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Commentaries and editorials

Water Quality Team Adopts
Temperature Model for Dams

by Mike O'Bryant
Columbia Basin Bulletin - September 5, 2003

A technical work group of the Water Quality Team this summer adopted a water temperature model that will help the Technical Management Team make more informed in-season decisions about the immediate effects of operations at the dams on the Snake River. The model will be ready for TMT use by summer 2004.

The development of the model, long asked for by TMT, is a requirement of NOAA Fisheries 2000 biological opinion of the Columbia River power system. The Reasonable and Prudent Alternative action 143 requires water temperature modeling and a data collection plan for lower Snake River dams, said Mark Schneider of NOAA Fisheries during a report to the Implementation Team this week. The RPA states:

"The Action Agencies shall develop and coordinate with NOAA Fisheries and EPA on a plan to model the water temperature effects of alternative Snake River Operations. The modeling plan shall include a temperature data collection strategy developed in consultation with EPA, NOAA Fisheries and state and tribal water quality agencies. The data collection strategy shall be sufficient to develop and operate the model and to document the effects of project operations."

One way the model and data collection strategy would help is to directly monitor the effects of cool water releases from Dworshak Dam at Lower Granite Dam during the summer. For the past few years, that operation has given TMT a tool to keep tailwater and forebay temperatures lower than would normally occur at the dam during the late summer months when Snake River water warms up. This new model will enable river managers to track in real time the impacts on water temperature as the water is released.

The effort began in March 2002, Schneider said, when the Water Quality Team pulled together a work group from the Bonneville Power Administration, the Columbia River Inter-Tribal Fish Commission, the Environmental Protection Agency, Idaho Power, Idaho Department of Environmental Quality, Idaho Water Resources Department, the Nez Perce Nation, NOAA Fisheries, the Fish Passage Center, USACE and the Washington Department of Fish and Wildlife.

He said the team also made some recommendations for follow up work beyond the lower Snake River.

After reviewing several models, the team chose the Corps' CE-QUAL-W2, 2-dimensional model that has been in development since the 1970s, said Joe Carroll of the Corps. With the installation of data collection monitors in the Clearwater and Snake rivers and in reservoir locations (various locations, various depths), the model is able to predict in real time the results of a change in operations.

"With this tool in place, we think in a couple of years down the line, we will be able to determine what temperature we want and what date we want it and set the operations to meet that," said team member Ben Cope of the EPA. "With the debate about the early or later use of water, this tool could save water. Hopefully, it will be a useful model for management.

Schneider said the team will enlist the help of TMT to fine tune the model and will have it available for real time use when summer fish operations begin.

Related Sites:
Technical Management Team:

Mike O'Bryant
Water Quality Team Adopts Temperature Model for Dams
Columbia Basin Bulletin, September 5, 2003

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