Water Quality in the Upper Illinois River Basin

Illinois, Indiana, and Wisconsin, 1999–2001


U.S. Geological Survey Circular 1230


By George E. Groschen, Terri L. Arnold, Mitchell A. Harris, David H. Dupré, Faith A. Fitzpatrick, Barbara C. Scudder, William S. Morrow, Jr., Paul J. Terrio, Kelly L. Warner, and Elizabeth A. Murphy


This circular is available as a pdf.


This report contains the major findings of a 1999–2001 assessment of water quality in the upper Illinois River Basin. It is one of a series of reports by the National Water-Quality Assessment (NAWQA) Program that present major findings in 51 major river basins and aquifer systems across the Nation.


In these reports, water quality is discussed in terms of local, State, and regional issues. Conditions in a particular basin or aquifer system are compared to conditions found elsewhere and to selected national benchmarks, such as those for drinking-water quality and the protection of aquatic organisms.


This report is intended for individuals working with water-resource issues in Federal, State, or local agencies, universities, public-interest groups, or in the private sector. The information will be useful in addressing a number of current issues, such as the effects of agricultural and urban land use on water quality, human health, drinking water, source-water protection, hypoxia and excessive growth of algae and plants, pesticide registration, and monitoring and sampling strategies. This report also is for individuals who wish to know more about the quality of streams and ground water in areas near where they live, and how that water quality compares to the quality of water in other areas across the Nation.


The water-quality conditions in the upper Illinois River Basin summarized in this report are discussed in detail in other reports that can be accessed from ( Detailed technical information, data and analyses, collection and analytical methodology, models, graphs, and maps that support the findings presented in this report in addition to reports in this series from other basins can be accessed from the national NAWQA Web site at


National Water-Quality Assessment Program

What kind of water-quality information does the NAWQA Program provide?

Introduction to this Report

Summary of Findings

Stream and River Highlights

Ground-Water Highlights

Introduction to the Upper Illinois River Basin

Major Findings

Urbanization significantly affects streams, biological communities, and ground water

Ammonia and phosphorus are elevated in urban streams and rivers because of wastewater

Domestic and industrial wastewater increased organic contaminants in streams and rivers

Insecticides, such as diazinon, are associated with urban land use

Volatile organic compounds were detected in Salt Creek

Lake sediment reflects urbanization

Biological conditions are adversely affected in urbanizing areas

Organochlorine-pesticide and PAH concentrations were elevated in urban-stream sediment and fish

Contaminants in sediments present risks to aquatic life in and near the
Illinois River

Urban land-use study covers multiple watersheds in the Des Plaines and Fox River Basins

VOCs, pesticides, and nitrate were detected in shallow ground water underlying urban land

Recharge to the ground-water system decreases with urbanization

Extensive agriculture affects streams and ground water

Nitrate and total nitrogen are elevated in agricultural streams

Nitrogen varies significantly in agricultural streams because of geology and land-management practices

Herbicides are common in agricultural streams and in ground water

Water quality has changed since the early 1980s

Ammonia in streams and rivers decreased and nitrate increased

Changes in pesticide use are reflected in streams and rivers

Ten-year-old shallow ground water has higher pesticide concentrations than more recent ground water

Study-Unit Design

Stream Chemistry and Ecology

Ground-Water Chemistry

References Cited


Appendix—Water-Quality Data from the Upper Illinois River Basin in a National Context

Points of Contact and Additional Information


The companion Web site for NAWQA summary reports:


Upper Illinois River Basin contact and Web site:

USGS State Representative

U.S. Geological Survey

Water Resources Discipline

221 N. Broadway Ave.,

Urbana, IL 61801



National NAWQA Program:

Chief, NAWQA Program
U.S. Geological Survey
Water Resources Discipline
12201 Sunrise Valley Drive, M.S. 413
Reston, VA 20192


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U.S. Geological Survey,

Information Services
Box 25286, Denver Federal Center
Denver, CO 80225


For more information about the USGS and its products:

Telephone: 1-888-ASK-USGS
World Wide Web:


The text and graphics are presented here in pdf format (print quality). The full report is 11.4MB.


If you have Adobe® Acrobat® or Adobe® Acrobat® Reader® installed on your computer, you may view and print the PDF version of this report. Acrobat Reader, is a free download it from Adobe Systems, Inc.  Users with disabilities can view information concerning accessibility at


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