Evaluation of Geology and Hydraulic Performance of
              Wisconsin Ground-water Monitoring Wells

            James M. Rauman, Bernard R. Ellefson, and Alexander Zaporozee
                                         April 1999


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, 1996). The purpose of the network is to relate short-term changes and long-term trends in
ground-water levels to changes in storage of ground-water aquifers and provide data needed for ground-
water research and effective management of ground water resources in Wisconsin.

Currently, water levels are measured in approximately 140 observation wells. Water-level measurements
along with associated geologic and well construction data are stored in a computer database. These data
are available to the public upon request. Representing regional areas of Wisconsin, 16 wells have been
selected to have their water levels updated monthly on the World Wide Web
(http://wwwdwimdn.er.usgs.gov/gw/). All of the wells in the ground-water network are updated at this
web address annually. For more information call Bernie Ellefson, USGS, 608/821-3849; or Alex
Zaporozec, WGNHS, 608/262-3385.

Interpretation of water-level measurements from approximately 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 (Dunning and others, 1996). Accessible wells (wells that could be tested or
logged) were identified from the ground-water observation-well network. The study obtained
geophysical data and estimates of hydraulic conductivity on 37 observation wells based on their regional
representation of the state. These data suggested that 30% of the selected wells had very slow to no
response to the displacement/recovery tests and may have a poor connection with the aquifer. Results of
this study warranted investigation of the remaining 16 accessible wells in the network. In July of 1996
the Wisconsin Department of Natural Resources (WDNR), WGNHS and USGS cooperatively funded a
study to obtain data from the remaining accessible wells. Funding from the WDNR came from the
ground water account of the Environmental Fund (DNR Project No 135).

                                      Selection of Wells

Wells selected for this study included the remaining observation wells identified as accessible for testing
during the previous project (1994-1996) and some additional network wells identified later. From the 19
wells included in the project proposal, three wells (BR-46, ML-148 and ON-22) could not be tested
because they were found to be sealed. The 16 tested wells are listed in Table 1. One well, WS-8, which

was tested in the previous project, was re-tested as part of the quality control of results. The tested wells
range in depth from 13 to more than 350 feet. Most of them are in the sand and gravel aquifer (11
wells); one well is open to the Silurian dolomite aquifer, one to the Galena-Platteville dolomite and three
to the sandstone aquifer (Table 1).