With efforts to keep fish out of irrigation ditches, irrigators in the Salmon Region who divert water from rivers and streams are asked to call Idaho Department of Fish and Game’s Anadromous Fish Screen Program at 208-756-6022 several days in advance of shutting off their ditches for the season.
Irrigators are also asked to ramp down their flows over several days before turning ditches completely off. The gradual decrease in flow stimulates fish to migrate out of the irrigation system. Irrigators are encouraged to leave a minimal flow of 50 inches (1 CFS) in the ditch to allow time for Fish and Game to collect any stranded fish. If requested, Fish and Game can turn down the headgate the rest of the way after any stranded fish are removed.
Fish and Game’s screen program currently operates and maintains over 270 fish screens that allow fish trapped in irrigation ditches to return to the stream or river. The screen program, water users, and landowners have been working together to prevent the loss of fish into area ditch systems for well over 60 years.
The success of this program was measured with a study that began in 2003 to count fish as they were returned back to the river after being diverted. It was found that in the Lemhi River, up to 88 percent of all migrating juvenile Chinook salmon are diverted into at least one ditch system as they migrate to towards the ocean. Through the screening efforts, all of these fish are safely returned to the river.
Fish screens not only prevent the loss of Chinook salmon, but steelhead, sockeye salmon, bull trout, cutthroat trout, rainbow trout, and mountain whitefish are safety returned as well.