Updates of the computer codes associated with: "Computer Model of Two-Dimensional Solute Transport and Dispersion in Ground Water"

                UNITED STATES DEPARTMENT OF THE INTERIOR
                           GEOLOGICAL SURVEY
                           RESTON, VA. 22092

In Reply Refer To:                           September 15, 1986
WGS-Mail Stop 411


OFFICE OF GROUND WATER TECHNICAL MEMORANDUM NO. 86.07

Subject:  GROUND WATER--Updates of the computer codes associated
                        with: "Computer Model of Two-Dimensional
                        Solute Transport and Dispersion in Ground
                        Water" by Leonard F. Konikow and John D.
                        Bredehoeft (1978): U.S. Geological Survey
                        (USGS) Techniques of Water-Resources
                        Investigations, Book 7, Chapter C2, and
                        "A Two- Constituent Solute-Transport Model
                        for Ground Water Having Variable Density"
                        by Ward E. Sanford and Leonard F. Konikow
                        (1985): USGS Water-Resources  Investigat-
                        ions Report 85-4279

Attached is an "update note" by Leonard F. Konikow and Ward E.
Sanford for the basic solute-transport model (1978 report) that
documents changes made and tested since the previous updates noted
in Ground Water Technical Memorandum No. 86.02, dated March 4,
1986.  The note, dated July 2, 1986, reports code changes "made
primarily to yield more efficient and more accurate calculations
of particle velocities, particularly in the vicinity of
permeability contrasts."

Two "update notes" by Ward E. Sanford and Leonard F. Konikow that
document changes made and tested since the release of the variable
density version of the solute transport model (1985) made by
Ground Water Technical Memorandum No. 86.03, dated March 5, 1986,
are also attached.  The note, dated July 3, 1986, reports changes
"made primarily to correct the mass-balance calculations and
output, and to yield more efficient and more accurate calculation
of particle velocities, particularly in the vicinity of
permeability contrasts."  The note, dated July 9, 1986, reports
changes that will "allow a direct solver with D4 ORDERING to be
used in place of the SIP solver in the original version of the
code."

The computer code for the basic solute transport model (1978
report) is available on the Headquarters PRIME computer QVARSB
through SOFTEX (ID=VAMWM00007) and has been modified to reflect
the July 2, 1986, update.  The updated computer codes (one version
uses the SIP solver and another version uses a direct solver with
D4 ORDERING) for the variable density code (1985 report) are also
available through SOFTEX (SYSTEM ID=VATCW00010).

This memorandum is intended to keep you informed of the model
updates and improvements as they become available.



                                   (s) Charles A. Appel
                                   for Eugene P. Patten
                                   Chief, Office of Ground Water

Attachments

WRD Distribution:  A, B, S, FO, PO