104B Base Grants – Characterizing Aquifer Geometries

Groundwater resource assessments in glaciated regions require buried bedrock elevation data to provide information related to aquifer geometry and to determine water-resource availability. In northern Indiana such assessments are needed because expanded irrigation is increasing groundwater withdrawals in the region. Furthermore, naturally occurring contaminants have become an emerging issue, based on recent groundwater sampling data. An improved understanding of bedrock valley morphology is also warranted by these concerns because rockwater interactions at the sediment/bedrock interface often control the geochemical characteristics of groundwater, highlighting the need to better constrain the hydrogeologic conditions at the base of glacial aquifers. At this juncture, there is limited data control for interpolating bedrock topography in northern Indiana. The work proposed herein employs newly developed passive seismic geophysical techniques to establish additional bedrock elevation data and support higher-resolution maps of buried valleys that lie below the St. Joseph Aquifer System in St. Joseph and Elkhart Counties. The data will be collected by an Indiana University student intern who will use geostatistical techniques to interpolate a high-resolution bedrock elevation model for the area and create a digital database of field data and derivative products. The research will improve our hydrogeologic understanding of the constraints on the St. Joseph Aquifer System and develop methods that can be used in statewide water-resource assessments.