The Nechako Reservoir was created in 1953 to supply water to the 896 MW Kemano Hydroelectric Generating Station, which provides power to Rio Tinto’s aluminum smelter at Kitimat. The Skins Lake Spillway is located approximately 200 km west of Prince George, British Columbia. The spillway regulates the reservoir water level and is the only flood discharge control structure. Due to continuing erosion concerns within the spillway plunge pool threatening the reliability of the spillway and water retaining structures, Rio Tinto proceeded with major repairs to the plunge pool walls and roller-compacted concrete slab.

Klohn Crippen Berger applied creative design and construction planning for the plunge pool rehabilitation to account for the small construction window and downstream flow requirements. Project risks were reduced by dewatering the plunge pool the year prior to construction to re-assess the work, determine the stoplogs leakage to be managed, confirm time to perform fish recovery, and confirm the reliability of the bypass system.