Ground-water levels and flow at selected study sites in the Walnut Creek Management System Evaluation Area, Boone and Story counties, Iowa, 1991-93

Data collected from May 1991 through September 1993 to determine seasonal fluctuations in ground-water levels and to estimate directions of ground-water flow in the saturated zone at selected study sites at the Iowa Management Systems Evaluation Area in the Walnut Creek Watershed are presented. The Walnut Creek Watershed is located on glacial deposits of Wisconsinan age in central Iowa and includes about 20 square miles. The upper glacial materials appear to be supraglacial tills rather than basal glacial tills and contain both oxidized and unoxidized zones. Water levels were measured in 102 wells from 38 locations at 7 study sites in the watershed. Water levels fluctuated in response to local climatic conditions and ranged from at or near the land surface to more than 30 feet below land surface. In general, ground water flowed towards Walnut Creek or large drainage tiles. Potentiometric-surface maps at the selected study sites can be used to determine which locations might be affected by agricultural management practices in place at each site.