AEG EVENT 1/25/24: Development of Conceptual Site Models

ABSTRACT
As geologists we are used to thinking about subsurface data in 3-dimensions but until recently it has not been easy to create 3-d visualizations of subsurface data to use in data analysis, decision support, and to share with colleagues, clients, and other stake holders. My coworkers and I will show you an example to demonstrate how a 3-dimensional geologic model and conceptual site model are built in Leapfrog software using existing information such as geologic maps, cross sections, boring logs, natural gamma logs, water level data, and sample results in both PDF and electronic format. Using the Puchack Well Field Superfund site in New Jersey as an example, we will show you how a geologic model is created in Leapfrog and how data can be modelled to support decision making such as where to locate wells. At the Puchack site the lithostratigraphic geologic model has evolved over 20 years from paper to digital, from 2-dimensional to 3-dimentional, and now incorporates an environmental sequence stratigraphy based geologic model. The Puchack site is located just north of Camden, New Jersey, covers approximately 180 acres, and is underlain by the unconsolidated Potomac-Raritan-Magothy system to a depth of 300 feet. In the 1980s hexavalent chromium contamination in groundwater shut down the well field. The U.S. Environmental Protection Agency (USEPA) began a Remedial Investigation (RI) in 2000 and has been conducting remedial action at the site since about 2010. The project team has applied the geologic model of the site to ensure the correct placement of extraction, injection, and monitoring well screens which is critical to the success of the Remedial Action (RA). The RA involves the injection of sodium lactate (a reducing agent) in groundwater to reduce hexavalent chromium to trivalent chromium.
 
BIOGRAPHY

John N. Dougherty in a Professional Geologist and senior hydrogeologist at CDM Smith with a Bachelors in Geosciences from Penn State University. John has extensive experience applying a range of site characterization tools and drilling methods to the hydrogeologic characterization of groundwater contamination sites and is leading the application of ESS at CDM Smith. John uses gINT, Leapfrog, and Open Ground software to manage borehole data, to support real time decision making in the field, and to generate boring logs and cross sections. John was on the team that developed the Interstate Technology and Regulatory Council “Characterization and Remediation in Fractured Rock” guidance and was an instructor in the online training program from 2018 through 2022 when it was retired.

Morgan Simon is a Licensed Geologist at CDM Smith with a Masters in Applied Geoscience from University of Washington. Morgan assists in the characterization of groundwater and sediment contamination sites and assists John with the application of ESS at CDM Smith. Morgan is also a Leapfrog modeler at CDM Smith.

Thomas J. Cook has more than 30 years of experience as an environmental geologist specializing in site investigation and characterization. He leads CDM Smith’s practice for 3D data visualization and data analysis. With extensive experience using C Tech's EVS and Seequent’s Leapfrog Works for environmental applications, he has created more than 600 3D site models over his career. These 3D site models include soil and groundwater investigations and remediation projects in North America, South America, Europe, and Asia.

Contact us at aeg.nyp@gmail.com with questions or to get involved!