|
|
|  |
Iowa Ground-Water-Quality Monitoring Program
PERIOD OF PROJECT: Continuous since 1982
PROJECT CHIEF: G.R. Littin (grlittin@usgs.gov)
STUDY AREA: Statewide
COOPERATING AGENCY: Iowa Department of Natural Resources (Geological Survey Bureau)
NEED FOR STUDY:
Ground-water quality is one of the most critical resource concerns in the
State of Iowa. A ground-water-quality monitoring program is needed to provide
data to aid State and local management and protection agencies to effectively
evaluate the ground-water resources of the State.
OBJECTIVES:
The primary purpose of the ground-water-quality monitoring program is to provide
consistent and representative ground-water-quality data that describe the chemical
quality of ground-water resources in the State. Initially, the primary objective
was to specifically describe the baseline ground-water-quality of the major aquifers
in the State that are stressed by intensive use, contamination, or deteriorating
quality. Since water year 1992, greater emphasis has been placed on determining trends
in ground-water quality and correlating water quality with possible contributing
factors such as location, land use, aquifer, aquifer depth, and precipitation.
PROGRESS:
As of 1992, ninety wells completed in the principal aquifers of the State have been selected
for sampling to determine possible trends in ground-water quality. Wells completed in
surficial and vulnerable bedrock aquifers were sampled on one- or two-year rotational
schedule, respectively. Bedrock wells not vulnerable to contamination were sampled every four
years. All wells were sampled for major ions, nutrients, and common herbicides. Additionally,
shallow wells (less than 300 feet deep) were sampled for selected priority pollutants, and
deep wells (more than 300 feet) were sampled for radionuclides. In 2001, the sampling rotation
was suspended in favor of sampling all 90 wells on an annual basis. In 2002, an additional
60 wells were included in the overall sampling strategy in an effort to better define trends
in the chemical quality of water by aquifer. Beginning with the Mississippian-Cretaceous
aquifers in 2002, a different set of aquifers will be targeted for additional random sampling
each year on a rotating basis. Network data are typically compiled and published in the annual
U.S. Geological Survey Water Resources Data,
Iowa report. In addition, Open-File-Report (OFR)
98-3 "Quality of ground water used in selected municipal water supplies in Iowa, 1982-1996" by
Bryan D. Schaap and S. Mike Linhart was published in 1998. Copies are available for distribution.
The report reviews the water-quality data since the program's inception in 1982 and provides basic
statistics by county, aquifer, and well depth. A CD-ROM of the entire data set accompanies the report.
Sampling results for 1997-2002 water years are published in the USGS Iowa District Annual Report Series.
|
|
|
