Regions
Eleven planning regions have been defined throughout the state, and ISWS has done work for the East Central Illinois Basin, Kankakee Subregion, Kaskaskia River Basin, Middle Illinois, Northeastern Illinois, Rock River, and American Bottoms regions. Future water supply planning will be conducted in the remaining regions.
Region Map
Rock River
The Rock River region includes Jo Daviess, Stephenson, Winnebago, Boone, Carroll, Ogle, Whiteside, Lee, Rock Island, Henry, and Bureau counties.
Northeastern Illinois
The Northeastern Illinois region comprises the greater Chicago region and includes McHenry, Lake, DeKalb, Kane, DuPage, Kendall, Will, Grundy, and Cook counties.
Spoon/Lamoine River
The study of this region has not yet been implemented and will be included in a future phase of the project.
Middle Illinois
The Middle Illinois region includes LaSalle, Livingston, Marshall, Peoria, Putnam, Stark, and Woodford counties.
Kankakee Watershed
The Kankakee Watershed subregion includes Kankakee, Iroquois, and Ford counties.
East Central Illinois
The East Central Illinois region includes Cass, Champaign, Dewitt, Ford, Iroquois, Logan, Macon, Mason, McLean, Menard, Piatt, Sangamon, Tazewell, Vermilion, and Woodford counties.
Lower Illinois River
The Lower Illinois River region includes Calhoun, Greene, Jersey, Morgan, Macoupin, Pike, and Scott counties.
Kaskaskia River
The Kaskaskia River region includes Bond, Christian, Clay, Clinton, Coles, Cumberland, Douglas, Effingham, Fayette, Jasper, Jefferson, Macoupin, Madison, Marion, Monroe, Montgomery, Moultrie, Perry, Randolph, Richland, St. Clair, Shelby, Washington, and Wayne counties.
Wabash/Ohio River
The study of this region has not yet been implemented and will be included in a future phase of the project.
American Bottoms
The American Bottoms region includes portions of St. Clair, Madison, and Monroe counties adjacent to the Mississippi River.
Big Muddy
The Big Muddy region includes Jefferson, Franklin, Williamson, Perry, and Jackson counties.
Counties within Regions
Some counties appear in more than one water supply planning region, and some regions are still being planned and do not list counties.
The East Central Illinois region encompasses Cass, Champaign, DeWitt, Ford, Iroquois, Logan, Macon, Mason, McLean, Menard, Piatt, Sangamon, Tazewell, Vermilion, and Woodford counties. The Kankakee Watershed region contains Kankakee, Iroquois, and Ford counties. The Northeastern Illinois region comprises greater Chicago, including McHenry, Lake, DeKalb, Kane, DuPage, Kendall, Will, Grundy, and Cook counties. The Middle Illinois region consists of LaSalle, Livingston, Marshall, Peoria, Putnam, Stark, and Woodford counties. The Kaskaskia River includes Bond, Christian, Clay, Clinton, Coles, Cumberland, Douglas, Effingham, Fayette, Jasper, Jefferson, Macoupin, Madison, Marion, Monroe, Montgomery, Moultrie, Perry, Randolph, Richland, St. Clair, Shelby, Washington, and Wayne counties. The Rock River region covers Jo Daviess, Stephenson, Winnebago, Boone, Carroll, Ogle, Whiteside, Lee, Rock Island, Henry, and Bureau counties.
A key component of this water supply planning work is groundwater modeling. The Illinois Groundwater Flow Modeling Framework can assess a wide range of groundwater issues at local, regional, and interstate scales.
ISWS has created multiple interactive maps to help people understand water use and issues in Illinois. One of these interactive maps identifies the source of water for each of the more than 1,300 communities in Illinois, used for municipal, industrial, and residential purposes.