TRANSIENT ELECTRICAL RESISTIVITY IMAGING OF AN ENHANCED AQUIFER RECHARGE SITE

Enhanced Aquifer Recharge (EAR) is the process of enhancing the natural conveyance of water into the subsurface to augment water supplies. Karst geology offers a natural mechanism for recharge and covers 20% of the U.S. land surface. The potential impacts to groundwater flow following the use of EAR in karst geology is highly variable and poorly understood. This case study will demonstrate the use of transient electrical resistivity imaging (TERI) to investigate groundwater flow along a fault beneath an EAR study site following overland flow recharge events. Previous work at this EAR study site identified flow zones beneath the site to determine where connections exist between shallow and deep groundwater. One goal of this research effort is to demonstrate the use of geophysical tools for understanding the movement of water in an EAR system in a karst environment. One-time ERI surveys measure the bulk resistivity at that time, whereas the collection of time-lapse images of pre- and post-precipitation will improve our understanding of groundwater flow by capturing active recharge. This presentation shares preliminary findings from precipitation events in the Arbuckle Simpson Aquifer in Spring and Summer of 2021.