Watersheds of Illinois - 1996

25. Lower Kaskaskia River Watershed

The Lower Kaskaskia River Watershed covers a total of 1,016,985 acres in Madison, Bond, Clinton, St. Clair, Monroe, Randolph, Perry, and Washington counties. The largest cities in the watershed are Belleville (42,806), O'Fallon (16,073), and Mascoutah (5,511). Major streams which comprise the Lower Kaskaskia River Watershed include Horse Creek, Richland Creek South, Silver Creek, Mud Creek, and Sugar Creek. A total of 840 stream miles were assessed on the Lower Kaskaskia River and its tributaries. Overall resource quality is "good" on 199 stream miles (24%), "fair" on 629 stream miles (75%), and "poor" on 12 stream miles (1%). The primary causes of water quality problems are nutrients and organic enrichment (low dissolved oxygen) due to the effects of agricultural runoff, hydologic/habitat modifications, and point sources. A total of eight lakes covering 2,602 acres were also assessed in the watershed. Overall resource quality is "good" on 10 acres (0.1%) and "fair" on 2,592 acres (99.9%). The primary causes of water quality problems are siltation and suspended solids attributed to agricultural runoff.

Kaskaskia River

A total of 84 stream miles of Kaskaskia River (O) were assessed in the Lower Kaskaskia River Watershed. The overall resource quality of all 84 stream miles was rated as "fair." Causes of pollution include nutrients, and siltation attributed to agriculture and hydrologic/habitat modifications.

Silver Creek

A total of 81 stream miles were assessed on Silver Creek (OD). Of the total, 36 miles were rated as "good," and the overall resource quality of 45 stream miles was rated as "fair." Causes of pollution include nutrients and siltation attributed to agricultural runoff.

Sugar Creek

All of the 37 stream miles assessed on Sugar Creek (OH) were rated as "fair" in terms of the overall resource quality. Siltation and organic enrichment (low dissolved oxygen) were the primary causes of pollution attributed to agricultural runoff.

Coulterville City Reservoir

Coulterville City Reservoir (ROV), located in Randolph County, is managed by the city of Coulterville as their public water supply. The lake was created by damming a tributary of Muddy Creek in 1939. The lake has a surface area of 24 acres and receives its water from a 781 acre watershed. The overall resource quality of the lake is considered "fair." Causes of pollution to the lake include nutrients, siltation, suspended solids, and noxious aquatic plants. The primary source of pollution is agricultural runoff.

Baldwin Lake

Baldwin Lake (ROW), located in Randolph County, is a privately-owned, public access lake (Illinois Power Company) that is managed by the Illinois Department of Natural Resources. The lake was created in 1968. This "perched" or diked lake is 1,967 acres in size. To maintain water levels, water is pumped into it from a nearby tributary of the Kaskaskia River. The overall resource quality of the lake is considered "fair." Causes of pollution to the lake include suspended solids and organic enrichment (low dissolved oxygen). The primary source of pollution is agricultural runoff.

Highland Silver Lake

Highland Silver Lake (ROZA), located in Madison County, is a publicly-owned lake managed by the city of Highland as a public water supply and recreational resource. The lake was created in 1962 by digging out a lowland area and damming East Fork of Silver Creek. The lake has a surface area of 550 acres and receives its water from a 31,000 acre watershed. The overall resource quality of Highland Silver is considered "fair." Causes of pollution to the lake include siltation, nutrients, suspended solids, and organic enrichment (low dissolved oxygen). Primary sources of pollution include agricultural runoff and shoreline erosion. A watershed management program has been undertaken to prevent soil erosion into Highland Silver Lake.