LITHOFACIES INTERPRETATION OF SYSTEMATIZED BOREHOLE GEOLOGIC DATA

Simulations of vadose zone flow and transport are a fundamental component of studies aimed at determining the extent of waste contamination and movement beneath the Hanford Site. Historically, these simulations and models have represented the geologic framework and associated flow and transport properties through simple homogenous and horizontally stratified hydrogeologic units. Capturing the heterogeneity, small scale variability, and uncertainty within models is receiving more emphasis due to increasing capabilities of computer systems and the need to develop more detailed and complete depictions of contaminant transport. The ability to improve resolution of models and simulations is limited by the availability of data in a form favorable to computer processing. Geologic borehole information is, for the most part, qualitative in nature and not readily amenable to numerical analysis. Thus, efforts are being made to systematize borehole geologic data, to be used in a more quantitative manner. Detailed procedures have been developed to translate qualitative descriptive information into discrete semi-quantitative parameters, and to translate inconsistent quantitative and semi-quantitative data sets into common parametric data sets. A geologic data management system is being developed to manage these new “translational” data sets and integrate them with existing databases to support their synergistic analysis and improved numerical representation of the subsurface geology. Detailed procedures and uniformed translational processes allow for qualitative data from a variety of sources to be represented in a semi-quantitative and computer accessible form that is thorough, uniform, traceable, and defensible. This process has led to the creation of a detailed representation of the geologic relationship between flow and transport properties of lithofacies and the stratigraphic sequence of those lithofacies beneath the waste disposal facilities at the Hanford Site.