User guide for MODPATH Version 7—A particle-tracking model for MODFLOW

This report describes MODPATH, a particle-tracking model designed to work with output from the U.S. Geological Survey (USGS) groundwater flow model commonly referred to as MODFLOW.The performance of the program has been tested for a variety of test problems of simplified systems.Future applications might reveal errors that were not detected in the test simulations.Users should notify the USGS of any errors found in the report or the model program.Although the computer program has been written and used by the USGS, no warranty, expressed or implied, is made by the USGS or the U.S. Government as to the accuracy and functionality of the program and related program material.Nor shall the fact of distribution constitute any such warranty, and no responsibility is assumed by the USGS in connection therewith.