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River Operators Assess 2003 Dam/Reservoir Operations for Fish

by CBB Staff
Columbia Basin Bulletin - November 7, 2003

The Technical Management Team reviewed 2003 operations at Columbia and Snake River dams and declared the year largely to be a success.

Each year in November, TMT reviews in season operating decisions it made during the previous fiscal year, Oct. 1 through Sept. 30. This year it found significant successes in using water from Dworshak Dam to cool Snake River water into mid-September, two weeks beyond operations called for by the NOAA Fisheries 2000 biological opinion.

In addition, it was noted at the meeting that changes in the U.S. Army Corps of Engineers' flood control operations this spring resulted in additional water available from Dworshak reservoir that could be used when it was needed the most.

On the other side of the ledger, while survival of spring migrants exceeded BiOp targets, survival of summer migrating fall chinook and steelhead that were left in the river through lower Snake River dams did not, nor did upper and mid-Columbia River steelhead.

However, system survival did meet BiOp targets. System survival includes juveniles barged through the Snake and Columbia River systems and adjusts barged fish survival by an assumed delayed mortality value.

"We used the tools available to us and used good judgment this year," said Donna Silverberg, facilitator throughout the year for TMT. "We're getting better and smarter in making decisions."

In April, TMT asked for a change in flood control operations at Dworshak Dam in order to save more water in the reservoir so it could be used later to gain higher flows in the lower Snake River. That left the reservoir's elevation higher than normal on the critical end of March flood control date. The operation called for a shift that resulted in more stored water in the Dworshak reservoir while releasing more water from Grand Coulee Dam. An initial low water supply forecast of 67 to 69 percent of normal facilitated the change, although, with unexpected late rain and snow, the basin ended the year with an 87 percent of normal water supply.

The change in flood control allowed the Corps to hold 15 feet of storage to be used for lower Snake River flow augmentation, and it allowed TMT to extend high summer flows from Dworshak beyond the Aug. 31 planning date of the BiOp to Sept. 15 in order to aid with Dworshak's cool water late migrating juveniles and returning adult fall chinook.

"The April operation was great," said Chris Ross of NOAA Fisheries. "It put a lot of water on the fish."

However, shifting flood control operations isn't always something the Corps can do, said the Corps' Cindy Henriksen. "We're always willing to look at it, but the concern is that we'd then see a big rain event during the April period," she said. "If so, we probably would have had to release more water earlier. We have to watch closely when doing this."

"This was a hot year with low water," said Dave Statler of the Nez Perce Tribes. "Under these conditions it was a challenge to keep the lower river cool with the only tool available to us

  • Dworshak. We did as well as we could and used the water to the best advantage."

    Other issues, conditions and statistics discussed by TMT include (not all are related to operations under the control of TMT):

    Martin predicts near normal precipitation and colder winter temperatures for 2004. The water supply, he predicted, would be near normal at 104 maf, or 97 percent of normal. Another forecast put the water supply at 110 maf, or 102 percent of normal. John Wellschlager of the Bonneville Power Administration warned that predictions this early in the season are subject to wide error bounds. Among the nuggets of information he provided were: Many of the presentations are available on the TMT web site. Click on meetings and Nov. 5 Annual Review agenda.

    Related Sites:
    Technical Management Team:

    by CBB Staff
    River Operators Assess 2003 Dam/Reservoir Operations for Fish
    Columbia Basin Bulletin, November 7, 2003

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