Areal Studies Aid Protection of Ground-Water Quality in Illinois, Indiana, and Wisconsin

Water-Resources Investigations Report 98-4143
Prepared in cooperation with the U.S. Environmental Protection Agency
By: , and 



In 1991, the U.S. Geological Survey, in cooperation with the U.S. Environmental Protection Agency, initiated studies designed to characterize the ground-water quality and hydrogeology in northern Illinois, and southern and eastern Wisconsin (with a focus on the north-central Illinois cities of Belvidere and Rockford, and the Calumet region of northeastern Illinois and northwestern Indiana). These areas are considered especially susceptible to ground-water contamination because of the high density of industrial and waste-disposal sites and the shallow depth to the unconsolidated sand and gravel aquifers and the fractured, carbonate bedrock aquifers that underlie the areas. The data and conceptual models of ground-water flow and contaminant distribution and movement developed as part of the studies have allowed Federal, State, and local agencies to better manage, protect, and restore the water supplies of the areas.

Water-quality, hydrologic, geologic, and geophysical data collected as part of these areal studies indicate that industrial contaminants are present locally in the aquifers underlying the areas. Most of the contaminants, particularly those at concentrations that exceeded regulatory water-quality levels, were detected in the sand and gravel aquifers near industrial or waste-disposal sites. In water from water-supply wells, the contaminants that were present generally were at concentrations below regulatory levels. The organic compounds detected most frequently at concentrations near or above regulatory levels varied by area. Trichloroethene, tetrachloroethene, and 1,1,1-trichloroethane (volatile chlorinated compounds) were most prevalent in north-central Illinois; benzene (a petroleum-related compound) was most prevalent in the Calumet region. Differences in the type of organic compounds that were detected in each area likely reflect differences in the types of industrial sites that predominate in the areas. Nickel and aluminum were the trace metals detected most frequently at concentrations above regulatory levels in both areas. Contaminants in the shallow sand and gravel aquifers and carbonate aquifers appear to have moved with ground water discharging to local lakes, streams, and wetlands. Ground-water flow and possibly contaminant movement is concentrated in the weathered surface zones and in deeper fractures of the carbonate aquifers underlying both areas.

Suggested Citation

Mills, P.C., Kay, R.T., Brown, T.A., and Yeskis, D.J., Areal studies aid protection of ground-water quality in Illinois, Indiana, and Wisconsin: U.S. Geological Survey Water-Resources Investigations Report 98–4143, 12 p.,

Study Area

Table of Contents

  • Abstract
  • Introduction
  • Water Quality and Hydrogeology of Northern Illinois and Southern and Eastern Wisconsin
  • Water Quality and Hydrogeology of Northeastern Illinois and Northwestern Indiana
  • Summary and Conclusions
  • Related Reports by the U.S. Geological Survey
  • Other Cited References
Publication type Report
Publication Subtype USGS Numbered Series
Title Areal studies aid protection of ground-water quality in Illinois, Indiana, and Wisconsin
Series title Water-Resources Investigations Report
Series number 98-4143
DOI 10.3133/wri984143
Year Published 1999
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Illinois Water Science Center
Description 12 p.
Country United States
State Illinois, Indiana, Wisconsin
Google Analytic Metrics Metrics page
Additional publication details