of the raw water
supply and anticipated treatment
requirements. Similarly, some States
designate general "aquatic life" uses
while others list a variety of sub-
categories based on a range of aquatic
community types which may include
descriptions of core aquatic species
representative of each sub-category.
Although a variety of approaches have
evolved and become established in State
and Tribal programs, the current
regulation is not specific about the level
of precision States or Tribes must
achieve in designating uses.
There are advantages and drawbacks
for either the general or specific use
classification systems and it is not clear
that either is necessarily superior in
ensuring full protection of State or
Tribal water quality. There is, however,
a need for the use designation process,
whether implementing a general or
specific classification system, to clearly
articulate and differentiate intended
levels of protection with enough
specificity so that decision-makers can
appropriately develop and implement
the standards on a site-or watershed-
specific basis and so that the public can
understand, identify with, and influence
the goals set for waters they care about.
Lack of precision in uses and criteria
assigned to protect those uses can
inadvertently result in either a lesser or
greater level of protection than was
actually intended when the water
quality standards were adopted.
Although the designated use specificity
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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
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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 decision-
making such as is anticipated in
implementing watershed or place-based
initiatives?
2. Where a State or Tribe utilizes
broadly-defined designated uses, could
the desired level of specificity be
adequately addressed in State or Tribal
standards that clearly articulate the
intent of the designated uses as they
would apply to specific waters of the
State or Tribe?
3. If EPA were to specify a required
level of precision in establishing use
categories, what factors should be
considered in prescribing a level of
specificity? That is, what factors should
be considered in striking a balance
between specificity sufficient to ensure
uses are afforded an appropriate level of
protection and flexibility/efficiency
needed to allow widespread application
of the classification system?
4. At a minimum, should the
regulation require that State and Tribal
aquatic life use categories include a sub-
category or sub-categories that may be
assigned to protect aquatic communities
that do not include a "fishery"?
Alternatively, should the regulation
explicitly reflect EPA's current
interpretation of the regulations to the
effect that State and Tribal aquatic life
classification systems protect a range of
aquatic communities whether or not
there are sport or commercial fish (or
any fish) present?
5. Should the use attainability
requirements in 131.10(j)(2) be modified
to recognize situations where
scientifically defensible less stringent
criteria may be appropriate for refined
uses which reflect the reference
condition for particular waters?
3. Existing Uses
a. Protection of Existing Uses. The
requirement to protect existing uses is
addressed in two places in the current
regulation—Section 131.10, designation
of uses and Section 131.12,
antidegradation. (see discussion of
antidegradation, "tier 1", in section III.D
of this document) As discussed in the
background section above, the
regulation defines "existing uses" as
"those uses actually attained in the
water body on or after November 28,
1975, whether or not they are included
in the water quality standards." (40 CFR
131.3(e)) As a result, the focus of
existing uses, is on the past or present
condition of the water body.
Furthermore, by establishing
requirements prohibiting the removal of
existing uses and ensuring those uses
will be appropriately recognized in
State and Tribal water quality standards,
the current regulation ensures that the
better of the past or present condition,
at a minimum, will be maintained and
protected. Determining whether or not
an existing use has occurred in the past
or is currently in place is not always a
straightforward task, however, and over
the years, a number of questions have
been raised about exactly what the
"existing use" provisions in 131.10
require. These questions generally fall
into two categories: (1) what is the link
between existing uses and the State or
Tribal use classification system? and (2)
what is the relationship between
existing uses, existing water quality and
potential uses, i.e. uses that may be
attainable in the water body whether or
not those uses are presently designated
for the water body or are presently being
attained?
The first question addresses the
relationship between the existing use
protection provisions in Section 131.10
and State or Tribal use classification
systems. There appears to be some
confusion on this point. The confusion
seems to center on what may appear to
be conflicting mandates—protect what
is there and allow no further erosion of
water quality, and appropriately
designate the existing use in regulation
using the established classification
system. The existing use definition and
the requirement that existing uses be
protected suggests to some that the
description of existing uses is
constrained by the way in which a State
or Tribe has described its designated
uses in its classification system. That is,
they argue that an existing use, to be
adequately protected, needs to fit into
one of the categories or sub-categories
established in State or Tribal regulation,
and as a result, a decision about
whether or not a use is "existing" is
likewise constrained by the use
descriptions and criteria established in
that classification system.
For purposes of Section 131.10, this is
generally the case. Again, this Section of
the Federal regulation establishes two
requirements with respect to existing
use protection: (1) a prohibition against
removal of a designated use where that
use is determined to be an existing use,
and (2) a requirement that existing uses
be protected by State or Tribal
regulation. To ensure a workable
process, EPA interprets Section 131.10
as necessarily recognizing a linkage
between the existing use protection
provisions and the established State or
Tribal use classification system. This
interpretation of the regulatory
framework, however, also presumes a
responsibility on the part of a State or
Tribe to establish a classification system
that is sufficiently flexible and/or
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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
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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
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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)(l),
131.10(1) and 131.12(a)(l)). 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
CFR131.10(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 30l(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
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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] rejects 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
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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)(l)-(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 offish
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
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criteria described in the current
regulation (40 CFR 131.10(g)(l)-(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 andNon 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 131.10ft) 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
§ 131.10ft), 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,
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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) anytime
a State or Tribe seeks to designate a non
section 101 (a) (2) use. EPA, however,
believes that the analysis under either
provision is equivalent. Should the
current regulation be revised to clarify
that the UAA requirements apply to any
"downgrade" of a use and not just the
CWA Section 101 (a) (2) uses? Can any
needed clarification be achieved
through guidance or policy? EPA would
be interested in comments on factors to
be considered in evaluating the
attainability of non Section 101 (a) (2)
uses, such as water supply or
agricultural uses which generally take
place after the water is diverted from the
natural water body.
5. How should the water quality
standards regulation, guidance or policy
be modified to provide more specificity
on appropriate factors to consider in
developing a use attainability analysis?
6. In order to ensure the present
aquatic life use designation (or use
subcategory) matches the attainable
level of aquatic life use in a water body,
should the water quality standards
regulation, policy or guidance be
modified to clarify that a periodic
review of designated uses is required
where a State or Tribe has designated
only marginal or limited aquatic life
uses?
7. Are changes needed in the water
quality standards regulation, policy or
EPA guidance to address whether, and
under what circumstances, use
attainability analyses may be used to
justify a non-aquatic life use
classification, given the broad range of
aquatic communities that may exist?
d. Alternatives to "Downgrade" of the
Designated Use. As discussed above,
where a State or Tribe believes that a
particular designated use is not
attainable, States and Tribes have the
option of refining a water body's
designated use, for example by creating
subcategories of the use and describing
the use in more detail. A subcategory
can, and may need to be, water body-
specific if the State's or Tribe's use
classification system is not sufficiently
precise to accommodate the subcategory
of designated use for the water body in
question. States and Tribes also have the
option of removing the designated use
and replacing the removed use with a
new one that, under the regulation,
reflects attainable conditions in the
water body. Use removal and to a lesser
extent refinement are also commonly
referred to as use "downgrade." Both of
these options, refinement and removal
of the designated use, are not time-
limited. That is, the designated use that
results from exercising either of these
options becomes the new goal use of the
water body. In the following discussion,
three alternatives to use downgrade that
have been used by States are presented.
They are variances, temporary
standards, and ambient-based criteria.
These alternatives are less "draconian"
than use downgrading in the sense that
they can provide adjustments to
particular aspects of the standards—i.e.,
to the criteria for particular pollutants or
the criteria as applied to certain
dischargers—without changing the
designated use and the full suite of
criteria to protect the designated use.
EPA's current thinking is that often the
attainable condition of particular water
bodies is not well understood due to
uncertainty about expected results of
water quality improvement actions. In
such situations, EPA believes it may be
appropriate to implement water quality
protection actions, assess the results of
those actions, and implement additional
measures where necessary to continue
to improve water quality. EPA believes
that iterative assessment and
implementation in these types of
situations is probably the best way to
gain an understanding of the ultimate
attainable condition of the water body.
The mechanisms described below may
be well-suited to this situation because
they leave the designated use of the
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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 short-
term 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 source-
specific and are limited to five years or
the term of the NPDES permit
implementing the variance, whichever
is less. Variances may be granted for any
of the reasons listed at 40 CFR 131.10(g)
for which a use downgrade may be
considered. Like all revisions to State or
Tribal water quality standards, EPA
review and approval is required of any
variance granted by a State or Tribe and
variances may be renewed following the
same procedure originally used for
applying for a variance. Variances are
also subject to review as part of a State's
or Tribes triennial review of water
quality standards. Multiple discharger
variances (a variance that applies to
multiple point sources discharging to
the same water body) are also allowed
under the Great Lakes Guidance.
Variances granted under the Great Lakes
Guidance provisions may not jeopardize
the continued existence of any Federally
listed threatened or endangered species.
Further, under the Guidance, variances
are not available for new or
recommencing discharges. A
recommencing discharge is a source that
recommences discharge after
terminating operations. (40 CFR 122.2).
The Great Lakes Guidance was
developed in concert with many other
provisions addressing designated uses,
criteria, antidegradation and various
implementation policies for the Great
Lakes States and Tribes. Any evaluation
of the level of protection afforded water
quality under the Great Lakes Guidance
variance procedures should be made in
the context of the Great Lakes Guidance
as a whole. Similarly, the water quality
standards regulation is more than
simply the sum of its parts. Any
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approach to the implementation of
water quality standards variances must
be evaluated in the context of the entire
regulation.
EPA is considering whether
implementation of the variance
provision has been a useful component
of the water quality standards program,
and the overall program for protection
of water quality standards. In 1990, EPA
conducted a survey of State variances
and variance provisions (National
Assessment of State Variance
Procedures, Report, November 1990,
Office of Water Regulations and
Standards). This study showed that
variances had been granted on a very
limited basis. In fact, only 16 out of 57
States and Territories had granted
variances and some of those had done
so infrequently. EPA lacks detailed
information on why variances are not
being significantly utilized in most
States and Tribes. EPA is interested in
information regarding alternative
mechanisms that are being used by
States or Tribes in lieu of variances to
provide necessary short term and
temporary relief from applicable
criteria, and how any alternative
approaches address the feasibility of
ultimately attaining the criteria
associated with the underlying
designated use.
EPA is considering whether it would
be useful to include in the regulation
more explicit language reflecting current
EPA thinking and practice regarding
variances. As explained above, in order
to issue variances, States or Tribes must
include variances as part of the State's
or Tribe's water quality standards. EPA
believes, however, that in some
instances States may be misusing
variances. For example, over the years,
there have been instances where a State
has improperly granted a "variance"
from compliance with NPDES permit
limits, failing to include these variances
within the water quality standards
themselves. There has also been some
confusion regarding the necessity of
formal adoption of individual variances
into State and Tribal water quality
standards and whether the public
participation process associated with
NPDES permit issuance sufficiently
addresses those same needs for variance
adoption. EPA is also considering
whether to specify the degree to which
individual dischargers must document
the continued need for a variance before
the variance can be renewed at each
triennial review. EPA is considering
whether the water quality standards
regulation should provide more specific
guidelines on the use and content of
variance policies. EPA's current
thinking is that the regulation may need
to articulate certain aspects of variances
more explicitly, including:
—explicit reference to the criteria listed
in 40 CFR 131.10(g) as the criteria for
granting a variance;
—explicit statement that the granting of
a variance may not result in any loss
or impairment of an existing use;
—explicit statement that before a
variance can be granted, the applicant
must provide documentation that
treatment more advanced than that
required by sections 303(c)(2)(A) and
(B) of the CWA has been carefully
considered, and that alternative
effluent control strategies have been
evaluated and reasonable progress is
being made toward meeting the
underlying or original standards;
—explicit statement requiring the
highest level of water quality
achievable under the relaxed, interim
standard during the period of the
variance.
—explicit statment that a variance shall
not be granted if standards will be
attained by implementing cost-
effective and reasonable best
management practices for nonpoint
source control.
EPA believes that such a clarification
of its policy regarding variances could
serve to encourage proper use of
variances by States and Tribes while at
the same time reducing the possibility
of inappropriate use.
ii. Temporary Standards. As indicated
in the discussion on variances above,
the 1985 EPA Office of Water guidance
explained that it would be appropriate
to grant short-term variances to
individual dischargers based on any of
the six factors for removing a designated
use as listed at § 131.10(g). Of the six
use removal factors, the first five
address water quality and habitat
features of the water body as a whole.
These same factors are not, however,
ideally suited to making decisions about
the capabilities of individual
dischargers. For example, it is not
immediately clear how use removal
factor five, "physical conditions related
to natural features of a water body
* * * preclude attainment of a use",
could be applied to a decision about an
individual discharger. On the other
hand, the sixth factor, the substantial
and widespread economic and social
impact factor, is well suited to decisions
about individual dischargers which
explains why the economic hardship
test has been historically applied in
evaluating variances.
Several States have applied factors
similar to the first five use removal
factors in establishing variances for
entire water body segments or portions
of water body segments. These States
sometimes refer to these as "temporary
standards" or "temporary
modifications". This has been done
where the problems in a water body are
significant and widespread, involving
point and nonpoint sources of pollution
and their impacts on water quality and
habitat, that is waters significantly
impaired by multiple sources and not
just one or a few point sources. For
example, where historic mining
practices have severely impaired both
water quality and habitat throughout a
headwater basin, temporary standards
have been used. Rather than
downgrading these waters, the States
have applied temporary standards with
specific expiration dates for certain
pollutants affected by the historic
mining practices. In this way, the States
have maintained designated uses and
underlying criteria for other pollutants,
while recognizing that existing ambient
conditions for certain pollutants are not
correctable in the short-term. In such
cases, the temporary standards provide
a basis for permit limits in the shorter-
term. The temporary standards
approach is then used by these States as
the basis for remediation of damaged
water resources because the underlying
designated use and criteria to protect
that use actively drive water quality
improvements in the longer-term. EPA
Regional Offices have approved the use
of such temporary standards.
Temporary standards have been
implemented to date with little specific
Agency guidance on a water body
approach to variances. EPA is
considering whether the water quality
standards regulation or guidance should
specifically address temporary
standards. EPA's current thinking is that
if the regulation or Agency guidance
were to specifically address temporary
standards, such regulation or guidance
would need to address certain relevant
issues including: application criteria to
be used in deciding which waters might
qualify for temporary standards; a way
of identifying the existing, impaired
water quality conditions; a mechanism
for specifying the water quality needed
to fully attain the anticipated uses; and
a plan and driving mechanism aimed at
achieving needed water quality and
habitat improvements to fully support
compliance with the designated uses.
Where EPA has provided guidance to
individual States on use of State
temporary standards provisions, EPA
has advised that any temporary standard
should:
—be granted only where there is a
demonstration that one of the use
removal factors (40 CFR 131.10(g)(l)
through (6) has been satisfied;
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—be granted for a specific water body or
portion of a specific water body as
defined in State standards;
—identify and justify the numerical
criteria that will apply during the
existence of the temporary standard
and identify a "remediation plan"
aimed at compliance with the
underlying designated uses and
criteria;
—be established as close to the
underlying numerical criteria as is
possible;
—be reviewed every three years, at a
minimum, and extended only where
the conditions for granting the
temporary standard still apply;
—be in effect only for the specified term
of the temporary standard (or
extension thereof), and upon
expiration of the temporary standard,
the underlying numerical criteria
have full regulatory effect;
—not exempt any discharge to the water
body from compliance with
applicable technology or water
quality-based limits (based on the
temporary standards) or best
management practices;
—not apply to any new discharger to the
water body; and
—protect existing uses.
EPA is considering whether the use of
temporary standards represents a viable
alternative to use refinement or removal.
EPA is also considering whether the
regulation or guidance should explicitly
address use of temporary standards,
including specific limitations on the use
of temporary standards like those listed
above.
iii. Ambient-based Criteria. On a
limited basis, States have developed and
EPA has approved "ambient-based
criteria." These ambient-based criteria
have been developed for specific water
bodies and pollutants where such
criteria are shown to protect the
designated use and the existing use.
EPA believes that ambient-based criteria
can be preferable to a "downgrade" of
a use because the underlying designated
use is retained and because they may be
limited to only a small subset of
pollutants.
EPA has issued a policy
memorandum concerning one type of
ambient-based criteria, site-specific
criteria for aquatic life protection that
are based on natural conditions. (See
Memorandum from Tudor T. Davies,
Director Office of Science and
Technology, Subject: Establishing Site-
Specific Aquatic Life Criteria Equal to
Natural Background, November 5,
1997.) This policy states that States and
Tribes may establish site-specific
aquatic life criteria equal to natural
background conditions, but such criteria
must be scientifically defensible.
Additionally, the State's or Tribe's water
quality standards should contain or
provide specific authority for site-
specific criteria based on natural
background. States and Tribes should
also identify procedures for determining
natural background. EPA's current
policy also states that the State or Tribal
procedure for determining natural
background needs to be specific enough
to establish natural background
concentration accurately and
reproducibly. States and Tribes should
also provide for public notice and
comment on the provision, the
procedure and the site-specific
application of the procedure. The States
or Tribes will also need to document the
resulting site-specific criteria in its
water quality standards, including
specifying the water body segment the
site-specific criterion applies to. This
can be accomplished through adopting
the site-specific criteria into the State
and Tribal water quality standards, or,
alternatively by appending the site-
specific criteria to the water quality
standards.
In addition, a second approach that
some States have used and EPA has
approved is where the State or Tribe
could have met the test for downgrading
a use under 40 CFR 131.10(g)(3) i.e.,
"Human caused conditions or sources of
pollution prevent the attainment of the
use and cannot be remedied or would
cause more environmental damage to
correct than to leave in place", but
instead of downgrading the use, the
State or Tribe established certain criteria
based on ambient conditions where
those ambient conditions were shown to
be irreversible. In addition to assuring
that the existing use is protected, EPA
is interested in assuring that where the
ambient concentration of a pollutant
cannot be improved, i.e., it is
irreversible, that such condition be
maintained and not made worse. When
this occurs, EPA believes that for other
pollutants in the same water body for
which applicable criteria are being or
can be met, those criteria should remain
in place and not be made less protective
via a use downgrade. EPA's current
thinking is that the ambient-based
criteria need to be the best attainable. In
addition, EPA's current thinking is that
in order to establish ambient-based
criteria, the State or Tribe should
conduct an analysis equivalent to a use
attainability analysis for a downgrade
that should include a thorough
description of the biota that will be
protected via applicable water quality
criteria (both the unchanged pre-
existing criteria and the ambient-based
criteria).
EPA is interested in hearing
comments regarding these ambient-
based criteria mechanisms, and
specifically whether the regulation
should discuss these mechanisms more
specifically, and whether the regulation
should be more explicit about the
biological evaluation necessary to
describe the aquatic life use being
protected. EPA is also interested in
comments on whether the other relief
mechanisms based on the § 131.10 (g)
reasons, such as variances and
temporary standards, should also
require criteria which reflect the best
attainable conditions.
Request for Comments on Alternatives
to Downgrading a Designated Use
EPA seeks comment on the following
questions:
1. EPA requests comment on whether
variances, temporary standards and/or
ambient-based criteria can under certain
circumstances offer an environmentally
preferable alternative to refinement or
removal (downgrade) of the designated
use? Under what circumstances?
2. Does the current water quality
standards regulation or Agency
guidance or policy discourage persons
from seeking variances and/or
discourage States and Tribes from
granting variances (including temporary
standards)? What components of the
procedures are most problematic?
3. Reflecting EPA's current
interpretation of the regulation, should
the regulation make explicit that
individual variances and temporary
standards must be documented in a
State's or Tribe's water quality
standards before implementation as part
of NPDES permits?
4. Reflecting EPA's current
interpretation of the CWA and the
regulation, should the regulation
contain express reference to the factors
listed in 40 CFR 131.10(g) as the criteria
under which a variance (including
temporary standards) from water quality
standards will be allowed? Should any
of these factors be deleted? Should any
new factors be added?
5. Reflecting EPA's current
interpretation of the CWA and the
regulation regarding existing uses,
should the variance portion of the
regulation at 40 CFR 131.13 underscore
that the granting of a variance must not
result in any loss or impairment of an
existing use, for example by cross-
referencing the requirement at 40 CFR
131.12(a)(l) that existing uses must be
protected?
6. To reflect current practice and EPA
guidance, should the regulation be
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amended to require documentation by
either the applicant or the State or Tribe
demonstrating that treatment more
advanced than that required by sections
30 3 (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 chemical-
specific criteria, toxicity criteria,
biological criteria, sediment criteria and
physical criteria such as habitat and
flow balance. These criteria may be
expressed in either narrative or numeric
forms. Many of these criteria may be
developed to apply generally, or they
may be developed to apply to site-
specific situations. The CWA section
303(a)-(c) requires all States, and any
Tribe that has water quality program
authority, to evaluate the need for water
quality criteria to protect a designated
use and then adopt water quality criteria
(either EPA's or its own) sufficient to
protect uses designated for State or
Tribal waters. Economic and
technological factors (e.g., the ability of
analytical techniques to detect the
pollutant and treatment cost
considerations) may not be used to
justify adoption of criteria that do not
protect the designated use.
Narrative criteria are descriptions of
conditions necessary for the water body
to attain its designated use. Often
expressed as "free from" certain
characteristics, narrative criteria can be
the basis for controlling nuisance
conditions, e.g. floating debris or
objectionable deposits. Narrative criteria
are often the basis for limiting toxicity
in discharges. States and Tribes
establish narrative criteria where
numeric criteria cannot be established
or to supplement numeric criteria under
40CFR 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) (l) 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
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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)(l), the States and Tribes
are responsible for maintaining and
revising water quality standards.
Section 303(c)(l) requires States and
Tribes to review, and modify if
appropriate, their water quality
standards at least once every three
years. If EPA determines that a new or
revised standard is not consistent with
the requirements of the CWA, or EPA
determines that a revised standard is
necessary to meet the requirements of
the Act, Section 303(c)(4) authorizes
EPA to promulgate replacement water
quality standards. From time to time
EPA has chosen to undertake such
promulgations. In doing so, EPA
considers the most current available
scientific information, such as toxicity
data and exposure assumptions.
With a number of Federal
promulgations of water quality criteria
under section 303(c)(4) occurring over
time, or the publication of a new or
revised 304 (a) criteria guidance
document, the criteria value (s) in an
earlier Federal action may differ from
the value (s) in a subsequent Federal
action. This has led to some confusion
among the public with regard to what
EPA's current section 304 (a) water
quality criteria may be for a given
chemical at any given time, and, what
values EPA would promulgate for a
State or Tribe under section 303 (c).
Currently, EPA interprets the most
recent Federal action, whether taken
pursuant to 303(c) or 304(a), as
establishing the current section 304 (a)
criteria guidance. When EPA determines
that a Federal rule is necessary to
correct deficiencies in State criteria,
EPA looks to the most recent criteria
science, as articulated in either section
304 (a) criteria guidance or EPA's most
recent statement contained in a
proposed or final section 303(c) rule.
To date, the most recent Federal
recalculation of section 304 (a) criteria
occurred in the proposed California
Toxics Rule (CTR)(62 FR 42160), July
30, 1997. The proposed CTR was
undertaken pursuant to CWA section
303(c)(2)(B). In the Water Quality Act of
1987, Congress increased the emphasis
on numeric criteria for toxic pollutants
by enacting section 303(c)(2)(B). This
section requires all States and any Tribe
with water quality standards authority
to adopt ambient water quality criteria
for toxics (priority pollutants) for which
EPA has published criteria under
section 304(a), and for which the
discharge or presence could reasonably
be expected to interfere with the
designated use adopted by the State or
Tribe. In adopting such criteria, States
and Tribes must establish numerical
values based on: (1) 304 (a) criteria; (2)
304 (a) criteria modified to reflect site-
specific conditions; or, (3) other
scientifically defensible methods.
Again, EPA views the criteria program
as constantly evolving. Whenever new
or revised criteria are published,
whether under 304 (a) or a rule under
303(c), that action establishes the
Agency's most current section 304(a)
criteria guidance.
Whenever a State or Tribe revises its
water quality criteria EPA compares the
State criteria values and the basis of
their derivation to the criteria contained
in the most recent Federal action (either
303(c)(4) rule making or 304(a) criteria
guidance publication). Thus, there may
be cases where the applicable policies
and science have evolved such that EPA
would be comparing State or Tribe
adopted criteria values to Federal
criteria values other than those in older
rules or criteria guidance to determine
whether to approve the State's or
Tribes's criteria. This approach is
necessary to encourage State and Tribal
adoption of the most recent section
304 (a) criteria.
2. Ambient Water Quality Criteria to
Protect Aquatic Life
Aquatic life criteria are scientifically-
derived values, derived by States,
Tribes, or EPA, to protect aquatic life
from the deleterious effects of pollutants
in ambient water. States and Tribes may
use EPA's section 304(a) criteria
guidance in developing such criteria.
When developing numeric aquatic life
criteria, States and Tribes usually
express two concentrations; one that
protects against acute effects (effects
from short term exposure) and one that
protects against chronic effects (effects
from long term exposure). The short-
term concentration is expressed as a
Criterion Maximum Concentration
(CMC) and is the highest ambient
concentration of a toxicant to which
aquatic organisms may be exposed for a
short time period without causing an
unacceptable effect. The long-term
concentration is expressed as a Criterion
Continuous Concentration (CCC) and is
the highest ambient concentration of a
toxicant to which aquatic organisms can
be continuously exposed without
causing an unacceptable effect.
Water quality criteria to protect
aquatic life consist of three
components—magnitude, duration and
frequency. Magnitude refers to the
acceptable concentration of a pollutant.
Duration is the period of time (averaging
period) over which the ambient
concentration is averaged for
comparison with criteria concentrations.
Frequency is how often the criteria can
be exceeded to allow the aquatic
community sufficient time to recover
from excursions of aquatic life criteria
and to thrive after recovery.
The numerical aquatic life criteria are
expressed as short-term and long-term
concentrations in order that the criteria
more accurately reflect toxicological and
practical realities. The combination of a
Criterion Maximum Concentration
(CMC), over a one-hour acute duration
(a short-term average acute limit), and a
Criterion Continuous Concentration
(CCC), over a four-day chronic duration
(a long-term average chronic limit)
provide protection of aquatic life and its
uses. Recommended averaging periods
are kept relatively short because
excursions higher than the average can
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kill or cause substantial damage in short
periods.
The frequency limitations specify that
both the acute and chronic criteria may
be exceeded once in a three-year period
on the average. The recommended once
in a three-year period coupled with the
4-day chronic averaging period used for
the CCC approximately corresponds to
the historically used criterion
concentrations that occurs in a once-in-
ten year seven-day-average low flow
(7Q10). The once-in-three-year period
coupled with the one-hour acute
averaging period used for the CMC
approximately corresponds to the
historically used criterion concentration
that occurs in a once-in-ten year one-
day-average low flow (1Q10)
The method by which EPA derives
criteria is updated from time to time, to
incorporate advances in the science. To
overcome the limitations in the previous
approaches to duration and frequency, a
new risk assessment methodology is
being developed. EPA expects that the
new risk assessment methodology will
include an approach that will better
handle variable concentrations by use of
a kinetic-based toxicity model coupled
with a population response model. A
kinetic-based toxicity model considers
the speed at which effects appear in
different individuals and at different
concentrations. The kinetic-based model
allows prediction of the toxicity of any
series of time-variable concentrations. It
can predict how often effects would
occur, and what fraction of individuals
in the species would be affected.
To weigh the full impact that a
particular time series of concentrations
would have on the exposed population
of a species, an additional factor is being
considered: how long it takes to replace
those individuals lost due to the toxic
effects. Consideration of this involves
the use of a population model indicating
rates of recovery of different taxonomic
groups to stresses. The intent of this part
of the derivation is to allow the toxic
impact to be portrayed as the overall
average reduction in the number of
individuals in a species, both during
lethal or sublethal periods and during
recovery periods, accounting for both
partial lethality and partial recovery.
Request for public comment on Aquatic
Life Criteria
EPA requests comments on the
following question:
1. Prior to completion of all of the
aquatic life methodology revisions,
should EPA use the tools that have thus
far been developed (the kinetic model of
individual organism response to derive
the appropriate duration/averaging
period of the criterion or to evaluate
mixing zone alternatives and the
population effects model to derive the
allowable frequency of excursion above
the criterion) to re-examine and possibly
revise its recommendations on the
duration and frequency of criteria
excursions?
3. Site-Specific Criteria
EPA also provides guidance on how
States and Tribes may develop site-
specific numeric aquatic life criteria that
are either more or less stringent than the
criteria adopted by the State or Tribe
and that would normally apply to a
water body. Currently, national
guidance only has recommendations
and methods for establishing site-
specific water quality criteria for aquatic
life but guidance is under development
for deriving site-specific sediment
quality criteria as well.
The regulation currently specifies that
States and Tribes may adopt numeric
criteria based on published CWA
section 304(a) guidance, section 304(a)
guidance modified to reflect site-
specific conditions, or other
scientifically defensible methods. 40
CFR 131.11 (b). EPA recognizes that
States and Tribes may want to develop
numeric criteria that vary from CWA
section 304 (a) guidance for specific
waters (e.g., where chemical and
physical characteristics of local waters
alter the bioavailability and/or toxicity
of a pollutant; or when the species or
community actually present or desired
may be more or less sensitive than the
species or community represented by
the criteria database.) In such situations,
a site-specific criterion may be
appropriate. EPA has developed and
continues to develop guidance to assist
States and Tribes in the development of
site-specific criteria. (See Water Quality
Standards Handbook, Second Edition,
EPA 823-B-94-005a, August, 1994, pp
3-38 through 3-45 and documents cited
therein.)
Site-specific criteria are allowed by
regulation and must be submitted to
EPA for review and approval, as are any
changes to a WQS. The regulation at 40
CFR 131.11(b)(l) 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?
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2. Should the regulation or EPA
guidance specify the circumstances
under which site-specific criteria are
necessary?
3. Does EPA need to develop
guidance, policy, or clarify the
regulation regarding site-specific criteria
based on ambient conditions?
4. Should EPA explore broadening the
concept of site-specific criteria to
include watershed-specific or
ecosystem-specific criteria perhaps in
conjunction with a refined use
designation? If so, what type of
additional guidance or policy is
necessary to fully explain these
concepts and are any changes to the
regulation needed to enable and/or
facilitate use of watershed or ecosystem-
specific criteria?
4. Narrative Water Quality Criteria
Narrative criteria can be an effective
tool for controlling the discharge of
pollutants when numeric criteria are not
available. Narrative criteria, which have
become known as "free froms", were
first developed in 1968 and continue to
be used in State and Tribal water quality
standards. EPA guidance explains that
these "free froms" apply to all waters of
the United States at all flow conditions
(including ephemeral and intermittent
streams) (see Water Quality Standards
Handbook: Second Edition (EPA-823-
B-94-006, August 1994). Narrative Tree
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)(l)(v) and (vi) require narrative
criteria to be implemented through
NPDES permit limits. More specifically,
when the permitting authority
determines that a discharge causes, has
the reasonable potential to cause, or
contributes to an excursion above a
narrative criterion, the permit must,
under most circumstances, contain
effluent limits for whole effluent
toxicity. In addition, where the
permitting authority determines that a
specific pollutant for which the State or
Tribe has not adopted a chemical
criterion is in a discharge in an amount
that causes, has the reasonable potential
to cause, or contributes to an excursion
above a narrative criterion, the permit
must contain effluent limits for that
pollutant that are based on an
interpretation of the State's or Tribe's
narrative criterion. The regulation
provides three options for interpreting
the narrative criterion, and in addition,
EPA has provided guidance on this
requirement in both the Technical
Support Document for Water Quality-
Based Toxics Control and the Water
Quality Standards Handbook (both
Cited above). The guidance advises
States and Tribes to develop
implementation procedures that explain
the application and integration of all
mechanisms used by the State or Tribe
to ensure that narrative criteria are
attained (e.g., chemical-specific
requirements, whole effluent toxicity
requirements, and biological criteria,
where biological criteria programs have
been developed by the State or Tribe).
The rationale for this approach is that
comprehensive written procedures
facilitate implementation decisions,
reduce inconsistencies that can result in
different requirements for similar
situations, and promote effective and
sensible application of narrative toxics
criteria.
Although all States and Tribes have
some type of customary practice for
implementing narrative criteria, and
many States and Tribes have developed
implementation policies on narrowly
defined topics (e.g., to explain
application of whole effluent toxicity
testing requirements), very few, if any,
States and Tribes have developed
comprehensive written implementation
procedures that address all of the
narrative toxics criteria implementation
issues. The result may be inconsistent
application of narrative toxics
requirements within those States and
Tribes that have not developed such
procedures. In addition, the lack of
documented methods makes it difficult
for EPA to evaluate whether aquatic life
and or human health is being
adequately protected.
Request for Comments on Narrative
Criteria
EPA seeks public comment on the
following questions:
1. Should the regulation require
adoption of "free froms" and similar
criteria as being the minimum floor
allowable under the Clean Water Act.
2. Reflecting current practice, should
the regulation specify that States and
Tribes are required to adopt narrative
criteria for all waters?
3. At this time, EPA has limited
information about how States and
Tribes are implementing narrative
criteria with regard to nonpoint source
activities. How can narrative criteria
best be implemented in the nonpoint
source context and what might EPA do,
including modifying the regulation, to
enhance or further the use of narrative
criteria?
4. Does the existing requirement for
States and Tribes to identify methods
for implementing narrative toxics
criteria need to be clarified, and if so,
should EPA clarify the requirement with
additional guidance, or with revisions to
the regulation?
5. What minimum elements should be
included in an implementation method
for narrative toxics criteria? Should
implementation methods describe
application and integration of all of the
various mechanisms used to regulate
point sources, or should such methods
focus on only certain aspects of toxics
control (e.g., chemical-specific limits,
whole effluent toxicity limits)?
6. The current regulation requires the
State or Tribe to identify the method by
which the State or Tribe intends to
regulate point source discharges of toxic
pollutants on water quality limited
segments based on such narrative
criteria.
Should this narrative criteria
translation method apply only to point
source discharges of toxic pollutants on
water quality limited segments or to
both point and non-point sources?
7. Should the regulation more
explicitly require implementation
procedures for narrative criteria other
than toxics criteria? Should the
regulation include minimum
requirements for these implementation
procedures?
5. State or Tribe Derived Criteria
States and Tribes may develop their
own criteria although the water quality
standards regulation 40 CFR 131.11
provides that where such criteria are
less stringent than 304 (a) criteria
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guidance, the State or Tribe must
demonstrate the criteria are
scientifically defensible. Despite this
available flexibility, and for a variety of
reasons, most States and Tribes are
reluctant to derive their own criteria.
EPA is evaluating whether either
changes to the water quality standards
regulation or development of additional
guidance would assist State or Tribal
efforts to develop protective criteria. For
example, for many pollutants where
EPA criteria guidance has not been
issued, information is available which
would be useful in determining a
protective water quality criterion.
Sources of such information include
relevant scientific literature, EPA's
Integrated Risk Information System
(IRIS), EPA's Aquatic Toxicity Database
(AQUIRE), a database of high quality
aquatic life toxicity data (under
development), and other sources.
Request for Comment on State or Tribal
Derived Criteria
EPA requests comment on the
following question:
1. Would changes to the water quality
standards regulation or development of
additional guidance assist State or
Tribal efforts to derive criteria? What
changes or guidance would be most
helpful?
6. Water Quality Criteria for Priority
Pollutants
EPA has not revised the water quality
standards regulation to incorporate
CWA section 303(c) (2) (B) which was
added to the CWA in 1987. EPA has,
however, issued guidance on how States
and Tribes may comply with section
303(c)(2)(B). The "Guidance for State
Implementation of Water Quality
Standards for CWA Section
303(c)(2)(B):December, 1988" provides
three options for compliance:
Option 1 States and Tribes may adopt
Statewide or Reservation-wide numeric
chemical-specific criteria for all priority
toxic pollutants where EPA has issued
CWA section 304 (a) criteria guidance.
Option 2 States and Tribes may adopt
numeric chemical-specific criteria for
those stream segments where the State or
Tribe determines that the priority toxic
pollutants for which EPA has issued
CWA section 304 (a) criteria guidance are
present and can reasonably be expected
to interfere with designated uses.
Option 3 States or Tribes may adopt a
chemical-specific translator procedure
that can be used to develop numeric
criteria as needed.
The phrase "translator procedure" in
this context means a method for
translating a State's or Tribe's narrative
toxics criterion into chemical-specific,
numeric criteria sufficient to comply
with CWA section 303(c)(2)(B). As
discussed in EPA guidance ("Guidance
for State Implementation of Water
Quality Standards for CWA Section
303(c)(2)(B)," December 1988, Notice of
Availability at 54 FR 346, January 5,
1989), such translator procedures
generally identify the equations,
protocols, and data sources that are used
to translate narrative criteria into
derived chemical-specific criteria. Such
translator procedures are different from
the narrative criteria implementation
procedures required in 40 CFR
131.11 (a) (2) of the water quality
standards regulation in that such
implementation procedures must be
adopted into the State's or Tribe's
regulations and generally describe all
mechanisms that are used and
integrated to attain narrative criteria,
including chemical-specific, whole
effluent toxicity, and biological methods
(see the discussion of narrative criteria
implementation procedures in sub-
section (c)(6) above). EPA believes that
revisions to the water quality standards
regulation to incorporate the CWA
section 303(c)(2)(B) requirements would
enhance public understanding of EPA's
implementation of the provision.
EPA's guidance on CWA section
303(c)(2)(B) established a presumption
that any information indicating that
such pollutants are discharged or
present in surface waters (now or in the
future) may be considered sufficient
justification to require adoption or
derivation of numeric criteria. The
guidance made clear that the
requirement to adopt (or derive) criteria
applies not just to pollutants that are
already affecting surface waters, but also
to pollutants that have the potential to
affect surface waters in the future. The
rationale for this approach is that it is
important to have numeric criteria
applied to waters where current or
future activities may result in sources of
priority toxics that warrant regulatory
controls or other pollution abatement or
assessment activities. This
interpretation of section 303(c)(2)(B) is
now reflected in EPA guidance included
in the Technical Support Document
(TSD) for Water Quality-Based Toxics
Control (TSD) and the Water Quality
Standards Handbook (see page 30 in the
TSD).
In implementing CWA section
303(c)(2)(B), many States and Tribes
have adopted statewide or reservation-
wide criteria for all priority toxics
where EPA has issued CWA section
304(a) criteria guidance. Taking this
approach eliminates the need to
determine whether a "reasonable
expectation" for use interference exists
on a water body-by-water body basis,
and thus greatly simplifies the process
for establishing numeric criteria for
priority toxics. In other States and
Tribes, however, broad application of
numeric criteria for priority toxics has
not occurred, and the "reasonable
expectation" question has been a
significant implementation issue. EPA is
considering whether its existing
guidance on this issue is adequate to
support equitable decisions nationally.
Another issue stemming from CWA
section 303(c)(2)(B) implementation
concerns the State or Tribe option to
develop a "translator procedure" to
achieve compliance. In EPA's CWA
section 303(c)(2)(B) guidance, this
approach was described as Option 3.
The guidance intended to be used are
the 1980 Human Health Guidelines and
1985 Aquatic Life Guidelines. All of
which have been both peer reviewed
and publicly reviewed and thus meet
the requirements of "scientific
defensibility'' under 40 CFR 131.11.
Although EPA believes that adoption
of such chemical-specific translator
procedures potentially provide a State
or Tribe with a useful means of
establishing criteria, there are several
issues associated with the use of such
procedures. For example:
(1) It may be difficult for the public
to stay abreast of the current applicable
criteria where a State or Tribe does not
routinely publish an updated list of
State or Tribe criteria and provide wide
distribution.
(2) Public participation may occur
primarily on the details of the procedure
itself, rather than the pollutant-specific
criteria resulting from application of the
procedure.
(3) Without requirements to submit to
EPA for review and approval the
individual criteria generated using the
translator procedure, there could be a
tendency to not include such criteria in
the State's or Tribe's water quality
standards at the time they are generated.
A third issue that arises from State
and Tribal efforts to implement CWA
section 303 (c) (2) (B) concerns the
provision for priority toxic pollutants
that are not the subject of CWA section
304 (a) criteria guidance. Where such
numeric criteria guidance is not
available, and where necessary to
protect the designated uses, CWA
section 303(c)(2)(B) provides that when
a State or Tribe (1) reviews Water
Quality Standards or (2) revises or
adopts new standards pursuant to this
paragraph, States and Tribes are to
adopt criteria based on biological
monitoring or assessment methods.
When adopting criteria based on
biological monitoring or assessment
methods, States and Tribes currently
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have considerable latitude to devise an
approach to satisfy the requirement. For
example, States and Tribes may
establish ambient criteria for the
parameter toxicity. Alternatively, States
and Tribes could adopt narrative
biological criteria. Clearly, a variety of
approaches, representing a range of
resource commitments, may be used to
satisfy this requirement. All of these
approaches must meet the test of
"scientific defensibility" and be
consistent with the goals of the CWA.
Request for Comments on Water Quality
Criteria for Priority Pollutants
EPA seeks public comment on the
following questions:
1. With regard to compliance with
section CWA section 303 (c) (2) (B),
would it be better to include only a
general requirement, such as one which
repeats the language in the statute itself,
or should the regulation reflect EPA's
interpretation of the options to achieve
compliance with the provision?
2. Have problems or issues arisen in
the implementation of CWA section
303(c) (2) (B) that may need to be
addressed by changes in the regulation
or revised EPA guidance?
3. What factors should be considered
in determining whether a "reasonable
expectation" for use interference exists?
How has the "reasonable expectation"
threshold decision been interpreted and
addressed by the States or Tribes? Does
EPA need to clarify when a "reasonable
expectation" for use interference exists,
and if so, should the Agency clarify the
requirement by issuing additional
guidance, by issuing regulatory
requirements, or a combination of the
two approaches?
4. Where a State or Tribe adopts a
chemical-specific translator procedure
for derivation of numeric criteria, what
process should the State or Tribe follow
to ensure that notice of State derived
criteria is provided to the public?
5. Should EPA require States or Tribes
using translator procedures to publish
an updated list of criteria for all water
bodies?
6. Should EPA revise the regulation to
explicitly require that, where a
translator procedure is used to derive
criteria, public participation is required
for each individual criterion, even
where an opportunity for public
participation was previously provided
when the procedure itself was adopted?
7. Should submission of each
criterion derived using translator
mechanisms for review and approval or
disapproval be a requirement, even
where EPA previously reviewed and
approved the procedure itself? If so,
should implementation of derived
criteria (e.g., in NPDES permit renewal
and development) proceed even where
EPA has not yet issued an approval/
disapproval decision?
8. Does this statutory provision need
to be further clarified and interpreted by
the Agency? Should changes to the
water quality standards regulation or
Agency guidance be pursued?
7. Criteria for Non-Priority Pollutants
with Toxic Effects
Over the years, an issue which has
periodically arisen, particularly for non-
priority pollutants, has been the proper
approach to identifying the
circumstances for which adoption of
numeric criteria is required. Currently,
the regulation does not elaborate on
how this question should be addressed;
it only provides the general mandate to
adopt criteria "sufficient to protect
uses."
EPA's current thinking is that the
regulation should probably be modified
to further specify the circumstances
under which numeric criteria for non-
priority pollutants must be adopted.
One approach would be to model the
requirements for non-priority pollutants
after the requirements included in CWA
section 303(c)(2)(B) for priority
pollutants. That is, for non-priority
pollutants where EPA has issued criteria
guidance, the regulation could require
adoption of numeric chemical-specific
criteria where the discharge or presence
of the pollutant can reasonably be
expected to interfere with designated
uses. EPA could define "reasonable
expectation" broadly to support
adoption of criteria before new
pollution sources are proposed, or more
narrowly for non-priority pollutants,
limiting such a requirement for
adoption of criteria to only those water
bodies and pollutants where uses are
already being interfered with, or where
pollution sources now exist or are
certain to occur in the near future.
Establishing Such a requirement would
encourage development of criteria for
commonly-discharged and highly toxic
pollutants like ammonia and chlorine
that are currently not considered
priority pollutants under section 307(a)
of the CWA.
Strengthening the requirements for
adoption of criteria for non-priority
pollutants would address a concern of
some that many of the CWA section
307(a) priority pollutants are no longer
an appropriate focal point for State,
Tribe and EPA toxic control efforts (e.g.,
some of the pesticides included on that
list are no longer in widespread use).
Request for Comments on Criteria for
Non-Priority Pollutants With Toxic
Effects
EPA seeks public comment on the
following questions:
1. For what specific pollutants and
under what circumstances should
adoption of criteria for non-priority
pollutants be required by regulation?
2. Should EPA amend the water
quality standards regulation or issue
additional guidance to clarify when
adoption of numeric chemical-specific
criteria for non priority pollutants is
necessary to "protect designated uses"?
3. Should EPA require States or Tribes
to adopt narrative criteria and a
narrative criteria translation method for
both 307(a) and other pollutants which
elicit toxic effects on organisms?
8. Criteria Where Data or Guidance is
Limited
A key issue facing States and Tribes
seeking to develop aquatic life and
human health criteria concerns the data
requirements necessary to support
derivation of a criterion. (In developing
national CWA section 304 (a) criteria
guidance, EPA has established
minimum data requirements.) When
sufficient, acceptable data are not
available, however, many States and
Tribes have resorted to adoption of
lowest observed effect levels (LOELs) as
criteria in order to ensure that some
level of protection is in place. LOELs are
based on the lowest observed
concentration of a chemical at which a
statistically significant adverse effect
was observed in an aquatic test
organism. However, EPA would counsel
against adoption of water quality criteria
based on LOELs alone because they may
not ensure protection of aquatic life uses
since: (1) they represent effect
concentrations, and (2) there may be
significant limitations in the database
upon which they are supported.
Thus, if this approach is used, States
and Tribes are encouraged to use safety
factors to approximate better a
protective water quality level. The
particular safety factor employed
generally depends on the amount and
quality of data concerning the LOEL.
EPA has approved this approach in
particular instances because criteria
based on such LOELs provide more
protection than no criteria at all.
A better approach to developing
values with sparse data was developed
and promulgated by EPA as part of the
Water Quality Guidance for the Great
Lakes System (Great Lakes Guidance).
Under that Guidance's Tier II procedure,
States and Tribes derive values to
interpret the narrative criteria for
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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)(l) 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
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United States, Volume 1: National
Sediment Inventory," Office of Science
and Technology, September 1997, EPA-
823-R-97-006.) The contaminants of
interest are those that preferentially
partition to sediments, become
sequestered, and remain bioavailable to
the aquatic community. SQC are
intended to protect against chronic
effects to benthic organisms resulting
from sediment contamination. The
development and implementation of
SQC is intended primarily to enable
development of pollutant-specific State
standards and NPDES permit limits
needed for implementation of a more
effective source control program. In
addition, SQC will be useful in other
programs, such as developing clean-up
levels for sediment remediation
activities and in evaluating sediments
dredged from the Nation's waterways.
Sediment quality criteria have been
proposed for five non-ionic organic
compounds: acenapthene, dieldrin,
endrin, fluoranthene, and
phenanthrene. See, Technical Basis for
Deriving Sediment Quality Criteria for
Nonionic Organic Contaminants for the
Protection of Benthic Organisms by
Using Equilibrium Partitioning (EPA-
822-R-93-011); Acenapthene (EPA-
822-R-93-013); Dieldrin (EPA-822-R-
93-015); Endrin (EPA-822-R-93-016);
Fluoranthene (EPA-822-R-93-012);
Phenanthrene (EPA-822-R-93-014). In
addition to non-ionic organic
compounds, the Agency also is working
to develop SQC for metals. After
considering public comments, EPA
intends to publish final SQC dieldrin
and aldrin in final form. The proposed
criteria for acenapthene, fluoranthene,
and phenanthrene will not go final;
instead, EPA plans to propose a total
PAH sediment criterion. In addition to
its work on SQC, the Agency also is
working to develop standardized
methods for performing chronic
sediment bioassay tests.
The EPA Science Advisory Board
subcommittee reviewing SQC for non-
ionic organics concluded that: "these
criteria not be used as stand-alone, pass-
fail values for all applications." (EPA-
SAB-EPEC-93-002). EPA is developing
a users manual to provide guidance on
use of SQC in a regulatory context to
ensure consistency with that
recommendation. The guidance would
recommend that SQC be used in
conjunction with chronic sediment
bioassay tests in determining
compliance with State standards, such
as in interpreting the narrative criterion
of no toxics in toxic amounts. Such an
approach is currently being developed
in more detail, and the users guidance
will be made available to the public for
comment prior to being finalized.
Request for Comment on Sediment
Quality Criteria
EPA seeks public comment on the
following questions:
1. Should the current regulation be
revised to specifically address sediment
quality criteria, and if so, what should
such revisions address?
2. What chemicals or classes of
compounds should receive priority for
development of SQC?
11. Biological Criteria
Biological Integrity, Assessments and
Criteria '
The Clean Water Act directs EPA to
work with States and Tribes to restore
and maintain the biological integrity of
the Nation's surface waters (CWA
101 (a), 303, 518(e)). Biological integrity
is defined as a balanced, integrated,
adaptive community of organisms
having a species composition, diversity,
and functional organization comparable
to that of the natural habitat of a region
(Karr and Dudley, EPA-440/5-90-004,
1981). Biological integrity does not
necessarily represent an aquatic system
untouched by human influence, but
does represent one that is balanced,
adaptive and reflects natural
evolutionary processes. Designated uses
and criteria to protect those uses in
State and Tribal water quality standards
programs provide the means to achieve
biological integrity.
To more fully protect aquatic
resources and provide more
comprehensive assessments of aquatic
life use attainment, it is EPA's policy
that States and Tribes should designate
aquatic life uses for their waters that
appropriately address biological
integrity and adopt biological criteria
necessary to protect those uses (EPA-
823-B-93-002, Office of Water
Memorandum to EPA Regions, Policy
on Bioassessment and Biological
Criteria, 1991). Designated uses to
support aquatic life can cover a broad
range, or continuum, of biological
conditions with some waters being
closer to the ideal of biological integrity
than others. The attainable levels of
biological integrity for any water is a
State and/or Tribal determination
involving public participation.
For example, the State of Maine used
the water quality classification law to
establish the minimum standards for
three levels of biological integrity. These
levels correspond to the water quality
classification system and are
increasingly restrictive, proceeding from
the minimum state standard, Class C, to
Class A, the most protective standard.
These refinements serve to explicitly
specify the designated aquatic life uses
that apply to each classification
category. Class C requires that the
structure and function of the biological
community be maintained and provides
for the support of all indigenous fish
species. The intermediate standard of
Class B requires that there be no
detrimental changes to the aquatic
community, that all indigenous species
are supported and that habitat be
unimpaired. The Class A standard
requires that aquatic life be "as
naturally occurs" and habitat be
characterized as "natural." Within Class
A, there is even a subset, Class AA, that
further specifies "free-flowing" habitat.
Waters with the Class AA designation
are protected from any additional
discharge or alteration. Under this
system, attainment of the aquatic life
classification standards for a given
water body is evaluated using numeric
biological criteria that were statistically
derived from a statewide database. The
numeric biological criteria are slated to
go to rule-making in 1998.
Biological assessments are used to
evaluate the condition of a water body
using direct measurements of the
resident biota in surface waters.
Biological assessments integrate the
cumulative impacts of chemical,
physical, and biological stressors on
aquatic life. Biological criteria, derived
from biological assessment information,
can be used to define State and Tribal
water quality goals for aquatic life by
directly characterizing the desired
biological condition for an aquatic life
use designation. Biological criteria are
narrative descriptions or numerical
values that describe the reference
condition of the aquatic biota inhabiting
waters of a specific designated aquatic
life use (EPA-440/5-90-004). Biological
criteria are based on integrated
measures, or indices, of the
composition, diversity, and functional
organization of a reference aquatic
community. The reference condition
describes the attainable biological
conditions for water body segments
with common characteristics within the
same biogeographic region. In summary,
biological criteria provide a direct
measure of the desired condition of the
aquatic biota. This capability serves a
dual purpose—goal setting and
environmental impact analysis.
Biological assessments are then
conducted to evaluate if a water body is
attaining its designated aquatic life use.
Biological criteria can play an
important role in water quality
programs and when properly
implemented, complement and support
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other methods and criteria, such as
chemical water quality criteria and
whole effluent toxicity criteria. The
latter are measures, or indicators, of
environmental stress and exposure
whereas the biological assessments and
criteria measure the cumulative effects
of stressors on the aquatic community,
whether chemical, physical or biological
stressors, singly or in combination. A
water quality program that employs the
full array of methods and criteria will
develop the information needed for
more accurate assessment of impairment
and effective resource management.
The linkage of biological effects,
stressor identification and exposure
assessment is particularly important
when there are multiple stressors
impacting a water body, especially
when a watershed management
approach is taken, or where wet weather
flows are a major source of impairment
in the water body. A comprehensive
water quality program with biological,
chemical, toxicity, and physical
components will enable States and
Tribes to make better decisions and
focus limited resources to maximize
environmental gain. A critical issue
facing EPA's National Water Program is
the manner and extent to which
biological assessments and criteria
should be incorporated into water
quality programs to transition to a more
comprehensive water quality control
program that will better identify
impairments and track improvements.
This includes integrating biological
assessments and criteria into use
designations and attainability analyses,
watershed management strategies and
source control requirements.
Biological criteria typically include
measures of the types, abundance, and
condition of aquatic plants and animals,
providing information on the status and
function of the aquatic community in
response to the cumulative impact of
both chemical and nonchemical
stressors. For example, Ohio uses a
multi metric approach to develop
numeric biological criteria for two
different assemblages: benthic macro
invertebrates (bottom dwelling insects,
etc.) and fish (Yoder, 1995). Biological
indices have been derived that integrate
measurable structural and functional
characteristics of the in-stream fish and
macro invertebrate communities which
help assess the health of the
community. Structural characteristics
are based on measures of biological
community structure such as diversity
or taxa richness (e.g. total number of
taxonomic groups) and the
representation of specific taxonomic
groups (e.g. number of mayfly or
caddisfly taxonomic groups) within the
community. Functional characteristics
include measures of biological function
such as feeding strategy (e.g. percent
carnivores, omnivores), environmental
tolerance (e.g. number of intolerant and
tolerant species), and disease symptoms
(e.g. percent diseased species and
anomalies, including deformities,
eroded fins, lesions and external tumors
in fish).
The Ohio biological criteria were
developed based on ecoregional
reference conditions and provide a
quantitative biological description of the
State's designated aquatic life uses for
warm water rivers and streams,
including exceptional, general, modified
and limited warm water habitat. The
description and derivation of the
indices and ecoregions are contained in
the "Biological Criteria for the
Protection of Aquatic Life: Volume II.
Users Manual for Biological Field
Assessment of Ohio Surface Waters"
cited in Ohio's Water Quality Standards.
Ohio uses biological criteria to support
all aspects of its water quality
management program (Yoder, 1995).
Ohio's approach is another example of
how a State can adopt biologically-
based refined designated aquatic life
uses and biological criteria consistent
with EPA's policy.
Application of Biological Assessments
and Criteria in State and Tribal Water
Programs
Biological assessments and criteria
can be an important component of State
and Tribal watershed management
programs by assisting in prioritization
and targeting of actions, setting
restoration goals and performance
standards, and documenting results. For
example, North Carolina has adopted
narrative biological criteria into its
water quality standards regulation that
references standardized methods for
data collection and analysis for fish and
macro invertebrate communities.
Specific biological indices, metrics, or
numeric criteria are not included in the
water quality standards regulation.
However, by citing the standardized
methods in the State's water quality
standards, North Carolina established a
mechanism for consistent, quantitative
translation of the narrative biological
criteria. Under the State's five year
basin-wide management program,
benthic macro invertebrate and fish
community data are presented in
individual basin-wide assessment
reports. Macroinvertebrate and fish
community surveys, special studies, and
other water quality sampling activities
are conducted in the second and third
years of the cycle to provide information
for assessing status and trends through
the basin. Water quality management
plans are being developed for all of the
State's major river basins on five year
cycles.
Biological assessments and criteria
can fulfill several assessment functions
within the NPDES permitting process.
In conjunction with pollutant
concentration and toxicity data,
biological assessments can be used to
detect previously undetected chemical
water quality problems and to evaluate
the effectiveness of control actions.
Biological findings of use impairment
can trigger the necessary technical
investigations which can identify the
source or sources of impairment and
determine appropriate corrective
measures through point or nonpoint
source controls as appropriate. The
State of Maine uses biological
assessments and criteria to evaluate the
effectiveness of controls and to inform
the permit review process. Aquatic life
criteria are specified in the water quality
classification law and attainment is
assessed using quantitative data and a
multi variate statistical model. Findings
of biological impairment trigger
management intervention to identify
possible causes. Permits have been
modified and enforcement actions
initiated to address biological impacts.
Alternatively, favorable biological
findings have been used in a tiered
approach to re-direct limited agency and
permittee resources to more urgent
concerns.
In Maryland, investigators use
bioassessments as an integral part of the
Rapid Stream Assessment Technique
(RSAT) to conduct watershed-wide
stream quality reconnaissance, rapid
screening of general storm water BMP
performance and for elucidating general
watershed land use—stream quality
relationships (Galli, J., 1997). In
Michigan, biological assessments have
been used in the Wayne County Rouge
River National Wet Weather
Demonstration Project to identify
impacts and to guide decision-makers
and the public in evaluating options for
preventing, reducing and minimizing
pollution loading impacts on the river
under a watershed approach to wet
weather pollution management (Cave,
1997).
Biological assessments and criteria
can be useful in evaluating highly
variable or diffuse sources of pollution
such as storm water runoff. These types
of point source pollution do not lend
themselves well to traditional chemical
water quality monitoring and a
biological assessment of their
cumulative impact may effectively
evaluate these discharges and the
success of control actions.
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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
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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
StressorTden tifica tion
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
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criteria, should it require a narrative
only, or a combination of both narrative
and numeric criteria as described in the
draft implementation guidance (e.g
quantitatively-based biological criteria)?
What should EPA promulgate if a State
or Tribe fails to adopt biological criteria
in its water quality standards?
3. If EPA were to explicitly require
biological criteria, what is a reasonable
time frame for State or Tribal adoption?
4. What are practical, effective
approaches to identify and evaluate
potential stressors and sources of
impairment when a water body fails
biological criteria?
5. In what ways can biological criteria
and biological assessments be used to
effectively manage known stressors or
sources of impairment, including urban
and rural runoff?
12. Wildlife Criteria
Wildlife criteria are designed to
protect mammals and birds from
adverse impacts from pollutants due to
consumption of food or water from a
water body. A wildlife criteria
methodology applicable to the Great
Lakes Basin and a few wildlife criteria
were published as part of the Great
Lakes Guidance. EPA does not have an
active wildlife criteria guidance
program at this time but it is a potential
emerging criteria program. The wildlife
criteria that EPA promulgated in the
Great Lakes Guidance are for the
following four chemicals: DDT (and
metabolites), mercury, PCBs, and dioxin
(2,3,7,8-TCDD).
Request for Comment on Wildlife
Criteria
EPA requests comment on the
following question:
1. Does the regulation need to be
clarified to specifically address the
development of wildlife criteria
guidance for the protection of aquatic
dependent wildlife?
13. Physical Criteria
Physical criteria is a concept that
takes into account the physical
attributes of the aquatic environment,
such as quality of habitat and
hydrologic balance. Commenters on the
draft ANPRM identified physical habitat
and hydrologic balance criteria as
additional important forms of criteria
that should be discussed in the ANPRM.
EPA agrees that physical habitat
parameters, including flow, are
important and often overlooked
parameters that influence and at some
sites control whether or not an aquatic
life use is or will be attained. For
example, research referenced by
Schueler (see Schueler, T. The
Importance of Imperviousness.
Watershed Protection Techniques, Fall
1994) suggests that in many small urban
streams substantial loadings from
municipal separate storm sewer systems
are severely degrading the aquatic
habitat. The authors suggest that the
primary cause of this habitat
impairment is the high volume and
velocity of the storm water flows into
this type of stream. The high flows
exceed the peaks in the natural flow
regime of these streams and as a result
stream bank erosion, turbidity and
siltation occur and the local habitat is
degraded. Further habitat destruction in
larger downstream receiving waters
often results from the physical
deterioration of the upstream urban
systems. For example, some recent
studies have shown that in some lakes
the biggest source of silt and sediment
deposition into the lake is actually from
the eroded material that comes directly
out of the stream bed and stream banks
that are scoured out during elevated wet
weather peak discharges and extended
hydrographs. This can lead to
eutrophication, increased turbidity,
decreased light penetration, submerged
aquatic vegetation (SAV) loss, spawning
bed smothering, and shellfish habitat
damage.
Studies of this phenomenon suggest
that until these man-made flow regimes
are better managed and the resulting
stresses to physical habitat corrected, no
amount of control of pollutants is likely
to restore the aquatic ecosystem to a
level more closely resembling a natural
state.
The character of natural waters is
obviously affected by wet weather
events. Flowing waters, especially, can
change dramatically with the seasons
and in response to specific precipitation
events. Seasonal and event driven
changes in flows, sediment loads,
temperature, etc. are common and
natural processes which are integral to
the maintenance of natural waters and
their aquatic communities. Human-
caused changes to the landscape,
however, have altered these natural
processes, and for many waters, the
altered flows and the contamination
now associated with wet weather
discharges (discharges that occur in
whole or in part as the result of wet
weather events) present significant
environmental problems. Although
these problems are generally well
recognized, they have been difficult to
address effectively precisely because of
their magnitude and variable nature.
The CWA's objectives include the
protection and restoration of the
physical integrity of our nation's waters.
Scientific experts agree that overall
physical habitat loss is the single biggest
factor in the loss of aquatic species.
Physical habitat damage and loss to the
nation's waters includes: (1) Wetlands
losses; (2) the denuding of stream banks
through unwise forestry, farming,
mining, and urbanization; (3) the
embedding of stream bottoms with fine-
grained silt from poorly designed and
managed farm and construction sites; (4)
the damming of river systems; (5) the
channelization and/or concrete lining of
rivers and streams; (6) the obliteration of
ephemeral and first-order streams and
springs during urbanization and; (7) the
widening and deepening of stream
channels due to high-velocity urban
storm flows.
All seven of these phenomena are
common forms of aquatic habitat
damage and loss, and yet there is little
national guidance to address the
physical parameters that contribute to
these impacts. In addition, EPA does not
have a clear picture of how often
physical habitat parameters, including
flow are used by States and Tribes to
assess, manage, and/or regulate
activities that damage habitat. Some
commenters on the draft asserted that
water quality criteria guidance is
needed to address these forms of habitat
loss, to create threshold values to
protect designated uses and to provide
measuring tools for monitoring
watershed and water body health. EPA
agrees that further investigation of the
role of physical habitat parameters,
including hydrologic balance, in water
quality standards programs is necessary.
EPA is considering the relative
importance of such criteria guidance as
compared to other forms of criteria
guidance such as ambient water quality
criteria, sediment criteria and biological
criteria; and on the likelihood that
States and Tribes would develop and
implement such criteria if technical
guidance and supporting policy were
available. EPA is also interested in
identifying examples of where such
criteria guidance has already been used
as the basis for assessing, managing and
protecting water quality.
With respect to hydrologic balance,
EPA discusses the issue in the
antidegradation section of this ANPRM.
Some commenters on the draft ANPRM
suggested that maintaining hydrologic
balance in surface waters, though
important in the context of
antidegradation, is also important for
other aspects of water quality standards.
These commenters suggested that
hydrologic balance should be part of
basic water quality criteria guidance for
watershed and water body assessment
and for long-term urban storm water
abatement and prevention plans under
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the storm water NPDES program, as well
as for the traditional NPDES program.
EPA is further interested in issues
associated with hydrologic imbalances
created by various industries and land
operations, and the options for
researching and creating a set of
hydrologic balance criteria guidance.
These could include, for instance,
regional minimum stream flow criteria
on a seasonal or average monthly basis,
a groundwater-recharge criterion meant
to maintain adequate stream base flow,
and a peak-flood and bank full
discharge prevention criterion, perhaps
based on hydrologic regions of the
country.
Request for Comment on Physical
Criteria
EPA seeks comment on the following
questions:
1. Would it be useful to explicitly
identify physical criteria such as habitat
and hydrologic balance in 40 CFR 131
as a valid form of criteria that States and
Tribes can adopt in their water quality
standards?
2. Would EPA technical guidance on
physical criteria be useful to States and
Tribes? Is it necessary?
3. What are some examples of
physical criteria that are being used
today and what are they being used for?
4. What should be the principal uses
for physical criteria? Would these help
address pulsed or intermittent impacts,
such as those from urban and rural
runoff?
14. Human Health
Human health water quality criteria
are scientifically derived values
developed by States, Tribes, or EPA to
protect human health from the
deleterious effects of carcinogens and
noncarcinogenic toxicants. Human
health criteria take into account the
health effects from the consumption of
aquatic organisms and drinking water.
Human health criteria are based on the
potential of carcinogens and
noncarcinogenic toxicants to cause
adverse impacts to human health. When
adopting criteria to protect human
health, a State or Tribe may use EPA's
Section 304 (a) criteria documents or
other information on factors to derive
human health criteria. However, if a
State or Tribe decides to adopt criteria
less stringent than recommended by
EPA, the State or Tribe must provide
documentation which supports that the
approach is based on sound scientific
rationale.
Changes to the Human Health Criteria
Methodology are anticipated for
proposal in the Federal Register in
1998. These changes to the 1980
ambient water quality criteria (AWQC)
derivation guidelines (45 FR 79347) are
intended to reflect the many significant
scientific advances that have occurred
during the past 17 years in such key
areas as cancer and noncancer risk
assessments, exposure assessments and
bioaccumulation. Comments on any of
the key area issues, as well as
implementation issues, are welcome
and should be made during the public
comment period following the
anticipated 1998 proposal.
The following discussion focuses on
three key policy-related issues,
including: choice of risk levels; fish
consumption assumptions and
environmental justice, and the use of
maximum contaminant levels.
a. Risk Levels. Criteria for specific
pollutants for the protection of human
health rely in part on risk levels
(incidence of cancer). Numeric criteria
for carcinogens are based on three inter-
related assumptions: exposure, cancer
potency, and risk level. Exposure
considerations are based on a wide
range of factors, including an estimate of
the rate of fish and drinking water
consumption, an estimate of the body
weight of an exposed individual, and an
estimate of the rate of a chemical's
relative tendency to bioaccumulate in
fish tissue as compared to the
surrounding water. Cancer potency
factors (ql *) 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 1Q-5, 1Q-6, and 1Q-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,
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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 non-
occupational exposures to chemicals
used as pesticides, and to aggregate risks
from chemicals that share a common
mechanism of toxicity. EPA's Office of
Pesticide Programs is in the process of
developing new policies in response to
the FQPA. EPA's Office of Water will
consider these policies when they are
completed.
b. Fish Consumption Assumptions.
EPA's recommended human health
criteria under CWA section 304 (a)
guidance are currently derived with a
fish consumption rate of 6.5 grams per
day (roughly one quarter ounce of fish
and shellfish). This value represents an
average based on market survey data
gathered in 1973-74, and reflects a
national average for all consumers and
nonconsumers of fish and shellfish from
estuarine and fresh waters. Again, EPA
intends to propose revisions to the
human health methodology for deriving
ambient water quality criteria, including
revisions of the fish consumption rate.
Some assumptions regarding fish
consumption and criteria policy are also
discussed in FR Vol. 61, No. 239, 65183
(December 11, 1996).
EPA recognizes that, while important,
the national fish consumption estimate
is one of many different parameters
used to set ambient water quality
criteria to protect human health and that
the interactions of these parameters
adds substantial complexity to the
methodology. However, because this
component is easily understood, it
receives the most attention from the
general public. Overall, EPA considers
its human health criteria methodologies
to be conservative and protective of
human health.
EPA also recognizes that there are
subpopulations that consume greater
quantities of fish and has considered
this as part of the human health
methodology for developing water
quality criteria. State and Tribal human
health criteria are often based on a risk
level of 10~5 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 offish (i.e., it is greater for
individuals consuming more fish than
the national average).
A similar rationale for the
protectiveness of a criterion may not
apply to non-carcinogenic pollutants
(i.e., RfD-based chemicals), where
significantly higher fish consumption
rates may (when combined with other
exposure sources) result in exposures
significantly exceeding the RfD.
Although there are safety factors
associated with an RfD, they are related
to uncertainties associated with the
toxicological evaluation, not with the
sources and levels of exposure.
Therefore, significantly higher intakes
may require more stringent criteria to
protect human health.
EPA is seeking ways to implement
Executive Order 12898 (February 16,
1994, 59 FR 7629) regarding
environmental justice to ensure that
water quality criteria are developed
taking into account populations such as
Native Americans and other minorities,
as well as other subsistence fishers. This
would include working with the
scientific community and the public to
improve EPA's health assessments and
risk assessments and incorporate
relevant issues into its policies and
guidance. This also includes
mechanisms for public participation
(e.g., meetings) for the purposes of fact-
finding, receiving comments, and
conducting inquiries concerning
environmental justice.
Relevant to water quality standards,
EPA recognizes the need to address
issues regarding different fish
consumption patterns among
subsistence, minority populations. EPA
acknowledges that these groups may
consume a greater quantity of fish than
the national average. In addition, these
groups have asserted that States and
Tribes should be required to take a more
aggressive role in protecting them.
Guidance for Assessing Chemical
Contaminated Data for Use in Fish
Advisories (Vol. 1-IV, USEPA, 1993 and
1994) notes that fish and shellfish
consumption rates vary greatly for
sections of the U.S. population (e.g., by
gender, race, age, cultural and
recreational activity, and income levels).
Given the wide variations in
consumption patterns, it would not
seem to be possible for States and Tribes
to provide the same level of protection
from contaminated fish for all
consumers. EPA believes criteria should
ensure adequate protection of all
significant populations and
subpopulations from reasonable risks.
States and Tribes are encouraged to
consider local surveys when selecting
fish consumption rates to protect their
populations since the national average
value may not be indicative of local
consumption habits. In its Water
Quality Guidance for the Great Lakes
System (60 FR 15366, March 23, 1995),
EPA included a Great Lakes-specific fish
consumption rate of 15 grams per day.
This rate was based on several fish
consumption surveys from the Great
Lakes (see 60 FR 15366 at 15374, March
23, 1995.) EPA has also published for
external peer review "Draft Guidance
for Conducting Fish and Wildlife
Consumption Surveys." (U.S. EPA
1997).
States and Tribes could be encouraged
to modify criteria on a site-specific basis
to provide additional protection
appropriate for highly exposed
subpopulations. That is, where high-end
consumers would not be adequately
protected by criteria derived using the
default fish intake assumption, the State
or Tribe may modify this assumption to
provide appropriate additional
protection. Again, such a
recommendation was made in the Great
Lakes Guidance. This preference will
also be stated in the proposed revisions
to the human health methodology for
deriving ambient water quality criteria.
c. Maximum Contaminant Levels.
Under the Safe Drinking Water Act
(SDWA), EPA develops chemical-
specific numeric values for use in
protecting public drinking water
supplies. They are maximum
contaminant level goals (MCLGs) and
maximum contaminant levels (MCLs). A
MCLG is a non-enforceable
concentration of a drinking water
contaminant that is protective of
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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 (RID) 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
(RID) 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 RID. To
develop CWA human health criteria for
noncarcinogens, the 1980 CWA National
Guidelines recommended taking non-
fish dietary sources and inhalation into
account. However, data on these other
sources were generally not available.
Therefore, it was typically assumed that
an individual's total exposure to a
chemical came solely from drinking
water from the water body and
consumption of fish and shellfish living
in the water body. Also, CWA criteria
are based on a prediction of exposure
from fish and shellfish using a
bioconcentration factor (BCF) to
estimate the bioconcentration of the
individual chemical, and a fish/shellfish
consumption rate. To date, under the
current MCLG methodology, BCFs have
not been used in the exposure estimates
and fish/shellfish consumption rates
have been only marginally accounted
for (e.g., via general FDA dietary
estimate or conservative default
assumption).
Because of the differences in the
approach to exposure and the basis of
toxicity values, the health-based
drinking water goal (MCLG) is
sometimes more stringent than the CWA
human health criterion (304 (a)
criterion). However, the opposite is
sometimes true. An example of the
former is 1,4-dichlorobenzene, for
which both the MCL and MCLG are 75
ug/L and the 304 (a) criterion (for
protection of human health from the
exposures of drinking water and
consuming contaminated fish) is 400
ug/L. In this case, the MCLG was
developed based on an assumption that
20% of the total exposure is from
drinking water (the RSC factor applied
to this noncarcinogen), whereas the
CWA criterion effectively assumes that
non-water exposure is negligible.
Additional sources of difference
between the two values are: (1) the BCF/
BAF for 1,4-dichlorobenzene is low and
thus does not make the 304 (a) value
significantly lower; (2) the MCLG was
derived from an RID of 0.1 mg/kg/day,
while the 304 (a) criterion utilized an
Acceptable Daily Intake (ADI, now
replaced by the use of RfDs) of 0.013
mg/kg/day; and, (3) the MCLG included
a safety factor of 10,000, whereas the
water quality criterion included a safety
factor of only 1,000.
In contrast, for noncarcinogens where
the BCF/BAF is high, the CWA criteria
may be roughly equivalent or more
stringent than the health-based drinking
water levels because of the considerable
exposure via fish/shellfish consumption
that is assumed in deriving the CWA
criteria. As with the previous example,
the difference may be compounded if
the toxicological values have a different
basis. An example is endrin, for which
the MCL and MCLG are 2 ug/L and the
CWA section 304 (a) human health
criterion (again, for protection from the
exposures of drinking water and
consuming contaminated fish) is 0.76
ug/L. In this case, the drinking water
level is, again, developed based on the
RSC assumption of 20%, whereas the
CWA criterion assumes that non-water
exposure is negligible. However, the
BCF/BAF for endrin is quite high
(3,970) and drives the 304(a) value
significantly lower. Furthermore, the
MCLG was derived from an RfD of 3.0
x ID-4 mg/kg/day, while the CWA
criterion utilized an ADI of 1.0 x 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
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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 (33/1 OOmL and 35/1 OOmL
respectively) and E. Coli for fresh waters
(126/1 OOmL). 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,
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beach advisories and closures, and
health risks associated with swimming
in contaminated water.
While the Enterococci and E. Coli
indicators and criteria guidance are
satisfactory for determining risks from
acute gastrointestinal disease they are
not necessarily acceptable for
determining risks from enteric viruses
nor from pathogenic enteric protozoa
such as Giardia and Crypto Sporidium
since these pathogens are much more
resistant environmentally and
experience different treatment
effectiveness. EPA is currently
evaluating how it may develop human
health criteria for protection from these
organisms.
EPA may conduct additional research
to develop indicator methods for non-
enteric pathogens that cause skin,
respiratory, eye, ear, and throat
infections that are not detected by the
current indicator methods. EPA also
intends to examine the phenomenon of
regrowth of the current indicators on
soil and vegetation in tropical areas, and
if deemed necessary add indicator
development studies to replace the
current indicators in tropical
recreational areas. Further studies are
proposed to examine rapid chemical
indicators of fecal pollution to see if a
tiered sampling protocol can be
established for recreational water
monitoring. Also, EPA plans to examine
the development of improved
monitoring strategies that States, Tribes
and local authorities could use to assess
the true impact of pollution during wet
weather events. Finally, EPA will
examine various computer models that
could be used to predict microbial
pollution from storm water events in
watersheds and at recreational areas.
These models would be validated by
microbiological monitoring.
Request for Public Comment on
Microbiological Criteria
EPA seeks public comment on the
following questions:
1. Where and how is it best to conduct
future programs to determine the safety
of recreational waters?
2. What communication strategies
would best inform the public about
pathogen exposures?
3. What guidance should EPA provide
to States, Tribes, and local governments
on how to conduct beach monitoring
activities?
16. Nutrient Criteria
In the National Water Quality
Inventory 1994 Report to Congress,
nutrients (nitrogen and phosphorous)
are cited as one of the leading causes of
water quality impairment in our
Nation's rivers, lakes and estuaries.
While nutrients are essential to the
health of aquatic ecosystems, excessive
nutrient loadings can result in the
growth of aquatic weeds and algae,
leading to oxygen depletion, increased
fish and macro invertebrate mortality
and other water quality impairments. In
December 1995, EPA held a National
Nutrient Assessment Workshop with the
goal of developing a comprehensive
nutrient strategy which would provide
tools that can be used in assessing and
controlling nutrients in all types of
water bodies. Major conclusions from
that workshop were: (1) a single set of
national nutrient criteria is not a
realistic goal, and (2) nutrient criteria
need to be set on an ecoregional or
watershed basis. EPA has since been
developing a national nutrient strategy
in order to communicate the specific
approach and activities necessary to
meet the goals and major conclusions of
the National Nutrient Assessment
Workshop.
On February 14, 1998, the "Clean
Water Action Plan" was announced by
the Administrator of EPA and the
Secretary of Agriculture. The "Clean
Water Action Plan" is a blueprint for
restoring and protecting the Nation's
precious water resources. As part of this
Action Plan, EPA intends to identify the
major sources of nitrogen and
phosphorous in our waters and to
identify actions to address these
sources. In particular, EPA intends to
accelerate development of nutrient
criteria guidance for waters in every
geographic region in the country, so that
EPA and the States and Tribes can begin
implementing a criteria system for
nitrogen and phosphorous runoff for
lakes, rivers, and estuaries by the year
2000. EPA will assist States and Tribes
in adopting numeric water quality
criteria for nitrogen and phosphorous,
which EPA expects will take the form
either of State- or Tribe-derived criteria
where data is available, or criteria based
on EPA default ranges applicable to
their ecoregion(s). Where a State or
Tribe does not adopt appropriate
nutrient standards, EPA intends to begin
the process of promulgating nutrient
standards. To support meeting these
expectations, EPA anticipates the
following actions described below.
First, EPA intends to publish a
National Nutrient Strategy which will
present currently available tools for
assessing eutrophication, identify
important implementation issues related
to controlling eutrophication, and
provide the Agency's plan for
developing water body-type guidance
on nutrient over enrichment.
This national strategy will also
present EPA's expectations for action on
the part of States and Tribes, namely,
development of numeric nutrient
criteria and standards on a regional/
watershed basis. Second, by the end of
the year 2000, EPA expects to publish
the water body-type guidance
documents which would serve as "user
manuals" for assessing and controlling
nutrient over enrichment for specific
water body types: lakes and reservoirs,
rivers and streams, and estuarine and
coastal waters. These documents will
include techniques for assessing the
trophic state of a water body and a
methodology for developing region-
specific nutrient criteria. In each
document, EPA intends to provide
regional nutrient ranges for phosphorus
and nitrogen (and other parameters),
which EPA would expect States and
Tribes to use in setting nutrient criteria
in the absence of any criterion that has
been developed site-specifically. EPA
intends to use existing State and Tribal
projects and data, supplemented with
new regional case studies and
demonstration projects that are being
conducted to collect information in
data-limited areas of the country. An
important component in developing
default nutrient values is determining
the appropriate scale of application
(e.g., watershed, ecoregion, Northern
lakes/Southern lakes, etc.). Finally, in
order to promote the use of the water
body-specific guidance, and ensure the
development of nutrient criteria on a
watershed or ecoregional basis
nationwide, EPA will undertake several
activities, including: (1) training in EPA
regions and States, and Tribes, through
the use of Regional Technical
Assistance Centers; (2) appointing EPA
Regional Nutrient Coordinators who
will oversee the development and
implementation of nutrient criteria and
standards in each of the EPA Regions;
and (3) offering assistance grants which
will provide financial support to States
and Tribes in their efforts to assemble
existing data, including nutrient
endpoint data, and to establish nutrient
criteria either by watershed or
ecoregion, where sufficient data are
available.
Request for Comments on Nutrient
Criteria
EPA requests comment on the
following questions:
1. Should the regulation specifically
require States and Tribes to adopt and
implement numeric nutrient criteria?
2. What capabilities do States and
Tribes have right now for developing
and implementing water quality criteria
for nutrients?
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3. What are the institutional
impediments to collecting nutrient data
and developing nutrient standards, for
example, staff numbers and expertise
and financial resources?
4. Which States or Tribes are using an
ecoregion or watershed approach to
develop numeric nutrient standards
(EPA is aware of some States doing
this)? For those States and Tribes that
do not, on what scale do their nutrient
standards apply—statewide or by water
body type?
D. Antidegradation
1. Background
The Federal antidegradation policy
has its roots in the Water Quality Act of
1965 (Pub. L. 89-234), which stated in
its declaration of policy, "The purpose
of this Act is to enhance the quality and
value of our water resources and to
establish national policy for the
prevention, control, and abatement of
water pollution." Policy guidelines
established by the Department of the
Interior in 1966 for use in the approval
of States' water quality standards
contained additional direction on
antidegradation, stating that "In no case
will standards providing for less than
existing quality be acceptable" and
"The water quality standards proposed
by a state should provide for: . . . The
maintenance and protection of quality
and use or uses of waters now of a high
quality or of a quality suitable for
present and potential future uses."
Secretary of the Interior Udall further
defined the Federal policy on
antidegradation in 1968, when he said
that each State was to include a
statement similar to the following in
their water quality standards:
Waters whose existing quality is better
than the established standards as of the date
on which such standards become effective
will be maintained at their existing high
quality. These and other waters of a State
will not be lowered in water quality unless
and until it has been affirmatively
demonstrated to the State water pollution
control agency and the Department of the
Interior that such change is justifiable as a
result of necessary economic or social
development and will not interfere with or
become injurious to any assigned uses made
of, or presently possible in, such waters. This
will require that any industrial, public or
private project or development which would
constitute a new source of pollution or an
increased source of pollution to high quality
waters will be required, as part of the initial
project design, to provide the highest and
best degree of waste treatment available
under existing technology, and, since these
are also Federal standards, these waste
treatment requirements will be developed
cooperatively.
The Federal Water Pollution Control
Act Amendments of 1972 (Pub. L. 92-
500) continued to emphasize the
prevention of pollution and, in 1973,
EPA developed guidance for State water
quality standards under the
Amendments that essentially repeated
the 1968 statements of Secretary Udall.
In 1975, EPA promulgated regulations
at 40 CFR 130.17(e) that required the
States to develop an antidegradation
policy and implementation procedures.
The 1975 rule contained provisions that
are very similar to those in 40 CFR
131.12, and provided protection for
existing uses, high quality waters, high
quality waters that constituted an
outstanding National resource, and
waters impaired by thermal discharges.
EPA issued final rules on November 8,
1983 (48 FR 51400) that retained, with
certain changes, the 1975
antidegradation policy and incorporated
it into the regulations at 40 CFR 131.12.
The changes to the 1975 antidegradation
policy are discussed in the preamble to
the 1983 rulemaking (48 FR 51402-
51403), but they were generally
intended to clarify the policy with no
change in coverage or effect. An
exception to this was the change in the
provisions applicable to outstanding
National resource waters, which
eliminated the strict "no degradation"
requirement in favor of a limited
exception for activities that result in
temporary and short-term lowering of
water quality. The 1983 regulation (40
CFR 131.12(a)) provides that a State or
Tribe is to identify its method for
implementing the antidegradation
policy, i.e., decision measures for
assessing activities that may impact the
integrity of a water body.
The 1987 Water Quality Act
Amendments to the Clean Water Act
(CWA) explicitly incorporated reference
to antidegradation policies in section
303(d)(4)(B), which requires that such
antidegradation requirements be
satisfied prior to modifying certain
NPDES permits to include less stringent
effluent limitations (this concept is
referred to as antibacksliding).
On March 23, 1995, EPA published
the final Water Quality Guidance for the
Great Lakes System (the Great Lakes
Guidance). The Great Lakes Guidance
includes an antidegradation component
that is intended to work in conjunction
with the other components of the Great
Lakes Guidance to address the most
pressing threats to water quality in the
Great Lakes. In order to achieve this
end, the focus of the antidegradation
component is on decisions pertaining to
new or increased loadings of specified
bioaccumulative chemicals of concern
within the Great Lakes basin. For other
types of pollutants, States and Tribes are
required to comply with the existing
regulations at 40 CFR 131.12.
In the course of establishing a
framework for making decisions
regarding increased loadings of
bioaccumulative chemicals of concern,
the Great Lakes Guidance touches on a
number of issues. The Great Lakes
Guidance provides a procedure for
identifying high quality waters on a
pollutant-by-pollutant basis. The Great
Lakes Guidance also defines how a
significant lowering of water quality
will be identified for purposes of
determining whether or not an
antidegradation review is required.
Finally, the Great Lakes Guidance
includes implementation procedures
that describe how an antidegradation
review should be conducted. In all
cases, the antidegradation components
of the Great Lakes Guidance are tailored
to the control of bioaccumulative
chemicals of concern; other solutions
may be necessitated by environmental
threats faced elsewhere in the Nation.
EPA's current thinking is that on a
national scale, antidegradation is not
being used as effectively as it could be
and that a structured national debate on
antidegradation is key to improvement.
The debate needs to identify
deficiencies in antidegradation policy
and implementation provisions and
begin the process of strengthening
antidegradation as a meaningful
mechanism to attain and maintain water
quality standards. EPA invites
comments and suggestions on the three-
tiered approach currently in use and
described below, as well as possible
other approaches to more effectively
accomplish the intent of the
antidegradation requirements. As part of
the "Clean Water Action Plan"
announced on February 14, 1998 by the
Administrator of EPA and the Secretary
of Agriculture, EPA plans to develop
additional guidance on Antidegradation.
The discussion below articulates current
EPA thinking in several areas of
antidegradation. Elements of this
current EPA thinking will likely be
incorporated into the Antidegradation
guidance EPA develops under the
"Clean Water Action Plan."
2. General Description of
Antidegradation
An antidegradation policy performs
an essential function as part of the of
States' and Tribes' water quality
standards. Designated uses establish the
water quality goals for the water body,
water quality criteria define the
minimum conditions necessary to
achieve the goals and an
antidegradation policy specifies the
framework to be used in making
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decisions regarding changes in water
quality. The intent of an antidegradation
policy is to ensure that in all cases, at
a minimum, water quality necessary to
support existing uses is maintained (tier
1), that where water quality is better
than the minimum level necessary to
support protection and propagation of
fish, shellfish and wildlife, and
recreation in and on the water
("fishable/swimmable"), that water
quality is also maintained and protected
unless, through a public process, some
lowering of water quality is deemed to
be necessary to allow important
economic or social development to
occur (tier 2), and to identify water
bodies of exceptional recreational or
ecological significance and maintain
and protect water quality in such water
bodies (tier 3). Antidegradation plays a
critical role in allowing States and
Tribes to maintain and protect the finite
public resource of clean water and
ensure that decisions to allow
reductions in water quality are made in
a public manner and serve the public
good.
The watershed approach may be a
powerful tool to achieving
antidegradation goals (i.e., maintaining
the chemical, physical, and biological
integrity of the Nation's waters). Many
and varied uses are made of the Nation's
waters and in some cases, these uses
conflict. The ability of particular waters
to accommodate all uses is limited. High
quality surface waters are an important
and finite resource whose availability
affects the health, welfare, and
economic well-being of all the citizens
of the United States. When operating
properly, the antidegradation policies of
States and Tribes ensure that water
quality is conserved where possible and
lowered only when necessary, and that
those affected by the lowering of water
quality have a say in the final decision.
As a result, antidegradation policies are
well-suited to assist States, Tribes and
local communities in establishing and
achieving watershed goals. Sensitive or
highly valued water bodies can be
identified and protected from
degradation through outstanding
national resource water (ONRW) or
related designations. In other water
bodies, where water quality is better
than the minimum necessary to support
fish and aquatic life and recreation,
water quality should be maintained
unless there is a demonstrated need to
lower water quality. Consistent with the
watershed approach and community-
based environmental management,
States' and Tribes' antidegradation
policies and procedures can be a basis
for a systematic and accessible planning
process that protects against
development having negative impacts
on water quality. Additional authorities
exist at the local level beyond State,
Tribal and federal authorities which
may allow additional protections to be
put in place in accordance with the
watershed management plan.
The water quality standards
regulation requires each State and
authorized Tribe to adopt, as part of its
water quality standards, an
antidegradation policy consistent with
40 CFR 131.12 and identify
implementation methods for such a
policy. This antidegradation policy
provides a multi-level approach for the
protection of water quality and applies
to both point and non-point source
activities. The level of protection that is
provided to a specific segment depends
upon a number of factors (e.g., a key
determinant is whether existing water
quality is found to exceed levels
necessary to support "fishable/
swimmable" uses). Antidegradation
requirements are typically triggered
when an activity is proposed that may
have some effect on existing water
quality. Such activities are reviewed to
determine, based on the level of
antidegradation protection afforded to
the affected water body segment,
whether the proposed activity can be
authorized. "Antidegradation reviews"
under all three tiers of antidegradation
should be documented and subjected to
public review and comment (e.g., as part
of the public review of the water quality
certification, NPDES permit, or other
regulatory action).
Identifying the universe of activities
that trigger antidegradation
requirements is a fundamental and often
controversial issue because of the
number and variety of activities that can
affect water quality. Clearly, a wide
range of activities that affect water
quality may be subject to
antidegradation requirements, and
States and Tribes have considerable
flexibility in applying antidegradation
policies.
The federal antidegradation
requirements do not create, nor were
they intended to create, State or Tribal
regulatory authority over otherwise
unregulated activities. It is the position
of EPA that, at a minimum, States and
authorized Tribes must apply
antidegradation requirements to
activities that are "regulated" under
State, Tribal, or federal law (i.e., any
activity that requires a permit or a water
quality certification pursuant to State,
Tribal or federal law, such as CWA
§ 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
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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)(l) "tier 1"
Section 131.12 (a)(l) 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(1).
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)(l)) and must also be able to
identify the level of water quality that
is required to permit an existing use to
continue to occur. Section 131.3 defines
existing uses as, "those uses actually
attained in the water body on or after
November 28, 1975 * * *"
Traditionally, when establishing
designated uses, States and Tribes tend
to define uses in terms of broad classes,
such as warm water fishery or
secondary contact recreation. Inherent
in each of the broad use categories are
specific uses that may be affected by a
change in water quality. For example, a
warm water fishery designated use may
include the existing use of large mouth
bass fishery. Many people would be
upset if the warm water fishery
designated use was protected in such a
way as to allow a decline in the bass
population. The central question faced
by States and Tribes in determining
whether or not a proposed action will
impact existing uses is whether each
specific use within a use class must be
maintained (each individual type of
species), or whether only the use class
itself must be maintained (allow
changes in species composition, but
maintain a fishery). State and Tribal
interpretations of this requirement vary
considerably and are often tied to the
degree of precision the State or Tribe
achieves in defining designated uses.
Many States and some Tribes have
addressed these questions by using the
same degree of precision for both
designated and existing uses. EPA's
current thinking is that this is an
acceptable approach as long as the
State's or Tribe's designated uses and
criteria applicable to those uses are
adequate to ensure that existing uses are
maintained under the federal
antidegradation provisions. It would not
be acceptable, for example, for a state to
allow the loss of an existing natural cold
water community in favor of a warm
water community because both satisfy
the general use designation of "aquatic
life." Nor would it be acceptable to
allow shifts from existing pollution
intolerant communities to communities
that tolerate degraded conditions. The
advantage of this approach is that the
same criteria used to protect the
designated use can be assumed to also
protect the existing use. Under this
approach, however, the protection
afforded to existing uses is limited by
the degree of refinement associated with
the designated uses. States and Tribes
that have more specific designated uses
(i.e., including a number of use sub-
categories) can potentially provide more
protection by addressing more subtle
changes to the existing use. States and
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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. 40CFR 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-by-
water body approaches. States and
Tribes following the first approach
determine whether water quality is
better than applicable criteria for
specific pollutants that would be
affected by the proposed activity. Thus,
available assimilative capacity for any
given pollutant is always subject to tier
2 protection, regardless of whether the
criteria for other pollutants are satisfied.
Such determinations are made at the
time of the antidegradation review (i.e.,
as activities that may degrade water
quality are proposed). States and Tribes
following the second approach weigh a
variety of factors to judge a water body
segment's overall quality. Such
determinations may be made prior to
the antidegradation review (i.e., the
State or Tribe may assign "high quality"
designations in the State or Tribal
standards), or during the course of the
antidegradation review. Under this
water body-by-water body approach,
sometimes referred to as the
"designational" approach, assimilative
capacity for a given pollutant may not
be subject to tier 2 protection if, overall,
the segment is not deemed "high
quality."
There are advantages and
disadvantages to each approach. EPA's
current thinking is that neither
approach is clearly superior and that
either, when properly implemented, is
acceptable. EPA has approved both
approaches in State standards. Some
States and Tribes have found the
pollutant-by-pollutant approach to be
easier to implement because the need
for an overall assessment considering
various factors is avoided. Also,
decisions are driven strictly by water
column data (i.e., rather than judgments
concerning a segment's overall value or
quality) and thus may be less
susceptible to challenge. The pollutant-
by-pollutant approach may result in
more waters receiving some degree of
tier 2 protection because it would cover
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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-by-
water body approach preserves water
quality even if criteria for certain
pollutants are not attained or if criteria
for certain uses may be limited, such as
fish consumption. This approach also
allows for the high quality water
decision to be made in advance of the
antidegradation review (and included in
the water quality standards for the
segment), which may facilitate
implementation. A water body-by-water
body approach also allows States and
Tribes to focus limited resources on
protecting higher-value State or Tribal
waters. The water body-by-water body
approach can also distinguish between
high quality waters and high water
quality and preserve high quality waters
on the basis of physical and biological
attributes, rather than high water quality
attributes alone. However, the flexibility
of the water body-by-water body
approach is also its principal
disadvantage where a State or Tribe
does not develop inclusive qualification
criteria. For example, where a State's or
Tribe's implementation guidelines
define a narrow universe of waters,
many deserving high quality waters may
not receive tier 2 protection. Thus water
quality may actually decrease in the
waters not classified for tier 2 protection
without a public review of the
development decision. Also, a potential
problem can arise if the process of
identifying high quality waters becomes
so complicated, resource-intensive, and
data-intensive that the primary purpose
of tier 2 (i.e., seeking to maintain and
protect existing quality by identifying
whether there are reasonable less-
degrading or non-degrading alternatives)
is not adequately accomplished. In other
words, the limited resources available
for water quality protection could be
spent on the identification process at
the expense of analysis of the necessity
for degradation.
b. Tier 2 Implementation. The current
regulation provides a great deal of
flexibility to States and Tribes in
implementing tier 2 requirements. Some
States and Tribes devote little effort to
implementing their tier 2 requirements,
some States and Tribes apply tier 2
requirements in an inconsistent or
infrequent manner, and other States and
Tribes have active programs that
routinely and consistently implement
tier 2. In general, those States and Tribes
that actively implement their tier 2
requirements do so by conducting an
antidegradation review to determine
whether proposed activities that might
affect water quality may be authorized.
EPA's current sense is that the
antidegradation policy, in reality, has
little effect on decisions related to
surface water quality unless the State or
Tribe adopts an implementation
procedure and uses it. EPA currently
reviews all State and Tribal water
quality standards at the time of
adoption/revision to ensure they
establish a clear approach to
implementation. A brief discussion of a
number of the major implementation
issues is presented below.
i. Triggers for tier 2 Review. Although
not discussed in 40 CFR 131.12 of the
water quality standards regulation, State
and on occasion Tribal tier 2
implementation procedures often
include guidelines which are used to
determine when the water quality
degradation that will result from a
proposed activity is significant enough
to warrant further antidegradation
review. Where the degradation is not
significant, the antidegradation review
is typically terminated for that proposed
activity. The significance evaluation is
usually conducted on a pollutant-by-
pollutant basis, even where a water
body-by-water body approach is used to
identify high quality waters, and
significant degradation for any one
pollutant triggers further review for that
pollutant.
Applying antidegradation
requirements only to activities that will
result in significant degradation is a
useful approach that allows States and
Tribes to focus limited resources where
they may result in the greatest
environmental protection. However,
there is a great deal of variation in how
States and Tribes define significant
degradation. Significance tests range
from simple to complex, involve
qualitative or quantitative measures or
both, and may vary depending upon the
type of pollutant (e.g., the approach may
be different for highly toxic or
bioaccumulative pollutants). In some
cases, States have also created
categorical exemptions from tier 2
review (e.g., they have exempted entire
categories of activities from
anti(degradation 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
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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 130.2Q).
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
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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 (Dol) 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 Dol.
ONRWs are designated by the State or
Tribe in their water quality standards.
Wild and scenic rivers are given their
designation by Congress or the
Department of Interior pursuant to the
Federal Wild and Scenic Rivers Act.
The main purpose of the Wild and
Scenic Rivers Act is to keep waters free-
flowing. The main purpose of an ONRW
designation is to maintain and protect
high quality waters that constitute
outstanding resources due, for example,
to their exceptional recreational or
ecological significance, which can
include free-flowing water. EPA does
not see any conflict between these two
programs.
b. Tier 3 Implementation. EPA in
chapter 4 of the Water Quality
Standards Handbook interprets the
"water quality to be maintained and
protected" provision of the regulation as
requiring no new or increased
discharges to ONRWs and no new or
increased discharge to tributaries to
ONRWs that would result in lower
water quality in the ONRWs. The only
exception is for short-term and
temporary changes. In contrast, some
States, Tribes, and EPA Regions have
interpreted this provision to allow new
discharges as long as the water quality
is either maintained or improved.
Alternatively, some States, Tribes and
Regions have interpreted water quality
in terms of the characteristics for which
the water body was selected to be an
ONRW and have strictly maintained
those characteristics while allowing
other characteristics to become
degraded. EPA has also allowed a
proposed activity that will result in a
new or expanded source where the
applicant agrees to implement or
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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 2l/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 2l/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 2l/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 2l/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 2l/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 2Vz 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
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minimally acceptable content or the
approaches EPA considers to be not
approvable or inconsistent with the
CWA. Further, most regulatory agencies,
as well as the regulated community, are
most concerned with what is required
rather than what is recommended.
Policy or guidance is not binding
whereas regulation is. Guidance is better
designed to provide detailed
descriptions of the variety of technically
sound implementation approaches and
their underlying scientific basis;
regulation provides the clearest
direction regarding required minimal
program content and identification of
those components of the program where
flexibility is allowed.
EPA is considering an expansion of
the section of the regulation addressing
general policies to provide clear,
detailed and specific direction to States
and Tribes on the development and
content of mixing zone policies and
implementation procedures. EPA's
current thinking is that greater
specificity within this portion of the
regulation may be needed to clarify the
minimum necessary elements of State
and Tribal mixing zone policy and
implementation procedures. EPA's
current thinking is that this area of the
regulation needs to articulate a clear
level of national consistency in mixing
zone implementation that results in a
consistent level of protection across the
country and at the same time, where
State and Tribal flexibility is not only
encouraged, but possibly essential to
program efficiency and accuracy.
2. EPA Policy and Guidance on Mixing
Zones
The concept of mixing zones as a
regulatory tool to address the
incomplete mixing of wastewater
discharges in receiving waters has been
embraced by both EPA and its
predecessor agencies as part of a larger
regulatory effort to ensure that point
source discharges of wastes do not
impair beneficial uses. EPA interprets
the CWA as allowing the use of mixing
zones as long as the provisions
addressing toxicity at section 101 (a) (3)
are met and the designated uses of the
water body as a whole are protected.
One court has considered the
application of a mixing zone in a
discharge permit and upheld EPA's use
of a limited mixing zone (See Hercules
v. EPA, 598 F.2d 91 (D.C. Cir. 1978)).
The concept of a mixing zone is covered
by a series of guidance documents
issued by EPA and its predecessor
agencies (see, for example: Water
Quality Criteria (Green Book), Federal
Water Pollution Control Administration,
1968, pp. 29-31; Water Quality Criteria
1972 (Blue Book), EPA, March 1973, pp.
112-115, 231-232, 403-457; Guidelines
for Developing or Revising Water
Quality Standards, January 1973;
Chapter 5—Guidelines for State and
Areawide Water Quality Management
Program Development, November, 1976;
Allocated Impact Zones for Areas of
Non-Compliance, EPA Region 1,
October 1986; The Water Quality
Standards Handbook, August, 1994,
pp.5-1 to 5-11; Technical Support
Document for Water Quality-based
Toxics Control (TSD), March, 1991, pp.
31-34, 56-60, 69-89).
Many definitions of mixing zones
have been offered, differing primarily by
perspective (i.e., engineering,
hydrological, ecological, regulatory) and
their application. From a hydrological/
engineering perspective, mixing zones
can be defined based upon the
recognition of incomplete mixing of an
effluent with its receiving water (e.g.,
"that area or volume of dilution water
necessary to reduce contaminant
concentrations to some acceptable level
or to a totally mixed condition").
Biologically, mixing zones can be
defined based on the premise that
surface water quality criteria can be
exceeded under limited circumstances
without causing unacceptable toxicity
or, more broadly, impairment of the
designated beneficial uses (e.g., "the
area contiguous to a discharge where
receiving water quality is not required
to meet water quality criteria nor other
requirements applicable to the receiving
water").
EPA's policy on the use of mixing
zones has evolved since its early
recognition within general water quality
guidance, primarily in association with
the institution and evolution of the
NPDES permit program (e.g., the TSD).
Initially, guidance emphasized the need
to ensure that the biological integrity of
the aquatic community in the receiving
stream was protected and that such
determinations must be based on site-
specific evaluations. In the late 1980's
EPA and authorized NPDES States
began increasing the development and
issuance of water quality-based effluent
limits. With this increase, came a
demand for widely applicable national
guidance to support those programs.
EPA and States, in essence, needed
wasteload allocation and water quality-
based permit limit derivation methods
that were relatively simple to use and
could be implemented with little site-
specific data. EPA met this demand by
issuing revised guidance (the TSD and
Handbook, cited above, are examples)
and by accepting a wide range of State
mixing zone practices. As a result,
mixing zone provisions have become
less prescriptive than earlier guidance
that envisioned data rich, site-specific
studies, and more reliant on often
cursory evaluations, general mixing
assumptions, and best professional
judgement.
EPA's current policy addresses
mixing zones as allocated impact zones
(AIZs) where certain numeric water
quality criteria may be exceeded as long
as: there is no lethality to organisms
passing through the mixing zone, there
are no significant risks to human health,
and the designated and existing uses of
the water body are not impaired as a
result. These AIZs or mixing zones, if
disproportionately large, could
unacceptably impact the integrity of the
aquatic ecosystem and have
unanticipated ecological consequences
on the water body as a whole resulting
in impairment of the designated or
existing uses. Therefore, EPA's policy
has emphasized a holistic approach to
mixing zone regulation which considers
location, size, shape, outfall design and
in-zone quality. Mixing zone guidance
produced by EPA since 1972 has
consistently emphasized the need to
protect both nonmotile benthic and
sessile organisms in the mixing zone as
well as swimming and drifting
organisms (Water Quality Criteria 1972).
States and Tribes, however, have
focused primarily, if not exclusively, on
the protection of swimming and drifting
organisms and the need to provide
"zones of passage" within waters with
mixing zones. In its dependence upon
conditions protective of swimming and
drifting organisms to define mixing
zones, this approach results in an
incomplete implementation of the
original concept supporting mixing
zones. As originally designed, EPA's
mixing zone policy provided for the
prevention of lethality to swimming and
drifting organisms by limiting the size of
the mixing zone and to nonmotile
organisms by limiting the placement or
location of mixing zones.
Although existing EPA guidance on
the implementation of mixing zones
(cited above) is quite detailed, at
present, the regulation itself simply
provides that States and Tribes may
adopt, as part of their water quality
standards, mixing zone policies and that
such policies are subject to EPA review
and approval (40 CFR 131.13). In
addition, EPA may separately review
individual State and, once approved to
administer NPDES, Tribal mixing zone
determinations as part of the wasteload
allocation and NPDES permit review
process, outside the standards adoption
and review process to ensure
appropriate implementation of the
State's mixing zone policy.
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EPA is considering expanding the
current provisions at 40 CFR 131.13
addressing State and Tribal
development of mixing zone policies
within their water quality standards
program to address the content and
design of those policies.
3. State and Tribal Mixing Zone Policies
While there are advantages to the
more flexible general approach adopted
in the late 1980's, the generality of the
current regulation has led to some
uncertainty as to what constitutes an
approvable mixing zone policy. Because
the regulation lacks detailed
requirements concerning EPA's
standards of review of State and Tribal
mixing zone provisions, EPA is
considering changing the language
regarding State and Tribal adoption of
mixing zone policies to address
specifically the content of such policies.
EPA's current thinking is that greater
specificity would provide for increased
public participation in State, Tribal and
Federal decision-making; a clearer
understanding by the State, Tribe and
public of what EPA considers an
approvable mixing zone policy; a
reduction in the number of NPDES
permit appeals and objections based on
differing interpretations of a State or
Tribal mixing zone policy; and a more
consistent review of State and Tribal
submissions by EPA itself.
Fundamental to any such policy, EPA
is considering requiring States and
Tribes to indicate explicitly in their
water quality standards whether or not
they allow mixing zones for each of the
various uses designated for a given
water body. Such provisions could
address mixing zones applied to either
acute or chronic aquatic life and other
water quality criteria (e.g., public water
supply, livestock watering, wildlife
protection, etc.). Under this approach, if
the State or Tribe does not explicitly
authorize mixing zones, then no mixing
zones would be allowed in State or
Tribal waters, and all applicable criteria
would have to be met at the end-of-pipe.
(Memorandum from Robert Perciasepe,
Assistant Administrator for Water to
Water Program Directors, Regions I-X,
Subject: EPA Guidance on Application
of State Mixing Zone Policies in EPA-
Issued NPDES Permits, August 6, 1996).
Alternatively, States and Tribes could
determine that such prohibitions would
be applied to only a subset of uses or
pollutants rather than across all use
categories and pollutants. Some States
or Tribes have used this approach to
prohibit mixing zones in their highest
use classes (e.g., class AA), while
allowing mixing zones in more highly
impacted watersheds (e.g., class C or D
waters).
States and Tribes could also be
required to specify the conditions under
which mixing zones are allowed in each
site-specific application and the
limitations to those applications (e.g.,
size, shape, length, placement, etc.). In
addition, States and Tribes could be
required to identify any circumstances,
pollutants, locations or conditions for
which the use of mixing zones is
prohibited. States and Tribes could
specify circumstances where only
chronic mixing zones would be allowed
(i.e., no acute mixing zone or zone-of-
initial dilution) and circumstances
where acute and/or chronic mixing
zones would be prohibited. Current EPA
guidance, for example, recommends
States and Tribes consider prohibition
of mixing zones when bioaccumulative
pollutants are present in the discharge
or where an effluent is known to attract
biota. Other circumstances where
mixing zone prohibitions or location
restrictions might be appropriate
include areas used by aquatic life for
breeding or feeding, locations of
shellfish beds, locations of critical
habitat for threatened and endangered
species, across tributary mouths,
shallows, near shore areas and in areas
of critical habitat.
This change would clarify in the
regulation the State and Tribal general
authority to provide mixing zones, the
scope of that authority, and the site-
specific factors evaluated by States and
Tribes when deciding whether a mixing
zone is authorized in each individual
case. EPA is considering making this
potential clarification to the regulation,
its implications, and how mixing zone
policies can be designed to better
support and foster a watershed
management framework.
4. Mixing Zone Requirements
Some States and Tribes that have
adopted mixing zone provisions within
their water quality standards have not
specified mixing zone requirements
(e.g., water quality within mixing zones,
the allowable size of mixing zones, etc.)
under their mixing zone policies. EPA is
therefore considering including as
regulatory requirements certain
specifications derived from EPA's
guidance on mixing zones. Regarding
policy content, EPA might revise the
regulation to require that State and
Tribal mixing zone policies address a
minimum number of elements. Those
required elements might include
provisions that: identify conditions and
circumstances (e.g., particular locations)
when mixing zones are not permitted;
identify any pollutants or classes of
pollutants for which mixing zones are
prohibited; identify the mechanisms to
be used to ensure that mixing zones do
not impinge on ecologically or
recreationally sensitive areas; identify
the mechanisms to be used to determine
complete and incomplete mixing of
effluent and receiving water; identify
conditions when a mixing analysis is
required; identify default design flows
for implementing criteria; identify
maximum allowable mixing zone size
and configuration, as well as how
mixing zones dimensions are
determined; specify what water quality
conditions must be met within mixing
zones; state whether zones of initial
dilution are allowed; and state whether
there are special conditions established
for bioaccumulative pollutants.
Identification in the regulation of
minimum elements of State or Tribal
mixing zones procedures would
establish the basis for EPA review and
approval of State and Tribal mixing
zone provisions. It would also facilitate
the review of individual mixing zone
determinations made under the
wasteload allocation/permit approval
process by EPA, other agencies and the
public. This would not significantly
change EPA's guidance or current
approach to mixing zone policies.
Rather, it would clarify and codify the
basis by which EPA will review and
approve or disapprove State and Tribal
mixing zone policies and their site-
specific implementation through NPDES
permits.
As discussed previously, EPA's
mixing zone guidance is premised
fundamentally on the prevention of
lethality within the mixing zone and
siting such that areas of critical habitat
are avoided, resulting in the protection
of designated uses. One aspect of this
guidance is that, for aquatic life uses,
water quality within the mixing zone
should be such that, at a specified
concentration of a contaminant (i.e.,
magnitude), any "swimming or drifting"
organism would not remain in the
mixing zone long enough to receive an
exposure that is sufficiently long (i.e.,
duration) to cause lethality. If the
combination of the concentration of a
given pollutant or the combined effect
of multiple pollutants (e.g., whole
effluent toxicity) in a discharge and the
duration of exposure to that
concentration are low enough, there is
no lethality within the mixing zone, and
the criteria (magnitude and duration
components together) are met.
This approach, however, only
provides protection in situations in
which water column organisms pass in
and out of the mixing zone. This
interpretation does not adequately
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protect stationary or sessile organisms
within the mixing zone; organisms that
remain within the mixing zone for
extended periods because the mixing
zone extends into feeding or breeding
areas or critical habitat (e.g., tributary
mouths, shallows, shoreline habitat in
large, fast-flowing rivers); critical habitat
areas for endangered or threatened
species; or instances where mixing zone
conditions attract organisms. EPA's
mixing zone policy and guidance
address those instances where the
provisions protecting swimming and
drifting organisms are not adequate to
protect nonmotile benthic and sessile
organisms or critical habitat areas by
limiting the location, size and shape of
mixing zones. In some instances, this
policy has been implemented in a
fragmented manner. In such instances,
these latter restrictions to mixing zone
placement are inadequately addressed.
EPA always has discretion to object to,
and take over if necessary, permits that
provide site-specific mixing zones in
cases where such mixing zones would
fail to protect all aspects of designated
uses. However, oversight of individual
permits is not an efficient approach to
resolving program-level issues. To
clarify the meaning of its policy and
ensure a more complete implementation
of protective mixing zone provisions,
EPA is considering changes to the
regulation.
EPA could require that State and
Tribal mixing zone policies specifically
identify prohibitions (where
appropriate) or limit mixing zones
where necessary to protect existing or
designated uses. Some States and Tribes
already include prohibitions against the
use of mixing zones where they could
intrude upon public drinking water
supply intakes or public swimming
beaches, or where mixing zones prove to
be attractive to aquatic life or wildlife
(e.g., water temperature). EPA might
require that State and Tribal mixing
zone provisions specifically address
instances such as these where
restrictions on mixing zones are
appropriate. Additionally, EPA is
considering requiring that State and
Tribal water quality standards include a
description of the State's or Tribe's
methodology for specifying the location,
geographic boundaries, size, shape and
in-zone quality of mixing zones.
EPA could also clarify its current
policy that an approvable mixing zone
methodology must be scientifically
defensible and ensure the protection of
designated uses in the water body as a
whole. This would require that the
methodology, at a minimum, be
sufficiently precise to support
consistent regulatory actions (e.g., an
NPDES permit). EPA is considering this
change to ensure that State and Tribal
mixing zones do not adversely affect the
integrity of State and Tribal waters and
to address inconsistent allocation of
mixing zones from site-to-site. Under
this approach, for example, when a
State or Tribe assumes that either
complete or incomplete mixing occurs,
the State's or Tribe's implementation
procedure could require the analyses
supporting the mix assumption to be
documented in the record (e.g., permit
fact sheet). EPA is considering the need
for additional language in the water
quality standards regulation to clarify
the essential elements of State or Tribal
mixing zone provisions and,
alternatively, whether such language
would be better established in guidance.
EPA's current thinking is that a certain
amount of professional judgement is
necessary in making site-specific mixing
zone determinations and that
clarifications to the regulation regarding
the minimum mixing zone policies and
implementation procedures should not
preclude such flexibility. However, the
policy and implementation procedures
should be clarified so that the
guidelines and framework for making
site-specific mixing zone determinations
are clear to everyone.
5. Mixing Analyses
The above discussion focuses on
establishing State and Tribal mixing
zone policies and procedures. The
following discussion addresses the
application of such procedures in
individual permitting decisions.
Where point source discharges mix in
a slow or "incomplete" manner with
receiving waters and the State or Tribe
has authority to provide a mixing zone,
EPA guidance recommends that a
mixing zone analysis be incorporated
into the derivation of water quality-
based effluent limits (WQBELs) in
NPDES permits. The mixing zone
analysis should demonstrate
compliance with State or Tribal mixing
zone requirements (e.g., size, shape,
location and in-zone quality) that are
included in the water quality standards.
Providing a mixing zone in incomplete-
mix situations acknowledges the mixing
behavior of the discharge and limits
excursions above criteria to a specified
zone. Where a discharge mixes with the
receiving water in a rapid and
"complete" manner, by definition a
mixing zone analysis is not needed and
an evaluation of the assimilative
capacity of the receiving water and a
dilution allowance based on stream
design flow conditions specified in the
State or Tribal water quality standards
is often incorporated into the derivation
of WQBELs.
Presently, all State-issued NPDES
permits are reviewable by EPA. EPA
may object to individual permits and
assume authority to issue such permits.
When EPA is the permit issuing
authority, it must follow the applicable
State or Tribal water quality standards
and ensure that any water quality-based
effluent limits in the permit are derived
from and comply with the applicable
State or Tribal water quality
requirements. A permit that does not
include a defensible mixing zone
analysis might not fully protect
downstream designated uses. A
common example is where a discharge
mixes slowly (i.e., incomplete mixing is
occurring), but the permit limit is based
on an assumption that the entire design
flow of the stream rapidly and
completely dilutes the effluent. When
this does not occur and not all of the
dilution water mixes rapidly with the
effluent discharge, the result may be a
lengthy downstream plume (i.e.,
mixture of effluent and surface water)
with water quality characteristics that
exceed applicable chemical-specific or
toxicity criteria, are potentially lethal to
aquatic life, and may impair the
designated use. Such plumes are of
concern because:
(1) Chemical-specific criteria, ambient
toxicity criteria or other narrative
criteria may not be achieved in the
extended plume;
(2) Effluent plumes can extend far
downstream, causing impact beyond the
limited area of a mixing zone and
resulting in use impairment;
(3) There may be intakes for public
drinking water systems located
downstream, but within reach of an
extended plume;
(4) Effluent plumes may be located
along the shore in shallow waters that
are critical nursery areas for sensitive
species and which constitute important
or critical habitat, particularly in large,
channelized rivers;
(5) Aquatic life might be attracted to
the plume because of its temperature
differential or other characteristics;
(6) Threatened or endangered species
may reside within or near the plume
area, and
(7) Additional dischargers may be
located downstream and the cumulative
effects of all discharges may not be
adequately considered, particularly
regarding unintended overlapping
plumes.
EPA believes the rate of ambient
mixing and the complete versus
incomplete mix decision is a critical but
frequently overlooked component of
water quality-based permitting.
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Although a mixing zone analyses
requires site-specific information and
additional resources, EPA believes that
the approach currently followed by
some States and Tribes might be too
simplistic, might allow lethality within
areas of critical habitat or ecological
importance and may not fully protect
designated uses. EPA's current thinking
is that the regulation should be made
more explicit as to the circumstances
under which mixing zones must be
supported by site-specific data and
analysis. EPA is considering the need
for specific requirements within the
regulation governing the development
and content of mixing zone analysis
procedures as part of State and Tribal
implementation procedures.
6. Narrative Criteria for Mixing Zones
Historically, States have relied on
narrative criteria as a means to provide
baseline protection for water quality, to
address toxicity from combinations of
pollutants or unknown pollutants
through whole effluent toxicity testing
and limits, and to control pollutants for
which there are no chemical-specific
criteria available. EPA has consistently
maintained that prevention of nuisance
conditions (e.g., materials that will
settle to form objectionable deposits,
floating debris, oil, scum, foam and
other matter, toxic conditions, etc.),
through the application of narrative
criteria, apply to all waters, at all times,
including mixing zones. Despite this
long-standing policy, EPA is unaware if,
in practice, States and Tribes have had
any difficulty ensuring the maintenance
of these narrative criteria within mixing
zones. EPA is interested in comment
which might identify any instances
where the application of narrative
criteria has created difficulties for States
and Tribes implementing these
provisions in mixing zones.
In addition, EPA has traditionally
interpreted these narrative "free froms"
as including a prohibition against
lethality in all waters, including within
mixing zones. However, lethality is a
non-conservative endpoint for
measuring toxicity. Section 101 (a) (3) of
the CWA establishes a goal of
prohibiting "the discharge of toxic
pollutants in toxic amounts" which
could be interpreted as applying to
chronic as well as acute toxicity. EPA
guidance on appropriate water quality
within mixing zones also recommends
that "the total time-toxicity exposure
history must not cause deleterious
effects in exposed populations of
important species, including post-
exposure effects" (EPA, 1973). EPA is
considering how such an interpretation
(i.e., applying chronic toxicity
endpoints to water quality within a
mixing zone) could be implemented in
the context of the application of
narrative criteria within a mixing zone.
Guidance developed by EPA in 1985
(TSD) established a rationale for
allowing zones-of-initial-dilution (ZIDs)
or acute mixing zones. That guidance
limited the use of ZIDs to extremely
small areas of the receiving water under
limited conditions and to discharges
using rapid diffusers which produce
effluent discharge velocities exceeding
10 feet per second. That guidance was
premised on the rationale that
organisms would be physically
precluded from maintaining a position
within the ZID, thus preventing lethal
exposures. Benthic and sessile
organisms were also protected where
ZID placement was controlled and
directed away from such critical areas
(e.g., near shore, shallows, etc.). In
addition, EPA reasoned, high rate
diffusers achieve compliance with both
acute and chronic criteria within a
smaller area, utilizing less receiving
water volume for dilution than other
discharge designs. Consequently, high
rate diffusers are believed to provide
greater protection of water quality by
their rapid dispersion of effluent within
a smaller volume of surface water.
Where acute criteria are not applied at
the end-of-pipe, current EPA guidance
provides for a number of alternative
means of protecting against lethality in
a mixing zone, even in situations that do
not rely on high rate diffusers.
Alternatives to requiring compliance
with acute criteria at the end-of-pipe or
employing a high-rate diffuser to ensure
compliance "within a very short
distance from the outfall" require a
significant amount of site-specific data.
Such site-specific data could be
requested of NPDES permit applicants.
It is EPA's experience that the collection
of this kind of data does not occur on
a routine basis. EPA is interested in
public comment on the relationship
between ZIDs or acute mixing zones and
narrative criteria prohibitions against
lethality and States' and Tribes'
experiences with the application of
acute mixing zones under varying site-
specific and discharge-specific
conditions. EPA is also interested in
comments on whether the water quality
benefits of using high rate diffusers
justify potentially detrimental effects on
stream bed or shore line habitat.
7. Mixing Zones for Bioaccumulative
Pollutants
States and Tribes should exercise
caution when evaluating whether a
mixing zone is appropriate in cases
where bioaccumulative pollutants are
present. The impacts of bioaccumulative
compounds may extend beyond the
boundaries of a given mixing zone with
resulting impairment of a water body's
designated uses, particularly where
stationary species (e.g. shellfish) are
present, where uncertainties exist
regarding the assimilative capacity of a
water body or where bioaccumulation in
the food chain is known to be a
problem. Sediment contamination has
also become a major concern in both
flowing and non-flowing water bodies.
Concerns about sediment contamination
require additional attention since
typical mixing zone evaluations focus
only on water column toxicity. The
effects of persistent and
bioaccumulative pollutants may not be
detected for some distance from the
point of discharge, well outside the
mixing zone, or possibly not in the
water column at all. Some members of
the public have expressed concern
regarding the use of mixing zones in
situations where bioaccumulative
pollutants are present in a discharge and
have urged EPA to develop specific
regulatory requirements prohibiting the
use of mixing zones where these
pollutants are present.
Mixing zone policies are developed to
address complete and incomplete
mixing conditions associated with point
source discharges. These policies
identify whether mixing zones are
allowed and define how a State or Tribe
will limit the amount of surface water
allocated to mixing under a variety of
circumstances. These circumstances
include considerations specific to the
effluent and pollutants discharged (e.g.,
toxicity, solubility) and to the water
body receiving the waste (e.g., shallow,
flowing or non-flowing, high flow or
low flow, critical habitat). The potential
for bioaccumulation problems can
depend on a number of site-specific
factors and the use of mixing zones for
bioaccumulative pollutants may be best
dealt with on a site- or basin-specific
basis. EPA's mixing zone guidance
emphasizes that the determination by a
State or Tribe that a mixing zone is
appropriate must be preceded by a
separate determination that there is
available assimilative capacity in the
receiving water. Localized water quality
concerns are to be balanced with the
larger scale issue of overall pollutant
loading to the entire water body or
segment. Perhaps concerns about the
fate and transport of bioaccumulative
pollutants are more effectively
addressed under total maximum daily
load (TMDL) development and
determinations of assimilative capacity
which incorporate information on water
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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, 115F.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
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any stream-specific or pollutant-specific
considerations. Stream design flows, if
they are used, must correspond to the
duration and frequency components of
the ambient water quality criteria
contained in the State or Tribal water
quality standards. Currently, States and
Tribes must justify the scientific validity
of their stream design flow policies
where they differ from EPA's
recommendations. States and Tribes
may also establish specific guidelines
for restricting dilution allowances in
individual cases (e.g., States and Tribes
may adopt special restrictions on
dilution allowances for human health
criteria where a discharge is within 2
miles of a drinking water intake).
EPA's Great Lakes Guidance and its
Technical Support Document for Water
Quality-Based Toxics Control identify
acute and chronic stream design flows
to be utilized in drafting permit limits.
The Guidance establishes a 7Q10 or 4-
day, 3-year biologically-based stream
design flow for implementation of the
aquatic life criterion continuous
concentration (chronic criteria); a 1Q10
for the implementation of the aquatic
life criterion maximum concentration
(acute criteria); harmonic mean flow for
implementation of human health
criteria; and a 90Q10 for the
implementation of wildlife criteria.
In cases where complete and rapid
mixing of effluent with receiving water
does not occur, site-specific mixing
determinations must be made. Although
the selection of fractions of stream
design flows for the assignment of
available dilution for point source
discharges does affect the size of the
regulatory mixing zone, such default
assignments are not hydrologically
linked to the actual behavior of the
effluent plume in the receiving water,
may not protect swimming and drifting
organisms or sessile or benthic
organisms and are not equivalent to a
mixing analysis. There may be other
instances where the reliance on a fixed
percentage of flow or cross-sectional
area of the receiving stream in lieu of an
actual mixing analysis may not reflect
the mixing behavior of an effluent. In
some high dilution situations, there may
be more rapid dilution occurring than is
assumed in dilution calculations.
If complete and instantaneous mixing
actually occurs, using less than 100% of
the design flow can be a means of
accounting for situations where the
actual assimilative capacity of the water
body is unknown. States and Tribes
typically determine water body
assimilative capacity based on ambient
background concentration of a
pollutant, when data on such
concentrations is available. The
assimilative capacity is the difference
between the background level of a
pollutant and the highest level that
would comply with the water quality
criterion. Where information on all
sources of a given contaminant to a
specific water body is incomplete, or
where the State or Tribe wishes to
reserve assimilative capacity for the
future, States and Tribes should allocate
less than 100% of the assimilative
capacity of that water body at design
flow by utilizing less than 100% of the
design flow for dilution. EPA is
interested in comment addressing the
use of these stream design flows or
fractions of stream design flows in
setting mixing zones and in reserving
assimilative capacity in a water body.
The Great Lakes Guidance allows
States and Tribes to use default
assumptions for available dilution in the
absence of site-specific mixing data. The
default dilution assumption for open
waters (e.g., lakes) provides for ten-to-
one dilution. The Guidance also allows
for a demonstration to determine actual
mixing zone water quality, size,
placement and behavior. Under the
Guidance, for open waters, in no case
can mixing zone size exceed that area in
which discharge-induced mixing
occurs. As a default, the Guidance
restricts the mixing zone for protection
of aquatic life from acute effects (i.e., the
dilution allowed in calculating limits
based on an acute aquatic life criterion
or CMC) to 2 parts receiving water to 1
part effluent, at water body design flow
or volume.
As a default for implementing criteria
for the protection of aquatic life from
chronic effects (CCC) in flowing waters
(e.g., rivers and streams), the Great
Lakes Guidance allows States and
Tribes to use up to 25% of the design
flow for dilution. If a site-specific
mixing analysis is performed, a larger
mixing zone may be established. Mixing
zones for acute aquatic life criteria in
flowing waters are limited to the final
acute value or FAV (2x the acute
criterion) just as in open waters. EPA is
interested in comment on whether this
FAV default "cap" approach is
appropriate for waters outside the Great
Lakes Basin.
As stated above, the Great Lakes
Guidance allows increases above the
default mixing zone allowances when
site-specific mixing zone analyses are
conducted. These demonstrations
compile data on the mixing behavior of
the effluent at a particular site (e.g., the
size, shape and location of the mixing
zone). The Guidance also required that
mixing zones maintain existing and
designated uses and comply with
narrative water quality criteria (e.g.,
"free froms").
The Great Lakes Guidance also
specifies that mixing zones may not
jeopardize the existence of threatened or
endangered species or their critical
habitat.
EPA advocates the watershed
approach to water quality protection.
For the water quality standards
program, the emphasis has been toward
refinement of designated uses and
incorporation of new and emerging
sophisticated and integrated analytical
tools as a means to better characterize
the ecological condition of water
resources and more effectively protect
designated uses (see section I (A)
"General Purpose and Vision" of this
document). The development and
implementation of mixing zone policies
by States and Tribes constitutes risk
management at the sub-watershed level.
EPA has consistently emphasized the
need to ensure that State and Tribal
mixing zone provisions protect the
designated uses of receiving waters.
Site-specific data collected through a
mixing zone analysis will ensure that
designated uses will be protected the
loss of ecological integrity from the
discharge of effluents will be prevented.
An emphasis on the protection of
designated uses and maintenance of
ecological integrity is essential to the
watershed approach. The watershed
approach requires increased site-
specific information on local aquatic
systems and an assessment of the
impact of all discharges to local
ecosystems. The watershed approach
also depends upon the meaningful
involvement of local communities in
risk management decision-making.
Explicit, clear implementation policies
provide the public with the information
necessary to understand decisions being
made by regulators and the impact of
those decisions on local resources.
Request for Comments on Mixing Zone
Policies and Implementation Procedures
EPA requests comment on the
following questions:
1. Should the regulation be changed
to expressly require States and Tribes to
include a statement in their water
quality standards indicating whether
mixing zones are allowed?
2. Should the regulation be changed
to expressly require States and Tribes to
specify procedures by which mixing
zone decisions for individual discharges
would be made?
3. Should the regulation be modified
to identify the minimum requirements
or elements for State and Tribal mixing
zone policies (including size, location,
and methodologies)?
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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 cost-
effective. Each of these three assessment
approaches relies on different kinds of
water quality data, measures different
endpoints and, in practice, will be
interpreted in the context of
implementing a water quality
management program that includes
assessment and pollution control. EPA's
policy on independent application is
based on the premise that any valid,
representative data indicating an actual
or projected water quality impairment
must not be ignored when determining
the appropriate action to be taken.
Independent application recognizes the
strengths and limitations of all three
assessment approaches.
The next three sections briefly
describe three assessment approaches
(biological, toxicological and chemical)
one could likely be evaluating when
using independent application. Those
three sections are then followed by two
parallel discussions on different uses of
water quality data. One use relates to
the NPDES permits program to
determine whether a permit must
contain water quality-based chemical or
toxicity limits, and what those numeric
limits should be. The other relates to the
use of such data to evaluate the quality,
or condition, of waters under the CWA
section 305(b) and 303(d) programs. At
the core of both of these contexts is the
question "are the present applicable
water quality criteria complete and
appropriate for the water body, and how
are we to measure attainment of the
present or future criteria that apply to
any water body in question?" Thus, in
its most basic sense, independent
application remains a water quality
standards question. Any changes to or
clarifications of the policy on
independent application must therefore
be considered first under the rubric of
water quality standards and then in the
separate contexts of permitting and
water quality evaluation which are
based on water quality standards.
States and Tribes routinely determine
whether water bodies are attaining their
designated uses and whether existing
pollution controls adequately protect
those uses. Some States and Tribes have
recommended to EPA that it modify the
independent application policy.
Currently, EPA's policy of independent
application is the same for both NPDES
permitting and water quality assessment
programs. However, EPA recognizes that
each of the programs has somewhat
different data needs and attributes.
Therefore, today's notice separates the
two distinct uses of independent
application to better focus the
discussion.
a. Biological Assessments. Biological
assessments are based on quantifying
differences between expected biological
community attributes such as structure,
function and condition (known as a
reference condition) and the biological
community attributes found at a specific
site being evaluated. The extent to
which the community at the site
deviates from the reference conditions is
indicative of the degree of impairment
at the specific site. The strength of
biological assessments is their ability to
provide a direct measure of the health
of aquatic ecosystems. Biological
assessments are also able to detect non-
chemical impacts (e.g., habitat loss,
sedimentation, temperature effects) in
addition to chemical toxicity problems.
States and Tribes that use biological
assessments, use them primarily to
evaluate the ecological condition of
water bodies and to determine whether
a water body is healthy, threatened, or
impaired (i.e., aquatic life use
attainment decisions). In some
instances, States and Tribes have used
biological assessments to establish
monitoring requirements in an NPDES
permit, but generally, most use
bioassessments to make non-regulatory,
general, water resource management
decisions. Data from a biological
assessment can be compared to a
gradient that shows the reference
(expected) conditions without
impairment on one end and the worst
situation on the other. States and Tribes
generally use the results to determine
whether additional measures are needed
to protect the water segment, or
determine how close to attainment an
impaired system is. Biological
assessments can also play a role in
linking impairment to causative agents.
This link is often not definitive, but can
be very useful in helping to identify the
causes and sources of many
impairments. Some States and Tribes
have used indicator species or groups to
distinguish effects of toxicity from
effects of organic enrichment. For
example, one State documented that a
midgefly larvae is found to be
predominant in areas contaminated by
electroplating or metal wastes. Although
biological assessments cannot be used to
predict conditions in a mathematical
modeling sense, over time they can be
used to indicate the direction of change,
and the degree of that change, in the
condition at a particular site. This
information, where it is based on
enough data using relatively sensitive
appropriate metrics, can be very
valuable in deciding whether the
current condition is likely to be
maintained under similar conditions in
the future, or whether there are early
warning signs of biological impacts
giving reason to believe that additional
regulatory actions may be needed to
prevent water quality standards
impairment. Regulatory actions that are
a response to measured change in
biological condition will tend to be
restorative more than preventative (i.e.,
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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 chemical-
specific assessment can be preventative
as well as restorative.
Basing regulatory and management
decisions on chemical assessment of
water quality is an important and
proven aspect of water quality
assessment and protection. However, as
an indirect measure of aquatic health,
one of the principal limitations to
chemical assessments is dependence
upon chemical-specific benchmarks
(such as chemical water quality criteria)
for determining whether water quality is
suitable or unsuitable for attaining and
maintaining aquatic life uses. As noted
elsewhere in this notice, stressors other
than specific chemicals in a water body
are often a significant or even
predominant cause of nonattainment of
aquatic life uses. EPA's current thinking
is that complete reliance on chemical-
specific assessments of water quality is
too narrow of a focus and fails to
provide information on other important
ecosystem stressors. In addition, as
noted elsewhere in this notice, there are
currently water quality criteria for the
protection of aquatic life for 31
chemicals. There are tens of thousands
of chemicals discharged into surface
waters. (Note, however, that the
chemicals for which there are criteria
tend to be the most frequently
discharged). Thus there is the added
problem of too few criteria and too
many chemicals, making it
inappropriate to rely exclusively on the
chemical-specific approach. Another
substantial limitation of chemical-
specific benchmarks is that for a given
site, the benchmarks that are used, may
not be the best that are available to
reflect the level of protection applicable
at the site. For example, site-specific
aquatic life criteria are generally
different (higher or lower) than the
national recommendations for the same
chemical. And yet absent site-specific
criteria, the national recommendations
are often used.
2. Independent Application and Water
Quality Assessments
a. Independent Application. States
and Tribes often collect or have access
to monitoring data that measure the
concentration of specific chemicals in
an effluent or water body, the level of
toxicity present in ambient water or
discharges to a water body and/or the
biological community composition
within a water body. These data are
then interpreted by comparing them to
reference conditions or criteria to
determine whether or not aquatic life
uses are attained. EPA's 1991 policy on
independent application was explicit
about the use of independent
application in water quality programs:
"This policy, therefore, states that
appropriate action should be taken
when any one of the three types of
assessment determines that the standard
is not attained. States and Tribes are
encouraged to implement and integrate
all three approaches into their water
quality programs and apply them in
combination or independently as site-
specific conditions and assessment
objectives dictate." In implementing
this policy, EPA recommends that data
from the three assessment approaches
be applied independently in water
quality programs since each method
provides unique and distinct
information on the characteristics of the
water body. In other words, EPA
recommends that differences in
assessment results be resolved in one of
two ways: either presume an adverse
impact when any one source of data
indicates an adverse impact, or
reevaluate the complete data set and
modify the applicable criteria to account
for the new site-specific information.
Given EPA's mission to protect the
environment and absent definitive data
to demonstrate that an assessment is in
error or otherwise biased, EPA presumes
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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)(l)(A), 40 CFR 130.7(b)(l). When
identifying waters pursuant to 303(d),
the methods used to determine non-
attainment of standards for water
quality reporting under 305(b) should
also be used. However, water bodies are
eliminated from 303(d) list
consideration if technology-based
controls or other required Federal, State,
Tribal or local requirements will result
in the attainment of applicable water
quality standards. TMDLS developed to
secure restoration of designated uses are
largely dependent upon chemical
criteria and assessment to define
acceptable pollutant loadings.
The question arises as to whether
States and Tribes have the flexibility to
exclude a water body from 305(b)
reports and 303(d), i.e., conclude that
the designated use was protected, even
in the face of data indicating one or
more excursions of the applicable
chemical-specific water quality criteria.
EPA would like to consider possible
mechanisms under the existing CWA
and the legal theories supporting them
to address these questions.
As with determining the need for
regulatory controls (permit limits),
similar data evaluation issues face
States, Tribes and EPA in performing
water body assessments for purposes of
sections 303(d) and 305(b) of the CWA.
With respect to such assessments, EPA's
goals for States and Tribes are twofold:
(1) to encourage the use of chemical,
toxicological, physical and biological
data in making water body assessments;
and, (2) to ensure that the data are
interpreted and reported in a consistent
and scientifically defensible manner so
that documents such as the 305(b)
report to Congress provide valid and
useful information on the status of the
Nation's waters as a whole, irrespective
of State or Tribal boundaries.
EPA recognizes that there may be
instances where these goals appear to be
in conflict. It is possible that as States
and Tribes implement biological
assessment programs, they may identify
new areas of impact that were
previously undetected using other
assessment techniques and that this may
lead to a reluctance on the part of States
and Tribes to develop the expertise
necessary to conduct biological
assessments. Although this tendency is
contrary to the goals and objectives of
the CWA, the fact is that addressing new
and previously unaddressed threats to
surface water quality places additional
strain on already limited State and
Tribal resources. Some also feel that
adherence to a strict independent
application policy for assessment
purposes discourages the use of more
data than minimally needed to make an
aquatic life use assessment. In most
cases, the minimal amount of data
would be a chemical grab sample for a
few water quality characteristics such as
temperature, pH, BOD, or dissolved
oxygen. Collecting minimal data for
assessment reporting is much easier and
less resource intensive for States and
Tribes that are required to increase their
reporting coverage, and these States and
Tribes would not have to deal with
differing interpretation of assessment
results.
However, EPA believes that
placement of waters on section 303(d)
and section 305(b) lists should be based
on broad thorough assessment data, not
on limited and narrow data. The former
will help ensure that targeted water
quality controls and management
actions are appropriate and will result
in water quality standards attainment;
the latter can result in significant
outlays of State and Tribal resources
targeted on waters where water quality
problems are not well understood. EPA
is considering how best to obtain
accurate, high-quality assessment data
and how to reconcile differences
between assessments conducted using
different techniques in a manner that
fosters consistency and remains
scientifically defensible.
b. Alternatives to Independent
Application.
There is considerable sentiment
among various stakeholder groups that
there is a need to better incorporate
more comprehensive data, particularly
biological data, into the water quality
assessment framework described above
and that doing so will facilitate
collection and use of more integrated
and insightful water quality data. EPA
shares this view. Some have used the
term "weight-of-evidence" to describe
an alternative to the present EPA policy
of independent application that could
facilitate integration of chemical,
physical, toxicological and biological
data into the assessment program.
However, EPA recognizes that
individuals' views about the meaning of
the term "weight of evidence" vary
considerably and this variation should
be addressed. The term "weight-of-
evidence" has been interpreted by some
to mean that one approach to
assessment, e.g., biological, could
routinely be used to override
conclusions drawn using another
assessment technique, e.g., chemical.
EPA believes that approach is
hierarchical, not a weight-of-evidence
approach. EPA's position is that each
approach, chemical, toxicological,
physical and biological has inherent
strengths and limitations and that all
valid water quality assessment data
generated under any of these
approaches should be used in assessing
the health of aquatic ecosystems, in
ways that adequately take into account
the strengths and limitations of each
approach.
EPA's current thinking is that as
forms of water quality assessment data
have become broader (chemical,
physical, biological and toxicological),
and as the amount of such data
increases, the water quality standards
and assessment programs need to
facilitate continued collection and use
of such data, and that doing so will lead
to more thorough water quality
assessments, more insightful water
quality criteria, and better descriptions
of aquatic life designated uses. EPA
would not support an approach that
could lead to collecting fewer and
narrower water quality data by States,
Tribes and dischargers. On the contrary,
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EPA's current thinking is that to employ
a weight-of-evidence approach, a State
or Tribe (or EPA) would need to have
a comprehensive set of water quality
data to evaluate the chemical, physical,
toxicological and biological conditions
in a water and to conduct ecological
impact assessment to determine the
precise causes of impacts (chemical,
physical, biological, and toxicological)
and how best to address them. EPA's
current thinking is that the most
appropriate context for using a weight-
of-evidence approach would be in
establishing criteria. In addition, as
discussed below, EPA is interested in
evaluating the use of a weight-of-
evidence approach for assessment and
reporting under section 305 (b) of the
CWA. However, once the criteria are
established for a water body, the
assessment for purposes of listing under
section 303(d) of the CWA and
permitting under NPDES, must be based
on all applicable water quality criteria.
EPA's 305(b) reporting guidelines
interpret the independent application
policy to apply to aquatic life use
assessments for State 305(b) reports, not
just to permitting for protecting waters
due to reasonable potential to violate
water quality standards. This policy
helps protect against dismissing
valuable information when evaluating
aquatic life use attainment, particularly
in detecting impairment. This approach
is most protective when there is limited
data available and when there is no
documentation on the rigor of the
assessment. EPA is concerned that lack
of information can provide false
confidence about the health of the
nation's water bodies. However, EPA is
now developing a comprehensive
approach for conducting aquatic life use
assessments which integrates chemical,
toxicological, physical and biological
data, and includes consideration of the
strengths and limitations of the
assessment methods and the data. This
shift toward more integrated
assessments is reflected in EPA's most
recent guidance to the States and Tribes
on conducting 305(b) assessments,
particularly in determining
nonattainment (EPA's Guidelines for
Preparation of the 1996 State Water
Quality Assessments (305(b)) reports,
EPA 841 B-95-001) and is the primary
focus of the Office of Water's Criteria
and Standards program Plan. The 1996
305(b) guidelines are consistent with the
Policy on Independent Application
while incorporating a weight-of-
evidence approach in determining the
degree of impairment (partial or
nonsupport). The 1996 guidelines do
not allow for a finding of full support,
or attainment, of aquatic life use when
there are differences in assessment
results. Under certain circumstances,
however, the guidelines allow for the
possibility of a finding of partial
support, even where results of different
assessments are not fully consistent.
Generally, in assessing severity of
impairment, assessments based on data
with high levels of information, or rigor,
should be weighted more heavily than
those based on data with low levels of
information, and, rigorous biological
data should be weighted more heavily
than other data types. EPA recommends
that the results of biological
assessments, especially those with high
levels of information, be the basis for
the overall aquatic life use support
(ALUS) determination if the data
indicate impairment. This is because
rigorous biological data provide a direct
measure of the status of the aquatic
biota and detect the cumulative impact
of multiple stressors on the aquatic
community, including new or
previously undetected stressors.
Determining the level of information
or rigor for each assessment is a critical
component of the 305 (b) guidelines on
making an ALUS determination. The
levels of information allow
characterization of the quality and the
temporal and spatial coverage of the
data States and Tribes utilize to conduct
their use assessments. Levels of
information are identified for
assessments based on biological,
physical, chemical and toxicological
data. For example, measures of the
condition of the aquatic community
using indices incorporating multiple
assemblages of aquatic organisms based
on a regional reference approach would
rate higher than a measure of a single
organism or single metric or annual
fixed station monitoring for chemical
contaminants. Likewise, three years of
bi-monthly fixed station monitoring for
chemical contaminants would rate
higher than annual fixed station
monitoring for the same chemicals or a
biological measure of a single organism
or metric. Understanding the breadth
and robustness of the assessment
methods used in evaluating whether a
water body is attaining its designated
aquatic life use is important information
for EPA, the States, and the public.
In the future, EPA will be evaluating
possible scenarios where a finding of
full support could be justified despite
differences in assessment results. For
example, a finding of full support based
on rigorous biological data may be
justified despite differences with
chemical specific assessment results
depending on the magnitude and
frequency of the chemical exceedances
and the applicability of the chemical
benchmark to the site. It will be
important for EPA to carefully evaluate
such potential scenarios and to define
the adequate data requirements and
level of rigor necessary to support a
determination of full support despite
differences in assessment results.
Equally important, EPA will need to
carefully consider the ramifications of
such determinations on other parts of its
water program.
Another permutation of the weight-of-
evidence approach to aquatic life use
assessment is to establish a hierarchy in
which the results of one method could
always override the other methods
should there be difference in assessment
results. Most frequently, it has been
argued that biological assessments could
always override chemical assessments
in determining whether the designated
aquatic life uses are being attained.
Some prefer this approach because a
rigorous biological assessment provides
a direct measure of existing ecosystem
health and have expressed concern that
the policy of independent application
oversimplifies the relationship among
different data sets used to assess current
water quality conditions. Proponents of
this approach contend that biological
assessment is an integrated assessment
that incorporates the information that
would be provided through either
chemical or toxicological assessments
into a single, comprehensive measure of
aquatic ecosystem health. Some
advocate the acceptance of rigorous
biological data as the ultimate arbiter of
aquatic life use attainment. They also
suggest that, at least with respect to
current aquatic life condition
assessments, chemical, toxicological,
and biological assessments are not
independent; each measures the same
assessment endpoint, but from different
stressors. These proponents say that
biological assessment is the only
assessment approach available to
integrate and reflect current effects from
chemical, toxicological, physical, and
nonpoint source stressors. Because of
this they suggest that rigorous data
based on biological assessments and
criteria should automatically supersede
data from other sources when
determining aquatic life use attainment.
Some contend that if biological data
demonstrate that biological criteria are
attained, then the water body is
attaining its designated use, even if
other monitoring data such as
toxicological or chemical data
demonstrate an excursion, or potential
for an excursion, above a water quality
criterion.
Some also contend that rigorous
biological assessments should be used
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36799
to supersede assessments based on
predicted impacts such as water quality
modeling and wasteload allocations in
decision making for aquatic life use
assessments. One concern with this
perspective is that non-rigorous
biological assessments could be used in
such situations, though EPA has 305(b)
reporting guidance which suggest
minimum quality of biological
assessments that could also be used for
these situations. In this guidance, EPA
recommends using more than one
assemblage (fish and/or macro
invertebrates/and or algae), several
index values or metrics (multiple
metrics), an index period for sampling,
and ecoregional or other biogeographic
regional calibration.
EPA agrees that rigorous biological
assessment based on adequate site-
specific data is a direct assessment of
aquatic ecosystem health, unlike
chemical and toxicity assessments.
However, biological assessments are less
well suited for use in preventing water
quality impacts and will only reflect
impacts once they have occurred.
Though this may be less of a concern in
waters with a relatively constant level of
discharge where there has been ongoing
biological assessment. A second
objective of water quality assessment
under the CWA, beyond assessing when
the aquatic life use is impaired, is
assessing when stressors, if left
unchecked, will cause impairment. As
discussed above, the chemical-specific
approach is especially strong for use in
identifying and predicting impacts
before they happen.
EPA is concerned that the use of a
hierarchical approach may ignore or
undermine valuable information,
whether that information is biological,
physical, chemical, or toxicological, and
not trigger the appropriate action to
address the inconsistency (e.g.,
evaluation of existing criteria and
development of site-specific criteria).
Therefore, EPA does not support such
an approach. EPA has a number of
concerns with any approach wherein
data from certain assessment techniques
may be automatically superseded by
those from others. A primary concern is
the failure of such a system to make use
of all valuable information. In all cases,
criteria, whether chemical-specific,
toxicological, physical or biological, are
derived with the intent of identifying a
threshold beyond which unacceptable
impacts to aquatic ecosystems are
expected to occur. In most cases, it is
expected that when different assessment
techniques (i.e., chemical and
biological) are used for determining
attainment of aquatic life uses, the
techniques will yield similar results if
all are done rigorously. In addition, it is
expected to be rare for chemical
assessments to indicate nonattainment
where biological assessment indicate
attainment; analyses conducted by the
State of Ohio confirm this. (See Yoder,
C., "Answering Some Concerns about
Biological Criteria Based on Experiences
in Ohio."). However, it is also expected
that in certain cases, different
assessment techniques will result in
different determinations of aquatic life
use attainment due to the fact that each
technique evaluates aquatic life use
attainment differently, and some take
into account safety factors for ensuring
future attainment while others focus on
the current status of the condition.
When different assessment techniques
that are intended to measure similar
environmental endpoints and yield
comparable results fail to do so, it may
be an indication that assumptions
underlying the criteria are not valid for
a particular site, or that the data were
not rigorous.
While in some cases it may be
appropriate to weigh one set of data
more heavily than another in making a
use attainment determination, in others
it may be preferable to take advantage of
such circumstances as opportunities to
validate and cross-check criteria,
making adjustments as indicated by the
data. This could result, for example, in
an adjustment to a specific chemical
criterion in a particular water if rigorous
biological assessment indicated that
such an adjustment is appropriate. Such
information is also useful to EPA in
improving national criteria development
methodologies.
Lack of comparability in assessments
is also a concern for either a weight-of-
evidence or a hierarchical approach to
aquatic life use assessments. Therefore,
it is important that there be a common
understanding between States, Tribes
and EPA as to how conflicts in data
interpretation will be resolved in
evaluating and reporting water quality.
Developing comparable methods to
handle data conflicts will make
comparisons between States and Tribes
more useful, such as in 305(b) reports.
Without a consistent approach to
resolving data conflicts, assessments of
water quality data at the national level
becomes problematic. EPA's policy of
independent application is one way of
providing a consistent and defensible
framework for data evaluation in order
to minimize this problem.
Request for Comments on integration of
data in water quality assessments
EPA is interested in comment on how
chemical, physical, toxicological, and
biological assessments can be effectively
incorporated and implemented in State
and Tribal water quality standards
programs to achieve the goals of the
CWA.
EPA requests comments on the
following questions:
1. How can conflicting interpretations
of water quality assessment data be
reconciled in a scientifically defensible
manner? Should each kind of water
quality information stand alone as a
scientific measure of current water
quality conditions and ecosystem
health? Alternatively, are there
situations where one type of data should
be given more weight than another in
determining use attainment?
2. How should States and Tribes
evaluate water quality information
generated using chemical, toxicological,
physical, and biological methods when
determining use attainment status?
3. When interpretation of water
quality data indicate inconsistent
results, what factors (i.e., data richness),
if any, should EPA consider relevant to
determining "appropriate actions"?
4. Should EPA explicitly address in
the water quality standards regulation
the evaluation assessments using
chemical, toxicological, physical and
biological assessment methods?
5. Should an approach be instituted
where independent application may be
relaxed for water quality assessment
strategies and decisions when a State or
Tribe has established a comprehensive
monitoring and assessment program
including biological monitoring and
assessment? What guidelines should be
used to evaluate a State or Tribal
biological monitoring and assessment
program?
6. How should the policy of
independent application address the
distinction between situations where
adequate rigorous data are available for
each assessment technique and
situations where available data for one
or more of the assessment techniques
are limited in quantity or quality?
Specifically, should the policy be
modified to more explicitly encourage
or require, where feasible, additional
monitoring, particularly where limited
data are to be used as a basis for
regulatory action?
3. Independent Application and NPDES
Permitting
a. Independent Application. Clean
Water Act section 101 (a) states that
"[t]he objective of this Act is to restore
and maintain the chemical, physical,
and biological integrity of the Nation's
waters." In the context of implementing
water quality-based pollution controls
under the NPDES program, EPA has
maintained that independent
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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)(l)(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)(l)(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)(l)(iii)-(v) describe the
conditions under which water quality-
based effluent limits for specific
chemicals and for whole effluent
toxicity are required in NPDES permits.
While these regulations do not
specifically use the term "independent
application," the concept is expressly
laid out. These regulations require
chemical-specific limits when the
permitting authority determines there is
a reasonable potential for the discharge
to cause or contribute to the excursion
above the chemical-specific criterion.
Likewise, the regulations require limits
for whole effluent toxicity if the
permitting authority determines there is
a reasonable potential for the discharge
to cause or contribute to the excursion
above the numeric criterion for toxicity
or narrative criterion for water quality.
Except under limited circumstances
(where the State or Tribe lacks a
chemical-specific criterion for a
pollutant of concern), these regulations
do not allow a permitting authority to
forgo one type of limit, e.g. a chemical
limit, where another type of data, e.g.,
toxicity, indicate no toxicity. Instead,
the two types of data are required to be
considered independently.
The independent application policy
provides a consistent and coherent
protocol for resolving conflicts in
interpreting monitoring data when
determining "reasonable potential."
Where such conflicts exist and cannot
be reconciled, independent application
directs States and Tribes to presume
that the data that indicate a current or
potential impact are valid and to take
appropriate steps to prevent or
remediate the impact. The
reconciliation phase allows a State or
Tribe to gather additional or more
detailed data prior to taking regulatory
action. Data interpretation conflicts may
be best addressed by identifying the
cause of the conflict and recalibrating
the models and criteria to better reflect
the newly acquired site-specific
information. However, if the causes of
the data interpretation conflicts cannot
be resolved, under independent
application, the State or Tribe must take
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36801
action based on the data indicating
impairment or the reasonable potential
for impairment of the water body.
EPA believes this procedure for
addressing conflicting interpretations of
monitoring data is appropriate for a
number of reasons. First, as stated
earlier, each of the different assessment
techniques monitors aquatic ecosystem
health from a slightly different
perspective. Consequently, it is entirely
plausible that only one of the
assessment techniques would detect a
real or potential impact. Second,
assuming that the data generated by the
different techniques are of comparable
quality and relevance, an indication of
a water quality problem using any of the
techniques is sufficient reason to
implement controls. That being the case,
EPA believes the independent
application of water quality data in
determining when water quality-based
effluent limits are necessary for
individual dischargers is consistent
with the CWA.
Reconciliation of data interpretation
conflicts allows flexible evaluation of
data. Once a permit application is
received from a discharger, States and
Tribes frequently engage in discussions
with the discharger over the quality and
representativeness of the data. This
period of data review and evaluation is
also an ideal time for addressing any
data interpretation conflicts in order to
ensure that permitting decisions are
defensible and the permit limits that are
imposed are necessary to protect
designated uses. States and Tribes,
together with permittees, may obtain
additional data to verify earlier data or
conduct timely studies to support the
development of site-specific criteria.
Ultimately, these site-specific criteria
may serve as the basis for a permit limit,
or a decision that it is not necessary to
limit a pollutant in a particular
discharge. All of the actions above are
consistent with the independent
application policy and the CWA.
Critics of EPA's policy believe either
that data from certain types of water
quality assessments have inherently
greater value than data obtained by
other means or that, in a sense, data
quality and ecological significance
should be averaged, such that if data
obtained from two different assessment
methods agree and data from a third
disagree with the other two, the two
could "outweigh" the one. In either
case, all of the available data would be
considered together, under the
assumption that each assessment
technique measures a similar endpoint.
Under such an approach to data
evaluation, limits on effluent toxicity
would be appropriate and acceptable as
surrogates for chemical-specific limits.
Similarly, biological assessment data
that do not indicate unacceptable levels
of impact on the biological community
could serve as the basis for a decision
not to include either chemical-specific
or effluent toxicity limits designed to
support an aquatic life use in a facility's
discharge permit. Proponents of this
view argue that independent application
forces them to take inappropriate
regulatory actions when faced with
conflicting assessment data. EPA does
not agree in principle with this view.
b. Alternatives to Independent
Application. States, Tribes,
municipalities, and dischargers have
expressed concerns that the policy of
independent application results in more
protection than is necessary to attain
and maintain aquatic life designated
uses. Many express a preference for an
approach which invests data obtained
using certain assessment techniques
with greater credibility than those
obtained in other ways. Such an
approach, as discussed above, is
sometimes referred to as a weight-of-
evidence approach. Under such an
alternative approach, assuming a high
level of confidence in all the available
data, one form of data—usually it is
argued biological data— would be the
ultimate arbiter of whether water
quality-based effluent limits are needed
in a discharger's permit. To determine,
for example, whether a water quality-
based effluent limit is needed for a
particular chemical pollutant, the risk of
adverse impact on the aquatic
community would be determined based
on all of the available data relying more
heavily on high quality, thorough
biological data and on the judgment of
the individual conducting the
evaluation. Several States and members
of the regulated community have
advanced this approach as preferable to
EPA's independent application policy,
arguing that such flexibility to exercise
judgment is appropriate.
EPA's current thinking is that it
should not promote an alternative
approach to making "reasonable
potential" decisions that places greater
emphasis on biological data. Instead,
EPA's current thinking is that such an
evaluation of water quality and
ecosystem health to determine the
appropriate and applicable criteria
against which discharges will be
evaluated is most appropriately done
during the setting of the applicable
criteria for a water body. In that arena,
it may be feasible to use biological
assessment as a basis for determining
the appropriate criteria for a given water
body. However, once the criteria are set,
EPA believes that the current regulation
requires "reasonable potential"
evaluations against all the applicable
criteria, and that the policy of
independent application in this context
is appropriate.
If biological data indicate that
designated uses are being attained in
spite of projected or actual chemical-
specific criteria exceedances, then
additional site-specific analysis should
be done to ensure that controls are
developed that are necessary to
adequately protect the water body from
use impairment. Site-specific
approaches could include mixing zone
studies, more refined water quality
modeling to support wasteload
allocation, or the development of site-
specific criteria. In any case, chemical-
specific and toxicity criteria are proven
and necessary bases of water quality-
based effluent limits. In "reasonable
potential" analysis, chemical-specific
monitoring is usually focused on
pollutant concentrations in the effluent
and the projected ambient result of
those concentrations being discharged.
Thus, this type of analysis commonly
yields projected rather than measured
water quality impacts. Where biological
impact is not detected using biological
assessment methods, it is possible that
impairment that is projected and
plausible, may simply have not yet
occurred. However, where discharges to
a stream have been relatively constant
over time and there has been ongoing
biological assessment, this would be
less of a concern. EPA's view is that it
would be inappropriate to ignore
projected impairment simply because
the impairment has not yet been
observed in the environment.
An additional argument in favor of
retaining the independent application
policy for "reasonable potential"
determinations has to do with the
suitability of certain types of data and
the unsuitability of others for certain
applications within the water pollution
control program. For example,
biological data are not amenable in the
same way as chemical-specific data for
use in waste load allocations, load
allocations, total maximum daily load
calculations or antidegradation reviews.
An approach that would allow
biological data to negate a finding of
"reasonable potential" would suggest
possible site-specific inadequacies of
particular criteria without providing the
information needed to determine
definitively whether or not the criteria
are appropriate or what any alternative
criteria should be. As a consequence, a
void would be created in the
implementation of State or Tribal water
quality standards which would render
them unable to perform all of their
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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)(l)(C) and the implementing
regulations at 40 CFR 122.44(d). On
occasion, States, Tribes and dischargers
have asserted that biological and
toxicity data from specific waters
conflict with chemical data. EPA's
current thinking is that instances of
clear disagreement between biological
and toxicity data and chemical data are
infrequent. Based on this belief, EPA
would not support a radical shift away
from chemical criteria and limits or
toxicity criteria and limits. Those tools
are simply too important as proven tools
for assessing potential impacts to
surface waters and improving water
quality. EPA's current thinking also
suggests that it is important for there to
be flexibility to resolve instances of
disagreement between different forms of
data and that perhaps mechanisms for
such flexibility can be clarified or
improved. EPA's current thinking is that
through collection of broader and more
thorough water quality data, EPA, States
and Tribes will be able to develop more
complete profiles of water body
conditions and stressors and that
through such evaluation the "necessary
actions" (e.g., water quality-based
effluent limits for one or more
pollutants, listing of the water body as
not attaining its aquatic life designated
use, or best management practices to
address nonpoint sources of pollution)
to improve water quality in a given
water will become more obvious.
Disagreement between biological,
toxicity and chemical data for the same
water is cited by some States and
dischargers as a potential situation in
which independent application would
force unnecessary and burdensome
requirements on dischargers. Those
opposed to independent application of
criteria would like to see States and
Tribes given greater latitude to
determine when limits based on a given
criterion are necessary. They suggest
that this could be achieved if States and
Tribes were to include, in the chemical-
specific criteria or toxicity criteria
portions of their water quality
standards, statements explaining
circumstances under which the
otherwise applicable criteria would not
apply at a particular site or would have
to undergo some review and revision,
while assuring the designated use of the
water body would be maintained. Such
circumstances could include where the
form of the pollutant in the effluent or
receiving water is not the form
addressed by the chemical criterion in
the State or Tribe's standards; or, where
a substantial amount of biological and
or toxicity data indicate that (discharges
of the pollutant at levels that would
exceed the chemical criteria are not
causing the aquatic life use in a
particular water body or segment of the
water to be impaired. If these conditions
could be met, permitting authorities
would have the flexibility to determine
that a numeric water quality-based
effluent limit for the pollutant in
question is not required, or that an
alternate limit should apply. This type
of flexibility, to rely on biological
evaluations in the criteria setting phase,
where data are sufficient to support
such flexibility, could be a strong
incentive for States and Tribes to
develop stronger biological criteria and
assessment programs including
monitoring reference areas and
complete chemical and toxicity
monitoring programs, including site-
specific data on most sensitive species
to chemical (s) for which flexibility is
being sought. EPA approval of water
quality standards implementing such an
option requires acceptance of an
interpretation that sections 301 (b) (1) (C)
and 303(c)(2)(B) of the CWA allow
States and Tribes to identify, within
their water quality standards, conditions
or circumstances which would render
specific numeric criteria not applicable
to certain waters in specific instances,
or alternatively in need of refinement.
EPA has significant technical
questions about how such an option
could be implemented within the
context of a State's or Tribe's water
quality standards. EPA is especially
interested in detailed technical
comments describing how such an
option would be included in a State's or
Tribe's water quality standards, how
such an option would ensure protection
of designated uses in water bodies
where criteria are deemed not
applicable. In addition, EPA is soliciting
comment on specific procedures that
could be used by a State or Tribe to
arrive at a decision that a criterion is not
applicable at a specific site. In
particular, EPA is interested in technical
evaluations of what types of data would
be necessary to support such a decision,
the quantity and quality of the data and
how the data would be evaluated.
Finally, EPA seeks detailed technical
comments indicating how other
elements of the water quality standards
program would function in situations
where chemical or toxicological water
quality criteria were adjusted based on
biological assessments. For example, if
a State or Tribe were to employ the
option discussed above, it is not
apparent how critical water quality
program elements such as determining
the need for permit limits or whether or
not a new discharge could be allowed to
a stream segment could occur absent
chemical-specific or toxicity-based
criteria applicable to the water body. To
be workable, this option may need to be
paired with a scientifically defensible
mechanism for making decisions about
activities such as permit limits and load
increases. Since chemical criteria and
chemical-specific interpretations of
narrative criteria currently are the
principal benchmark used for these
functions, would pursuing the option
discussed above be workable, or would
it introduce a level of complexity into
State and Tribal water quality standards
that could result in slowed or
suspended water pollution control
programs, and expose aquatic
ecosystems to greater risk because of the
lack of an identified threshold of
impact?
EPA's current thinking is that
significant flexibility already exists
within the current regulatory framework
to account for available biological and
toxicity data. For example, numeric
criteria, once adopted, may be modified
to better reflect conditions at a specific
site. Bioassessment and toxicity data
can play a valuable role in identifying
sites where conditions differ sufficiently
from those assumed in the calculation of
the national or State or Tribe-wide
criteria to warrant site-specific
modification of the criteria.
Bioassessment and toxicity data can also
provide useful information in
identifying instances where a given
constituent in an effluent is
toxicologically distinct from a similar
substance for which a criterion is
available, indicating the need for a
separate criterion for the constituent in
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36803
question. Establishing site-specific
criteria would provide relief similar to
that contemplated in the option
proposed above.
Lastly, public participation is a basic
tenet of the water quality standards
development process. Public
participation is also sought in the
context of issuing NPDES permits.
During standards development, public
input is sought to assist the regulatory
agency in identifying the appropriate
water quality goals for the waters under
the jurisdiction of a State or Tribe.
During NPDES permit issuance, public
input is again sought to verify that the
permit proposed to be issued is
consistent with the water quality goals.
Some assert that these two public
participation steps seek input on
different questions and are not
interchangeable. Does the weight-of-
evidence option discussed above reduce
the opportunity for meaningful public
participation in the standards setting
process by making it more difficult for
the public to determine which water
quality criteria will apply to which
water bodies, and, as a result, what the
water quality goals for an individual
water body are? EPA is considering how
a weight-of-evidence approach might be
implemented in a manner that does not
restrict the opportunities for meaningful
public participation in the water quality
goal setting process.
Request for Comments on Independent
Application
EPA requests comment on the
following questions:
1. What is the rationale for modifying
the independent application policy as it
pertains to NPDES permitting? Under
what circumstances could it be
justified?
2. If there are circumstances where an
approach other than independent
application is acceptable, should any
one type of water quality data receive
greater weight and why?
3. How should States and Tribes
evaluate effluent data generated using
chemical, toxicity and biological
methods in determining reasonable
potential to cause or contribute to an
impairment?
4. Would checks or oversight
mechanisms be necessary to ensure that
where decisions about reasonable
potential are based on chemical, toxicity
and biological methods, such decisions
are made with integrity? For example,
EPA or public oversight?
5. Are there any cases which indicate
that either chemical-specific, whole
effluent toxicity or biological
approaches do not legitimately
represent some aspect of use
attainment?
6. Should EPA explicitly incorporate
into the water quality standards
regulation the independent application
policy?
7. Should independent application be
addressed the same or differently for
permitting than for assessment and use
attainment decisions under 305 (b)
reporting and 303(d) listing?
8. If EPA were to separate the use of
independent application in determining
the use attainment status of a water
body from the use of independent
application when determining
reasonable potential for an effluent,
what approach, independent
application, weight-of-evidence, or
hierarchical, should be used for use
attainment decisions? NPDES
permitting? What would the
implications be if the programs used
two different policies?
9. Would a policy allowing numeric
criteria to not apply to all waters where
supported by scientifically defensible
data be workable? Would it
unnecessarily complicate the regulatory
program, for example by delaying the
issuance of permits? Are existing
mechanisms of criteria setting and
permit issuance sufficiently flexible?
IV. Summary and Potential Program
and Regulation Changes
EPA believes that the water quality
standards program and decisions it
yields will continue to be the focus of
growing pressure and scrutiny as
solutions to remaining surface water
quality problems in this country are
found to be increasingly elusive,
difficult, and/or expensive. The task set
forth by the Clean Water Act is to
improve water quality even where it is
difficult to do so. To accomplish this
task, EPA envisions a national water
quality standards program in which: the
best possible information on whether
designated uses are being attained and
how to attain and maintain them is
available and used; water quality
criteria are selected from a wide-ranging
menu of scientifically sound criteria and
tailored to each watershed; and national
norms of consistency and flexibility in
State and Tribal water quality standards
are clear.
With this vision in mind, EPA,
through this ANPRM, begins a review of
the water quality standards regulation in
a public forum in an attempt to identify
possible amendments to the regulation
and new guidance or policy that may be
needed to address three distinct
objectives: (1) eliminate any barriers to,
and otherwise enhance State and Tribal
implementation of, watershed-based
water quality planning and
management; (2) facilitate use of new,
more integrated water quality
assessment and criteria science in water
quality standards programs, and; (3)
improve the regulation so that it can be
implemented more efficiently and
effectively (including cost-effectively).
The preceding pages of this ANPRM
outline current regulatory provisions,
accompanying guidance and policy, and
current practices in the core areas of the
water quality standards program. Each
section of the ANPRM identifies issues
that have been raised to EPA that come
out of the collective experiences of
States, Tribes, cities, industry and
environmental advocates, as well as
EPA's experience. The issue discussions
are followed by specific questions that
are intended to elicit focused comments.
It is important for commenters to focus
on these specific questions as a vehicle
for developing comments. It is equally
important for commenters to develop
ideas that address the three objectives
above in a more general sense and to
identify the five to seven highest
priority issues the commenter believes
EPA should address in a follow-on
regulatory proposal. EPA welcomes
ideas on how the water quality
standards regulation, policy and or
guidance can be revised to facilitate
water quality management on a
watershed basis. In requesting comment
on eliminating barriers to and
facilitating implementation of
watershed-based water quality planning
and management, EPA directs
commenters' attention primarily to the
sections on designated uses, criteria,
antidegradation, mixing zones and
independent application. In requesting
comment on how to facilitate use of
new, more integrated water quality
assessment and criteria science in water
quality standards, EPA directs
commenters' attention primarily to the
sections on biological criteria, and
independent application. In requesting
comment on how to improve the
efficiency and effectiveness (including
cost-effectiveness) of the water quality
standards program, all sections of the
ANPRM are relevant for review.
EPA seeks a water quality standards
program that protects the nation's
waters as envisioned in the CWA, that
establishes requirements that are
necessary to attain and maintain healthy
and sustainable ecosystems, and that is
flexible enough for States and Tribes to
protect water quality and at the same
time avoid costly requirements that
have little or no environmental benefit.
Below is a brief summary outline of
the potential changes to the water
quality standards program and
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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.
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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)ofl996
Under the RFA, (5 U.S.C. 601 etseq.),
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
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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,
Assis tan t Adminis tra tor for Wa ter.
[FR Doc. 98-17513 Filed 7-6-98; 8:45 am]
BILLING CODE 6560-50-P
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