Candace Ann Beauvais, P.G.

Case Studies in Surface Runoff and Fate-and-Transport Modeling at AFFF-Impacted Sites

Candace Ann Beauvais, P.G., Senior Hydrogeologist and Project Manager, Tetra Tech

Per- and polyfluoroalkyl substances (PFAS) are a key component of aqueous film-forming foams (AFFF) used to suppress fuel-related fires. PFAS partition at air–water interfaces, a property that contributes to firefighting performance while also influencing their environmental fate and transport. Extensive historical use of AFFF at fire-training facilities, civilian and military airports, and chemical manufacturing sites has resulted in PFAS impacts to multiple environmental media. Because PFAS behavior and movement are highly complex, thorough site investigations are required to develop a conceptual site model that effectively characterizes contaminant migration pathways and transport mechanisms. This presentation will describe how surface runoff modeling can be used to evaluate PFAS fate and transport and to guide targeted soil and groundwater sampling during field investigations. Case examples will also be presented from sites where integrated modeling approaches combining surface runoff with fate-and-transport analyses were used to refine conceptual site models and improve understanding of PFAS migration pathways.

Ms. Candace Beauvais is a hydrogeologist and geologist with 27 years of experience specializing in groundwater flow modeling and contaminant fate and transport, including emerging contaminants such as PFAS. She has led and managed dozens of complex soil and groundwater investigations under state and federal regulatory programs, developing conceptual site models to characterize contaminant sources, migration pathways, and transport mechanisms. Her work includes designing and directing targeted sampling programs and monitoring networks, interpreting geologic and hydrogeologic data, and applying integrated modeling approaches to support investigation and remedial decision-making. Ms. Beauvais also brings strong expertise in GIS and environmental data management, integrating chemical, hydrologic, and geotechnical datasets to support spatial analysis and numerical simulation. Her project experience spans a broad range of contaminants, with recent work focused on applying surface runoff, fate-and-transport, and field investigation strategies to improve understanding of PFAS migration at AFFF-impacted sites.