Southern Illinois lake must be drained due to condition of 82-year-old dam

The deterioration of an 82-year-old dam in southern Illinois will require that Little Grassy Lake in Williamson County be completely drained, starting later this month.

The U.S. Fish and Wildlife Service said this week that "massive flooding, erosion and deterioration" of the dam -- constructed in 1942 -- could lead to the potential failure of the spillway on the 1,000-acre lake and endanger residents downstream toward Crab Orchard Lake, and eventually the city of Carbondale. 

Officials explained that the Crab Orchard Lake Dam also has compromised gates. A failure of the spillway at Little Grassy Lake could set off a cascade of infrastructure failures that could result in loss of life and property in downstream Carbondale, Illinois and closer neighboring communities.

The dam at Little Grassy was already operating under an emergency action plan after issues were discovered in the spillway during a recent inspection, and during a two-year study by the U.S. Army Corps of Engineers to explore rehabilitating the lake's aging infrastructure.

Little Grassy is reported to be one of three reservoirs with high hazard dams within the refuge that need repair. 

After the lake is drained, officials plan to leave the gates open so the lake does not refill over time.

You can read the U.S. Fish and Wildlife press release here .

Earlier this summer it was announced the permanent closure of Little Grassy's campground and marina. The campground closed in November.