by David W. Pollock (Author)

This report describes MODPATH, a particle-tracking model designed to work with output from the U.S. Geological Survey groundwater flow model commonly referred to as MODFLOW. The model program can be obtained at http: //water.usgs.gov/software/ground_water.html/. The performance of the program has been tested for a variety of test problems; however, future applications might reveal errors that were not detected in the test simulations