MODFLOW-2005, MODPATH, and MOC3D used for groundwater flow simulation, pathlines analysis, and solute transport in the crystalline-rock aquifer in the vicinity of the Savage Municipal Water-Supply Well Superfund Site, Milford, New Hampshire

The U.S. Geological Survey, in cooperation with the U.S. Environmental Protection Agency and the New Hampshire Department of Environmental Services, developed a model for used with MODFLOW-2005 and MODPATH5 to evaluate groundwater flow and advective transport under pre- and post-remediation conditions in the crystalline-rock aquifer in the vicinity of the Savage Municipal Water-Supply Well Superfund site Milford, New Hampshire. In addition, a previously developed model (https://doi.org/10.3133/sir20045176 and https://doi.org/10.3133/ofr20121079) was used with MOC3D to evaluate the solute-transport of tetrachloroethylene (PCE). In 2010 PCE, a chlorinated volatile organic compound, was detected in groundwater from monitoring wells tapping the deep (more than 300 feet below land surface) fractures in a crystalline-rock aquifer. The crystalline-rock aquifer underlies the Milford-Souhegan glacial-drift (MSGD) aquifer (a high water-producing aquifer) and the Savage Municipal Water-Supply Well Superfund site. Residential water-supply wells are within one-quarter of a mile of the PCE-contaminated monitoring wells and many are likely installed in similar rock types and formations as those of the monitoring wells. The need to understand and quantify flow and transport in the crystalline- rock aquifer is crucial in assessing strategies for remediation. The current, area-wide model simulates flow in the crystalline-rock aquifer and covers a much larger area than previous models with the goal of improving the computation of groundwater flow from distal locations to the residential wells and the area. This USGS data release contains all of the input and output files for the simulations described in the associated model documentation report (https://doi.org/10.3133/sir20205137).