Collection of Hydraulic and Geologic Data to Improve the Quality of the Wisconsin Observation-Well Network

Introduction: The Wisconsin Geological and Natural History Survey (WGNHS) in cooperation with the U.S. Geological Survey (USGS) has maintained a ground-water observation-well network since 1946 (Zaporozec, 1982). The purpose of the network is to determine short-term changes and long-term trends in ground-water levels, and to relate these determinations to changes in storage in the ground-water reservoirs.

Currently, water levels are measured in approximately 170 Wisconsin observation wells (Zaporozec, 1996). Water-level measurements and associated geologic and well construction data are stored in a computer data base, and these data are available to the public upon request. For more information call Bernie Ellefson, USGS, 608/276-3849; or Alex Zaporozec, WGNHS, 608/262-3385. Selected water-level measurements representing the water table are available and updated monthly on the World Wide Web (http://wwwdwimdn.er.usgs.gov/gw/).

Interpretation of water-level measurements from about 30% of network wells is difficult because descriptions of geologic units and estimates of hydraulic conductivity are not available. Identification of the geologic units tapped and estimates of their hydraulic conductivity will increase the value of these measurements. In July 1994, WGNHS in cooperation with the USGS initiated a two-year study to obtain these data. The study was funded cooperatively by the Wisconsin Department of Natural Resources (WDNR), WGNHS and USGS. Funding from WDNR came from the Groundwater Account of the Environmental Fund (DNR Project No. 118).