Groundwater Studies for Water-Supply Planning in McHenry County, Illinois
Groundwater is an especially important resource to McHenry County, as underlying aquifers provide 100 percent of the county's water supply. That dependence is likely to grow as the county's population swells from 304,000 in 2005 to an estimated 589,000 in 2050, a 94 percent increase. Low-resolution groundwater flow modeling of the Fox River watershed, conducted by the ISWS as required by Governor's Executive Order 2006-01, suggests that drawdown currently exceeds 5 feet in shallow aquifers in much of central and southeastern McHenry County, and that these areas will expand significantly by 2050, possibly affecting groundwater availability (Meyer et al., in preparation). The modeling also suggests that reductions in groundwater discharge to streams currently exceeds 10 percent in some southeastern McHenry County streams, and that the number of streams affected to this degree will increase greatly by 2050, possibly affecting stream health. Land cover changes may also affect groundwater quality, as ISWS studies have demonstrated elsewhere in northeastern Illinois (Kelly and Wilson, 2008). This project, conducted cooperatively with the ISGS and USGS, will develop a high resolution groundwater flow model of the shallow aquifers of McHenry County to provide more detailed and accurate estimates of the effects of future development on the groundwater hydrology. The ISWS will also collect water level measurements from selected available existing wells in McHenry County to update the 1994 measurement summarized in Meyer (1998). McHenry County's shallow observation well network will be sampled to assess current groundwater quality.
Selected Related Publications
Kelly, W. R., and S. D. Wilson., 2008. An Evaluation of Temporal Changes in Shallow Groundwater Quality in Northeastern Illinois Using Historical Data. Illinois State Water Survey Scientific Report 2008-01.
Meyer, S. C., H. A. Wehrmann, H. V. Knapp, Y-F. Lin, F. E. Glatfelter, D. Winstanley, J. R. Angel, J. F. Thomason, and D. Injerd., 2009b. Opportunities and Challenges of Meeting Water Demand in Northeastern Illinois. Illinois State Water Survey Contract Report (in preparation).