Groundwater Flow and Transport Models for a Manufacturing Site
HydroAnalysis developed groundwater flow and transport models to assist in planning future remedial actions for tetrachloroethylene contamination in groundwater at a former industrial manufacturing site in Massachusetts. The public domain MODFLOW, MODPATH, and MT3D computer codes were used to predict, respectively, groundwater flow, groundwater flow trajectories, and contaminant transport. The groundwater flow model represented long-term annual-average hydrology and was bounded by natural hydrologic features to delineate a physically consistent model area. Parameters used in the flow model were derived from site-specific data, regional geologic and hydrologic information, and information from the technical literature. The model was calibrated with only limited alteration of the parameter values so as to achieve acceptable agreement with long-term average groundwater levels measured in on-site monitoring wells.
The mass transport model was based on accepted parameter values from the literature and regulatory guidance and achieved reasonable agreement between the model predictions and field measurements of tetrachloroethylene. The two models were used to compare a variety of alternative remedial actions at the site including DNAPL removal, soil cleanup, and pump-and-treat cleanup of the groundwater plume. The project was completed for the private owner in cooperation with Tetra Tech.