GSA Annual Meeting in Phoenix, Arizona, USA - 2019

Paper No. 33-13
Presentation Time: 9:00 AM-5:30 PM


MCGILL, Ashley, WONG, Stephanie S. and YELDERMAN Jr., Joe C., Geosciences, Baylor University, One Bear Place #97354, Waco, TX 76798

A common way to analyze aquifer sustainability is to use average annual rainfall to produce average annual recharge. Although this may suffice for certain studies, it leaves data uncalculated in regard to timing and magnitude of both rainfall and hydrologic response. Specifically, the complete atmospheric picture leading to recharge events remains unclear. In areas such as central Texas, strong seasonality results in varying stress levels on aquifers, which directly relates to varying demands for water. While groundwater systems are known to recharge from rainfall, there is little published literature linking which storm types produce the most rainfall leading to aquifer recharge. Making this connection requires analysis of both National Oceanic and Atmospheric Administration (NOAA) historical data from the area as well as stream gauge and groundwater data. Understanding recharge with the addition of meteorological comprehension provides greater insight to aquifer dynamics such as what time of year recharge is greater, and more interestingly, why.

To ensure the most accurate representation of meteorological conditions, interpretation of diverse data sets is imperative. In this study, Meteorological Terminal Aviation Routine Weather Reports (METARs) from aerodromes surrounding the Salado Creek watershed of the Edwards Balcones Fault Zone aquifer were analyzed to determine storm timing and source type for each measured precipitation event gathered from the National Centers for Environmental Information (NCEI) Record of Climatological Observations Stations within the area of interest. Storm identities from each of these precipitation events, alongside rainfall quantity estimations from Weather Surveillance Radar-1988 Doppler (WSR-88D) data published by the National Weather Service (NWS) Next Generation Weather Radar (NEXRAD) program, were compared against USGS stream gauge data and groundwater levels to better understand the relationship between the magnitude of precipitation events resulting in hydrological response. Preliminary results indicate a clear seasonality for storm type occurrence. Information gained through the utilization of differing data sets provides insight into which storm types result in aquifer recharge as well as the time of year when most recharge occurs.