Farmers Conservation Alliance Flatplate Horizontal Screen: a New Technology for Screening Irrigation, Hydropower, and Municipal Water Diversions

Designing and installing fish screens on irrigation, hydropower, municipal water supplies, and industrial diversions requires technologies specifically suited for particular site conditions.  High gradient systems with high levels of sediment and organic matter are particularly difficult to effectively screen to both protect fish and supply the diverter with a reliable flow of water. Through a collaborative effort, Farmers Conservation Alliance has developed a horizontal flat plate fish screen called The Farmers Screen, with no moving parts, which is well suited to high gradient systems.  Through extensive third party biological testing and development of 22 test sites, the Farmers Screen has proven to be reliable for both fish protection and supplying a constant flow of water to water users under harsh environmental conditions.

The United States Geological Survey conducted a series of biological tests in 2009 and 2010 on an installed Farmers Screen to evaluate the effectiveness of the technology in protecting both salmon and steelhead smolts and fry.  Injury and mortality rates were evaluated as the fish passed over the screen under a variety of hydraulic conditions as well as behavioral responses to the screen. The variables that were evaluated were:  depth of water above the screen surface, sweeping velocity, and approach velocity. The behavioral tests were designed to observe the response of steelhead and coho salmon smolt and fry to the velocity transition at the leading edge of the fish screen. The test results show a clear, high level of protection for both life stages.  The Farmers Screen is currently being evaluated for the protection of Lamprey.

An analysis of installed Farmers Screen test sites shows a highly effective technology for managing sediment and debris for specific site conditions over several years of operation.  The Farmers Screen has shown to be an effective tool for fish protection as well as sediment and debris management where other technologies may not be effective.