Fish Impingement at Monticello Nuclear Plant

To properly evaluate total impact of power generation facilities on aquatic systems, it is necessary to perform site specific fish impingement studies. Intake and screen approach velocities should not be averaged when considering potential screen impingement problems because of wide vertical and horizontal variation in velocity which tend to trap fish. It was estimated that 2,952 fish were impinged during 4 months of sampling with 90.9% of these comprised of black bullheads (Ictalurus melas) and black crappies (Pomoxis nigromaculatus). Distinct relationships can be found between number of impinging fish and river flow, percentage river diverted through the plant, water temperature, and the time of year. For the months of June, July, August, and September, approx 55% of all impingement occurs in June.