WSP07578

• File Number: 8220.101.17
• Description: Glen Canyon Dam/Lake Powell
• State: AZ
• Basin: Colorado Mainstem
• Date: 7/1/1998
• Title: Comments re: GCD Modifications to Control Downstream Temperatures: Preliminary Draft Plan and Environmental Assessment
• Water Supply Pro - Doc Type: EIS

Colorado Water Conservation Board
Department of Natural Resources
721 Centennial Building
, 31 3 Sherman Street
Denver, Colorado 80203
Phone, [phone]
FAX, 13031 866.4474

STATE OF COLORADO

8

August 18. 1998

Roy Romer
Governor
Itunes 5. Lochheild
Executive Director, DNR
Darie~C. llle, PE.
Director, CWCB
Pl"ter H. ~"'~l'\'j,
Acting Director, CWCB

Mr. Dave Truman
Bureau of Reclamation
Upper Colorado Region
125 South State Street. Room 6107
Salt Lake City. UT 84138-1102

Dear Mr. Truman:

Thank you for the opportunity to review and comment on the Bureau's Preliminary Draft Plan
anl1 Environmental Assessment (EA) on the Glen Canyon Dam Temperature Control Structure
(TCS). The following are our comments on the Draft Plan and EA:

We are concerned that the operation of the TCS may benefit non-native fish more than the
federally endangered humpback chub and other native species. While the Plan and EA recognize
non-native fishes will benefit from warm water releases, and potentially increase competition
between natives and non-natives. it assumes with little or no evidence that the benefit to native
fishes outweighs the risk, and that any adverse impacts to the native fishes can be reversed
through operational changes of the TCS and adaptive management. While temperature changes
are reversible, there is no scientific evidence presented in the documents that addresses reversal
of impacts to native and non-natives. We are concerned that if adaptive management and
operational changes cannot reverse adverse impacts, extraordinary measures may be necessary to
the operation of Glen Canyon Dam that would adversely affect Upper Basin water supplies. The
Bureau and the Fish and Wildlife Service (FWS) need to provide greater assurance that adverse
impacts can be avoided or if they occur can be reversed through the adaptive management
program. We therefore recommend that Reclamation and the FWS develop a plan to address this
issue, conduct additional research, and do whatever is necessary to provide a greater level of
assurance.

The installation and operation of the TCS will require a significant new monitoring and research
program both above and below Glen Canyon Dam by the GCMRC and significant funding that is
presently not included in the 5-year adaptive management program budget. We recommend that
the GCMRC develop a preliminary monitoring and research program and a long-term budget,
and that this program and budget be included in the Bureau's Plan and EA.

In Chapter II, several alternatives are described and eliminated based purely on economic and
technical limitations, implying that otherwise they would be viable alternatives. We believe that
holding the reservoir at minimum pool, removing Glen Canyon Dam and using the existing
spillway structures to bypass the power plant, are not options under the Law of the River, and in