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Water in sand and gravel deposits in McHenry County, Illinois

January 1, 1984

McHenry County, Illinois derives a major part of its ground-water supply from unconsolidated sand and gravel aquifers. Twenty-six public systems tap these aquifers for all or part of their supply. The county contains two types of sand and gravel aquifers--unconfined aquifers which are at or near the land surface, and semiconfined aquifers which are overlain by one or more till members. A map of water levels in unconfined and semiconfined aquifers shows that moraines and other topographically high features are ground-water divides of local flow systems. Distances from ground-water divides to discharge areas are a few miles or less. The quality of the ground water is good for most uses, although treatment may be required to reduce hardness (median concentration is 340 milligrams per liter) and dissolved iron (median concentrations is 140 micrograms per liter). Ground water is a calcium magnesium bicarbonate type. The range of specific conductance is from 260 to 1,170 micromhos. Values are higher near towns. (USGS)

Publication Year 1984
Title Water in sand and gravel deposits in McHenry County, Illinois
DOI 10.3133/wri834048
Authors J.R. Nicholas, J. T. Krohelski
Publication Type Report
Publication Subtype USGS Numbered Series
Series Title Water-Resources Investigations Report
Series Number 83-4048
Index ID wri834048
Record Source USGS Publications Warehouse