APPLICATION OF A 3-D GEOLOGIC MAPPING AND VISUALIZATION PROGRAM TO ADVANCE WATER RESOURCE MANAGEMENT IN MCHENRY COUNTY, ILLINOIS

The population of McHenry County, Illinois is one of the most rapidly growing in the state. It is projected that portions of the county will experience water shortages as soon as 2020. The County is solely dependent on groundwater for its drinking water supplies with no other options available. To help County officials better protect and manage their groundwater resources, the Illinois State Geological Survey (ISGS) and the County initiated a multi-year project focused on development of a series of planning support maps derived from a comprehensive 3-D geologic map.

The first year of the study involved the acquisition of both archival and new data, including water well and engineering drillers logs, 2-D seismic profiles, electrical resistivity, ISGS drilling and sampling, and observation well installation. The second year of the project includes data analysis and interpretation, the creation of an integrated set of geologic surface maps and the development of a suite of custom derivative maps.

To facilitate the interpretation and mapping, an integrated 3-D visualization environment has been developed using custom programs written at the ISGS for use with ArcScene software. These software applications have allowed ISGS staff to visualize and interact with the various multi-resolution geologic data in 3D. Together with innovations in data management, these tools have provided us advanced capabilities in the identification and mapping of the various stratigraphic, lithologic, and facies relationships. These tools also have been instrumental in providing efficiencies in mapping the distribution of regional and local aquifer systems and in characterizing much of the variability within them, providing timely support for water-resource decision makers.