EPA REGION VIII GUIDANCE:
ANTIDEGRADATION IMPLEMENTATION
a®.
Requirements, Options, and EPA
Recommendations Pertaining to State/
Tribal Antidegradation Programs
August 1993
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U.S. Environmental Protection Agency Region VIII
Water Management Division
999 18th Street Suite 500
Denver, Colorado 80202-2466
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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
REGION VIII
999 18th STREET - SUITE 500
DENVER, COLORADO 80202-2466
U S EPA Region 8 Library
8QC-L
999 18lh Si , Suito 500
Denver, CO 80202-2466
Dace: August 1, 1993
Subject: EPA Region VII Guidance on
Antidegradation Implementation
Dear Colleague:
I am pleased to enclose for your information and use a document titled EPA
Region VIII Guidance: Antidegradation Implementation. This guidance document is the
result of Regional staff efforts over the last year, as well as our collective experience in
working with state and federal antidegradation requirements over the last ten years. It
is my hope that this guidance will provide appropriate support to state and tribal
antidegradation programs within EPA Region VIII. Although all comments received on
previous drafts have been carefully considered in preparing this final version, issuance
of this guidance should not (and will not) end the dialogue between EPA, the states,
and tribes on antidegradation issues. Further discussion on specific topics will be
necessary as each of the states and Indian tribes in Region VIII progresses with its
respective antidegradation implementation efforts.
The enclosed guidance document has been developed to establish a clear
framework for consistency within EPA Region VIII on antidegradation issues. To
accomplish this purpose, the guidance identifies specific minimum expectations and
includes example, or "model," implementation approaches. However, the guidance
also allows states and tribes the flexibility to pursue innovative approaches and to focus
on particular problems. It is worth noting that the guidance emphasizes
implementation of pollution prevention measures and other reasonable alternatives to
allowing degradation as the focus of state/tribal antidegradation efforts to maintain the
quality of high quality waters.
To provide adequate continuing support to state/tribal antidegradation programs,
additional guidance will be forthcoming as the development of antidegradation
programs within Region VIII progresses. This additional guidance may take the form of
periodic revisions to this document, a compilation of "case studies" of general interest,
and/or EPA comment letters in support of state/tribal triennial reviews. As always, I
encourage you to notify us regarding your needs in this area.
Above all else, I hope the enclosed guidance will be useful to you in
implementing antidegradation requirements in EPA Region VIII.
Sincerely,
Max H. Dodson, Director
Water Management Division
Enclosure
Printed on Recycled Paper
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TABLE OF CONTENTS
EXECUTIVE SUMMARY ...... HI
CHAPTER 1: INTRODUCTION 1
What is antidegradation? 1
Why has EPA Region VIII developed antidegradation guidance? 2
What are the specific objectives of this guidance? 3
How is this guidance organized? 4
CHAPTER 2: THE MODEL ANTIDEGRADATION
PROCEDURE 5
Parti. Introduction 5
Part II. Definitions 6
Part III. The Antidegradation Review Process 7
Antidegradation Implementation Flow Chart 8
Part IV. Tier 3 Procedures 9
A. Waters Qualifying for ONRW Protection 9.
B. Direct Sources to ONRWs 10
C. Sources Upstream from ONRWs 10
D. Temporary and Limited Effects 11
Part V. Tier 2.5 Procedures 11
A. Waters Qualifying for OSRW Protection 11
B. Direct and Indirect Sources to OSRWs 12
C. Temporary and Limited Effects 13
Part VI. Tier 2 Procedures 14
A. Waters Qualifying for Tier 2 Protection 14
B. Significant Degradation 16
C. Evaluation of Alternatives to Lowering Water Quality ..19
D. Determination of Socio-Economic Importance 20
E. Ensure Full Protection of Existing Uses 23
F. Ensure Implementation of State-Required Point
and Nonpoint Sources 23
Part VII. Tier 1 Procedures 24
A. Waters Qualifying for Tier 1 Protection 24
B. Two Pan Requirement 24
C. Ensure Water Quality Sufficient to Protect
Existing Uses Fully 24
D. Ensure Full Protection of Existing Uses 26
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Part VIII.Documentation, Public Review, and Intergovernmental
Coordination 27
A. Documentation of Antidegradation Review Findings ...27
B. Public Review Procedures 27
C. Intergovernmental Coordination Procedures 28
Part IX. Questions and Answers 28
Antidegradation Review Worksheet.... 35
CHAPTER 3: PRIORITY ISSUES 41
What is Region VIII's bottom line7 41
What are the issues that must be addressed? 42
CHAPTER 4: DISCUSSION OF, AND RATIONALE FOR THE
MODEL IMPLEMENTATION PROCEDURE ..45
What are the principal features of the Region VIII model
implementation procedure? 45
What is EPA Region VIII's rationale on the major issues? 47
»¦ Activities Subject to Antidegradation Requirements 47
>¦ Antidegradation and TMDL Development 49
»¦ Proposed Activities Upstream of ONRW Segments 51
»¦ Antidegradation and Interstate Water Pollution 52
>• Defining Temporary and Limited Impacts to ONRWs .52
>• Tier 2.5 53
»• Identifying High Quality (Tier 2) Waters 54
> Significant Degradation 55
»¦ Cumulative Effects 56
»• Permitted Versus Existing Effluent Quality 56
»¦ Data Requirements 57
»¦ Determinations of Importance and Necessity 58
»¦ Identifying Existing Uses 1 59
»• Identifying Existing Uses 2 60
»¦ Impacts not addressed by the applicable water quality
criteria 61
APPENDICES 62
Appendix 1 - Background Information and References 62
Appendix 2 - State Approaches to Implementing Antidegradation ..65
Appendix 3 - EPA Region VIII Responses to Major Comments 78
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EXECUTIVE SUMMARY
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OVERVIEW
The purpose of this document is to provide assistance to the
states and Indian tribes located in EPA Region VIII with the develop-
ment of antidegradation policies and implementation procedures.
Such policies and procedures are required by the federal water quali-
ty standards regulation at 40 CFR 131.12. The document provides
and discusses a recommended or "model" procedure for implement-
ing antidegradation requirements, identifies the specific antidegrada-
tion issues that must be resolved by state and tribal antidegradation
procedures, provides background information relevant to federal
antidegradation requirements, and discusses how a number of key
antidegradation issues have already been addressed by the states.
PURPOSE OF ANTIDEGRADATION
The basic purpose of a state or tribal antidegradation program is
to promote the maintenance and protection of existing water quality.
Under this program, "waters of the United States" are typically pro-
vided antidegradation protection based on a system of three differ-
ent levels, or tiers. The level of protection that is provided to a spe-
cific segment depends upon a number of factors (e.g., in many states
a key determinant is whether the segment in question is attaining
"fishable/swimmabie" conditions). Antidegradation requirements are
typically triggered when an activity is proposed
that may have some effect on existing water qual-
ity.1 Such activities are reviewed to determine,
based on the level of antidegradation protection
afforded to the affected waterbody segment,
whether the proposed activity can be authorized.
Antidegradation review Findings must be docu-
mented and subjected to public review.
Antidegradation recognizes that existing water quality has inherent
value worthy of protection. Thus, unlike other aspects of water qual-
ity standards that are directed toward attainment of fully-protective
levels of water quality (as defined by the applicable criteria), the pur-
pose of antidegradation is to maintain and protect existing levels of
water quality.
1 A number of states limit application of antidegradation requirements to "reg-
ulated activities' (e.g., those requiring a permit or a water quality certification).
However, states and tribes have authority to define the scope of their anti-
degradation programs more broadly than this.
The basic purpose of an ant*-
degradation program is: to
maintain and protect exist*
vngwater quality*
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ANTlDEGRADATtON
STATE APPROACHES TO IMPLEMENTING
ANTIDEGRADATION
All nfty-seven states and territories subject to water quality
standards program requirements have established antidegradation
policies as part of their water quality standards. Many of these
antidegradation policies are identical to the federal policy con-
tained in the water quality standards regulation at 40 CFR 131.12.
The manner in which states and territories have implementated
these policies differs widely, presenting a broad spectrum of
approaches for addressing various issues. This variability has
resulted from a number of factors including, but not limited to, the
substantial level of state flexibility that is provided for by the feder-
al water quality standards regulation and EPA's implementing guid-
ance. Appendix 2 of this document contains a discussion of how
various state antidegradation implementation procedures address a
number of critical antidegradation issues.
FEDERAL ANTIDEGRADATION REQUIREMENTS
The federal requirements pertaining to antidegradation are
included in § 131.12 of the federal water quality standards regula-
tion. In essence, these requirements direct states to adopt antidegra-
dation policies and identify the procedures that will be followed in
implementing such policies. Certain minimum requirements exist
for both policies and implementation procedures. The regulation
requires implementation based on three levels, or tiers, of antidegra-
dation protection:
Tier 3: Maintain and protect high quality waters that constitute an
outstanding national resource, such as waters of national
and state parks and wildlife refuges and waters of excep-
tional recreational or ecological significance.
Tier 2: Maintain and protect existing water quality, where such
existing water quality exceeds levels necessary to support
propagation of fish, shellfish, wildlife, and recreation in and
on the water, unless the state finds that certain conditions
are satisfied. A key finding which must be made is that
allowing lower water quality is necessary because reason-
able non-degrading or less-degrading alternatives are not
available.
Tier 1: Maintain and protect existing in-stream water uses and the
level of water quality necessary to protect such existing
uses, whether or not such uses are included in the water
quality standards. This level of protection applies to all sur-
face waters.
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PRIORITY ISSUES
One of the primary purposes of this guidance document is to
provide clear direction to EPA Region VIII states and tribes on the
subject of antidegradation implementation. To this end. the guid-
ance identifies a set of "bottom line" issues that states and tribes will
need to address and clearly resolve within their antidegradation
implementation procedures to be assured of EPA approval.1 The
Region believes that identifying these bottom-line issues "up-front"
will assist states and tribes with developing complete and workable,
and hence approvable. antidegradation implementation procedures.
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REGIONAL RECOMMENDATIONS ON
ANTIDEGRADATION IMPLEMENTATION
This guidance document also includes specific recommended
approaches for addressing a number of antidegradation implementa-
tion issues. This is accomplished primarily by including a model
antidegradation implementation procedure in Chapter 2. The model
procedure is intended to provide an example of how state and tribal
antidegradation programs can address each of the Key issues. States
and tribes may develop their own version of the EPA Region VIII
model or a procedure entirely of their own design. A discussion of
the Region's rationale on many of the Key antidegradation issues is
provided in Chapter 4 of this guidance document. Among the more
significant features of the Region's recommended procedure include
the following:
>¦ Model (tier 3) procedures for protection of Outstanding National
Resource Waters (ONRWs) are recommended. New or expand-
ed direct sources of pollution to ONRW segments are prohibited
under the recommended approach. New or expanded
upstream sources are allowed provided that there will be no
change in ONRW water quality. The types of limited and tem-
porary impacts to ONRW segments that may be allowed are
defined. Model qualification criteria and procedures for desig-
nating ONRWs are also included.
>• A tier of antidegradation protection not currently required or
recognized under the federal water quality standards regulation
is recommended. A number of states have demonstrated the
utility of providing this extra level of protection (referred to as
tier 2.5). The recommended tier 2.5 procedures would provide
1 The Region notes that, on a number of these Key issues, there is a range of
approaches that would be deemed acceptable.
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¦/''T¦ A model (tier 1) procedure for identifying and protecting existing
uses1 is recommended. The model procedure presumes that
implementation of the water quality criteria established to pro-
tect designated uses will also result in protection of existing
uses. However, this presumption may be overcome based on
site-specific information that is available at the time of the
review or that becomes available as a result of public participa-
tion or intergovernmental coordination.
»¦ A number of questions and answers are included in the model
procedure to help explain how the procedure applies in particu-
lar situations. EPA Region VIII recommends that state/tribal
implementation procedures include such questions and answers
as a means of clarifying the intended approach for addressing
common problems.
> A model antidegradation review worksheet is included to illus-
trate the type of standard form that can be utilized to document
antidegratation review findings. EPA Region VIII recommends
that states and tribes use such forms as a means of simplifying
documentataion requirements and facilitating public participa-
tion and intergovernmental coordination efforts.
1 The federal water quality standards regulation defines the term "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 (see
CFR 131.3).
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CHAPTER 1:
INTRODUCTION
INTRODUCTION
This document has been developed to assist EPA Region VIII
states and Indian tribes with developing the antidegradation policies
and implementation procedures required under the Clean Water Act
(CWA) 303(c) water quality standards program. The document
includes a brief introduction to antidegradation concepts, provides a
Region Vlll-recommended (model) approach to implementing anti-
degradation requirements, identifies key issues that must be
addressed by state and tribal antidegradation programs, presents
background information relevant to antidegradation, and discusses
how a number of antidegradation issues have been addressed by the
states.
What is antidegradation?
An antidegradation policy is one component of a state/tribal
water quality standards regulation. Such policies may apply to any
activity that has the potential to affect existing water quality.
Antidegradation policies are adopted to maintain and protect the
quality of all surface waters, though the level of
protection provided to a specific waterbody
depends upon a number of factors. The highest Antidegradation policies are
level of antidegradation protection, known as tier adopted to maintain and pro-
's, is granted to Outstanding National Resource teetthequaiityoffUlsurface
Waters (ONRWs). These waters typically possess waters*
outstanding ecological or recreational attributes.
Although many such waters have very high water
quality, outstanding water quality as measured by parameters such
as pH and dissolved oxygen is not a prerequisite for designation.
Under antidegradation tier 3, new or increased sources of pollution
that would lower the water quality of an ONRW are not permitted.
The second level of protection, known as tier 2, is provided to waters
(or parameters) where existing water quality exceeds levels neces-
sary to protect fishable/swimmable designated uses (i.e., high quality
waters). Antidegradation maintains and protects the quality of such
waters by specifying the circumstances under which proposed activi-
ties that will lower water quality may be allowed. The basic function
of tier 2 is to ensure that, where degradation is allowed, it is allowed
for a good reason and is minimized in a reasonable manner, subject
to public review. Thus, tier 2 is not intended to be an absolute barri-
er to degradation of water quality but rather a process to carefully
consider whether allowing degradation makes sense.
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Implementation of tier 2 is fundamentally difTerent than implemen-
tation of tier 3 in that degradation may be allowed under tier 2 provid-
ed that a number of specific requirements are satisfied. The most
important function of the tier 2 requirements is to ensure that an
evaluation of alternatives (e.g., source elimination or reduction
options) is conducted. Such an evaluation demonstrates that the
proposed water quality degradation is necessary because reasonable
non-degrading or less-degrading alternatives are not available.
ostimportantfanetion
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an evtduationmustdemon'
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A base level of protection. Known as tier 1. applies
to all surface waters. Under this level of protec-
tion. existing in-stream water uses, and the level
of water quality necessary to protect existing uses,
must be maintained and protected. Such protec-
tion must be afforded whether or not such exist-
ing uses are also designated uses.
A number of states, on their own initiative, have
implemented an extra level of antidegradation
protection. This level, sometimes referred to as a
tier 2.5, provides a level of protection for high
quality waters that is intermediate between tiers 2
and 3. This level of protection differs from state-
to-state, and is not required by, or referenced in,
the federal water quality standards regulation.
Implementation of antidegradation complements the process by
which designated uses and criteria are established and implement-
ed. Antidegradation provides a mechanism to evaluate proposed
activities and to appropriately limit deterioration of existing water
quality. Although the designated uses and criteria are an important
part of the water quality standard for a segment, the baseline for
antidegradation reviews is not the designated uses and criteria, but
rather existing water quality and existing uses. Just as states carefully
review proposed activities to ensure that designated uses and water
quality criteria will be attained, under antidegradation, proposed
activities that would lower existing water quality are carefully
reviewed to ensure that the state antidegradation policy will be satis-
fied. The antidegradation policy is an integral part of a segment's
water quality standards and an urier-utilized tool.
Why has EPA Region Vin developed this antidegradation
guidance?
At this point in time, antidegradation can best be characterized
as an emerging program within EPA Region VIII. For example, sever-
al of the six Region VIII states have not yet fully developed written
procedures for use in implementing their antidegradation policies.
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Not surprisingly, implementation of antidegradation in these states
has not been active or consistent. EPA views such a lack of adequate
antidegradation implementation procedures as a serious deficiency
in state water quality standards programs, and has disapproved sev-
eral states' water quality standards over this issue. The Region
believes that issuing clear guidance will assist these states to estab-
lish effective implementation procedures.
Although several of the Region VIII states have, to varying degrees,
documented implementation procedures for antidegradation, the
Region believes that these existing implementation procedures can
be improved. The Region has recommended chat these states con-
sider additional refinements to their antidegradation procedures.
This guidance includes a number of recommendations that may
assist these states in achieving beneficial improvements to their
existing programs.
Finally, a number of the Indian tribes1 located in Region VIII have
expressed interest in qualifying for the water quality standards pro-
gram and establishing standards pursuant to CWA authority (see 56
FR 64876, December 12. 1991). Because tribal standards programs
will be subject to the same federal requirements as state programs,
such tribes will also need to develop and implement antidegradation
policies and procedures. The model antidegradation procedure
included in this guidance should help tribes to develop effective anti-
degradation implementation procedures.
What are the specific objectives of this guidance?
The specific objectives of this document are:
(1) to provide a model antidegradation implementation procedure
for use by the states and Indian tribes located in EPA Region VIII;
(2) to identify the specific issues that must be addressed and
resolved by state and tribal antidegradation policies and proce-
dures;
(3) to review historical and other background information relative to
antidegradation; and
(4) to characterize the range of approaches used by states to date
on a number of key issues.
1 Consistent with 40 CFR 131.3$, the term "state" in this guidance includes
both states and Indian tribes that administer CWA § 303(c) water quality standards
programs.
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How is this guidance organized?
This chapter of the guidance describes basic antidegradation
concepts, why Region VIII has developed implementation guidance,
and the specific objectives of this document. Chapter 2 presents the
model antidegradation implementation procedure developed by EPA
Region VIII for use by states and tribes. Chapter 3 identifies the pri-
ority issues that must be addressed and resolved by state and tribal
antidegradation procedures to obtain EPA Region VIII approval.
Chapter 4 provides additional discussion of the specific antidegrada-
tion implementation approaches incorporated into the model imple-
mentation procedure. Appendices 1 and 2 present relevant back-
ground information and a review of state implementation approach-
es currendy in use. Finally. Appendix 3 includes EPA Region VIII
responses to major comments and questions received regarding sev-
eral earlier drafts of this guidance.
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CHAPTER 2:
THE MODEL ANTIDEGRADATION
IMPLEMENTATION PROCEDURE1
PARTI. INTRODUCTION
These antidegradation procedures provide detailed methods and
guidance to be followed by the VV^ter Quality Board (the Board) and
the Waiter Quality Division (the Division) in implementing the state
antidegradation policy found at [insert appropriate citation]. In all
cases, applicable technology and water quality-based requirements
are to be implemented in combination with the antidegradation
requirements described in this document.
Implementation of state and federal antidegradation requirements
serves to promote the maintenance and protection of existing sur-
face water quality. Under this program, all "waters of the state" are
provided one of four different levels of antidegradation protection.
The level of protection that is provided to a specific segment
depends upon a number of factors discussed in detail below. At a
minimum, all waters are subject to a base level of protection (known
as tier 1 or existing use protection); some waters
may qualify only for this level of protection.
Antidegradation requirements are triggered when-
ever a regulated activity is proposed that may have
some effect on surface water quality. Such activi-
ties are reviewed to determine, based on the level
of antidegradation protection afforded to the
affected waterbody segment, whether the pro-
posed activity should be authorized.
Mfafesg*mm
Antidegradation require-
ments are triggered when-
ever a regulated activity is
proposed that may have
some effect on surface -water
quality.
This guidance has three principal components. First. Key terms are
defined. Second, the procedures to be followed in completing an
antidegradation review are presented. Finally, a number of questions
and answers are included to further illustrate how these antidegrada-
tion implementation procedures will be applied. A copy of the anti-
degradation worksheet that the Division will use to document review
findings is attached.
1 This chapter of the guidance is intended to provide a recommended exam-
pie of an antidegradation implementation procedure. It includes examples of
each of the types of provisions chat EPA Region VIII considers essential.
Adoption (with or without modification) of this model procedure is recom-
mended by the Region.
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antidegsadatjo*
PART II. DEFINITIONS
An Antidegradation Review is the process by which the state deter-
mines that antidegradation requirements are satisfied for a given reg-
ulated activity that may have some effect on surface water quality.
Assimilative capacity is the increment of water quality (in terms of
concentration), during the appropriate critical condition(s), that is
better than the applicable numeric criterion.
Bioaccumuiative toxic substances are defined as substances with
bioconcentration factors (BCFs) greater than 250.
Bloconcentration Factor (BCF) is the ratio of a substance's concen-
tration in tissue versus its concentration in water, in situations where
the food chain is not exposed or contaminated. For nonmetabolized
substances, it represents equilibrium partitioning between water and
organisms.
Designated use means a use that is specified in water quality stan-
dards as a goal for the waterbody segment, whether or not it is cur-
rently being attained.
Existing use means a use that is actually attained in the waterbody
on or after November 28. 1975, whether or not it is included in the
water quality standards.
High quality water means a waterbody that meets the state's test of
"high quality," which is discussed in paragraphs VI(A)(2) and (3) of
this guidance. In general, waters whose existing quality is better
than necessary to support fishable/swimmable uses will be consid-
ered "high quality."
Outstanding National Resource Water (ONRW) is a waterbody that
has been identified as possessing outstanding ecological or recre-
ational attributes, and has been designated as an ONRW in the state
water quality standards.
Outstanding State Resource Water (OSRW) is a waterbody that has
been identified as possessing outstanding ec ^logical or reci> itional
attributes and has been designated as an OSRW in the state water
quality standards.
Reasonable Alternatives shall be identified based on case-specific
information. Generally speaking, non-degrading or less-degrading
pollution-control alternatives shall be considered reasonable where
the costs of such alternatives are less than 110% of the costs of the
pollution control measures associated with the proposed activity.
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Regulated activity includes any activity that requires a permit or a
water quality certification pursuant to state or federal law (e.g.t CWA
§ 402 NPDES permits, CWA § 404 dredge and fill permits, any activi-
ty requiring a CWA § 401 certification), any activity subject to non-
point source control requirements or regulations, and any activity
which is otherwise subject to state regulations1 that specify that the
antidegradation review process is applicable. For purposes of this
implementation procedure, the term "proposed activity" means a
proposed activity that is also a regulated activity.
Trading means establishing upstream controls to compensate for
new or increased downstream sources, resulting in maintained or
improved water quality at all points, at all times, and for all parame-
ters. Trading may involve point sources, nonpoint sources, or a com-
bination of point and nonpoint sources.
PART III. THE ANTIDEGRADATION REVIEW PROCESS
The Division will conduct some level of antidegradation review
for all regulated activities that have the potential to affect existing
water quality. The specifics of the review will depend upon the
waterbody segment that would be affected, the tier of antidegrada-
tion applicable to that waterbody segment, and the extent to which
existing water quality would be degraded.
The sequence of steps to be completed by the Division in conducting
an antidegradation review is presented in Figure 1. Only major anti-
degradation program requirements are represented in Figure 1. In
conducting an antidegradation review, the first task that will be
addressed by the Division is to determine which tier of antidegrada-
tion applies. This is accomplished, as described in detail below,
based either on the antidegradation designation which has been
assigned to the waterbody (I.e. where such a designation has been
made) or on whether the existing quality of the segment is better
than necessary to support "fishable/swimmable" uses.
Once the correct tier of requirements is identified, the Division deter-
mines whether authorizing the proposed activity would be consistent
1 Such regulations can include the antidegradation policy included in a state's
water quality standards. Using this approach, an antidegradation review may
be required for any and all activities that may affect water quality (i.e., includ-
ing those activities not otherwise subject to control regulations/requirements).
For the sake of clarity, EPA recommends that the activities requiring an anti-
degradation review be discussed in the antidegradation policy or implementa-
tion procedure. Antidegradation procedures should specifically state whether,
and to what extent, activities which would not otherwise be regulated are sub-
ject to antidegradation review requirements (see the discussion of this topic in
Chapter 4 and Appendix 3).
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FIGURE 1
ANTIDEGRADATION IMPLEMENTATION FLOW CHART
TIER 3
Is the proposed activity located on
or upstream of an Outstanding
National Resource Waterbody
(ONRW)?
Ino
Proposed activities may not
result in new/expanded
direct sources; upstream
activities may not lower
water quality of ONRW.
TIER 2.5
Is the proposed activity located on
or upstream of an Outstanding
State Resource Waterbody (OSRW)?
yes
Proposed activities may not
lower existing water quality
of OSRW.
no
no
Has the waterbody been desig-
nated high quality?
Based on available information, does
the segment qualify for tier 2
protection?
TIER 2
TIER 1
no
yes
Will the proposed activity result in
significant degradation? *
lyes
no
Has the applicant demonstrated
that reasonable alternatives to
allowing the degradation do not
exist?
I
Review is terminated for
parameters where signifi-
cant degradation is not
predicted.
no
Deny proposed activity.
yes
Complete tier 2 review requirements. For example, activity may be
authorized if:
• it has socio-economic importance,
• existing uses would be fully protected, and
• state-required controls on point and nonpoint sources have
been achieved.
Activity may be authorized if exist-
ing uses are fully maintained and
protected.
• The likelihood of significant degrada-
tion will be determined on a parameter-
by-parameter basis using appropriate
techniques and based on the significance
factors included in this procedure; note
that the significance test may be by-
passed where reasonable less-degrading
alternatives are clearly available.
8
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with state antidegradation requirements. The major conclusions of
the Division's review are documented using an antidegradation
review worksheet, a copy of which is attached to this implementa-
tion procedure. Based upon the review findings, a preliminary deci-
sion is made by the Division and subjected to intergovernmental
coordination and public participation. Public participation occurs
regardless of the outcome of the preliminary decision (i.e., whether
the proposed activity would be authorized or denied).
The Division then considers public comments and reaches a final
decision regarding whether to authorize the proposed activity pur-
suant to the state antidegradation requirements. The substance and
basis of the final decision by the Division are documented in the
administrative record. Below, the procedures to be followed by the
Division in reaching a preliminary decision under each tier of anti-
degradation are described in detail.
PART IV. TIER 3 PROCEDURES
A. Waters Qualifying for ONRW Protection
(1) Qualification Criteria
Segments will be subject to tier 3 protection requirements only
where an ONRW designation has been assigned by the Board
through the state rulemaking procedures. The factors to be consid-
ered in determining whether to assign an ONRW designation may
include the following: (a) location (e.g., on federal lands such as
national parks, national wilderness areas, or national wildlife
refuges), (b) previous special designations (e.g., wild and scenic
river), (c) existing water quality (e.g., pristine or naturally-occurring),
(d) ecological value1 (e.g.. presence of threatened or endangered
species during one or more life stages), (e) recreational or aesthetic
value (e.g., presence of an outstanding recreational fishery), and (f)
other factors that indicate outstanding ecological or recreational
resource value (e.g., rare or valuable wildlife habitat). Where deter-
mined appropriate, the ONRW designation may be applied to an
entire category of waters (e.g., a wilderness area or areas).
(2^ Water Qualify Requirements
Outstanding water quality is not a prerequisite for ONRW designa-
tion. The only requirement is that the segment have outstanding
value as an aquatic resource, which may derive from the presence of
exceptional scenic or recreational attributes, or from the presence of
1 States should consider ONRW or OSRW designations for segments selected
as reference sites (e.g.. to define biological/ecological integrity for a particular
ecoregion).
-------
unique or sensitive ecosystems that have naturally low water quality
(i.e., as measured by conventional parameters).
Public Nomination
The public may nominate any state water for ONRW protection at
any time by sending a written request to the following address:
Dnsert appropriate address]. The written request should explain why
an ONRW designation is warranted based on one or more of the fac-
tors identified above.
B. Direct Sources to ONKWs
•J.". ^ ""ul ' " ^ "<>» J
• • M' : ¦;¦'¦¦¦ ¦ ^ , \ j-
f Anypropo&e&activitythat
vonM result i m permanent
new or expanded direct
source ofpoUutanta to any
segment which has been. &e*>
ignated as- anONRW is pro-
hibited;
f 1) Prohibition on New or Expanded Snums
Any proposed activity that would result in a perma-
nent new or expanded direct source of pollutants
to any segment which has been designated as an
ONRW is prohibited. This prohibition applies to
new sources, expansion of existing sources in
which treatment levels are maintained, and expan-
sion of existing sources in which treatment levels
are increased to maintain existing pollutant loading
levels. Regardless of effluent quality, any new or
expanded direct source is prohibited.
C. Sources Upstream from ONRWs
fl) No Change in Water Quality Allowed
Any proposed activity that would result in a permanent new or
expanded indirect source of pollutants (i.e., an upstream source) to
an ONRW segment is prohibited except where such source would
have no effect on the existing quality of the downstream ONRW seg-
ment. Effects on ONRW water quality resulting from upstream
sources will be determined based on appropriate techniques and
best professional judgment. Factors that may be considered in judg-
ing whether ONRW quality would be affected include: (a) percent
change in ambient concentrations predicted at the appropriate criti-
cal condition(s), (b) percent change in loadings (i.e., the new or
expanded loadings compared to total existing loadings to the seg-
ment), (c) percent reduction in available assimilative capacity, (d)
nature, persistence, and potential effects of the parameter, (e) poten-
tial for cumulative effects, and (f) degree of confidence in the various
components of any modeling technique utilized (e.g.. degree of con-
fidence associated with the predicted effluent variability).
(2) Trading
A proposed activity that will result in a new or expanded upstream
source may be allowed where the applicant agrees to implement or
-------
finance upstream controls of point or nonpoint sources sufficient to
offset the water quality effects of the proposed activity. Where such
trading occurs upstream of an ONRW segment, tier 3 requirements
will be considered satisfied where the applicant can show that water
quality at all points within the study area will be either maintained
or improved. The Division will document the basis for the trade
through a Total Maximum Daily Load (TMDL) pursuant to CWA §
303(d) requirements. Such TMDLs will include an appropriate mar-
gin of safety. Such a margin of safety will address, in particular, the
uncertainties associated with any proposed nonpoint source con-
trols. as well as variability in effluent quality for point sources. See
definition of trading in Part II.
Information Requirements
The applicant may be required to provide information sufficient to
evaluate the potential effects of the proposed activity on down-
stream ONRWs. The information that will be required in a given situ-
ation will be identified on a case-by-case basis by the Division.
D. Temporary and Limited Effects
m Guidelines
A direct or upstream source that would result in a temporary and
limited effect on ONRW water quality may be authorized. The deci-
sion regarding whether effects will be temporary and limited will be
handled on a case-by-case basis. As a non-binding rule of thumb,
activities with durations less than one month and resulting in less
than a 5 % change in ambient concentration will be deemed to have
temporary and limited effects. Decisions on individual proposed
activities may be based on the following factors: (a) length of time
during which water quality will be lowered, (b) percent change in
ambient concentrations, (c) parameters affected, (d) likelihood for
long-term water quality benefits to the segment (e.g., as may result
from dredging of contaminated sediments), (e) degree to which
achieving applicable water quality standards during the proposed
activity may be at risk, and (f) potential for any residual long-term
influences on existing uses.
PART V. TIER 2.5 PROCEDURES
A. Waters Qualifying for OSRW Protection
m Qualification Criteria
Segments will be subject to tier 2.5 protection requirements only
where an OSRW designation has been assigned by the Board
through the state rulemaking procedures. The factors to be consid-
-------
ered in determining whether to assign an OSRW designation may
include the following: (a) location (eg., on federal lands such as
national parks, national wilderness areas, or national wildlife
refuges), (b) previous special designations (e.g., wild and scenic
river), (c) existing water quality (e.g., pristine or naturally-occurring),
(d) ecological value (e.g., presence of threatened or endangered
species during one or more life stages), (e) recreational or aesthetic
value (e.g., presence of an outstanding recreational fishery), and (f)
other factors that indicate outstanding ecological or recreational
resource value (e.g., rare or valuable wildlife habitat). Where deter-
mined appropriate, the OSRW designation may be applied to an
entire category of waters (e.g., all waters located within a state or
national park).
Thepubtic map nominate a»tf
state waterfor OSRWprotec~
turn at any time via a vrrit~
ten request that explains
why such a designation is
warranted,
(2) Water Quality Requirements
Outstanding water quality is not a prerequisite for
OSRW designation. The only requirement is that
the segment have outstanding value as an aquatic
resource, which may derive from the presence of
exceptional scenic or recreational attributes, or
from the presence of unique or sensitive ecosys-
tems that have naturally low water quality (i.e., as
measured by conventional parameters).
(5^ Public Nomination
The public may nominate any state water for OSRW protection at
any time by sending a written request to the following address:
[insert appropriate address]. The written request should explain why
an OSRW designation is warranted based on one or more of the fac-
tors identified above.
B. Direct and Indirect Sources to OSRWs
M) No Change in Water Quality Allowed
Except as noted below, any proposed activity that would result in a
permanent lowering in OSRW water quality is prohibited. This pro-
cedure applies to direct and indirect (i.e.. upstream) sources of pollu-
tants to OSRWs. The prohibition applies to new sources and expan-
sion of existing sources in which treatment levels are maintair -;d.
Proposed expansions that would also upgrade treatrr :nt levels such
that existing loading levels will be maintained may be authorized.
However, decisions regarding whether to allow new or expanded
sources will be made on a case-by-case basis using appropriate tech-
niques and best professional judgment. Factors that may be consid-
ered in judging whether OSRW quality would be lowered include: (a)
percent change in ambient concentrations predicted at the appropri-
ate critical condition(s), (b) percent change in loadings (i.e., the new
-------
or expanded loadings compared to total existing loadings to the seg-
ment). (c) percent reduction in available assimilative capacity, (d)
nature, persistence, and potential effects of the parameter, (e) poten-
tial for cumulative effects, and (f) degree of confidence in the various
components of any modeling technique utilized (e.g., degree of con-
fidence associated with the predicted effluent variability).
(2) Trading
A proposed activity that will result in a new or expanded source may
also be allowed where the applicant agrees to implement or finance
upstream controls of point or nonpoint sources sufficient to offset
the water quality effects of the proposed activity. Where such trad-
ing occurs on or upstream of an OSRW segment, tier 2.5 require-
ments will be considered satisfied where the applicant can show that
water quality at all points within the study area will be either main-
tained or improved. The Division will document the basis for the
trade through a TMDL pursuant to CWA § 303(d) requirements. Such
TMDLs will include an appropriate margin of safety. Such a margin
of safety will address, in particular, the uncertainties associated with
any proposed nonpoint source controls, as well as variability in efflu-
ent quality for point sources. See definition of trading in Part II.
(3) Information Requirements
The applicant may be required to provide information sufficient to
evaluate the potential effects on downstream OSRWs. The informa-
tion that will be required in a given situation will be identified on a
case-by-case basis.
(4) Exceptions
An exception may be made for permanent new or expanded sources
that, overall, serve to maintain or enhance the value, quality, or use
of the OSRW. Prior to allowing exceptions, the Division shall work
with the project applicant to identify the least-degrading alternative.
For example, a new or expanded source of water treatment facility
effluent associated with a visitor center may be authorized where
reasonable non-degrading or less-degrading treatment alternatives to
allowing a new or expanded source are not available. The Division
shall utilize the procedures included in Part VI(C) to evaluate alterna-
tives. Exceptions will be granted on a case-by-case basis; in general,
exceptions will be granted only where uses will be fully protected
and effects on existing water quality will be minimal.
C. Temporary and Limited Effects
(H Guidelines
Activities that would result in a temporary and limited effect on
OSRW water quality may be authorized. The decision regarding
whether effects will be temporary and limited will be handled on a
rCKAPIt&li.
THEMODEl
PROCEDURE
13
-------
case-by-case basis. As a non-binding rule of thumb, activities with
durations less than one month and resulting in less than a 5%
change in ambient concentration will be deemed to have temporary
and limited effects. Decisions on individual proposed activities may
be based on the following factors: (a) length of time during which
water quality will be lowered, (b) percent change in ambient concen-
trations. (c) parameter affected, (d) likelihood for long-term water
quality benefits to the segment resulting from the proposed activity
(e.g„ as may result from dredging of contaminated sediments), (e)
degree to which achieving applicable water quality standards during
the proposed activity may be at risk, (f) potential for any residual
long-term influences on existing uses, and (g) public use benefits
resulting from the proposed activity (e.g., enhancement or expan-
sion of public access, maintenance of the resource).
PART VI. TIER 2 PROCEDURES
A. Waters Qualifying for Tier 2 Protection
m Two Qualification Mechanisms
Segments may be afforded tier 2 protection by the state in one of
two ways. The first way is for the Board to assign tier 2 protection
through a rulemaking action. Where this occurs, a high quality use
designation will be added to the state standards for the segment.
The sole implication of a high quality designation in the state water
quality control program is that it mandates application of the tier 2
review requirements described below. The second way to afford tier
2 protection is for the Division to make a determination that this
level of protection is warranted during the antidegradation review of
a proposed activity. Such decisions will be based on all relevant
information including any ambient water quality (i.e., physical,
chemical, biological) data submitted by the applicant. The criteria
that will be used in identifying high quality tier 2 waters ar described
below. The same criteria for making the high quality decision apply
regardless of whether the decision is made by rulemaking or during
the Division's antidegradation review. Regardless of how the high
quality decision is made, the same level of protection and the same
procedures are applied.
(2) Qualification Factors
Decisions regarding whether a waterbody is high quality and subject
to tier 2 protection requirements will be based on a best professional
judgment of the overall quality and value of the segment. In general,
waters with existing quality that is better than necessary to support
fishable/swimmable uses will be considered high quality and subject
to tier 2 requirements. The factors that may be considered in deter-
mining whether a segment satisfies the high quality test include the
-------
WwMM&mv.
following: (a) existing aquatic life uses, (b) existing recreational or
aesthetic uses, (c) existing water quality for all parameters (i.e., sub-
ject to the availability of monitoring data or other information for the
segment, upstream segments, or for comparable segments), and (d)
the overall value of the segment from an ecological and public use
perspective. Note that attainment of both aquatic life (fishable) and
recreational (swimmable) uses is not required in order to qualify as a
high quality segment.
(3) Presumptive Applicability
In general, it is presumed that a very large majority of state waters
qualify for tier 2 protection. However, there are some waters in the
state where neither of the CWA fishable/swimma- v,,,..,,;;;
ble goal uses are attained. It is the intent of these
procedures to apply only existing use (tier 1) pro-
tection to such waters. There also may be waters
in the state where one or both of the
fishable/swimmable uses are attained, but exist-
ing water quality is not "better than necessary" to —; —
support the goal uses (i.e., assimilative capacity does not exist for a
number of parameters). It is the intent of these procedures to apply
only existing use (tier 1) protection to such waters provided that
there is no assimilative capacity for each of the parameters to be
affected by the proposed activity.
14) Criteria Exceedences
A difficult question that must be addressed by these procedures is
whether occasional exceedences of one or more narrative or numer-
ic water quality criteria constitute nonattainment sufficient to pre-
clude tier 2 protection. In waters where exceedences have occurred
and continue to occur for one or more parameters, a judgment will
be made based on the factors identified above and in consideration
of information submitted by the applicant and by the public. As a
general operating rule, tier 2 protection will be applied even where
the criteria for some parameters are not always satisfied.
(5) Information Requirements
The applicant may be required to provide monitoring data or other
information about the affected waterbody to help determine the
applicability of tier 2 requirements based on the high quality test. Tht
information that will be required in a given situation will be identified
on a case-by-case basis. Because these procedures presume that tier 2
protection requirements will be applied, such information will typically
be required of the applicant only where this presumption is in dispute.
Such information may include recent ambient chemical, physical, and
biological monitoring data sufficient to characterize, during the appro-
priate critical condition^), the existing uses and the spatial and tempo-
ral variability of existing quality of the segment for the parameters that
would be affected by the proposed activity.
DE|
PftOOOURE
to generate, it is presumed
°f
state waters qualify /or tier
2 protection.
15
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jSft
ANTIDEGIWDATtOK
(6) Charactering Existing Quality
The Division will follow the state procedures used to characterize
existing background quality that are used for purposes of developing
Total Maximum Daily Loads (TMDLs). The characterization of exist-
ing background water quality should appropriately consider spatial
and temporal variability. However, where background water column
data are limited, the Division may conclude that a segment is high
quality and subject to tier 2 protection based on ancillary data such
as land use information, population and demographics, geology,
presence of point or nonpoint sources, dimatological data, or the
health of the aquatic community.
m Public Nomination
The public may nominate any state water for a high quality designa-
tion at any time by sending a written request to the following
address: [insert appropriate address]. The written request should
explain why a high quality designation is warranted based on the
factors identified and discussed in paragraph (2) and (3).
TheDvrisian w0 identify
and eUminatefromfurther
review ority these proposed
activities that present
insignificant threats to
waterqaality. Proposed
activities wUt be considered
significant: and subject to
tier2 requirements where
projectedfor one or more
water qualityparameters.
B. Significant Degradation
m Overview
Once it is determined that tier 2 protection
applies to a waterbody via one of the two decision
mechanisms described above, the next step in the
review process is to determine whether the degra-
dation that will result from the proposed activity
is significant enough to warrant further review
(such as evaluation of alternatives). The factors to
be addressed in judging the significance of the
proposed activity are identified in paragraph (2)
below. Where the significance of the degradation
associated with a proposed activity is in dispute.
— ;—the factors identified in paragraph (2) should also
be the focal point of opposing views by the applicant or the public.
(2) Significance Factors
The likelihood that a proposed activity will pose significant degrada-
tion will be judged by the Division for ml water quality parameters
that would be affected by the proposed activity. Such significance
judgments will be made on a parameter-by-parameter basis. The
Division will identify and eliminate from farther review only those
proposed activities that present insignificant threats to water quality.
Proposed activities will be considered significant and subject to tier 2
requirements where significant degradation is projected for one or
more water quality parameters. Because determinations of signifi-
cant degradation are most appropriately made based on case-specif-
ic information, these procedures do not provide rigid decision crite-
16
-------
ria for judging significant changes in water quality. Rather, signifi-
cant degradation may be demonstrated with respect to any one (or a
combination) of the following factors: (a) percent change in ambient
concentrations predicted at the appropriate critical condition^), (b)
the difference, if any. between existing ambient quality and ambient
quality that would exist if all point sources were discharging at per-
mitted loading rates, (c) percent change in loadings (i.e.. the new or
expanded loadings compared to total existing loadings to the seg-
ment or, for existing facilities only, the proposed permitted loadings
compared to the existing permitted loadings), (d) percent reduction
in available assimilative capacity, (e) nature, persistence, and poten-
tial effects of the parameter, (f) potential for cumulative effects,1 (g)
predicted impacts to aquatic biota, (h) degree of confidence in any
modeling techniques utilized, and (1) the difference, if any. between
permitted and existing effluent quality.
(i) Required Analyses. Based on one or more of the significance
factors identified above, the Division may make determinations
of significant degradation based on appropriate modeling tech-
niques coupled with detailed characterization of the existing
background water quality. However, determinations of signifi-
cance need not be complicated, data-intensive, or resource-
intensive. It is not the intent of these procedures to require
detailed analyses to address each of the factors identified above.
Where appropriate, determinations of significance may be based
on simple analyses. For example, proposed activities may be
judged as insignificant where: (a) available dilution exceeds
100:1, (b) the proposed activity would not result in a significant
increase of loadings for any parameter, or (c) there is substantial
potential for the proposed activity to result in a net long-term
water quality benefit to the segment. Likewise, a significant
increase in loadings for any given parameter may be the basis
for concluding that significant degradation will occur.
(ii) Persistent Toxics. The significance of proposed new or expand-
ed sources of bioaccumulative or other persistent toxic sub-
stances will be judged depending upon, for example, existing
loadings of the substances to the segment from all sources. The
Division's interpretation of monitoring data or other information
1 It is anticipated that most antidegradation reviews will be limited to single
sources; however, where multiple new or expanded sources are likely to be
proposed within a short time period (e.g.. one permit cycle), the Division may
base a determination of significance on the cumulative effect of all the proposed
sources. Where available, a Total Maximum Daily Load (TMDL) analysis will be
used as the basis for the significance determination. Where multiple sources
are deemed significant in a cumulative sense, each individual proposed source
shall be subject to further tier 2 review. Likewise, where multiple loading
increases for a single source occur over time, the cumulative effects of the aim
total increase in loading may be the basis for requiring further tier 2 review.
• v/yAW."
fflAPTEgr
Z Sthsmodcl
PftOCEmjRI
17
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indicating fish tissue or sediment accumulation in the watershed
will be considered with respect to judging the significance of
new or expanded sources of persistent toxic substances.
General Guidelines
As a non-binding rule-of-thumb, proposed activities that would lower
the ambient quality of any parameter by more than 5 %. reduce the
available assimilative capacity by more than 5 %, or increase pollu-
tant loadings to a segment by more than 5 X will be presumed to
pose significant degradation. The intent of this guideline is to estab-
lish a de minimis test of significance and to eliminate from further
review only those proposed activities that will result in truly minor
changes in water quality.
f4) By-passing the Significance Test
Where available information clearly indicates that reasonable non-
degrading or less-degrading alternatives to lowering existing water
quality exist, the Division may by-pass the significant degradation
requirements and direct the applicant to demonstrate the necessity
of the degradation pursuant to Pan VI(C) below.1
(& Trading
The Division may also conclude that a proposed activity will not
pose significant degradation based upon the specifics of any
upstream/downstream trading that has been agreed to by the project
applicant. The Division will document the basis for the trade
through a TMDL pursuant to CWA § 303(d) requirements. Such
TMDLs will include an appropriate margin of safety. Such a margin
of safety will address, in particular, the uncertainties associated with
any proposed nonpoint source controls, as well as variability in efflu-
ent quality for point sources. See definition of trading in Part II.
(6) Information Requirements
The applicant may be required to provide monitoring data or other
information about the affected waterbody and/or proposed activity
to help determine the significance of the proposed degradation for
specific parameters. The information that will be required in a given
situation will be identified on a case-by-case basis. Because these
procedures establish a fairly low threshold of significance, in many
cases a large data base will not be necessary to determine that a pro-
posed activity will result in significant degradation. The information
required may include recent ambient chemical, physical, or biologi-
cal monitoring data sufficient to characterize, during the appropriate
critical condition(s), the spatial and temporal variability of existing
1 By-passing the significance test is an appropriate means of maintaining and
protecting existing water quality even where proposed effects on water quality
may/will be minor.
-------
background quality of the segment for the parameters that would be
affected by the proposed activity, as well as the water quality that
would result if the proposed activity were authorized. State TMDL
procedures for characterizing existing water quality and projecting
future water quality will be the basis for identifying needed informa-
tion and interpreting available data.
(7) Dererminft Significance of Proposed Activity
Activities determined to be significant by the Division shall be sub-
ject to the tier 2 review requirements described below. If the
Division determines that an activity will not pose significant degra-
dation for any parameter, no further antidegradation tier 2 require-
ments shall apply; however, such activities must still meet all tech-
nology and/or water quality based control requirements or condi-
tions of the permit or the water quality certification.
I'M
C. Evaluation of Alternatives to Lowering Water Quality
m Rote of the Division
The primary emphasis of the Division's tier 2 antidegradation
reviews will be to determine whether reasonable non-degrading or
less-degrading alternatives to allowing the proposed degradation are
available. The Division will first evaluate any alternatives analysis
submitted by the applicant for consistency with the minimum
requirements described below. If an acceptable
analysis of alternatives was completed and sub-
mitted to the Division as part of the initial project
proposal, no further evaluation of alternatives will
be required of the applicant. If an acceptable
alternatives analysis has not been completed, the
Division will work with the project applicant to
ensure that an acceptable alternatives analysis is
developed.
(2) Role of the Applicant
The applicant of any proposed activity that would
significantly lower water quality in a high quality segment is required
to prepare an evaluation of alternatives. The evaluation is required,
at a minimum, to provide substantive information pertaining to the
costs and environmental impacts associated with the following alter-
natives: (a) pollution prevention measures' (e.g., substitution of less
toxic substances), (b) reduction in scale of the project, (c) water recy-
cle or reuse, (d) process changes, (e) innovative treatment technology
The primary emphasis of the
Division's tier 2 antidegrar-
datum reviews will be to
determine whether reason-
able nan-degrading or less*
degrading alternatives to
attawingthe proposed degra-
dation are available.
1 For NPDES permits, completing a pollution prevention audit will be consid-
ered an acceptable evaluation of pollution prevention alternatives.
-------
ANTIDe6«ADATK»i
(eg-, land application of wastewater), (f) advanced treatment tech-
nology, (g) seasonal or controlled discharge options to avoid critical
water quality periods, (h) improved operation and maintenance of
existing treatment systems, and (i) alternative discharge locations.
HI Preliminary Determination
Once the Division has determined that feasible alternatives to allow-
ing the degradation have been adequately evaluated, the Division
shall make a preliminary determination regarding whether reason-
able non-degrading or less-degrading alternatives are available This
determination will be based primarily on the alternatives analysis
developed by the project applicant, but may be supplemented with
other information or data. As a non-binding rule of thumb, non-
degrading or less-degrading pollution control alternatives with costs
that are less than 110% of the costs of the pollution control measures
associated with the proposed activity shall be considered reasonable.1
If the Division determines that reasonable alternatives to allowing the
degradation do not exist, the Division shall continue with the tier 2
review and document the substance and basis for that preliminary
determination using the antidegradation review worksheet.
W If Reasonable Alternatives Exist
If the Division makes a preliminary determination that one or more
reasonable alternatives to allowing the degradation exist, the
Division will work with the project applicant to revise the project
design. If a mutually-acceptable resolution cannot be reached, the
Division will document the alternatives analysis findings and public
notice a preliminary decision, based on antidegradation tier 2
requirements, to deny the activity.
(5) Role of Public
Based upon comments and information received during the public
comment period, the Division may reverse its preliminary determi-
nation regarding the availability of reasonable alternatives to allow-
ing the degradation.
0. Determination of Socio-Economic Importance
m Role of the Aopli^nt
The applicant is required to demonstrate the social and economic
importance of the proposed activity. The factors to be addressed in
such a demonstration may include, but are not limited to, the foilow-
1 In evaluating the applicant's evaluation of alternatives, the Division may
rely, in part, on guidance or assistance from EPA Headquarters on the use of
economics in the water quality standards program.
-------
ing: (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 environ-
mental or public health problem.
(2) Role of the Division
Prior to authorizing any proposed activity that would significantly
lower the water quality of a tier 2 water, the Division shall ensure
that the proposed activity will provide important social or economic
development in the area in which the waters are located. In making
a preliminary determination, the Division will rely primarily on the
demonstration made by the applicant. However, the Division may
weigh the applicant's demonstration against counterbalancing socio-
economic costs associated with the proposed activity, such as pro-
jected negative socio-economic effects on the community and the
projected environmental effects (i.e., those determined in the signifi-
cance and/or alternatives analysis decision processes).
a) Additional Information Requirements
Information available to Che Division is not suffi-
cient to make a preliminary determination regard-
ing the socio-economic costs or benefits associat-
ed with the proposed activity, the Division may
require the project applicant to submit specific
items of information needed to support a deter-
mination of importance. The types of information
required of the applicant will be determined on a
case-by-case basis, but may include: (a) informa-
tion pertaining to current aquatic life, recreational,
or other waterbody uses, (b) information neces-
sary to determine the environmental impacts that
may result from the proposed activity, (c) facts
pertaining to the current state of economic devel-
opment in the area (e.g.. population, area employ-
ment. area income, major employers, types of
businesses), (d) government fiscal base, and (e)
land use in the areas surrounding the proposed
activity.
//i'tSrrA V.'V..>.•
It is anticipated thai an
effective mitigation plan
may* in some cases, allow the
state to conclude "impor-
tance* and to authorize pro*
posed activities that could
othervnse not be authorized
pursuant to state antidegrar
datum requirements.
Mitigation plansshotdd
(4) Mitigation
The applicant may voluntarily submit a proposal
to mitigate the adverse environmental effects of
the proposed activity (e.g., in-stream habitat
improvement, bank stabilization/upgraded ripari-
an vegetation). Such mitigation plans should
describe the proposed mitigation measures and the costs of such
mitigation. Such a mitigation plan will not release the Division from
its obligation to require any reasonable non-degrading or less-
degrading alternatives under Part VI(C) of this procedure, nor will
mining success of the miti-
gation^ legal commitment for
fottow»up monitoring and
additional work (if neces~
saty)* and: where practicable,
a commitment to implement
the mitigation before the
project and water quality
degradationare allowed.
21
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EMIKGlOiiVlft
AWlDfGHADATtOR
^£
such plans have any effect on the effluent limitations to be included
in any NPDES permit (except possibly where a previously-completed
mitigation project has resulted in an improvement in background
water quality that afFects the water quality-based limit). Such mitiga-
tion plans will be developed and implemented by the applicant as a
means to further minimize the environmental effects of the pro-
posed activity and to increase its socio-economic importance. It is
anticipated that an effective mitigation plan may, in some cases,
allow the state to conclude "importance" and to authorize proposed
activities that could otherwise not be authorized pursuant to state
antidegradation requirements. Mitigation plans should include crite-
ria for determining success of the mitigation, legal commitment for
follow-up monitoring and additional work (if necessary), and where
practicable, a commitment to implement the mitigation before the
project and water quality degradation are allowed.
(5^ Preliminary nerermination
Once the Division has reviewed available information pertaining to
the socio-economic importance of the proposed activity, che Division
shall make a preliminary determination regarding importance.1 If
the Division determines that the proposed activity has social or eco-
nomic importance in the area in which the affected waters are locat-
ed. the Division shall continue with the tier 2 review and document
the substance and basis for that preliminary determination using the
antidegradation review worksheet.
(6) If Importance is Found Lacking
If the Division makes a preliminary determination that the proposed
activity does not have social or economic importance in the area in
which the affected waters are located, the Division will document
that antidegradation review finding and public notice a preliminary
decision, based upon antidegradation tier 2 requirements, to deny
the proposed activity.
(7) Role of Public
Because the socio-economic importance of a proposed activity is a
question best addressed by local interests, the Division will give par-
ticular weight to the comments submitted by local governments,
land use planning authorities, and other local interests in determin-
ing whether fhe balancing of benefits and costs that was the basis
for the Division's preliminary decision was appropriate. Based upon
comments and information received during the public comment
period, the Division may reverse its preliminary determination
regarding the social or economic importance of a proposed activity.
1 In evaluating the applicant's demonstration of socio-economic importance,
the Division may rely, in part, on guidance or assistance from EPA
Headquarters on the use of economics in the water quality standards program.
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E. Ensure Full Protection of Existing Uses
m See Part VII Tier t Procedures
Prior to authorizing any proposed activity that would significantly
degrade a tier 2 water, the Division shall ensure that existing uses
will be fully protected consistent with the tier 1 implementation pro-
cedures provided below.
% Ms
- ' THfMODEi
F. Ensure Implementation of State-Required Point and
Nonpoint Source Controls
(1) Role Of fhft Division
Prior to authorizing any proposed activity that would significantly
degrade a tier 2 water, the Division shall determine that compliance
with state-required controls on all point and nonpoint sources in the
zone of influence1 has been assured. The Division may conclude
that such compliance has not been assured where facilities are in
noncompliance with their NPDES permit limits. However, the exis-
tence of schedules of compliance for purposes of NPDES permit
requirements will be taken into consideration in such cases. Where
there are nonpoint sources that are regulated activities, the Division
shall determine that any state-required controls or best management
practices have been achieved or that a plan that assures such compli-
ance has been developed.
(2) Preliminary Determination
Based upon available data or other information, the Division will
make a preliminary determination regarding whether compliance
with state-required controls on point and nonpoint sources in the
zone of influence has been assured. If the preliminary determina-
tion is that such compliance has been assured, the Division shall
continue with the tier 2 review and document the substance and
basis for that preliminary determination using the antidegradation
review worksheet.
H) If Controls have nnr been Achieved
If the Division makes a preliminary determination that compliance
with state-required point and nonpoint source controls has not been
assured, the Division shall document that antidegradation review
finding and public notice a preliminary decision, based upon tier 2
requirements, to deny the proposed activity.
1 The zone of influence extends upstream and downstream as appropriate for the
parameterfwaterbody under consideration. Another acceptable approach would
be to limit application to chose point/nonpoint sources located on the segment.
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AWlDSGtADATlOH
(4) Role of Public
Based upon comments and information received during the public
comment period, the Division may reverse its preliminary finding
regarding the degree to which compliance with state-required point
and nonpoint source controls has been assured.
PART VII. TIER 1 PROCEDURES
A. Waters Qualifying for Tier 1 Protection
m Warere Subject rn Tier 1 Refluirempnrs
All waters are subject to tier 1 protection. Those which are only sub-
ject to tier 1 protection are those waters that have not been assigned
an ONRW, OSRW, or high quality antidegradation designation by the
Board and that do not currendy possess the overall water quality or
value necessary to meet the high quality test (see Section VI(A) of
this implementation guidance). In general, tier 1-oniy waters are
those segments where fishable/swimmable goal uses are not
attained, or where assimilative capacity does not exist for any of the
parameters that would be affected by the proposed activity.
B. Two-Part Requirement
(1) Protect Water Quality and Uses
The state antidegradation policy requires that existing uses, and the
water quality necessary to protect existing uses, shall be maintained
and protected. This requirement contains two parts: (1) protection
of existing uses, and (2) protection of the water quality necessary to
maintain and protect existing uses.
C. Ensure Water Quality Necessary to Maintain and Protect
Existing Uses
rn Confirm that Designated Uses Address Existing Uses
Prior to authorizing any proposed activity, the Division shall ensure
that water quality sufficient to protect existing uses fully will be
achieved. An :mportant decision that must be made by the Division
is whether the waterbody currently supports, or has supported since
November 28, 1975, an existing use that has more stringent water
quality requirements than the currently designated uses. In making
this decision, the Division will focus on whether a higher designated
use (i.e., based on the state use designations) should be assigned to
the waterbody to reflect an existing use. Where the Division deter-
mines that the currently designated uses appropriately reflect the
existing waterbody uses, the Division shall document that prelimi-
-------
nary determination using the antidegradation review worksheet (see
page 35). In such cases, the water quality control requirements nec-
essary to protect designated uses will be presumed to also fully pro-
tea existing uses.
(2) Where Designated Uses do not Address Existing Uses
The procedure oudined in paragraph (1) above presumes that desig-
nated uses appropriately address existing uses pursuant to state and
federal requirements. Where this is noc the case, a revision to state
standards may be needed because, pursuant to the state and federal
water quality standards regulations, designated uses are required to
reflect, at a minimum, all attainable (including currently attained, or
existing) uses. Where existing uses with more
stringent protection requirements than currently
designated uses are identified, the Division will
ensure levels of water quality necessary to protect
existing uses fully and. at the earliest opportunity,
propose that appropriate revisions to the designat-
ed uses be adopted into the state water quality
standards. However, the Division wiil not delay tier
1 protection pending the reclassification action.
THE MODEL
fv' PROCEDURE
(3) Require Water Quality Necessary rn Protect
Existing Uses
Where the Division determines that the water-
body currently supports, or has supported since
November 28, 1975, an existing use that has
more stringent water quality requirements than
the currently designated uses, the Division shall
identify the level of water quality necessary to
protect existing uses fully for the parameters in question. The
Division's estimate of the level of water quality required will be
based on numeric state water quality criteria, narrative state criteria,
and/or federal criteria guidance. In general, water quality sufficient
to maintain and protect existing uses for the parameters in question
will be assured using the same procedures that would have been fol-
lowed had the water quality standards (i.e., uses and criteria) been
appropriately assigned to begin with. The preliminary findings
regarding existing uses and the level of water quality necessary to
protect existing uses will be documented using the antidegradation
review worksheet.
A proposed activity that will result in a new or expanded source may
also be allowed where the applicant agrees to implement or finance
upstream controls of point or nonpoint sources sufficient to offset
the water quality effects of the proposed activity. Where such trad-
ing occurs, tier 1 requirements will be considered satisfied where the
Wh^existmguses with
more stringent protection
requirements than currently
designated uses are identic
fxed* the Division wilt ensure
tevels of water quality neces-
sary to protect existing uses
Jfrdty and* at the earliest
opportunity propose that
appropriate revisions to the
designated uses he adopted
into the state water quality
standards*
25
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applicant can show that the level of water quality necessary to pro-
tea existing uses fully will be achieved. The Division will document
the basis for the trade through a TMDL pursuant to CWA §' 303(d)
requirements. Such TMDLs will include an appropriate margin of
safety. Such a margin of safety will address, in particular, the uncer-
tainties associated with any proposed nonpoint source controls, as
well as variability in effluent quality for point sources. See definition
of trading in Part II.
(5) Additional Information Retirements
The applicant may be required to provide monitoring data or other
information about the affected waterbody to help determine
whether designated uses also re flea existing waterbody uses or the
level of water quality necessary to protect existing uses fully. The
information that will be required in a given situation will be identi-
fied on a case-by-case basis. Because these procedures presume that
designated uses re flea existing uses, such information will typically
be required only where this presumption is in doubt, based on the
information available to the Division. Where this presumption is in
doubt, the applicant may be required to provide physical, chemical,
or biological monitoring data or other information needed by the
Division to identify and protect existing uses.
D. Ensure Full Protection of Existing Uses
n 1 Presume that Applirahle Criteria Will Protect Existing Uses
The procedure just discussed presumes that implementation of the
water quality criteria established to protect designated uses will also
incidentally protect existing uses. However, situations may arise
where a proposed (regulated) activity will impair or eliminate an
existing use for reasons which cannot be tied to any applicable water
quality criterion (e.g., impacts to aquatic life habitat that may result
from the discharge of "dean" sediment).
(2) Where Applicable Criteria Will Not Protect Existing Uses
Where the Division concludes that existing uses will be impaired by
a regulated activity for reasons which cannot be tied to the applica-
ble criteria, the Division will work with the projea applicant to revise
the project design such that existing uses will be maintained and
protected. If a mutually-acceptable resolution cannot be achieved,
tie Division will document the basis for its preliminary determina-
tion regarding the loss or impairment of existing uses that will occur
using the antidegradation review worksheet, identify appropriate
control requirements, up to and including denial of the proposed
activity, and public notice its preliminary decision.' Where possible.
1 Note chat only regulated activities are addressed by these procedures (e.g.,
discharge of a pollutant that may have a physical effect not addressed by water
quality criteria).
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such effects will be predicted based upon quantitative methods. In
predicting effects, the Division will use all information submitted by
the applicant, available modeling techniques, and best professional
judgment based upon experience with similar types of projects, as
appropriate.
Where Loss or Impairment of Existing Uses is Not Predicted
Where the Division determines that implementation of the applica-
ble water quality criteria will fully protect the existing uses, that find-
ing will be documented using the antidegradation review worksheet.
.v.v.'tfw -1^
iT-'imtiobEL •
PROCEDURE
¦/WW
PART VIII. DOCUMENTATION, PUBUC REVIEW, AND
INTERGOVERNMENTAL COORDINATION PROCEDURES
A. Documentation of Antidegradation Review Findings
f 1) Antidegradation Worksheet
The Division will complete an antidegradation review for all pro-
posed regulated activities that may have some effect on surface
water quality. The findings of all antidegradation reviews will be
documented using an antidegradation worksheet, a copy of which is
attached to this guidance (see page 35).
B. Public Review Procedures
(1) Follow State Requirements
The antidegradation review findings will be subjected to the state
public participation requirements found at [insert appropriate refer-
ence]. A separate public notice for purposes of antidegradation need
not be issued. For example, the antidegradation preliminary find-
ings may be included in the public notice issued for purposes of an
NPDES permit/§ 401 certification,
(2) Content of Public Notice
In preparing a public notice, the Division will, at a minimum: (a) out-
line the substance and basis of the state's antidegradation review
conclusions, including the preliminary finding regarding whether to
authorize the proposed activity, (b) request public input on particular
aspects of the antidegradation review that might be improved based
on public input (e.g.t existing uses of the waterbody by the public,
the preliminary determination on socio-economic importance), (c)
provide notice of the availability of the antidegradation review work-
sheet, (d) provide notice of the availability of any introductory public
information regarding the state antidegradation program, and (e)
include a reference to the state antidegradation policy.
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EPABEGIONV1
©
xyiv.,
C. Intergovernmental Coordination Procedures
m Follow State rpp
The Division shall conduct all antidegradation reviews consistent
with the intergovernmental coordination procedures included in the
state's continuing planning process.
(2) Minimum Process
At a minimum, the Division will provide copies of the completed
antidegradation review worksheet and/or the public notice to appro-
priate state and federal government agencies along with a written
request to provide comments by the public comment deadline.
PART IX. QUESTIONS AND ANSWERS
The following questions and answers are intended to provide
additional explanation regarding how the Board and the Division will
implement [he state antidegradation policy.
Tier 3 Questions
A proposed expansion of a municipal point source discharge is locat-
ed 20 miles upstream of an ONRW segment boundary. Under what
circumstances would the expanded discharge be allowed?
Pursuant to tier 3 requirements, a new or expanded upstream source
may be allowed only where it would have no effect on the water
quality of the downstream ONRW segment. The Division would pre-
dict effects on the water quality of the downstream ONRW segment
for appropriate parameters using appropriate techniques. Where
necessary, the applicant may be required to provide monitoring data
to support model development, calibration, and/or validation.
Unless the expanded portion of the discharge is expected to contain
persistent toxics, it is possible that the discharge can be allowed
because of dilution, fate, and transport processes that would occur
within the 20 stream miles. If the proposed discharge would not
affect the quality of the ONRW. the proposed activity would still be
subject to tier 2 or tier 1 requirements applicable to the receiving
water segment.
Tier 2.5 Questions
A proposed expansion of an industrial point source discharge would
discharge direcdy into an OSRW segment. The effluent is expected
to contain bioaccumulative toxics. Can the expanded discharge be
allowed?
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Yes, under certain circumstances. Pursuant to tier 2.5 requirements,
a new or expanded source may be allowed provided that it would
have no effect on the water quality of the OSRW (i.e., effluent quality
at or better than background quality). The Division would predict
effects on the water quality of the OSRW segment for appropriate
parameters using appropriate techniques. Since the discharge would
increase mass loadings of bioaccumulative toxics, an important con-
sideration is the extent of any existing accumulation of such toxics in
fish tissue and sediment.
Construction of a state park visitor's center has been proposed adja-
cent to an OSRW segment. The center would provide Park visitors
with information and a parking lot. A small treatment facility is pro-
posed to handle the wastewater effluent that would result from the
visitors center. Effluent from the treatment facility would be dis-
charged directly into the OSRW segment. Can the discharge be
allowed?
The antidegradation tier 2.5 procedure includes a prohibition of any
permanent new source of pollutants that would lower the quality of
an OSRW segment. However, pursuant to Part V(B)(4) of the imple-
mentation procedure; the Division may allow exceptions to this pro-
hibition where the proposed activity would serve to "maintain or
enhance the value, quality, or use" of the OSRW segment. Because a
visitor's center certainly would enhance public access and use, the
Division would first work with the project applicant to determine if
there are reasonable alternatives to establishing a new point source
discharge. Depending on the specific circumstances, it is possible
that such a discharge could be allowed.
Tier 2 Questions
A new point source discharge is proposed to a segment which meets
the high quality test. The NPDES permit would include only technol-
ogy-based limits which, it has been determined, will be adequate to
achieve all water quality criteria and protect the designated uses. Is
an antidegradation review required?
Yes. Under the antidegradation procedure, an antidegradation
review is required for all "regulated activities" which includes, for
example, activities requiring an NPDES permit. The fact that water
quality-based limits are not required is irrelevant. The antidegrada-
tion review is required to ensure that, for example, the availability of
any reasonable non-degrading or less-degrading alternatives is evalu-
ated. Whenever an NPDES permit is issued, an antidegradation
review worksheet must be completed by the Division to document
llffiMtOCBMIK
29
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the fact that antidegradation requirements were determined to be
satisfied.
A proposed discharge would significantly degrade existing water
quality for dissolved oxygen and ammonia. Background concentra-
tions of dissolved oxygen and ammonia are currendy better than the
applicable aquatic life criteria for these parameters. Although an
aquatic life designated use has been assigned to the receiving water
segment, historical mining practices have resulted in high ambient
levels of copper, zinc and cadmium. These heavy metals would not
be included in the proposed discharge. However, as a result of these
high metals concentrations, the biological health of the receiving seg-
ment is very severely limited such that "fishable" conditions are not
currently achieved. Is the segment a high quality water subject to
tier 2 requirements?
No. The state will not apply tier 2 requirements to segments where
water quality is not better than necessary to support fishable/swim-
mable uses. Even though assimilative capacity exists for the para-
meters in question, the historical pollution sources are currently pre-
cluding attainment of a fishable aquatic life use Although the state
presumes that most waters are high quality and subject to tier 2 pro-
tection, in this case the overall quality and value of the segment is
not sufficient to warrant application of tier 2. However, a proposed
municipal discharge to the same segment could be subject to tier 2
requirements (for purposes of bacteriological quality requirements) if
existing water quality is better than necessary to support "swimma-
ble" uses.
A new point source discharge is proposed on a segment for which
very little ambient monitoring data is currendy available. Based on
limited upstream monitoring data, land use information, absence of
other known point sources, and the magnitude of the proposed dis-
charge, the Division believes that the segment meets the high quality
test described in Part VI(A) of these procedures and that significant
degradation of existing water quality will result. Accordingly, the
Division asks the project applicant to evaluate alternatives to lower-
ing water quality. However, the project applicant believes that the
segment is not a high quality water and asks the Division the folic m-
ing question: "What do we have to do to show you that the segment
is not a high quality water?"
Consistent with Part VI(A) of these procedures, the applicant must
show either that: (1) neither of the CWA fishable/swimmable goal
uses are attained, or (2) fishable/swimmable uses are attained, but
there is no assimilative capacity for any of the parameters to be
affected by the proposed discharge (i.e., water quality is not "better
-------
than necessary" to support fishable/swimmable uses). One of these
showings must be made with appropriate physical, chemical and/or
biological data, taking into account spatial and temporal variability.
The amount of sampling and locations for sampling would be deter-
mined on a case-by-case basis. Sampling should be conducted to
characterize, during the appropriate critical condition^). the existing
uses and existing water quality of the segment. In general, the moni-
toring plan should be clearly defined by the applicant in consultation
with the Division prior to any field work. The applicant would be
responsible for the costs of field monitoring and laboratory analysis.
A proposed activity would increase the ambient concentrations for
several metals in a high quality segment. A number of upstream
point sources are discharging only a fraction of the total loadings for
these same metals that their permits authorize. How would the
Division go about determining whether the proposed degradation is
significant enough to warrant further tier 2 review?
The Division's analysis might look at several considerations. In all
likelihood, the Division would examine the extent to which available
assimilative capacity would be reduced. Typically, assimilative
capacity is defined as the difference between the water quality crite-
ria and the existing ambient background quality for the parameters
in question. In this case, however, the Division would look at assim-
ilative capacity as the difference between the water quality criteria
and the ambient quality that would exist if all point sources were dis-
charging at their permitted loading rates. Establishing such a base-
line is necessary in order to get a true picture of the remaining
assimilative capacity in the segment.
Where an existing facility's effluent quality is better than the NPDES
permit requires, and the permit comes up for renewal, should reissu-
ing the same permit be considered significant degradation?
Yes, in some cases. One of the factors included in the state's imple-
mentation procedure to help determine significant degradation is:
"the difference, if any, between permitted and existing effluent quali-
ty." This factor has been included to address situations where a facil-
ity's existing effluent quality is substantially better than what the
permit authorizes. In such situations, and particularly where the
parameters in question are of concern (such as may be the case for
persistent toxic substances that have accumulated in fish or sedi-
ments), it may be necessary to subject such re-issued permits to fur-
ther antidegradation reviews, including an evaluation of alternatives.
The result of such review may be a re-issued permit with limits that
reflect existing effluent quality. Such review may also reveal that rea-
chapter?
v.w.
©
31
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sonable pollution-prevention alternatives are available that would
result in complete elimination of the parameters of concern from the
facility's effluent. Thus, there will be situations where reissuing the
same permit will be considered significant degradation and subject-
ed to fUrther antidegradation review.
A proposed activity would result in a significant new source of pollu-
tants to a high quality segment. The effluent quality for the pro-
posed source would satisfy all technology and water quality (criteria)-
based effluent requirements. However, the alternatives analysis
demonstrates that a reasonable non-degrading alternative is avail-
able. Does antidegradation require that the non-degrading alterna-
tive be implemented?
Yes. The proposed activity could only be authorized if it were modi-
fied to implement the non-degrading alternative. In this case, simply
satisfying the technology and water quality-based effluent require-
ments is not adequate because a reasonable alternative is available
that will better maintain and protect existing water quality.
Because of a lack of background water quality data, it is unclear to
what extent a proposed activity on a high quality segment would
change ambient concentrations of several parameters. However, the
Division believes that a less-degrading alternative is clearly available.
How would the Division proceed?
In this case, predicting the effect of the proposed activity on ambient
water quality may not be critical from an antidegradation perspective.
Because the primary function of the tier 2 procedures is to require
any reasonable non-degrading or less-degrading alternatives, and
such an alternative is clearly available in this case, the Division would
likely "by-pass" the significance finding (consistent with Section
VI(B)(4) of this implementation guidance) and proceed to the necessi-
ty of degradation finding. Although quantifying background concen-
trations of the parameters in question would be needed to derive a
water quality based effluent limit (WQBEL) or Total Maximum Daily
Load (TMDL), it may not be critical from an antidegradation perspec-
tive. Where additional ambient data is needed for purposes of
WQBEL calculation (or perhaps to support a finding of importance),
the Division would likely require the project applicant to provide the
needed data. In general, the water quality data and procedures used
to establish a Total Maximum Daily Load (TMDL) will be adequate to
answer pertinent antidegradation questions.
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Tier 1 Questions
A project has been proposed chat requires a CWA § 404 dredge and
fill permit. The project would result in fill material being placed in a
wetland which is protected as a surface water of the state, eliminat-
ing the existing uses in the Riled area. Considering the state anti-
degradation requirements under tier 1, can a CWA § 404 permit and
a state § 401 water quality certification be issued?
EPA guidance states that, since a literal interpretation of the anti-
degradation policy could result in preventing the issuance of any
wetland fill permit under CWA § 404, and it is logical to assume that
Congress intended some such permits to be granted within the
framework of the Act, existing uses will be deemed protected with
regard to fills in wedands if the discharge would not result in "signifi-
cant degradation" to the aquatic ecosystem as defined under §
230.10(c) of the § 404(b)(1) guidelines.1 The state intends to apply
this EPA guidance in most cases. However, EPA guidance does not
affect the state's authority, pursuant to CWA § 401 and state anti-
degradation requirements, to condition or deny water quality certifi-
cations where a wetland fill project would result in loss or impair-
ment of existing uses. Although state certifications for § 404 permits
have been and will continue to be issued where appropriate, the
state is not bound by EPA guidance with respect to interpretation of
state existing use protection requirements. Further. EPA has encour-
aged states to utilize the CWA § 401 certification process and state
antidegradation requirements as a valuable tool for influencing CWA
§ 404 permit decisions.2
A new industrial discharge is proposed to a waterbody which only
qualifies for tier 1 protection. Although the segment has not been
assigned any aquatic life designated uses, a citizens group has sub-
mitted information indicating that the segment supports a communi-
ty of certain nongame fish species and a variety of pollution-sensi-
tive macroinvertebrate species. Does antidegradation require that
the proposed discharge maintain water quality necessary to support
the existing aquatic life use, even though no aquatic life use is desig-
nated?
1 See Questions and Answers on: Antidegradation. U.S. Environmental
Protection Agency, August, 1986.
2 See Wetlands and 401 Certification. Opportunities and Guidelines Jar States and
Eligible Indian Tribes. U.S. Environmental Protection Agency, April. 1989.
Vr\V/"A
jiiODiEfr
33
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Yes. The Division would examine the information submitted by the
citizens group, any other available information such as data that the
applicant has been required to submit, and make a determination
regarding the existing aquatic life use and the level of water quality
necessary to support that aquatic life use. If an existing aquatic life
use is identified, and prior to authorizing the new discharge, the
Division is required under antidegradation requirements to ensure
that the point source control requirements will fully pro tea the iden-
tified aquatic life use, regardless of whether that use has been desig-
nated. A change in the state water quality standards, to upgrade the
designated use, is not required to protect the existing use. However,
at the earliest opportunity the state would initiate a rulemaking to
appropriately revise the designated uses for the segment.
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ANTIDEGRADAHON REVIEW WORKSHEET
1. Name of Reviewer.
Name of Receiving Water.
Basin:
Segment No.: —
Stream Classification:
Other:
2. Brief description of Proposed Activity:
ID Number, if any:
3. Which tier(s) of antidegradation apply?
~ Tier3 - go to question 4
[ [ Tier 2.5 - go to question 7
| | Tier 2 - go to question 10
| | Tier 1 - go to question 16
Tier 3 Questions
4. Will the proposed activity result in a permanent new or expanded
source of pollutants directly to an ONRW segment?
¦ ~ yes - recommend denial of proposed activity.
no
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5. If the proposed activity will result in a permanent new or
expanded source of pollutants to a segment upstream from an
ONRW segment, will the proposed activity affect ONRW water
quality (see IV(Q(l) of the implementation procedure)?
Basis for conclusion:
6. If the proposed activity will result in a non-permanent new or
expanded source of pollutants to an ONRW segment or a seg-
ment upstream from an ONRW segment, will the proposed
activity result in "temporary and limited" effects on ONRW
water quality (see IV(D)(1) of the implementation procedure)?
Basis for conclusion:
Tier 2.5 Questions
7. If the proposed activity will result in a permanent new or
expanded source of pollutants directly to an OSRW segment or
a segment upstream from an OSRW segment, will the proposed
activity affect OSRW water quality (see V(B)(1) of the implemen-
tation procedure)?
yes - recommend denial of proposed activity
no
yes
no - recommend denial of proposed activity
yes - recommend denial of proposed activity.
no
Basis for conclusion:
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OMPTEK2
THi MODEL
PROCIDURE
8. Should the new or expanded permanent source of pollutants
that will affect water quality be authorized because, overall, it
will serve to maintain or enhance the value, quality, or use of
the OSRW (see V(B)(4) of the implementation procedure)?
~ no - recommend denial of proposed activity
Basis for conclusion:
9. If the proposed activity will result in a non-permanent new or
expanded source of loadings to an OSRW segment or a segment
upstream from an OSRW segment, will the proposed activity
result in "temporary and limited" effects on OSRW water quality
(see V(C)(1) of the implementation procedure)?
Basis for conclusion:
Tier 2 Questions
10. Does the waterbody qualify for tier 2 protection as a result of a
High Quality use designation by the Board (see VI(A) of the
implementation procedure)?
yes
| | yes
no - recommend denial of proposed activity
yes
no
If no. basis for conclusion that tier 2 applies:
-------
EPA REGION VI
11. Will the proposed activity result in significant degradation (see
VI(B) of the implementation procedure)?
~ j«
~ no - recommend approval of the proposed activity
~ significance test by-passed due to availability of a rea-
sonable less degrading alternative
If significance test not by-passed, basis for conclusion:
12. Has the applicant completed an adequate evaluation of alterna-
tives and demonstrated that there are not reasonable alterna-
tives to allowing the degradation (see VI(Q of the implementa-
tion procedure)?
| | yes
~ no - recommend denial of the proposed activity
If no, basis for conclusion:
13. Has the applicant demonstrated that the proposed activity will
provide important socio-economic development in the area in
which the affected waters are located (see VI(D) of the imple-
mentation procedure)?
| | yes
~ no - recommend denial of the proposed activity
If no, basis for conclusion:
14. Will existing uses be fully protected consistent with the Tier 1
procedures oudined by questions 17-19 below (questions 17-19
must be completed)?
~
~
yes
no - recommend denial of the proposed activity
-------
15. Have all state-required controls on point and nonpoint sources to
the segment been achieved (see VI(F) of the implementation
procedure)?
Basis for conclusion:
Tier 1 Questions
16. The basis for concluding that tier 2 requirements do not apply is
as follows (see VII(A)(1) of the implementation procedure):
17. Are there uses that exist or have existed since November 28,
1975 that have more stringent water quality protection require-
ments than the currently designated uses (see VII(C) of the
implementation procedure)?
If yes, basis for conclusion:
18. If the answer to question 17 was yes, what water quality criteria
requirements will ensure protection of such existing uses (see
VIKQ of the implementation procedure)?
(Indicate parameters and applicable water quality criteria.)
yes
no - recommend denial of the proposed activity
yes
no
-------
. X;Iw y/w>
19. Will existing uses be fully maintained and protected (see VII(D)
of the implementation procedure)?
~ V
| | no - recommend denial of the proposed activity
If no, basis for conclusion:
Preliminary Decision
20. Based on the above, can the proposed activity be authorized
pursuant to the state antidegradation policy?
| | ¦ yes
~ no
Basis for conclusion:
Signature:
Date:
-------
CHAPTER 3:
PRIORITY ISSUES
chapis*?
Mill*
What is Region VIITs Bottom Line?
The federal water quality standards regulation at 40 CFR 131.12
establishes certain minimum requirements applicable to state anti-
degradation programs (see Appendix 1). All EPA Region VIII state
antidegradation policies and implementation procedures must be
consistent with these minimum federal regulatory requirements.
In general, the primary federal antidegradation requirement that has
not yet been fully addressed by Region VIII states is development (or
further refinement) of antidegradation implementation procedures.
Because EPA Region VIII must ensure that such tt-—^—-
state antidegradation procedures are sufficiently
developed to promote effective implementation,
below are listed the issues that must be addressed
and clearly resolved by such procedures to obtain
EPA Region VIII approval.
Because EPA. Region vm
must ensure that such state
antidegradation procedures
are: sufficiently developed to
The Region believes that identifying these "bot-
tom line" issues will assist states and tribes by
providing clear direction regarding the questions
that must be resolved by state antidegradation
procedures. For each of the issues, there is a
range of approaches that would be acceptable to
the Region. The approach that EPA Region VIII
recommends is incorporated into the model ~
implementation procedure found in Chapter 2. To minimize the
potential for Regional disapproval of a state antidegradation proce-
dure, EPA Region VIII encourages states that are interested in deviat-
ing from the Region's recommended approach to work closely with
the Region at the staff level throughout the development process.
EPA Region VIII recommends that states base their implementation
procedures on the model procedure included in Chapter 2.
In summary, EPA Region VIII will review and approve state anti-
degradation policies and procedures provided that they are consis-
tent with federal antidegradation requirements and they establish clear
and reasonable procedures and guidelines that will promote consis-
tent implementation on each of the issues listed in this chapter.
tation* below are listed the
issatxsthatimxsthe
resolved by such procedures
to obtain EPA Regum VUI
approval* Jy-
-------
What are the issues that must be addressed?
General Issues Under All Three Tiers
1) What activities or types of activities are subject to antidegrada-
tion review requirements?1
2) How will public participation and intergovernmental coordina-
tion be achieved?
3) What specific items will be addressed in the public notices asso-
ciated with antidegradation review preliminary decisions?
4) How will antidegradation review findings be documented?
5) What information is/may be required of the project applicant?2
Tier 3 Issues
6) What are the qualification requirements and procedures for
ONRW or tier 3 designation?
7) What are the procedures by which the public can nominate a
specific waterbody for ONRW designation?
8) What requirements apply to proposed new or expanded sources
to ONRWs (state/tribal procedures must address both sources
located on upstream segments and sources directly affecting
ONRW segments)?
9) What types of limited and temporary impacts to ONRWs. if any.
may be authorized, and what guidelines will be applied to identi-
fy the activities resulting in, or not resulting in, such impacts?
1 At a minimum. Region V!!! states must establish antidegradation implemen-
tation procedures that require completion of an antidegradation review for ail
currently regulated activities (see definition of "regulated activity" in Chapter
2). "Antidegradation reviews" are conducted under all three tiers of antidegra-
dation, although the level of review required depends upon which tiers apply
and other factors. States are encouraged to apply antidegradation broadly to
address the variety of actions that may degrade water quality (i.e., point and
nonpoint sources).
2 This is an issue that should be addressed separately for each tier of anti-
degradation.
-------
Tier 2 Issues
' ?* :
£?; /fe/'vw-
priority issues
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r?", y~y, -Sf, * 'ft fs* "y'
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10) What criteria will be used to identify high quality waters (e.g.t
will a waterbody-by-waterbody or parameter-by-parameter
approach be used)?
11) What process will be followed to identify high quality waters
(e.g.. will such decisions be made in advance via rulemaking or
on an ad hoc basis once an activity is proposed)?1
12) How does the state define the terms "degradation" or "signifi-
cant degradation" and how will this definition be applied in
identifying the proposed activities that will be subject to further
tier 2 review?
13) In assessing the degradation that will result from one or more
proposed activities, how will cumulative effects be addressed?
14) What are the minimum requirements applicable to the appli-
cant's evaluation of alternatives to allowing the lower water qual-
ity?
15) What criteria will the state use to determine whether reasonable
non-degrading or less-degrading alternatives are available?
16) What process/criteria will the state use to conclude that, in
allowing lower water quality, existing uses will be protected
fully?
17) How will proposed activities that provide "important social or
economic development" be identified?
18) How will it be determined, prior to allowing degradation, that
the highest statutory and regulatory requirements for all point
sources and all cost-effective and reasonable best management
practices for nonpoint sources have been achieved?
1 Region VIII states must, at a minimum, establish ad an hoc mechanism for
identification of high quality waters to allow for consideration of new water
quality data submitted by the project applicant and to address improvements
in water quality that may occur between triennial reviews. Supplementing
such an ad hoc mechanism with a "designationaJ" approach that is subject to
rulemaking requirements is optional.
-------
19) How will existing uses that have more stringent protection
requirements than currently designated uses be identified and
protected (as required by 40 CFR 131.12(a)(1))?
20) What process/criteria will the state use to conclude that existing
uses will be protected fully (e.g., will the state establish a rebut-
table presumption that protecting designated uses will also pro-
tect existing uses)?
21) What approaches or guidelines will be used to protect existing
uses from impacts that may not be direcdy addressed by the
applicable water quality criteria?
-------
CHAPTER 4:
DISCUSSION OF, AND RATIONALE FOR,
THE MODEL IMPLEMENTATION
PROCEDURE
The model antidegradation implementation procedure included
in Chapter 2 of this document provides an example of how states
can address each of the Region's "bottom-line" issues identified in
the previous chapter. The model procedure was developed assuming
that the applicable state antidegradation policy is identical to the fed-
eral policy (see 40 CFR 131.12 or Appendix 1). The Region notes
that the various components of the model procedure were patterned
after existing state antidegradation procedures that were reviewed in
preparing this guidance. Region VIII states are strongly encouraged
to base their antidegradation implementation procedures on the
model included in Chapter 2. However, it is not a requirement to
establish implementation procedures identical to the Region VIII
model. States may develop their own modified version of the
Region VIII model or a procedure entirely of their own design. The
only firm requirement is that antidegradation implementation proce-
dures comply with federal antidegradation requirements and address
the issues listed in Chapter 3 in a manner that is consistent with the
intent of the state and federal antidegradation policy. The approach-
es contained in the model procedure are recommended by EPA
Region VIII as a means of meeting that requirement.
This chapter of the guidance has two primary purposes. First, the
principal features of the Chapter 2 model procedure are highlighted.
Second, for a number of significant antidegradation issues (including
many of the priority issues itemized in Chapter 3), the approach
incorporated into the model procedure is outlined and the rationale
for that recommended approach is discussed. In some cases, alter-
native approaches, such as those reviewed in the Appendix 2 sum-
mary of state approaches, are also noted and discussed.
What are the principal features of the Region VIII model
implementation procedure?
The model implementation procedure included in Chapter 2 pro-
vides an EPA Region VHI-recommended example of how to handle a
number of difficult antidegradation implementation issues. For
example, the model procedure includes a level of antidegradation
protection (referred to as tier 2.5) not currently required or recog-
nized under the federal water quality standards regulation. Including
this extra level of protection in state antidegradation programs is not
-------
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GUIDANCE
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PRINCIPAL FEATURES OFTHEMODEL
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ANTIDEGRADATION PROCEDURE
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tiort in lde«d^trrg ONRW! candidate$ fs the overa]l
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HER 2.5 The tier 2.5 requirements are designed to maintain
existing water quality, but: are more flexible than tier 3
requirements. For example, permanent new or
expanded sources that could result in some degrada-
,, don of an GSRW segment may be allowed in certain
: cases,, provided that the proposed activity serves to
maintain or enhance the value, quality, or use of the
QSRWl An example would be wastewater treatment
plane effluent associated with a state park visitor cen-
ter. .
LTIER 2 The emphasis of the tier 2 procedure fe on identifica-
tion and implementation of any reasonable non-
degrading or less-degrading alternatives. This is
accomplished (in part) by applying tier 2 broadly and
by establishing a few threshold; by which proposed
activities are projected? to result: m "significant degra-
•• datkm.* Minimumf requin^ents?^ the completion
of ablatives analyses are presented!: The burden for
completing a preliminary evaluation fells on the pro-
ject applicant.; Thestate must then determine that the
applicant's evaluation is adequate* and whether any
reasonable less-degrading or non-degrading alterna-
:tivesare available;
TIER 1 iThe tier I procedure presumes that implementation of
the water quality criteria established, to protect desig-
natedi; uses will also result in protection of existing
of uses. Howevec a ptocess to protect: existing uses that
P-•• :< have: more stringent;: water quality; requirement: than
c^ntly designated; uses is. Included pursuant, to 40
-------
a requirement at this time. However, a number of states have, on
their own initiative, developed an extra tier of protection similar co
the one incorporated into Region VIII's model procedure. The extra
tier provides an additional way to ensure adequate protection of high
quality waters. Region VIII states are encouraged to incorporate a
tier 2.5 level of protection into their antidegradation programs.
What is Region VIITs rationale on the major issues?
Region VIII recognizes that, for many of the key antidegradation
implementation issues, there is a range of reasonable approaches that
are authorized under (or at least not precluded by) the federal water
quality standards regulation. This conclusion is . ^
supported by the review of existing state
approaches presented in Appendix 2 of this guid-
ance. However, to support consistent state imple-
mentation of antidegradation requirements, EPA
Region VIII believes it may be useful to the states
if, on each of the key issues, the Region recom-
mends an approach. It was to serve this basic pur-
pose that the model procedure included in ——
Chapter 2 was developed. In almost every case, the approaches
included in the EPA Region VIII model procedure are patterned after
those already in use by states. EPA Region VIII strongly recommends
that states and tribes base their antidegradation implementation pro-
cedures on the Chapter 2 model. Below, the rationale supporting the
Region's recommended approaches on major issues is presented.
; WSC«SSION«
-------
federal water quality standards regulation does not create, nor was it
intended to create; state regulatory authority over previously unregu-
lated activities. For this reason states may need to fashion their anti-
degradation policies and procedures to establish or clarify its authori-
ty to address certain activities that the state determines should be
subject to antidegradation review requirements (i.e., including those
that otherwise would be unregulated). The Region notes that some
states have established and successfully applied regulatory controls
in a number of areas where federal authority may be limited (e.g., a
number of states consider their water quality standards to be directly
enforceable). The Region also acknowledges and supports state anti-
degradation policies which are more stringent than the federal anti-
degradation policy.
The model implementation procedure uses the term regulated activi-
ties to identify the types of projects that would be subject to anti-
degradation review requirements. (See definition in Chapter 2.) The
Region notes that, as described in Chapter 3, antidegradation review
requirements must be applied, at a minimum, to such regulated
activities. In general, the model procedure would not result in regu-
lation of any activities that are not already regulated under existing
surface water quality control programs. The Region believes this
approach makes sense given the current status of antidegradation
implementation in Region VIII and the widespread resource con-
straints faced by the state and tribal agencies charged with imple-
menting surface water quality control programs.
The Region notes that antidegradation principles can and should
affect a number of activities even where application of the antidegra-
dation review requirements is not mandated. As a general planning
tool, it always makes sense to consider existing ambient water quali-
ty and evaluate available means to protect that water quality. Thus,
although a state may not have authority to require a formal anti-
degradation review or deny a particular category of activity based on
its antidegradation requirements, there may still be value in applying
the antidegradation principles in an analysis of potential environ-
mental impacts.
Another related point that states need to communicate to project
applicants is that, in developing project plans, antidegradation
requirements should be addressed early in the process. This considera-
tion is particularly important for multi-stage projects where permit-
ting requirements may not be addressed until the later stages. In
particular, applicants need to be made aware of the need to identify
the tier of antidegradation that would apply and to consider the
state's requirements under that tier. In general, applicants need to
be made aware that, under antidegradation, the baseline against
which impacts will be measured is often not the numeric criterion
-------
applicable to the waterbody segment, but rather the existing ambi-
ent quality of the segment. Under tier 2 of antidegradation, for
example; activities that would result in "significant degradation" to
existing water quality would be subject to tier 2 requirements.
Consider also that a variety of projects that affect water quality (e.g.,
NEPA actions requiring an EIS and. ultimately, a permit/water quality
certification) are planned and developed over a period of years.1
Typically, the permit application is not made until near the end of
such long-term projects. If antidegradation requirements and the
likelihood of impacts to existing water quality are not considered
until the permit application is made, the applicant may bee a bur-
densome exercise to demonstrate that the antidegradation policy is
satisfied. If, however, the antidegradation requirements had been
considered from the beginning, the applicant will avoid having to
revisit previously completed water quality and alternatives analyses.
In summary, the Region is requiring that, at a minimum, states apply
antidegradation requirements to all activities that are already regulat-
ed under surface water quality control programs. However, the basic
philosophy of the antidegradation policy is that all activities that may
affect water quality should be carefully reviewed to determine if alter-
natives to allowing the degradation exist. Accordingly, states should
consider expanding their application of antidegradation require-
ments to address some of the activities that, although not yet regu-
lated, nevertheless have a profound influence on surface water quali-
ty. States should also make an effort to promote consideration of
antidegradation requirements as early in the process as is possible
(especially where multi-stage projects are initiated that may not be
"regulated" until the later stages).
Antidegradation and TMDL Development
In general, antidegradation procedures establish a process for
reviewing individual proposed activities to determine if the activity
can be authorized under state and federal antidegradation require-
ments. However, under CWA § 303(d), states and EPA are often
responsible for developing control strategies for multiple as well as
individual sources in watersheds where water quality standards are
not being achieved (i.e.. Total Maximum Daily Loads (TMDLs)).
TMDLs are a primary tool used in translating water quality standards
into meaningful controls. TMDLs apply to all pollutant sources with-
in a watershed (i.e., both point and nonpoint source). In addition,
TMDLs apply to all pollutants, including toxics, conventional pollu-
tants, and sediment. Section 303(d) requires that TMDLs be devel-
1 Antidegradation should also be considered "up-front" during the long-term
planning associated with municipal wastewater treatment facilities.
-------
oped to implement water quality standards — including all numeric,
.narrative, and antidegradation components.
In the course of developing TMDLs, questions may arise regarding
the applicability of antidegradation requirements. For example, con-
sider the case where a project applicant has agreed to implement
more stringent controls ac an upstream site to compensate for a new
or expanded discharge downstream. Such an arrangement will be
referred to in this document as upstream/downstream "trading."1
Where trading occurs, the question becomes whether to apply anti-
degradation requirements (i.e., under tier 1, 2, or 3) based on the
overall impact of the TMDL on water quality or, alternatively, on each
individual source included in the TMDL The latter approach would
mandate application of antidegradation wherever a significant new
downstream source of a pollutant would be established (i.e., regard-
less of the overall effect of the trade on water quality). Under the
former approach, antidegradation would not necessarily be applied
because, overall, existing water quality would be maintained or
improved at all points, at all times, and for ail parameters.
The model procedure addresses this issue as follows. Under tier 3,
trading may be allowed, but only in segments upstream of the
ONRW where the applicant can show that water quality will be
either maintained or improved at all points, at. all times, and for all
parameters. Under tier 2.5, trading may also include new sources of
pollutants directly into an OSRW segment, provided that sufficient
counterbalancing upstream controls are established to maintain (and
improve, it is hoped) the quality of the OSRW segment. Under tier 2,
the overall impact of the trade may be considered in judging
whether significant degradation will occur. Following this procedure,
proposed new or expanded downstream sources may not be judged
as significant degradation as long as an appropriate level of counter-
balancing upstream controls will be implemented. However, such
determinations of significant degradation will be addressed on a
case-by-case basis. Under tier l, trading may be allowed provided
that existing uses are fully maintained and protected.
The Region believes that this approach to trading is defensible and
sound for a number of reasons. One factor supporting this approach
is that "ie proper focus of antidegradation programs shou'd be on
proposed activities that will have an effect on existing water quality.
1 Trading is defined as establishing upstream controls to compensate for new
or increased downstream sources, resulting in maintained or improved water
quality at all points, at ail times, and for all parameters. Trading may involve
point sources, nonpoint sources, or a combination of point and nonpoint
sources. It is presumed that ail TMDLs involving trading include an appropri-
ate margin of safety to account for uncertainties in the analysis.
-------
"Trading," as defined in this document, can only result in maintain-
ing or improving water quality. Thus, where trading is implemented
in a tier 2 waterbody, the state has the option to conclude that,
based on the overall effect on the watershed, significant degradation
would not occur (i.e., even where one or more new downstream
sources of pollutants would be established). Another factor support-
ing this approach is that, by applying antidegradation requirements
on a broader scale, the regulatory authority can support and stimu-
late nonpoint source controls that might not otherwise be imple-
mented. EPA Region VIII believes that because nonpoint source pol-
lutant reduction may be more cost-effective than point source pollu-
tant reduction, upstream/downstream trading is a viable and sound
approach to establishing watershed-based control approaches and
improving water quality.
RATIONALE
Proposed Activities Upstream of QNRW Segments
An especially difficult issue related to tier 3 implementation is
establishing requirements applicable to new or expanded sources of
pollutants that are proposed upstream of an ONRW segment. The
model procedure proposes to allow such new or expanded sources
where they would have no effect on the quality of the downstream
ONRW segment. Implementing this requirement may involve the use
of water quality models to determine whether dilution, fate, and
transport processes achieve sufficient in-stream reduction of treated
wastewater discharges to maintain the quality of the downstream
ONRW segment: Available data and best professional judgment must
be employed in implementing ONRW requirements in such cases.
The rationale for this approach is that the primary
alternative, prohibiting all new or expanded
upstream discharges that would result in any
increased loading of pollutants, may be too restric-
tive in many cases. In essence, the Region does
not believe that an ONRW designation at the mid-
dle or bottom of a watershed should prohibit ail
upstream new or increased sources, regardless of
water quality effects on the ONRW segment. In
addressing upstream sources, the Region believes it
is reasonable and appropriate to first determine
whether ONRW quality will be compromised. A
second argument supporting the recommended
approach is that establishing an effective prohibi-
tion of all new or expanded upstream sources,
regardless of effects on water quality, would create
a strong disincentive for designating ONRW seg- —— ——-
ments and providing any antidegradation protection beyond tier 2
requirements. On the other hand, the Region does not believe that
prohibiting "measurable" changes in water quality (e.g„ as defined by
the error associated with the analytical technique utilized) is adequate-
In essence, the Region does
not believe that an ONRW
designation at the middle or
bottom of a watershed
should prohibit aU upstream
new or increased sources,
regardless of water quality
effects on the ONRW seg»
merit. In addressing
upstream sources, the
Region beUeves it is reason*
able and appropriate to first
determine whether ONRW
quality wilt be compromised.
-------
ANTtOEGftADATtOH
ly protective because such an approach may allow acute and/or
m (hi chronic conditions in a waterbody before "measurable" degradation
is detected chemically.
Antidegradation and Interstate Water Pollution
A key issue related to implementation of antidegradation is the
extent to which the antidegradation requirements of a downstream
state apply to proposed activities in upstream states. A recent
Supreme Court case (Arkansas v. Oklahoma, February 26, 1992)
addressed this very issue. The case concerned EPA's issuance of an
NPOES permit for a new discharge located in Fayetteville, Arkansas,
39 miles upstream from the Oklahoma state line. The proposed
Fayetteville discharge was to flow through a series of three creeks
over 17 miles, and then enter the Illinois River at a point 22 miles
upstream from the Arkansas-Oklahoma border. Oklahoma contested
the EPA permit on the grounds that it violated the state's prohibition
of new or increased point source discharges to the upper Illinois
River.
EPA Region VIII believes that states and tribes should be aware of the
results of the Arkansas v. Oklahoma case, as this opinion will influ-
ence EPA's approach to such interstate cases. In the opinion, which
emphasized EPA's discretion. Justice Stevens heid that the Clean
Water Act clearly authorizes EPA to require that poinc sources in
upstream states not violate water quality standards in downstream
states, and that EPA's interpretation of those standards governed.
The court upheld as reasonable EPA's interpretation of the Oklahoma
standard as prohibiting new sources directly to the Illinois River in
Oklahoma and out-of-state sources which had an effect on the Illinois
River in Oklahoma. The Region encourages all interested parties to
become familiar with the Arkansas v. Oklahoma decision, copies of
which are available from the EPA Region VIII office. Water
Management Division.
Likewise, EPA Region VIII encourages all states and tribes to be
aware of the water quality standards applicable to border waters and
to involve neighboring states and tribes in its triennial review
process for such waters. Cooperative efforts between states and
tribes can reduce the potential for conflicts, and also reduce the need
for EPA to arbitrate such conflict? oursuant to the Agency's authority.
Defining Temporary and Limited Impacts to QNRWs
Another major issue pertaining to tier 3 implementation is iden-
tifying the types of "temporary and limited"1 impacts that should be
1 In discussing ONRW requirements, the 1983 water quality standards regula-
tion indicates: "States may allow some limited activities which result in tempo-
rary and short-term changes in water quality."
-------
(p'WSCIISSidN^©-
allowed in ONRW segments. The approach reflected In the model ,
implementation procedure is to make such determinations based on
a case-by-case evaluation of relevant fiactors. As a non-binding rule
of thumb, activities would be allowed that would result in less than a
5% change in ambient water quality fbr a period lasting less than
one month. However, greater changes in water quality with longer
durations could be allowed in specific cases (e.g.. where the activity
would result in long-term water quality benefit).
The rationale fbr this approach is that it is impossible to establish a
meaningful numerical definition of a "temporary and limited"
impact. Such determinations must be made based on site-specific
circumstances in order to allow for all possibilities. The Region
believes that in some cases, a 15% change in water quality may rea-
sonably be considered a limited impact, while in others a 5%
change would not be. Similarly, an impact lasting up to a year or
more may in some cases be appropriately considered temporary
(e.g., where the long-term best water quality interests of the ONRW
segment are served). In general, protecting ONRW waters requires
that any allowable impacts be as minimal as possible. The Region
notes that a Senate report associated with the 1972 CWA amend-
ments, in discussing maintenance of ecological integrity, stated that
"...maintenance of such integrity requires that changes in the envi-
ronment resulting in a physical, chemical, or biological change in a
pristine waterbody be of a temporary nature, such that by natural
processes, within a few hours, days, or weeks, the aquatic ecosystem
will return to a state functionally identical to the original."
Tier 2.5 gives a state or
tribe the ability to provide
On' additional level of protect
turn to high quality waters.
encouraged by EPA Region VIII, however, as an additional means to
protect existing high levels of water quality on segments which
would not otherwise be designated as ONRW designation. The
advantage of tier 2.5, as it is presented by the model implementa-
tion procedure, is that it gives a state the ability to provide an addi-
tional level of protection to high quality waters. Although the specific
implementation requirements associated with tier 2.5 may be cus-
tomized to reflect the needs of individual states, the Region believes
that the tier 2.5 requirements contained in the model procedure
establish a useful additional level of protection for high quality
waters. States may wish to incorporate a tier 2.5 into their anti-
degradation programs to provide a supplementary tool with which
important state water resources (i.e.. which do not qualify for ONRW
protection) may be protected.
Tier 2.5
The basic issue pertaining to tier 2.5 is
whether this level of protection is needed to fully
protect the quality of surface waters. Region VIII
notes that this level of protection is not required
under the federal water quality standards regula-
tion. Incorporating this level of protection is
-------
ip&I
;wnosG*As**noM
Region VIII also notes that the basic concept of tier 2.5 originated
ffom state antldegradation programs. A number of states have suc-
cessfully demonstrated the value of applying this extra level of protec-
tion to segments which would not qualify for tier 3 ONRW protection.
Identifying High Quality (Tier 2) Waters
A fundamental issue that must be a primary focus of tier 2
implementation guidance is identifying the waters and/or parame-
ters that are high quality and subject to tier 2 requirements. As dis-
cussed in Appendix 2 of this guidance; a variety of state approaches
are in use or under development. These approaches basically fall
into two categories: (1) waterbody-by-waterbody approaches, and
(2) parameter-by-parameter approaches. The approach incorporated
into the model implementation procedure is a modified waterbody-
by-waterbody approach. The overall quality and value of a segment
is judged, based on appropriate factors, to determine whether it is of
sufficient high quality to warrant tier 2 protection. The decision can
be made either through a rulemaking action (i.e., by the Board or
Commission) or during the antidegradation review of a proposed
activity. However, the presumption established by the model proce-
dure is that state waters are high quality"
The rationale for this approach is founded in Region VIII's belief that:
(1) wherever water quality is better than water quality standards,
that assimilative capacity is worthy of protection, and (2) most
waterbodies have assimilative capacity for a large number of water
quality parameters. Consequently, tier 2 protection should be afford-
ed to most waters. An exception to this presumption would be
waters where fishable/swimmable uses are clearly not attained.
Another exception would be waters where existing quality is not
"better than necessary" to support fishable/swimmable uses (i.e.,
assimilative capacity does not exist for the parameters that would be
affected by the proposed activity). Such waters are likely to have
assimilative capacity for some parameters but, overall, such seg-
ments are not high quality and should not be subject to tier 2
requirements. The Region believes that the original intent of anti-
degradation tier 2 was to maintain and protect the existing quality of
high quality fishable/swimmable waters. The Region recognizes that
there is considerable merit in applying tier 2 wherever assimilative
capacity exists (i.e., for a parameter that is to ^e affected by the pro-
posed activity). However, following such a "parameter-by-parame-
ter" approach could result in application of tier 2 to waters which are
not attaining and cannot attain fishable/swimmable goal uses. Thus,
the Region believes that the parameter-by-parameter approach does
not always focus implementation efforts on truly high quality waters.
-------
Significant Degradation
Another major issue that must be addressed under tier 2 imple-
mentation guidance is identifying activities that will result in signifi-
cant degradation. As discussed in Appendix 2 of this guidance, this is
probably the single issue that has resulted in the widest diversity of
state approaches. State "significance" tests range from simple to
complex, involve qualitative or quantitative measures or both, and
often vary depending upon the type of parameter or the accuracy of
the analytical method used to measure the parameter. The model
implementation procedure establishes a fairly low (qualitative) thresh-
old of "significance." The procedure specifies a number of factors
that may be the basis for determining the significance (or insignifi-
cance) of the proposed degradation on a parameter-by-parameter
basis. The approach relies primarily on best pro-
fessional judgment, allows for a determination to
be made in relatively "data-rich" and "data-poor"
situations, and establishes state authority to
impose data-collection requirements on the pro-
ject applicant. Following the model procedure,
most regulated activities that would result in
increased loadings would be considered to pose : _
significant degradation.
The rationale for this approach is that only proposed activities that
will result in truly minor impacts to existing water quality should be
exempted from the tier 2 review requirements. EPA Region VIII
believes that tests of significance represent a valuable means of
focussing state resources appropriately; however, such tests should
not unduly reduce the state's ability to pursue the primary function
of tier 2. which is to ensure that non-degrading or less-degrading
alternatives are identified and implemented. Establishing a high
threshold of significance would run counter to this objective (i.e.,
because proposed activities which are judged as "insignificant" are
not subject to alternatives analysis requirements). Likewise, estab-
lishing a rigid quantitative measure of significance can also pose an
unnecessary obstacle to evaluation of alternatives because of the
technical and resource constraints associated with predicting the in-
stream effects of a proposed activity. It is for this reason that the
model procedure allows for determinations of significance based on
simple analyses such as dilution factors and proposed effluent load-
ings. It is also for this reason that the significance test may be by-
passed entirely where the Division believes that reasonable alterna-
tives to lowering water quality are clearly available. In order to
ensure that any non-degrading or less-degrading alternatives are
identified and implemented, the Region believes that tests of signifi-
cance should screen out only those activities that would result in
truly insignificant water quality effects. The model procedure
includes a low threshold of "significance" so that an evaluation of
alternatives will be completed for most proposed activities.
discussion and
pgftnOHAtr-:
Tests ofsignificance should
screen out only those activu
ties that would result in
truly insignificant water
quality effects.
55
-------
ANTtDEGRADATtOK
" " ' '
Cumulative Effects
Determining the significance of a proposed activity can be com-
plicated where multiple new or expanded sources in a basin are pro-
posed over a relatively short period of time. Where such new or
expanded proposed sources are evaluated separately with respect to
antidegradation requirements, it may be possible to reasonably con-
clude that each individual source would not pose significant degrada-
tion. However, taken cumulatively, the degradation resulting from all
sources in such cases can be quite significant. Likewise, multiple
periodic increases in loadings torn a single source can be relatively
minor individually but very significant in a cumulative sense.
The model antidegradation procedure addresses this issue by identi-
fying cumulative effects as one of the factors to be considered in
evaluating significant degradation. The procedure allows the state to
base determinations of significance on the cumulative effects of mul-
tiple sources or the cumulative effects of multiple periodic increases
from a single source. In either case, further antidegradation review,
including evaluation of alternatives, can be required even for individ-
ual proposed actions which normally would not be considered signif-
icant. Although the Region believes that the emphasis of developing
state and tribal programs should, at least initially, be on evaluating
proposed sources individually. EPA certainly recommends that states
and tribes be alert for cumulative effects and factor such considera-
tions into their antidegradation review process where appropriate.
Permitted versus Existing Effluent Qualify
A sub-issue within the overall "significance" question is how
states should address reissuance of NPDES permits where existing
facility performance is better than the NPDES permit requires. In
such cases, reissuing the same permit can be viewed as authorizing
degradation (i.e. because the permit would be authorizing the per-
mittee to increase existing loadings to permitted levels). Through
the use of a case example, the model procedure explicitly states that
reissuing the same permit limits can be treated as significant degra-
dation in certain cases.
The rationale for this approach is that there may be situations in
which reissuing the same permit limits should be subjected to fur-
ther review, including the evaluation of alternat ,'es. Fbr persistent
toxics where there are existing downstream accumulation problems
in either fish tissue or sediments, there may be a need to base the
permit limits of upstream sources on their existing effluent quality.
Such "EEQ" based limits ensure that the downstream accumulation
problems will not become worse as a result of increased upstream
loadings. Reissuing the same permit should also be subject to fur-
ther review where there may be pollution prevention alternatives
that would result in complete elimination of the parameter(s) of con-
56
-------
cern from the effluent. In either of these situations (and perhaps
others), it may be appropriate to consider reissuing the same permit
limits as significant degradation.
Data Requirements
A critical issue is the question of the variety, quantity, and quali-
ty of data necessary to implement antidegradation tier 2. particularly
with respect to identifying which waters are "high quality," and
determining the water quality "significance" of proposed activities.
Certainly, monitoring and assessing surface water quality is a diffi-
cult and ongoing task, and projecting the water quality that will
result from proposed activities can be made difficult by the inherent
complexity of receiving water systems. The critical issue becomes:
How much information and analysis is needed to make the required
antidegradation tier 2 findings, and where information is lacking,
who should be responsible for providing it? An additional overriding
concern is, where information may be lacking, what approach will
ensure that water quality is protected and that the fundamental pur-
pose of tier 2 is served?
EPA Region VIII believes that implementation of antidegradation tier
2 requirements need not pose an undue burden on the state and
tribal agencies charged with administering surface water quality pro-
grams. The model antidegradation procedure included in this guid-
ance has been developed to allow states and tribes to focus
resources on significant problems and issues and, where necessary,
place the information-gathering burden on the project applicant.
With respect to antidegradation tier 2. the Region believes and advo-
cates that, rather than getting unduly "bogged down" with assessing
and projecting water quality conditions, state/trib-
ai programs should focus on evaluation of non-
degrading and less-degrading alternatives in order
to minimize the pollutant loadings that will result
from the proposed activity. By focussing on the
projected pollutant loadings and costs associated
with each available alternative, such alternatives
analyses can occur independent of the analysis of
receiving water quality conditions. The Region
believes that evaluation of alternatives is the prop-
er focus of tier 2 reviews, and has developed the
model procedure to achieve this focus. To this
end, the model procedure:
(1) includes an initial presumption that all surface waters are high
quality and subject to tier 2 review requirements;
DISOISSIONAND
yzzrffy&y.-//. - - '
EP&Region vm believes
that implementation ofanti-
degradation tier 2 require*
ments need not pose an
undue burden on the state
and tribal agencies charged
with administering surface
wati r quality programs.
(2) allows for basing high quality determinations on ancillary data
such as land use information, presence of sources, biological
health, etc.;
-------
-"//..'.V-ft WAV#
tBEGJOttVli
mmtmtmem
fifteen
(3) establishes a low threshold or definition of "significant degrada-
tion;"
(4) allows for determinations of significance based on simple analy-
ses and factors which do not require modeling (such as percent
change in source loadings);
(5) provides for by-passing the significance test entirely where rea-
sonable alternatives to lowering existing water quality are clear-
ly available; and
(6) allows for the data-gathering burden to be placed on the project
applicant with respect to any data that may be needed to make
the high quality and significance findings.
Although monitoring and data analyses are critically important to the
total maximum daily load (TMDL), wasteload allocation, and NPDES
permitting processes. EPA Region VIII believes that implementation
of antidegradation tier 2 need not focus on such issues. In fact, the
Region believes that undue attention to the high quality and signifi-
cance questions can be an obstacle to the primary function of a tier
2 program, which is to ensure that the least-degrading reasonable
alternative is being implemented.
Determinations of Importance and Necessity
The federal water quality standards regulation requires that the
water quality of high quality waters not be lowered unless it is deter-
mined that such degradation is necessary to accommodate important
economic and social development.1
Implementing this requirement requires applica-
g tion of a two-pan test. The state must find that
H the proposed activity is important, and the state
| must find that any associated water quality degra-
Ci dation is necessary (i.e., cannot be avoided by
>:f: selecting an available alternative). Clearly, there
will be many instances where important activities
can proceed without degrading water quality.
However, it would be inappropriate to assume,
once finding that an activity is important, that the
_ associated watt/ quality degradation is necessary.
Given the variety of available engineering approaches and the
emerging importance of pollution prevention. EPA Region VIII
believes that the finding of necessity is among the most important
1 Note that the findings of necessity and importance are requirements only
under tier 2: these findings are not required under the other tiers of an anti-
degradation program.
-------
aspects of a state antidegradation program. The model procedure
addresses evaluation of alternatives by requiring that the applicant
prepare an analysis that provides substantive information pertaining
to the costs and environmental impacts associated
with available alternatives.
CHAPTER*
discussion and
II'KftrtOliAtE-
•¦S* A 1
In evaluating the applicant's analysis, the state
must ensure that all feasible alternatives to allow*
ing the degradation have been adequately evaluat-
ed by the project applicant. The state may
request additional information from the applicant
to supplement the initial evaluation. The proce-
dure references the EPA Headquarters guidance
regarding the use of economics in the water quali-
ty standards program. The state's preliminary
finding regarding the necessity of the proposed
degradation is subjected to public review along
with all its other antidegradation review findings.
A non-binding rule of thumb is included that spec-
ifies that "...non-degrading or less-degrading pol-
lution control alternatives with costs that are less
than 110% of the costs of the pollution control
measures associated with the proposed activity
shall be considered reasonable."
If the Division determines that reasonable alterna-
tives to allowing the degradation do not exist, the
Division shall continue with the tier 2 review and
document the substance and basis for that prelimi-
nary determination using the antidegradation review
worksheet (see page 35).
POIEPmAZ NON-DEGRAD~
INGOR LESS-DEGRADING
-k;. .'V- -•
> pollution prevention/
source reduction measures
r;- '(eifrr substitution of less
The Region strongly encourages states and tribes
to stress the evaluation of alternatives in imple-
menting antidegradation tier 2 requirements. Use
of tier 2 to identify and require reasonable and less-degrading (or
non-degrading) alternatives can be an effective tool with which to
maintain and protect existing water quality. The Region believes that
the recommended alternatives analysis procedure provides a work-
able mechanism with which existing water quality can be protected
and strongly advocates that states and tribes emphasize this aspect of
the antidegradation program.
Identifying Existing Uses 1
A major issue related to tier 1 implementation1 is whether to
presume that uses which have been designated for a segment appro-
> innovative treatment tech~
ndtogy(e.g.f land applicac-
tion of wastewater)
> advanced treatment
technology
» water recycle or reuse
> process changes
> reduction in scale of the
project
>¦ seasonal or controlled dis-
charge options to avoid
critical water quality
periods
> improved operation and
- maintenance of existing
treatment systems
»~ alternative discharge
locations
1 Note that tier 1 requirements apply to ail surface waters.
-------
priately address all existing uses. For example, where a class 2
(habitat-limited) aquatic life use has been designated for a segment,
is it appropriate to presume that the existing use is not, in actuality, a
class 1 aquatic life use? At first glance, this may seem a reasonable
approach because designated uses are required, at a minimum, to be
inclusive of attainable uses, and in most cases, existing uses are cer-
tainly attainable! However; in some cases water quality may have
improved since the designated use was assigned. In other cases, Lhe
designated use may have been set based on inadequate information.
The approach incorporated into the model implementation proce-
dure is to presume that existing uses are appropriately addressed by
designated uses, while also establishing state authority to protect
existing uses where this presumption is overcome based on. for
example, data that become available from the project applicant or
through the public participation and intergovernmental coordination
processes.
The basis for this approach is that, although it does not make sense
from a management perspective to revisit all previous use designa-
tion decisions as part of the antidegradation program, occasionally it
may be determined that currently designated uses do not adequately
reflect the existing uses of the segment. Where this is determined to
be the case, protection of existing uses may require a more stringent
level of protection than would normally be associated with the cur-
rently designated use. In such cases, federal antidegradation require-
ments mandate that the more stringent requirements be applied.
Identifying Existing Uses 2
Another tier 1 question is whether to evaluate existing uses fol-
lowing a different or more fully developed hierarchy of uses than is
applied in designating uses. For example, should a distinction be
made between an existing coldwater salmonid fishery versus a cold-
water fishery that does not support salmonids? Should proposed
activities that would result in fundamental shifts in the aquatic com-
munity. without eliminating a designated use, be considered to elimi-
nate an existing use? The model procedure addresses this issue by
using the same hierarchy (i.e., degree of precision) for both designat-
ed and existing uses. Following this approach, the protection afford-
ed to existing uses is limited by the degree of refinement associated
with the state designated uses. Sts*^ that have more specific desig-
nated uses (i.e., including a number of use sub-categories) would
thus be able to address more subtle effects on existing uses. States
with a less specific designated uses would have less precision associ-
ated with their existing use protection scheme.
The rationale for this approach is that a separate use classification
system should not be developed for purposes of existing use protec-
tion. It is simpler and easier to implement existing use protection by
-------
revisiting the original designated use question, determining whether
an existing use is or has been attained since 1975 that has more
stringent requirements than the currently designated uses, and
implementing controls to protect that existing use as if it were a des-
ignated use. To ensure effective protection of
existing uses, EPA Region VIII supports further
development of state aquatic life designations to
provide an appropriate number of sub-categories.
Continued use of biological surveys and biological
assessment programs will also promote more
effective existing use protection.
¦ - .
. ......
|*MSOISSION4*«Oh
llllliEgai
tiono
Em
Impacts Not Addressed by the Applicable Water
Quality Criteria
A final issue concerns whether antidegrada-
tion authorizes states to prohibit impacts to exist-
ing uses that may not be adequately or specifically
addressed by the water quality criteria which have
been established to protect designated uses (e.g.,
impacts to aquatic life habitat that may result
from regulated discharges of clean sediment).
The model implementation procedure establishes state authority to
address such impacts, but also establishes a presumption that imple-
mentation of the applicable water quality criteria will fully protect
designated and existing uses.
Due to resource limitations, EPA believes that it makes sense to place
priority on implementation of the applicable water quality criteria,
and it is for this reason that the model procedure presumes that
implementation of such criteria will fully protect designated and
existing uses. However, pursuant to state and federal tier 1 require-
ments. states must protect existing uses against impacts, even where
it is not possible to tie such impacts to violations of applicable water
quality criteria. For example, where it can be demonstrated that
aquatic life habitat would be altered by a (regulated) discharge of
clean sediment such that an aquatic life existing use would be
impaired, state and federal existing use protection requirements
authorize a state to deny such discharges, even where it may not be
possible to tie the impact directly to a water qua'ty criterion.
\ "¦
ixttUK:.
gories* Continued use of bio*
assessment programs wUt
also promote more effective
existing use protection.
&
-------
§iii
APPENDICES
APPENDIX 1: BACKGROUND INFORMATION
What is the history of antidegradation?
Antidegradadon predates the creation of EPA in 1972. The basic
policy was established on February 8, 1968, by the Secretary of the
U.S. Department of the Interior. The federal policy was included in
EPA's first water quality standards regulation (see 40 FR 55340).
The existing federal requirements pertaining to antidegradation were
established as part of the amendments to the water quality stan-
dards regulation that were promulgated November 8. 1983 (see 40
CFR 131.12). The Water Quality Act of 1987 recognized antidegra-
dation as an integral component of surface water quality control pro-
grams (see CWA § 303(d)(4)(B)).
What are the federal requirements pertaining to
antidegradation?
The federal requirements pertaining to antidegradation are included
in § 131.12 of the federal water quality standards regulation. In
essence, these requirements direct states to adopt an antidegrada-
tion policy and identify the procedures that will be followed in
implementing the policy. Certain minimum requirements are estab-
lished for such policies and implementation procedures. Section
131.12 of the federal water quality standards regulation reads as fol-
lows:
§ 131.12 Antidegradation policy.
(a) The state shall develop and adopt a statewide
antidegradation policy and identify the methods for
implementing such policy pursuant to this subpart.
The antidegradation policy and implementation meth-
ods shall, at a minimum, be consistent with the fol-
lowing:
(1) Existing in-;Stream water uses and the level of
water quality necessary to protect the existing uses
shall be maintained and protected.
(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, that
quality shall be maintained and protected unless the
-------
state finds, after full satisfaction of the Intergovern-
mental coordination and public participation provi-
sions of the state's continuing planning process, that
allowing lower water quality is necessary to accom-
modate important economic or social development in
the area in which the waters are located. In allowing
such degradation or lower water quality, the state
shall assure water quality adequate to protect existing
uses fully. 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 manage-
ment practices for nonpoint source control.
(3) Where high quality waters constitute an out-
standing National resource, such as waters of national
and state parks and wildlife refuges and waters of
exceptional recreational or ecological significance,
that water quality shall be maintained and protected.
(4) In those cases where potential water quality
impairment associated with a thermal discharge is
involved, the antidegradation policy and implement-
ing methods shall be consistent with section 316 of
the Act.
What guidance has EPA developed to support compliance with
the antidegradation requirements?
Antidegradation guidance has been issued by EPA at both the
national and regional levels. At the national level, guidance on anti-
degradation is contained primarily in: (1) the preamble to the
amendments to the water quality standards regulation that were
published November 8. 1983 (see 48 FR 51400), (2) the Water
Quality Standards Handbook which was issued soon after the 1983
amendments were published, and (3) Questions & Answers on:
Antidegradation. which was issued in August of 1985. Additional
guidance on how antidegradation can be incorporated into the CWA
§ 401 certification and CWA § 404 permits programs is included in
Wetlands and 401 Certification. Opportunities and Guidelines for States
and Eligible Indian tribes.
A number of EPA Regional Offices, most notably Regions I, IV, V,
and IX, have also issued antidegradation guidance. Because the
water quality standards approval authority under CWA § 303(c) has
been delegated to the Regional Offices, such Regional guidance is
generally developed to supplement the national guidance and pro-
-------
^Bill
yy«tDE6itKlUtl|^
6UIDANCI E3W8 vide additional recommendations regarding particular antidegrada-
r-vfrv tion approaches that would be approved by the Regional
Administrator. Recently, antidegradation implementation guidance
and procedures have also been developed as one component of the
Great Lakes Water Quality Initiative. EPA participated in the develop-
ment of that antidegradation approach, which is to be applied to the
Great Lakes and its tributaries.
What is the overall status of state antidegradation
implementation efforts?
All fifty-seven states and territories subject to water quality stan-
dards program requirements have established antidegradation poli-
cies as part of their water quality standards. Many of these antidegra-
dation policies are identical to the federal policy presented above.
Others have been customized to the particular needs of the state.
EPA allows such customization as long as the state policy is consistent
with (or more stringent than) the intent of the federal policy.
Implementation of antidegradation requirements is different, to
varying degrees, in every state and territory that is actively imple-
menting antidegradation requirements. Some states incorporate
implementation details into the section of their water quality stan-
dards that addresses antidegradation. Other states include only an
antidegradation policy in their standards and document their imple-
mentation procedures in a separate document. Both of these
approaches have been approved by EPA.
State implementation also varies in the specific approaches
employed to address a number of key antidegradation issues.
Because the water quality standards regulation does not identify spe-
cific implementation approaches that must be utilized by states, a
fairly diverse array of methods have been approved by the EPA
Regional Offices. Fbr example, a wide range state approaches have
been developed and applied to address protection of high quality
waters, also known as antidegradation tier 2. Tier 2 issues that have
attracted varying state approaches include the process for identifying
waters subject to tier 2 protection and the process for identifying
proposed activities that should be subjected to the tier 2 review
requirements (i.e., act./ities that will result in "degradation or lower
water quality" as this phrase is used in Section 131.12(a)(2) of the
federal policy). Examples of state antidegradation implementation
methods on these and other issues are discussed in greater detail in
Appendix 2 of this guidance.
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APPENDIX 2: STATE APPROACHES TO
IMPLEMENTING ANTIDEGRADATION
The objective of this appendix is to present the results of a
review of state antidegradation implementation approaches conduct-
ed in April of 1992 by EPA Region VIII. The principal objective of the
review was to characterize the range of approaches in use on a num-
ber of key antidegradation implementation issues.
The implementation procedures for a total of twenty states were
reviewed. At the time of the review, these procedures were in vari-
ous stages of development. The state procedures and their status at
the time of this review are shown in l&ble 1. It was decided to
include in the review draft procedures and procedures not yet
approved by EPA. The primary basis for this decision was that the
objective of the review was simply to compile ideas for addressing
each issue. It was also Region VIIl's judgment that draft state proce-
dures may be more or less technically valid, and more or less envi-
ronmentally protective, as final state procedures. Finally, draft state
procedures represent a considerable percentage of the existing state
antidegradation methodologies.
In characterizing the range of approaches used by the states, an
effort was made to use consistent terminology across states for key
terms or phrases (e.g., significant change in water quality). The
issues which were included in the review span all three tiers of anti-
degradation. In order to establish how the issues relate to one
another and to an overall antidegradation program, each issue has
been referenced to Figure 1, which is intended to represent the
flow of a typical state antidegradation procedure. Note that Figure
1 is basically a composite flow chart, and that all state antidegrada-
tion programs do not conform exactly to the procedure which is
illustrated.
Please also note that, because the purpose of the review was simply
to characterize the range of approaches in use, the description of a
state's approach may be somewhat simplified or paraphrased in the
discussion presented below. Refer to the actual procedures for a
more detailed description of the str.'.e's overall procedure.
-------
AMTlOEGllADATtOtt,
guidance
'¦'w^w^riig
TABLE 1
STATE ANTIDEGRADATION IMPLEMENTATION
PROCEDURES REVIEWED
Index EPA
No. * Region State Status
1
I
Connecticut
Final
2
Massachusetts
Draft
3
Maine
Draft
4
New Hampshire
Draft
5
Rhode Island
Draft
6
Vermont
Draft
7
II
New Jersey
Final
8
New York
Draft
9
III
Delaware
Draft
10
Pennsylvania
Draft
11
Virginia
Draft
12
IV
Florida
Final
13
North Carolina
Final
14
V
Wisconsin
Final
15
VI
Texas
Final
16
VIII
Colorado
Final
17
Montana
Final
18
IX
Arizona
Final
19
California
Draft
20
X
Idaho
Final
" Where an example from a state procedure is included in the dis-
cussion presented in this section (Appendix 2). the source of the
example is identified using these index numbers.
-------
FIGURE 2
FLOW OF A TYPICAL STATE ANTIDEGRADATION PROCEDURE
TIER 3
no
Is the receiving water or a down-
stream segment an ONRW?
fyes
<
Will the proposed activity affect
ONRW water quality?
no
yes
Apply ONRW
requirements.
no
TIER 2
TIER 1
Does the receiving water qualify for
tier 2 protection?
Tyes
Will the proposed activity lower
water quality?
Tyes
Have reasonable alternatives been
evaluated?
yes
Allow proposed
activity.
no
Deny proposed
activity.
Complete tier 2 review requirements:
• Ensure existing use protection.
• Show social and economic importance
• Seek public participation.
• Conduct intergovernmental coordination.
Decide whether to allow proposed activity.
8
Will existing uses be maintained and
no
Deny proposed J
protected?
activity. |
yes
Allow proposed
activity.
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§§WP
ANTTDEGBADATtON
How have the States addressed the key antidegradation
Implementation issues?
fasueH): Requirements Applicable to QNRW' Segments (see Box
2 in Figure 2).
State requirements applicable to Outstanding National Resource
Waters (ONRWs) ensure that the water quality of ONRWs is "main-
tained and protected." However, implementation differs from state
to state. In some states, ONRW implementation requirements clear-
ly establish that all new or increased sources of pollutants are prohib-
ited with the limited exception of any activities that would result in
only minor and temporary changes in ONRW water quality. These
states have effectively established outright bans on new or increased
discharges which are not temporary in nature (i.e., regardless of the
quality of the discharge). Such requirements are consistent with the
federal ONRW requirements described in 40 CFR 131.12 and EPA
guidance. Other states allow additional exceptions to the "no new or
expanded discharge" requirement where the quality of the discharge
is sufficient to ensure only minor or no changes in water quality.
One approach is to allow exceptions based on a qualitative signifi-
cance test. For example:
Proposed activities cannot result in significant reduc-
tion of water quality below threshold values as deter-
mined by the Department. (6)
A similar approach is to determine the acceptability of new sources
based on the likelihood of "measurable" change. Fbr example:
If the waterbody is an ONRW, the state cannot allow any
measurable degradation of the present water quality. (5)
Another similar approach is to allow new or increased discharges
provided that the quality of the discharge is equal to, or better than,
background water quality. For example:
Effluent limits for substances in the new or increased
portion of the discharge will be set equal to the back'
ground levels of these substances upstream of, or adja-
cent to, the discharge site unless it is determined that
for tributaries to Great Lakes w ters, such limitations
would result in significant lowering of water quality.
(14)
1 This discussion uses the term ONRW consistently, but not all states use this
term to identify their tier 3 waterbodies.
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A quite different approach used by a few states is to allow exceptions
to the "no new or expanded discharges" requirement based on a
showing that the discharge results in a net benefit to the waterbody.
For example:
Proposed activities may be allowed where they help
maintain or enhance the resource for its designated use
(eg., water treatment facility effluent; weed or algae
control; discharges necessary to provide public access or
otherwise maintain the area). (2)
With respect to nonpoint sources, except where nonpoint sources
are regulated activities, state implementation procedures generally
cite the need to apply best management practices. For example:
Nonpoint sources shall be minimized by application of
BMPs as specified in the state Nonpoint Source Pollution
Assessment and Management Program. (3)
In summary, states implement requirements to "maintain and pro-
tect" the quality of ONRWs using one of two basic approaches: (1)
bans on all new or increased sources that are not temporary in
nature, and (2) bans on new or increased sources that would lower
ambient water quality. All state implementation approaches ensure
that an extra level of protection is afforded to ONRWs. However, a
variety of review criteria is used to determine whether to allow pro-
posed activities located adjacent to, or upstream of. ONRW waters.
Issue (2): Identifying High Quality (Tier 2) Waters (see box 4 in
Figure 2).
A variety of approaches is used by the states to identify high
qua!it" waters subject to tier 2 protection. The federal water quality
standards regulation requires application of tier 2 "where the quality
of the waters exceeds levels necessary to support propagation of
fish, shellfish, and wildlife and recreation in and on the water."
However, the federal regulation does not include specific guidelines
for implementing this requirement. EPA guidance also does not
advocate one specific implementation approach. Consequently,
state procedures do not interpret and implement this requirement in
a consistent manner.
Two basic state approaches exist for identifying high quality waters:
(l)a parameter-by-parameter approach, and (2) a waterbody-by-
waterbody approach. The first approach considers whether water
quality exceeds applicable criteria for each individual parameter that
would be affected by the proposed activity. Thus, available assimila-
tive capacity for any given parameter is always subject to tier 2 pro-
tection regardless of whether the criteria for other parameters are
satisfied. States following the second approach use a variety of tech-
: i/;
69
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AKTtoEGfiADATto*
GUTOAN<£§,
niques (qualitative, quantitative, or both) to determine if, based on its
overall water quality, a segment should be afforded tier 2 protection.
Such determinations may be made prior to the antidegradation
review (i.e., the state may assign high quality designations in the
state standards), or during the course of the antidegradation review.
Under this waterbody-by-waterbody approach, sometimes referred
to as the "designational" approach, assimilative capacity for a given
parameter may not be subject to tier 2 protection if. overall, the seg-
ment is not deemed high quality.
States following a parameter-by-parameter approach generally begin
by identifying all parameters in the proposed discharge that are like-
ly to lower water quality. For each of these parameters, the state
determines whether existing ambient water quality exceeds applica-
ble water quality criteria (i.e., if assimilative capacity exists). If
assimilative capacity exists for any of these parameters, tier 2
requirements would apply to that assimilative capacity and the pro-
posed activity. For example:
Baseline quality should be determined for each parame-
ter in the discharge likely to degrade water quality.
Baseline water quality is defined as the best quality of
the receiving water that has existed since 1968 (under
state resolution 68-16) or since 1975 (underfederal regu-
lation) unless subsequent lowering was due to regulato-
ry action consistent with state and federal requirements,
in which case the baseline quality is the most recent
water quality resulting from the permitted action. If
baseline water quality is better than the water quality
as defined by the water quality objective, the baseline
water quality shall be maintained unless poorer water
quality is necessary.... (19)
States following the second basic approach (i.e. the waterbody-by-
waterbody approach) to identifying high quality waters must judge
the overall quality of the segment (i.e., considering all parameters for
which numeric criteria have been set or other factors). These states
may make these determinations as part of the water quality stan-
dards review process and designate a segment as high qualit" (i.e., a
designational approach). Whether or not a designation is made in
the state standards, these states employ a variety of qualitative and
quantitative tests to determine, overall, if a given segment should be
treated as a high quality water.
One tool that can be used in conjunction with a waterbody-by-water-
body approach is to establish an indicator parameter test for identi-
fying high quality waters. These tests differ in the number of para-
meters included, the percentage of the parameters that must be pre-
sent at quality better than standards, and the frequency with which
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the standards for the parameter must be satisfied. For example,
compare the following tests:
Waters shall be designated by the Commission high qual-
ity 2 if the existing quality for two or fewer of the fol-
lowing twelve parameters is worse than the aquatic life
and recreation, numeric standards: dissolved oxygen, Ph,
fecal coliform, cadmium, copper, iron, lead, manganese,
mercury, selenium, silver, and zinc. (16)
and:
High quality waters are defined as those waters where
existing quality generally exceeds one or more of the fol-
lowing water quality criteria: dissolved oxygen, fecal
coliform, color, or turbidity. AU waters will be consid-
ered as high quality waters unless the applicant can
prove otherwise to the satisfaction of the Department.
(6)
Another waterbody-by-waterbody approach is to base application of
tier 2 protection on the classified uses of the segment. For example:
Tier 2 applies to segments classified Jbr fish and aquatic
life protection. Tier 2 applies to waters not designated
for fish and aquatic life protection where a proposed
activity would result in significant degradation in down-
stream fish and aquatic life waters, exceptional resource
waters, or Great Lakes waters. (14)
A third waterbody-by-waterbody approach for identifying high quali-
ty waters is to base such judgments on the overall value of the
resource. For example:
Waters shall be designated high quality 2 if the waters
are located in a National Park, National Monument,
National Wildlife Refuge, or a designated Wilderness
area; or if the waters are part of a designated wild river
under the Federal Wild and Scenic Rivers Act; or if the
Commission determines that exceptional reasons are
present to warrant the extra protection of uses provided
by the high quality 2 designation. (16)
A difficult issue all states must face regardless of whether a parame-
ter-by-parameter or a waterbody-by-waterbody approach is followed
concerns defining when assimilative capacity exists. In most cases,
ambient monitoring data are limited, and where data are available
they usually represent only the summer "critical" period when water
quality is at its lowest levels. What about water quality during the
rest of the year? Should antidegradation be applied to protect assim-
ilative capacity during the winter months (when flow and water qual-
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icy are often different), even if no assimilative capacity exists during
the critical summer months? One approach is to reference the defin-
ition of assimilative capacity to critical conditions. For example:
The remaining assimilative capacity is the increment of
water quality between that required by the minimum
standards of the waterbody's classification and a reason-
able estimate of existing water quality conditions during
7Q10 stream/low conditions. P)
Another approach, less frequently employed, is to recognize that
assimilative capacity which exists at other times of the year is also
worthy of protection. For example^ one of the approaches described
above would require application of tier 2 where the existing quality
for any of four indicator parameters "generally" exceeds applicable
criteria. Another example of state implementation language that
may allow for protection of cold weather assimilative capacity is the
following:
The baseline water quality (for purposes of determining
assimilative capacity) should be representative of the
waterbody, accounting for temporal and spatial variabil-
ity. (19)
Not all state procedures include a separate definition of assimilative
capacity developed for purposes of antidegradation tier 2. These
states may rely on procedures developed to support TMDLs and/or
derivation of permit limits. For example:
Waters with quality higher than standards will be identi-
fied by the Division on a case-by-case basis through the
NPDES permitting and wasteload allocation processes.
In summary, identifying high quality waters is not necessarily a
straight-forward exercise. As the examples noted above demonstrate,
a variety of approaches are currently employed by the states to
decide which parameters/waters merit tier 2 protection.
Issue (51; Defining Degradation or Lower Water Quality (see Box
The single task associated with antidegradation implementation
which seems to have generated the widest variety of state approach-
es is determining whether a proposed activity will degrade water
quality to an extent that justifies application of tier 2 protection.
Since characterizing the full array of approaches would entail
describing practically all of the state approaches reviewed, only a
sampling of the more significant state approaches are mentioned
below.
(13)
5 in Figure 2)
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«S^
The simplest approach is to define degradation as any lowering of
water quality. For example:
Degradation is defined, as occurring whenever the level
of coliform bacteria, dissolved oxygen, toxic and delete-
rious substances, or radionuclides in surface water
where quality is higher than standards would become
worse as a result of a proposed activity. Temporary
changes in surface water quality resulting from short-
term construction or rehabilitation activities are not
considered degradation. (17)
A fundamentally different approach is to define significant degrada-
tion based on a case-by-case determination which addresses a num-
ber of relevant factors. For example:
The Commissioner will make a determination of whether
a proposed discharge or activity will result in a signifi-
cant change in water quality by utilizing all available
data and the best professional judgment of DEP staff.
Factors to be considered include, but are not limited to:
(a) percent change in a water quality parameter; (b)
quality and value of the resource; (c) cumulative impact
of discharges and/or activities on water quality; (d)
impact on aquatic biota and habitat; (e) eutrophic
impacts; (f) impact on existing and potential uses; and
(g) percent of remaining assimilative capacity for the
water resource. (1)
Quantitative significance tests are also used; these tests range from
simple to complex. For example, Arizona considers any increase in
baseline conditions of five percent or greater significant degradation;
increases less than five percent are not significant degradation.
More complicated quantitative significance tests have also been
developed. For example, the draft Massachusetts procedures include
specific rules for 14 discharge categories and quantitative "thresh-
olds" for 8 pollutant categories (e.g., all new or increased sources of
industrial process wastewater and domestic wastewater are consid-
ered significant and subject to tier 2 requirements). Other discharge
categories are evaluated for significance based on the quantitative
pollutant "thresholds'* (e.g., BOD impacts on dissolved oxygen con-
centrations greater than 1 mg/1 are considered significant).
Some states use a combination of quantitative and qualitative tests
to define significant changes in water quality. Consider the following
examples:
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epa region vw :;«>
amtioegradatiow
Sources of new or increased discharges of pollutants or
te^ealSaaMSi relocation of a discharge that would consume 10% or
more afthe remaining assimilative capacity of the
receiving water shall be considered significant. A dis-
charge which would consume Jess than 10% of the
remaining assimilative capacity wiQ be subject to a case-
by-case review considering the degree of degradation
that has been permitted previously, the sensitivity of the
particular waterbody, public comments and other rele-
vant factors. (J)
and:
Significance determinations are made taking into
account any environmental benefits resulting from the
activity and any water quality-enhancing mitigation
measures impacting the segment or segments under
review. Activities shall be considered insignificant if any
one of four tests are satisfied: (I) dilution is greater
than 100:1 at low flow; (2) the new or increased loading
is less than 10 percent of the existing total load to the
segment for critical constituents, provided that the
cumulative impact of increased loadings from all sources
does not exceed 10 percent of the baseline total load; (3)
the new or increased loading will consume less than IS
percent of available assimilative capacity for critical
constituents; or (4) the activity will result in only tem-
porary or short term changes in water quality. (empha-
sis added, 16)
State tests of significance often vary depending upon the type of pol-
lutant. For example, the draft New Hampshire procedure would
require consideration of the parameter's persistence, synergistic
effects, and environmental accumulation. Other states use a more
quantitative approach. Consider the following examples:
For persistent toxics, addition of any amount is consid-
ered to significantly degrade water quality;for other
substances, addition of an amount greater than 5% of
one half the remaining assimilative capacity is consid-
ered to significantly degrade water quality. (7)
and:
For a new or increased discharge to Great Lakes waters
or their tributaries, a proposed activity will be consid-
ered significant if the mass loading of any substance
with a BAF greater than250 would be increased. (14)
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Another approach defines significance based on the error associated
with the analytical method. For example:
Significant degradation will be presumed unless the
applicant demonstrates that the concentration of the
parameter under consideration can be expected to
increase (or decrease) by less than the error that is
inherent to the technique that is normally used to mea-
sure the parameter (these techniques are normally
approved by EPA wider 40 CFR 136). Par example, an
expected change in dissolved oxygen of less than 02 mg/l
would not be considered a significant change, since the
DO test is considered accurate to only ±.0J2 mg/L (10)
Finally, some states limit their evaluation of significance to a subset
of the parameters that may be affected by the proposed activity.
Pennsylvania, for example, may limit the evaluation to parameters
that are identified as significant for the type of discharge and which
are significant to protection of waterbody uses. Another example is
as follows:
For 10 representative indicator parameters determined
by the Department, the applicant shall determine
expected levels in the discharge, existing ambient back-
ground levels, and expected ambient levels as a result of
. the proposed new or increased discharge. A proposed
activity will be considered significant if it, along with all
other new or increased discharges after March 1, 1989,
results in an expected ambient level of an indicator para•
meter of either of the following: (1) greater than one-
third multiplied by the assimilative capacity for any
indicator other than dissolved oxygen; or (2) greater
than die sum of the existing level multiplied by two-
thirds and the water quality criterion multiplied by one-
third for dissolved oxygen. (14)
In summary, a great variety of approaches is used by states to define
"degradation or lower water quality." Such "significance" tests range
from simple to complex, involve qualitative or quantitative measures
or both, and often vary depending upon the type of parameter or the
accuracy of the analytical method used to measure the parameter.
Issue (41: Existing Use Protection (see Boxes 7 and 8 in Figure 2).
Protection of existing uses is another issue where state imple-
mentation procedures exhibit considerable variability. For purposes
of this discussion, state approaches are organized into two cate-
gories:
(1) approaches to protect existing uses in high quality waters; and
(2) approaches to protect existing uses in non-high quality waters.
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j$MituiiiCK|
Existing use protection in high quality (or tier 2) waters is one of a
number of requirements that must be addressed prior to allowing a
proposed activity to lower water quality. One of the primary ques-
tions that must be addressed is whether or not to rely on designated
uses to reflect existing uses. Under the federal water quality stan-
dards regulation, designated uses are required to reflect attainable
water uses (i.e.. including, at a minimum, existing uses). Therefore,
one approach is to rely on the designated uses and associated crite-
ria to reflect levels of water quality necessary to protect existing
uses. This simply requires the regulatory authority to ensure, under
tier 2, that proposed activities will not lower water quality to the
point that criteria are exceeded. For example.
At a minimum, for all state surface -waters existing, clas-
sified uses and the level of water quality necessary to
protect such uses shall be maintained and protected.
The classified uses shall be deemed protected if the nar-
rative and numerical standards are not exceeded. (16)
and:
Even though existing use as defined in the Standards
(definition §12) relies on a finding that actual use has
occurred, it is clear from Sections 3-02,3-05, and 3-04
that water quality is to be maintained regardless of the
fact of existing uses. Therefore in implementing the
antidegradation provisions of the Standards, a level of
water quality to protect potential uses (those recognized
by the classification) will be maintained as well as for
existing uses. The reclassification process will be relied
on to change the level of protection afforded state waters
as may be needed in the public interest. (6)
Another approach is to identify and protect existing uses regardless
of whether the existing use is reflected by the designated use. This
approach allows protection of existing uses where existing water
quality supports a higher use than is designated for the waterbody.
Because formal reclassification of waters is often a time-consuming
exercise, states using this approach require protection of existing
uses in tier 2 waters without awaiting a formal reclassification action
for the waterbody. Consider the following examples:
¦Existing uses" is defined in Rule 17-3.021(14) to mean
any actual beneficial use of the waterbody on or after
November 28, 1975. Therefore if there is conclusive evi-
dence that a bay had been used for shellfishing in the
late 1970s, dischargers could presently be required to
meet Class n requirements even if the waterbody has
always been and presently is classified as Class m. (12)
and:
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This antidegradatkm provision requires that when the
actual water quality of any waterbtxfy exceeds the mini-
mum requirements of the next higher Class, that the
higher water quality wia be maintained and protected.
If the Departments water quality investigation and
assessment report finds that the actual water quality of
a waterbody is meeting all the minimum requirements of
the next classification, and the Board concurs with the
Department's report, then the Board and the Department
shall treat that waterbody as if the next highest classifi-
cation is assigned to that waterbody and the Board shall
recommend to the next regular session of the Legislature
that the water be reclassified in the next highest classifi-
cation. (emphasis added, 3)
Another issue related to existing use protection is determining
appropriate measures of attainment. A key element of such deter-
minations is whether water column concentrations are the sole mea-
sure by which existing use protection is to be gauged. As discussed
above, one approach is to rely on the designated uses and their asso-
ciated criteria (which generally focus on water column concentra-
tions) to protect existing uses. Another approach is to broaden exist-
ing use protection to measure and address impairments resulting
from non-water column factors. Consider the following examples:
Existing use protection is intended to allow the consid-
eration of certain circumstances not addressed by the
narrative and numerical standards. For example, there
are reasons other than lowering of water quality that
may be the cause of a discharger's adverse impact. Such
reasons could include physical impacts, such as scouring
of seagrass, that may adversely effect fish and wildlife
habitat in certain situations. Also, there may be situa-
tions where lowering of water quality, even though kept
within standards, wHl adversely affect fish and wildlife
habitat or recreation. If the applicant has shown that
the water quality standards would be met, DER must be
able to document a reasonable scientific basis for its
prediction that the proposed activity would impair one
or more of the waterbody uses before requiring the
applicant to further address this issue. (12)
and:
The policy defines significant impact to existing uses as
impairing the viability of the existing population,
including significant impairment to growth and repro-
duction or an alteration of ¦die habitat which impairs
viability of the existing population. (3)
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ANTtotGaADATioH
Existing use protection in non-high quality (tier 1 only) waters is of
critical importance because it is the only antidegradation require-
ment restricting further impairment of such waters (i.e., the alterna-
tives analysis, socio-economic importance, and other tier 2 require-
ments are not applicable). Although water quality may be signifi-
cantly impaired in such waters, necessitating different methods to
derive control requirements (e.g.. Total Maximum Daily Loads and
water quality-based permit limits), the antidegradation procedure for
protection of existing uses may be identical as that used for tier 2
waters. For example, the primary task is still to determine whether
uses have existed, at some point after 1975, that have more strin-
gent water quality requirements than the currently designated uses.
Addressing this question is fully consistent with the federal water
quality standards regulation which, at § 131.3(e), defines existing
uses as follows:
Existing uses are those uses actually attained in the
waterbody on or after November 28, 1975, whether or
not they are included in the water quality standards.
Deriving effluent limits sufficient to protect existing uses may be dif-
ferent in non-high quality waters in that the criteria for the parame-
ter of concern may already be exceeded (i.e.. there is no assimilative
capacity). This is especially likely where the state procedures follow
a parameter-by-parameter approach to identifying high quality tier 2
waters (see Issue (2) discussed above). Where no assimilative capac-
ity exists, protection of existing uses depends upon implementation
of controls to ensure that water quality will protect existing uses
fully. Pursuant to CWA § 303(d), states are required to develop such
controls based on a Total Maximum Daily Load (TMDL) Analysis.
In summary, approaches to protect existing uses vary among the
states. The two key issues which have attracted a variety of
approaches are (1) whether to rely on the designated uses of a seg-
ment to also reflect existing uses and (2) whether (and how) to
address impacts to existing uses resulting from non-water column
influences.
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APPENDIX 3:
EPA REGION VIII RESPONSES TO
MAJOR COMMENTS
¦HVfc .
The following questions and comments were received by the Region
in response to several earlier drafts of this guidance.
Why is EPA Region VIII establishing a minimum requirement that
antidegradation reviews be conducted for "regulated activities"?
Won't this leave out many nonpoint sources?
This was the single most difficult issue which arose in developing
this guidance document. On the one hand. EPA Region VIII believes
that water quality standards can and should be applied by states to
all activities that affect water quality. On the other hand, many states
have not yet adopted control regulations applicable to nonpoint
sources, preferring to address nonpoint sources through voluntary
programs. Since most state water quality standards are not self-
implementing, states are typically left without a regulatory ability to
control nonpoint sources. EPA Region VIII does not believe that a
state antidegradation policy, in and of itself, necessarily creates a
regulatory requirement to control nonpoint sources. EPA Region VIII
also does not believe that the Clean Water Act. as interpreted by EPA
regulations at 40 CFR 131, creates a federal requirement for states to
regulate nonpoint sources such that water quality standards and anti-
degradation requirements are satisfied. The Region does believe
that, even in states where many activities that result in nonpoint
sources are not regulated, there is a role for water quality standards
and antidegradation in promoting voluntary water quality manage-
ment efforts. EPA Region VIII also encourages states to apply anti-
degradation broadly (in a regulatory sense) to all activities that may
degrade water quality (see additional discussion of this issue in
Chapter 4 of this guidance).
How should antidegradation tier 2 be applied to nonpoint sources?
The process would be very similar for proposed point and nonpoint
sources. Following the antidegradation implementation flow chart
(see page 8). the first step is to determine whether the segment is a
high quality water. This step would be the same for point and non-
point sources. The next step, to determine whether the proposed
activity would result in "significant degradation," is somewhat more
difficult for nonpoint sources because of the difficulty of predicting
effects (such as pollutant loadings) of future nonpoint sources. EPA
suggests that states rely on their experience and information on
effectiveness of various BMPs in determining significance. As for
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spabegiohvu
AWTtDicaAiw
guiw
point sources. EPA Region VIII believes it makes sense to establish a
low threshold of significance and to place the burden on the project
applicant to prove that the proposed activity will not degrade water
quality. In terms of identifying the least degrading alternative (i.e., is
the degradation "necessary"), states may rely on their CWA § 319
nonpoint source management plans to identify the best manage-
ment practices that are appropriate for the particular nonpoint
source. However, follow-up monitoring of the effectiveness of in-
place BMPs is critically important to improve the ability of the state
to select the least-degrading alternative and minimize impacts of
nonpoint sources pursuant to tier 2 requirements. As for point
sources. Region VIII believes that the evaluation of alternatives is the
appropriate focal point of tier 2 implementation efforts for nonpoint
sources. The remaining components of a tier 2 review for proposed
nonpoint sources would be very similar to such reviews for point
sources. Additional discussion of how water quality standards apply
to nonpoint sources can be found in EPA's Water Quality Standards
Handbook.
Does antidegradation only apply to specific parameters limited in
the water quality standards or can it apply to any parameter of con-
cern (e.g., phosphates)?
Antidegradation can and should apply to any parameter of concern,
regardless of whether a numeric standard has been adopted. Fbr a
parameter such as phosphates, for which the narrative standards are
likely to be the basis for control actions, antidegradation should still
be applied. For example, under Part vl(B)(2)(c) of the model proce-
dure, the proposed new or expanded effluent loadings of phosphates
can be the basis for concluding that significant degradation will
occur. As for determining necessity, many states have concluded
that a ban on the discharge of phosphates is appropriate; and thus,
under antidegradation tier 2, considering source reduction and pollu-
tion prevention alternatives would be appropriate.
How does EPA Region VIII plan to implement this guidance for activi-
ties on Indian lands?
EPA Region VIII stands ready to assist Indian tribes with establishing
appropriate water quality standards and antidegradation programs
on reservations. Consistent with the Agency's 1984 Indian Policy, the
Region will work directly with tribal governments and will encourage
and assist tribes to assume water quality standards program man-
agement responsibilities for reservation lands. EPA Region Vlll's per-
spective on establishing water quality standards on reservations is
discussed in more detail in EPA Region VIII Interim Guidance: Water
80
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Quality Standards for Indian Tribes, January 1993, copies of which are
available from the Region.
In the model implementation procedure, there is too much left to
best professional judgment — the procedure will not insure consis-
tent decisions in future reviews.
The Region acknowledges that the model procedure relies heavily on
best professional judgment to make the various decisions associated
with implementing antidegradation requirements. Although the pro-
cedure includes guidelines and discussion to lead the reviewer
through the process, the Region intentionally left many of the deci-
sions to best professional judgment so that unique circumstances
specific to each case can be considered. To further explain how the
procedure should be applied, the Region has developed and incorpo-
rated into the model procedure questions and answers to address
specific scenarios. The Region recommends that states use this
"case example" technique to communicate to dischargers and the
public how the various antidegradation findings will be made.
The timing of the evaluation of alternatives required under tier 2 will
occur after many projects have already undergone extensive evalua-
tion. By the time a review is performed, the project may be too far
advanced to make any less-damaging alternative reasonable.
The Region agrees that the timing of antidegradation reviews may be
a problem. However, the problem can be avoided or at least mini-
mized by making sure that potentially affected parties are aware of
antidegradation requirements. Distributing a detailed implementa-
tion procedure can help inform such parties about the overall pur-
pose and philosophy of antidegradation as well as the specific steps
and requirements that will be applied in reviewing proposed activi-
ties. Public outreach is thus an important aspect of antidegradation
implementation.
The guidance should address the special problems of ground water
and the effects discharges to ground waters may have on surface
waters.
Although states have flexibility to apply regulatory requirements to
activities affecting ground water quality, such regulatory require-
ments are not mandated by the federal Clean Water Act. However,
activities that may potentially affect surface water quality via a con-
nection through groundwater may be subject to antidegradation
requirements and regulation under the Clean Water Act. EPA
^BPWNDiX*!;
s'v v '
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>V/* jrS.
encourages states to apply their antidegradation requirements broad-
ly to all activities that affect either surface or ground water quality.
The guidance should further discuss the purpose of antidegradation.
The guidance sends mixed messages; on the one hand saying that
degradation is not allowed and on the other setting up conditions
under which it can be allowed. We object to use of "assimilative
capacity" as it presupposes an intent to allow water quality to deteri-
orate up to the point where standards are about to be violated.
The Region believes that the commenter may have misunderstood
the intended purpose of federal tier 2 requirements. It is true that
the stated purpose of tier 2 in the federal water quality standards
regulation is to "maintain and protect" existing high quality waters.
However, tier 2 was never intended to be an absolute barrier to
degradation except where, for example, a proposed activity has no
social/economic importance or where the proposed degradation is
not "necessary" because of the availability of reasonable less-degrad-
ing or non-degrading alternatives. The basic function of tier 2 is to
ensure that, where degradation occurs, it occurs for a good reason
and is minimized in a reasonable manner, subject to public review.
Thus, tier 2 is not intended to be an absolute barrier to degradation
but rather a process to carefully consider whether allowing the
degradation makes sense. The Region agrees that application of tier
2 will not necessarily preserve high quality waters at their existing
quality indefinitely. For waters where long-term preservation of
existing water quality is determined to be important. EPA suggests
that states apply either an antidegradation tier 3 or tier 2.5 designa-
tion. Another option to preserve existing water quality in high quali-
ty waters is to apply the Total Maximum Daily Load (TMDL) program
in a conservative manner. Because TMDLs are legally required to
include a margin of safety (MOS), the TMDL is another option by
which existing assimilative capacity can be preserved and protected.
Fbr OSRW segments and discharges upstream of ONRW segments,
what does EPA mean by "no effect"?
This commert add**;sses e fact that, on the one hand, discharges
to OSRW segments and discharges upstream of ONRW segments are
required to have no effect on water quality, and on the other hand
factors (e.g., percent change in ambient concentrations, degree of
confidence in the modeling technique utilized) are established to
guide the decision. By establishing these factors, it was intended
that the model procedure include a de minimis change threshold.
EPA Region VIII believes that establishing such a threshold is appro-
priate and that extremely small projected changes in water quality
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should not necessarily be grounds for prohibiting a proposed activity.
The procedure includes the requirement for no effect to make clear
that only truly miniscule projected changes in water quality should
be excluded from consideration. The Region believes that as confi-
dence in the projected water quality effects gets worse, the de min-
imis change threshold should get progressively lower (more restric-
tive). However, under no circumstances should an activity be
allowed that is likely to result in a real change in water quality in an
ONRW segment.
The proposed guidance advocates triggering of antidegradation
when permitted effluent quality is increased, but what about munici-
palities with 20 year growth plans where the permit was written
based on optimistic growth forecasts? Would antidegradation ever
be triggered for such facilities?
The Region acknowledges that many PCTWs were designed based
on optimistic population growth forecasts and as a result have "per-
mitted" loading rates that gready exceed "existing" loading rates. To
address these and other situations, the guidance has been revised to
recommend consideration of existing versus permitted effluent qual-
ity when judging "significant degradation." This factor will allow
states to conclude significance even where there would be no
increase in permitted loadings. The Region anticipates that some
consideration of EEQ should be included in an antidegradation
review, particularly where persistent toxics are of concern and where
there may be pollution-prevention alternatives that could result in
elimination of the parameters of concern from a facility's effluent.
The bottom line requirements are not specific enough; where will
EPA draw the line?
As explained in Chapter 3, the "bottom line" requirements are
intended only to ensure that state and tribal antidegradation imple-
mentation procedures are sufficiendy developed to promote effective
implementation. To this end. Chapter 3 includes a list of the specific
issues that must be addressed and clearly resolved by such state and
tribal procedures. On ail of the issues, there is a range of approaches
that would be acceptable to EPA. On any given issue, it is difficult to
say where EPA's "line" is drawn; in general, EPA intends to provide
states with the flexibility to implement innovative approaches.
Where possible, EPA has included specific minimum requirements in
Chapter 3 to identify potential disapproval items. However, on all of
the issues, EPA reserves the right to review the specifics of a state or
tribal implementation procedure prior to coming to a conclusion
iwiNoocva
hS//S>Xyet/AA
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regarding approval. In the absence of specifics, EPA Region VIII can-
not guarantee that any particular approach would be approved.
For direct discharges to ONRWs, why is EPA prohibiting a discharge
that is equal to or better than background quality?
The basic requirement applicable to ONRWs is that they be main-
tained at their existing water quality. For a variety of reasons, EPA
Region VIII does not believe that activities that will result in a new or
expanded direct source of pollutants to an ONRW segment should be
allowed. The Region acknowledges that in certain ONRWs, back-
ground water quality concentrations may be naturally "high" for
some parameters. It is conceivable that a new direct source of one
of these parameters would have a lower concentration than the
existing background concentration and would thus lower the ambi-
ent concentration downstream of the new source. However, to the
extent that maintaining "natural" conditions is a goal, any change,
whether an increase or a decrease, may not be desirable. Also, it is
impossible to guarantee the quality of new sources of pollutants.
Effluent variability, operator errors, and treatment process upsets are
facts of life. For these reasons, EPA Region VIII believes that main-
taining the quality of ONRWs requires an absolute prohibition on
new or expanded direct sources of pollutants, regardless of the quali-
ty of such sources.
The guidance should recommend that tier 2 not be applied to all
waters not meeting uses according to CWA § 305(b), § 314 and §
319 assessments.
EPA Region VIII disagrees that assessments conducted under CWA §
305(b), § 314, or § 319 should be the basis for identifying high quali-
ty waters. The primary overall reason is that the threshold used to
conclude "Impairment" for purposes of these assessments may be
substantially lower than is appropriate for identifying non-high quali-
ty or tier 1-only waters. As explained in Chapter 2. EPA Region VIII
believes that tier 2 should be applied to a very large majority of state
waters. In order to preserve high levels of water quality for parame-
ters where existing quality is setter than star.Jards, the threshold of
impairment for excluding waters from tier 2 (based on chemical-spe-
cific information) should be higher than for purposes of assessments
such as those conducted under CWA § 305(b). Thus, Region VIII
believes that tier 2 should be applied even where the criteria for
some parameters are not always satisfied. Under assessments con-
ducted under § 305(b). § 314, or § 319, a segment may appropriate-
ly be listed as "impaired" based on very limited data, and the
impairment may be based on a single violation or the potential
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effects of a single parameter. Also, to support the antidegradation
analysis, the applicant may provide new data not available at the
time of the § 305(b). § 314. or § 319 assessment that should be con-
sidered. Rather than focussing in on theoretical impairments result-
ing from single parameters, the Region believes that high quality
waters should be identified based on an integrated assessment of
the most recent chemical, physical, and biological data. For these
reasons EPA Region VIII believes that information from these previ-
ously-completed assessments should be considered, in implementing
antidegradation, but they should not be the sole basis for concluding
that a particular segment is not a high quality water.
The guidance should include a more detailed definition and proce-
dure for determining ambient water quality to serve as the basis for
identifying high quality waters and significant degradation.
The recommended approach is driven by the Region's belief that it is
critical to focus available antidegradation review resources on the fol-
lowing question: Are reasonable non-degrading or less degrading alter-
natives available? The Region suggests that state and tribal tier 2
implementation efforts concentrate on responding to this question.
The Region has intentionally not established a recommended mini-
mum data base to define ambient conditions because of the possibil-
ity that acquiring such data might be viewed as a necessary prereq-
uisite to making the high quality and significant degradation deter-
minations. As explained in Chapter 4, EPA Region VIII recommends
that states and tribes focus their efforts on the evaluation of alterna-
tives and to pursue such evaluations for most proposed activities.
This focus is most effectively achieved by addressing the high quality
and significance questions as simply as possible and by establishing
a rebuttable presumption that all waters are high quality and that ail
proposed activities will result in significant degradation. In many
cases, making the high quality water and significance determina-
tions should not prove to be difficult or data-intensive. In general,
state TMDL procedures should be utilized to define existing ambient
water quality conditions. Data that are necessary to make these
determinations should be required of the project applicant.
However, where data are sufficient to suggest that significant degra-
dation of a high quality water will occur, an evaluation of alternatives
should be required of the project applicant.
For purposes of determining significant degradation, why does EPA
recommend use of the projected pollutant loadings instead of pro-
jected effluent/ambient concentrations? For example, if the quality
of a proposed new discharge to a high quality water is equal to or
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(w)
better than background water quality, when would an antidegrada-
tion review be necessary?
Information on both pollutant concentrations and loadings will be
useful in judging significance. In some cases, a simple comparison
of proposed versus existing effluent loadings will be sufficient basis
to conclude that a significant change in water quality will result. In
these cases, information on background water quality and modeling
the potential change in water quality are not necessary to conclude
significance. With regard to the cited example, where the quality of
a proposed discharge is equal to or better than background water
quality, the state would be correct in determining no significant
degradation, except perhaps where a cumulative effect is of concern,
such as may be the case with persistent toxics in fish or sediment.
Why does Region VIII recommend a waterbody-by-waterbody
approach to defining high quality waters? Given the potential
impacts of tier 2 requirements on dischargers, a parameter-by-para-
meter approach may be necessary to justify additional controls.
Both the waterbody-by-waterbody and the parameter-by-parameter
approaches for identifying high quality waters are commonly used
by states nationally, and either would be supported by EPA Region
VIII. However, as explained in Chapter 4, Region VIII suggests that,
generally, implementation of the federal requirement to apply tier 2
where "the quality of the waters exceed levels necessary to sup-
port..." (see 40 CFR 131.12(a)(2)) is best accomplished by focussing
on segments where fishable/swimmable uses are attained. Note that
waters which are not "swimmable" could still be high quality for pur-
poses of "fishable" uses and vice versa. This approach allows high
quaiit" water determinations to be based on an integrated assess-
ment of chemical, physical, and biological monitoring information,
and it allows states to focus antidegradation review efforts on the
higher-value state waters. The Region also believes that a high per-
centage of waters should qualify for tier 2 protection under this
approach and that states should presume that its waters are high
quality until proven otherwise. In addition, as discussed above, the
Region does not believe that exceedences for one or two parameters
should neces-drily be a basis for concluding that a segment is not
high quality (see comment #13). Thus, states should consider ail
available information and make an overall determination regarding
whether a segment is high quality. However, the Region would like
to emphasize that states may elect to apply a parameter-by-parame-
ter approach as an effective means of identifying high quality waters
and of protecting assimilative capacity wherever it occurs. Within
the Region's model procedure, a parameter-by-parameter approach
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is applied for purposes of determining significant degradation. That
is, prior to proceeding with the evaluation of alternatives, it is first
determined that significant degradation is likely to result for one or
more parameters. Hence, the Region recommends that implementa-
tion of tier 2 requirements should involve both an overall assessment
of whether water quality "exceeds levels necessary" to support fish-
able/swimmable uses as well as a parameter-by-parameter assess-
ment of whether water quality is likely to be significandy lowered by
the proposed activity.
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