Population growth may be an economic boon for communities, but the subsequent increased water demand could threaten the amount and quality of public water supplies available within the next few decades, according to Scott Meyer, hydrogeologist at the Illinois State Water Survey (ISWS), a division of the Institute of Natural Resource Sustainability at the University of Illinois.

"Concerned groups at the community and county level are beginning to realize that water supply planning is a priority issue," Meyer said. "It is important to know which local water resources will be affected by rising demand, potential drought, and climate change and the degree to which these resources will be affected."

Kane County in northeast Illinois has taken progressive steps to predict future water supply changes in order to avoid water shortages. The population in Kane County is projected to surge 70 percent from 2000 to the year 2030, undoubtedly boosting water demand. The county must consider its options to ensure continued availability of clean water supplies.

The Kane County Development Department commissioned the ISWS (and sister survey Illinois State Geological Survey) to determine the status of current and future groundwater resources in the county to the year 2050. ISWS researchers developed regional- and local-scale groundwater flow models, which are sets of interrelated mathematical equations that represent water flow in aquifers and streams. Computer programs are used to solve the equations, thereby determining the effects of groundwater usage and stressors, such as drought.

"The models provide a rational basis for developing policy and management strategies pertaining to water-resources development in the area," Meyer said.

Significant groundwater pumping causes water levels inside wells to decline, leading to higher costs and possible well failures, less groundwater flowing to local streams, and lower water levels in lakes and wetlands. Pumping can even cause poor quality groundwater, Meyer said.

Using computer models and other data and analyses, Meyer and his colleagues at ISWS predicted that groundwater pumping in Kane County may increase from 37 million gallons per day (mgd) in 2000 to as much as 71 mgd by 2050 to meet increased demand.

Model simulations also showed:

• Groundwater withdrawals from deep wells will potentially cause water supply interruptions and increasing concentrations of radium, barium, arsenic, and salinity in the water supply. These problems will be greatest in the Aurora area.

• In shallow wells, the researchers identified two large areas of significant drawdown, or declines in water levels. The largest area included parts of northeastern Kane County and Southeastern McHenry County, and the second area developed in response to pumping by the City of West Chicago. A third area will likely develop around public-supply wells operated at Batavia and Geneva.

• Water in local streams may decline, potentially harming fish populations and plants. During periods of low precipitation, Mill Creek, for example, may dry up completely by 2050.

Study results are available on the ISWS Web site at http://www.isws.illinois.edu/docs/pubs/ISWSCR2009-07/

"Although the data and projections are specific to Kane County, the studies can be used as a framework for water supply planning initiatives in other Illinois counties," Meyer said.

Wise water management is based on sound technical information and planning, taking into account such matters as climate variations and change, renewable yields of surface waters and aquifers, and water conservation.

Communities or counties interested in assessing their water resources will want to start by determining present and future water needs and by gathering data on existing water sources, including water levels in wells, stream levels, and interactions between groundwater and surface water.

The Illinois State Water Survey assists water supply planners from the community to the state level in assessing current water supply conditions and evaluating the availability, quality, and use of local surface and groundwater resources. For more information on water supply planning, contact the ISWS Center for Groundwater Science, (217) 333-4300.

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Source: Scott Meyer, 217-333-5382; smeyer@illinois.edu

Editor: Lisa Sheppard, 217-244-7270; sheppard@illinois.edu

Illinois State Water Survey: http://www.isws.illinois.edu/

8/25/09