Developing a Novel Approach for Identifying Geologic Controls on Groundwater Flow

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Groundwater serves almost half the world’s population and irrigates 38% of agricultural land and there is increased strain on groundwater resource. In the United States, more effective management and remediation of the thousands of polluted groundwater sites will be critical. Managing these sites, responsibly and cost effectively, requires accurate description of the hydrostratigraphy, which describes the control that the distribution of different sediments and rocks in the subsurface has on groundwater flow. This research will develop a new approach that relies on collecting water levels in wells using a combination of leading-edge groundwater monitoring technologies to characterize hydrostratigraphy. The new approach will be tested at a field site where groundwater is contaminated by a mixture of organic chemicals. Student trainees will practice technical skills, science communication, project management skills, and learn to apply research results to inform site decisions. The groundwater monitoring technology from this research will be transferred to an outdoor teaching facility to provide students across the University of Iowa the opportunity to use the technology in their courses and undergraduate research. The goal of this research is to develop an approach to elucidate hydrostratigraphic units in the subsurface using a direct hydraulic dataset (i.e., water levels in wells). Water level data will be collected every 10 seconds from 10 to 15 distinct depths in the subsurface at every monitoring location using wells called multilevel systems. These data will show the response of water levels to changes in vertical groundwater flow during rainwater infiltration and/or changes in pumping. The response data will highlight the boundaries and thicknesses of distinct hydrostratigraphic units. Other complementary data sets and a computer model will be used to evaluate the accuracy of the hydrostratigraphy determined using this new approach and hydrostratigraphy developed using standard methods. The outcome will be the creation of an improved approach to characterizing hydrostratigraphy that is applicable to all groundwater settings. The findings will reduce uncertainty in simulations of groundwater flow and contaminant migration and provide a better basis for managing contaminated sites as demands on groundwater resources increase. This project is jointly funded by Hydrologic Sciences program, the Established Program to Stimulate Competitive Research (EPSCoR), and the Earth Sciences Instrumentation and Facilities program.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.