Geophysical Anomalies in the vicinity of Barton Springs and Determination of Groundwater Flow Path into the Barton Springs Pool, Austin, Texas

Abstract Barton Springs is a major discharge site for the Barton Springs Segment of the Edwards Aquifer and is in Zilker Park, Austin, Texas. Barton Springs consists of at least four springs. Barton Springs discharges into the Barton Springs Pool from the Barton Springs fault and from a cave beneath the water on the upthrown side of the fault, and several fissures. General groundwater flow paths to Barton Springs have been determined well by two decades of dye tracing studies. However, the location of the conduits containing the flow paths near the pool were not known accurately until this study. Reprocessing and reinversion of geophysical data, originally published between 2010 and 2014 by the author, with enhanced statistical parameters have confirmed significant anomalies located south of Barton Springs. The improved methodology increases the reliability of these findings. During December 18-20, 2018, Barton Springs started discharging plumes of turbidity flow into the pool. The source was attributed to being a geothermal drilling site at a residential neighborhood, which was located about ~4000 ft to the southwest of the pool. In addition, a newly drilled Barton Springs Edwards Aquifer Multiport well near the pool, February 2024, provided new insights about the geology of the Edwards Aquifer. Thus, the purpose of this paper is to integrate the results of geophysical work with the sediment-plume release data and subsurface data from the Multiport well and boreholes to better characterize groundwater flow in the vicinity of the Barton Springs and to “ground truth” the geophysical data.