This is the third and final report on the Kankakee River in Illinois supported by the Conservation 2000 Program of the Illinois Department of Natural Resources. For this project, the Illinois State Water Survey mapped the bank erosion of the main stem of the Kankakee River from the Route 30 bridge in Indiana to the mouth of the Kankakee River with the Illinois River near Wilmington, collected about 100 bed and bank material samples, resurveyed all the previously surveyed river cross sections, surveyed four sand bars, and analyzed all historical and new data.
This research has shown that of 223.6 river bank miles (includes both sides of the river), about 10.4 river bank miles have severe erosion, 39.4 river bank miles have moderate erosion, 70.8 river bank miles have minor erosion, and the remainder are either protected or stabilized or data are not available. The median diameter of the bed materials varied from 0.27 millimeters (mm) to 0.52 mm. The median diameter of bank materials varied from 0.07 mm to 0.41 mm. Analyses of the long-term flows from six gaging stations in Illinois showed an increasing trend in flows through the 1960s with no discernible increase since that time.
Cross-sectional analyses of the river from the Kankakee Dam to the State Line Bridge did show some trends. The river reach from the Kankakee Dam to Aroma Park called Six-Mile Pool has lost 13.4 percent of its capacity due to sediment deposition since 1980. Similarly, Momence Wetland also has lost about 10.2 percent of its capacity since 1980. The section of the river between Aroma Park and Singleton Ditch showed both scour and sediment deposition. In general areas close to Aroma Park exhibited sediment deposition and the middle reach experienced scour. The recurring sand bar at the State Line Bridge area contains about 8,500 cubic yards of additional sediment in 1999 than were measured in 1980. The volumetric measurement of three additional sand bars showed some changes since 1980. The river is accumulating sediments within Six-Mile Pool and Momence Wetland. The middle reach is in semi-equilibrium with some sediment accumulation at several areas. Several management alternatives, both in-channel and watershed-based also are included to assist in the reduction of sedimentation problems of the Kankakee River.Illinois Department of Natural Resources Office of Realty and Environmental Planningpublished or submitted for publicationis peer reviewedOpe