REND LAKE, Ill. (AP) — The U.S. Army Corps of Engineers says Rend Lake in southern Illinois was crucial to alleviate flooding on the Big Muddy River and Casey Fork River when water levels rose in recent weeks. Rend Lake is the state’s second largest man-made lake. The Army Corps of Engineers says the lake was built primarily as a drinking water source and to provide downstream flood reduction. Corps park ranger Cassie Magsig tells The (Carbondale) Southern Illinoisan that water rushing through the lake gets held back, and the rush gets slowed. Gov. Bruce Rauner issued disaster declarations for more than 20 counties in Illinois after flooding in the last month. The lake was completed in the 1970s and supplies water to more than 60 communities in 10 counties.