Kendall County is entirely dependent on groundwater to supply its communities, industries, and rural residents. Although the Fox River passes through the county and could potentially be used as a source of water supply, it is currently not being used. Therefore, a sustainable Kendall County must be based, in large part, on sound planning and management decisions regarding groundwater availability and use within the county.
In 2003, an assessment of the county’s surface water and groundwater resources was initiated by the U.S. Geological Survey (USGS), in cooperation with the Kendall County Soil and Water Conservation District and Kendall County municipalities. The USGS presented a compilation of previous investigations of the region’s water resources by numerous county, state, and federal research and regulatory agencies supplemented with limited new data collected from three new supply wells drilled for the City of Yorkville (Kay et al., 2005). An awareness of the link between sound groundwater management and a sustainable future prompted the county to approach the Illinois State Water Survey (ISWS) and Illinois State Geological Survey (ISGS) to provide additional technical information and support for the management and protection of their groundwater resources.
In response, the surveys proposed a series of investigations designed to provide information relevant to the long-term availability and sensitivity to contamination of groundwater resources in Kendall County. While these investigations will not provide answers to site-specific wellfield management or groundwater remediation questions, they do provide a county-wide evaluation and scientifically-based summary of what is known based on the latest available and newly collected information. The groundwater model developed for Kendall County can be used in the future to address alternative pumping scenarios and determine the possible impacts of future groundwater development at additional locations not addressed in this report.
This report summarizes results from studies performed by the ISWS and a separate report provides the details of ISGS investigations (Keefer et al., 2013). This report includes a section on observed groundwater levels (observations listed in Appendix A) and groundwater quality (with chemical results in Appendix B). The fourth chapter presents a description of the groundwater flow model of the aquifers supplying Kendall County and the model calibration results. The fifth chapter presents the flow model results. The last chapter provides a summary of the results of all the investigations. Emphasis is placed on the results of simulations of groundwater withdrawals from aquifers beneath Kendall County and, by default, the northeastern Illinois region. The sandstone aquifers (the Ancell and Ironton-Galesville sandstones) underlie all of northeastern Illinois; as such, large withdrawals from outside Kendall County have major impacts within Kendall County. Kendall County’s principal Quaternary sand and gravel aquifers lie essentially only within the Fox River basin; significant sand and gravel deposits do not exist elsewhere in Kendall County.