Gas Supersaturation Monitoring Report during Corner Collector Operation at Bonneville Dam in March, 2007

摘要

To aid the downstream survival of about 7.8 million tule fall Chinook (Oncorhynchus tshawytscha) juveniles scheduled for release from the Spring Creek National Fish Hatchery on March 5 and March 9, 2007, and to continue the passage study begun in 2004, the U.S. Fish and Wildlife Service (Service) requested a Bonneville Dam Power House 2 Corner Collector (B2CC) operation that included spillway flow. An agreement with the Action Agencies (Bonneville Power Administration (BPA), and U.S. Army Corps of Engineers (Corps)) for this provision was not reached. Sufficient depth for compensation from gas supersaturation, as measured by total dissolved gas (TDG) over listed chum salmon (O. keta) redds below the Bonneville Dam project, was requested. It was calculated by Service biologists that the anticipated level of flow and B2CC operation would produce a maximum TDG level not exceeding 120% in the tailrace of Bonneville Dam, and a maximum TDG level not exceeding 105%, when compensated by water depth, at the chum and fall Chinook salmon redds located below Bonneville Dam at the Ives Island complex and across the river along the Oregon shore, principally at the Multnomah Falls area. This report summarizes the results of the 2007 March release and the monitoring for TDG during the B2CC operation.