MODFLOW-2000 and MODPATH4 used to simulate groundwater flow and contaminant transport in the Pohatcong Valley, Warren County, New Jersey

The U. S. Geological Survey, in cooperation with the U.S. Environmental Protection Agency, developed a numerical groundwater flow model, using MODFLOW2000, to simulate groundwater flow in the Pohatcong Valley including the area within the Pohatcong Valley Ground Water Contamination Site. In 1978, the chlorinated solvents trichloroethene (TCE) and tetrachloroethene (PCE) were detected in the Pohatcong Valley in production wells in Washington Borough and Washington Township, Warren County, New Jersey. Subsequent investigation revealed that many domestic wells in Washington and Franklin Townships also were contaminated, and in 1989 the Pohatcong Valley Ground Water Contamination Site was added to the U.S. Environmental Protection Agency (USEPA) National Priority List. A remedial investigation, by the USEPA and CH2M Hill with technical assistance from the U.S. Geological Survey (USGS), was begun in 1999. The simulation of groundwater flow in the Pohatcong Valley described here was conducted by the USGS in cooperation with the USEPA. The groundwater flow model, using MODFLOW2000 and the particle tracking program MODPATH, estimated flow paths of groundwater from known sources of contamination in Washington Borough and tested possible site contamination remediation alternatives. Five groundwater remediation alternatives (GW2a, GW2b, GW3a, GW3b, and GW4b) were simulated. In addition, a 10 year solute transport simulation was conducted, using the USGS groundwater transport process, to illustrate the potential for dispersion to increase the width of the solute plume. 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/sir20065269).