Passage Distributions and Federal Columbia River Power System Survival for Steelhead Kelts Tagged Above and At Lower Granite Dam
In 2012, JSATS transmitters were surgically implanted into 324 steelhead kelts captured at Lower Granite Dam (LGR) and several tributaries in the Snake River basin. Overall, 37.0% (120 of 324) of the tagged kelts successfully migrated from LGR (rkm 695, as measured from the mouth of the Columbia River) to rkm 113 (downstream of Bonneville Dam). The majority of kelts passed the dams via spillway routes (i.e., spillway weirs, traditional spill) where survival estimates were generally higher compared to all other routes of passage (e.g., juvenile bypass systems, turbines, sluiceways). The results of this study contribute to understanding the impact of hydropower on steelhead kelt migration in the FCRPS. Specifically, this study is the first to document route-specific survival since the installation of spillway weirs at many of the dams in the FCRPS. The data may be used to adaptively manage configuration and operation of FCRPS dams to maximize kelt survival.