Surges of Colorado River water may be released soon from Glen Canyon Dam in an experiment to find ways to repair the natural setting of the Grand Canyon.

If approved, the tests would be carried out this month. They are intended to see if high river flows can restore sandbar deposits in the canyon's upper reaches. They also may re-create backwater channels, which are thought to be good spawning areas and habitat for the endangered humpback chub and other native fish.

In addition, the U.S. Bureau of Reclamation would like to remove non-native trout that feed on young humpback chubs near the confluence with the Little Colorado River, according to a recent environmental study. The Little Colorado is the only stream in the Grand Canyon where the chub reproduces and survives to adulthood.

Reclamation, part of the Interior Department, has been seeking comments on a draft environmental assessment concerning the high-flow test experiment.

Interior Secretary Gale Norton said in a prepared statement, "Interior continues to support the application of science and adaptive management to the operation of Glen Canyon Dam and the management of natural resources in Glen and Grand Canyon.

"Experiments such as this high-flow test continue to advance our understanding of the ecosystem while providing tangible benefits to the fishery, river environment and recreational users in Grand Canyon National Park."

This past August, a group studying sediment problems recommended that high-flow tests be considered if enough sediment had built up in the Colorado River near its confluence with the Paria River.

The experiment would cost electrical power customers $1.7 million, apparently in reduced generating capacity at the dam, according to the assessment. By comparison, 2003 power revenues were estimated at about $130 million.

---

E-mail: bau@desnews.com