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Lower Snake Operations Aimed at Bypass / Transport Research

by Mike O'Bryant
Columbia Basin Bulletin - April 26, 2002

Operations at Lower Monumental Dam on the Snake River are changing to accommodate research studies that ultimately will help regional biologists compare the success of transporting juvenile salmon and steelhead versus that of full flow bypass of the fish through dams.

Faced with erosion of the spilling basin at the dam that precludes spilling water this year, the National Marine Fisheries Service initially proposed operations that would run juvenile salmon and steelhead through the dam's bypass system through May 1 and then begin collecting fish full time to transport on barges.

Instead, Paul Wagner of NMFS notified the Technical Management Team at this week's meeting that the operation would not satisfy research requirements and would need to be changed.

"This year presents an opportunity to get insight" into the benefits of both transportation and full flow bypass, Wagner said. Combined with studies in 1999 and 2000, this year's research could "get us closer to the truth and help us make longer term decisions."

Operation at the dam is not according to the NMFS 2000 biological opinion, he said, but that is because of the spilling basin erosion, which is due to be repaired before 2003 spill begins. The BiOp calls for collection at the dam from the beginning of the spring spill season. However, NMFS and TMT had determined in early April that sweeping fish through the bypass system in the early part of the spill season and shifting to transportation May 1 would result in higher survival. An October 2000 smolt transportation study by NMFS scientist Michael Scheiwe showed greater smolt to adult survival for in-river fish with spill until May 1 and greater survival for barged fish after May 1 to mid-May.

"We're concerned about all these research projects," said Ron Boyce, of the Oregon Department of Fish and Wildlife. "They may compromise survival of the fish. We support them, but let's make sure we look at the best thing to do for this year's migration. It's not a good idea to pit one research project against another."

Wagner said the new operation plan, which was decided by conference call a day after the TMT meeting, will satisfy the research plan and take advantage of thousands of juvenile salmon and steelhead in the system tagged with either PIT tags or radio telemetry tags. As part of the transportation study, Snake River hatcheries run by the state of Idaho and the Nez Perce have tagged in excess of 100,000 juvenile chinook salmon, he said. NMFS is tagging an additional 50,000 wild chinook salmon at Lower Granite Dam and about 70,000 wild steelhead smolts.

"There are a lot of sources of fish in the system for system survival and transportation studies," Wagner said. Some percentage of the fish are expected to return to the river as adults in 2004-05 when biologists can begin to measure the success of transportation or of bypass with these fish.

The agreement is to provide full flow bypass at Lower Monumental Dam for one day and to alternate for two days with collection and barging of juveniles.

Related Sites:
Technical Management Team

Mike O'Bryant
Lower Snake Operations Aimed at Bypass / Transport Research
Columbia Basin Bulletin, April 26, 2002

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