First Year Fish Results from a Newly-Constructed Top-Spill Bypass at Wanapum Dam, Washington
The Public Utility District No. 2 of Grant County, Washington (Grant PUD) owns and operates two hydroelectric projects on the Columbia River in Washington State: Wanapum Dam and Priest Rapids Dam - Priest Rapids Hydroelectric Project FERC License No. 2114. On May 3, 2004, the National Marine Fisheries Service (NMFS - then referred to as NOAA Fisheries) issued its Biological Opinion of the effects of the proposed action on listed species, in accordance with Section 7 of the Endangered Species Act of 1973 as amended (16 USC 1531 et seq.), regarding the Federal Energy Regulatory Commission’s (FERC’s) proposed action amending Grant PUD’s existing license for the Priest Rapids Hydroelectric Project (Project) to authorize implementation of an Interim Protection Plan for listed anadromous salmonids. Subsequent to NOAA Fisheries’ issuance of the Biological Opinion and consistent with the requirements of the Biological Opinion and within the scope of its own agency jurisdiction under the Federal Power Act, on December 16, 2004, FERC issued an Order requiring Grant PUD to “implement NOAA Fisheries’ Reasonable and Prudent Alternative (Actions 1 through 25) and sections 12.2 and 12.3 of NOAA Fisheries’ Biological Opinion filed with the Commission on May 6, 2004….”In response to these requirements for downstream fish passage facilities, Grant PUD engaged in an extensive review of fish bypass concept designs to evaluate options available to increase the survival of smolts passing Wanapum Dam. Using a set of guiding principles related to the capture effectiveness, transport survival, construction costs, and construction feasibility of fish bypass options, the selection process resulted in the construction of the Wanapum Future Unit Fish Bypass (WFUFB) in early 2008. To evaluate fish responses to this newly-constructed fish bypass, in 2008 acoustically-tagged salmonid smolts were tracked as they approached and passed Wanapum Dam. The fish passage efficiency (FPE) and passage survival rate of three species of salmonid smolts that passed via the WFUFB were estimated.Data analysis of the acoustically-tagged smolts showed a FPE of 57%, 34% and 31% for steelhead, sockeye and yearling Chinook (respectfully) and a passage survival estimate of 100%, 95% and 96% for steelhead, sockeye and yearling Chinook (respectfully).