HIGH-RESOLUTION SHALLOW AQUIFER MODELING IN MCHENRY COUNTY ILLINOIS

A detailed surficial geologic map and a high resolution profile of an area in Woodstock IL were created in cooperation with the Illinois State Geological Survey. This map and profile were created to clarify the highly variable nature of glacial sediments, to create a three dimensional model of a shallow aquifer, and to help the city of Woodstock better understand their groundwater resources. A detailed surficial geologic map of the Woodstock quadrangle was created in Arc GIS 10 from over 1000 borehole records and soils data. This map aids in the understanding of a glacial history in creating a profile. A high resolution profile using electrical earth resistivity, shallow seismic reflection, down-hole electrical resistivity and natural gamma ray logs, and core descriptions were combined using Petrel 2011. Petrel is a software package traditionally utilized by the petroleum industry. Petrel was used because of its ability to render, interpret, and infer boundaries in three dimensions. Results show a high variability in sediment across a short distance and that geophysical data displayed in 3-D in Petrel can help create a high detailed shallow aquifer model.