Radio telemetry equipment will be used to determine grass carp movement. Attraction flows have been used successfully for decades at the downstream ends of fish ladders to attract adult salmonids to fish ladder entrances. Similar hydraulic concepts for simulating a turbulent stream have generally not been implemented to divert juvenile migrants into dam bypasses and away from damaging turbine intakes. Turbulence appears to be a feature of normal flow in natural rivers that guides and assists juvenile salmon migration. Enhanced turbulence at bypass entrances and within bypass channels could also improve the effectiveness of juvenile salmonid guidance and retention in the bypasses.
Behavioral guidance includes, at least in principle, both repulsion and attraction.
This paper suggests more attention be given to their use together. Research in the 1940s and 1950s with adult salmon and prototype fish ladders emphasized attraction. As a result, attraction flows to entice fish to fish ladder entrances are a usual feature of adult dam bypasses. In contrast, techniques for repulsion have dominated consideration of ecological risks from water intakes in both the hydropower and steam electric utility industry. Thus, strobe lights, sound, bubble curtains, electric fields, and the like have been evaluated as ways to repel fish from intakes.