Availability of Ground Water in Wayne County, Iowa

Information is presented on the availability and quality of ground water in Wayne County, one of several counties in southern Iowa affected by a shortage of good-quality water. The data indicate that only locally and in limited areas, or only after extensive water-quality treatment, are suitable supplies of ground water available to satisfy the water needs in the county. Bedrock aquifers yield variable amounts of moderately to highly mineralized water. Upper bedrock units at depths of about 200 to 1,000 feet yield up to 50 gpm (gallons per minute) to individual wells; however, the dissolved-solids content of the water ranges from about 2,000 to 5,500 mg/1 (milligrams per liter). Lower bedrock units at depths of 2,500 to 2,800 feet are believed capable of furnishing from 300 to 800 gpm to individual wells, but the dissolved-solids content of the water ranges from 800 to 2,500 mg/1. Surficial aquifers comprising glacial drift and alluvium are estimated to yield up to 45 gpm in some areas; an availability map indicates the areas where water supplies can be developed from these deposits. The chemical quality of water from the surficial aquifers varies considerably; dissolved-solids concentrations range from about 470 mg/1 in the alluvium to over 3,600 mg/1 in the deep (more than 100 feet) glacial drift. Many shallow (100 feet or less) supplies presently in use contain high concentrations of nitrate and chloride, and these concentrations are attributed to localized contamination. Wells in the alluvium and shallow drift that are properly constructed and located are expected to yield satisfactory quality water.