The role of a perched aquifer in contaminant transport at a proposed Superfund site on the southern high plains of Texas

Conference · Wed Jan 01 04:00:00 EST 1992 · Geological Society of America, Abstracts with Programs; (United States)

OSTI ID:5903306

Mullican, III, W F; Fryar, A E ^[1]

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1. Univ. of Texas, Austin, TX (United States). Bureau of Economic Geology

Hydrogeologic and hydrochemical investigations of a perched aquifer above the Ogallala aquifer are being conducted in the region of the US Pantex Plant, a proposed Superfund site, located approximately 20 mi northeast of Amarillo, Texas. Since the early 1950's, a small playa basin located on the Pantex Plant has been used as a wastewater discharge pond with daily discharge rates ranging from 400,000 to 1,000,000 gallons. Measured depths to the perched aquifer range from 210--300 ft below land surface, whereas depth to the regional Ogallala aquifer represents a ground-water mound, with the peak of the mound underlying the small playa basin. Solute concentrations tend to decrease outward from the center of the ground-water mound. Down the hydrologic gradient the composition of perched ground water appears to evolve toward that of the regional Ogallala aquifer. Tritium concentrations in the perched aquifer reached as high as 8.75 TU, indicating water younger than 40 yr. old. Modeling of the perched aquifer is focusing on how much, if any, discharge to the small playa basin has enhanced recharge to the perched aquifer and increased the vertical and lateral extent of the perched aquifer. Hydrogeologic and hydrochemical data illustrate how the perched aquifer is diverting the downward vertical migration of potential contaminants laterally away from the small playa basin. Accurate delineation of rates and flow directions and understanding the hydrochemical evolution of ground water in the perched aquifer are critical to any successful remediation effort.

• OSTI ID: 5903306
• Report Number(s): CONF-921058--
• Conference Information: Journal Name: Geological Society of America, Abstracts with Programs; (United States) Journal Volume: 24:7
• Country of Publication: United States
• Language: English

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AQUIFERS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CHEMISTRY
DEPTH
DEVELOPED COUNTRIES
DIMENSIONS
FLOW MODELS
GEOCHEMISTRY
GROUND DISPOSAL
GROUND WATER
HYDROGEN COMPOUNDS
HYDROGEN ISOTOPES
HYDROLOGY
ISOTOPES
LIGHT NUCLEI
LIQUID WASTES
MANAGEMENT
MATHEMATICAL MODELS
NATIONAL ORGANIZATIONS
NORTH AMERICA
NUCLEI
ODD-EVEN NUCLEI
OXYGEN COMPOUNDS
PANTEX PLANT
PLANNING
RADIOISOTOPES
REMEDIAL ACTION
SOLUTES
TEXAS
TRITIUM
US DOE
US ERDA
US ORGANIZATIONS
USA
WASTE DISPOSAL
WASTE MANAGEMENT
WASTE WATER
WASTES
WATER
YEARS LIVING RADIOISOTOPES