Watersheds of Illinois - 1996

27. Mississippi South Central River Watershed

The Mississippi South Central River Watershed in southwestern Illinois includes the Mississippi River and its tributaries between the lower Illinois River Watershed and the mouth of the Kaskaskia River. This area exhibits a variety of land types from rolling hills at the edge of the Southern Till Plain, to the Mississippi River floodplain, and the bluffs in between. The watershed covers 746,111 acres in Calhoun, Jersey, Macoupin, Madison, St. Clair, Monroe, and Randolph counties. The largest cities in the watershed are Belleville (42,806), Edwardsville (34,582), Alton (33,064), Granite City (32,769), Collinsville (22,424),and Godfrey (16,085). Major streams which comprise the watershed include the Mississippi River, Maeystown Creek, Fountain Creek, Canal One, Cahokia Canal, Cahokia Creek, Wood River, and Piasa Creek. A total of 747 stream miles were assessed within the watershed. Overall resource quality is "good" on 168 stream miles (23%), "fair" on 544 stream miles (72%), and "poor" on 35 stream miles (5%). The primary causes of water quality problems are siltation and suspended solids attributed to agricultural runoff, hydrologic/habitat modifications, and point sources. A total of 16 lakes covering 3,176 acres were also assessed in the watershed. Overall resource quality is "good" on 228 acres (7%) and "fair" on 2,948 acres (92%). The primary causes of water quality problems are siltation, suspended solids, and organic enrichment (low dissolved oxygen) attributed to agriculture, urban runoff, and contaminated sediments (sediment and/or phosphorus attached to sediment particles).

Mississippi River

The Mississippi River (J) flows south from Brussels, Ill., to Reily Lake, Ill., at the confluence of the Kaskaskia River. A total of 206 stream miles of the Mississippi River were assessed in the Mississippi South Central River Watershed. Of the total, 183 stream miles were rated as "fair," and the overall resource quality of 23 stream miles was rated as "poor." Causes of pollution include siltation, habitat alterations, and suspended solids attributed to agriculture, hydrologic/habitat modifications, and point sources.

Cahokia Canal

Of the 14 stream miles assessed on the Cahokia Canal (JN), two stream miles were rated as "fair" and 12 stream miles were rated as "poor" in terms of the overall resource quality. Causes of pollution include metals, ammonia, nutrients, siltation, and suspended solids attributed to agriculture, urban runoff, construction, hydrologic/habitat modifications, and point sources.

Cahokia Creek

Cahokia Creek (JQ) originates in Macoupin County and flows southwest to Edwardsville where it has been diverted west to the Mississippi River. A total of 50 stream miles were assessed on Cahokia Creek. Of the total, 14 stream miles were rated as "good," and the overall resource quality of 36 stream miles was rated as "fair." Causes of pollution include metals, habitat alterations, and suspended solids attributed to agricultural runoff, hydrologic/habitat modifications, and resource extraction.

Frank Holten State Park Lakes

Frank Holten Lakes #1, #2, and #3 (RJK, RJL, RJM) are located near East St. Louis in St. Clair County. The lakes are inter-connecting lagoons, dammed during the 1930s. The surface area of the lakes are 97, 40, and 80 acres, respectively. The overall resource quality of the lakes is "fair." Causes of pollution to the lakes include nutrients, siltation, suspended solids, and organic enrichment (low dissolved oxygen). Sources include urban runoff and runoff from surrounding parkland areas. Since the mid-1980s, these lakes have undergone extensive monitoring and rehabilitation to improve the quality of this urban recreational resource.

Horseshoe Lake

Horseshoe Lake (RJC), Madison County, is managed by the Illinois Department of Natural Resources. The lake is a natural backwater/oxbow lake of the Mississippi River. It has a surface area of 2,107 acres and has a 20,534 acre watershed. The overall resource quality of the lake is considered "fair." Causes of pollution to the lake include siltation, suspended solids, and organic enrichment (low dissolved oxygen). Sources of pollution include agriculture and industrial point sources.

Holiday Shores Lake

Holiday Shores Lake (RJN), Madison County, is managed by the Holishore Lake Association. The lake is 430 acres, and its watershed is 3,950 acres. The overall resource quality of the lake is considered "fair." Causes of pollution include siltation, suspended solids, noxious aquatic plants, and organic enrichment (low dissolved oxygen). Sources of pollution include agriculture, construction, and urban runoff. The Association has recently installed a sewer system to replace septic systems, many of which were failing.