LITHOFACIES MAPPING AT THE HANFORD SITE - DATA MANAGEMENT, ANALYSIS, AND VISUALIZATION

Prediction of contaminant flow and transport is critical to remediation of contaminated sites. Flow and transport models typically require parameterization at grid block scales ranging from 0.1 m to 10's of m, depending on the dimensionality and size of the problem domain. Information on the spatial distribution and heterogeneity of the subsurface properties that control flow and transport is often very limited. However, understanding of the sedimentary geology and particularly the spatial distribution of lithofacies can be used to constrain estimates on the spatial distribution and heterogeneity of key subsurface properties.

Borehole data are the cornerstone of subsurface characterization, monitoring, and performance assessment programs. These data often take great effort and expense to generate. Yet, historically they have been managed in an ad hoc fashion, using a wide variety of formats (generally non-digital) and scattered across individual project records. The Groundwater Remediation Project is developing an integrated borehole geology data management, analysis, and visualization system to maximize the value of these data. HBGIS (Hanford Borehole Geologic Information System) is a secure online web application designed to connect directly to several existing databases and facilitate data export to a variety of commercially available or specialized data processing applications.

Visualization and analysis of multiple borehole geologic data sets in concert with outcrop studies and basin-wide sedimentary geologic modeling provides the foundation for estimating the spatial distribution of lithofacies. Petrophysical and geochemical analyses of samples from key lithofacies provide the data sets with which to derive the parametric probability-distribution functions for the petrophysical and geochemical properties, as well as the spatial correlations (i.e., heterogeneity, anisotropy) within each lithofacies. Thus, by estimating the spatial distribution and the parametric properties within each lithofacies, we have been able to improve the resolution and spatial distribution of critical flow and transport properties at a plutonium and carbon tetrachloride contaminated site.