Fish Passage Center ; Columbia Basin Fish and Wildlife Authority, 2001 Annual Report PDF Download

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Languages : en
Pages : 316

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Extremely poor water conditions within the Columbia River Basin along with extraordinary power market conditions created an exceptionally poor migration year for juvenile salmon and steelhead. Monthly 2001 precipitation at the Columbia above Grand Coulee, the Snake River above Ice Harbor, and the Columbia River above The Dalles was approximately 70% of average. As a result the 2001 January-July runoff volume at The Dalles was the second lowest in Columbia River recorded history. As a compounding factor to the near record low flows in 2001, California energy deregulation and the resulting volatile power market created a financial crisis for the Bonneville Power Administration (BPA). Power emergencies were first declared in the summer and winter of 2000 for brief periods of time. In February of 2001, and on April 3, the BPA declared a ''power emergency'' and suspended many of the Endangered Species Act (ESA) and Biological Opinion (Opinion) measures that addressed mainstem Columbia and Snake Rivers juvenile fish passage. The river and reservoir system was operated primarily for power generation. Power generation requirements in January through March coincidentally provided emergence and rearing flows for the Ives-Pierce Islands spawning area below Bonneville Dam. In particular, flow and spill measures to protect juvenile downstream migrant salmon and steelhead were nearly totally suspended. Spring and summer flows were below the Opinion migration target at all sites. Maximum smolt transportation was implemented instead of the Opinion in-river juvenile passage measures. On May 16, the BPA Administrator decided to implement a limited spill for fish passage at Bonneville and The Dalles dams. On May 25, a limited spill program was added at McNary and John Day dams. Spill extended to July 15. Juvenile migrants, which passed McNary Dam after May 21, experienced a noticeable, improved survival, as a benefit of spill at John Day Dam. The suspension of Biological Opinion measures resulted in very poor in-river migration conditions in 2001. Up to 99% of Snake River yearling chinook and steelhead were transported from the Snake River collection projects. Approximately 96% of Snake River juvenile sub-yearling fall chinook were transported. Of Mid-Columbia origin yearling chinook, 35% were transported, of steelhead 30% were transported and of sub yearling chinook, 59% were transported. Based upon data collected on the run-at-large, the juvenile survival to Lower Granite Dam of wild and hatchery yearling chinook and wild and hatchery steelhead were the lowest observed in the last four years. In 2001, as the result of the lowest observed flows in recent years, travel times through the hydro system for spring chinook yearlings and steelhead was approximately twice as long as has been observed historically. Juvenile survival estimates through each index reach of the hydro system for steelhead and chinook juveniles was the lowest observed since the use of PIT tag technology began for estimating survival.