Progress report on fish-protective facilities at Little Goose Dam and summaries of other studies relating to the various measures taken by the Corps of Engineers to reduce losses of salmon and steelhead in the Columbia and Snake rivers

The most recent estimates (Reymond, 1971) of losses to juvenile populations of chinook and steelhead migrating downstream in the Snake River indicated that these populations may soon be reduced to critically low levels unless immediate action is taken to eliminate these losses. Tne Army Corps of Engineers initiated several actions in an attempt to reduce these losses. These actions included: (1) the support of the National Marine Fisheries Service research proposal to develop and test a collection and transportation system which involves collecting and transporting juvenile salmon and steelhead from Little Goose Dam to locations downstream from Bonneville Dam; (2) the installation and testing of prototype slotted bulkhead gates for passage of water through skeleton bays without supersaturating with N2; (3) establishment of a task force for directing load and flow control on the Columbia and Snake Rivers; and (4) continue development of a mathematical model for prediction and possible control of nitrogen gas supersaturation. This report summarizes progress by the National Marine Fisheries Service relative to the foregoing actions. Specific areas of research covered are: the traveling screen and orifice bypass tests, transportation studies, surveys of dissolved nitrogen concentrations, and related fish survival studies. Contract no. DACW68-71-C-0093