Preventing Fish Mortality at a Large Pumped Storage Plant
Recently, concern has arisen over potential fish mortality at hydropower facilities operating on water bodies that support resident, warmwater fisheries. At the Harry S. Truman hydropower facility, initial pumpback operations resulted in mortality of fish residing in the tailrace. This facility has a generating flow capacity of 60,000 cfs and a pumpback capacity of 27,500 cfs, and because of these large flows, the Kansas City District Corps of Engineers (COE) expressed concern over long-term impacts of the project to the fisheries resources of the area. Accordingly, COE suspended all pumpback operations and initiated studies of alternative fish protection methods that could be implemented to prevent further fish losses. A number of fish diversion systems and fish barriers were conceptually designed and studied to determine their potential for cost-effective application at the Truman Project. These methods included angled diversion screens and louvers, inclined plane diversion screens, barrier nets, and bar rack systems. Laboratory studies with live fish indicated that angled screens, louvers, and bar racks operating at reduced flow rates offered the best potential for preventing mortality. Based on these findings, a field study program was initiated at the Truman Project to 1) obtain a better understanding of which fish species in the tailrace area would be most susceptible to turbine passage, 2) determine what effect various reduced flow rates would have on the susceptibility of these fish to turbine passage, and 3) estimate the level of mortality due to turbine passage. The ultimate goal of the study was to supply the data necessary to identify the potential effectiveness of the alternative fish protection systems. This paper presents a discussion of the design and operation of the alternative systems and summarizes the studies that were conducted and the way in which the data were used to identify the potential effectiveness of each system. The ultimate goal of the study was to supply the data necessary to identify the potential effectiveness of the alternative fish protection systems.