Geological Research at the IGS
  

Evaluation of groundwater age and chemistry relations in aquifer systems in Lake, Porter, and La Porte Counties

Status Start Date End Date Locations
completed Lake, LaPorte, Porter
Director: Nancy Hasenmueller
Other Researchers: Tracy Branam Dave A. Cohen, U.S. Geological Survey, retired
Issue: This project to evaluate the groundwater and chemistry relations in aquifer systems in Lake, Porter, and La Porte Counties is, in part, an extension of several earlier water-quality studies in northwestern Indiana. These projects included baseline surveys of the distribution of O18, deuterium and tritium, and major and trace elements in unconsolidated and bedrock aquifers. The projects also examined the relation of the water chemistry to the types/composition of the geologic materials incorporated in the glacial aquifers. Knowledge of relative ages of groundwater can be basic to understanding groundwater flow and sensitivity. For instance, water derived from cold-climate-precipitation (glacial age more than 14,000 years before present) may help to define parts of the lake-plain aquifer in which the water is impeded by the position in the flow system. These areas of the aquifer may be less sensitive to contamination from nearby surface sources. At the opposite extreme, tritium-enriched water indicates a very recent age.
Objective: This project defined groundwater flow systems and their chemistry within Lake, Porter, and La Porte Counties.
Approach: Groundwater samples were collected from monitoring wells and drinking water wells in Lake, La Porte, and Porter Counties. The concentrations of major and trace elements and isotopes in the groundwater samples were determined. Water chemistry data was analyzed, the factor analyses were run, and the factor analyses data for selected elements and isotopes were plotted on maps.
Products: The report and data set from this study is available on CD-ROM. See N.R. Hasenmueller, T. Branam, and N. Bleuer, J. Olejnik, D. Cohen, and M. O'Neal, 2001, Evaluation of Ground-Water Age and Chemistry Relations in Aquifer Systems in Lake, Porter, and LaPorte Counties of Indiana, Indiana Geological Survey Open-File Study 01-21. The publication includes the hydrogeologic settings, isotopic analyses of the water samples, relation of water chemistry to hydrogeologic settings, and aquifer sensitivity in a geographic information system (GIS) format.
Benefits: The knowledge gained relating to ambient conditions will allow regulators to determine more easily the source of groundwater contaminants in this area. The information will also allow domestic and public water supply users to take the necessary steps to assure that their drinking water does not present an unnecessary health hazard.
Publications:

Evaluation of Ground-Water Age and Chemistry Relations in Aquifer Systems in Lake, Porter, and LaPorte Counties of Indiana
Hasenmueller, N.R., Branam, T.D., Bleuer, N.K., Olejnik, J., O’Neal, M.A., and Cohen, D.A., 2001, Evaluation of ground-water age and chemistry relations in aquifer systems in Lake, Porter, and La Porte Counties of Indiana: Indiana Geological Survey Open-File Study 01-21, CD-ROM.


 
 
 
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