Investigation of the Hyporheic Zone at the 300 Area,Hanford Site [electronic resource].
- Washington, D.C. : United States. Dept. of Energy, 2007. and Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy.
- Physical Description:
- Additional Creators:
- Pacific Northwest National Laboratory (U.S.), United States. Department of Energy, and United States. Department of Energy. Office of Scientific and Technical Information
- The Remediation Task of the Science and Technology (S&T) Project is intended to provide research to meet several objectives concerning the discharge of groundwater contamination into the river at the 300 Area of the Hanford Site. This report serves to meet the research objectives by developing baseline data for future evaluation of remedial technologies, evaluating the effects changing river stage on near-shore groundwater chemistry, improving estimates of contaminant flux to the river, providing estimates on the extent of contaminant discharge areas along the shoreline, and providing data to support computer models used to evaluate remedial alternatives. This report summarizes the activities conducted to date and provides an overview of data collected through July 2006. Recent geologic investigations (funded through other U. S. Department of Energy (DOE) programs) have provided a more complete geologic interpretation of the 300 Area and a characterization of the vertical extent of uranium contamination. Extrapolation of this geologic interpretation into the hyporheic zone is possible, but there is little data to provide corroboration. Penetration testing was conducted along the shoreline to develop evidence to support the extrapolation of the mapping of the geologic facies. In general, this penetration testing provided evidence supporting the extrapolation of the most recent geologic interpretation, but it also provided some higher resolution detail on the shape of the layer than constrains contaminant movement. Information on this confining layer will provide a more detailed estimate of the area of river bed that has the potential to be impacted by uranium discharge to the river from groundwater transport. Water sampling in the hyporheic zone has provided results that illustrate the degree of mixing that occurs in the hyporheic zone. Uranium concentrations measured at individual sampling locations can vary by several orders of magnitude depending on the river and near-shore aquifer elevations. It is shown in this report that the concentrations of all the measured constituents in water samples collected from the hyporheic zone vary according to the ratio of groundwater and river water in the sample. One important aspect of this is that specific conductance provides a sensitive indicator of the relative contribution of groundwater and river water in a particular sample. This is because of the large difference is specific conductance of groundwater (~400 μS/cm) and river water (~130 μS/cm). It appears that in the hyporheic zone, advection of contaminates occurs very quickly, and variations in concentrations are a function of dilution rather than any chemistry effects caused by the difference in water chemistry between groundwater and river water.
- Published through SciTech Connect., 10/01/2007., "pnnl-16805", "830403000", and Gilmore, Tyler J.; Bunn, Amoret L.; Patton, Gregory W.; Kohn, Nancy P.; Mackley, Rob D.; Fritz, Brad G.; Mendoza, Donaldo P.; Arntzen, Evan V.; McFarland, Doug.
- Funding Information:
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