Water quality in the St. Peter aquifer generally is suitable for most uses. Dissolved solids concentrations range from about 200 to 950 mg/L, with highest concentrations in the southwest where overlying Cretaceous deposits are a source of highly mineralized leakage. The aquifer is well protected from surface sources of contaminants except locally along the east side of the area where the overlying drift is less than 50 ft thick. The Decorah-Platteville-Glenwood confining bed overlies about 80% of the St. Peter, and drift overlies the remainder. Water in the St. Peter aquifer generally flows toward the Mississippi River and its tributaries. Some of the water flows southward into Iowa from a groundwater divide in Dodge and Steele Counties. Well yields from the aquifer are generally adequate for most uses. The aquifer is part of a sequence of sedimentary bedrock units that was deposited in Paleozoic seas that occupied a shallow depression known as the Hollandale embayment. The aquifer, which consists of light yellow or white, fine- to medium-grained, well-sorted sandstone, ranges from about 100 to 150 ft in thickness. (USGS)
Additional publication details
USGS Numbered Series
Hydrogeologic and water-quality characteristics of the St. Peter aquifer, Southeast Minnesota
Water-Resources Investigations Report
13 maps on 2 sheets ; 27 x 26 cm. and smaller, sheets 88 x 102 cm., folded in envelope 31 x 24 cm.