Computer program for ground-water systems: "Documentation of finite-difference model for simulation of three-dimensional ground-water flow,"


               UNITED STATES DEPARTMENT OF THE INTERIOR
                           GEOLOGICAL SURVEY
                        RESTON, VIRGINIA  22092

                                                       GW Branch

                                                November 7, 1975
                                                       4351 5016

GROUND WATER BRANCH TECHNICAL MEMORANDUM NO. 76.05

Subject:  GROUND WATER - Computer program for ground-water
                         systems: "Documentation of finite-
                         difference model for simulation of
                         three-dimensional ground-water flow,"
                         by Peter C. Trescott.

The attached open-filed report by Peter Trescott, presently
available only in limited quantity, provides documentation for a
computer program that extends our simulation capability of ground-
water systems, from two specialists concerned with aquifer
modeling studies.  Because some aquifer systems can not be
represented adequately by two-dimensional approximations, this
program overcomes one of the important limitations associated with
two-dimensional models.

Trescott's program permits consideration of an aquifer system that
is heterogeneous, anisotropic, and irregularly bounded.  Stresses
on the system may be in the form of well discharge, well recharge,
and recharge from precipitation.  The program can be used to
simulate three-dimensional aquifer systems, and can simulate
efficiently quasi-three-dimensional systems consisting of two-
dimensional aquifers separated by intervening confining layers.
The upper aquifer can occur under water-table conditions and the
model can handle multiple pumping periods.

Requests for additional copies of this documentation or for copies
of the card deck should be directed to:

               Mr. Ralph N. Eicher, Chief
               Office of Teleprocessing, MS 805
               U.S. Geological Survey
               Reston, Virginia  22092

This report, and an updated version of Trescott's 2-D aquifer
model, are being readied for publication as TWRI's.



                              (s) Charles A. Appel
                              for Chief, Ground Water Branch
                              Water Resources Division

Enclosure

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