Enhanced 3-D Visualization as a Data Analysis Tool in Remediation Hydrogeology

Three-dimensional subsurface visualization techniques are well developed and have proven to be a powerful data analysis tool for many geosciences applications; however, they continue to be underutilized by environmental practitioners. While conventional two-dimensional methods are commonly employed, only a full three-dimensional analysis can reveal the spatial correlations that are critical for conceptual site model development. The use of Environmental Visualization System (EVS) software to integrate geologic, hydrologic and geochemical data into a comprehensive, three-dimensional framework, provides a more thorough evaluation of multiple coincident data types. Lithologic data obtained during visual soil logging, cone penetrometer testing (CPT), hydraulic profiling testing (HPT), and membrane interface probe (MIP) investigations, as well as conventional geophysical logging, are used to develop lithologic and hydrostratigraphic models. Contaminant data such as quantitative analytical results from water quality and  soil  sampling, as well as qualitative results from MIP and other high-resolution techniques such as rapid optical screening tool / laser-induced flourescence (ROST/ LIF) are used to delineate source areas, plume extent and migration pathways. Geologic and hydrogeologic  information such as orientations of bedding and major fracture sets and faults, hydraulic head and gradient, mobile and immobile porosity, soil bulk density and moisture content, can be utilized in combination with lithologic and contaminant data to identify predominant groundwater migration pathways and zones of high contaminant mass flux. Though several challenges have been identified through the use of EVS, three-dimensional analysis should be more widely applied in remediation hydrogeology because it cost-effectively supports improved site characterization and remedy design and implementation. Four case studies are provided that demonstrate the utility and flexibility of this tool.