MODPATH Model Used to Evaluate Flowpaths from Two Contaminant Plume Source Areas near Joint Base Cape Cod, Western Cape Cod, Massachusetts

The U.S. Geological Survey (USGS) used an existing groundwater flow model to determine steady-state groundwater flowpaths from two contaminant plume source areas by using a particle tracking post-processing model (MODPATH; Pollock, 2012) as part of an assessment of potential contaminant discharge at the coast in Bourne, Massachusetts. The extents of the source areas, originating from two separate tanker-truck rollovers, were determined and documented by the Air Force Civil Engineer Center (AFCEC, 2025). The existing groundwater model is a steady-state, three-dimensional MODFLOW-2005 model of the Sagamore flow lens of the Cape Cod aquifer documented by Walter and others (2019). This USGS data release contains the input and output files for the MODPATH simulations described in the associated journal manuscript (https://doi.org/gwat.70063).