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BIOP Interpretation Leads to
Snake River Spill for Fish

by Mike O'Bryant
Columbia Basin Bulletin - April 4, 2003

Columbia River Basin power and fish managers decided Thursday that spill at hydroelectric projects as well as transportation of juvenile salmon around dams would begin dams this week.

The decision came after vigorous debate at multi-agency Technical Management Team and higher level Implementation Team meetings over how to interpret criteria that triggers lower Snake River spill set in NOAA Fisheries' 2000 biological opinion of the Federal Columbia River Power System.

The first spill began at Lower Granite Dam Thursday evening and spill at other dams will begin in two-day intervals.

The BiOp calls for spill to begin if the April 3 through June 20 water volume forecast for the lower Snake River is at least 16 million acre feet and if the estimated seasonal average flow at Lower Granite Dam is 85,000 cubic feet per second or greater. Although the criteria have been set since the NOAA Fisheries 1995 BiOp, this is the first year that the actual conditions have been so close to the criteria that a ruling was needed.

TMT debated the issue Wednesday, finally deciding it was a policy issue and sent the decision to IT.

The most recent lower Snake River water supply forecast by the Northwest River Forecast Center is 16.9 maf. Based on that forecast, the U.S. Army Corps of Engineers determined that the seasonal average flow would be 81.2 kcfs. However, based on another April 1 Corps calculation, the water supply would be 17.2 maf, with a seasonal average flow of 82.3 kcfs. In both cases, the flow target would not be met.

However, fisheries managers suggested that in light of river and fisheries conditions, flexibility is needed. With a huge run of chinook juveniles already showing up at Lower Granite Dam, with increased turbidity that protects the migrating salmon from predation and with new, albeit controversial, evidence that spill early in the season is better for juveniles than is transportation of juveniles on barges, IT agreed and decided that some degree of flexibility in interpreting the BiOp is warranted.

"While we acknowledge that Action 40 in the BiOp implements voluntary fish spill at 85 kcfs, we believe that flows are so close that we should begin spill now," said Jim Ruff of NOAA Fisheries and chair of IT. "Given the fact that the fish are moving and we're expecting a record 1.7 million chinook juveniles and a large outmigration of steelhead to pass the dams this spring, we think the conditions are such that we should spread the risk and believe that action is within the spirit of the BiOp."

The previous 11-year average run of chinook juveniles is in the range of wild 827,000 fish, according to Steve Pettit, Idaho Fish and Game. "The juvenile run is at least twice that this year," he said.

"Start spill now and spread the risk," said Bob Heinith of the Columbia River Inter-Tribal Fish Commission. "We're seeing an early and large migration all over the basin." He said biologists are also expecting a record 40 million chinook to emerge from the gravel along Hanford Reach on the mid-Columbia River.

Ruff added that new research that looks at barging fish versus leaving them in the river is showing an early benefit for leaving the fish in the river even at river flows below 85 kcfs. Still, he said, "If we continue this precipitation and snow, we think we will end up above 85 kcfs anyway."

Pettit said that the mountains in western Idaho had received 20 to 30 inches of new snow and expected more, and that the Salmon River and Clearwater River snowpacks were now at near normal levels. Flows at Lower Granite Dam rose from about 60 kcfs Wednesday morning to over 70 kcfs Thursday morning this week. Some of that was due to an increase in flows at Dworshak Dam to nearly 10 kcfs as a flood control precaution. The RFC most recently predicted Dworshak water supply at 91 percent of normal, a dramatic increase from its early March estimate. Inflow to the dam through March was at 140 percent of normal, according to the Corps' Cindy Henriksen.

Other forecasts around the basin are 83.1 maf at The Dalles Dam, January through July, which is 77 percent of normal and 52.4 maf at Grand Coulee Dam, which is 83 percent of normal. The RFC will release its April final water supply forecast April 8.

"We're willing to start spill," Jim Athern of the Corps told IT. "But we don't view what we're doing now in 2003 as a precedent for future years."

He pointed to the NWRFC's new water supply forecast due out next week, saying that TMT, which is responsible for making in-season decisions regarding dam operations as they impact fisheries, should revisit the decision next week and throughout the spring spill season to ensure there is enough water to continue or to cease spill. He added that if transport data shows less of a benefit for spill later in the season, then TMT should have the flexibility to turn spill off.

The Bonneville Power Administration's Suzanne Cooper also supported the spill decision, but said her agency is in a unique situation.

"Bonneville is likewise in a unique and persistent financial situation that is not expected to be remedied in the near future," Cooper said. "This (referring to the spill) is a cost to us, but we recognize this is a part of our obligation under the ESA (federal Endangered Species Act)."

The NOAA Fisheries Science Center's John Williams presented the new transportation data to TMT at its meeting two weeks ago. The data showed a slight benefit of providing spill and leaving migrating juveniles in the river early in the season.

"The 1995 through 1998 data questions the value of transportation early in the spring season," Paul Wagner told IT members. "Another conclusion from the data is that there is value in providing spill when flows are low. If you're going to provide a spread the risk action, then early in the season is the best time to do it." However, the results of the studies are controversial and uncertain due to the wide confidence bands, or margin of error, assumed in the studies.

Jim Litchfield, representing Montana, said the data regarding transportation and spill is too uncertain.

"The confidence intervals are tremendously broad in the research. To draw conclusions from them is speculative," Litchfield said. "I'm not convinced the within-season SARs (smolt to adult ratio) are something we understand yet. At least wait until flow is at 85 kcfs. That's the definition in the biological opinion that defines good in-water conditions," he said.

Wagner said the Science Center data shows that flows aren't the critical factor in deciding when to begin spill and leave fish in the river, but that timing is. "The current thinking is that there is no benefit to early transportation because the fish get to the estuary too early," he said. Citing other studies, he said the fish move into the ocean too early, but the offshore upwelling that results in highly productive ocean conditions isn't available until later in April.

"We acknowledge the uncertainty in the data, but the data is leading us to believe that the fish are better off in river at this time," Ruff said. "We're asking for a big shift in operations based on this new information." He said that much more research needs to be done and that new criteria may be needed to flesh this out in the BiOp.

Spill began Thursday, April 3, at 6 p.m. at Lower Granite Dam. It will begin at Little Goose Dam on April 5, at Lower Monumental Dam on April 7, and at Ice Harbor Dam on April 9.

Related Sites:
Implementation Team:
Technical Management Team:

Mike O'Bryant
BIOP Interpretation Leads to Snake River Spill for Fish
Columbia Basin Bulletin, April 4, 2003

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