The Lake Sangchris Study

Case History of an Illinois Cooling Lake

Abstract

Under contract with Commonwealth Edison Company, the Illinois Natural History Survey studied this cooling lake ecosystem intensively from August 1973 through August 1977 to determine the effect of the thermal discharge and combustion byproducts on the local environment. Investigations included detailed studies of water quality, plankton, aquatic macrophytes, clams, benthos, fish, fish harvest or creel, waterfowl, trace metals, and pesticides. Some studies (water quality, benthos, clams, and aquatic macrophytes) were terminated in 1976, and others were initiated to consider the distribution of larval fishes in the cooling loop and the effect of the impingement and entrainment of fish by the power plant.

In June 1975 , the Illinois Natural History Survey received additional support from the Electric Power Research Institute (EPRI) of Palo Alto, California, to expand investigations at Lake Sangchris. The expanded work consisted of three parts: (1) a study of the relationship between the fisheries and the physicochemical conditions associated with power production, including fish temperature preferences, potential dangers to the biological system, benefits to plant and animal communities, and causes of environmental degradation associated with power production; (2) construction of a fish production model from the large accumulation of physical-chemical-biological data; and (3) a comparison of fish production in Lake Sangchris with that of Lake Shelbyville, a nearby flood control reservoir. This work has been completed, and a four-volume final report: Evaluation of a Cooling Lake Fishery, has been published by EPRI (1979-1980). However, those investigations cannot be completely separated from the work supported by Commonwealth Edison and reported here.

The investigative work was carried out by an interdisciplinary team of specialists. Administration and overall coordination of the project were handled at the Illinois Natural History Survey headquarters in Urbana, while field activities were coordinated through a field station at Kincaid, a few miles from the lake. Most of the fishery biologists were based at the field station; other team members were based in Urbana where more extensive laboratory and analytical facilities were available.