INVESTIGATING RECHARGE DYNAMICS OF THE ARBUCKLE-SIMPSON AQUIFER THROUGH TEMPORAL ELECTRICAL RESISTIVITY IMAGING

The Arbuckle-Simpson Aquifer (ASA) is a highly fractured karst system located in south-central Oklahoma, serving as the sole-source water supply for several municipalities, including Ada, Oklahoma. Byrds Mill Spring (BMS), the primary water source for Ada, exhibits continuous rhythmic flow patterns influenced by natural recharge processes. Two losing streams situated west and southwest of the spring display evidence of subsurface recharge structures. These recharge zones are under investigation to understand and define their functionality and flow pathways. During the summer of 2024, six temporal electrical resistivity imaging (TERI) lines were installed in and around the recharge structures along the streambeds. These lines enable resistivity data collection approximately bi-monthly and during overland flow events. The geophysical data is processed to produce two-dimensional subsurface resistivity profiles, revealing structural and hydrological characteristics of the recharge zones. Previous studies suggest that large storm events significantly impact BMS; however, the specific locations and mechanisms by which water enters the subsurface remain unclear. To address this, the current TERI installations will be complemented by hydrographs derived from Solinst Levelogger 5 LTC™ devices, planned for deployment in winter 2025, and chemical analyses of water samples. These integrated methods aim to provide a comprehensive understanding of the hydrological and geochemical dynamics along the streambeds. The findings will inform the City of Ada Managed Aquifer Recharge Research (CAMARR) program, contributing to the design and implementation of artificial recharge structures near BMS. This work has the potential to enhance the sustainability and resilience of the ASA as a critical water resource.