316(b) and Quad Cities Station,Commonwealth Edison Company

Quad Cities Station is a 1630 MW_e dual reactor facility located on the Upper Mississippi River approximately 30 miles north of Davenport, Iowa and Rock Island, Illinois. As designed, the Station utilizes river water at the rate of 2270 cfs in an open-cycle mode of operation. From the 316(b) perspective, numerous agencies and intervenors expressed major concern regarding the potential adverse impacts of open-cycle entrainment and impingement effects on the River’s highly valued and diverse fishery. As a result, the fishery has been monitored continuously since 1971 through field surveys directed at measurements of community composition and relative abundance, as well as fish impingement surveys of the Station’s intake. From 1972 to 1983 the Station operated in a closed-cycle or partial closed-cycle mode.Regulatory relief and intervenor approval for open-cycle operation were not granted until 1984, following several years of intensive studies directed at entrainment/impingement and methods to reduce impingement. Beginning in 1978, the freshwater drum was selected as the indicator species most likely to manifest changes in population characteristics potentially resulting from open-cycle operation. Population levels (numbers and biomass), growth, fecundity, sex ratios and survival were all monitored to determine if compensatory responses occurred within the population following increases in impingement under open-cycle operation. Included in the agreement that allowed the return to open-cycle operation was a commitment to construct and operate a fish production facility to mitigate for potential impacts.After 14 years of monitoring under open-cycle operation, there have been no measurable changes in the local fishery and, specifically, none within the freshwater drum population. Naturally occurring environmental conditions have more profound influences on this dynamic and resilient fishery than operation of a large generation facility. Station operation is relatively constant from year to year and impingement monitoring may actually be the most accurate monitoring activity. Fluctuations in annual impingement projections are reflections of conditions within the river and the fishery’s response to them. Increases or decreases in fish numbers impinged at the Station in any given year are primarily due to fluctuations in the fishery and the effects of existing environmental variables and not to Station operation. The fishery fluctuations are reflections of conditions within the river and the fishery’s response to them.