4664 Federal Register / Vol. 60, No. 15 / Tuesday, January 24, 1995 / Rules and Regulations

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.

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
Federal Register / Vol. 60, No. 15 / Tuesday, January 24, 1995 / Rules and Regulations 4665

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.

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.

3The 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.’’

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).

5As 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.

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

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).

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.

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

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
4666 Federal Register / Vol. 60, No. 15 / Tuesday, January 24, 1995 / Rules and Regulations

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/SacramentoSan 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 winterrun 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
Federal Register / Vol. 60, No. 15 / Tuesday, January 24, 1995 / Rules and Regulations 4667

6As 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.

7As discussed below, a state’s water quality

standards must also contain an antidegradation

policy.

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.

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

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.
4668 Federal Register / Vol. 60, No. 15 / Tuesday, January 24, 1995 / Rules and Regulations

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
Federal Register / Vol. 60, No. 15 / Tuesday, January 24, 1995 / Rules and Regulations 4669

8As 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.’’

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.

BILLING CODE 6560–50–P
4670 Federal Register / Vol. 60, No. 15 / Tuesday, January 24, 1995 / Rules and Regulations

BILLING CODE 6560–50–C
Federal Register / Vol. 60, No. 15 / Tuesday, January 24, 1995 / Rules and Regulations 4671

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.

10Low 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).

11The 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 °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.

(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.

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).

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.

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:
4672 Federal Register / Vol. 60, No. 15 / Tuesday, January 24, 1995 / Rules and Regulations

12EPA’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°C.

13A 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.

14Spring and neap tides refer to the times during

the 28 day lunar cycle when tides are strongest and

weakest, respectively.

(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

criteria 12 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 KimmererMonismith model (SFEP 1993) was used

to estimate the salinity regime based on

the existing flow data.

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
Federal Register / Vol. 60, No. 15 / Tuesday, January 24, 1995 / Rules and Regulations 4673

15The 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.

16The Sacramento River basin usually accounts

for about 80% of net Delta outflow, with the

remainder coming primarily from the San Joaquin

River basin.

TABLE 1.—PROPOSED 2 PPT ESTUARINE HABITAT CRITERIA 1

Year type Roe Island [km 64] Chipps Island [km 74] Confluence

[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.

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
4674 Federal Register / Vol. 60, No. 15 / Tuesday, January 24, 1995 / Rules and Regulations

17As 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 BaySacramento 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.’’

18The 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)

).

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

(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

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
Federal Register / Vol. 60, No. 15 / Tuesday, January 24, 1995 / Rules and Regulations 4675

19While 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.

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

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.

Billing Code 6560–50–P
4676 Federal Register / Vol. 60, No. 15 / Tuesday, January 24, 1995 / Rules and Regulations

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.

21The 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.

BILLING CODE 6560–50–C

(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.

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
Federal Register / Vol. 60, No. 15 / Tuesday, January 24, 1995 / Rules and Regulations 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).

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

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.

BILLING CODE 6560–50–P

BILLING CODE 6560–50–C

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
4678 Federal Register / Vol. 60, No. 15 / Tuesday, January 24, 1995 / Rules and Regulations

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.

BILLING CODE 6560–50–P
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4680 Federal Register / Vol. 60, No. 15 / Tuesday, January 24, 1995 / Rules and Regulations

23That 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.

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 acrefeet, 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-tomonth 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

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-bymonth 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.

PMI

Chipps Island Roe Island (if triggered)

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
Federal Register / Vol. 60, No. 15 / Tuesday, January 24, 1995 / Rules and Regulations 4681

24The 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.

PMI

Chipps Island Roe Island (if triggered)

Feb Mar Apr May Jun Feb Mar Apr May

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

BILLING CODE 6560–50–P
4682 Federal Register / Vol. 60, No. 15 / Tuesday, January 24, 1995 / Rules and Regulations

BILLING CODE 6560–50–C
Federal Register / Vol. 60, No. 15 / Tuesday, January 24, 1995 / Rules and Regulations 4683

25A ‘‘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.

26These salmon smolt survival index equations

were based in large part on the results of taggedfish 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.

27There 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.

28For 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.

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 fallrun 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, springrun 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 springrun 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 freshwater 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

§ 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

§ 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

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

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
4684 Federal Register / Vol. 60, No. 15 / Tuesday, January 24, 1995 / Rules and Regulations

29As stated above, the standard water year

categories are wet, above normal, below normal,

dry, and critically dry years.

30This 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.

31That 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.

32The 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.

33For 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 newlyspawned eggs.

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.

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.

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.

(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.

(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
Federal Register / Vol. 60, No. 15 / Tuesday, January 24, 1995 / Rules and Regulations 4685

34Since 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.

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.

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

Water year

type

Criteria

value

Water year

type

Criteria

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,
4686 Federal Register / Vol. 60, No. 15 / Tuesday, January 24, 1995 / Rules and Regulations

35This 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.

36Approximating this line was done through a

standard least squares ‘‘best fit’’ computation.

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 taggedfish release results indicate that, except

in very high temperature periods, those

periods in which the Delta CrossChannel 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° 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° 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°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°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

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 approximate 36 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).

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
Federal Register / Vol. 60, No. 15 / Tuesday, January 24, 1995 / Rules and Regulations 4687

Improvement Act mandates a

‘‘doubling’’ goal for anadromous fish.

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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°F:

SRFMC=1.35

At temperatures between 61°F and 72°F:

SRFMC=6.96 ¥ .092 * Fahrenheit

temperature

At temperatures above 72°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°F and 72°F ceiling and

floor levels.

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(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 withinyear 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
4690 Federal Register / Vol. 60, No. 15 / Tuesday, January 24, 1995 / Rules and Regulations

37EPA 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.

38The 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.

39As 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.

40As 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.

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 taggedfish 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.

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

index 38 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.

(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.

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
Federal Register / Vol. 60, No. 15 / Tuesday, January 24, 1995 / Rules and Regulations 4691

41The 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 °F in April and 65 °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.

TABLE 4.—SAN JOAQUIN MANAGEMENT MEASURES COMPARED

Alternative Max Total CVP/SWP Exports in cfs Barrier Upper Old River Vernalis Flow

Index Values

on San Joaquin

EPA ............................... 4/15 to 5/15 1500

4/1 to 4/15 & 5/16 to 5/31

W 1 6000

AN 5000

BN 4000

D 3000

C 2000

4/15 to 5/15 All Year Types 4/15 to 5/5 Minimum CFS

W 10000

AN 8000

BN 6000

D 4000

C 4000

Other flows from 4/1 to 5/31 same as

DWRSIM run used by USFWS for

D–1630

W .49 2

AN .35

BN .28

D .22

C .22

Avg = .33

USFWS .......................... 4/15 to 5/15

W 6000

AN 5000

BN 4000

D 3000

C 2000

4/1 to 5/31 All Year Types 4/15 to 5/15 Minimum CFS

W 10000

AN 8000

BN 6000

D 4000

C 2000

Other flows from 4/1 to 5/31 same as

DWRSIM run used by USFWS for

D–1630

W .49

AN .41

BN .40

D .35

C .32

Avg = .41

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). 2For 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.

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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42These 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.

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 taggedfish 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.

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
4696 Federal Register / Vol. 60, No. 15 / Tuesday, January 24, 1995 / Rules and Regulations

43Salinity 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°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.

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).

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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 crosspurposes 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 § 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 softhaired 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
Federal Register / Vol. 60, No. 15 / Tuesday, January 24, 1995 / Rules and Regulations 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
4700 Federal Register / Vol. 60, No. 15 / Tuesday, January 24, 1995 / Rules and Regulations

44The 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.

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

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
Federal Register / Vol. 60, No. 15 / Tuesday, January 24, 1995 / Rules and Regulations 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 ExportersOnly 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
4702 Federal Register / Vol. 60, No. 15 / Tuesday, January 24, 1995 / Rules and Regulations

BILLING CODE 6560–50–C
Federal Register / Vol. 60, No. 15 / Tuesday, January 24, 1995 / Rules and Regulations 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 ProjectExporters 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

value

Dry

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. 1Transfers are from agriculture to agriculture. 2Transfers 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., statusquo), 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
4704 Federal Register / Vol. 60, No. 15 / Tuesday, January 24, 1995 / Rules and Regulations

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
Federal Register / Vol. 60, No. 15 / Tuesday, January 24, 1995 / Rules and Regulations 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
4706 Federal Register / Vol. 60, No. 15 / Tuesday, January 24, 1995 / Rules and Regulations

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

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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.

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1990a. Central Valley Salmon and Steelhead

Restoration and Enhancement Plan. 115 pp.

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1990b. Testimony of Department for Fish and

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1992a. Water quality and water quantity

needs for chinook salmon production in the

Upper Sacramento River. Prepared for the

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WRINT–DFG–14.

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1992b. Summary and Recommendations for

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1993. Biological Assessment for South Delta

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Section 7 Endangered Species Permit.

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1994. Comments on the Water Quality

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88+ pp. comment booklet and 7 appendices.

California Farm Bureau Federation, 1994.

Letter from B. Vice to C. Browner dated April

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California State Lands Commission, 1991.

Delta-Estuary: California’s Inland Coast, A

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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

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California Urban Water Agencies, 1994b.

Recommendations to the State Water

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Francisco Bay-Sacramento and San Joaquin

River Delta Estuary, August 25, 1994. 46 pp.

plus 2 appendices.

Carter, H., and G. Goldman, 1992. The

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Center for Economic Policy Research, 1992.

An Economic Analysis of Water Availability

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Phase III Draft Report. Stanford, California.

City & County of San Francisco Public

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Moran to P. Wright dated March 11, 1994. 2

pp., plus attachments.

Collins, J.N. and T.C. Foin, 1993.

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Denton, R.A., 1993. Accounting for

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93, vol. 1, pp. 448–453.

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the G-Model Fit of Electrical Conductivity

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Five Agency Delta Salmon Team, 1991a.

Evaluation of the Feasibility of Protecting

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Five Agency Delta Salmon Team, 1991b.

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and Trends Report on Wildlife of the San

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San Francisco Estuary Project Status and

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San Francisco Estuary. March 1992. 257 pp.

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increased salinity in the Suisun Marsh

Brackish wetlands. WRINT–NHI–12. 6 pp.

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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

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Meng, L., 1994. Status Report on

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Fishes, Aquatic Diversity Management Areas,

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for Salinity, San Francisco Bay/SacramentoSan Joaquin Delta Estuary. 91–15WR, May

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in the Sacramento and San Joaquin Rivers in

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Turner, J.L., 1972b. Striped Bass in

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Turner, J.L. and H.K. Chadwick, 1972.

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striped bass (Morone saxatilis) in relation to

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Turner, J.L. and T.C. Farley, 1971. Effects

of temperature, salinity, and dissolved

oxygen on the survival of striped bass eggs

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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 SacramentoSan Joaquin Estuary. WRINT–USFWS–9.

1991 Annual Progress Report. SacramentoSan 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:

§ 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 °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 °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.

Month X

Chipps Island Roe Island (if triggered)

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
4708 Federal Register / Vol. 60, No. 15 / Tuesday, January 24, 1995 / Rules and Regulations

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°F:

SRFMC = 1.35

At temperatures between 61°F and 72

°F: SRFMC = 6.96–.092 *

Fahrenheit temperature

At temperatures greater than 72 °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 codedwire 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=R÷MT(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/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]

(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=R÷MT(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:
Federal Register / Vol. 60, No. 15 / Tuesday, January 24, 1995 / Rules and Regulations 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:

Location Sampling site

Nos (I–-A/RKI) Parameter Description Index type San JoaquinValley Index Dates Values

San Joaquin

River at Jersey Point,

San Andreas

Landing, Prisoners Point,

Buckley

Cove, Rough

and Ready Island, Brandt

Bridge,

Mossdale,

and Vernalis.

D15/RSAN018,

C4/RSAN032,

D29/RSAN038,

P8/RSAN056,

-/RSAN062,

C6/RSAN073,

C7/RSAN087,

C10/RSAN112

Specific ............

Conductance ...

@ 25 °C ...........

14-day running

average of

mean daily

for the period

not more than

value shown,

in mmhos.

Not Applicable . >2.5 MAF April 1 to May

31.

0.44 micromhos.

San Joaquin

River at Jersey Point,

San Andreas

Landing and

Prisoners

Point.

D15/RSAN018,

C4/RSAN032,

D29/RSAN038

Specific Conductance.14-day running

average of

mean daily

for the period

not more than

value shown,

in mmhos.

Not Applicable . ≤2.5 MAF April 1 to May

31.

0.44 micromhos.

(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]

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