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Why do we study ground water?
Ground water is an important source of water
supply in Illinois. About 2.5 million people in Illinois are
supplied from ground-water resources. Total ground-water withdrawals
in the State was approximately 953 million gallons per day in
1995. Ground-water withdrawals account for about 21 percent of the
total water withdrawn for public-water supplies in Illinois. Tens
of thousands of persons in the State rely on ground water from
residential wells as their sole source of water. The largest
amount of ground-water withdrawals is in the northern one-third of
the State where large supplies of potable water are available in
aquifers that range in depth from about 10 feet to about 1,500
feet.
Ground-water quality is a major concern in
Illinois. Water-quality degradation or contamination results from
point and nonpoint sources throughout the State. In many
industrialized parts of the State, including the metropolitan
areas of Chicago, Rockford, and St. Louis, ground water in
aquifers in the glacial deposits and bedrock has been degraded by
improperly contained or disposed chemicals. In many agricultural
areas, the quality of ground water in the underlying shallow
aquifers has been degraded by the routine application of
agricultural chemicals. Surface-water quality has been degraded in
some areas because of the influx of contaminated ground water.
What do we do?
The U.S. Geological Survey (USGS), Illinois Water
Science Center, performs various ground-water activities primarily
within the State of Illinois. The USGS has conducted numerous
hydrologic studies in Illinois since 1955 concerned with
ground-water quantity and quality. Many of these studies are done
in cooperation with local, State, and Federal agencies and
organizations. These studies include:
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studying regional patterns and trends in ground-water
quality based on a network of 117 wells in shallow and deep
glacial aquifers in central Illinois, lower
Illinois River Basin, as part of the National
Water-Quality Assessment Program.
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studying long-term trends in ground-water
quality in the upper
Illinois River Basin as part of the USGS National
Water-Quality Assessment Program.
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cooperative
studies with the U.S. Environmental Protection Agency,
Region 5, concerning ground-water quantity and quality at
hazardous-waste sites located in cities and towns such as
Rockford, Byron, and Belvidere, in regional areas such as southeast
Chicago/northwestern Indiana and in the Galena-Platteville
aquifer underlying much of northern Illinois and southern
Wisconsin.
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monitoring a network of up to 13 wells to
observe water-level fluctuations (an indicator of changes in
ground-water storage resulting from climatic variability and
pumpage) until 1998.
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studying radium
in ground water from aquifers used for public supply in
northern Illinois.
Various State of Illinois agencies are responsible
for ground-water assessment, management, and protection programs
in Illinois. Some of these agencies include the Illinois
Department of Natural Resources*, which includes the State
Geological* and State Water
Surveys* and the Office
of Water Resources*; the Illinois
Environmental Protection Agency*; the Illinois
Department of Public Health*; and the Illinois
Pollution Control Board*.
*External Web site that is not associated with the U.S.
Geological Survey.
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