Browsing by Subject "groundwater contamination"

Now showing 1 - 3 of 3
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    Airborne and Ground-Based Geophysical Screening of Potential Brine Infiltration Sites, Runnels County, Texas
    (1997) Paine, Jeffrey G.; Dutton, Alan R.; Blum, Martina U.
    Salinization of soil, surface water, and groundwater is a chronic environmental and agricultural problem in many parts of Texas. In this study of a 91 km^2 area near Ballinger in Runnels County, Texas, we integrated results from high-resolution airborne and ground-based geophysical surveys, water and soil sampling, and chemical analyses to locate near-surface concentrations of saline water and determine their origin. Possible salinity sources are upward movement of brine along natural conduits (faults, fractures, joints, and permeable stratigraphic units), downward migration from surface brine pits, leaking oil and gas wells, and evaporative concentration of shallow groundwater as a result of agricultural practices. A prime goal of the study was to determine the effectiveness of the method in locating leaking wells and distinguishing them from other salinity sources. This project represents a coordinated and cooperative effort between the Railroad Commission of Texas (RRC), the Bureau of Economic Geology (BEG) and its airborne geophysical subcontractor Dighem I-Power, the Lower Colorado River Authority (LCRA), and the Colorado River Municipal Water District (CRMWD).
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    Evaluation of the Potential for Cross Contamination of the Edwards Aquifer from Dissolved Contaminants in the Shallow Groundwater Zone in the Vicinity of Kelly AFB via Faults and Wells
    (2002) Hovorka, Susan D.; Paine, Jeffrey G.; Reedy, R. C.
    Shallow groundwater in alluvial sediments in southwest San Antonio has been impacted by urban and industrial activities. The shallow groundwater zone overlies an interval characterized as an aquitard, which in turn overlies the Edwards aquifer. The Edwards aquifer is a highly transmissive hydrologic unit that supplies drinking water to the city of San Antonio, as well as diverse other users downstream. The purpose of this study is to assess the risk that contaminated water can move across the aquitard from the shallow groundwater zone into the Edwards aquifer. The study area is defined by a polygon that includes the Kelly Air Force Base, east Kelly area, and the contaminant plumes mapped by Miller (2000). The most significant conditions with potential to transmit contaminants from the shallow groundwater zone to the Edwards exist at times when a hydrologic gradient is present between the two zones and at places where a pathway having significant permeability connects them. In this study, we assessed the hydraulic gradient between the shallow groundwater zone and the Edwards aquifer. We analyzed faults and water wells as potential pathways having significant permeability through the aquitard. The gradient between the Edwards and the shallow groundwater in the study area varies spatially and temporally. Likelihood of a downward hydraulic gradient is suggested over the northwestern half of the study area during the lowest 25% of water levels in the Edwards aquifer. During average and high water levels in the Edwards aquifer, there is no downward gradient between the shallow groundwater and the Edwards in the study area.
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