[Federal Register Volume 60, Number 15 (Tuesday, January 24, 1995)]
[Rules and Regulations]
[Pages 4664-4709]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-817]
[[Page 4663]]
_______________________________________________________________________
Part II
Environmental Protection Agency
_______________________________________________________________________
40 CFR Part 131
Water Quality Standards for Surface Waters of the Sacramento and San
Joaquin Rivers, and San Francisco Bay and Delta, California; Final Rule
Federal Register / Vol. 60, No. 15 / Tuesday, January 24, 1995 /
Rules and Regulations
[[Page 4664]]
ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 131
[OW-FRL-5084-4]
Water Quality Standards for Surface Waters of the Sacramento
River, San Joaquin River, and San Francisco Bay and Delta of the State
of California
AGENCY: Environmental Protection Agency.
ACTION: Final rule.
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SUMMARY: This final rule, required under Section 303 of the Clean Water
Act, is part of an interagency effort designed to ensure that the fish
and wildlife resources of the San Francisco Bay/Sacramento-San Joaquin
Delta Estuary (Bay/Delta) are protected and to minimize the likelihood
of future listings of Bay/Delta species under the Endangered Species
Act. The Bay/Delta is the West Coast's largest estuary, supplying
habitat for over 120 fish species and large populations of waterfowl.
Over the past two years, the U.S. Environmental Protection Agency (EPA)
has worked closely with the Departments of the Interior and Commerce,
as well as the State of California, to address the severe and
continuing decline of Bay/Delta fish and wildlife resources. This
decline has been so severe that a number of fish species, including the
winter-run chinook salmon are considered threatened or endangered under
the Endangered Species Act. In coordinating their respective actions in
the Bay/Delta, the Federal agencies endorsed an ecosystem (as opposed
to a species-by-species) approach. EPA's final rule establishes four
sets of water quality criteria protecting habitat conditions in the
estuary.
EFFECTIVE DATE: This rule shall be effective February 23, 1995.
ADDRESSES: The public may inspect the administrative record for this
rulemaking, including documentation supporting the criteria, and all
public comments received on the proposed rule at the Environmental
Protection Agency, Water Management Division, 11th Floor, 75 Hawthorne
Street, San Francisco, California 94105 (Telephone Sara Hedrick at 415-
744-2200) on weekdays during the Agency's normal business hours of 9
a.m. to 5 p.m. A reasonable fee will be charged for photocopies.
Inquiries can be made by calling Sara Hedrick at 415-744-2200.
FOR FURTHER INFORMATION CONTACT: Judy Kelly, Bay/Delta Program Manager,
Water Management Division, W-2-4, Environmental Protection Agency, 75
Hawthorne Street, San Francisco, California 94105, 415/744-1162.
SUPPLEMENTARY INFORMATION: This preamble is organized according to the
following outline:
A. Background
1. Introduction
2. Background
a. Environmental Concerns
b. State Designation of Uses in the Bay/Delta
c. EPA Activity Under Clean Water Act Section 303
d. Post-Proposal Activities
B. Statutory and Regulatory Background
C. Description of the Final Rule and Changes From Proposal
1. Estuarine Habitat Criteria
a. Overview
b. Detailed Discussion
(1) Proposed Estuarine Habitat Criteria
(2) Technical Changes to the Estuarine Habitat Criteria
(i) Underlying Computational Revisions
(ii) Using a Sliding Scale
(iii) Moving to Monthly Compliance
(iv) Alternative Measures of Attaining the Criteria
c. Revised Estuarine Habitat Criteria
2. Fish Migration Criteria
a. Overview
b. Detailed Discussion
(1) Proposed Rule
(2) Final Fish Migration Criteria
(i) Revised Method of Selecting Criteria Index Values
(ii) Use of Continuous Function
(iii) Measuring Attainment Through Actual Test Results
(3) Fish Migration Criteria as Multispecies Protection
3. Fish Spawning Criteria
a. Proposed Rule
b. Comments on Proposal and Final Criteria
4. Suisun Marsh Criteria
D. Public Comments
E. Executive Order 12866
F. Regulatory Flexibility Act
G. Executive Order 12875
H. Paperwork Reduction Act
A. Background
1. Introduction
This section of the Preamble introduces the topics which are
addressed subsequently, provides a brief description of the
environmental issues at stake in the San Francisco Bay/Sacramento-San
Joaquin River Delta Estuary (Bay/Delta), and reviews the U.S.
Environmental Protection Agency's (EPA or the Agency) recent
involvement in these issues. Section B of this Preamble describes the
statutory framework of section 303 of the Federal Water Pollution
Control Act (33 U.S.C. 1251 to 1387) (CWA or the Clean Water Act), as
well as the regulatory process for developing and revising water
quality standards. In addition, Section B summarizes the recent actions
of the State of California (State) and EPA under section 303 of the
CWA. Section C describes the Final Rule, focusing especially on the
changes from the criteria proposed at 59 FR 810, January 6, 1994
(Proposed Rule). Sections D, E, F, G, and H discuss the public
comments, the requirements of Executive Order 12866, the Regulatory
Flexibility Act, Executive Order 12875, and the Paperwork Reduction
Act, respectively.
In addition to publishing the Proposed Rule, EPA, on August 26,
1994, at 59 FR 44095, published a Notice of Availability announcing the
availability of two documents prepared since the close of the comment
period. The first of these documents was a summary of a series of
scientific workshops on EPA's proposed Fish Migration criteria that
were sponsored and facilitated by the California Urban Water Users
(CUWA) and four environmental organizations. The second document was an
internal EPA staff paper presenting a reformulation of the Fish
Migration criteria based upon the comments at the workshops. EPA
accepted public comments on the issues raised in these two documents
until September 30, 1994. EPA received two written comments in response
to the Notice of Availability.
This final rule satisfies EPA's obligations under a settlement
agreement approved and entered as an order in Golden Gate Audubon
Society et al. v. Browner (E.D. Cal. Civ. No. 93-646 (LKK)).
2. Background
a. Environmental Concerns
The Bay/Delta is the West Coast's largest estuary, encompassing
nearly 1600 square miles, and draining over 40 percent of California.
The Bay/Delta is the point of convergence of California's two major
river systems--the Sacramento River system flowing southward and
draining a large part of northern California, and the San Joaquin River
system flowing northward and draining a large part of central
California. These two river systems come together at the western tip of
the Delta, forming an estuary as fresh water mixes with marine water
through a series of bays, channels, shoals and marshes and ultimately
flowing into San Francisco Bay and then to the Pacific Ocean.
The Bay/Delta constitutes one of the largest systems for fish
production in the country, supplying habitat for over 120 fish species.
It also comprises one of the largest areas of waterfowl habitat
[[Page 4665]] in the United States, providing a vital stopover for rest
and feeding for more than one-half of the waterfowl and shorebirds
migrating on the Pacific Flyway. Within the boundaries of the Bay/Delta
is the Suisun Marsh, the largest contiguous brackish water marsh in the
United States.
The Bay/Delta is also the hub of California's two major water
distribution systems--the Central Valley Project (CVP) built and
operated by the U.S. Bureau of Reclamation (USBR) and the State of
California's State Water Project (SWP). These two projects account for
approximately 60% of the watershed's diversions (San Francisco Estuary
Project (SFEP) 1992). In addition, at least 7,000 other permitted water
diverters, some large and some small, have developed water supplies
from the watershed feeding the Bay/Delta estuary (California State
Lands Commission 1991). Together, these water development projects
divert, on average, 50% of the natural flow in the Bay/Delta estuary
(SFEP 1992). Most of the State's developed water--75 to 85 percent--is
used for irrigation purposes by agriculture, irrigating over 4.5
million acres throughout the State. The Bay/Delta watershed also
provides part or all of the drinking water supply for over 18 million
people.
In large part due to the effects of these water diversions, and as
discussed in more detail in the preamble to the Proposed Rule, the fish
and wildlife resources in the Bay/Delta estuary have deteriorated
drastically over the past twenty years. One common measure used to
quantify this deterioration is the Striped Bass Index (SBI) (a measure
of the relative abundance of young striped bass in the estuary). The
SBI measures the relative health of an indicator species for the Bay/
Delta, the striped bass. In its 1978 Water Quality Control Plan (1978
Delta Plan), the California State Water Resources Control Board (State
Board) committed to maintaining an SBI value of 79. Since that time the
SBI has never attained its targeted value of 79, but instead has
plummeted to unprecedented low values.\1\
\1\During the 1980's, the SBI averaged approximately 23.5, and
in 1985 reached an all-time low of 4.3. Some of the decline in the
SBI may be attributable to drought conditions in the late 1970's and
again in the late 1980's. In all but two years since the 1978 Delta
Plan was adopted, the SBI has ranged from 4.3 to 29.1, a substantial
shortfall from the stated goal of 79.
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The precipitous decline in striped bass is indicative of the poor
health of other aquatic resources in the Bay/Delta estuary. Several
species have experienced similar declines, including chinook salmon
(the winter-run of chinook salmon has recently been reclassified as an
endangered species under the Federal Endangered Species Act, 16 U.S.C.
1531 to 1540 (ESA)), Delta smelt (listed as a threatened species under
the ESA), and the Sacramento splittail (recently proposed for listing
as a threatened species under the ESA). The California Department of
Fish and Game (California DFG) recently testified that virtually all of
the estuary's major fish species are in clear decline. (CDFG 1992b,
WRINT-DFG-8)\2\ Another recent report suggests that at least three more
of the Bay/Delta estuary's fish species (spring-run Chinook salmon,
green sturgeon, and Red Hills roach) qualify for immediate listing
under the ESA (Moyle and Yoshiyama 1992). Furthermore, the decline in
aquatic resources is not limited to fishes. One recent workshop noted
that the available data ``indicate clearly that species at every
trophic level are now at, or near, record low levels in the Delta and
in Suisun Bay.''\3\ (SFEP 1993) The ecological communities under stress
include the plant and animal communities in the tidal portions of the
brackish water marshes adjacent to Suisun Bay (Collins, J.N. and T.C.
Foin, 1993).
\2\If a reference was presented to the State Board during one of
its hearings, this preamble will present citations in both the
standard scientific form and in the State Board hearing record form.
Accordingly, the eighth exhibit submitted by California DFG at the
Board's interim water rights hearings in the summer of 1992 is cited
as indicated.
\3\The workshop report went on to state that this low level of
biological diversity was ``not surprising considering the recent
drought, the introduction of exotic species, and the increased
diversion of water.''
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b. State Designation of Uses in the Bay/Delta
Under section 303(c) of the CWA, states review their water quality
standards every three years and submit any new or revised standards to
EPA for approval or disapproval (the ``triennial review''). A water
quality standard for a waterbody consists of two components: (1)
Designated uses for the waterbody and (2) water quality criteria which
support such designated uses.\4\ In California, designated uses are
equivalent to state law ``beneficial uses'' and criteria are equivalent
to state law ``water quality objectives.'' Thus, the water quality
objectives and beneficial use designations adopted under the California
Water Code serve as water quality standards for purposes of section 303
of the CWA.
\4\In addition, a state's criteria must be consistent with the
state's antidegradation policy. The federal regulations provide
that, at a minimum, the state's policy must maintain ``[e]xisting
instream water uses [those existing in the waterbody at any time on
or after November 28, 1975] and the level of water quality necessary
to protect the existing uses. * * *'' 40 CFR 131.12(a)(1).
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Pursuant to state and federal law, the State Board, on May 1, 1991,
adopted State Board Resolution No. 91-34, formally approving the 1991
Bay/Delta Plan. The Plan restated the specific designated uses that had
been included in the 1978 Delta Plan and related regional board basin
plans. As restated in the 1991 Bay/Delta Plan and submitted to EPA for
review under the Clean Water Act, the designated uses for waters of the
Bay/Delta included the following: Agricultural Supply, Cold and Warm
Fresh-Water Habitat, Estuarine Habitat, Fish Migration, Fish Spawning,
Groundwater Recharge, Industrial Process Supply, Industrial Service
Supply, Municipal and Domestic Supply, Navigation, Contact and Non-
Contact Water Recreation, Ocean Commercial and Sport Fishing,
Preservation of Rare and Endangered Species, Shellfish Harvesting, and
Wildlife Habitat.\5\
\5\As explained in more detail below, under certain
circumstances a state may revise or even remove designated uses.
However, in the Bay/Delta context, the State Board has made no
effort to revise the designated uses adopted and restated in the
1991 Bay/Delta Plan.
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c. EPA Activity Under CWA Section 303
As explained in detail in the preamble of the Proposed Rule, the
serious environmental crisis for fish and wildlife resources in the
Bay/Delta has been the source of an ongoing dialogue between EPA and
the State for many years. Pursuant to section 303(c)(3) of the CWA, EPA
reviewed the 1978 Delta Plan in 1980. While EPA approved the Plan, it
was concerned that the 1978 Delta Plan standards would not provide
adequate protection of striped bass and the estuary's fishery
resources. EPA therefore sought and received assurances from the State
Board as to the interpretation of the standards, and secured the State
Board's commitment to review and revise the 1978 Delta Plan standards
immediately if there were measurable adverse impacts on striped bass
spawning, or if necessary to attain ``without project'' levels of
protection for the striped bass as defined by an SBI value of 79. The
``without projects'' level of protection is the level of protection
that would have resulted in the absence of the state and Federal water
projects (the SWP and the CVP). EPA also conditioned its approval on
the State Board's commitment to develop additional criteria to protect
aquatic life and tidal wetlands in and surrounding the Suisun Marsh.
The State Board concurred with these [[Page 4666]] interpretations in
its letter to EPA dated November 21, 1980.
As fish and wildlife resources in the Bay/Delta continued to
decline, EPA on several occasions expressed its continuing concern to
the State Board about the need to develop standards that would
adequately protect these resources. Throughout the first and second
triennial reviews ending in 1981 and 1985, EPA urged the State Board to
review and revise the 1978 Delta Plan in accordance with EPA's 1980
approval letter. After its second triennial review, in a letter to EPA
dated June 23, 1986, the State Board acknowledged that the 1978 Delta
Plan standards were not adequate to protect the estuary's fishery
resources. It then outlined the hearing process it was planning for
revising the standards. In response, and as part of its consideration
of the State Board's second triennial review, EPA, on June 29, 1987,
sent a letter to the State Board stating that EPA could no longer
approve the striped bass survival standards (or the related provision
allowing relaxation of the spawning standard in drier years) because
these standards did not adequately protect the designated fish and
wildlife uses. EPA recognized, however, that the State Board had
initiated new hearings to revise the 1978 Delta Plan standards. EPA
therefore indicated that it would await the results of the new hearings
and approve or disapprove the revised standards after the State Board's
submission to EPA of a complete set of revised standards. Following the
first phase of the new hearings, the State Board in November 1988
issued a draft Plan that included revised salinity and flow standards
to protect the fisheries and other designated uses (SWRCB 1988). The
State Board subsequently withdrew that draft Plan, however, and issued
a revised workplan that served as the basis for the State Board's
present Water Quality Control Plan for Salinity for the San Francisco
Bay/Sacramento-San Joaquin Delta Estuary (1991 Bay/Delta Plan).
The 1991 Bay/Delta Plan, which the State Board submitted to EPA for
review on May 29, 1991, amended certain salinity criteria and adopted
new temperature and dissolved oxygen criteria for specified locations
in the estuary. The 1991 Bay/Delta Plan did not, however, revise the
earlier 1978 Delta Plan to address EPA's longstanding concerns about
adequate protection for the designated fish and wildlife uses of the
Bay/Delta.
On September 3, 1991, EPA approved in part and disapproved in part
the provisions of the 1991 Bay/Delta Plan. EPA's letter found that
``[t]he record * * * does not support the conclusion that the State has
adopted criteria sufficient to protect the designated uses'' of the
estuary. The designated uses at risk, as defined by the State Board,
include Estuarine Habitat, and also Cold and Warm Water Habitat, Fish
Migration, Fish Spawning, Ocean Commercial and Sport Fishing,
Preservation of Rare and Endangered Species, Shellfish Harvesting, and
Wildlife Habitat. In addition to its general finding that the 1991 Bay/
Delta Plan did not contain sufficient criteria to protect the
designated uses, EPA also disapproved the absence of salinity standards
to protect the Estuarine Habitat and other fish and wildlife uses in
the Suisun, San Pablo, and San Francisco Bays and Suisun Marsh, the
absence of scientifically supportable salinity standards (measured by
electrical conductivity) to protect the Fish Spawning uses of the lower
San Joaquin River, and the absence of scientifically supportable
temperature standards on the San Joaquin and Sacramento Rivers to
support the Fish Migration and Cold Fresh Water Habitat uses, including
the fall-run and winter-run chinook salmon.
In the summer of 1992, the State Board held hearings for the
purpose of establishing interim measures to protect the natural
resources in the Bay/Delta estuary. EPA participated in these
hearings--rather than proposing federal standards at that time--in the
hope that the hearings would result in state adoption of approvable
standards and preclude the need for a federal rulemaking. EPA submitted
its own recommendations to the State Board and joined with the National
Marine Fisheries Service (NMFS) and the U.S. Fish and Wildlife Service
(USFWS) in submitting an Interagency Statement of Principles. These
statements specifically recommended that the State Board adopt a
habitat and ecosystem-based approach to standards that would satisfy
CWA requirements and meet the State Board's goal of reversing the
decline of the estuary's fish and wildlife resources.
At the conclusion of these hearings, the State Board, on December
10, 1992, issued its recommended interim measures in Draft Water Rights
Decision D-1630 (hereinafter D-1630). After the close of the comment
period for D-1630, however, the State Board declined to adopt D-1630.
Accordingly, the State criteria EPA disapproved on September 3, 1991,
are still in effect. In response to the State Board's failure to revise
these criteria, EPA, pursuant to section 303 (c)(3) and (c)(4) of the
Act, published a Proposed Rule that would establish Federal water
quality criteria for the Bay/Delta which would in effect supersede and
supplement the disapproved State criteria for purposes of the CWA.
EPA's Proposed Rule also satisfied its obligations under a partial
settlement agreement approved and entered as an order in Golden Gate
Audubon Society et al. v. Browner, (E.D. Ca. Civ. No. 93-646 (LKK)).
EPA's Proposed Rule was one component of a coordinated initiative
by the several Federal agencies having regulatory or operational
responsibilities in the Bay/Delta. In early 1993, these four agencies--
EPA, USFWS, NMFS, and USBR--formed the Federal Environmental
Directorate (now known almost exclusively as ``Club FED'') for the
purpose of assuring that the Federal agencies worked in a coordinated
manner in taking actions under their respective statutory authorities
that would affect the estuary. The Federal initiative announced in
December 1993 included the EPA Proposed Rule, the USFWS proposal to
list the Sacramento splittail as a threatened species under the ESA,
the USFWS proposal for critical habitat for the threatened Delta smelt,
and the NMFS reclassification of the winter-run chinook salmon as
endangered. This initiative also coincided with the USBR's preliminary
water allocation forecast for CVP deliveries for the 1994 water year.
d. Post-Proposal Activities
Since the publication of the Proposed Rule, EPA has moved towards
final promulgation of protective criteria in an expeditious and open
manner. EPA held several public hearings throughout the state in late
February, 1994, to hear comments on the Proposed Rule. In addition, EPA
met with a number of interested parties to discuss the economic
analysis prepared in conjunction with the Proposed Rule. The purpose of
these meetings was to solicit recommendations as to how to improve the
analysis of potential economic impacts resulting from the State's
implementation of the Federal criteria.
EPA also participated in a series of scientific workshops arranged
and facilitated by California Urban Water Agencies (CUWA), the Bay
Institute, the Natural Heritage Institute, Save San Francisco Bay
Association, and the Environmental Defense Fund. These workshops were
designed to discuss the extensive scientific comments submitted by CUWA
on the criteria proposed in the Proposed Rule. Dr. Wim Kimmerer, the
reporter for these workshops, prepared written summaries of the
discussions on the Estuarine [[Page 4667]] Habitat criteria and the
Fish Migration Criteria (Kimmerer 1994b). As discussed above, the
summary of the workshops on the Fish Migration criteria and EPA's
alternative formulation of the Fish Migration criteria were made
available to the public in EPA's Notice of Availability published on
August 26, 1994, 59 FR 44095.
The Federal interagency cooperation effort begun before the
publication of the Proposed Rule has continued during the past year.
The most formal aspects of this cooperation effort have been the
consultations under Section 7 of the ESA between EPA and the USFWS and
NMFS on the potential effects of EPA's criteria on threatened and
endangered species and their critical habitat.\6\ EPA and the Services
began consulting informally in December 1991. Formal consultations were
initiated in August 1993. In recognition of the tentative nature of a
proposed rule, the Services deferred preparing a formal biological
opinion for the Proposed Rule and instead, on November 24, 1993,
submitted formal comments to EPA on the Proposed Rule. These formal
comments raised the major concerns of the respective Services about
potential effects of the proposed criteria on threatened and endangered
species. Since publication of the Proposed Rule, the Services have
worked closely with EPA to assure that the final rule complies with the
ESA. The Services have been actively involved in reviewing comments
received from the public, and participated in the CUWA scientific
workshops on EPA's Proposed Rule.
\6\As stated above, the species of concern include primarily the
winter-run chinook salmon (a listed endangered species under the
jurisdiction of NMFS) and the Delta smelt (a listed threatened
species under the jurisdiction of the USFWS). The USFWS has also
formally proposed that the Sacramento splittail be listed as
threatened.
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In early November 1994, after discussing the probable final
criteria with EPA, NMFS and USFWS concluded their reviews of the final
criteria and issued their respective final conclusions as to the
anticipated effects of the implementation of these criteria on
threatened and endangered species. The USFWS issued a ``no jeopardy''
biological opinion under Section 7 of the ESA, finding that
implementation of these criteria would not likely jeopardize the
continued existence of any listed species or result in adverse
modification of habitat deemed critical to the survival of listed
species. In recognition of the fact that the final EPA criteria may be
implemented only when the State Board adopts final implementation
plans, the USFWS biological opinion also called for the reinitiation of
consultations when the implementation plans are finalized by the State
Board so that any possible problems for endangered or threatened
species caused by implementing the criteria can be addressed.
NMFS concluded its review by making a finding that implementation
of these criteria would not adversely affect the threatened and
endangered species or result in adverse modification of critical
habitat of those species (anadromous fishes) under its jurisdiction.
The NMFS findings also called for reinitiation of consultation when
implementation plans are developed by the State Board, so that any
possible problems for threatened or endangered species caused by
implementing the criteria can be addressed.
In addition to the formal ESA consultation process, the four Club
Fed agencies have again coordinated several of their regulatory and
operational duties and are announcing two Federal actions
simultaneously. In addition to EPA's final promulgation of water
quality criteria under the CWA, the USFWS is making it's final
designation of critical habitat for the Delta smelt under the ESA.
These coordinated Federal actions serve as the underlying basis for the
long-term solution to fish and wildlife protection in the Bay/Delta
estuary.
Finally, in an effort to facilitate the long-term resolution of
Bay/Delta issues, the Club Fed agencies and their counterpart agencies
in the State of California executed, as of July 1994, a Framework
Agreement laying out the Federal and State intentions as to how these
agencies would work together cooperatively on a range of issues in the
estuary. One key element of this Framework Agreement was EPA's
agreement to sign a final rule regarding these water quality criteria
by the end of 1994. At the same time, the State Board agreed to prepare
a draft revision to its water quality plan by the end of 1994, and to
finalize that plan in early 1995. The Framework Agreement envisions
that, if EPA finds that the revised State plan submitted to EPA meets
the requirements of the CWA, EPA will initiate action to withdraw this
rule.
Consistent with its commitment in the Framework Agreement, the
State Board conducted a series of workshops on Bay/Delta issues
throughout the spring, summer and fall of 1994. EPA participated in
these workshops, and has continued to work with the State Board to
assure that the revisions adopted by the State Board will meet the
requirements of the CWA. It is EPA's hope that the cooperative process
outlined in the Framework Agreement will lead to approvable state
standards for protecting the designated uses in the Bay/Delta estuary.
EPA is aware of efforts by urban and agricultural users, in
cooperation with environmental groups, to identify alternative
standards that may meet the requirements of the CWA. EPA encourages
affected parties to continue to work with EPA and the State to develop
proposals that meet the requirements of the CWA. EPA would welcome the
adoption by the State of a revised plan based in whole or in part on
such private proposals provided that it complies with the requirements
of the CWA.
B. Statutory and Regulatory Background
Section 303(c) of the Act requires that state water quality
standards ``* * * be such as to protect the public health or welfare,
enhance the quality of water and serve the purposes of this [Act]. Such
standards shall be established taking into consideration their use and
value for propagation of fish and wildlife, recreational purposes, and
agricultural, industrial, and other purposes. * * *'' Key concerns of
this statutory provision are the enhancement of water quality for the
protection of the propagation of fish and other aquatic life. The
ultimate purpose of water quality standards, as with the other
provisions of the CWA, is ``to restore and maintain the chemical,
physical, and biological integrity of the Nation's waters.'' CWA
section 101(a).
Under section 303(c) of the Act, a water quality standard for a
specific waterbody consists of two components: designated uses for
which a waterbody is to be protected (such as recreation in and on the
water, protection and propagation of fish and wildlife, or agricultural
uses) and the water quality criteria which support those designated
uses.\7\
\7\As discussed below, a state's water quality standards must
also contain an antidegradation policy.
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The Act gives primary responsibility for the adoption of water
quality standards to the states. After adopting its initial water
quality standards, a state is required, no less than every three years,
to review those standards, and, if necessary, modify them. Under
section 303(c)(1) of the Act, if a state revises or adopts a new
standard, it must submit such a standard to EPA for approval or
disapproval. [[Page 4668]]
EPA's Water Quality Standards regulations at 40 CFR part 131
specify the requirements for designated uses. ``Designated Uses'' are
those uses specified in water quality standards for each water body or
segment whether or not they are being attained. 40 CFR 131.3(f).
Examples of designated uses are listed in section 303(c)(2)(A) of the
CWA. They include: public water supplies, protection and propagation of
fish, shellfish, and wildlife, recreation, agricultural and industrial,
and navigation. Other uses have been adopted as well (e.g. aquifer
protection, coral reef preservation).
Under certain circumstances, States may remove a designated use
which is not an existing use. 40 CFR 131.10(g). ``Existing Uses'' are
those uses actually attained in the water body on or after November 28,
1975, whether or not they are included in the water quality standards.
40 CFR 131.3(f). Generally, existing uses, whether or not they are
``designated uses,'' may not be removed. 40 CFR 131.3(g) and (h). A
state must conduct a ``use attainability analysis'' as defined in 40
CFR 131.3(g) whenever (1) the State designates uses that do not include
the uses specified in section 101(a)(2) of the CWA, or (2) the State
wishes to remove a designated use that is specified in section
101(a)(2) of the CWA or to adopt subcategories of uses which require
less stringent criteria. 40 CFR 131.3(j). The state may take economics
into account when it designates uses, as, for example, in a use
attainability analysis. 40 CFR 131.3(g)(6).
EPA's Water Quality Standards regulations at 40 CFR part 131
specify the requirements for water quality criteria.
States must adopt those water quality criteria that protect the
designated use. Such criteria must be based on sound scientific
rationale and must contain sufficient parameters or constituents to
protect the designated use. For waters with multiple use
designations, the criteria shall support the most sensitive use. 40
CFR 131.11(a).
Thus, once designated uses are established, the water quality criteria
are based on what is necessary scientifically to protect the most
sensitive designated use.
In addition, a state's criteria must be consistent with the state's
antidegradation policy. The federal regulations provide that, at a
minimum, the state must have an antidegradation policy that maintains
``[e]xisting instream water uses [those existing in the waterbody at
any time on or after November 28, 1975] and the level of water quality
necessary to protect the existing uses. * * *'' 40 CFR 131.12(a)(1).
In order to approve a state's water quality criteria, EPA must
determine that the state has adopted ``water quality criteria [that
are] sufficient to protect the designated uses.'' 40 CFR 131.6(c).
Section 303(c)(4) of the Act provides that the Administrator shall
promptly prepare and publish proposed regulations establishing a new or
revised standard in either of two situations: first, when the
Administrator has disapproved a state standard under section 303(c)(3)
and the state has not taken corrective action within 90 days; and,
second, in any case where the Administrator determines that a revised
or new standard is necessary to meet the requirements of the Act. Once
promulgated, the federal regulations are applicable to the state's
waters, and, if they are more stringent, have the effect of supplanting
and supplementing the state's standards for all purposes under the CWA.
However, it is EPA's longstanding policy that the federal water quality
standards will be withdrawn if a state adopts and submits standards
that in the Agency's judgment meet the requirements of the Act.
The chronology of State and EPA actions under the CWA in the Bay/
Delta estuary over the past two decades were described in more detail
in the preamble to the Proposed Rule, and in paragraph A.1.c. herein.
Briefly stated, the State Board's adoption of the 1978 Delta Plan, and
of the revised Bay/Delta Plan in 1991, were intended to meet the
State's obligations to establish water quality standards under the CWA.
Pursuant to its mandate under section 303(c)(3) of the Act, on
September 3, 1991, EPA disapproved several of the criteria contained in
the State Board's plan. EPA's letter found that ``[t]he record * * *
does not support the conclusion that the State has adopted criteria
sufficient to protect the designated uses'' of the estuary. The
designated uses at risk, as defined by the State Board, include
Estuarine Habitat, and also Cold and Warm Water Habitat, Fish
Migration, Fish Spawning, Ocean Commercial and Sport Fishing,
Preservation of Rare and Endangered Species, Shellfish Harvesting, and
Wildlife Habitat. In addition to its general finding that the 1991 Bay/
Delta Plan did not contain sufficient criteria to protect the
designated uses, EPA also disapproved the absence of salinity criteria
to protect fish and wildlife uses in the Suisun, San Pablo, and San
Francisco Bays and Suisun Marsh, the absence of scientifically
supportable salinity criteria (measured by electrical conductivity) to
protect the Fish Spawning uses of the lower San Joaquin River, and the
absence of scientifically supportable temperature standards on the San
Joaquin and Sacramento Rivers to protect the Fish Migration and Cold
Fresh Water Habitat Uses.
For the reasons outlined herein, in the Proposed Rule, and in EPA's
letter of September 3, 1991, the Agency finds that the water quality
criteria adopted by the State fail to protect the designated uses and
that the criteria below meet the requirements of the Act. Accordingly,
pursuant to sections 303(c)(3) and 303(c)(4) of the Act, the
Administrator is promulgating the following water quality criteria
applicable to the Bay/Delta's waters.
C. Description of the Final Rule and Changes From Proposal
1. Estuarine Habitat Criteria
a. Overview
(1) Importance of the Estuarine Habitat Designated Use. The State's
1991 Bay/Delta Plan included ``Estuarine Habitat'' as a designated use
for the Bay/Delta estuary. This Estuarine Habitat designated use is
intended to provide ``an essential and unique habitat that serves to
acclimate anadromous fishes (salmon, striped bass) migrating into fresh
or marine conditions. This habitat also provides for the propagation
and sustenance of a variety of fish and shellfish, numerous waterfowl
and shore birds, and marine mammals.'' See Water Quality Control Plan,
San Francisco Bay Basin [2], December 1986, at II-4.
EPA considers protection of the Estuarine Habitat designated use to
be important for a number of important reasons. As described in detail
in the Preamble to the Proposed Rule, conditions in the estuary are of
critical importance because the estuary's particular characteristics
provide a unique food source, spawning habitat or nursery habitat for a
whole range of aquatic and aquatic-dependent species. The Estuarine
Habitat designated use protects this vital ecosystem, an ecosystem that
has a crucial role in restoring and protecting the fish and wildlife
populations of the Bay/Delta. EPA and the other Federal agencies are
committed to multispecies or ecosystem protection approaches, rather
than focusing on the peculiar needs of individual species. In addition,
the resource values benefitting from the protection of the Estuarine
Habitat use include resources described in other state-designated uses,
including Ocean Commercial and Sport Fishing, Preservation of Rare and
Endangered Species, Fish Migration, and Wildlife
[[Page 4669]] Habitat.\8\ Indeed, many of the resources targeted for
protection by these related uses would not be fully protected without
adequate protection of the Estuarine Habitat designated use. In
developing criteria protective of the Estuarine Habitat use, EPA has
been mindful of the overlapping designated uses and of the range of
natural resources affected by the broad Estuarine Habitat.
\8\As described by the State Board, the Ocean Commercial and
Sport Fishing designated use protects the ``commercial fishing and
collection of various types of fish and shellfish, including those
taken for bait purposes, and sport fishing in ocean, bays, estuaries
and similar non-freshwater areas.'' The Preservation of Rare and
Endangered Species use ``[p]rovides an aquatic habitat necessary, at
least in part, for the survival of certain species established as
being rare and endangered species.'' As described below, the Fish
Migration use ``[p]rovides a migration route and temporary aquatic
environment for anadromous or other fish species.'' Finally, the
Wildlife Habitat ``[p]rovides a water supply and vegetative habitat
for the maintenance of wildlife.''
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BILLING CODE 6560-50-P
[[Page 4670]]
[GRAPHIC][TIFF OMITTED]TR24JA95.000
BILLING CODE 6560-50-C [[Page 4671]]
(2) Proposed Criteria. As stated in the Proposed Rule, the
Estuarine Habitat criteria consisted of three interrelated components:
(i) A salinity requirement of 2 parts per thousand (2 ppt);
(ii) Maintained at one or more of three monitoring locations in the
Suisun Bay;
(iii) For a specified number of days during the critical spring
months.
These criteria were designed to reflect the conditions in the estuary
at a time when it attained protection of the designated Estuarine
Habitat use.
As a preliminary matter, EPA determined the ``reference period,''
the historical time period during which the salinity regime in the
estuary was sufficient to protect the designated uses. To determine the
reference period, EPA was guided by the Interagency Statement of
Principles signed by EPA, USFWS and NMFS, which called for estuarine
conditions similar to the late 1960's to early 1970's as necessary to
protect the Estuarine Habitat. However, the decade from 1965 to 1974
did not include water years types from each of the five water year type
categories.\9\ Therefore, in order to estimate those conditions over
the entire range of possible hydrological conditions that may occur in
the future, EPA used data from the years 1940 to 1975 to represent the
conditions in the reference period of the late 1960's to early 1970's,
and used this larger set of historical data to determine the minimum
number of days of compliance.
\9\``Water year'' type categories in California refer to
precipitation patterns for the year. The standard water year
categories are wet, above normal, below normal, dry, and critically
dry years.
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As explained in more detail below and in the preamble to the
Proposed Rule, EPA then focused on the salinity regime in the estuary
to develop criteria that protect the Estuarine Habitat. Salinity was
selected for several reasons: it is closely associated with the
abundance and distribution of species at all trophic levels, it can be
measured accurately and easily, and it integrates a number of important
estuarine properties and processes.
Salinity conditions in the estuary vary dramatically from month to
month and year to year, primarily in response to natural factors such
as precipitation and snowmelt upstream, and to man-made factors such as
reservoir operations, upstream diversions and export rates. EPA
concluded that maintaining salinity conditions reflecting the natural
hydrology in the Bay/Delta during the reference period would provide
estuarine habitat conditions that protect the fish and wildlife
resources dependent on that habitat. In other words, because
precipitation varies naturally from year to year and within each year,
salinity conditions reflecting this natural variability at a time
period when the Bay/Delta attained its designated uses would protect
the natural resources dependent upon estuarine habitat. While it may
seem counterintuitive to provide less fresh water to the estuary in a
dry year, and more water in a wet year, the natural resources in the
Bay/Delta ecosystem have adapted to the cycle of both within-year
hydrological fluctuations and substantial year-to-year fluctuations in
hydrology. The intent of the proposed criteria was to restore a pattern
and magnitude of those hydrological fluctuations that reflected the
historical period during which the designated uses were fully
protected.
To provide these conditions, EPA proposed maintaining the low
salinity\10\ 2 ppt isohaline (an isohaline is simply a line joining all
points of equal salinity) in Suisun Bay during the critical wet season
months of February to June. This particular time period is important
because many different species use the low salinity habitat in the
spring for spawning, as nursery habitat, for transportation through the
Delta, or for a combination of these three purposes. To take account of
the variation in natural hydrological conditions, EPA proposed criteria
that varied according to the water year type. In all water years, the 2
ppt salinity criteria would be met at the furthest upstream monitoring
site (the confluence of the Sacramento and San Joaquin Rivers at the
upstream end of Suisun Bay). In wetter years, the 2 ppt salinity
criteria would also be met at one or both of two downstream monitoring
sites (Chipps Island and Roe Island, in the middle and downstream end
of Suisun Bay, respectively).
\10\Low salinity in the 2 ppt range is being used to describe
salinity conditions in the ``mixing zone'' between freshwater coming
downstream and marine water moving inland from the ocean in response
to tidal influences and fluctuations in freshwater outflow. This
mixing zone generally contains low surface salinity of 1 to 6 ppt,
whereas ocean salinity is over 30 ppt and freshwater salinity is
generally less than 1 ppt (Arthur and Ball 1979).
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The proposal was stated as requiring attainment of the 2 ppt
salinity criteria at or below one of the three monitoring sites for a
specified number of days during the February to June period, depending
on the water year type. For example, under the Proposed Rule, in a
``below normal'' water year, the 2 ppt isohaline would have been
required at or downstream of Chipps Island for a total of 119 days
during the February to June period. This ``number of days'' approach
allowed the criteria to be responsive and replicative of the varying
natural hydrology during February to June. That is, if February or
March were particularly wet, the criteria's ``number of days'' could be
met at that time using those natural storm flows, rather than requiring
reservoir releases later in the February to June period.
Finally, again in an attempt to match the criteria with the natural
hydrology, the Proposed Criteria included a ``trigger'' for compliance
with the farthest downstream monitoring site (Roe Island). Compliance
at that site would not be required unless and until the 2 ppt isohaline
had been pushed that far downstream through natural storm events.
(3) Final Criteria. The Estuarine Habitat criteria in the final
rule have been revised to address many of the technical issues raised
in the public comments. The fundamental structure of the Estuarine
Habitat criteria is unchanged: The criteria require maintenance of the
2 ppt\11\ isohaline at or downstream of one of three monitoring sites
in Suisun Bay during a specified portion of the February through June
period. The final criteria continue to require a 2 ppt salinity value
at the Confluence of the Sacramento and San Joaquin rivers each day
between February through June in all years. The 2 ppt salinity value is
to be met at Chipps Island for a specified number of days, depending on
the amount of precipitation. The greater the precipitation, the higher
the number of days the criteria must be attained. The 2 ppt salinity
value must be met at Roe Island only if it is triggered by
precipitation sufficient to push the 2 ppt salinity value downstream to
Roe Island during the last half of the previous month. Once triggered,
the 2 ppt salinity value is to be met at Roe Island for a specified
number of days, depending on precipitation.
\11\The Proposed Rule stated the criteria as a requirement for 2
ppt salinity. As discussed more fully below, in order to state the
requirement more precisely, the final rule language will define the
criteria in terms of micromhos per centimeter specific conductance
at 25 deg.C instead of parts per thousand salinity. Accordingly,
the final rule will state the criteria value as ``2640 micromhos/
cm,'' which is equivalent to 2 ppt salinity. Although EPA is
restating the actual rule language in the more precise specific
conductance language, it will continue to refer to this criteria
value as 2 ppt in this discussion of the final rule.
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The changes to the final criteria are primarily refinements to how
the rule determines the number of days the salinity standard must be
met at Chipps and Roe Islands. The primary revisions include:
(i) Shift from water year categories to a ``sliding scale''. Rather
than basing the number of days on data reflecting average salinity for
each of the five water year types, EPA is basing the number of days on
a ``sliding scale'' or ``smooth function'' that more precisely states
the correlation between precipitation and the number of days of the 2
ppt value. For example, whereas the previous approach would require the
same number of days of the 2 ppt value for all ``above normal'' years,
the sliding scale requires fewer number of days for a dry ``above
normal'' year than for a wet ``above normal'' year. In other words,
rather than stating the criteria as five discrete points representing
water year types, the sliding scale uses all the data underlying those
five points to construct a continuous function or line reflecting
salinity as a function of flow. The sliding scale is a more realistic
description of the relationship between salinity and flow as it existed
at the time during which the estuary attained its designated uses.
(ii) Shift from yearly hydrology to monthly hydrology. Instead of
basing the number of compliance days at Chipps and Roe Islands on the
expected hydrological conditions for the entire year, the final
criteria base the current month's requirements only on the previous
month's hydrological conditions. This change requires that these
criteria specify a ``sliding scale'' for each month, but allows a much
more accurate reflection of variations in natural hydrology.
(iii) Revising the data used to reflect more accurately conditions
in the estuary during the reference period. As explained above, the
reference period is the historical time period when the estuary
attained its designated uses. In the Proposed Rule, EPA used the late
1960's to early 1970's as the reference period because the available
information about the fish and wildlife resources in the Bay/Delta
suggests that this time period encompasses the most recent time period
during which the designated uses were attained. To describe
hydrological and salinity conditions in this late 1960's to early
1970's reference period, the Proposed Rule used data from 1940 to 1975.
This longer period was used because the actual conditions in the late
1960's to early 1970's did not provide representative samples of the
possible broad range of hydrological conditions in the estuary. The
Proposed Rule suggested that the period 1940-1975 could be considered
representative of the late 1960's to early 1970's because the longer
period was one of fairly consistent hydrological conditions bracketed
by the completion of Shasta Dam on the Sacramento in the early 1940's
and by the severe drought of the mid-1970's.
EPA received much comment on the approach in the Proposed Rule,
with some commenters arguing convincingly that the 1940 to 1975 was in
fact not one of consistent hydrological conditions, since the ``level
of development''--the change in the facilities used for water diversion
and storage--changed over time during this period due to additional
construction activities at the state, federal, and local levels. EPA
agrees with these comments and has reevaluated the historical data to
account for the effects of the level of development on the salinity
regime in Suisun Bay. As discussed below, EPA has determined that it is
appropriate to use the level of development--and corresponding salinity
regime--represented by calendar year 1968 as a surrogate for the late
1960's to early 1970's reference period when the estuary attained its
designated uses.
(iv) Alternative measures of attainment. Under the CWA, the State
Board has the responsibility for developing an implementation plan,
including the methodology for measuring attainment. Based on the
comments received as discussed below, EPA believes that attainment
could be measured at the Roe Island and Chipps Island monitoring sites
by any of (1) the daily salinity value, (2) the 14-day average
salinity, or (3) the ``flow equivalence'' of the salinity value, as
predicted in the recent Contra Costa Water District (CCWD) model
described below. For reasons that are peculiar to that model,
attainment at the Confluence monitoring site could be measured by
either of the first two of these approaches only.
b. Detailed Discussion
(1) Proposed Estuarine Habitat Criteria
The Estuarine Habitat criteria included in the Proposed Rule
specified the location and number of days that the 2 ppt salinity value
would need to be met to protect the designated use. EPA's proposed
criteria are shown in Table 1. They consisted of 2 ppt salinity
criteria12 to be attained for a specified number of days at Roe
Island, Chipps Island, and at the Sacramento/San Joaquin River
confluence during the period of February through June. The Proposed
Rule provided that the 2 ppt salinity value must be met at the
Sacramento/San Joaquin River confluence monitoring station for the
entire 150 day period from February through June. The number of days of
compliance with the 2 ppt value at Chipps and Roe Islands were based on
the late 1960's to early 1970's ``reference period'' representing a
time in which the conditions in the estuary were adequate to protect
the designated uses. To represent this reference period, the criteria
replicated the average number of days in each of the five water year
types during which the 2 ppt salinity value occurred at or downstream
from each of these locations during the historical period 1940-1975.
Because no critically dry years occurred in the period from 1940 to
1975, the required number of days for critically dry years was based on
an extrapolation of the data. In addition, in a number of years in the
1940-1975 period, data existed for flow conditions in the estuary but
not for salinity. For these years, the Kimmerer-Monismith model (SFEP
1993) was used to estimate the salinity regime based on the existing
flow data. [[Page 4672]]
\12\EPA's proposed Estuarine Habitat criteria were stated as a
certain number of days when the average daily near-bottom salinity
at each of three locations in the estuary is less than 2 parts per
thousand. This salinity is approximately equivalent to electrical
conductivity less than 2.640 mmhos/cm EC when corrected to a
temperature of 25 deg.C.
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The proposed criteria were to be measured using a 14-day moving
average.13 The use of a 14-day moving average allowed the mean
location to be achieved despite the varying strength of tidal currents
during the lunar cycle, because any 14 day period would include the
full range of spring and neap tidal conditions.14
\13\A 14 day moving average would compute the salinity for a
given day by taking the overall average of daily averages of
salinity values for the measurement day and each of the previous 13
days. At the monitoring sites used in the Estuarine Habitat
criteria, salinity is generally measured at least hourly, thereby
facilitating computation of daily averages.
\14\Spring and neap tides refer to the times during the 28 day
lunar cycle when tides are strongest and weakest, respectively.
[[Page 4673]]
Table 1.--Proposed 2 ppt Estuarine Habitat Criteria\1\
------------------------------------------------------------------------
Chipps Island [km Confluence
Year type Roe Island [km 64] 74] [km 81]
------------------------------------------------------------------------
Wet............... 133 days.......... 148 days......... 150 days.
Above normal...... 105 days.......... 144 days......... 150 days.
Below normal...... 78 days........... 119 days......... 150 days.
Dry............... 33 days........... 116 days......... 150 days.
Critically dry.... 0 days............ 90 days.......... 150 days.
------------------------------------------------------------------------
\1\Numbers indicate the required number of days (based on a 14-day
moving average) at or downstream from each location for the 5-month
period from February through June. The water year classifications are
identical to those included in the 1991 Bay/Delta Plan for the
Sacramento River Basin. Roe Island salinity shall be measured at the
salinity measuring station maintained by the USBR at Port Chicago (km
64). Chipps Island salinity shall be measured at the Mallard Slough
station, and salinity at the Confluence shall be measured at the
Collinsville station, both of which are maintained by the California
Department of Water Resources. The Roe Island number represents the
maximum number of days of compliance, based on the adjustment
described in the text.
As explained in more detail in the Proposed Rule, the proposed
Estuarine Habitat criteria also included a ``trigger'' that limited the
applicability of the Roe Island criteria to wetter years. This trigger
provided that the Roe Island criteria would not apply in a particular
year unless and until the average daily salinity at Roe Island attained
the 2 ppt level through natural uncontrolled flows. If that occurred,
the 2 ppt salinity value would have to be met at Roe Island for the
number of days specified in Table 1 (or the number of days left in the
February to June period, if that number was less). In effect, this
``trigger'' provided that the additional water needed to move the 2 ppt
isohaline downstream to Roe Island would come from natural storms
rather than from reservoir releases or export restrictions. This
approach helped the criteria reproduce the natural variability in
timing and quantity of runoff that existed during the reference period.
In the Proposed Rule, EPA requested public comment on a number of
issues, including the desirability of stating the criteria as a
``sliding scale'' rather than by water year categories, the appropriate
compliance measurement period, and the appropriate reference period for
criteria target levels. EPA has incorporated many of the comments
received on these and other issues in its revisions to the Proposed
Rule.
(2) Technical Changes to the Estuarine Habitat Criteria
The fundamental structure of the Estuarine Habitat criteria in the
final rule is unchanged from the Proposed Rule: The criteria require
maintenance of the 2 ppt isohaline at or downstream of one of three
monitoring sites in Suisun Bay during a specified portion of the
February through June period. The final criteria continue to require a
2 ppt salinity value at the Confluence of the Sacramento and San
Joaquin rivers each day between February through June in all years.
Virtually all of the changes to the final Estuarine Habitat
criteria involve refinements for determining the number of days the
salinity standard must be met at Chipps and Roe Islands. In general,
these changes either make certain measurements more accurate or provide
a closer approximation of the natural hydrological cycles. The changes,
which are highly technical, can be grouped into four broad categories:
(i) underlying computational revisions, (ii) using a sliding scale,
(iii) using monthly rather than annual compliance, and (iv) alternative
measurement of attainment of the criteria. These changes to the final
rule are reflected in the final criteria at 40 CFR 131.37(a)(1).
(i) Underlying Computational Revisions.
The first group of changes in the final criteria are slight
refinements to the methodology of some of the computations used in the
rule. These include:
(I) Updated model correlating salinity and flows. As described
above, the Proposed Rule used data from the historical period 1940 to
1975 to approximate conditions in the targeted late 1960's to early
1970's reference period. For years during that historical period when
actual salinity data was unavailable, the Proposed Rule used the
Kimmerer-Monismith model to estimate salinity conditions based on the
available flow data. This earlier model, which was used by the San
Francisco Estuary Project (SFEP) (SFEP 1993), was considered at that
time to be the most accurate available for this purpose. Since the
Proposed Rule was published, a revised model correlating salinity and
flow has been developed by the CCWD (Denton, R.A. 1993, and Denton,
R.A. 1994). EPA concluded, and the participants at the CUWA scientific
workshops generally agreed (Kimmerer 1994b), that the CCWD model is a
more appropriate model to use in developing the Estuarine Habitat
criteria.15 The final rule will use this new CCWD model to
estimate the number of days that salinities have been less than 2 ppt
historically at each of the compliance monitoring stations.
\15\The CCWD model developed by Denton and Sullivan models
salinity at a particular location, whereas the Kimmerer-Monismith
model models the location of a particular salinity. Thus, the
Kimmerer-Monismith model can predict whether the 2 ppt salinity
value is upstream or downstream of a given location whereas the CCWD
model can predict if the salinity at the same point is greater or
lesser than 2 ppt. The CCWD model is more accurate because it
predicts salinity based not only on flow (as in the Kimmerer-
Monismith model) but also based on the location being modeled. For
example, the relationship between flow and salinity is slightly
different at Roe Island than at the Confluence, and only the CCWD
model reflects that difference in the relationship.
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The earlier model used for the Proposed Rule measured salinity one
meter above the bottom. The new CCWD model measures salinity measured
at the surface. There is substantial evidence that at salinities near 2
ppt there is little variability in stratification so that bottom
salinities are accurately predicted from surface salinities (CCWD 1994;
Monismith 1993). Therefore, bottom salinities of 2 ppt as modeled by
the Kimmerer-Monismith model correspond to surface conductivities
described, as discussed below, in terms of electroconductivity of 2.640
mmhos/cm EC in the CCWD model.
(II) Use of entire basin unimpaired flow. In calculating the
applicable Estuarine Habitat criteria value, the Proposed Rule measured
flow by reference to the Sacramento Basin Water Year Type
classification. EPA did this primarily to simplify calculations and to
reflect the dominant role of Sacramento River flows in the Bay/Delta
estuary.16 Nevertheless, as commenters noted, in some
circumstances the omission of the San Joaquin River basin flows from
the calculation could significantly overstate [[Page 4674]] or
understate the actual hydrological conditions in the estuary because
precipitation patterns in the two river basins are not identical.
Further, one of the reasons EPA chose the three locations for
compliance (all at or downstream of the confluence of the Sacramento
and San Joaquin Rivers) was to give the State Board maximum flexibility
in determining the source of flows to meet the Estuarine Habitat
criteria. To reflect the importance of the San Joaquin River basin, the
final criteria have been revised to measure unimpaired flow by
reference to both the Sacramento River basin (Sacramento, Feather,
Yuba, and American rivers) and the San Joaquin River basin (Stanislaus,
Tuolumne, Merced, and San Joaquin rivers). EPA believes that the
Sacramento/San Joaquin Unimpaired Flow Index described by CUWA is the
best statement of how this unimpaired flow should be computed, and will
generally refer to this index as the ``8-River Index.''17
\16\The Sacramento River basin usually accounts for about 80% of
net Delta outflow, with the remainder coming primarily from the San
Joaquin River basin.
\17\As stated on page 3 of Appendix 1 to the California Urban
Water Agencies ``Recommendations to the State Water Resources
Control Board for a Coordinated Estuarine Protection Program for the
San Francisco Bay-Sacramento and San Joaquin River Delta Estuary''
dated August 25, 1994, the Sacramento/San Joaquin Unimpaired Flow
Index ``shall be computed as the sum of flows at the following
stations:
1. Sacramento River at Band Bridge, near Red Bluff
2. Feather River, total inflow to Oroville Reservoir
3. Yuba River at Smartville
4. American River, total inflow to Folsom Reservoir
5. Stanislaus River, total inflow to New Melones Reservoir
6. Tuolumne River, total inflow to Don Pedro Reservoir
7. Merced River, total inflow to Exchequer Reservoir
8. San Joaquin River, total inflow to Millerton Lake.''
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(III) ``Parts per thousand'' versus ``electroconductivity''. The
Proposed Rule stated the criteria as a requirement for 2 ppt salinity
at the three compliance stations for varying numbers of days. In order
to state the requirement more precisely, the final rule language will
define the criteria in terms of millimhos per centimeter
electroconductivity or ``mmhos/cm EC'' instead of parts per thousand
salinity. This change is being made to conform the final rule to the
more traditional methodology for measuring fresh water salinity.
Accordingly, the final rule will state the criteria value as ``2.640
mmhos/cm EC,'' which is equivalent to 2 ppt salinity.
Although EPA is restating the actual rule language in the more
precise electroconductivity language, it will continue to refer to this
criteria value as 2 ppt in this discussion of the final rule. To do
otherwise would unnecessarily confuse the interested scientific and
policy community, which for a number of years has been using the 2 ppt
language in its discussion of estuarine habitat criteria.
These revisions to the underlying computational methodology apply
to the Estuarine Habitat at all three monitoring sites (the Confluence,
Chipps, and Roe Islands). The remaining revisions to the final criteria
pertain primarily to the methodology used in defining the number of
days of compliance to be met at Chipps and Roe Islands.
(ii) Using a Sliding Scale.
In the final Estuarine Habitat criteria, EPA is restating the
number of days that the 2 ppt salinity value must be met as a sliding
scale correlating the number of days of compliance with unimpaired
flow. The sliding scale approach has also been called the ``continuous
function'' or ``smooth function'' approach. This approach replaces the
Proposed Rule's statement of the criteria as a single fixed number of
days of compliance for each of the five water year categories. The
previous approach did not account for the substantial differences in
hydrological conditions within water year types. For example, an
``above normal'' water year type could range from a wet ``above
normal'' year to a dry ``above normal'' year. Given the extreme
variation of hydrological conditions in the Bay/Delta, these variations
within each of the five standard water years types are substantial, and
should be factored into the calculation of the number of days of
compliance with the 2 ppt salinity criteria.
The sliding scale approach addresses this problem by transforming
the average salinity values for the five discrete water year categories
into a more precise equation (graphically, a single line or curve)
correlating the number of days of compliance with the specific observed
hydrological conditions. This sliding scale approach would result in
the same average number of days of compliance for each year type, and
therefore represents the same level of protection for the Estuarine
Habitat use as the Proposed Rule. The new approach, however, more
accurately reflects differences within water year categories, thereby
allowing a more accurate reflection of the natural hydrological cycles
representative of the reference period necessary for protection of the
use.
In addition, while the sliding scale approach equally represents
the conditions under which the estuary attains its designated uses, the
sliding scale results in lower water costs and, for operational
reasons, may actually enhance protection of the uses. Testimony at
recent State Board hearings criticized the use of water year type
categories. Because water year types can change as the year progresses,
criteria based on the historical mean for each water year type can
cause major changes in project operations and habitat conditions if a
given year shifts from one water year type to another over the course
of the winter months. For example, a later season storm could cause the
water year type to be reclassified from the below normal category to
the above normal category. This shift would increase the number of days
the criteria must be met at one of the monitoring sites. Such large and
sudden changes are inefficient for water resource management and may
harm aquatic resources by dewatering or washing away newly spawned
eggs. Incorporating a sliding scale definition of the criteria would
likely ease the actual operational procedures necessary to meet the
criteria and would avoid the relatively sudden, large scale changes in
operations that might come from a sudden shift in the determination of
year type as spring progresses.
The comments EPA received on the Proposed Rule were generally
supportive of this change in approach (CUWA 1994a, California DWR 1994,
NHI 1994, and Kimmerer 1994a). Both written comments and the
discussions at the CUWA scientific workshops offered several
suggestions as to how the sliding scale function should be formulated.
There are two major components to the sliding scale approach.
First, the shape of the scale must be determined. Second, the actual
scaled values must be determined.
(I) Defining the sliding scale. There are a number of possible
mathematical definitions of a sliding scale, including (a) a straight
line, (b) a quadratic equation, or (c) a logistic equation.18
\18\The standard forms of these types of equations are (a) a
straight line (y=a+b*x), (b) a quadratic equation (y=a+b*x+c*x2) or
(c) a logistic equation (y=1/(1+e3(a+b*x)).
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In the Proposed Rule, EPA suggested that a quadratic equation could
be used to define the sliding scale. After reviewing the public
comments, EPA has concluded that the Estuarine Habitat criteria should
be stated as a logistic equation defining the sliding scale. Dr. Wim
Kimmerer, in his comments on the Proposed Rule (Kimmerer 1994a), noted
that the logistic model is ``appropriate [[Page 4675]] for a
relationship between a dichotomous variable (i.e. compliance or no
compliance) and a continuous variable.'' A logistic model cannot
require fewer than 0 or more than the number of days available in the
month, whereas linear equations (such as one included in written
comments of CCWD (CCWD 1994) or quadratic equations (such as the one
EPA suggested in the Proposed Rule) can result in unrealistic
extrapolations (e.g., resulting in the criteria having to be met less
than zero days or more than the number of possible days each
month).19
\19\While uncommon in some fields, the logistic equation is the
basis of many ecological models, especially for population dynamics
and epidemiology. In these ecological applications, the logistic
model is useful because of the nature of the dichotomous variables
(such as how many individuals are alive or dead in population
dynamics, or how many individuals are infected or healthy in
epidemiological studies). In each case, the dichotomous variables
are arrayed along time as the continuous variable. In both cases,
also, the function is constrained between 0 and the total population
size, which is biologically realistic. EPA is using the logistic
equation to model the number of days of attainment of the 2 ppt
value (the dichotomous variable) against unimpaired flow (as the
continuous variable). The logistic model also provides that no less
than 0 and no more than the total number of days in the month can be
required for attainment.
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Kimmerer suggested a sliding scale based on logistic equations that
stated the percentage number of days of compliance during the February
to June period as a function of the unimpaired flow for those five
months. An example of graphic representations of these equations for
Roe Island is shown in Figure 1. EPA has adopted this basic approach;
however, as discussed below, EPA has revised the logistic equations to
reflect monthly computations of compliance.
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(II) Selecting sliding scale values: the reference period that
would reflect protection of the designated uses. Having concluded that
the logistic equation is the best form of sliding scale for the
Estuarine Habitat criteria, EPA still needed to determine the
appropriate reference period reflected in that logistic equation.
In the Proposed Rule, EPA chose as the reference period the late
1960's to early 1970's. Available information suggested that during
this period the estuarine conditions were able to support the
designated uses. To describe the conditions in this late 1960's to
early 1970's reference period, the Proposed Rule used hydrological and
salinity data from 1940 to 1975. This longer period was used because
the actual conditions in the late 1960's to early 1970's did not
provide representative samples of the possible broad range of
precipitation conditions in the estuary.20 The Proposed Rule
suggested that the period 1940-1975 could be considered representative
of the late 1960's to early 1970's because the longer period was one of
fairly consistent hydrological conditions bracketed by the completion
of Shasta Dam on the Sacramento in the early 1940's and by the severe
drought of the mid-1970's.
\20\In fact, no dry or critically dry years, and only one above
normal year occurred during the late 1960's to early 1970's.
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EPA received substantial comment about its choice of an historical
reference period to define the targeted level of protection for the
Estuarine Habitat criteria. One group of comments criticized the choice
of the years included in the reference period. Various other historical
periods were discussed by different commenters as alternatives. (Bay
Institute 1994, California DWR 1994, and NHI 1994). EPA's specific
responses to these comments are in the comment response document
included in the record to this rule.
A second set of comments raised a more fundamental problem with the
use of an historical reference period. These comments argued that the
choice of any particular historical reference period was inherently
suspect if it could not account for the changing ``level of
development'' (that is, the changing system of dams, diversion
facilities, storage reservoirs, etc.) during the 1940 to 1970 period
(California DWR 1994). For example, if exactly the same amount of
precipitation had fallen in each of 1940 and 1970, the different
``level of development'' in each year would affect how much water
actually made its way down the rivers into Suisun Bay. In other words,
the level of development, independent of the amount of rainfall, would
affect the number of days that the 2 ppt salinity value was attained in
Suisun Bay. Without accounting for the level of development, it would
be hard to use rainfall data from the 1940's to represent conditions in
the late 1960's to early 1970's.
EPA is persuaded that addressing these concerns about the effects
of the level of development on resulting salinity criteria is, to a
certain extent, appropriate. EPA and others (notably, the CUWA
scientific workshops) have presented and discussed methods for
accounting for the level of development. The Final Rule includes a
straightforward approach to this issue. Standard statistical regression
analysis was used to isolate the effects on the number of days of 2 ppt
salinity of (1) the level of development, represented by calendar
year,21 and (2) precipitation (Kimmerer 1994b; Ferreira and Meyer
1994). This statistical procedure allowed EPA to separate the effects
of year-to-year variability in precipitation from the effects of
increased levels of upstream development.22
\21\The use of the calendar year as a surrogate for the level of
development is reasonable up until the late 1970's, because up until
that time there was a fairly consistent increase year-by-year in the
number and capacity of diversion and storage facilities, and the
significant changes to the salinity regime imposed by the 1978 Delta
Plan had not yet taken effect. [[Page 4677]]
\22\In that this statistical procedure allowed the effect of the
changing level of development to be controlled, the issue of the
proper data set (i.e., group of reference years) to be included in
the description of historical hydrological conditions essentially
disappears. To take advantage of all appropriate historical data, in
performing these computations EPA used data from the years 1930
(when accurate records were first available) to 1978 (when the
hydrological conditions in the Delta were first substantially
affected by the regulatory measures adopted by the State Board).
---------------------------------------------------------------------------
The results of these recomputations are shown graphically in
Figures 1 and 2. The response surface or curved plane in Figure 2 shows
how the number of days of 2 ppt salinity at Roe Island changes with
both the precipitation (flow) and the changing level of development
over time. Figure 1 shows several ``slices'' of the curved plane in
Figure 2. Each of these different slices corresponds to a particular
year's level of development (1940, 1958, 1968, and 1975), and show how
the number of 2 ppt days would have varied over different hydrological
conditions at that year's level of development. Historically, of
course, each year experienced only one hydrological scenario; the
purpose of the regression equations for these four different years is
to show how that particular level of development would have influenced
the position of the 2 ppt isohaline over the entire range of possible
hydrological conditions.
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Having adjusted the historical data to account for the effects of
the level of development, EPA must still determine the appropriate
reference period for defining the final criteria. The final criteria
must adequately reflect conditions in the estuary at a time period
during which the estuary attained the designated uses, regardless of
the causes of degradation to the waterbody.
In the final rule, EPA is establishing Estuarine Habitat criteria
that replicate the ``level of development'' existing in 1968. The
intent of these criteria is to protect the Estuarine Habitat designated
use to the same degree that these uses would have been protected under
the level of development present in 1968.
EPA chose the 1968 level of development because the best available
information indicates that at that time, salinity conditions in the
Bay/Delta were adequate to protect the estuarine habitat. As explained
in the Proposed Rule, EPA, NMFS, and USFWS have called for a level of
protection equal to that which existed in the late 1960's and early
1970's. EPA believes that the fish population data summarized in the
San Francisco Estuary Project's Status and Trends Report document the
precipitous and unreversed decline of the most abundant species
beginning in 1970. (Herbold et al. 1992). This downward trend is also
apparent in the population data for winter run Chinook salmon. (Herbold
et al. 1992).
In choosing a particular year, EPA is not suggesting that the
particular hydrological conditions in 1968 are being replicated.
Instead, the use of an individual calendar year appears to be a
reasonable surrogate for the level of development for that period. As
the graph in Figure 2 suggests, there would not be a substantial
difference between number of days of meeting the 2 ppt salinity value
in 1968 versus 1967 or 1969. EPA has chosen the 1968 value as a
reasonable representation of the period in which the estuary was
attaining its designated uses.
If the Estuarine Habitat criteria were stated on an annual basis as
it was in [[Page 4678]] the Proposed Rule, the logistic equation
corresponding to the 1968 line in Figure 1 would serve as the
criteria's sliding scale correlating the number of days of meeting the
2 ppt salinity value with annual unimpaired flow. As described below,
however, this annual sliding scale must still be transformed into
monthly sliding scales.
(iii) Moving to Monthly Compliance.
EPA has also refined the final rule to restate the Estuarine
Habitat criteria on a month-by-month basis, rather than as a single
number of days of compliance covering the entire February to June
period.
EPA received comments suggesting that the number of days of meeting
the 2 ppt salinity value at Chipps and Roe Islands should be stated
solely, or largely, in reference to the patterns of precipitation that
could directly affect estuarine habitat during the period intended for
protection. For example, criteria that are designed to protect
conditions in the February-June period should reference only the
unimpaired flows of February-June (or, possibly, January-June).
Including precipitation in months outside of this February-June period
could lead to inaccuracies in the criteria for February-June that could
unnecessarily affect water project operations or inadequately protect
the designated uses. This same problem could exist within the February-
June period. For example, if in a given year the precipitation in
February is substantial, but the following months are very dry, the
overall period of February-June would be considered very dry and, using
the sliding scale for the entire February-June period, the number of
days of compliance with the 2 ppt salinity value at Chipps or Roe
Island would be very low. This result may contradict the actual natural
hydrological cycle, which under this scenario would have provided at
least one high water period for the estuarine habitat uses.
A related issue raised by the comments and in the CUWA scientific
workshops was the problem of how to develop compliance strategies for a
given year based on a forecast of hydrological conditions expected
during the following months. EPA agrees that this forecasting is
unreliable, especially for the critical February and March months which
are typically the months of most variable precipitation. Sliding scales
such as Figure 1 (for Roe Island), which apply to the entire February
to June period of protection, still require the project operators to
forecast future hydrological conditions to meet the expected number of
days of attainment with the 2 ppt criteria. For example, if February
and March are wet, project operators have to forecast weather patterns
for April to June to determine whether they should operate their
projects to meet a substantial number of days of attaining the 2 ppt
salinity value at Chipps or Roe Island (forecasting that the whole
period will continue to be wet) or a lesser number of days (forecasting
that the remaining months will be dry). Thus, the annual or five month
approach described above and shown for Roe Island in Figure 1 would not
address the issue of unreliable forecasts.
To address this uncertainty in forecasting long range hydrology,
and to provide criteria that more closely reflect the natural hydrology
actually affecting the estuarine habitat, EPA is in the final rule
restating the Estuarine Habitat criteria on a month-by-month basis.
That is, the final criteria define the required number of days of
compliance for a particular month solely by reference to the
hydrological conditions of the previous month. This approach more
precisely ties the salinity conditions affecting Estuarine Habitat with
natural hydrological cycles reflecting the time when the estuary
attained its designated uses, and is therefore consistent with EPA's
overall approach to protecting the Estuarine Habitat designated use.
Developing monthly sliding scales. EPA's analysis indicated that
the required number of days of compliance with the 2 ppt criteria in a
given month could be quite accurately predicted from logistic models
using unimpaired flows of any of (a) the current month, (b) the
previous month, (c) the previous two months, or (d) the previous and
current month. Including the actual unimpaired flows of the current
month, however, did not improve model performance and, in practice, the
actual unimpaired flow of the current month cannot be known accurately
until the month is over. EPA has, therefore, restated the criteria
using the logistic equations described above, but only for one month at
a time based on the preceding month's unimpaired flow.
For example, the measured unimpaired flow in January would be used
to set the number of days of compliance with the 2 ppt criteria at the
Chipps and Roe Island locations. Similarly, measured unimpaired flow in
February is used to set March's requirement. This approach has been
labeled the ``Previous Month's 8-River Index'' (PMI) approach. To make
this approach work, the sliding scales exemplified (for Roe Island) in
Figure 1 have been transformed into monthly sliding scales. These
monthly logistic equations for both Chipps and Roe islands are shown
graphically in Figure 3.
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Two technical revisions are being made to the criteria values
generated by these monthly sliding scale equations. First, to
facilitate compliance, the number of days resulting from the monthly
equations will be rounded up or down to the nearest whole number.
Second, at extremely low flows, the monthly equations include
unjustified extrapolations beyond the existing data. For that reason,
when the previous month's index is less than 500,000 acre-feet, the
number of days of compliance required for the current month shall be
zero.
Revising the Roe Island ``trigger'' for monthly compliance. As a
result of the above changes to the Estuarine Habitat criteria, the
``trigger'' for the Roe Island location must be restated as a month-to-
month trigger. The Proposed Rule stated, in effect, that if the
salinity dropped below 2 ppt at Roe Island at any time during the
February to June period due to uncontrolled hydrologic conditions, the
Roe Island requirements were ``triggered'' for the remainder of the
February to June compliance period. In the final rule, the ``trigger''
is evaluated on a monthly basis. If the 14-day moving average salinity
at Roe Island falls below 2 ppt on any day during the last 14 days of a
month, compliance with the Roe Island criteria would be ``triggered''
for the following month.
For example, assume that the sliding scale of unimpaired flow (PMI)
for January indicates that the 2 ppt salinity value shall be attained
for 18 days at Roe Island in February, if the Roe Island criteria is
``triggered.'' If the 14-day moving average salinity in the last part
of January is below 2 ppt at Roe Island, the Roe Island criteria would
in fact be triggered for 18 days in February. Assume then that the
system is operated to meet the 18 days in February, but that a large
storm in mid-February results in the salinities of less than 2 ppt at
Roe Island for the entire month of February. This would ``trigger'' the
Roe Island criteria in March. If the sliding scale, PMI-based
calculation required 31 days of compliance at Roe Island in March in
this scenario, compliance for April (for 13 days, for example) would
also be triggered, since the 2 ppt would be met during the last 14 days
of March. If April is a dry month, the 2 ppt criteria could be met for
the required 13 days early in the month, the 14-day moving average
salinity in the last half of April would never go below 2 ppt at Roe
Island, and the Roe Island criteria would not be triggered for May at
all.
Although somewhat complicated, this monthly triggering mechanism is
essential to assure that the criteria applicable in a given month
reflect the actual distribution of storm events throughout the February
to June compliance period. As explained in more detail above,
accounting for the natural hydrologic cycles in a manner reflecting the
reference period assures protection of the designated uses without
unnecessarily affecting water project operations.
(iv) Alternative Measures of Attaining the Criteria.
In the Proposed Rule, EPA indicated that it believed a State Board
implementation plan that relied on the salinity-flow models, without
making additional allowances for ``confidence intervals'', would
adequately protect the designated uses. EPA's further review of the
comments and continued discussions with the project operators has
confirmed this belief.
In addition, EPA believes that the Estuarine Habitat use would be
protected if the Estuarine Habitat criteria are directly measured as
either a daily salinity value or as a 14-day moving average salinity
value. Further, EPA's review of the new CCWD model correlating flow and
salinity suggests that the Estuarine Habitat use would be protected at
the Chipps and Roe Island monitoring sites if the modeled ``flow
equivalent'' of the applicable 2 ppt criteria is provided. According to
the CCWD model, the steady state flows that would satisfy these flow
equivalent requirements are 29,220 cubic feet per second (cfs) for the
Roe Island monitoring site and 11,400 cfs for the Chipps Island
monitoring site (Denton, pers. comm.). This ``flow equivalence''
measure of attainment with the criteria would not be available at the
Confluence monitoring site because of assumptions in the CCWD model
about antecedent conditions in Suisun Bay.23 [[Page 4680]]
\23\That is, to make this finding that the ``flow equivalence''
would protect the designated use at the Chipps and Roe Island
locations, EPA had to make assumptions in the CCWD model that the 2
ppt salinity value was actually being attained at the Confluence.
Given that assumption, EPA cannot find that the ``flow equivalence''
at the Confluence is protective.
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Accordingly, the State Board could adopt an implementation plan
providing that project operators would attain the criteria in any one
of three ways: (1) the daily salinity value meets the requirement, (2)
the 14-day moving average salinity meets the requirement, or (3) at the
Chipps and Roe Island monitoring sites, the system is operated on that
day so as to meet the ``flow equivalent,'' using the CCWD model, of the
stated salinity criteria. EPA notes that the available modeling data
indicate that under most circumstances, the most efficient approach (in
terms of water usage) to meeting the criteria would be to attain the
specified salinity value rather than the alternative flow equivalent.
c. Revised Estuarine Habitat Criteria
Final estuarine habitat criteria reflecting the changes discussed
above are shown below at 40 CFR 131.37(a)(1). These revised criteria
provide the many equations necessary to define month-by-month sliding
scales and, thereby, the applicable criteria.
For illustration purposes only, Table 2 presents representative
examples of the required number of days of compliance in different
months across a range of possible values of the PMI index of unimpaired
flow.
----------------------------------------------------------------------------------------------------------------
Chipps Island Roe Island (if triggered)
PMI -----------------------------------------------------------------------------------------------------
Feb Mar Apr May Jun Feb Mar Apr May
----------------------------------------------------------------------------------------------------------------
1000...... .......... 31 2 0 0 13 4 2 0
1250...... .......... .......... 7 0 0 17 7 4 0
1500...... .......... .......... 15 0 0 19 10 8 0
1750...... .......... .......... 21 0 0 21 13 11 0
2000...... .......... .......... 26 1 0 22 16 15 0
2500...... .......... .......... 29 16 1 24 20 21 2
3000...... .......... .......... 29 29 7 25 24 25 5
4000...... .......... .......... 30 31 25 26 27 28 18
5000...... .......... .......... .......... ......... 29 27 29 29 26
[[Page 4681]]
6000...... .......... .......... .......... ......... 30 28 30 30 29
----------------------------------------------------------------------------------------------------------------
Table 2. Examples of required number of days of compliance for each month across a range of possible values of
the 8-River Index for the prior month (PMI).
2. Fish Migration Criteria
a. Overview
(1) Importance of the Fish Migration and Cold Freshwater Habitat
Criteria. The State's designated uses for the Bay/Delta include Cold
Fresh-Water Habitat ``to sustain aquatic resources associated with a
coldwater environment,'' and Fish Migration to ``[p]rovide[ ] a
migration route and temporary aquatic environment for anadromous or
other fish species.'' (1991 Bay/Delta Plan at 4-1). The migratory fish
species associated with the cold fresh-water environment in the Bay/
Delta are chinook salmon (Oncorhynchus tshawytscha) and steelhead trout
(Oncorhynchus mykiss).\24\
\24\The State Board has designated both of these uses for the
Bay/Delta estuary. However, in practice there is substantial overlap
between them because many of the factors affecting the Cold Fresh-
Water Habitat use also affect those anadromous fishes migrating
through the Delta to the ocean. Because of this overlap, this rule
will, in protecting Fish Migration, benefit the Cold Fresh-Water
Habitat use as well.
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Currently there are four distinct populations of salmon in the
Sacramento/San Joaquin river systems, each named for the season of
their migration upstream as adults. The fall-run population is now the
most numerous. The San Joaquin River system supports only a fall-run
population; the San Joaquin River spring-run became extirpated in the
1940's. The Sacramento River system still supports small winter-run,
spring-run and late fall-run populations, but these populations have
all declined dramatically in recent years (USFWS 1992a, WRINT-USFWS-7;
California DFG 1992a, WRINT-DFG-14). The winter-run population is now
listed as threatened under the ESA. The spring-run population has
recently reached low enough levels to be recognized as a species of
special concern by the State of California, and NMFS has recently
included the spring-run in its status review of salmon on the northwest
coast of the United States (59 FR 46808 (09/12/94)).
Steelhead trout are also cold fresh-water migratory fish within the
Sacramento River System. They have suffered a 90 percent decline since
the late 1960's, and are supported largely by hatchery production (CDFG
1992a, WRINT-DFG-14).
Salmon and steelhead migrating through the Delta to the ocean are
subject to increased mortality when exposed to high temperatures and
low flows and when diverted out of the main channels of the Sacramento
and San Joaquin Rivers into less suitable habitat. Those fish diverted
from the main river channels into the central and south Delta are also
subject to increased mortality because of several factors including
higher temperatures, increased predation and increased entrainment at
the State and Federal pumping plants in the south Delta (USFWS 1992a).
State and federal legislators have recognized the serious threat to
the continued existence of migratory fishes in the Bay/Delta. In 1988,
the California State legislature mandated a restoration goal of
doubling natural salmon and steelhead production by the year 2000, and
required development of a plan to meet this goal. Salmon, Steelhead
Trout, and Anadromous Fisheries Program Act; codified at Cal. Fish &
Game Code Sec. 6900 et seq. (West 1991). Also, the United States
Congress recently enacted the Central Valley Project Improvement Act
(CVPIA), which requires that a program be developed and implemented to
make ``all reasonable efforts to ensure that * * * natural production
of anadromous fish in Central Valley rivers and streams will be
sustainable, on a long-term basis, at levels not less than twice the
average levels attained during the period 1967-1991. * * *'' Central
Valley Project Improvement Act Sec. 3406(b)(1), P.L. 102-575.
(2) Proposed Rule. Many different factors affect the ability of
salmon and steelhead to successfully migrate through the Delta to the
ocean. These include water temperature, flow rates, diversions,
operation of pumping facilities, and gate closures regulating the
direction of water flows through the myriad channels and sloughs in the
Delta. Clearly, any number of beneficial combinations of these factors
could result in conditions that provide for successful migration and
protection of the designated use. Accordingly, in formulating its
Proposed Rule, EPA concluded that it would state its criteria
generally, measuring the success of salmon in migrating through the
Delta. That is, EPA would state goals that (1) called for a certain
percentage of salmon to be able to survive their passage through the
Delta, and (2) that could be achieved by any of a number of different
management measures. In this way, the State Board would have maximum
latitude to find combinations of management measures that would attain
the salmon survival goal.
In order to quantify the success of migrating salmon in passing
through the Delta, EPA relied on ``salmon smolt survival models''
developed by the USFWS, one for the Sacramento River and one for the
San Joaquin River.\25\ These salmon smolt survival models are
mathematical equations stating the relationship between specific
variables in the Delta (water flow rates, diversions into the central
Delta, etc.) and salmon smolt survival.\26\ To predict the effect of a
particular set of management measures (for example, a specified minimum
flow and a specified maximum export flow), EPA inserts the management
measures into the model equation. The model equation then generates an
``index value'' representing the relative success of salmon migrating
through the Delta while that set of management measures is being
implemented.\27\
\25\A ``smolt'' is a salmon in the process of acclimating to the
change from a fresh water to a salt water environment. This occurs
when young salmon migrate downstream through the Delta to the ocean.
\26\These salmon smolt survival index equations were based in
large part on the results of tagged-fish release and recapture
experiments designed to measure and compare salmon smolt survival
under a number of different physical conditions of varying migration
pathways, water temperatures, flow rates, and rates of water exports
from the Delta.
\27\There was some disagreement among the commenters on the
Proposed Rule as to whether these USFWS models yield index values
that are literally ``percentages'' of the salmon smolts surviving
through the Delta. All parties appear to agree, however, that these
index values do in fact represent the relative survival compared to
other index values. This preamble and accompanying rule will
generally refer to these values as index values rather than as
percentages.
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As its criteria, EPA proposed a set of index values representing
successful salmon migration sufficient to protect the designated use.
EPA established these target criteria index values by taking a set of
USFWS recommendations of management measures that would protect the
salmon resource, and translated (using the USFWS model equations) those
protective management measures into index values. In other words, the
criteria index values represented the level of salmon migration
survival through the Delta that would occur if this particular set of
protective management measures were adopted. The intent was not to
mandate those particular management measures. Rather, it was to set a
performance standard--measured by the criteria index value--for salmon
survival. To attain the goal, the State Board would use either the
specific management measures recommended by USFWS, or any other
combination of measures that would yield the same level of survival of
migrating salmon.
The Proposed Rule named its criteria index values ``salmon smolt
survival index criteria.'' For each of the Sacramento and San Joaquin
River systems, the criteria provided a salmon smolt survival index
equation (i.e. a USFWS model equation) and a set of index values to be
attained. The index equation for each river quantified and predicted
the survival of salmon smolt migrating through the Delta.
The USFWS equations and EPA's Proposed Rule both ``scaled'' the
index values to a scale of 0 to 1. This was done by dividing
experimental release results by a constant of 1.8 (the highest release
result). In the final rule, EPA is not ``scaling'' its criteria values.
It is important to realize that criteria index values in the final rule
are not actual survival estimates (such as a percentage of smolt
surviving), but indices showing survival relative to other index
values.\28\
\28\For example, historically, the San Joaquin River index value
has reached a number as high as 1.5 (which was attained in an
experimental release at Jersey Point). For comparison, the average
San Joaquin survival index value during low flow years is 0.09. This
0.09 index value represents approximately 5 smolt recoveries from a
release of 50,000 fish at Mossdale, 55 miles upstream of the
recovery site at Chipps Island.
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In the Proposed Rule, the index values contained in the criteria
varied according to the standard five water year types--each water year
type had a [[Page 4684]] particular index value to be attained.\29\ The
index values were to be attained by implementing management measures
affecting the variables included in the index equations. For the
Sacramento River, the index equation described a relationship between
smolt survival and three variables: water temperature, water diversion
out of the mainstem Sacramento River, and water export rates. For the
San Joaquin, the variables were river flow rates, water diversion into
the Upper Old River, and export rates.
\29\As stated above, the standard water year categories are wet,
above normal, below normal, dry, and critically dry years.
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The Proposed Rule included index values generally representing the
modeled results of the management measures developed by the USFWS based
on the work of the Delta Team of the Five Agency Chinook Salmon
Committee.\30\ These management measures consist of export limits,
minimum flows, channel gate closures, etc., during critical periods in
the year. The estimated effects of these management measures on smolt
survival were calculated using the criteria index equations.\31\ EPA
concluded that these management measures, and the associated criteria
index values, would lead to the protection of the designated Fish
Migration use.
\30\This interagency group consists of representatives from the
USFWS, California DFG, California DWR, NMFS, and USBR. Its reports
(Five Agency Delta Salmon Team, 1991a; 1991b) represent a consensus
on the most effective and feasible implementation measures to
protect downstream migrant salmon smolts in the Delta.
\31\That is, management measures were evaluated as to their
effect on the variables included in the index equations, and the
index equations were then computed to derive criteria index values.
The result was criteria index values that reflect the effects on
survival of the recommended management measures.
---------------------------------------------------------------------------
The resulting criteria index values were also consistent with the
recommendations of the Interagency Statement of Principles signed by
EPA, NMFS, and USFWS, which called for a level of protection for
aquatic resources equivalent to the level existing in the late 1960's
to early 1970's. To make this comparison, EPA compared its proposed
criteria index values with the index values attained historically on
the two river systems. See generally the discussion in the preamble to
the Proposed Rule at 59 FR 824. The proposed Sacramento River criteria
index values represented overall protection for the Fish Migration use
at approximately the 1956-1970 historical level, whereas the proposed
San Joaquin River criteria index values represented slightly better
protection than the 1956-1970 historical level.
The Proposed Rule also relied on the criteria index equations to
determine whether the criteria were being attained. In effect,
attainment would be assumed if the State adopted an implementation plan
with a set of measures (export restrictions, flow requirements, etc.)
that, when computed in the index equations, resulted in the criteria
index value.
(3) Final Criteria. EPA received substantial comment on its
Proposed Fish Migration criteria. In addition, CUWA sponsored a number
of scientific workshops to discuss the Proposed Rule, and EPA
participated in these discussions. In response to the comments and
scientific workshops, EPA developed a revised approach to the Fish
Migration criteria, which was summarized in the documents made
available to the public in EPA's Notice of Availability published in
the Federal Register on August 26, 1994 (59 FR 44095).
The final rule maintains the fundamental approach of the Proposed
Rule, but it has been revised in a number of ways to address several
concerns. The major changes are:
(i) The methodology for establishing the criteria index values has
been revised. Consistent with the discussion in the materials made
available in the Notice of Availability, the criteria values on the
Sacramento and San Joaquin River systems are described separately and
the index values have been derived in different ways.
(a) On the Sacramento River, the criteria index values vary
according to the water temperature at Miller Park. ``Ceiling'' and
``floor'' criteria index values are included to reflect the fact that
at very high water temperatures, the Fish Migration use needs
additional protection, and at very low water temperatures, temperature
is unlikely to affect fish migration. The actual index values have been
set to replicate the survival values that would be attained if the
Delta Cross-Channel\32\ were closed during the critical migration
period. The Sacramento River tagged-fish release results indicate that,
except in very high temperature periods, those periods in which the
Delta Cross-Channel is closed provide aquatic conditions allowing for
the protection of the Fish Migration designated use.
\32\The Delta Cross Channel is a controlled diversion channel
between the Sacramento River and Snodgrass Slough. Water is diverted
from the River through the Slough and then through natural channels
for almost 50 miles southward to the State and Federal pumping
plants.
---------------------------------------------------------------------------
(b) On the San Joaquin River, the criteria index values vary
according to unimpaired San Joaquin river flow. The actual index values
have been set to approximately replicate the survival values that would
be attained if a series of management measures (flow requirements,
export restrictions, barriers, etc.) recommended by the USFWS based on
the work of the Delta Team of the Five Agency Chinook Salmon Committee
were implemented. The tagged-fish release results indicate that these
or equivalent management measures are necessary to protect the Fish
Migration designated use on the San Joaquin.
(ii) The criteria have been restated as sliding scales or
continuous functions. As described in EPA's alternative formulation of
the Fish Migration criteria referenced in the Notice of Availability,
59 FR 44095, and as in the case of the Estuarine Habitat criteria
discussed above, stating the criteria index values with reference to
the five water year types may create problems\33\ in protecting the
Fish Migration use. Accordingly, the final criteria index values are
expressed as a continuous function.
\33\For example, if a mid-year change in water year types
occurs, the Proposed Rule may have called for drastic changes in the
flow regime, potentially leading to dewatering or washing away
newly-spawned eggs.
---------------------------------------------------------------------------
(iii) Direct experimental measurements of salmon survival through
the Delta will be used to estimate attainment of the criteria, instead
of relying on estimates of attainment generated by the criteria index
equations. This change allows the State Board more flexibility to
develop implementation measures because it does not tie attainment of
the criteria to the particular variables (exports, flows, etc.)
included in the criteria index equations. This also transforms the
final criteria into an explicit ``performance standard'', in which the
criteria index values serve as the statement of desired protection for
the Fish Migration use.
b. Detailed Discussion
(1) Proposed Rule
To protect the Fish Migration designated use, the Proposed Rule
included ``salmon smolt survival index criteria.'' For each of the
Sacramento and San Joaquin River systems, the criteria provided a
salmon smolt survival index equation and a set of index values to be
attained. The index equation for each river quantified and predicted
the survival of salmon migrating through the Delta.
These index equations were developed by the USFWS (Kjelson, et al.
1989; USFWS 1992a, 1992b), and were based on the results of tagged-fish
[[Page 4685]] release and recapture experiments measuring and comparing
salmon smolt survival under a number of different physical conditions
of varying migration pathways, water temperatures, flow rates, and
rates of water exports from the Delta. On the Sacramento River, over
the past 14 years, USFWS has performed a series of studies, releasing
coded-wire tagged smolts at Sacramento and using recapture data to
estimate an index of their survival to Chipps Island. Similarly, on the
San Joaquin River, between 1982 and the present, the USFWS has
conducted a series of experimental releases and captures of tagged
salmon smolts in the San Joaquin River system, and has used the data
collected in these experiments to develop a smolt survival index model
for that basin (Brandes 1994).\34\ EPA believes that the smolt survival
indices from these releases do in fact represent the pattern of smolt
survival through the Delta, and this belief was generally confirmed by
the scientific workshops sponsored by CUWA (Kimmerer 1994b). As noted
above, USFWS and the EPA Proposed Rule both ``scaled'' the index values
by dividing experimental release results by 1.8.
\34\Since the Proposed Rule was published, and as described in
the alternative formulation of the Fish Migration criteria made
available in EPA's Notice of Availability (59 FR 44095), USFWS has
developed a revised version of the San Joaquin River model. This
model relates the survival of San Joaquin basin smolts migrating
through the Delta to: (1) San Joaquin River flow at Vernalis, (2)
proportion of flow diverted from the mainstem San Joaquin River, (3)
exports, and (4) temperature at Jersey Point. The revised San
Joaquin model structure overall is very similar to that of the
Sacramento basin model. This revised model should be more useful
than the previous version for analyzing alternative implementation
measures.
---------------------------------------------------------------------------
In the Proposed Rule, the index values contained in the criteria
varied according to the standard five water year types. The proposed
criteria index values were stated in tabular form as in Table 3, below.
The index values were to be attained by implementing management
measures affecting the variables included in the index equations. For
the Sacramento River, the index equation stated a relationship between
smolt survival and three variables: water temperature, water diversion
out of the mainstem Sacramento River, and water export rates. For the
San Joaquin, the variables were river flows rates, water diversion into
the Upper Old River, and export rates.
The Preamble to the Proposed Rule discussed in detail how the
actual criteria index values in Table 3 were determined. To protect the
designated uses, the Proposed Rule included index values representing
the modeled results of the management measures proposed by USFWS based
on the work of the Delta Team of the Five Agency Chinook Salmon
Committee, with the exception of certain recommendations regarding the
Georgiana Slough. The management measures consisted of export limits,
minimum flows, channel gate closures, etc., during critical periods in
the year. As explained in the preamble to the Proposed Rule (59 FR
825), EPA was concerned that the Delta Team recommendation to close the
Georgiana Slough would have deleterious effects on the Delta smelt and
other aquatic life in the central Delta, and possibly on adult salmon
returning upstream. Thus, the management measures underlying the
recommended criteria index values did not assume that the Slough would
be closed. EPA concluded that these management measures, if implemented
by the State, would lead to the protection of the designated Fish
Migration use.
EPA then evaluated the effects of these management measures on the
variables contained in the models, and calculated the criteria index
values using the model's equations. The result was criteria index
values that reflect effects on survival as a result of implementing the
recommended management measures.
Although the criteria index values were set by reference to the
protective management measures, the resulting criteria index values
were also consistent with the recommendations of the Interagency
Statement of Principles signed by EPA, NMFS, and USFWS, which called
for a level of protection for aquatic resources equivalent to the level
existing in the late 1960's to early 1970's. To make this comparison,
EPA compared its proposed criteria index values with the index values
attained historically on the two river systems. The historical index
values were developed by the USFWS. See USFWS, 1992c (WRINT-USFWS-8);
also 59 FR 824. The proposed Sacramento River criteria index values
represented overall protection for the Fish Migration use at
approximately the 1956-1970 historical level, whereas the proposed San
Joaquin River criteria index values represented slightly better
protection than the 1956-1970 historical level. Both sets of criteria
index values represented better protection than the 1956-1970
historical period in drier years, and less protection in wetter years.
These proposed criteria index values were intended to reflect more
consistent smolt survival and help avoid situations where extraordinary
measures would be necessary to preserve runs, particularly in the San
Joaquin River tributaries.
Table 3.--Proposed Salmon Smolt Criteria
------------------------------------------------------------------------
Sacramento River San Joaquin River
------------------------------------------------------------------------
Criteria Criteria
Water year type value Water year type value
------------------------------------------------------------------------
Wet...................... .45 Wet...................... .46
Above Normal............. .38 Above Normal............. .30
Below Normal............. .36 Below Normal............. .26
Dry...................... .32 Dry...................... .23
Critical................. .29 Critical................. .20
------------------------------------------------------------------------
Finally, the Proposed Rule also relied on the criteria index
equations to determine whether the criteria were being attained. In
effect, attainment would be assumed if the State adopted an
implementation plan with a set of measures (export restrictions, flow
requirements, etc.) that, when computed in the index equations,
resulted in the criteria index value. This approach assumed that the
criteria index equations included all of the important variables
determining smolt survival and correctly stated the interrelationship
of those variables, so that actual measurement of attainment would be
unnecessary.
The final Fish Migration criteria reflect the following changes
from the Proposed Rule: (i) the methodology for establishing the
criteria index values has been revised, (ii) the criteria have been
restated as sliding scales or continuous functions, and (iii) direct
experimental measurements of salmon survival will be used to measure
attainment of the criteria.
(i) Revised Method of Selecting Criteria Index Values
As discussed in the materials referenced in EPA's Notice of
Availability (59 FR 44095), EPA has revised its approach to stating and
developing the criteria index values used in the final criteria. The
primary change in the final rule is that EPA has revised the underlying
management measures used to generate the criteria index values. On the
Sacramento River, available information indicates that closing the
Delta Cross Channel during the spring migration period is the most
important factor in the protection of the Fish Migration designated
use, primarily because closing the Channel prevents migrating fish from
being pulled into the inner Delta where survival is significantly
lower. Accordingly, the criteria index values were based on tagged-fish
release results for migration periods when the Delta Cross Channel was
closed. Similarly, [[Page 4686]] EPA believes that on the San Joaquin
River the management measures recommended by USFWS (with the minor
adjustments described below) will protect the designated uses.
Accordingly, the criteria index values for the San Joaquin were derived
from the modeled values associated with these management measures.
(a) Sacramento River Fish Migration Criteria
On the Sacramento River, the criteria index values vary according
to the water temperature at Miller Park at the time of the tagged fish
release. ``Ceiling'' and ``floor'' criteria index values are included
to reflect the fact that at very high water temperatures, the Fish
Migration use needs additional protection, and at very low water
temperatures, temperature is unlikely to affect fish migration. The
actual index values have been set to replicate the survival values that
would be attained if the Delta Cross-Channel were closed during the
critical spring migration period. The Sacramento River tagged-fish
release results indicate that, except in very high temperature periods,
those periods in which the Delta Cross-Channel is closed provide
aquatic conditions allowing for the protection of the Fish Migration
designated use.
(I) Using Temperature as the Independent Variable for the Criteria.
In the Proposed Rule, Sacramento River criteria varied according to
water year types reflecting precipitation in the Sacramento River
Basin. Using water year type as the ``independent variable'' in the
criteria allowed EPA to match criteria index values with the natural
variation in precipitation. Further analysis of the USFWS tagged-fish
release studies suggests that temperature is a dominant factor
influencing salmon smolt survival in the Sacramento River. Temperature
at release alone is significantly related to salmon smolt survival
(Letter from P. Fox to L. Hoag, California Urban Water Agencies, dated
July 13th, 1994).
Because water temperature in the Delta is largely independent of
management measures in the Delta (in that it varies naturally with
ambient weather conditions), EPA will adopt final Fish Migration
criteria that vary based on water temperature. That is, the criteria
index values will call for higher smolt survival at lower water
temperatures, and lower smolt survival at higher water temperatures.
This variation in the criteria index values with temperature follows
the pattern of the natural variability of temperature and survival
existing on the Sacramento River during periods in which the Fish
Migration designated use is attained.
Although it is generally adopting water temperature as the
independent variable for the Sacramento River Fish Migration criteria,
EPA is modifying the approach in two ways in order to better protect
the designated use. First, at very high water temperatures (those above
72 deg. F), measured smolt survival index values approach zero. These
high temperature conditions are clearly not consistent with protection
of the Fish Migration use. Protective measures should therefore be used
to increase survival of smolts throughout this period, even at times of
high temperature. To this end, USFWS has recommended additional
management measures (primarily export restrictions) to restrict passage
of fish into the warm waters of the central Delta and, thus, lower
mortality of smolts as they pass through the Delta (USFWS 1992a). It is
EPA's judgment that these measures should be used to reduce the serious
degradation in migration conditions occurring during high temperature
periods. EPA believes, therefore, that a ``floor'' to the Fish
Migration criteria is appropriate so as to encourage efforts to protect
salmon during these periods of high temperature. EPA has included such
a ``floor'' at the 72 deg. F temperature level in its final Sacramento
River Fish Migration criteria.
Similarly, at lower temperatures, the smolt survival index values
likely approach a maximum at some point. The highest survival index
recorded (1.48) coincided with the lowest temperature at release
recorded during salmon smolt survival experiments (61 deg.F). Below
this temperature, it is unlikely that lower water temperatures would
lead to a substantially increased survival. In other words, once water
temperature reaches the lower temperatures beneficial to smolt
survival, additional decreases in the temperature would not be expected
to significantly increase survival. This suggests that the Fish
Migration criteria should include a ``ceiling'' value associated with
those low temperatures. Otherwise, the criteria would state that
continued lowering of water temperature should yield higher and higher
survival. This result is unlikely to be valid. EPA is therefore placing
a ``ceiling'' on the criteria index values corresponding to the
61 deg.F level.
(II) Establishing criteria values. To set the actual criteria
values, the final rule relies on the recommendation by USFWS that the
Delta Cross Channel be closed at critical times during the spring
salmon migration period (USFWS 1992a). Recent investigations by USFWS
indicate that closing the Delta Cross Channel is the most important
factor in the protection of smolts on the Sacramento River (USFWS
1992b). The historical experimental release results support this
hypothesis, in that data points derived from periods when the Cross
Channel was closed show a significant and consistent improvement in
survival compared to periods when it is open (USFWS 1992b).35
\35\This is particularly true for release studies at Sacramento.
Release studies at Courtland (downstream of Sacramento) showed less
dramatic improvement with the Cross Channel closed, suggesting that
other factors such as those included in the USFWS model are also at
work.
---------------------------------------------------------------------------
Based on this beneficial relationship between survival and the
closure of the Delta Cross Channel, EPA has concluded that criteria
index values corresponding to a closed Delta Cross Channel (adjusted to
provide a floor for high temperature periods) would reflect conditions
protecting the Fish Migration designated use on the Sacramento River.
Accordingly, the final rule adopts criteria index values, stated (as
explained below) as a continuous function or line, to
approximate36 the experimental survival index values observed for
Sacramento releases during periods in which the Channel is closed. The
continuous function or line for these criteria index values can be
stated as a simple linear equation (Index value = 6.96 - .092 *
Fahrenheit temperature).
\36\Approximating this line was done through a standard least
squares ``best fit'' computation.
---------------------------------------------------------------------------
This approach to developing criteria index values addresses some of
the concerns about the criteria index equations raised in the public
comments and at the CUWA scientific workshops. Some commenters believed
that the complexity and structure of the equations resulted in too much
uncertainty about their statistical reliability. The revised approach
used in the final rule reduces this problem because it sets the
criteria index values using observed tagged-fish release results
instead of modeled or computed values.
The final criteria index value line described above very closely
approximates the line created by doubling the historical survival data
measured at times that the Delta Cross Channel is open. These different
lines, and the underlying data, are summarized in Figure 4. Although
not intentional, the near-coincidence of the final criteria index value
line and the doubling line provides an independent policy rationale for
adopting this target index, in that the Central Valley Project
[[Page 4687]] Improvement Act mandates a ``doubling'' goal for
anadromous fish.
BILLING CODE 6560-50-P
[GRAPHIC][TIFF OMITTED]TR24JA95.005
BILLING CODE 6560-50-C [[Page 4688]]
Historical information confirms the validity of the final
Sacramento River Fish Migration criteria, in that the criteria index
values developed in this final rule are consistent with the modeled
index values representing conditions in the late 1960's to early
1970's. As stated by EPA in the Proposed Rule, the level of protection
on the Sacramento River during this historical period was consistent
with the protection of the Fish Migration designated use.
(III) Revised Sacramento Fish Migration Criteria. The revised
criteria (Sacramento River Fish Migration Criteria or SRFMC) are stated
in reference to water temperature. As explained above, use of this
linear equation appears inappropriate at both very high and very low
temperatures, so the criteria must specify a ceiling on the index
values at low temperatures and a floor for high temperatures.
Incorporation of these conclusions and comments leads to the following
Fish Migration criteria:
At temperatures below 61 deg.F:
SRFMC=1.35
At temperatures between 61 deg.F and 72 deg.F:
SRFMC=6.96 - .092 * Fahrenheit temperature
At temperatures above 72 deg.F:
SRFMC=0.34
In all cases, water temperature is the temperature at release of
tagged salmon smolts into the Sacramento River at Miller Park.
These final criteria are shown in Figure 5. Note that the
``ceiling'' and ``floor'' values in the final rule differ somewhat from
those included in the documents made available in EPA's Notice of
Availability (59 FR 44095). The changes were made to correct
computational errors in evaluating the applicable ``continuous
function'' values for the 61 deg.F and 72 deg.F ceiling and floor
levels.
BILLING CODE 6560-50-P
[[Page 4689]]
[GRAPHIC][TIFF OMITTED]TR24JA95.006
BILLING CODE 6560-50-C
(IV) Implementation. On the Sacramento River, the criteria provide
survival goals that vary based on the water temperature at the time of
release of the tagged salmon smolts. EPA believes that the
implementation plan developed by the State Board should provide for a
sufficient number of fish releases each year to determine whether the
criteria are being attained over a representative range of temperature
conditions. EPA recognizes that there may be substantial variation in
fish migration criteria values resulting from these experimental
releases. Accordingly, the final rule provides that attainment can be
measured using a three-year moving average (the current year and two
preceding years). Three year periods should provide time to complete
sufficient releases to determine whether the implementation measures
are, on average, attaining the stated criteria values.
The State Board may consider using the USFWS Sacramento smolt
survival model (that is, the model underlying the criteria index
equations) to predict measures necessary to attain the criteria. There
are a number of base conditions underlying both the tagged-fish release
experiments and the USFWS models. For example, USFWS recommended a base
Sacramento River flow to ensure that overall conditions do not
deteriorate. The State should protect these base conditions as it
develops an implementation plan.
Monitoring attainment of these criteria should focus on both
within-year measures and across-year comparisons. During each year
monitoring of salmon smolt survival should occur throughout the months
of April, May and June with particular emphasis during times of
temperature change or at times of change in water project operation. It
is likely that this monitoring will reveal a large variability in
survival at different times and under different conditions within each
year. EPA anticipates that at the time of the next triennial review
enough monitoring data over a range of temperatures will be available
for a preliminary determination of whether the State's implementation
actions attain the criteria.
(b) San Joaquin River Fish Migration Criteria
On the San Joaquin River, the criteria index values vary according
to unimpaired San Joaquin river flow. The actual index values have been
set to approximately replicate the survival values that would be
attained if a series of management measures (flow requirements, export
restrictions, barriers, etc.) recommended by the USFWS were
implemented. The tagged-fish release results indicate that these or
equivalent management measures are necessary to protect the Fish
Migration designated use on the San Joaquin.
(I) Using Unimpaired Flow at Vernalis as the Independent Variable
for the Criteria. In the Proposed Rule, San Joaquin River criteria
varied according to water year types reflecting precipitation in the
San Joaquin River basin. Using the water year type as the ``independent
variable'' allowed EPA to match the criteria index values with the
natural variation in precipitation. Further analysis has confirmed that
water flow at Vernalis shows a significant correlation with survival
indices representing total survival through the Delta,37
suggesting that criteria index values should vary with the natural
hydrology. That is, the criteria index values should reflect higher
survival during wetter years with more precipitation and lower survival
during drier years. This variation replicates the natural hydrological
cycles affecting Fish Migration through the estuary. [[Page 4690]]
\37\EPA considered water temperature at release, smolt size at
release, and water flow at Vernalis as potential independent
variables affecting survival. Based on the studies done to date, it
appears that neither water temperature at release nor smolt size
show a significant correlation with the smolt survival indices
representing smolt survival through the San Joaquin Delta (P. Fox,
Data summary presented at CUWA workshop on June 29, 1994). Note that
results from upstream site releases (at Snelling and on the lower
Stanislaus and Tuolumne Rivers) were included in this correlation
between flow and survival index values in order to supplement data
from wetter years. This approach assumed that the mortality between
the upstream release sites and the downstream Mossdale, Dos Reis and
Upper Old River release sites (all close together) is negligible. If
incorrect, this assumption may bias the correlation downward, and
survival through the Delta may have been better than the index
indicates for those releases.
---------------------------------------------------------------------------
The Proposed Rule varied criteria index values according to the
five water year types, and in that way reflected natural hydrological
cycles. In the final rule, however, EPA is using the 60-20-20
unimpaired San Joaquin flow index38 as a readily-available
estimate of natural hydrology. When used in a continuous function (as
described below), the 60-20-20 index allows a much more precise
statement of the natural hydrology than the five water year categories.
\38\The San Joaquin water year index (denoted the San Joaquin
Valley Index in the final rule language) is the commonly-accepted
method for assessing the hydrological conditions in the San Joaquin
basin. It is also frequently referred to as the 60-20-20 index,
reflecting the relative weighting given to the three terms (current
year April to July runoff, current year October to March runoff, and
the previous year's index) that make up the index.
---------------------------------------------------------------------------
(II) Establishing Criteria Index Values. To establish the actual
values included in the San Joaquin River Fish Migration criteria, EPA
first developed survival values associated with the implementation of
management measures proposed by USFWS (USFWS 1992a). These USFWS
measures include export limits at certain times, a barrier at Old River
during April and May, and minimum flows at Vernalis, and are summarized
in Table 5.39 As indicated in the Proposed Rule, EPA believes that
implementation of these management measures would provide conditions
protecting the designated Fish Migration use.
\39\As explained above, the index values shown in Table 6 (both
USFWS and EPA values) have been ``scaled'' by dividing by 1.8. This
scaling allows a direct comparison with the Proposed Rule index
values, which were also scaled. EPA's final criteria index values
have not been scaled, to facilitate measurement of attainment
through actual experiments as discussed below.
---------------------------------------------------------------------------
Modifying management measures. As explained below, EPA has revised
its assessment of some of the USFWS management measures (notably, those
involving the Upper Old River barrier). Accordingly, the final rule
used the following management measures: (1) A one month (April 15 to
May 15), instead of USFWS's two month (April 1 to May 31), requirement
for the Upper Old River barrier placement, (2) increased export
restrictions (to 1500 cfs) during the time the Old River barrier is in
place, (3) increased flow (to an average of 4000 cfs rather than
USFWS's 2000 cfs) in critical years when the barrier is in place, and
(4) flows and exports varying each year according to the 60-20-20 water
year index, rather than using the USFWS proposal to vary measures by
water year type. EPA's measures (stated as averages for each water year
type) are also shown in Table 4.
EPA revised the management measures recommended by USFWS because
recent discussions with USFWS and others, as well as information
developed in hydrological modeling for the South Delta Barriers Project
(California DWR 1993), raised concerns that an Upper Old River barrier
might increase reverse flows in the central Delta. Such an increase has
the potential to draw fish into poor habitat and to increase
entrainment of fish at the project pumps. This is of particular concern
for the threatened Delta smelt. Because the barrier is expected to
provide greatly increased protection for migrating salmon smolts, EPA
continues to believe, as it expressed in the Proposed Rule, that an
Upper Old River barrier is an important implementation measure.
However, in order to prevent an increase in detrimental central Delta
reverse flows, EPA is revising the USFWS management measures to include
only one month with the barrier in place, rather than the two months
initially recommended by USFWS.40
\40\As in the Proposed Rule, EPA assumed that exports would be
reduced to no more than 1500 cfs while the barrier is in place, to
help alleviate hydrological problems caused by the barrier. Minimum
flows during the time the barrier is in place are assumed to be an
average of approximately 4000 cfs during dry and critically dry
years to provide an increased ratio of flows to exports in the lower
San Joaquin, thereby further reducing potential problems caused by
reverse flows. Management measures assumed in developing the
criteria values also included export restrictions during the times
in April and May when the barrier is not in place. These maximum
export rates are: in critically dry years, 2000 cfs; dry years, 3000
cfs; below normal years, 4000 cfs; above normal years, 5000 cfs; and
wet years, 6000 cfs.
[[Page 4691]]
Table 4.--San Joaquin Management Measures Compared
----------------------------------------------------------------------------------------------------------------
Max Total CVP/SWP Barrier Upper Old Index Values on
Alternative Exports in cfs River Vernalis Flow San Joaquin
----------------------------------------------------------------------------------------------------------------
EPA.............. 4/15 to 5/15 1500 4/15 to 5/15 All Year 4/15 to 5/5 Minimum CFS ..................
4/1 to 4/15 & 5/16 to Types W 10000 W .49\2\
5/31 AN 8000 AN .35
W\1\ 6000 BN 6000 BN .28
AN 5000 D 4000 D .22
BN 4000 C 4000 C .22
D 3000 Other flows from 4/1 to 5/ Avg = .33
C 2000 31 same as DWRSIM run used
by USFWS for D-1630
USFWS............ 4/15 to 5/15 4/1 to 5/31 All Year 4/15 to 5/15 Minimum CFS ..................
W 6000 Types W 10000 W .49
AN 5000 AN 8000 AN .41
BN 4000 BN 6000 BN .40
D 3000 D 4000 D .35
C 2000 C 2000 C .32
Other flows from 4/1 to 5/ Avg = .41
31 same as DWRSIM run used
by USFWS for D-1630
----------------------------------------------------------------------------------------------------------------
\1\Many of the management measures in Table 4 vary by the water year category. Those categories are wet (W),
above normal (AN), below normal (BN), dry (D) and critically dry (C).
\2\For comparison purposes, both EPA and USFWS index values have been scaled by dividing by 1.8. The final EPA
criteria have not been scaled.
Criteria index values. Having arrived at this set of management
measures that would protect the Fish Migration designated use (and not
adversely affect the Delta smelt), EPA used the USFWS survival index
equations to develop criteria index values across the potential range
of hydrological conditions.41 Note that, as distinguished from the
Proposed Rule, EPA is including only the criteria index values as its
final Fish Migration criteria. The Proposed Rule had also included the
criteria index value equations in the criteria. By including only the
goal or target index values in the final criteria, EPA is providing
greater latitude to the State Board to develop a mix of management
measures that attain the stated salmon survival.
\41\The final Fish Migration criteria on the San Joaquin River
do not vary by temperature (as they do for the Sacramento River)
because experimental data from releases near the upstream edge of
the Delta did not show a significant statistical relationship
between survival and temperature at release (P. Fox, Data summary
presented at CUWA workshop on June 29, 1994). In other words, on the
San Joaquin River, temperature should not be used as the independent
variable in the criteria. Nevertheless, temperature at Jersey Point
is one of the factors included in the revised USFWS San Joaquin
River model, and, as described above, that model was used in
developing EPA's final criteria to gauge the probable effect of
implementation measures on smolt survival. When computing modeled
smolt survival, EPA assumed average water temperatures of 60 deg.F
in April and 65 deg.F in May. These assumed values are averages
from a set of temperature data at Jersey Point taken during the late
1950's and 1960's. The recent experimental release temperatures are
within the range of this data.
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Means of these modeled values for each water year type are shown in
Table 4. To translate these discrete values into a continuous function
(as discussed below), two lines of ``best-fit'' were created, one for
the drier years (dry and critically dry) and one for the wetter years
(wet, above normal, and below normal). By connecting these two lines,
EPA created a continuous function to serve as the criteria index value
line on the San Joaquin. This criteria index value line is shown in
Figure 6.
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Dry year v. wet year protection. These final criteria index values
represent a larger relative increase in survival over current survival
rates in dry and critical years (compared to wetter years) so as to
protect salmon populations from declining to the critically low levels
of recent years. The results from tagged-fish releases on the San
Joaquin River show significantly different survival at high versus low
flow conditions (USFWS 1992b; Brandes 1994). Most of the release
studies have been performed at flows below 5,000 cfs, and it is clear
from the relation between survival indices and experimental flow
conditions that these conditions are very poor for smolt survival and
are inadequate to protect the Fish Migration designated uses. The
average survival index for these low flow conditions is 0.09, whereas
these index values have attained values as high as 1.5 on the San
Joaquin (a Jersey Point release).42 Although there is less
information at higher flows, the experimental results do indicate that
survival has been substantially higher under these conditions. The
average survival index at these higher flows is 0.48. [[Page 4693]]
\42\These numbers are not ``scaled'', and are thus indices
showing survival relative to other index values. The 0.09 average
index value represents approximately 5 recoveries from a release of
50,000 fish at Mossdale, 55 miles upstream of the smolt recovery
site at Chipps Island.
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To address this relative difference in survival during high and low
flow periods, EPA is adopting criteria index values reflecting a
relatively larger improvement in survival in low flow years than in
high flow years. That is, conditions for migrating fish in drier
periods have been relatively worse, so the criteria index values
applicable to the drier periods must reflect conditions that are
relatively more improved in order to protect the Fish Migration
designated use.
Although the final criteria call for relatively higher protection
in drier years, it is also particularly important in the San Joaquin
basin to protect salmon during periods of higher flow conditions. The
years of higher flows have been the only times recently when the Fish
Migration use has come close to being attained, and protection in these
productive years is important for buffering the salmon population
against permanent loss of salmon runs when conditions are poor. To
address these special concerns across the spectrum of hydrological
conditions, these final criteria index values, on average, increase wet
year survival by a factor of 1.8 and critically dry year survival by a
factor of 4.
EPA has considered the concerns expressed by some CUWA workshop
participants about using the USFWS models to establish criteria index
values. The CUWA workshop participants developed a consensus, based not
on the USFWS-modeled values but on their independent scientific
judgment, that an increase in measured survival index values of two to
three times recently observed values would be appropriate in critical
years (Kimmerer 1994b). As stated above, the CUWA workshop participants
also endorsed relatively higher protection in drier years as opposed to
wetter years (Kimmerer 1994b). EPA agrees with these scientific
judgments, and believes that measured criteria index values in these
ranges must be attained to protect the designated uses on the San
Joaquin.
The criteria index values shown as a continuous function in Figure
6, even though developed with the assistance of the USFWS model, are
wholly consistent with the findings of the CUWA workshop participants
(Kimmerer 1994b). In addition, these target values are, on average,
consistent with the historical 1956-70 average survival index for the
more protective wetter years of that period (wet, above normal, and
below normal water years) as calculated using the USFWS model (Brandes
1994). The target values are also consistent with the CVPIA goal of
doubling anadromous fish populations. For comparison, the final
criteria index value line is displayed in Figure 7 with the recent
historical survival line (based on the tagged fish release results) and
a line representing twice the recent historical survival line.
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(III) Revised San Joaquin Fish Migration Criteria. The criteria
index value line is being stated in the final rule as follows:
For years in which the SJVIndex is > 2.5:
SJFMI = (-0.012) + 0.184*SJVIndex
In other years:
SJFMI = 0.205 + 0.0975*SJVIndex
where SJFMI is the San Joaquin Fish Migration index, and SJVIndex is
the 60-20-20 San Joaquin water year index in million acre feet (MAF).
These criteria are displayed graphically in Figure 6.
(IV) Implementation of San Joaquin River Fish Migration Criteria.
The following discussion is intended to assist the State Board's
consideration of the issues involved in implementing these or similar,
equally protective, criteria.
The San Joaquin River Fish Migration criteria provide an annual
survival goal that varies depending on the 60-20-20 San Joaquin water
year index. EPA anticipates that the State Board implementation plan
would provide for a sufficient number of tagged fish releases to verify
that the applicable criterion is being met in each year. EPA recognizes
that there may be substantial variation in fish migration criteria
values resulting from these experimental releases. Accordingly, the
final rule provides that attainment can be measured using a three-year
moving average (the current year and two preceding years). Three year
periods should provide time to complete sufficient releases to
determine whether the implementation measures are, on average,
attaining the stated criteria values.
As stated above, the USFWS model is the best available model of
salmon smolt survival through the Delta, and EPA encourages the State
Board to use the recently revised USFWS San Joaquin model as guidance
for setting implementation measures. Nevertheless, it is important to
recognize that there may be constraints on the model's use. Further
monitoring and experimental releases under the chosen implementation
regime are essential to verify and refine the model, and will ensure
that the smolts are actually surviving at the expected level. In
addition, it will be particularly important to protect the base
conditions assumed in the model, such as flows during the time the
Upper Old River barrier is not in place, flows at Jersey Point, and
temperature.
The expected criteria index values are unlikely to be achieved if
these base conditions deteriorate.
One additional refinement to the implementation measures should be
considered on the San Joaquin River. As discussed above, the Sacramento
River criteria include a ceiling value on the maximum salmon smolt
survival. This was included because there appears to be a point where
incrementally lower temperatures do not significantly increase salmon
smolt survival. In theory, there may be a similar point on the San
Joaquin River where incrementally higher flows in very wet years do not
yield significantly higher salmon smolt survival. Nevertheless, the
existing data do not allow quantification of what those flow levels
are. EPA is supportive of another mechanism for dealing with this
issue. It is EPA's judgment that in very wet years (those in which the
flows exceed 10,000 cfs during the relevant period) it may be
appropriate to meet the flow requirements associated with the targeted
Fish Migration criteria index solely through natural storm events and
restricted diversions, and not by upstream reservoir releases. In other
words, the implementation flows could be provided at these higher flow
periods by natural hydrology rather than by reservoir releases. In this
way, the natural ``flood events'' that appear to be so beneficial to
the salmon would be protected, but the water supply system would not
have to bear the water costs of generating artificial flood events
through reservoir releases.
(ii) Use of Continuous Function
The second principal difference in the final criteria is to state
the criteria as a ``continuous function'' or ``sliding scale.'' As
discussed in EPA's alternative formulation of the Fish Migration
criteria made available in the Notice of Availability, this approach
replaces the Proposed Rule's statement of the criteria as single fixed
index values for each of the five water year categories (59 FR 44095).
The proposed approach did not account for the substantial differences
in hydrological conditions within water year types. For example, an
``above normal'' water year type could range from a wet ``above
normal'' year to a dry ``above normal'' year. Given the extreme
variation of hydrological conditions in the Bay/Delta, these variations
within each of the five standard water year types are substantial, and
should be factored into the calculation of the applicable Fish
Migration criteria index value. The continuous function approach
addresses this problem by transforming the five discrete water year
categories into a more precise equation (graphically, a single line or
curve) correlating the Fish Migration criteria index value with each
year's specific observed hydrological conditions. The continuous
function approach provides the same degree of protection for the
designated uses as the proposed approach using average survival values.
However, the continuous function approach provides a more precise
approximation of hydrological conditions and facilitates implementation
and compliance. EPA explained the rationale for using the continuous
function approach in more detail in the technical documents referenced
in the Notice of Availability (59 FR 44095). The derivations of the
actual continuous functions for the Sacramento and San Joaquin River
systems are explained above.
(iii) Measuring Attainment Through Actual Test Results
The Proposed Rule relied on the criteria index equations to
determine whether the criteria were being attained. In effect,
attainment would be assumed if the State adopted an implementation plan
with a set of measures (export restrictions, flow requirements, etc.)
that, when computed in the index equations, resulted in the criteria
index value.
Many commenters believed that reliance on the criteria index
equations for this purpose was inappropriate because factors other than
those implementation measures included in the model may affect smolt
survival. To address this concern, in the final criteria, direct
experimental measurements of smolt survival through the Delta will be
used to estimate attainment of the criteria, instead of relying on
modeled estimates. Survival is to be measured through tagged smolt
release and recapture studies. This approach assures that factors
significantly affecting survival will be reflected in survival
measurements, even if they are not well described by the criteria index
equations. This more direct approach gives the State greater latitude
to develop implementation measures outside of the equation parameters.
It also ensures that the implementation measures are actually providing
the intended protection for the Fish Migration designated use.
(3) Fish Migration Criteria as Multispecies Protection
The Fish Migration criteria outlined above are based on protection
measures required for a single run of salmon, the fall-run Chinook
salmon. Some commenters questioned whether this approach conflicts with
the habitat or multispecies approach recommended by the Club FED
agencies in their [[Page 4696]] Agreement for Coordination on
California Bay/Delta Issues signed September 20, 1993. As noted in the
preamble to the Proposed Rule, EPA believes that the implementation
measures likely to be adopted to meet the target criteria values in
these Fish Migration criteria, when combined with the other Federal
actions in the Delta protecting the endangered winter-run Chinook
salmon, are fully consistent with the protection of a broad range of
anadromous and migratory fishes in the Bay/Delta.
Juvenile spring-run salmon and steelhead move through the Delta
during the same period as winter-run and fall-run salmon, and are
expected to be protected in the Delta by measures protecting these
other runs (CDFG 1990a). Species other than salmon and steelhead
seasonally migrate into and out of the Delta for spawning and as
juveniles. These species include striped bass, Delta smelt, longfin
smelt, white and green sturgeon, American shad and Sacramento
splittail. With the exception of temperature, the factors that lead to
successful migration of salmon and steelhead smolts are also important
for successful migration of the juveniles of these species into the
lower embayments. Therefore, EPA's proposed Fish Migration criteria,
although specifically addressing fall-run Chinook salmon, will also
help protect migration of these other migratory species.
3. Fish Spawning Criteria
a. Proposed Rule
In California, striped bass spawn primarily in the warmer
freshwater segments of the Sacramento and San Joaquin Rivers.
Protection of spawning in both river systems is important to ensure the
genetic diversity of the population as well as to increase the size of
the overall striped bass population. The precise location and time of
spawning appear to be controlled by temperature and salinity (Turner
1972a; Turner and Chadwick 1972). According to the California DFG,
striped bass spawn successfully only in freshwater with electrical
conductivities less than 0.44 millimhos\43\ per centimeter
electroconductivity (mmhos/cm EC), and prefer to spawn in waters with
conductivities below 0.33 mmhos/cm. Conductivities greater than 0.55
mmhos/cm appear to block the upstream migration of adult spawners
(Radtke and Turner 1967; SWRCB 1988; SWRCB 1991; CDFG 1990b, WQCP-DFG-
4). As explained in more detail in the Preamble to the Proposed Rule,
salinity does not appear to be a serious limitation on spawning on the
Sacramento River. However, in the smaller and shallower San Joaquin
River, migrating bass seeking the warmer waters encounter excessive
upstream salinity caused primarily by runoff. This salinity can block
migration up the San Joaquin River, thereby reducing spawning, and can
also reduce survival of eggs (Farley 1966; Radtke 1966; Radtke and
Turner 1967; Turner and Farley 1971; Turner 1972a, 1972b).
\43\Salinity conditions upstream in freshwater are generally
affected by dissolved salts from upstream water runoff. The salinity
content of freshwater is traditionally measured by its
electroconductivity or specific conductance standardized to
25 deg.C, and is expressed in terms of millimhos per centimeter
electroconductivity (``mmhos/cm EC'') or micromhos per centimeter
specific conductance. The Proposed Rule stated the Fish Spawning
criteria in terms of mmhos/cm EC. In the final rule, EPA will state
the criteria in terms of micromhos/cm specific conductance, so as to
be consistent with EPA's published guidance. See 40 CFR Part 136,
Table 1B--List of Approved Inorganic Test Procedures, Parameter 64.
The Proposed Rule's term ``0.44 mmhos/cm EC'' is equivalent to the
final rule's term ``440 micromhos/cm specific conductance''. EPA
will continue using the ``0.44 mmhos/cm EC'' term in this preamble,
so as not to confuse the interested public.
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The State Board's 1991 Bay/Delta Plan established objectives of 1.5
mmhos/cm EC at Antioch and 0.44 mmhos/cm EC at Prisoners Point in April
and May. EPA disapproved these objectives, in part, because they are
not adequate to protect spawning habitat in the reach farther upstream
between Prisoners Point and Vernalis. EPA also disapproved the 1991
Bay/Delta Plan spawning criteria because they were not based on sound
science. The State Board explained that the 1.5 mmhos/cm EC criteria at
Antioch was intended to protect spawning habitat upstream of Antioch
(near Jersey Point), not at the Antioch location itself. The State
Board acknowledged that ``the use of 1.5 [mmhos/cm] EC at Antioch
appears not to be generally appropriate, and proposed that a thorough
review of this [criterion] be undertaken at the next triennial review''
(1991 Bay/Delta Plan, p. 5-32). EPA found this unproven approach of
setting criteria downstream in hopes of attaining different criteria
upstream deficient, and disapproved it.
In the Proposed Rule (40 CFR 131.37(b)), EPA proposed salinity
criteria of 0.44 mmhos/cm EC in the lower San Joaquin River in the
reach from Jersey Point to Vernalis in wet, above normal, and below
normal water years. In dry and critical water years, EPA proposed the
0.44 mmhos/cm criteria for only the reach from Jersey Point to
Prisoners Point.
b. Comments on Proposal and Final Criteria
EPA received a number of comments on its proposed Fish Spawning
criteria. California DFG was generally supportive of the proposed
criteria, but believed that the criteria would need to be supplemented
by a range of additional management techniques in order to have any
substantial benefit for spawning (California DFG 1994). Several parties
noted that striped bass are an introduced predatory species, and that
efforts to increase striped bass populations would work at cross-
purposes with efforts to enhance other species such as salmon and Delta
smelt (City and County of San Francisco Public Utilities Commission
1994; Bay/Delta Urban Coalition 1994; California Farm Bureau Federation
1994). Other commenters raised the possibility that extending the
acceptable spawning habitat upstream could result in more striped bass
being entrained at the State and Federal water project pumps in the
southern Delta. (California DWR 1994). Finally, some commenters
believed that emphasizing the striped bass as an individual species was
inconsistent with the multiple species approach to habitat protection.
(CUWA 1994a).
Although EPA believes there is some merit to each of these
comments, EPA is not making any changes to the Fish Spawning criteria
in the final rule stated at 40 CFR Sec. 131.37(b). EPA believes there
is substantial scientific evidence indicating that increased salinities
in the designated reaches of the San Joaquin River do in fact have an
adverse effect on fish spawning. This problem of increased salt
loadings has been recognized by virtually all the parties (CUWA 1994b;
ACWA 1994) and recommendations on how to address it have been developed
by, among others, the San Joaquin Valley Drainage Program (SJVDP 1990).
The possibility that healthier populations of predatory fishes such
as striped bass would adversely affect other species of concern needs
to be considered in the context of the whole range of protective
measures being developed for the fishery. The package of project
management measures, water quality standards, and implementation
programs being developed under the CWA, ESA, CVPIA, and counterpart
State authorities are intended to address the entire Bay/Delta
ecosystem. For that reason, EPA believes that healthier predatory
species populations should not interfere with the protection of other
species of concern. EPA further believes that, if the State Board
adopts and/or implements these criteria, the State Board can address
the impact of entrainment at the pumps in its implementation measures.
Finally, EPA believes that salinity problems in the lower San Joaquin
affect aquatic species other than the striped bass. Recent research
findings of USFWS (Meng 1994) suggest that the spawning habitat for the
Sacramento splittail (currently proposed for listing as threatened
under the ESA) is also being adversely affected by increased salt
loadings in the lower San Joaquin. Accordingly, these criteria are
consistent with a multiple species approach.
EPA believes that clearly stating the salinity conditions necessary
for protection of the designated fish spawning uses on the lower San
Joaquin provides the foundation for implementation plans by the State
Board and other regulatory agencies. EPA believes that these
implementation plans should build upon the recommendations of the San
Joaquin Drainage Program, to the end that compliance with these
criteria can be effectively and efficiently achieved.
One change has been made to the final Fish Spawning criteria. In
the Proposed Rule, the Fish Spawning criteria were stated with
reference to the five standard water year types, with one criterion
required for dry and critical dry water years and another criterion
required for the remaining water year types. In the final rule,
reliance on water year types is eliminated. Instead, deciding which of
the two different criteria applies is made by reference to the San
Joaquin Valley Index, the standard index of San Joaquin Valley flows.
This change merely eliminates the unnecessary middle step of
translating the San Joaquin Valley Index into the five water year
types.
4. Suisun Marsh Criteria
The tidal wetlands bordering Suisun Bay are characterized as
brackish marsh because of their unique combination of species typical
of both freshwater wetlands and more saline wetlands. Suisun Marsh
itself, bordering Suisun Bay on the north, is the largest contiguous
brackish water marsh in the United States. These large tidal marshes
are distinct from the approximately 44,000 acres of ``managed'' marshes
in the Suisun Bay, which are currently diked and managed for waterfowl
use and hunting. Approximately 10,000 acres of marshes, both along
channels within Suisun Marsh and bordering Suisun Bay, are still fully
tidal (Meiorin et al. 1991).
These tidal marshes provide habitat for a large, highly diverse,
and increasingly rare ecological community. The recent ``Status and
Trends'' reports published by the SFEP listed 154 wildlife species
associated with the brackish marshes surrounding Suisun Bay (Harvey, et
al. 1992), including a number of candidates for listing under the ESA.
These include the Suisun song sparrow (Melospiza melodia maxillaris)
and the Suisun ornate shrew (Sorex ornatus sinuosus), as well as the
plants Suisun slough thistle (Cirsium hydrophilum var. hydrophilum),
Suisun aster (Aster chilensis var. lentus), delta tule pea (Lathyrus
jepsonii), Mason's lilaeopsis (Lilaeopsis masonii), and soft-haired
bird's beak (Cordylanthus mollis mollis). These rare species are all
found exclusively in tidally inundated marsh.
Recent studies indicate that increases in salinity caused by a
combination of upstream diversions and drought have adversely affected
the tidal marsh communities (Collins and Foin 1993). As salinity has
intruded, brackish marsh plants which depend on soils low in salt
content (especially the tules Scirpus californicus and S. acutus) have
died back in both the shoreline marshes and in some interior marsh
channel margins of the western half of Suisun Bay. These plants have
been replaced by plants [[Page 4699]] typically growing in saline
soils, especially cordgrass (Spartina foliosa). This has been
associated with erosion of the marsh margins. In addition, tules in the
upper intertidal zone have been replaced by the smaller and more salt
tolerant alkali bulrush (Scirpus robustus). These changes have
significantly affected available habitat for a variety of wildlife that
nest and feed in these areas, including the Suisun song sparrow, marsh
wren, common yellowthroat, black-crowned night heron, and snowy egret
(Collins and Foin 1993; Granholm 1987a; 1987b). The loss of habitat for
the Suisun song sparrow is of particular concern, since individuals of
this species are found only in the already fragmented marshes bordering
Suisun Bay, occupy an established territory for their lifetime, and
depend on tall tules for successful reproduction and cover from
predators (Marshall 1948).
There are currently no salinity criteria protecting the brackish
tidal marshes of Suisun Bay, although there is some incidental
protection provided by salinity criteria protecting the managed non-
tidal marshes. EPA's approval of the 1978 Delta Plan criteria
explicitly sought and received assurances from the State Board to
develop additional criteria for the brackish tidal marshes and to
protect aquatic life in the Suisun Marsh channels and open waters.
Because these assurances have not been met, EPA, in its September 3,
1991 letter on the 1991 Bay/Delta Plan, disapproved the standards for
Suisun Marsh and stated that the State Board should immediately develop
salinity objectives sufficient to protect aquatic life and the brackish
tidal wetlands surrounding Suisun Marsh.
In its Proposed Rule, EPA relied on the Estuarine Habitat criteria
to protect the tidal wetlands bordering Suisun Bay, and did not propose
separate standards in the Suisun Marsh. EPA's proposed criteria were
developed to protect aquatic species and to provide salinity conditions
similar to those in the late 1960's to early 1970's. Therefore, many of
the aquatic species that inhabit the marsh channels would receive
increased protection once the Estuarine Habitat criteria are
implemented. In addition, the Estuarine Habitat criteria were designed
to provide substantially better dry and critically dry year springtime
conditions than the recent conditions that have caused adverse effects
on the tidal marsh communities bordering Suisun Bay. EPA therefore
concluded that these Estuarine Habitat criteria would lead to
substantially improved conditions in the marshes.
In its Proposed Rule, EPA solicited comment as to whether the
Estuarine Habitat criteria should be supplemented by additional
criteria to fully protect the tidal marsh resources. For illustrative
purposes, EPA included two possible narrative criteria in the Proposed
Rule:
(1) ``water quality conditions sufficient to support high plant
diversity and diverse wildlife habitat throughout all elevations of the
tidal marshes bordering Suisun Bay''
(2) ``water quality conditions sufficient to assure survival and
growth of brackish marsh plants dependent on soils low in salt content
(especially Scirpus californicus and Scirpus acutus) in sufficient
numbers to support Suisun song sparrow habitat in shoreline marshes and
interior marsh channel margins bordering Suisun Bay.''
EPA received a number of substantive comments on this issue. The
State Board and the California DWR opposed additional criteria,
believing that any such criteria would be premature pending completion
of a biological assessment in the marsh (SWRCB 1994; California DWR
1994). The California DFG recommended adoption of the numeric salinity
criteria included in the Suisun Marsh Preservation Agreement signed by
California DFG, California DWR, the USBR, and the Suisun Resource
Conservation District in 1987 (California DFG 1994). Two environmental
organizations, Natural Heritage Institute and the Bay Institute,
recommended that additional standards be developed for the Suisun
Marsh. Relying primarily on scientific studies that had been prepared
and submitted to the State Board's D-1630 hearings (Jocelyn 1992,
WRINT-NHI-12; Williams 1992, WRINT-NHI-18), these groups raised
questions about whether the EPA Estuarine Habitat criteria would
adequately protect the brackish marshes during January and February, or
during a multiple year drought, and whether the Estuarine Habitat
criteria would adequately protect the interior tidal channels of Suisun
Marsh. In its comments, NHI recommended the adoption of numeric
salinity criteria (NHI 1994). The Bay Institute recommended adoption of
narrative criteria for the Marsh, and offered a detailed suggestion.
EPA believes that the available scientific information points
strongly to the need for numeric criteria in the tidal marshes.
Nevertheless, EPA does not believe there exists a sufficient scientific
basis at this time to support Federal promulgation of numeric criteria
for these marshes. EPA is hopeful that the biological studies being
prepared at the request of the State Board will be completed soon, and
that the State Board will expedite its review of this issue. Given the
substantial delays in the completion of these studies, however, EPA
does not believe it advisable to delay addressing the serious
possibility of adverse impacts to the brackish tidal marshes. For these
reasons, EPA is incorporating a narrative criterion applicable to the
tidal (i.e., unmanaged) areas of the Suisun Marsh in the final rule.
To be consistent with EPA guidance, narrative criteria should
include specific language about conditions that must exist to protect a
designated use, and may include specific classes and species of
organisms that will occur in waters for a given designation (USEPA
1990). The narrative criterion promulgated below by EPA includes
language about important measures of biological integrity specific to
Suisun Bay tidal marshes. Specific reference conditions are not
included in the criterion; however, it is the intent of this criterion
to reflect conditions equalling the level of protection existing in the
Suisun Marsh in the late 1960's to early 1970's. As a result of the
recent drought and continued high level of freshwater diversion from
the estuary, recent conditions have deteriorated in the Suisun Marsh,
as indicated by decreased habitat for the Suisun song sparrow and
replacement of tules with Spartina foliosa.
In implementing this narrative criterion, the State Board should
take care to protect the specific classes and species of organisms that
are vulnerable to increasing salinity in the Suisun Marsh. Vulnerable
species include those species that are presently listed under the
Federal Endangered Species Act, including the salt-marsh harvest mouse
(Reithrodontomys raviventris) and the California clapper rail (Rallus
longirostris obsoletus). Vulnerable species also include both those
rare plants that are candidates for listing under the Federal
Endangered Species Act (including Mason's lilaeopsis (Lilaeopsis
masonii), delta tule pea (Lathyrus jepsonii), Suisun slough thistle
(Cirsium hydrophilum var. hydrophilum), Suisun aster (Aster chilensis
var. lentus), soft-haired bird's beak (Cordylanthus mollis ssp mollis))
and dominant plant species such as the tules Scirpus acutus and S.
californicus, and the bulrush S. robustus. Animal species include
Federal candidate species Suisun song sparrow (Melospiza melodia
maxillaris), California black rail (Laterallus jamaicensis
coturniculus), tri-colored blackbird (Agelaius tricolor), saltmarsh
common yellowthroat (Geothylpis trichos sinuosa), Suisun
[[Page 4700]] ornate shrew (Sorex ornatus sinuosus) and southwestern
pond turtle (Clemmys marmorata pallida). Other vulnerable species
include river otter (Lutra canadensis), beaver (Castor canadensis),
nesting snowy egret (Egretta thula), nesting black-crowned night-heron
(Nycticorax ncyticorax), ducklings of breeding ducks such as mallard
(Anas platyrhynchos), gadwall (Anas strepera) and cinnamon teal (Anas
cyanoptera), marsh wren (Cistothorus palustris), American bittern
(Botaurus lentiginosus), Virginia rail (Rallus limicola), sora (Porzana
carolina), and common moorhen (Gallinula chloropus).
EPA hopes that the measures taken to implement the Estuarine
Habitat criteria will be sufficient to protect the fish and wildlife
designated uses targeted by this narrative criterion. Nevertheless, in
the event that continuing substantial adverse impacts on the brackish
marsh habitat become evident before any possible revisions to the
State's numeric criteria, this narrative criterion will provide a basis
for State Board measures to address those adverse impacts.
D. Public Comments
Public hearings on the Proposed Rule were held in Fresno,
California on February 23, 1994; in Sacramento, California on February
24, 1994; in San Francisco, California on February 25, 1994; and in Los
Angeles, California on February 28, 1994. Over 120 people spoke at
these four hearings. The public comment period closed on March 11,
1994. EPA received over 225 written comments on the Proposed Rule.\44\
\44\The Bay Institute submitted identical comment letters
generally supporting adoption of protective standards in the Bay/
Delta from approximately 1,500 people. The total number of comments
stated in the text counts these comments as a single comment.
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Responses to the public comments have been prepared and are a part
of the administrative record to this rulemaking. The public may inspect
this administrative record at the place and time described above.
E. Executive Order 12866
Under Executive Order 12866 (58 FR 51735, October 4, 1993), the
Agency must determine whether the regulatory action is ``significant''
and therefore subject to Office of Management and Budget (OMB) review
and the requirements of the Executive Order. The Order defines
``significant regulatory action'' as one that is likely to result in a
rule that may:
(1) Have an annual effect on the economy of $100 million or more or
adversely affect in a material way the economy, a sector of the
economy, productivity, competition, jobs, the environment, public
health or safety, or State, local, or tribal governments or
communities;
(2) Create a serious inconsistency or otherwise interfere with an
action taken or planned by another agency;
(3) Materially alter the budgetary impact of entitlements, grants,
user fees, or loan programs or the rights and obligations of recipients
thereof; or
(4) Raise novel legal or policy issues arising out of legal
mandates, the President's priorities, or the principles set forth in
the Executive Order.
Pursuant to the terms of Executive Order 12866, it has been
determined that this rule is a ``significant regulatory action''
because it raises novel policy issues arising out of the Federal
coordination effort described above. This coordination effort, which
calls for the integration of several Federal agencies and several
different Federal statutes, is a unique and precedential approach to
the implementation of Federal natural resources policy. As such, this
action was submitted to OMB for review. Changes made in response to OMB
suggestions or recommendations will be documented in the public record.
The following is a summary of the regulatory impact assessment
(RIA) that has been prepared in compliance with Executive Order 12866.
The full RIA is part of the administrative record to this rule, and is
available for public review as described above.
Executive Order 12866 requires Federal agencies to assess the costs
and benefits of each significant regulatory action they promulgate. The
RIA addresses two interrelated regulatory actions. The first is the
promulgation by EPA of water quality criteria for the Bay/Delta estuary
under the CWA. The second is the USFWS designation of critical habitat
for the Delta smelt under the ESA.
Need for Regulation
The Bay/Delta is the largest estuarine environment on the west
coast of the Americas, encompassing 1,600 square miles and draining
more than 40% of the water in California.
The Bay/Delta estuary supports more than 120 species of
fish and is a waterfowl migration and wintering area of international
significance.
The estuary supports 108 known species of fish, birds,
mammals, reptiles, amphibians, invertebrates, and plants imperiled by
habitat loss, including 25 species that are listed or are candidates
for listing under the Endangered Species Act (ESA).
The estuary is composed of numerous habitats valued for
their recreational, scientific, educational, aesthetic, and ecological
aspects; designated uses defined by the California State Water
Resources Control Board include estuarine habitat, coldwater and
warmwater habitat, fish migration, fish spawning, ocean commercial and
sport fishing, preservation of rare and endangered species, shellfish
harvesting, and wildlife habitat.
As a result of habitat change and other human-induced
impacts, the estuary's ability to support a diverse ecosystem with
large populations of important commercial, recreational, and heritage
species has declined. The 1980's and 1990's brought the number of
indigenous species to extremely low levels. Declines in aquatic
resources have led to curtailed fishing seasons, petitions for listing
species under the ESA, and general concern about the health of the
estuarine ecosystem.
The principal benefit expected to result from this
rulemaking is an increase in ecosystem health. A healthy Bay/Delta
ecosystem will maintain aquatic species in populations of sufficient
sizes to sustain recreational and commercial fisheries, as well as the
uniqueness and diversity still present in the estuary.
The Bay/Delta estuary is also the hub of California's two major
water distribution systems, the SWP operated by California DWR and the
CVP operated by the USBR. Most of the water stored and transported by
the CVP is used for agriculture; the CVP also supplies municipal and
industrial water to portions of the Central Valley and San Francisco
Bay Area. SWP water is primarily used for municipal and industrial uses
and the production of agricultural crops. Development and operation of
the water projects have contributed to losses in biological
productivity in the Bay/Delta estuary by substantially altering the
flow and salinity conditions to which the indigenous organisms are
adapted.
The Bay/Delta estuary is subject to the water quality control
jurisdiction of the State Board and two regional boards. Pursuant to
requirements of the CWA, the State Board in 1991 adopted and submitted
to EPA the 1991 Bay/Delta Plan containing water quality standards for
the Bay/Delta estuary. EPA, finding that the 1991 plan did not provide
for adequate protection of the designated fish and wildlife uses of the
Bay/Delta estuary, disapproved provisions of the plan. In response to
State Board's failure to revise the disapproved criteria, EPA published
the proposed rule for [[Page 4701]] establishing revised water quality
criteria; these EPA criteria are the primary subject of the RIA.
Approach
The RIA analyzes a final rule that establishes four sets of federal
criteria to protect the designated uses of the Bay/Delta estuary. The
analysis focuses on the two sets of criteria with measurable water
costs to Delta exporters:
Salinity criteria protecting the estuarine habitat, and
Fish migration criteria to protect fish migration in the
estuary.
The other two criteria; salinity criteria to protect fish-spawning
habitat on the lower San Joaquin river and narrative criteria to
protect tidal wetlands surrounding Suisun Marsh, are not expected to
result in actions that generate additional economic costs.
The primary method for implementing the criteria is to increase
Delta outflow, and the analysis focuses on the effects of this
approach. EPA recognizes that the State of California has sole
authority to reallocate water rights in implementing these criteria.
However, because the State has not yet developed a plan for
implementation of the criteria, EPA considered the water supply and
delivery impacts of the criteria using the following three
implementation approaches that represent the range of options available
to the State:
Project Exporters-Only Approach:
--Generally represents implementation of D-1485, under which the
SWP and CVP exporters are solely responsible for providing sufficient
water supplies to attain the water quality criteria.
--Because of priority systems within the SWP and CVP, would
concentrate responsibility for meeting the standards on water districts
with junior water rights, which also bear responsibility for meeting
requirements associated with the ESA. Municipal and industrial (M&I)
users are priority users within the SWP system. In the CVP priority
system, users of 27% of diversions are responsible for meeting 100% of
the ESA requirements and water quality standards.
--Could result in effects on San Joaquin Valley agricultural water
users, primarily in western Fresno and portions of Kern County and the
urban areas supplied by Metropolitan Water District of Southern
California (MWD) and Santa Clara Valley Water District (SCVWD).
Sharing Approach:
--Would spread water supply impacts to more or potentially all of
the water districts that divert water from the Sacramento and San
Joaquin River systems, including areas of the Sacramento Valley,
eastside San Joaquin Valley and urban areas of San Francisco and East
Bay.
--Could be based on formulas using many criteria in assigning
responsibility, such as diversions, depletions, damage caused by
diversions, seniority and priority of water rights, beneficial and
reasonable use, and economics.
--For the analysis, an illustrative formula was used where
nonproject diverters and non-exporter CVP users share 20% of
responsibility for meeting flow requirements necessary to achieve
compliance with the criteria.
Other Innovative Approaches:
--Could include combining shared implementation responsibility with
a system of mitigation credits, a water supply cap, and a fund or fee
system for purchasing water for environmental uses; policies for
promoting a water market and/or a water bank are crucial.
Water Supply and Delivery Impacts
Short-term (1995) and longer term (2010) impacts of the Project
Exporters-Only and Sharing Approaches were analyzed through comparison
with baseline conditions consisting of current conditions that exist in
the absence of the criteria, estimated for a range of hydrological
conditions represented in the 71-year hydrologic record for the Delta.
Water supply costs are commonly reported using two conventions: the
average of 71 years and the ``critical period'', which represents
conditions experienced in the drought period of the 1930s.
The analysis estimated the incremental (i.e. new) water supply and
delivery impacts of the criteria over those associated with D-1485 and
the recent (1992-1994) winter-run salmon requirements. These impacts
reflect the effects of a package of federal actions under several laws
designed to comprehensively protect the Bay/Delta ecosystem. The entire
package of actions and requirements have been extensively coordinated
to achieve significant improvements in the Bay/Delta ecosystem.
Both the incremental water supply impacts, as well as the recent
Endangered Species Act impacts can be illustrated in the following
table:
BILLING CODE 6560-50-P
[[Page 4702]]
[GRAPHIC][TIFF OMITTED]TR24JA95.010
BILLING CODE 6560-50-C
[[Page 4703]]
Water delivery impacts are the changes in water volumes available
to different users and depend on seniority of water rights and priority
systems within affected water delivery systems, such as the SWP and the
CVP.
Costs
The State's implementation plan will substantially affect the
magnitude and distribution of the costs of regulatory actions. In the
agricultural sector, economic welfare costs would consist primarily of
changes in producers' surplus (net operating revenues accruing to
farmers). In the urban sector, economic welfare costs would take the
form of consumers' surplus losses to the residential sector resulting
from developing higher cost replacement supplies and consumer costs of
water supply shortages. The following are key results of the cost
analysis:
Water transfers can greatly reduce impacts on affected
agricultural and urban areas. Water transfers to urban areas through
waterbank programs are common and considered likely in the short-run.
Although, increased agriculture-to-agriculture water transfers are not
expected in the short-run, they can theoretically decrease impacts
considerably.
Urban project contractors water supplies would not be
affected in most years, even without sharing.
--MWD's supplies are affected in 11% of years, SCVWD supplies are
affected in 25% of years.
With water transfers available in dry years, the cost
associated with the regulations is estimated to be $4.3 million on
average and $15.8 million during dry water years for the Project-
Exporters Only scenario. Without water transfers or waterbanks, costs
increase significantly; the combined cost of water shortages and
replacement water supplies to project users is estimated to be $28.3
million on average years and $165.3 million during dry years.
Agricultural impacts would be small relative to
agricultural value in the Central Valley but would be concentrated in
agricultural areas with low-seniority water rights in portions of
Fresno and Kern counties.
--Under the Project-Exporters Only scenario and assuming no
increase in water transfers, economic welfare losses to agriculture are
estimated to average $27 million annually, weighted over all
hydrological conditions. However, impacts in the driest 10% of years
account for economic costs of $43 million.
--If the State's implementation plan is based solely on seniority
of water rights and existing contractual arrangements, impacts will be
concentrated in geographic subareas of Fresno and Kern counties.
Cumulative impacts are an important consideration in these areas--the
impacts of environmental requirements associated with the ESA and the
CVPIA are already concentrated in these subareas. However, the State's
implementation plan may be based on many criteria, including economics.
The Sharing Approach would have an important cost-reducing
effect, especially in dry years if transfers are limited, in comparison
with the Project Exporters-Only Approach.
--Economic welfare costs to agriculture would be reduced by sharing
the responsibility of environmental requirements with all diverters.
Overall, economic welfare losses would be reduced by approximately $0.5
million for average years and more than $5.5 million in dry years.
--A net gain in economic welfare to urban areas would also result
from sharing. Overall economic losses would be reduced by approximately
$10.5 million in average years and $54.0 million in dry years when
transfers are limited.
Over the long term, costs are not estimated to
substantially increase, even with increasing demand resulting from
population growth and decreased groundwater availability.
A summary of these costs is shown below in RIA Table 2.
RIA Table 2.--Summary of Economic Welfare Costs
[In millions of dollars]
------------------------------------------------------------------------
Average
expected Dry
value Years
------------------------------------------------------------------------
Agriculture:\1\
No increase in water transfers............ 28 43
Sharing/no increase in transfers.......... 27 37
Increased transfers....................... 10-18 NA
Urban:\2\
Dry year transfer......................... 4 16
No dry year transfer...................... 28 165
Sharing/no dry year transfer.............. 18 111
------------------------------------------------------------------------
Note: Total impacts are less than the sum of agricultural and urban
impacts in the case of agricultural-to-urban transfers. In cases in
which there are no agricultural-to-urban transfer, total impacts equal
the sum of agricultural and urban impacts.
\1\Transfers are from agriculture to agriculture.
\2\Transfers are from agriculture to urban users.
Benefits
Important benefits of the water quality regulations include the
following:
Biological productivity and health for many estuarine
species are expected to increase.
The decline of species is expected to be reversed and the
existence of species unique to the Bay/Delta, such as Delta smelt,
winter-run chinook salmon, longfin smelt, and Sacramento splittail,
will be protected.
Populations of a variety of estuarine species are expected
to increase; although the extent of the population increases has not
been determined for all species, the increases are anticipated to
benefit the recreational and commercial fisheries.
Costs associated with further declines in the estuary will
be avoided. The most important avoided cost is associated with further
declines in the recreational and commercial fisheries industry
including further closures affecting the 200 million dollar industry,
with possible future actions needed to protect species from extinction.
Other avoided costs include government costs associated with crop
deficiency payments; agricultural drainage costs; and costs associated
with potential reductions in property values.
The ecological benefits of improved Bay/Delta estuary conditions
are expected to generate approximately $2-21 million annually in net
economic benefits to commercial and recreational fisheries and have
associated employment gains of an estimated 145-1,585 full-time
equivalent jobs annually. The federal package of actions to protect the
estuary, of which EPA's criteria are a part, will also produce the
benefit of increased certainty regarding water supplies from the delta;
this allows for more informed water management planning and
investments.
Conclusions
The following general conclusions can be drawn regarding the
results of the RIA:
Although urban water supplies are are not affected in most
years, however, minimizing urban costs largely depend on the
availability of water through transfers and a drought water bank.
Under the Project-Exporters Only approach to
implementation (i.e., status-quo), agricultural impacts are
concentrated only in certain areas of Fresno and Kern Counties. This
concentration of impacts is magnified by these areas bearing the
responsibility for Endangered Species requirements. This concentration
of impacts is the [[Page 4704]] result of historic water rights
arrangements and may be attenuated through the water rights phase.
Benefits of ecosystem protection, which could not be
estimated in the analysis, are expected to substantially exceed the use
benefits to commercial and recreational fisheries. These nonuse or
intrinsic values, which include benefits to the public for improved
ecosystem health and for avoiding the extinction of species and
closures of fisheries, are difficult to estimate accurately because
they are nonmarginal.
Substantial reductions in economic costs--for the same
level of benefits--resulted from the sharing scenario analysis,
particularly when transfers are limited. For urban areas, the economic
benefits of dry year transfers are large, even when compared to the
benefits of sharing.
Although a fully developed water market is not likely, it
could theoretically reduce economic costs to very low levels.
Innovative implementation plans (purchase funds, fees, tradeable
responsibility) that take advantage of these potential efficiencies may
be the most cost-effective solution.
Given both the monetary estimates and the information on ecological
benefits that is not calculated in monetary terms, EPA believes that
the benefits are commensurate with the costs. Cost-effective
implementation of the criteria will result in a healthy ecosystem and
fisheries resources coexisting with a strong agricultural sector.
F. Regulatory Flexibility Act
Under the Regulatory Flexibility Act (5 U.S.C. 601 et seq.) (RFA)
EPA generally is required to conduct a final regulatory flexibility
analysis (FRFA) describing the impact of the regulatory action on small
entities as part of a final rulemaking. However, under section 605(b)
of the RFA, if EPA certifies that the rule will not have a significant
economic impact on a substantial number of small entities, EPA is not
required to prepare a FRFA. Although EPA is providing the certification
here, it is nevertheless including a discussion for public information
of possible effects to small entities that could result from State
Board implementation of today's rule.
Today's rule establishes ambient water quality criteria that are
unique in that implementation of these criteria is solely dependent
upon actions by agencies other than EPA. Until actions are taken to
implement today's criteria (or equally protective state criteria
meeting the requirements of the CWA), there will be no economic effect
of this rule on any entities--large or small. For that reason, and
pursuant to section 605(b) of the Regulatory Flexibility Act, 5 U.S.C.
605(b), I hereby certify that this rule itself will not have a
significant economic impact on a substantial number of small entities.
Discussion
Although EPA is certifying that this rule will not have a
significant economic impact on a substantial number of small entities,
and therefore is not required to prepare a FRFA, it is nevertheless
presenting this discussion to inform the public of possible economic
effects of state implementation of the criteria promulgated today on
small entities. By so doing, EPA intends to inform the public about how
such entities might be affected by the State's implementation. The
focus of the discussion is on small farms, and our analysis shows that
there will be no significant economic effect on a substantial number of
them. Additionally, as described elsewhere in the RIA, impacts on the
urban sector, while speculative, are expected to be limited.
Accordingly, EPA believes there will be no significant economic impact
on a substantial number of small entities as a result of the State's
implementation of these criteria.
This discussion first provides a profile of small entities--in this
case small farms--to determine whether or not they will be affected by
State Board actions designed to attain the criteria set forth in this
rulemaking. EPA investigated information by geographic area using the
U.S. Small Business Administration's definition. Information used
includes acreage and gross value per acre.
Small entities that may be primarily affected by the State's
implementation of EPA's rule are small farms (as discussed in the RIA,
the primary economic impacts of implementation of these criteria are
expected to fall on the agricultural sector; impacts on the urban
sector are expected to be limited). Small farms are defined by the U.S.
Small Business Administration as farms with annual sales of less than
$500,000. Small farms account for 93% of all farms and 53% of all
cropland (including unharvested pastureland) in California. The
remaining 7% of California farms, which have annual sales of more than
$500,000, account for 74% of the value of farm products sold (Jolly
1993). Unfortunately, no survey information is available by
subgeographic area and value per operator to assist in determining
whether or not State Board action implementing this rulemaking could
affect small farms. As discussed in the RIA, impacts may be
concentrated in the subgeographic areas of the San Joaquin Valley--
particularly the westside of Fresno County, including Westlands Water
District and Kern County. This analysis uses the worst case scenarios
from the RIA in assuming concentrated and, possibly, not insignificant
impacts in these areas. These assumptions include: no increase in water
transfers and the most status-quo implementation plan selected by the
State of California. As discussed in the RIA, innovative implementation
plans could reduce all agricultural impacts.
Due to the lack of survey information, two commonly reported
measures--gross value per acre and acreage per farm--were used to
develop an indication of whether or not these subgeographic areas
contain small farms, by the SBA definition. The first commonly reported
indicator of farm size is acreage.
EPA used two measures of farm size by acreage in the San Joaquin
Valley, derived from the 1987 Census of Agriculture. The first measure,
average farmland per operator, includes the average amounts of
cropland; rangeland; wooded lands; and lands in buildings, roads, and
ponds managed by each farm operator in the San Joaquin Valley. The
average amount of farmland per operator in the San Joaquin Valley is
341 acres, varying from 266 acres in non-westside areas to 1,834 acres
in the Westlands Water District. The second measure of farm size,
irrigated land per operator, includes the average amount of cropland,
excluding rangelands and wooded lands, managed by each farm operator.
The average amount of irrigated land per operator in the San Joaquin
Valley is 165 acres, ranging from 114 acres in non-westside areas to
1,113 acres in the Westlands Water District. These data suggest that
some agricultural districts contain very few small farms, while others
are largely composed of smaller farms.
These measures of farm size may be distorted by characteristics of
the data compiled in the 1987 Census of Agriculture. Because of the way
farm operators are defined and counted within the census, the number of
truly separate farm operations within the San Joaquin Valley may be
lower than the census reports. Thus, the amount of farmland and
irrigated land per separate farm operation is probably higher than
reported. Additionally, farming is not the principal occupation for
many farm operators. In the San Joaquin Valley, 44% of the operators
included in the census reported that farming was not
[[Page 4705]] their principal occupation (Archibald 1990). These
operations, which could include hobby farms, are probably much smaller
than commercial operations. Therefore, the average size of commercial
operations is likely much larger than reported. These data limitations
make it difficult to assess the true proportion of the farm industry
represented by small commercial farms.
The other measure used to develop an indication of whether or not
small farms are affected is average gross revenue per acre. This
information was obtained from the USBR and the same data is used in the
RIA. As discussed previously, the areas where impacts may be
concentrated are primarily the westside of the San Joaquin Valley,
especially Westlands Water District and Kern County. Values of $1100-
$2300 an acre are indicated by this data. These estimates are further
confirmed by the average value of $1413 an acre found in a recent
University of California report (Carter 1992.) Thus using the range of
values for gross revenue per acre and the more conservative definition
of irrigated land per acre for the Westside, farms average
approximately $600,000 -$1,120,000. This does not meet the SBA
definition. In addition, average farm size in the Westlands Water
District is much larger, leading to average estimates over $1 million
per operator. In Kern County, however, gross revenue per acre averages
$1863 and therefore to meet the SBA definition a farm would have to be
unusually small (under 270 acres.) These estimates indicate that a
substantial number of small entities would not be substantially
affected.
The farms in the CVP area (westside Fresno County) are subject to
the U.S. Department of Interior 960-acre limitation on farm size for
the receipt of subsidized water. Although the degree of compliance with
this limitation is in question, a recent legal settlement by the U.S.
Department of Interior will increase the enforcement of this acreage
limitation. Using the measures of average gross revenue per acre, farms
that approach the acreage limitation are not considered small farms
using the SBA definition.
Type of small farm by crop type was also investigated to provide
another indication of farms potentially affected by State Board action.
As discussed in the RIA, State Board action consistent with this
rulemaking would likely result primarily in field and forage crop
displacement. In 1987, small farms produced 40% of all irrigated hay
and field crops harvested and 30% of all nonfeedlot cattle sales in the
state (U.S. Dept. of Commerce 1989). Approximately 80% of the irrigated
hay and field crops and 50% of nonfeedlot cattle are raised in the
Sacramento Valley and San Joaquin Valley counties (U.S. Dept. of
Commerce 1989). Such cattle production is the principal use of
irrigated pasture in California. These percentages are substantially
lower than the overall percentage of cropland in small farms. In other
words, large farms (i.e., farms with annual sales exceeding $500,000)
account for a disproportionate share of the production of the crops and
livestock that might be displaced by the projected water supply
reductions.
While these measures indicate that the State's implementation of
the criteria in this rule will not affect a substantial number of small
farms, given that the measure was developed from averages, there will
exist in every irrigation district some small farms. Westlands Water
District reports that 125 farms are 320 acres or less (a 320 acre farm
grossing $1400-$1500 an acre would meet the SBA definition of a small
farm.) Thus, without survey information, we cannot completely conclude
that all small farms would not be affected by State Board action.
The RIA conducted for this rulemaking indicates that if previous
implementation procedures are followed, impacts may be concentrated in
geographic subareas. The State does have implementation flexibility to
spread the impacts to a greater geographic area. This would have two
offsetting impacts in relationship to farm size. First, the impacts
overall will be decreased so that impacts would be less concentrated in
subregions, possibly to insignificant levels. Second, however, in
spreading the impacts more broadly, the State will be spreading it to
areas with small farms.
Within irrigation districts with project water, junior water rights
and little access to groundwater, even the State may have little
implementation authority to assess or minimize impacts by farm size. A
Stanford University study explains:
Most farmers receive their water from a local district (generally
an irrigation, water, or water storage district) or from a mutual water
company * * * local districts have considerable discretion over the
acquisition, allocation and pricing of water. The nature and limits of
the discretion, however, vary among districts depending on the laws
under which the district was formed, any special legislation unique to
a district, and a district's local rules and regulations. (Center for
Economic Policy Research 1992.)
G. Enhancing the Intergovernmental Partnership Under Executive
Order 12875
In compliance with Executive Order 12875, 58 FR 58093 (October 28,
1993), we have involved state, local, and tribal governments in the
development of this rule. In addition to the substantial participation
by state and local governments and local agricultural and municipal
water districts in the public commenting process, several activities
have been carried out since the publication of the Proposed Rule. These
include:
(1) The State of California and the Federal government (represented
by the EPA, the Department of the Interior, and the Department of
Commerce) have negotiated and this past summer signed a Framework
Agreement laying out the institutional processes and mechanisms to be
used to coordinate state and Federal activities affecting water quality
and water development in the Bay/Delta. The Framework Agreement
specifically included (a) a process for Federal and state adoption of
water quality standards meeting the requirements of state and Federal
law, (b) a structure and process for technical coordination of the
state and Federal regulatory activities affecting operation of the
state and Federal water projects in the Bay/Delta (the SWP and the
CVP), and (c) a process for developing a Federal-state partnership for
long term planning for water resources in California. Many of the steps
envisioned in the Framework Agreement have already been accomplished.
The Framework Agreement explicitly called for the final Federal
promulgation of a water quality rule, which is being accomplished in
this rulemaking.
(2) EPA has held a number of workshops with representatives of the
municipal and agricultural water districts to discuss the Proposed Rule
and the accompanying draft economic analysis. Further, EPA has
participated in additional workshops sponsored by the California Urban
Water Agencies (CUWA) to discuss CUWA's scientific comments on the
Proposed Rule.
(3) As envisioned by the Framework Agreement, the State Board has
held a series of workshops to assist in developing revised State water
quality standards meeting the requirements of the CWA. EPA has
participated in these workshops and, in accordance with the State
Board's processes, has presented the State Board options for possible
standards that would meet the requirements of the CWA.
(4) EPA has worked closely with the California DWR to ascertain the
[[Page 4706]] probable water supply impacts of its Proposed Rule, and
has continued to work with California DWR to explore mechanisms for
reducing water supply impacts of protective standards. As explained in
the Preamble to the final rule, many of these mechanisms have been
incorporated into EPA's final rule.
(5) EPA has worked closely with representatives of a coalition of
CUWA and of agricultural water agencies to consider alternative
standards and measures that would meet the requirements of the CWA.
(6) EPA has continued to meet with the State Board and other State
officials, both at the staff and policy levels, to discuss ways to
attain protection of the Bay/Delta resources in a way that meets the
requirements of the CWA and is consistent with the State's roles in
water quality and water development planning.
H. Paperwork Reduction Act
This rule places no information collection activities on the State
of California and, therefore, no information collection request (ICR)
will be submitted to the Office of Management and Budget (OMB) for
review in compliance with the Paperwork Reduction Act, 44 U.S.C. 3501
et seq.
References in the Preamble
Archibald, S. 1990. Economic profile of agriculture in the west
side of the San Joaquin Valley.
Arthur, J.F., and M.D. Ball, 1979. Factors influencing the
entrapment of suspended materials in the San Francisco Bay/Delta
Estuary. In: San Francisco Bay: The Urbanized Estuary, R.J. Conomos
(ed.). Pacific Div., American Assoc. for the Advancement of Science,
San Francisco, California, pp. 143-174.
Association of California Water Agencies, 1994. Comments of the
Association of California Water Agencies on water quality standards
for the Bay/Delta dated July 13, 1994. 22 pp.
Bay Institute, 1994. Comments on the proposed Rule for Water
Quality Standards in the Bay/Delta, 1 p., plus three appendices and
three enclosures.
Bay/Delta Urban Coalition, 1994. Letter from Steering Committee
to P. Wright dated March 4, 1994. 4 pp., plus large comment book.
Brandes, P., 1994. Development of a Refined San Joaquin Delta
Salmon Smolt Model. Draft Report, May 31, 1994. 7 pp. plus
attachments.
California Department of Fish and Game, 1990a. Central Valley
Salmon and Steelhead Restoration and Enhancement Plan. 115 pp.
California Department of Fish and Game, 1990b. Testimony of
Department for Fish and Game. WQCP-DFG-4.
California Department of Fish and Game, 1992a. Water quality and
water quantity needs for chinook salmon production in the Upper
Sacramento River. Prepared for the California SWRCB Interim Water
Rights Decision on the San Francisco Bay/Sacramento-San Joaquin
Delta Estuary. WRINT-DFG-14.
California Department of Fish and Game, 1992b. Summary and
Recommendations for the Department of Fish and Game's Testimony on
the Sacramento-San Joaquin Estuary. WRINT-DFG-8.
California Department of Fish and Game, 1994. Comments on the
Water Quality Standards for the Bay and Delta, 6 pp., plus 1 p.
comment attachment.
California Department of Water Resources, 1993. Biological
Assessment for South Delta Temporary Barriers Project for USFWS
Section 7 Endangered Species Permit. Amendment 1. Office of
Environmental Services. March 1993. 35 pp.
California Department of Water Resources, 1994. Comments on the
Water Quality Standards for the Bay and Delta, 2 pp., plus 88+ pp.
comment booklet and 7 appendices.
California Farm Bureau Federation, 1994. Letter from B. Vice to
C. Browner dated April 8, 1994. 2 pp., plus attachments.
California State Lands Commission, 1991. Delta-Estuary:
California's Inland Coast, A Public Trust Report, 208 pp.
California Urban Water Agencies, 1994a. Comments on the Water
Quality Standards for the Bay and Delta dated March 9, 1994. 3 pp.,
plus 5 pp. supplementary comments and 12 draft technical appendices.
California Urban Water Agencies, 1994b. Recommendations to the
State Water Resources Control Board for a coordinated estuarine
protection program for the San Francisco Bay-Sacramento and San
Joaquin River Delta Estuary, August 25, 1994. 46 pp. plus 2
appendices.
Carter, H., and G. Goldman, 1992. The Measure of California
Agriculture. University of California. Oakland, California.
Center for Economic Policy Research, 1992. An Economic Analysis
of Water Availability in California Central Valley Agriculture,
Phase III Draft Report. Stanford, California.
City & County of San Francisco Public Utilities Commission,
1994. Letter from A. Moran to P. Wright dated March 11, 1994. 2 pp.,
plus attachments.
Collins, J.N. and T.C. Foin, 1993. Evaluations of the Impacts of
Aqueous Salinity on the Shoreline Vegetation of Tidal Marshlands in
the San Francisco Estuary. In: SFEP, Managing Freshwater Discharge
to the San Francisco Bay-Delta Estuary: The Scientific Basis for an
Estuarine Standard. Appendix C.
Contra Costa Water District, 1994. Comments on the Water Quality
Standards for the Bay and Delta, 5 pp., plus 2 attachments.
Denton, R.A., 1993. Accounting for Antecedent Conditions in
Seawater Intrusion Modeling--Applications for the San Francisco Bay/
Delta Hydraulic Engineering 93, vol. 1, pp. 448-453.
Denton, R.A., 1994. Minor Modifications to the G-Model Fit of
Electrical Conductivity Versus Antecedent Outflow. Internal CCWD
report, 8 pp.
Five Agency Delta Salmon Team, 1991a. Evaluation of the
Feasibility of Protecting Downstream Migrant Chinook Salmon Smolts
in the Sacramento River and San Joaquin River with Physical
Facilities, July 15, 1991.
Five Agency Delta Salmon Team, 1991b. Benefit/Cost Evaluations
of Alternative Salmon Protective Measures in the Sacramento-San
Joaquin Delta. Draft Report. March 13, 1991. 101 pp.
Farley, T.C., 1966. Striped bass, Roccus saxatilis, spawning in
the Sacramento San Joaquin River systems during 1963 and 1964. DFG
Fish Bull. 136 pages 28-43.
Ferriera, I. and H. Meyer, 1994. WRMI Presentation at the
Sliding Scale Workshop, April 14, 1994, 1 p.
Granholm, S.L., 1987a. Special-status wildlife species of the
Suisun Bay tidal marshes, and expected impacts of reduced freshwater
inflows. Sierra Club Legal Defense Fund Exhibit 4, SWRCB San
Francisco Bay/Delta Hearings.
Granholm, S.L., 1987b. Expected impacts of reduced freshwater
inflows on representative birds and mammals of the Suisun Bay tidal
marshes. Sierra Club Legal Defense Fund Exhibit 5, SWRCB San
Francisco Bay/Delta Hearings.
Harvey, T.E., K.J. Miller, R.L. Hothem, M.J. Rauzon, G.W. Page,
R.A. Keck, 1992. Status and Trends Report on Wildlife of the San
Francisco Estuary. January 1992.
Herbold, B., A.D. Jassby, P.B. Moyle, 1992. San Francisco
Estuary Project Status and Trends Report on Aquatic Resources in the
San Francisco Estuary. March 1992. 257 pp.
Jocelyn, M., 1992. Adverse effects of increased salinity in the
Suisun Marsh Brackish wetlands. WRINT-NHI-12. 6 pp.
Jolly, 1993. ``The small farm: It's innovative and persistent in
a changing world'', 47 California Agriculture No. 2. University of
California, Oakland, California.
Kimmerer, W., 1994a. A sliding scale for the EPA salinity
standard. 12 p.
Kimmerer, W., 1994b. Setting Goals for Salmon Smolt Survival in
the Delta and Discussions on the Proposed EPA Salinity Standard.
August 10, 1994. 28 pp.
Kjelson, M., S. Green & P. Brandes, 1989. A Model for Estimating
Mortality and Survival of Fall-run Chinook Salmon Smolts in the
Sacramento River Delta between Sacramento and Chipps Island.
Marshall, J.T., Jr., 1948. Ecologic races of song sparrows in
the San Francisco Bay region, Part I. Habitat and abundance. Condor
50(5) 193-215.
Meiorin, E.C., M.N. Josselyn, R. Crawford, J. Calloway, K.
Miller, R. Pratt, T. Richardson and R. Leidy, 1991. Status and
Trends Report on Wetlands and Related Habitats in the San Francisco
Estuary. San Francisco Estuary Project, December 1991.
Meng, L., 1994. Status Report on Sacramento splittail and
longfin smelt. Unpublished report submitted to USFWS August 25,
1994. 15 pp. plus attachments.
Monismith, S.J., 1993. A note on the physical significance of
X2. IESP Newsletter, June 1993.
Moyle, P.B. and R.M. Yoshiyama, 1992. Fishes, Aquatic Diversity
Management Areas, and Endangered Species: A Plan to Protect
California's Native Aquatic Biota. University of California.
California Policy Seminar Report. 222 pp. [[Page 4707]]
Natural Heritage Institute, 1994. Comments on the proposed rule
for water quality standards in the Bay/Delta, 1 p., plus 42+ pp. of
comments and Attachments A-F.
Radtke, L.D., 1966. Distribution and abundance of adult and
subadult striped bass Roccus saxatilis, in the Sacramento-San
Joaquin Delta. DFG Fish Bulletin 136 pages 15-27.
Radtke, L.D. and J.L. Turner, 1967. High concentrations of total
dissolved solids block spawning migration of striped bass, Roccus
saxatilis, in the San Joaquin River, California. Transactions of the
American Fisheries Society 96:405-407.
San Francisco Estuary Project, 1992. State of the Estuary: A
Report on Conditions and Problems in the San Francisco Bay/
Sacramento-San Joaquin Delta Estuary. 270 pp.
San Francisco Estuary Project, 1993. Managing Freshwater
Discharge to the San Francisco Bay/Sacramento-San Joaquin Delta
Estuary: The Scientific Basis for an Estuarine Standard. 17 pp. +
appendices.
San Joaquin Valley Drainage Program, 1990. A Management Plan for
Agricultural Subsurface Drainage and Related Problems on the
Westside San Joaquin Valley. 183 pp.
SWRCB, 1987. Phase I Hearing Transcript, Volume XLI, 68:1-69:10.
December 22, 1987.
SWRCB, 1988. Draft Water Quality Control Plan for Salinity, San
Francisco Bay/Sacramento-San Joaquin Delta Estuary. October 1988.
SWRCB, 1991. Water Quality Control Plan for Salinity, San
Francisco Bay/Sacramento-San Joaquin Delta Estuary. 91-15WR, May
1991.
SWRCB, 1994. Comments on the Water Quality Standards for the Bay
and Delta, 2 pp., plus 63+ pp. comments attachment.
Turner, J.L., 1972a. Striped bass spawning in the Sacramento and
San Joaquin Rivers in Central California. Calif. Fish Game 62:106-
118.
Turner, J.L., 1972b. Striped Bass in Ecological Studies of the
Sacramento-San Joaquin Delta Estuary, DFG Delta Fish and Wildlife
Protection Report 8 pages 36-43.
Turner, J.L. and H.K. Chadwick, 1972. Distribution and abundance
of young-of-year striped bass (Morone saxatilis) in relation to
river flow in the Sacramento-San Joaquin Estuary. Transactions
American Fisheries Society 101(3):442-452.
Turner, J.L. and T.C. Farley, 1971. Effects of temperature,
salinity, and dissolved oxygen on the survival of striped bass eggs
and larvae. Calif. Fish and Game 57:268-273.
U.S. Department of Commerce, 1989. 1987 Census of Agriculture,
Volume 1, Geographic Area Series, Part 5, California State and
County Data.
USEPA, 1990. Biological Criteria: National Program Guidance for
Surface Waters. EPA-440/5-90-004, April 1990.
USFWS, 1992a. Measures to improve the protection of chinook
salmon in the Sacramento/San Joaquin River Delta. WRINT-USFWS-7.
Expert testimony of U.S. Fish and Wildlife Service on chinook salmon
technical information for State Water Resources Control Board Water
Rights Phase of the Bay/Delta Proceedings, July 6, 1992.
USFWS, 1992b. Abundance and survival of juvenile chinook salmon
in the Sacramento-San Joaquin Estuary. WRINT-USFWS-9. 1991 Annual
Progress Report. Sacramento-San Joaquin Estuary Fishery Resource
Office, U.S. Fish and Wildlife Service, Stockton, Calif. June, 1992.
USFWS, 1992c. Expert testimony of United States Fish and
Wildlife Service on recommendations for interim protection and
response to hearing notice key issues for State Water Resources
Control Board Water Rights Phase of the Bay-Delta Estuary
Proceedings, July 6, 1992. WRINT-USFWS-8.
Williams, P., 1992. Management of Salinity in Suisun Bay. WRINT-
NHI-18. 3+ pp.
List of Subjects in 40 CFR Part 131
Environmental protection, Indians--lands, Intergovernmental
relations, Reporting and recordkeeping requirements, Water pollution
control, Water quality standards, Water quality criteria.
Dated: December 14, 1994.
Carol M. Browner,
Administrator.
40 CFR part 131 is amended as follows:
PART 131--[AMENDED]
1. The authority citation for part 131 continues to read as
follows:
Authority: 33 U.S.C. 1251 et seq.
2. Section 131.37 is added to read as follows:
Sec. 131.37 California.
(a) Additional criteria. The following criteria are applicable to
waters specified in the Water Quality Control Plan for Salinity for the
San Francisco Bay/Sacramento-San Joaquin Delta Estuary, adopted by the
California State Water Resources Control Board in State Board
Resolution No. 91-34 on May 1, 1991:
(1) Estuarine habitat criteria. (i) General rule. (A) Salinity
(measured at the surface) shall not exceed 2640 micromhos/centimeter
specific conductance at 25 deg.C (measured as a 14-day moving average)
at the Confluence of the Sacramento and San Joaquin Rivers throughout
the period each year from February 1 through June 30, and shall not
exceed 2640 micromhos/centimeter specific conductance at 25 deg.C
(measured as a 14-day moving average) at the specific locations noted
in Table 1 near Roe Island and Chipps Island for the number of days
each month in the February 1 to June 30 period computed by reference to
the following formula:
Number of days required in Month X = Total number of days in Month X *
(1-1/(1+eK)
where K = A + (B*natural logarithm of the previous month's 8-River
Index);
A and B are determined by reference to Table 1 for the Roe Island and
Chipps Island locations;
x is the calendar month in the February 1 to June 30 period;
and e is the base of the natural (or Napierian) logarithm.
Where the number of days computed in this equation in paragraph
(a)(1)(i)(A) of this section shall be rounded to the nearest whole
number of days. When the previous month's 8-River Index is less than
500,000 acre-feet, the number of days required for the current month
shall be zero.
Table 1. Constants applicable to each of the monthly equations to
determine monthly requirements described.
----------------------------------------------------------------------------------------------------------------
Chipps Island Roe Island (if triggered)
Month X ---------------------------------------------------------------
A B A B
----------------------------------------------------------------------------------------------------------------
Feb............................................. -\1\ -\1\ -14.36 +2.068
Mar............................................. -105.16 +15.943 -20.79 +2.741
Apr............................................. -47.17 +6.441 -28.73 +3.783
May............................................. -94.93 +13.662 -54.22 +6.571
June............................................ -81.00 +9.961 -92.584 +10.699
----------------------------------------------------------------------------------------------------------------
\1\Coefficients for A and B are not provided at Chipps Island for February, because the 2640 micromhos/cm
specific conductance criteria must be maintained at Chipps Island throughout February under all historical 8-
River Index values for January.
(B) The Roe Island criteria apply at the salinity measuring station
maintained by the U.S. Bureau of Reclamation at Port Chicago (km 64).
The Chipps Island criteria apply at the Mallard Slough Monitoring Site,
Station [[Page 4708]] D-10 (RKI RSAC-075) maintained by the California
Department of Water Resources. The Confluence criteria apply at the
Collinsville Continuous Monitoring Station C-2 (RKI RSAC-081)
maintained by the California Department of Water Resources.
(ii) Exception. The criteria at Roe Island shall be required for
any given month only if the 14-day moving average salinity at Roe
Island falls below 2640 micromhos/centimeter specific conductance on
any of the last 14 days of the previous month.
(2) Fish migration criteria. (i) General rule.
(A) Sacramento River. Measured Fish Migration criteria values for
the Sacramento River shall be at least the following:
At temperatures less than below 61 deg.F: SRFMC = 1.35
At temperatures between 61 deg.F and 72 deg.F: SRFMC = 6.96-.092 *
Fahrenheit temperature
At temperatures greater than 72 deg.F: SRFMC = 0.34
where SRFMC is the Sacramento River Fish Migration criteria value.
Temperature shall be the water temperature at release of tagged salmon
smolts into the Sacramento River at Miller Park.
(B) San Joaquin River. Measured Fish Migration criteria values on
the San Joaquin River shall be at least the following:
For years in which the SJVIndex is > 2.5: SJFMC = (-0.012) +
0.184*SJVIndex
In other years: SJFMC = 0.205 + 0.0975*SJVIndex
where SJFMC is the San Joaquin River Fish Migration criteria value, and
SJVIndex is the San Joaquin Valley Index in million acre feet (MAF)
(ii) Computing fish migration criteria values for Sacramento River.
In order to assess fish migration criteria values for the Sacramento
River, tagged fall-run salmon smolts will be released into the
Sacramento River at Miller Park and captured at Chipps Island, or
alternatively released at Miller Park and Port Chicago and recovered
from the ocean fishery, using the methodology described in this
paragraph (a)(2)(ii). An alternative methodology for computing fish
migration criteria values can be used so long as the revised
methodology is calibrated with the methodology described in this
paragraph (a)(2)(ii) so as to maintain the validity of the relative
index values. Sufficient releases shall be made each year to provide a
statistically reliable verification of compliance with the criteria.
These criteria will be considered attained when the sum of the
differences between the measured experimental value and the stated
criteria value (i.e., measured value minus stated value) for each
experimental release conducted over a three year period (the current
year and the previous two years) shall be greater than or equal to
zero. Fish for release are to be tagged at the hatchery with coded-wire
tags, and fin clipped. Approximately 50,000 to 100,000 fish of smolt
size (size greater than 75 mm) are released for each survival index
estimate, depending on expected mortality. As a control for the ocean
recovery survival index, one or two groups per season are released at
Benecia or Pt. Chicago. From each upstream release of tagged fish, fish
are to be caught over a period of one to two weeks at Chipps Island.
Daylight sampling at Chipps Island with a 9.1 by 7.9 m, 3.2 mm cod end,
midwater trawl is begun 2 to 3 days after release. When the first fish
is caught, full-time trawling 7 days a week should begin. Each day's
trawling consists of ten 20 minute tows generally made against the
current, and distributed equally across the channel.
(A) The Chipps Island smolt survival index is calculated as:
SSI=RMT(0.007692)
where R=number of recaptures of tagged fish
M=number of marked (tagged) fish released
T=proportion of time sampled vs total time tagged fish were passing the
site (i.e. time between first and last tagged fish recovery)
Where the value 0.007692 is the proportion of the channel width fished
by the trawl, and is calculated as trawl width/channel width.
(B) Recoveries of tagged fish from the ocean salmon fishery two to
four years after release are also used to calculate a survival index
for each release. Smolt survival indices from ocean recoveries are
calculated as:
OSI=R1/M1R2/M2
where R1=number of tagged adults recovered from the upstream
release
M1=number released upstream
R2=number of tagged adults recovered from the Port Chicago release
M2=number released at Port Chicago
(1) The number of tagged adults recovered from the ocean fishery is
provided by the Pacific States Marine Fisheries Commission, which
maintains a port sampling program.
(2) [Reserved]
(iii) Computing fish migration criteria values for San Joaquin
River. In order to assess annual fish migration criteria values for the
San Joaquin River, tagged salmon smolts will be released into the San
Joaquin River at Mossdale and captured at Chipps Island, or
alternatively released at Mossdale and Port Chicago and recovered from
the ocean fishery, using the methodology described in paragraph
(a)(2)(iii). An alternative methodology for computing fish migration
criteria values can be used so long as the revised methodology is
calibrated with the methodology described below so as to maintain the
validity of the relative index values. Sufficient releases shall be
made each year to provide a statistically reliable estimate of the
SJFMC for the year. These criteria will be considered attained when the
sum of the differences between the measured experimental value and the
stated criteria value (i.e., measured value minus stated value) for
each experimental release conducted over a three year period (the
current year and the previous two years) shall be greater than or equal
to zero.
(A) Fish for release are to be tagged at the hatchery with coded-
wire tags, and fin clipped. Approximately 50,000 to 100,000 fish of
smolt size (size greater than 75 mm) are released for each survival
index estimate, depending on expected mortality. As a control for the
ocean recovery survival index, one or two groups per season are
released at Benicia or Pt. Chicago. From each upstream release of
tagged fish, fish are to be caught over a period of one to two weeks at
Chipps Island. Daylight sampling at Chipps Island with a 9.1 by 7.9 m,
3.2 mm cod end, midwater trawl is begun 2 to 3 days after release. When
the first fish is caught, full-time trawling 7 days a week should
begin. Each day's trawling consists of ten 20 minute tows generally
made against the current, and distributed equally across the channel.
(B) The Chipps Island smolt survival index is calculated as:
SSI=RMT(0.007692)
where R=number of recaptures of tagged fish
M=number of marked (tagged) fish released
T=proportion of time sampled vs total time tagged fish were passing the
site (i.e. time between first and last tagged fish recovery)
Where the value 0.007692 is the proportion of the channel width fished
by the trawl, and is calculated as trawl width/channel width.
(C) Recoveries of tagged fish from the ocean salmon fishery two to
four years after release are also used to calculate a survival index
for each release. Smolt survival indices from ocean recoveries are
calculated as:
[[Page 4709]] OSI=R1/M1 R2/M2
where R1=number of tagged adults recovered from the upstream
release
M1=number released upstream
R2=number of tagged adults recovered from the Port Chicago release
M2=number released at Port Chicago
(1) The number of tagged adults recovered from the ocean fishery is
provided by the Pacific States Marine Fisheries Commission, which
maintains a port sampling program.
(2) [Reserved]
(3) Suisun marsh criteria. (i) Water quality conditions sufficient
to support a natural gradient in species composition and wildlife
habitat characteristic of a brackish marsh throughout all elevations of
the tidal marshes bordering Suisun Bay shall be maintained. Water
quality conditions shall be maintained so that none of the following
occurs: Loss of diversity; conversion of brackish marsh to salt marsh;
for animals, decreased population abundance of those species vulnerable
to increased mortality and loss of habitat from increased water
salinity; or for plants, significant reduction in stature or percent
cover from increased water or soil salinity or other water quality
parameters.
(ii) [Reserved]
(b) Revised criteria. The following criteria are applicable to
state waters specified in Table 1-1, at Section (C)(3) (``Striped
Bass--Salinity : 3. Prisoners Point--Spawning) of the Water Quality
Control Plan for Salinity for the San Francisco Bay--Sacramento/San
Joaquin Delta Estuary, adopted by the California State Water Resources
Control Board in State Board Resolution No. 91-34 on May 1, 1991:
--------------------------------------------------------------------------------------------------------------------------------------------------------
Sampling site Nos (I-- San Joaquin
Location A/RKI) Parameter Description Index type Valley Index Dates Values
--------------------------------------------------------------------------------------------------------------------------------------------------------
San Joaquin River D15/RSAN018, Specific......... 14-day running Not Applicable... >2.5 MAF April 1 to May 31 0.44 micro-mhos.
at Jersey Point, C4/RSAN032, Conductance...... average of mean
San Andreas D29/RSAN038, @ 25 deg.C...... daily for the
Landing, P8/RSAN056, period not more
Prisoners Point, -/RSAN062, than value
Buckley Cove, C6/RSAN073, shown, in mmhos.
Rough and Ready C7/RSAN087,
Island, Brandt C10/RSAN112
Bridge, Mossdale,
and Vernalis.
San Joaquin River D15/RSAN018, Specific 14-day running Not Applicable... 2.5 April 1 to May 31 0.44 micro-mhos.
at Jersey Point, C4/RSAN032, Conductance. average of mean MAF
San Andreas D29/RSAN038 daily for the
Landing and period not more
Prisoners Point. than value
shown, in mmhos.
--------------------------------------------------------------------------------------------------------------------------------------------------------
(c) Definitions. Terms used in paragraphs (a) and (b) of this
section, shall be defined as follows:
(1) Water year. A water year is the twelve calendar months
beginning October 1.
(2) 8-River Index. The flow determinations are made and are
published by the California Department of Water Resources in Bulletin
120. The 8-River Index shall be computed as the sum of flows at the
following stations:
(i) Sacramento River at Band Bridge, near Red Bluff;
(ii) Feather River, total inflow to Oroville Reservoir;
(iii) Yuba River at Smartville;
(iv) American River, total inflow to Folsom Reservoir;
(v) Stanislaus River, total inflow to New Melones Reservoir;
(vi) Tuolumne River, total inflow to Don Pedro Reservoir;
(vii) Merced River, total inflow to Exchequer Reservoir; and
(viii) San Joaquin River, total inflow to Millerton Lake.
(3) San Joaquin Valley Index. (i) The San Joaquin Valley Index is
computed according to the following formula:
ISJ=0.6X+0.2Y and 0.2Z
where ISJ=San Joaquin Valley Index
X=Current year's April-July San Joaquin Valley unimpaired runoff
Y=Current year's October-March San Joaquin Valley unimpaired runoff
Z=Previous year's index in MAF, not to exceed 0.9 MAF
(ii) Measuring San Joaquin Valley unimpaired runoff. San Joaquin
Valley unimpaired runoff for the current water year is a forecast of
the sum of the following locations: Stanislaus River, total flow to New
Melones Reservoir; Tuolumne River, total inflow to Don Pedro Reservoir;
Merced River, total flow to Exchequer Reservoir; San Joaquin River,
total inflow to Millerton Lake.
(4) Salinity. Salinity is the total concentration of dissolved ions
in water. It shall be measured by specific conductance in accordance
with the procedures set forth in 40 CFR 136.3, Table 1B, Parameter 64.
[FR Doc. 95-817 Filed 1-23-95; 8:45 am]
BILLING CODE 6560-50-P