FEB 23 2004

IN REPLY REFER TO: UC-720 ENV-6.00

Interested Parties

Subject: Glen Canyon Dam Temperature Control Device Environmental Assessment

Dear Interested Parties:

I am personally inviting you to assist the Bureau of Reclamation and its partners in scoping the issues to be considered in the development of an Environmental Assessment (EA) under terms of the National Environmental Policy Act. As you will see, we are again considering the feasibility of installing temperature control devices (TCD) on the penstocks at Glen Canyon Dam, Arizona to study the potential benefits of warming the temperature of water released from the dam to the downstream Colorado River through Glen and Grand Canyons.

Prior to construction of Glen Canyon Dam, Colorado River temperatures ranged from freezing to about 85 OF. Since construction of the dam, releases from the dam have been consistently cold (about 45-50 OF), adversely impacting native fish. Reviewing the condition of the native fish in 1994, the U.S. Fish and Wildlife Service's biological opinion on the operation of Glen Canyon Dam Environmental Impact Statement required Reclamation to evaluate the feasibility of using a TCD to warm the temperature of the Colorado River below Glen Canyon Dam.

In January 1999, Reclamation released a draft EA on an eight-unit TCD for Glen Canyon Dam. Reclamation did not finalize this assessment and National Environmental Policy Act process due to questions about potential adverse impacts of the eight-unit device on downstream aquatic resources, particularly endangered fish, the need for an accompanying science plan, and concerns about the frequency of use of the TCD. Reclamation has continued studying the potential for a TCD that could warm the Colorado River below the dam and assist in the removal of jeopardy from endangered fish. Based on these additional studies, Reclamation has decided to begin preparation of a new programmatic EA analyzing the environmental effects of construction and experimental operation of a two-unit pilot project TCD. A monitoring plan and experimental program for testing the TCD using adaptive management will be designed by the U.S. Geological Survey, Grand Canyon Monitoring and Research Center.

This notice announces the opening of a 30 day scoping period. During this time, Reclamation encourages you to raise issues and concerns that should be addressed in the EA. You should focus your comments on the potential environmental effects of construction and operation of a two-unit pilot project TCD, as well as reasonable alternatives to the proposal and measures to avoid or lessen environmental impact. Comments received before April 2, 2004, will be considered during the preparation of the EA. Reclamation will use the EA in its decision-making process to determine whether to construct and test a pilot two-unit TCD or if a more detailed environmental impact statement should be prepared.

Comments should be sent to the U.S. Bureau of Reclamation, attention Nancy Coulam, UC-720, 125 South State Street, Room 6103, Salt Lake City, UT 84138-1102 or by email to ea_comments@uc.usbr.gov. If you do not want to submit comments at this time, but would like to receive a copy of the draft EA and other mailings, please contact Reclamation at the same address or email. If you need further information, please contact Nancy Coulam at 801-524-3684.

Sincerely,

Rick L. Gold Regional Director

Back | Top
Last Update: October 30, 2007