Evaluation of Potential Removal and Beneficial Use of Illinois River Sediment

The Illinois Department of Natural Resources is investigating techniques for removing sediment and using it beneficially. Numerous sediment cores, including ten extending two meters, were analyzed for a variety of metals and chemicals as well as agricultural nutrients. Plant germination and growth tests comparing fresh and weathered sediment to Illinois topsoil were conducted in a greenhouse. A hydrodynamic model of a portion of the river was developed to assist in predicting the effects of sediment removal and placement. A number of options to remove sediment at near insitu moisture content are under consideration including high solids pumps, excavators, clamshells and conveyors. This would minimize turbidity, resuspension and dewatering while maximizing options for sediment transport and placement. Researchers are looking at sites where dredged material was placed in the past to determine the qualities of soil formed by fine-grained sediment similar to that in the Illinois River. It is hoped that sediment will prove useful as a landscaping soil, soil amendment, brownfield cover and for strip mine reclamation. Additionally sediment may be used to create islands and floodplain habitat that is similar in elevation and geometry to that which existed prior to the major hydrologic changes that occurred beginning in 1900.