HEC—5Q Model Applied to a Lake System in Illinois for Water Quality Evaluations

Abstract

The United States Army Corps of Engineers HEC-5Q model was applied to Lake Spring-field and two proposed lakes (Hunter Lake and Lick Creek Reservoir) to be built for supplementing Lake Springfield's water. Lake Springfield is the water supply reservoir for the city of Springfield, Illinois. Water from the lake is also used for cooling the city's power plant complex. The model was calibrated and verified on Lake Springfield using monitored data in 1986 and 1988. Eight water quality constituents were simulated. Calibration, verification, and predictions were made only for temperature, dissolved oxygen, nitrate-nitrogen, and phosphate-phosphorus. The calibrated and verified model was used to predict water surface elevations and constituent concentrations in the three lakes, individually and in combination, with meteorological and estimated flow data for a twenty-month period in 1953–1954, the most severe drought of record. The model provided a useful tool in the water quality evaluations of the three lakes.