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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81JMMARY AND PRINCIPAL CONCLUSIONS

Inter-Agency Study Assessed Impacts Of Glen Canyon
Daa Operations

This report presents the findings of the Glen Canyon
Environmental Studies (GCES). In December of 1982, the
Secretary of the Interior directed the Bureau of
Reclamation (BOR) to in.itiate a mUlti-agency study to
address the concerns of the pUblic and other federal
and state agencies abou.t possible negative effects of
the operations of Gle:n Canyon Dam on downstream
environmental and recre:ational resources. This studY
was not intended nor desianed to lead directlY to
chanaes in dam operat.ions. Any decision to make
operational changes would require feasibility studies
and National Environment~al Policy Act (NEPA) compliance
activities to assess thet impact of those changes on the
primary mandate of the'Colorado River Storage Project
(water storage and deli.very and power generation), as
well as on the environmemt and recreation.

The GCES study goals were, f.i.rst, to investigate the
w'S4,{",~J;~'t',o"simpact of several aspect:s of current dam operations on
the existing environmental and recreational resources
in the Glen Canyon Nati.onal Recreation Area and Grand
Canyon National Park--specifically the effect of very
high, very low, and strongly fluctuating releases from
the dam. Second, if cldverse impacts to downstream
resources were found, the study was to determine
whether modifications 11lade to dam operations, within
the constraints of Colorado River storage Project water
delivery requirements, could reduce those impacts. To
accomplish the study g()als, over 30 technical studies
in the fields of biology, recreation, and sediment and
hydrology were conducted by over 100 researchers.

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