NewsDrop Winter 2022

EAA Aquifer Data Analyst II, Logan Schmidt, and two graduate students from UTSA, log and characterize rock chip samples from a borehole drilling.

An EAA scientists holds out a “rock chip tray.” Each pocket of the tray represents a drilling depth and composition of five feet.

A low rumble sounds as a drill bit rapidly churns, erupting rock chips and dust from a strategically placed borehole at the EAA’s Field Research Park. EAA scientists and graduate students from the University of Texas at San Antonio look on, eagerly awaiting the rig operator’s delivery of the next sample of rock extracted from the drilling process 25-feet below the ground surface, near the bottom of the borehole. The completed 30-foot boreholes represent a window into the vadose zone, the area below the ground surface and above the water table of the aquifer. EAA scientists intend to use the boreholes to deploy geophysical tools including nuclear magnetic resonance (NMR) to record hydrologic properties such as water content and void spaces. The scientists are interested in the direction and volume of water infiltrating the system, especially within the FRP land management demonstration area. The boreholes are being installed upgradient, within, and downgradient of land management practices in

the demonstration area to help quantify the potential benefits of land management as a conservation practice. The drilling process provides an opportunity to characterize the rock cuttings in different drilling intervals and prepare samples for laboratory analyses. The drill momentarily halts its methodical churning, as the operator collects a one gallon sample bag worth of rock cuttings. The scientists and students collect the bag and split the sample to begin logging and characterizing the tiny fragments, bringing them one step closer to answering research questions about the geologic character and conceptual framework of the vadose zone at the FRP.

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