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Full-Text Articles in Physical Sciences and Mathematics
Residence Times Of Minnesota Groundwaters, Scott C. Alexander, E. Calvin Alexander Jr.
Residence Times Of Minnesota Groundwaters, Scott C. Alexander, E. Calvin Alexander Jr.
Journal of the Minnesota Academy of Science
ABSTRACT-Tritium, 14C, and nitrate analyses for eighty groundwater samples from selected Minnesota aquifers indicate a range of residence times from a few days or weeks to tens of thousands of years. The presence of significant nitrate contamination in groundwater is confined to recent or mixed groundwaters. Isotopic studies can yield information that will be useful in the design of effective groundwater protection plans in Minnesota.
Factors Affecting Water-Supply Potential Of The Twin Cities Metropolitan Area Aquifer System, Michael E. Schoenberg
Factors Affecting Water-Supply Potential Of The Twin Cities Metropolitan Area Aquifer System, Michael E. Schoenberg
Journal of the Minnesota Academy of Science
ABSTRACT-The Twin Cities aquifer system in Minnesota contains five aquife~s and fou: confining units that together consist of fourteen geologic units. Unconsolidated sand and gravel aqmfers overlie bedrock sandstone and carbonate aquifers. Between 1880 and 1980, groundwater wi_thdrawals have c_aused long-term wate~ level declines of as much as 90 feet in the Prairie du Chien-Jordan aquifer and 240 feet m the deeper Mount S~monHinckley aquifer-the two major sources of groundwater supplies in the ar~a .. The estimated max1mu1:1 continuous withdrawal rate from the aquifer system is about 650 Mgal/d (million gallons per day). This compares with an average daily groundwater …