Water Supply from Shelbyville and Carlyle Lakes and Their Optimal Joint Operation

Abstract

The U.S. Army Corps of Engineers, St. Louis District, has been regulating Lake Shelbyville and Carlyle Lake on the Kaskaskia River in Illinois for recreation and flood control since completion of the dams in 1969 and 1967, respectively. These lakes will soon have to be regulated for the multiple purposes for which they were built, that is, recreation, flood control, water supply, and navigation. The state of Illinois has a reserve storage capacity of 25,000 ac-ft in Shelbyville and 33,000 ac-ft in Carlyle for meeting future water supply requirements. Optimal operating policies for the joint regulation of Shelbyville and Carlyle lakes for various levels of navigation and water supply requirements have been derived from more than 10,000 system simulation runs made with historical and synthetic data. The optimal operation rules indicate a rise in rule levels with increase in navigation and water supply requirements. The joint regulation can be updated with development of navigation and water supply to obtain the maximum benefits. When state and federal storages are not considered separate and distinct, and the total storage is regulated in the best interest of all purposes as done in deriving the optimal operating rules, the minimum lake levels reached are higher than the dead storage pool elevations even with 200 cfs (130 mgd) water supply withdrawal and full navigation.