M.S. (Master of Science)
Department of Geology
Hydrogeology--Illinois--De Kalb County; Groundwater--Illinois--De Kalb County; Water chemistry; Geochemistry--Illinois--De Kalb County
A preliminary groundwater investigation was completed in northern DeKalb County, Illinois to examine the influence of the buried Troy Bedrock Valley on the local groundwater flow system. This study incorporated geologic, groundwater level, and water chemistry information to determine the local effects of this buried bedrock valley. The data were compiled from previous studies, drillers' records, water-level measurements from 45 private wells, and water samples collected from wells across the study area. This information was integrated to 1) construct a revised version of the bedrock topography, 2) classify the bedrock and glacial sediments within a hydrostratigraphic framework, 3) produce water-level maps of the Galena-Platteville Unit, and 4) approximate groundwater recharge zones into the bedrock aquifer. The upper weathered and fractured portion of the Galena-Platteville Unit is the most utilized aquifer in the study area, although smaller quantities of water are also available from permeable lenses of sand and gravel distributed throughout the glacial drift. Water-level data measured from these aquifers show that groundwater flow is directed away from the bedrock uplands toward the center of the buried bedrock valley. These data also indicate that groundwater within the unconsolidated glacial sediments discharges into the Galena-Platteville Unit with the greatest groundwater contribution occurring along the bedrock uplands. The spatial distribution of the water quality results, as well as the waterlevel data, indicates the approximate locations of zones of recharge within the bedrock uplands. The variation in water chemistry across the study area indicates the influence of the flow path direction within the Galena-Platteville Unit. In particular, position with respect to recharge zones and lithology have been postulated to control sodium, calcium, magnesium, and bicarbonate in recognizable patterns.
Morrison, Jacqueline N., "Evaluation of the hydrogeology and groundwater geochemistry of the Troy Bedrock Valley in Northern DeKalb County, Illinois" (1996). Graduate Research Theses & Dissertations. 2943.
xii, 135 pages
Northern Illinois University
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