Studies to evaluate the effectiveness of vertical barrier screens and outlet flow-control devices at McNary Dam, 1997

During the 1997 spring and summerjuvenile salmonid outmigrations, descaling evaluations and orifice passage efficiency (OPE) tests using a mark and release method were conducted at McNary Dam. Descaling and OPE tests were conducted in Turbine Units 4 and 5 which were equipped with extended-length submersible bar screens (ESBSs) and inlet flow vanes. Tests evaluated two vertical barrier screen (VBS) designs (a prototype test VBS and the existing VBS), and a lowered vs. raised position for an outlet flow-control (OFC) device. During spring, turbine loads were alternated daily between 60 and 75 MW in both test units; during summer tests, Unit 4 was operated at 60 MW and Unit 5 was held near 80 MW. In addition, dip-basket efficiency tests were conducted during the spring season. Contract no. E86970083