Formatted Title

Utilizing 3-D Data Visualization and Analysis (3DVA) to Construct a Conceptual Site Model and Select Future Boring Locations

Background/Objectives

Traditionally, conceptual site models (CSMs) have been presented as two-dimensional (2-D) representations, often lacking the depth and detail necessary to fully comprehend subsurface complexities. 3DVA allows for enhanced data integration, improved risk assessment, and superior communication with clients and regulators. As part of the pre-design and investigation phase of a Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) site, Earth Volumetric Studio (EVS) was used to analyze both historic groundwater chemistry and lithology as well as current site investigations using a membrane interface hydraulic profiling tool (MIHPT). 3DVA was utilized to construct a CSM and to assist with selection of future boring locations. These data were presented to regulators for discussion.

Approach/Activities

Historic data were of both a southern and central portion of an approximately 360-acre trichlorethylene (TCE) plume were compiled and analyzed. Lithologic data were assigned an integer value of zero through six to correspond with permeabilities of site facies. Higher permeable units like sands and gravels were assigned a lower integer number than silt and clay units. These data were imported into EVS and kriged in three dimensions via the Indicator Kriging functionality. The most recent 2023 TCE groundwater data from site monitoring wells were compiled and analyzed in 3-D. A semivariogram was selected and reviewed, then the data were visualized in 3-D based on standard kriging methodologies within EVS. The lithology and chemistry data were combined into a single view and analyzed for data gaps. The 3DVA was used to select MIHPT boring locations. During the installation of MIHPT borings, data were incorporated into the 3DVA in real time to confirm and inform possible future boring locations. Once the MIHPT borings were installed, electron capture detector (ECD) data were incorporated into the 3DVA and reviewed by regulators to assist in approval of proposed sonic boring locations. Sonic boring locations were installed at several MIHPT sites and samples of lithology, soil, and groundwater were collected. This data was incorporated into the 3DVA by indicator kriging for geology and standard kriging for TCE and reviewed by regulators to assist in updating the CSM and selection of an appropriate cleanup remedy.

Results/Lessons Learned

EVS is an extremely powerful tool for developing 3DVA and CSMs for sites. The 3DVA assisted in data gap identification as well as future boring selections. Visualization of both lithology and chemistry data were crucial in assesment of environmental impact. Visual representation of the complex site geology and chemstry made communicating these hazards to the client and regulators much simpler, allowing a more informed decision making process.