From the Memo:
"...drought conditions in the Okanagan Lake region this year have resulted in lower than normal lake elevations and this poses a threat to the eggs of beach spawning kokanee. In November 1987, C.J. Bull, Fish and Wildlife, had requested that the present lake discharge of 175 cfs into the Okanagan River be reduced to 100 cfs. This would reduce the winter drop in lake elevation from 6 inches to 3.5 inches, thereby reducing the dehydration and freezing risk to kokanee eggs by up to 30%. To address this problem, a survey was carried out November 19-20, 1987 to determine what flow release from Okanagan lake would allow Okanagan lake kokanee downstream and Okanagan River sockeye eggs to share the same risks of dewatering and/or freezing.
Two sites were chosen to resolve the problem; a prime kokanee beach spawning site at Carrs Point on Okanagan Lake, north of Kelowna, and a representative sockeye spawning area on the Okanagan River near Oliver. The beach at Carrs Point had a gentle slope of 1:22.7. Flow releases from the Vaseux Lake dam were manipulated - lowered to 100 cfs for 16 hours - to measure the areal extent of exposed sockeye redds at 175 cfs and 100 cfs."