Fish Passage at the Prototype Surface Bypass and Collector at Lower Granite Dam

摘要

The objective of this study was to use fixed-location hydroacoustic techniques to estimate fish passage rates and efficiencies at a prototype surface bypass and collection (SBC) system. The prototype SBC was studied in spring 1996 at Lower Granite Dam on the Snake River, Washington State. This paper briefly describes the single-beam hydroacoustic methods, and reports on biological performance of the SBC in terms of passage rates and derived variables. The 1996 data show that fish used the SBC. All three SBC entrance configurations showed moderate success, depending on the evaluation parameter, although none appeared "optimal." Important questions and recommendations resulting from these findings are discussed in relation to surface flow bypass development efforts at mainstem dams where anadromous fish passage is an issue.