Last week, Fall River Rural Electric Co-op finished installing an inflatable rubber bladder on the top of Chester Dam, completing all construction activities at the dam. The co-op expects to inflate the rubber bladder and begin full operation of the power plant at the end of March. At that point, the fish ladder at the dam and the fish screens on the canals on either side of the dam will be fully operational. The fish ladder will fully reconnect wild trout habitat below and above the dam for the first time in nearly 80 years. The fish screens will help prevent fish from becoming trapped in irrigation canals, making fall fish salvages in the canals no longer necessary!
When inflated, the rubber bladder will allow the power plant to use water that has, in the past, spilled over the top of the dam. During high flows, this spilled water was about 12-18” deep at the dam crest. The rubber bladder will capture this water, plus an additional 18” of depth, thereby raising water level in the Chester backwater about 18” over its historic depth. This will move the top of the backwater about 600 yards upstream from its historic high-water location.
Once the facility is fully operational, HFF, Idaho Department of Fish and Game, and Fall River Electric Co-op will monitor the upstream and downstream movement of fish at the dam, as well as the effectiveness of fish screens in the canals.