The Mount Simon-Hinckley aquifer comprises a thick sequence of sandstone, siltstone, and shale that underlies southeast Minnesota. It is an important aquifer in the Hollandale embayment and in the populous Twin Cities metropolitan area, where it supplies about 10 percent of the groundwater used. Withdrawals increase significantly north of the Twin Cities basin, but some additional development of water supplies is still possible. Yields to wells are generally about 500 gallons per minute but may be as much as 2,000 gallons per minute locally. Dissolved-solids concentrations are slightly lower than in water from other aquifers in the Hollandale embayment and range from about 100 milligrams per liter in the north to as much as 2,400 milligrams per liter in the south. Dominant water type is calcium magnesium bicarbonate; however, sodium chloride-type water is found at depth. Water from the aquifer locally contains iron and manganese in concentrations greater than 1 milligram per liter. (USGS)
Additional publication details
USGS Numbered Series
Hydrogeologic and water-quality characteristics of the Mount Simon-Hinckley aquifer, southeast Minnesota
Water-Resources Investigations Report
12 maps on 2 sheets ; 27 x 26 cm., sheets 89 x 101 cm. and 102 x 89 cm., folded in envelope 30 x 24 cm.