Juvenile Salmonid Passage, Distribution, and Survival at Foster Dam; Pairing Hydroacoustic and Radio Telemetry Study Results

Foster Dam, operated by the U.S. Army Corps of Engineers, Portland District, is located in the Willamette Valley on the South Santiam River, OR.  Fisheries research at this dam is focused on enhancing downstream fish passage for threatened populations of Upper Willamette River Spring Chinook salmon (Oncorhynchus tshawytscha) and Upper Willamette River steelhead (O.  mykiss).   The Pacific Northwest National Laboratory conducted a yearlong fixed-location hydroacoustic evaluation at the dam to provide baseline data on downstream passage rates, timing, and distributions.  Results from this study indicated juvenile-sized fish passed the dam via the turbine units in high proportions compared to other routes. A fish weir, located in a spill bay, passed more fish than other available routes during summer months when the reservoir was full. Additionally, steelhead kelt moving downstream did so via the fish weir.  Although the spillway itself was not an overly effective route of passage, migrating salmonids utilized this route of passage in moderate proportions.  These findings informed the second stage of research at Foster dam; a radio telemetry survival study is being conducted in 2015 and the results from both studies will be presented at the American Fisheries Society national meeting.