GEOPHYSICAL VS. TRADITIONAL HYDROGEOLOGIC INVESTIGATIONS: MAKING DIFFERENT SCALES AND METHODS WORK TOGETHER

Geophysical studies, primarily in the form of airborne electromagnetic (AEM) surveys, have provided useful data for localized hydrogeologic investigations throughout Nebraska over the last seven to eight years, but the data they generate is not commonly incorporated into regional conceptual and numerical models. We highlight the inherent differences in methods, data sets, and end products between a 2,200 km² (850 mi²) county groundwater atlas prepared using traditional bore hole data and a 285 km² (110 mi²) AEM survey within a portion of the same area. Comparison of the two studies reveals several ways in which geologists may enhance the applicability of AEM surveys to regional hydrogeologic investigations: 1) analyze traditional data sets far beyond the AEM study area at a scale that will allow seamless integration of the two, and include those data sets and methodologies with the deliverable; 2) use the AEM results to develop new hypotheses for the interpretation of borehole data in areas where that data is sparse, 3) describe in detail what additional data should be collected to convert AEM data to hydrogeologic parameters such as hydraulic conductivity or amount of water in storage; and 4) provide case studies of how similar geophysical studies have been leveraged in regional hydrogeologic investigations.