Charles C. Coutant, Oak Ridge National Laboratory, P. O.
Box 2008, MS-6036, Oak Ridge, Tennessee 37831-6036; Voice 423-576-6830;
FAX 423-576-3989; E-Mail coutantcc@ornl.gov
Keywords: hydropower, bypass, turbulence, attraction, FERC
Induction of mild turbulence and increased water velocity in slowly
moving water of dam forebays has been proposed to attract downstream-migrating juvenile
salmonids in the Pacific Northwest to dam bypasses. Bypasses prevent damages to migrants
in hydropower turbines, one of the most vexing problems for hydropower relicensing. The
concept may also be applicable to juvenile anadromous alosids (American shad, blueback
herring, alewife) in southeastern coastal rivers. Hydraulic concepts for simulating a
naturally turbulent stream have been used to attract upstream-migrating adults to ladders
and lifts, but not for enhancing the "opportunity for discovery" of fish bypass
entrances in dam forebays by downstream migrants. Turbulence can be enhanced near bypass
entrances by passive (using existing flow momentum or head directed by vanes) and active
(pumped water jets or propellers) methods, which can be tailored to specific locations.
Although sound in theory, the concept needs to be tested and evaluated both experimentally
and at hydropower sites
