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).