Dean A. Brege

Juvenile Salmonid Guidance at the Bonneville Dam Second Powerhouse, Columbia River, 1983–1989

Abstract Studies of fish guidance with submersible traveling screens (STS) were conducted at the Bonneville Dam second powerhouse, Columbia River, during the 1983-1989 seaward migrations of yearling (age-1) and subyearling (age-0) salmonids Oncorhynchus spp. In 1983, the initial measurements of fish guidance levels were less than 25% for yearling and subyearling chinook O. tshawytscha and coho O. kisutch salmon and approximately 33% for steelhead O. mykiss, compared with expected levels greater than 70% for all species. Modifications based upon hydraulic models and field research were made to the trashracks, STSs, and face of the powerhouse. With these modifications, yearling chinook and coho salmon guidance levels greater than 75% were sometimes attained, but maximum steelhead guidance was less than 70%. Guidance of subyearling chinook salmon during the spring migration was as high as 60% but during the summer migration remained below 30%. Even with major modifications to the second powerhouse, fish guid...

Canister for Releasing Marked Fish at Depth in Hydroelectric Dam Gatewells and Forebays

Abstract At Pacific Northwest hydroelectric dams, surface containers or hose systems have been used to release marked juvenile Pacific salmon Oncorhynchus spp. for fish passage studies. Because these release methods introduce marked fish to unknown depths and hydraulic conditions, they may compromise study results. We constructed a canister and frames for releasing marked fish at predetermined depths and locations in the gatewells and forebays of hydroelectric dams. The canister performed as anticipated, avoiding injury to fish and allowing them to acclimate to depth prior to release. Acclimation is accomplished by slowly lowering the canister to the desired depth and holding the canister for a period of time before release. A total of 1,000 yearling and subyearling chinook salmon O. tshawytscha were released with this canister over a 2-year period in studies of guidance and orifice passage systems. About 98% of these fish were recaptured, with no injury or descaling attributed to the release canister. Th...

An Air-Lift Pump for Sampling Juvenile Salmonids at John Day Dam

Abstract An air-lift pump system was designed and constructed to sample juvenile salmonid accumulations in the turbine-intake gatewells of John Day Dam on the Columbia River. A funnel concentrated fish into a 30.5-cm-diameter thin-walled pipe into which compressed air was delivered. Fish were lifted from water depths of 14–25 m to heights of 1–7.3 m above the water surface. With a 14-m Submergence and 1-m head, the Sampling system operated continuously, dependably, and economically, providing hourly estimates of salmonid passage with little or no injury to fish.

Management Briefs: An Anchor System for Periodic Retrieval of Current Meters from Fixed Locations

Abstract An inexpensive anchor system was designed and used at numerous sites in the forebay of John Day Dam for the purpose of charting river currents during outmigration of juvenile salmonids. This system allowed for the removal of a current meter from the water for periodic maintenance and data retrieval while the anchor remained in a stationary position on the bottom. The anchor system functioned satisfactorily during the 2-year study.