Three-dimensional Hydrostratigraphy of the Swedeburg, Nebraska Area: Results from Helicopter Electromagnetic (HEM) Mapping for the Eastern Nebraska Water Resources Assessment (ENWRA) CB-5(NS), Dana P. Divine and Jesse T. Korus, 38 pp., size 8.5" x 11". 2013. Description: Groundwater resources under much of eastern Nebraska are contained within or beneath Quaternary glacial deposits. The heterogeneity and complexity of these deposits have hindered efforts to characterize them in detail. Test-hole drilling alone is not effective for mapping these units over large regions, but in certain settings, borehole data can be integrated with geophysical methods to map hydrostratigraphic units at high resolution and in three-dimensions. This study integrates test hole drilling and Helicopter Electromagnetic (HEM) surveys to characterize the hydrostratigraphy of an area around Swedeburg in eastern Nebraska. Helicopter Electromagnetic (HEM) surveys were flown in 2007 at three pilot study sites in eastern Nebraska as part of the ongoing Eastern Nebraska Water Resources Assessment (ENWRA), a collaborative study between six of Nebraska's Natural Resources Districts, the Conservation and Survey Division (CSD) of the School of Natural Resources at the University of Nebraska-Lincoln, the Nebraska Department of Natural Resources (DNR), and the United States Geological Survey (USGS). The rationale and history behind ENWRA are outlined in Divine et al. (2009). The purpose of the pilot studies was to assess the effectiveness of HEM at mapping the complex geology of Quaternary alluvial and glacial deposits. The pilot studies were conducted at three sites that together encompass the wide range of hydrogeologic settings in eastern Nebraska. The results of the pilot studies prompted resource managers to survey a 73 square-kilometer (28 square-mile) area around Swedeburg in Saunders County (Fig. 1). The results of the Swedeburg study are presented herein. Print on demand, color copy available.