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samples collected from 75 shallow aquifer wells and a review of recent historical data in the
ISWS water quality database, was also completed. These data will provide baseline information
for identification of potential future changes in groundwater levels and quality from increased
withdrawals, land-use changes, or climate change. Preliminary reports on potentiometric surface
mapping and groundwater quality will be available in April 2005.
(http://www.sws.uiuc.edu/gws/neilproj.asp)
Groundwater modeling in northeastern Illinois - Groundwater modeling activities for
northeastern Illinois continue to advance. Activities completed include creation of an interstate
geological framework, an interstate database of historical water withdrawals by aquifer, and an
aquifer hydraulic database for a regional three-dimensional computer model from the aquifers’
deepest layers of pre-Cambrian bedrock to the land surface. Models will be used to estimate
recharge rates, leakage between aquifers, and aquifer responses to increased aquifer development
and assess aquifer yields, assess surface water/groundwater interactions, evaluate alternative
management scenarios, and establish a framework for future modeling studies. Current
modeling efforts are principally focused on a regional model of the deep bedrock aquifer system
and a high-resolution model of shallow aquifers in Kane County. The shallow aquifer model is
based on three-dimensional geologic maps for Kane County and townships immediately
surrounding the county. Both models are in calibration phases; predictive modeling from the
regional model is expected before the end of 2005.
Mahomet aquifer and the Mahomet Aquifer Consortium - The Mahomet Aquifer
Consortium (MAC) is a grass-roots, not-for-profit organization whose goal is to manage the
Mahomet aquifer which is the major groundwater resource for east-central Illinois. Withdrawals
in 1995 for municipal use are estimated at over 30 million gallons per day (mgd). Withdrawals
for irrigation, principally in Mason and Tazewell Counties (the Havana Lowlands area), put
usage well over 100 mgd. Long-term observations of groundwater levels at Champaign show a
decline in artesian head of nearly 50 feet since 1950, as a result of increasing water demand in
the Champaign-Urbana area. Projections suggest that by 2020 population in the Mahomet
aquifer region may increase by 100,000 people. Illinois State Water Survey and ISGS scientists
serve as technical advisers to the consortium. In 2004, ISWS scientists measured water levels in
over 50 wells in Champaign and Vermilion Counties to better define the potentiometric surface
within and north of the Champaign-Urbana cone of depression. These data will be useful for
making improvements to and calibrating the ISWS’ digital flow model of the aquifer. The intent
of modeling is to examine the effects of increased development and to provide insight on
development alternatives (http://www.sws.uiuc.edu/gws/mahomet.asp).
Modeling aquifer heterogeneity: National Center for Supercomputing Applications
(NCSA) Fellowship - Fractured dolomite aquifers are one of a series of bedrock aquifers that are
part of the drinking water supply for the greater Chicago area. Groundwater flow and
contaminant transport in fractured rock systems are notoriously difficult to characterize because
the features conducting flow do not necessarily fill the available volume that porous media (e.g.,
sand and gravel) typically do. With support from the NCSA and Sandia Laboratories, research is
continuing on the characterization of these aquifers through the advanced analysis of simulated
hydraulic and tracer tests. The goal is to determine the relationship between the flow dimension
