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Spring Spill Curtailed,
Summer Spill Proposal Needs More Work

by Bill Rudolph
NW Fishletter, April 21, 2004

With Northwest precipitation running normal through the beginning of the new year, hydro operators were breathing easy until February, when things began to dry up. March weather turned out even worse, and by April 1, operators were nearly hyperventilating after snowpack in the Columbia-Snake Basin dropped to 70 percent of average.

The drying trend whetted appetites for a debate between fish managers and hydro operators over curtailing spill at Snake River dams that ended only a few days ago when the Corps of Engineers decided to stop spring spill April 23 at two dams on the lower Snake, only letting it slide over the spillway at Lower Monumental for up to 18 days to help an inriver passage study.

If precipitation remains normal for the rest of the year, seasonal runoff will be at 77 percent of normal, or 82.8 million acre-feet (MAF) for the Columbia Basin at the Dalles, according to the mid-month January-to-July runoff figures released April 19.

The April numbers have led to a reduced estimate for seasonal average flows at Lower Granite Dam, one that dips below the 85 kcfs threshold the Biological Opinion uses for triggering curtailment of spring spill at lower Snake dams.

"We are looking at near-drought conditions again," said Ed Mosey, spokesman for the Bonneville Power Administration. "We have the exact opposite conditions in March as we had last year."

"When flows go this low, we can barge 100 percent of the fish. That gives them the best survival rate," Mosey said.

But at the April 8 meeting of the Technical Management Team, NOAA Fisheries floated a proposal to hold off the early barging of spring chinook from lower Snake dams, citing new research that shows survival rates are lower than for wild fish barged in May. Paul Wagner of NOAA suggested ending spill and commencing barging when juvenile steelhead make up 50 percent of the smolt numbers at Lower Granite.

Wagner also cited an analysis by the University of Washington's Jim Anderson, who recommended that barging not begin until water temperatures reached 9.5 degrees C. to allow the smolts' immune systems to kick in.

Water temperatures were in the 10-degree range while the managers argued if the current hydro BiOp should be followed explicitly, since it calls for maximized barging if the seasonal average flow estimate at Lower Granite is below 85 kcfs. The Corps of Engineers' Cindy Henrikson said her agency pegs it now in the 72-77 kcfs range.

A strict interpretation would call for spill curtailment and maximized barging, Montana's TMT representative Jim Litchfield pointed out. He took issue with the possible changes in decision criteria, especially since the feds didn't bring any analysis with them to support their case.

No decision was reached by the TMT, but state and tribal salmon managers said they would get together and have a recommendation on barging ready by the afternoon of April 11. About the same time on April 8, BPA vice president Greg Delwiche was telling Power Council members that his agency was taking a serious look at curtailing spring spill and maximizing juvenile fish barging because of the deteriorating water supply forecast, citing the trigger for such action in the explicit language of the BiOp.

Fish managers submitted a request the following week to spill at three lower Snake projects until April 30, and continue other research spill operations, but NOAA Fisheries offered another proposal to spill until April 23, while continuing research spill at Lower Monumetal until the end of May.

BPA supported a proposal to end spill on April 22 at Lower Granite and Little Goose, and not implement the LoMo spill study at all this year. The agency asked the issue be raised to the policy level, and the Implementation Team met the next day to discuss the implications of various alternatives on the scheduled research. BPA's Suzanne Cooper told IT mermbers that by not spilling at the three lower Snake dams in question, the agency could save $400,000 a day.

With the Corps of Engineers ultimately responsible for making the operational decision, its representatives took the issue in-house and announced April 19 that they would only spill at the two dams for another four days, but might spill up to 18 days at LoMO for research purposes. They also said a study to test the behavioral guidance structure at Lower Granite would be postponed until next year.

The weather-induced curtailment of spill at federal dams comes on the heels of BPA's Mar. 30 announcement of its preliminary proposal to evaluate reduced spill on the Columbia River in July and ending it altogether in August. Since then, the power agency has received such a large number of comments, it announced last week it would postponed release of an amended version until April 21, with a final decision scheduled for April 30.

But federal execs didn't reach agreement at a morning meeting on the 21st and cancelled an April 23 meeting while their staffs continue to refine potential offsets and analyses in the proposal. The states or Washington and now Oregon are weighing in with their own views on how to make up for fish lost from any spill reduction. WDFW compiled a wish list of $14 million in hatchery improvements, increased flows, and habitat restoration that the agency believed had a "realistic probability" of offsetting survival losses.

Bill Rudolph and Steve Ernst
Spring Spill Curtailed, Summer Spill Proposal Needs More Work
NW Fishletter, April 21, 2004

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