Project goals and objectives:
Evaluate the potential effectiveness of an electric barrier at reducing walleye escapement from reservoirs. Laboratory experiments were used to compare walleye behavior, escapement, and mortality using four pulse (0, 0.3, 0.5, and 0.8 ms) and three voltage (0, 60, and 80 V) settings.
Fish entrainment through dams, hydroelectric projects, or into cooling water intakes has been shown to have negative impacts on fish populations. In Iowa, walleye escapement from Rathbun Lake can approach 30% annually with an associated large economic cost. Section 316(b) of the Clean Water Act has required that “best technology available” be used to minimize adverse environmental impacts resulting from operation of cooling water intake structures. Thus, evaluations of barriers to reduce walleye escapement are needed. Several different types of nonphysical barriers have been employed, such as constant light, strobe lights, underwater sound, bubble curtains, electrical current, or a combination of the above. A recent barrier evaluation found that a sound-air-light barrier was minimally effective at reducing walleye escapement. The use of electric barriers has been successful at reducing movement of fishes for over 60 years. However, few formal evaluations currently exist that assess their ability to successfully deter fish movements.
This project was completed by Michael J. Weber, Mark Flammang, and George Scholten. Click here to read more about this research.