WSP03403

• File Number: 8220.101.09
• Description: Glen Canyon Dam/Lake Powell
• State: AZ
• Basin: Colorado Mainstem
• Date: 1/1/1989
• Author: USDOI-BOR
• Title: Glen Canyon Environmental Studies Update - January 1989
• Water Supply Pro - Doc Type: Publication

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'J

1982 To The
Present

In December 1982, the
Department of the Interior
(Department) di rected that
the GCES Program be initiated
as part of the Environmental
Assessment of the uprating
and rewinding of the
generators at Glen Canyon
Dam. The primary objective
was to see how the present
flow patterns impact upon the
total riverine environment in
the Grand Canyon and how
various low-flow p!lriods
at feet rafting and the
fisheries resources in the
river.
Phase I of the GCES Program
focused on the collection of
the technical information
necessary to quantity the
impact that the present
operation of Glen Canyon Dam
is having on the downstream
resources of the Grand Canyon.
The GCES Technical Report,
issued in January 1988,
reflects the GCES Phase I
lindings. The National Academy
of Sciences completed their
involvement in Phase I
activities with the publishing
of their review report in
December 1987.
The GCES Executive Review
Committee (ERC) took the GCES
phase I information and
through oS review of potential
management impacts, determined
that several critical segments
of information were still
required and therefore a
decision on the impact of
'operations of Glen canyon dam
could not be made. Its
recommendations for further
studies were articulated in
the May 1988 ERC Report which
was forwarded to the
Department for review and

decision.
Upon review of these
documents, the Department
concurred with the Executive
Review Committee that
addi tional studies needed to
be completed prior to the
Department making a decision
on any additional operational
studies at Glen Canyon Dam.
On June 16, 1988, the
Assistant Secretary for water
and Science and the Assistant
Secretary for Fish, Wildlife
and Parks issued a directive
to the cooperative bureaus of
the GCES Program to initiate
the additional studies (Glen
canyon phase III.
The GCES Phase II efforts
are a much reduced technical
version of the initial
program and are focused on
completion of low and
fluctuating flow studies on
the endangered fish, the
trout, and the beaches of the
Grand canyon. Additionally,
the Phase II etrort will
address the economic
relationship between the
operation of Glen Canyon Dam
and the power users. The
National Academy of sciences
(NAB) is being retained to
review the overall scientific

process.
GCES phase II Program is a
cooperative effort among
Reclamation, the National
Pa rk Service, Fish and
wildlife service, U.s.
Geologiea1 survey, ArlEona
Game , Fish Department,
private consultants and
academic institutions.
Addi tiona! input is provided
from Western Area Power

Administration

(Western),
the Lower
Reg ion
the Colorado

power users,
Colorado
(Reclamation) ,

River

Basin

states,
groups,

environmental

recreation groups, and
additional private
consultants.
The additional GCES etforts
have been separated into two
segments. Phase II will
focus on the technical
studies and Phase III will
focus on the deci.ion proce..
within the Department of the
Interior. A draft GCES Phase
II Implementation Plan has
been presented to the
constituent groups and
discussion meetings are being
scheduled for January 1989.

Study Teams

Two primary study teams
have been organiEed: the
Envi ronmenta1 study Team and
the Economic study Team. The
Environmental study Team will
be responsible for the
development of the technical
study plans associated with
trout, endangered species,
and beach aggradation and
degradation. They will
follow a four st.p process:
1. Develop and agre. on
the technical needs of the
studies. This will include
determination of the study
timing, study flow needs,
technical data requirements
and review requirements.
2. An outline of the study
flow requirements will be
provided to Western which
will determine the impact of
the technical studies on the
power users. Western will be
responsible for coordination
with the power users.
3. The decision to proceed
will be made by the ERC after
the power impact assessment
is complete. If the impacts
are determined to be too
great, contingency plans will