The Areal Extent and Hydraulic Continuity of Perched Ground Water in the Vicinity of the Pantex Plant


Groundwater contamination at the Pantex Plant is currently restricted to a perched aquifer(s) above the regional Ogallala aquifer water table. Therefore, the areal extent and hydraulic continuity of this unit are critical factors in the overall hydrologic characterization required for the design of effective remediation activities. Another important question is determining whether any privately owned domestic wells are producing from the perched aquifer(s) in areas downgradient from and hydrologically connected to known or possible contaminated areas on the Pantex Plant. It should be noted, however, that a continuous saturated zone is not the only scenario by which point-source and non-point-source contaminants could migrate. All recharging groundwater that is perched will eventually move through the fine-grained, low-permeability zone that underlies the perched aquifer(s) and resume a downward track to the Ogallala aquifer. In addition, the results of this study clearly illustrate areas where there is no perched aquifer(s), and thus there may be no perching layer, within the boundary of the Pantex Plant. In these areas where a perching layer is absent, there will be no retarding effect created by the perched aquifer(s) on the vertical movement of recharge to the Ogallala aquifer.


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