Both reports and additional information about water supplies in Illinois are available on the ISWS Web site (http://www.sws.uiuc.edu/hilites.asp). The Illinois Report is also available on the web site of the Department of Geography and Environmental Resources, Southern Illinois University (SIU) at Carbondale (http://info.geography.siu.edu/geography_info/research/documents/ISWS_IL_Water_Use_Projections.pdf). “The ISWS is a Division of the Illinois Department of Natural Resources and an affiliated agency of the University of Illinois at Urbana/Champaign,” says Winstanley.

According to Professor Ben Dziegielewski, Department of Geography and Environmental Resources, SIU at Carbondale, lead author of both reports, “County-Level Forecast of Water Use in Illinois: 2005–2025 includes estimates of future water use in Illinois counties based on the best available data and forecasting methods. The result is a set of water demand forecasts for seven water-use sectors in Illinois: thermoelectric, public supplies, self-supplied commercial and industrial usage, irrigation, mining, and livestock.”

“Water use is expected to grow faster than the state’s population, which is projected to increase by 1.5 million over the next 20 years. Projected water use increases from 1,302 gallons per capita per day (gpcd) in 2000 to 1,487 gpcd in 2025, primarily due to projected increases in the thermoelectric sector,” says Dziegielewski.

“By 2025, almost 17 billion gallons of water per day will be needed for generating electricity in Illinois. This will be about 8 times greater than the amount of water diverted from Lake Michigan. Some 97% of the water needed to produce energy is recycled, but up to 3% is consumed. This means that by 2025 up to 500 million gallons of water per day (mgd) will be consumed to generate electricity for Illinois, the Midwest, and the nation,” says Winstanley.

“Total water use is projected to increase in 89 of Illinois’ 102 counties. Public water supplies are often of most concern to planning agencies, and that usage is projected to increase from 164 gallons per person per day in 2000 to 181 gpd in 2025. Some of those projections could be reduced by implementing water conservation programs and improving efficiency of water use,” says Winstanley.

The thirsty spot in the state is the Chicago metropolitan area. “Public supply water use is projected to increase by an average of about 30% in Cook, DuPage, Will, Lake, and Kane Counties, requiring an additional 450 mgd,” says Winstanley.

“These forecasts should provide a benchmark for use in regional water-supply studies. Regional or local planners could allocate county-level projections into smaller areas (townships and cities) by prorating county totals based on population, employment, or other demand drives in each sector. These forecasting methods also could be used to project water use based on locally available data sources,” Dziegielewski says.

“Planners also need to be prepared for periods of drought, when water supply diminishes and water demand increases,” adds Winstanley.

“Project sponsors for the Illinois study were the ISWS and SIU Carbondale Department of Geography and Environmental Resources, with funding from the Illinois Board of Higher Education. Sponsors for the regional report were the U.S. Environmental Protection Agency’s Midwest Technology Assistance Center, housed at the ISWS, and SIU,” says Winstanley.

Countywide Projections of Community Water Supply Needs in the Midwest analyzes county-level, public-supply water use in Illinois, Indiana, Michigan Minnesota, Ohio, and Wisconsin (http://mtac.sws.uiuc.edu/). “The report gives useful insights about the relationship between water use and factors most likely to predict or explain water use. It provides a perspective on the challenges facing water system managers and regional officials in planning necessary to meet future water system infrastructure needs in the region. It also reviews water-use projections and related findings of the study, and recommends actions that may improve water-use forecasting and infrastructure planning for drinking water systems,” says Dziegielewski.