Sediment causes economic and environmental concerns in the Illinois River valley, Illinois State Water Survey

ISWS Press Release

For Immediate Release March 27, 2017
Sediment causes economic and environmental concerns in the Illinois River valley
Laura Keefer - (217) 333-3468,
Lisa Sheppard - (217) 244-7270,

CHAMPAIGN, Ill. - Although water quality in the Illinois River has improved since regulations were enacted to clean up pollution, an ongoing–yet pressing–issue is too much sediment delivered into the Illinois River valley and its connected backwater lakes.

Illinois River

Researchers at the Prairie Research Institute's Illinois State Water Survey (ISWS) have computed a sediment budget over 35 years to determine the amount of sediment coming into the river valley and the amount going out to the Mississippi River. Research shows that an average 12.9 million tons of sediment was delivered annually to the Illinois River valley in 1981 to 2015, and only 5.2 million tons has been removed from the area, according to Laura Keefer, fluvial geomorphologist at ISWS.

Therefore, on average, an estimated 7.8 million tons of sediment from tributary streams, or 60 percent, was deposited annually. The total deposition of sediment may be higher as a result of erosion from river banks and bluffs along the main stem of the Illinois River.

The intensity of water flowing across the land and into rivers and lakes is an especially important factor in sediment deposition, Keefer said.

“Fast flowing water is hungry water; it has teeth,” said Keefer, describing the way that water flows from the land and stream channels, eroding sediment and depositing it into river valleys and bottoms.

Researchers are especially concerned about the main river channel and backwater lakes of the river. Sediment deposition has already filled in several backwater lakes and nearly filled others, with economic ramifications for river towns and habitat degradation. This string of lakes plays a major role in the Mississippi flyway, where migrating waterfowl stop to rest on their journeys. Sediment also disrupts bird and animal habitats and fisheries.

Another significant issue is the economic impact of barge traffic along the Illinois River. The U.S. Army Corps of Engineers must have the resources to remove sediment to keep navigation channels clear for barge freight and boating.

The study report, The Sediment Budget of the Illinois River: 1981-2015, is available on the ISWS website at


About the Prairie Research Institute: The Prairie Research Institute (PRI) at the University of Illinois at Urbana-Champaign provides objective expertise, data, and applied research to aid decision making and provide solutions for government, industry, and the people of Illinois. PRI is the home of the state's five scientific surveys: the Illinois Natural History Survey, Illinois State Archaeological Survey, Illinois State Geological Survey, Illinois State Water Survey, and Illinois Sustainable Technology Center.

Media contact: Laura Keefer, 217-333-3468,; Tricia Barker, Associate Director for Strategic Communications, 217-300-2327,

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