2007 Ground Water Summit

Tuesday, May 1, 2007 : 11:40 a.m.

Evaluation of Ground Water Recharge in an Urbanizing, Glacial/Bedrock Aquifer Setting, Illinois by Field, GIS, and Modeling Methods

Colin J. Booth, PhD, PG, Samuel P. Gillet, Alka Singhal and Christopher B. Greer, Northern Illinois University

DeKalb County, west of Chicago’s suburbs, is a mostly rural area facing significant urbanization. The primary water supply is the over-stressed Midwest Bedrock aquifer, but DeKalb city has recently tapped glacial aquifers in the Troy Bedrock Valley (TBV), a major regional pre-glacial drainage feature underlying the western half of the county. The TBV is a buried, steep-sided valley cutting 300 ft deep and 1-2 miles wide through buried dolomite uplands, filled with Pleistocene sediments and having no surface expression. The area is overlain by Wisconsinan drift and comprises minor watersheds of the upper Kishwaukee River. It forms a recharge area for the shallow aquifers, while the TBV is a recharge route to the regional bedrock aquifer, thus aquifer resources are affected on several scales.

Building on recent 3D mapping by the Illinois State Geological Survey, and previous student hydrogeological studies, we are integrating several approaches to determine recharge pathways and quantities and predict impacts of urbanization. Field estimates of recharge were obtained from a 2004-2006 study of a non-urbanized watershed over the TBV, using shallow aquifer water-level responses and a hydrologic budget approach combining field measurements with GIS-based and meteorological data. Secondly, spatially and temporally variable recharge for this and for an adjacent, partially urbanized watershed is delineated using an automated GIS model combining land use, hydrology, and geology with a soil-moisture balance based on calculated ET and runoff. Estimated recharge values vary spatially from 0.2 -13 in/year, including differences between urbanized and rural areas. A MODFLOW model of the shallow (100 ft) system uses this data and GIS-projected urban growth to predict future recharge. Finally, the shallow results are being used in a MODFLOW model of the entire system (glacial aquifers, TBV, and dolomite) to determine recharge to the TBV aquifer and regional sandstone aquifer.

Colin J. Booth, PhD, PG, Northern Illinois University Colin Booth is a professor of hydrogeology at NIU, where he has been since 1984. He obtained his BSc from East Anglia (UK), PhD from Penn State, and PG in Illinois. He has worked in the petroleum and water industries; served on the boards of IAH (US Chapter), IMWA, and other organizations and on the state commission for low-level waste; and is Associate Editor, Mine Water & the Environment. His main research areas are mining hydrogeology, aquifers, and groundwater systems.

Samuel P. Gillet, Northern Illinois University MS student Sam Gillet (field study) obtained his BS from Beloit and has worked for the BLM in Oregon.

Alka Singhal, Northern Illinois University PhD student Alka Singhal (GIS/modeling) obtained her BSc from Garwhal and MSc from Roorkee, worked in GIS and hydrology in India, and has an MS from Ball State.

Christopher B. Greer, Northern Illinois University PhD student Chris Greer (modeling) has a BS from Millsap, MS from Wright State, and previously worked in hydrogeology with CH2M-Hill.


The 2007 Ground Water Summit