A realistic analysis of the migration and fate of contaminants in the subsurface is the cornerstone of our risk-based approach to site evaluation and remediation. Personnel from THWA have analyzed the fate and transport of contaminants at hundreds of sites across the country. Our vast experience in this area is invaluable because we have changed the way the fate and transport of contaminants is evaluated. Our innovations in this have saved responsible parties millions of dollars. Todd Wiedemeier led the way in developing methods to evaluate natural attenuation. He is the senior author of the Air Force Center for Environmental Excellence document.
Actualization Modeling
Visualization models allow project managers to easily communicate the known current conditions of a site. By portraying this complex data completely in a visual format, regulatory negotiations may quickly proceed to other relevant issues. Less regulatory involvement equals cost savings for the client.
Personnel from THWA have forensically evaluated and correlated environmental data for highly complex subsurface conditions at a wide variety of sites. For example, at a Los Angeles area refinery a THWA associate compiled, organized and correlated over 10 years of lithologic and hydrogeologic data from over 220 monitoring wells and borings. The data at this site represented three distinct hydrologic regimes, separated by distinct identifiable unsaturated zones. Prior to completion of the visualization model a conceptual site model was developed to aid client understanding regarding the unique complexities associated with this site and provided a basis for correlative efforts.
At a former central California natural gas processing plant the same associate assessed the property and developed a visualization model portraying time series visualizations of potentiometric surface relative to lithologic units and the identified extent of vadose zone contaminate extent. The visualization snapshot to the right visually depicts actual site environmental condition and simultaneously examines a regulatory mandated excavation remedial option.
Predictive Modeling
Personnel from THWA changed the way the fate and transport of contaminants are evaluated through their involvement in the development and review of the Bioplume III, Bioscreen, and Biochlor models for evaluating natural attenuation. Depending on the type of contamination present at a given site, these models can be very useful for predicting the future behavior of plumes of organic chemicals dissolved in groundwater.
Bioplume II@ modeling in support of the natural attenuation alternative for ground water contaminant plumes at six Air Force bases across the country. The scope of work for this project includes review of existing site data, development of conceptual site models, collection of additional model-specific site characterization data, contaminant fate and transport modeling using Bioplume II@, preparation of a report detailing model results and recommendations, and technical support during regulatory negotiations.