The Illinois River drains nearly half of the state. Many of the major streams in Illinois drain into it. The Illinois Waterway, with its system of locks and dams, links Chicago and the Great Lakes to the Mississippi River, and thereby to the Gulf of Mexico. This linkage has a significant transpo1tation and commercial value for the state and the nation. In addition, with its numerous backwater lakes, wetlands, and floodplain forests, the Illinois River valley provides a significant habitat for fisheries, waterfowl, birds, and other animals, making it an important ecological resource. The Illinois River's environment has been subjected to many of the impacts associated with the developments in the watershed, including waste discharges from urban areas, water-level control for navigation, and sediment and chemical inflow from agricultural lands. The water quality of the river was severely degraded for several decades prior to the 1970s, when environmental regulations were enacted to control pollutant discharges. Since then the river water quality has been gradually improving. However, problems associated with erosion and sedimentation still persist and are recognized as the prima1y environmental problem in the Illinois River valley (Illinois State Water Plan Task Force, 1987). Restoration of the Illinois River requires proper understanding of the natural factors and human-induced changes that control hydrology, hydraulics, and water quality over time. To facilitate that process, the Illinois State Water Survey (ISWS) has been assessing trends in hydrology and sediment and nutrient loads in the Illinois River, as well as the resulting sedimentation and water quality issues, for a long time. The results of the latest assessment will be presented.
|Original language||English (US)|
|Title of host publication||The Illinois River : A Watershed Partnership 15th Biennial Governor's Conference on the Managment of the Illinois River System|
|State||Published - 2015|