SUMMARY OF REPORT ON GROUNDWATER FLOW IN THE PRAIRIE DU
CHIEN AQUIFER, SOUTHEASTERN MINNESOTA
5/10/02
Anthony C. Runkel and Robert G. Tipping,
Minnesota Geological Survey Minnesota Geological Survey (MGS) Scientists
Robert Tipping and Anthony Runkel recently completed a two-year hydrogeologic
study of the Prairie du Chien Group and underlying Jordan Sandstone. The Legislative
Commission on Minnesota Resources funded this project, the goal of which was
to characterize groundwater flow in the Prairie du Chien Group, and underlying
Jordan Sandstone of southeastern Minnesota. This page summarizes the project
results, for an expanded report refer to the Preliminary
Report on Groundwater Flow in the Prairie du Chien aquifer, Southeastern Minnesota.
The results will be described in greater detail in the final report which is
being prepared as a Minnesota Geological Survey Report of Investigations.
The results of this project have the following practical applications:
- 1) delineating hydrogeologic settings and wellhead vulnerability
of municipal water supplies as mandated by State Wellhead Protection Rules
written by the Minnesota Department of Health (MDH;.
- 2) improvements to continuing bedrock hydrogeologic studies by the
Department of Natural Resources (DNR), United States Geological Survey (USGS),
and the MGS that suffer from inadequate understanding of fracture flow. Such
studies include pollution sensitivity mapping and delineation of recharge
areas of the most widely used aquifer system in southeastern Minnesota;
- 3) provide accurate hydraulic parameters of fractured aquifers for
use in computerized groundwater models such as those currently being used
at a city-scale (e.g. the City of Rochester, by the USGS), and at a regional-scale
(e.g. Twin Cities Metro area, by the MPCA);
- 4) providing information and data for effective regulatory guidelines
for the construction and abandonment of water wells; and
- 5) To provide a framework of groundwater flow characteristics for
used in site-specific investigations such as sewage treatment lagoons, feedlot
sites, leaking tanks, spills, and hazardous waste disposal sites.
Specific results include:
- Field investigations of outcrops and existing boreholes in southeastern
Minnesota. Cavities are preferentially developed in the middle to upper
part of the Prairie du Chien, whereas its lower part contains relatively few
cavities (e.g. Figure 1).
- Drilling of boreholes for rigorous scientific testing.Three scientific
boreholes drilled in Rice (Figure 2), Washington,
and Olmsted counties allowed us to collect detailed hydraulic measurements
of the Prairie du Chien Aquifer. Natural gamma, electric, caliper, EM flowmeter,
and video logs were collected at all three boreholes.
- Interpretation and synthesis of data, and compilation of maps, cross-sections,
and reports. Preliminary Report on Groundwater
Flow in the Prairie du Chien aquifer, Southeastern Minnesota
