PUBLICATIONS -- release of report Documentation of computer programs

In Reply Refer To:                   Monday, November 6, 1989
WGS-Mail Stop 411


Subject:  PUBLICATIONS -- release of report "Documentation of
                          computer programs to compute and display
                          pathlines using results from the U.S.
                          Geological Survey modular three-
                          dimensional finite-difference ground-
                          water flow model" by David W. Pollock.

The attached report has recently been released as Open-File Report
89-381 pending publication in the Techniques of Water Resources
Investigations (TWRI) series.

The report describes and documents a particle tracking post-
processing package designed for use with the U.S. Geological
Survey modular finite-difference ground-water flow model. The
package consists of two computer programs: (1) MODPATH, which
computes particle coordinates along path lines, and (2) MODPATH-
PLOT, which graphically displays numerical results generated by
MODPATH. The particle tracking package is restricted to the
analysis of steady-state ground-water flow systems. Graphics
produced by MODPATH-PLOT are generated using the DISSPLA graphic
subroutine library that is available on WRD Prime computers.

This report should be made available to ground-water hydrologists
who currently use the modular finite-difference ground-water flow
model in their work, or who may be using it in the near future.
Copies of the computer programs can be obtained from the Software
Exchange System (SOFTEX), the WATSTORE Program Office, or the
author. Additional copies of Open-File Report 89-381 can be
obtained from the author.

                               Eugene P. Patten
                               Chief, Office of Ground Water


Distribution: A, B, S, FO, PO