Geohydrology and water quality of Kalamazoo County, Michigan, 1986-88
Dataset Identification:
Resource Abstract:
<p>Thick, glacial sand and gravel deposits provide most ground-water supplies in Kalamazoo County. These deposits range in
thickness from 50 to about 600 feet in areas that overlie buried bedrock valleys. Most domestic wells completed at depths
of less than 75 feet in the sands and gravels yield adequate water supplies. Most industry, public supply, and irrigation
wells completed at depths of 100 to 200 feet yield 1,000 gallons per minute or more. The outwash plains include the most productive
of the glacial aquifers in the county. The Coldwater Shale of Mississippian age, which underlies the glacial deposits in most
of the county, usually yields only small amounts of largely mineralized water. </p><p>Ground-water levels in Kalamazoo County
reflect short- and long-term changes in precipitation and local pumpage. Ground-water levels increase in the spring and decline
in the fall. </p><p>Ground-water recharge rates, for different geologic settings, were estimated from ground-water runoff
to the streams. Recharge rates ranged from 10.86 to 5.87 inches per year. A countywide-average ground-water recharge rate
is estimated to be 9.32 inches per year. </p><p>Chemical quality of precipitation and dry fallout at two locations in Kalamazoo
County were similar to that of other areas in the State. Total deposition of dissolved sulfate is 30.7 pounds per acre per
year, of total nitrogen is 13.2 pounds per acre per year, and of total phosphorus is 0.3 pounds per acre per year. Rainfall
and snow data indicated that the pH of precipitation is inversely proportional to its specific conductance. </p><p>Water of
streams and rivers of Kalamazoo County is predominately of the calcium bicarbonate type, although dissolved sulfate concentrations
are slightly larger in streams in the southeastern and northwestern parts of the county. The water in most streams is hard
to very hard. Concentrations of dissolved chloride in streams draining urban-industrial areas are slightly larger than at
other locations. Concentrations of total nitrogen and total phosphorus in streams are directly proportional to streamflow.
Except for elevated concentrations of iron, none of the trace elements in streams exceeded maximum contaminant levels for
drinking water established by the U.S. Environmental Protection Agency. Pesticides were detected in some streams. </p><p>Ground
water in the surficial aquifers is of the calcium bicarbonate type, although sodium, sulfate, and chloride ions predominate
at some locations. Specific conductance and hardness and concentrations of total dissolved-solids slightly exceed statewide
averages. Concentrations of dissolved sodium and dissolved chloride in 6 wells were greater than most natural ground waters
in the State, indicating possible contamination from road salts. Water samples from 6 of the 46 wells sampled contained concentrations
of total nitrate as nitrogen greater than 10.0 milligrams per liter. Elevated concentrations of total nitrate as nitrogen
in water from wells in rural-agricultural areas probably are related to fertilizer applications. Results of partial chemical
analyses by the Michigan Department of Public Health indicates specific conductance, and concentrations of hardness, dissolved
fluoride, and total iron are fairly uniform throughout the county. Concentrations of dissolved sodium, dissolved chloride,
and total nitrate as nitrogen differed among townships. Pesticides were detected in water from only one well. Water from five
wells contained volatile organics. </p><p>A map of susceptibility of ground water to contamination in Kalamazoo County was
developed using a system created by the U.S. Environmental Protection Agency. Seven geohydrologic factors that affect and
control ground-water movement are mapped and composited onto a countywide map. All seven factors have some effect on countywide
susceptibility, but the most important factors are depth to water and composition of the materials above the aquifer.</p>
Citation
Title Geohydrology and water quality of Kalamazoo County, Michigan, 1986-88