Fortuitous Turbidity Flood at Main Barton Spring (Austin, TX) and its groundwater Implications and Correlation with Published Geophysical Results
Mustafa Saribudak
Principal Geophysicist-Geologist at Environmental Geophysics Associates, Ph.D.
Hello Karst Fans: Several months ago Main Barton Spring in Austin, Texas, started discharging plumes of turbidity flows into the Barton Springs swimming pool (BSSP) (see Figure 1). Within couple days, the source was found to be a drilling site less than a mile to the west of the pool. During the drilling operation, several wells were drilled into the karstic Edwards Aquifer. A site assessment study, completed by the Barton Springs/Edwards Aquifer Technical Team concluded that a void was encountered at a depth of 240 ft (73 m), and was assumed to be connected to a conduit flowing to the pool. And they approximately projected the groundwater flow direction from the drilling site into the BSSP-see the light blue, dashed-arrow in the southwest corner of the attached Google map (Figure 2).
We had done extensive pro bono geophysical work in the south, southwest part of the BSSP within the last 10 years, and discovered significant anomalies (conduits and faults). We published our findings in journals https://www.researchgate.net/publication/257797057_Geophysical_signatures_of_Barton_Springs_Parthenia_Zenobia_and_Eliza_of_the_Edwards_Aquifer_Austin_Texas
We took some of self potential (SP) and resistivity imaging anomaly locations from two published papers and superimposed them onto the Google Earth map of the study area to highlight the orientation and geometry of the anomalies (Figure 2). High SP and low resistivity anomalies (blue in color) indicate the conduit anomalies. Note that the groundwater flow direction estimated from the 2019 turbidity discharge aligns itself quite well with the positions of the geophysical anomalies. The geophysical data elaborates the path of the conduit into the pool. Enjoy it! PLEASE stay safe and healthy!
Figure 1. Turbidity flow in the Main Barton Spring swimming pool.
FIGURE 2. Correlation of geophysical anomalies with the orientation of the turbidity flow projected from the drilling data. High SP and the low resistivity values (dark blue colors) indicate the karstic anomalies (conduit, water-filled cave). Note that the low resistivity anomaly does not extend further east. Thus the groundwater flow in the conduit, shown with the dashed-red color, takes a bend to the north toward the swimming pool.