Fine sediment deposition from Clark Canyon Creek has affected fisheries in the Beaverhead River during years when peak flow releases from Clark Canyon Dam are insufficient to transport the sediment from this tributary. The fine sediment settles in the Beaverhead River, affecting the trout fishery downstream from the dam. The Bureau of Reclamation conducted a study resulting in an annual program of short-duration, high-flow releases from Clark Canyon Dam to flush fine sediments from the stream bed and improve habitat conditions for trout.
The East Bench Unit Joint Irrigation Board, Bureau of Reclamation, and Montana Fish, Wildlife & Parks worked collaboratively to release a flushing flow from Clark Canyon Reservoir between May 4th and May 8th in 2017 to mobilize the fine sediment. This management action was developed and made possible by the Beaverhead Watershed Committee and their longstanding work and dedication towards developing local, collaborative solutions to watershed health issues and a strong willingness by the East Bench Unit Joint Irrigation Board and the Bureau of Reclamation to partner in finding unique solutions to difficult problems. Montana Fish, Wildlife & Parks continues to work with the Bureau of Reclamation, irrigators and the Beaverhead Watershed Committee to reserve reservoir water to use for a flushing flow when needed. In addition, during years with enough stored water in the reservoir, we run a “spring pulse” through the river to mimic spring runoff. Click here to view Beaverhead Flushing Flow Report