The Corps Water Management System (CWMS) includes four interrelated models to assist with water management for the basin:
- GeoHMS (Geospatial Hydrologic Modeling Extension)
- ResSIM (Reservoir System Simulation)
- RAS (River Analysis System)
- FIA (Flood Impact Analysis)
The Kaskaskia River basin is the second largest basin in the state of Illinois, covering approximately 5,790 square miles. The headwaters are in the center of Champaign County, and the basin flows in a southwesterly direction. The basin drains to the Mississippi River, and the outlet is just upstream of the city of Chester, Illinois. The basin is roughly 175 miles long and has an average width of 33 miles. The Kaskaskia River has a very sinuous channel with low banks and a small slope. During times of heavy rains, the valleys in the basin can be subjected to serious flooding. The primary land use in the basin is agriculture. There are some urbanized areas in the watershed, including the St. Louis Metro East, Champaign, Vandalia, and other small towns spread throughout the basin.
There are two reservoirs constructed and operated by the US Army Corps of Engineers in the watershed: Lake Shelbyville and Carlyle Lake. Both dams are located on the main stem of the Kaskaskia River and are operated in tandem by the St. Louis District. The purpose of the reservoirs are to provide flood damage reduction, to create recreational opportunities, to augment water supply, to enhance water quality, to augment flows for navigation on the lower Kaskaskia River, and to provide fish and wildlife conservation. There is a Lock and Dam at the lower end of the Kaskaskia River, located approximately one mile upstream of the confluence with the Mississippi River. This structure provides sufficient depth for the navigation channel, which runs from the mouth to Fayetteville, Illinois, approximately 36 miles upstream. The Kaskaskia River was straightened and widened to provide for consistent navigation through this stretch. Upstream of Fayetteville the Kaskaskia River returns to its natural state.