Survival and migration behavior of juvenile salmonids at McNary Dam, 2005: Final report of research

During 2005, we used radio-telemetry at McNary Dam to estimate passage and survival parameters of juvenile salmonids. During the spring migration period, two treatments were implemented: 1) 12-h spill operations with spill occurring between 1800 hours and 0600 hours, and 2) 24-h spill with spill occurring 24 hours per day. Treatments were not implemented during the summer migration period. However, a court-order was issued by Judge James Redden, U.S. 9th District Court, mandating a maximum powerhouse discharge of 50 kcfs with the remaining discharge to be spilled over the 24-h diel cycle between 1 July and 31 August 2005. Consequently, our study was conducted during two distinct periods: 1) a short period of involuntary spill for 24-h per day that occurred between 22 June and 30 June 2005, and 2) the period of court-ordered spill that was implemented after 1 July 2005.