Thumbnail Image

Evolution of the fish sorting and debris handling system at the Swift Hydroelectric Project Floating Surface Collector for juvenile salmonids

The Swift Floating Surface Collector (FSC) began operation in 2012 and was the third of eight large scale surface collectors installed in the Pacific Northwest region of the United States since 2008. Downstream fish collection and sorting at Swift Dam was a key component of the Lewis River reintroduction program that reestablished passage of anadromous salmonids past PacifiCorp’s three large hydropower dams (510 MW Lewis River Hydroelectric Project) that blocked fish passage beginning in 1931. The Swift FSC floats to accommodate reservoir fluctuation of 90 feet and attracts fish with pumped surface flows of 600 cfs. After passing through a large V-screen, fish and debris enter a fish separator system designed to separate fish by girth into fry (≤3” long), smolts (≤10” long), and adult fish (>10”). The separator system was designed as an evolution of similar systems studied on the Snake, Columbia, Yakima, and Cowlitz Rivers, and was optimized on lessons learned and to accommodate space constraints on the floating structure. Swift dam is the most upstream project on the Lewis river, so all flow entering the collector is unregulated and carries a heavy debris load. Operations staff are finding this system collects more debris than any of the other new FSC’s in the region. Several modifications to provide better debris exclusion, handling, and processing have been made and others are currently under design. These modifications also improve fish attraction, sorting, collection, and safety conditions for the operational staff. This presentation will review the original design goals and details, improvements made through 2017, highlight a new system currently under design planned to be operational in late 2018, and describe other ideas under consideration for adaptive management implementation. Lessons learned can be utilized at other downstream fish collectors with high debris loading.