Concurrent Sessions A: Nature Like Fishways - Guiding Downstream Migrants Into Fish Bypasses or Nature-Like Fishways With A Flow Velocity Enhancement System
There are many designs for downstream fish bypasses at dams and nature-like fishways, but attracting the downstream migrants to the safe routes rather than hazardous ones has been a problem. Hydraulic migration cues generated by bulk flows leading to turbine intakes or irrigation withdrawals, for example, often overwhelm the cues generated by smaller flows leading to bypasses. A Flow Velocity Enhancement System (FVES) has been developed to induce a plume of mildly turbulent flow simulating river hydraulics, which can guide migrants to bypasses or other collection points. The system successfully guided sonic-tagged Chinook salmon smolts at the head of Riffe Lake in the Cowlitz River, Washington, in a zone of sluggish and variable flows. Feasibility tests were conducted in the Netherlands for guiding silver eels away from a pump station on a canal system that raises water from farmland located below sea level. Conceptual designs have been prepared for application of the FVES to the entrances of artificial, nature-like fishways. The FVES and its test applications are described. Additional locations for testing and application are being solicited
