7423

• UCREFRP Catalog Number: 7423
• Author: U.S. Bureau of Reclamation.
• Title: Glen Canyon Environmental Studies Draft Report, September 1987.
• USFW Year: 1987.
• USFW - Doc Type: Washington, D.C.
• Copyright Material: NO

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SECTION I: INTRODUCTION

The Glen Canyon Environmental Studies Assessed The
Impact of Dam operations

The Glen Canyon Environmental Studies (GCES) are a
mUlti-agency effort to study the impacts of Glen Canyon
Dam operations on the environmental and recreational
resources of the ColoradO River downstream of the dam.
This reach of river flows first through 15 miles of
Glen Canyon, then through 277 miles of the Grand Canyon
before entering Lake Mead (see location maps in Figures
I-1 and I-2).

In recognition of the concerns of the public and other
governmental agencies, the Bureau of Reclamation (BaR)
was directed by the Department of the Interior to
conduct a general study of the short- and long-term
effects of current Glen Canyon Dam operations on
vegetation, wildlife, fisheries, recreation, beaches,
and other environmental resources. These studies were
to evaluate fluctuating flows, low flows, and high
flows to determine their effect on resources. The
GCES were a cooperative effort between the BaR, the Na-
tional Park Service (NPS) , and the u.s. Fish and
Wildlife Service (FWS). Cooperation and contributions
to the study came from the Arizona Department of Game
and Fish (AGF) , the u.s. Geological Survey (USGS),
private consultants, universities, and private and com-
mercial river runners and guides.

The studies were formulated to answer two questions:

(1) Are current operations of the dam, through control
of the flows in the Colorado River, adversely affectinq
the existina river-related environmental and recreat-
ional resources of Glen Canyon and Grand Canyon?

(2) Are there ways to operate the dam, consistent with
Colorado River storage Project (CRSP) water delivery
requirements, that would improve or better protect the
environmental and recreational resources?

The modified dam operations developed and evaluated in
answer to the second question were designed onlY with
the goal of protecting or enhancing downstream
environmental and recreational resources, constrained