"Status of ground-water modeling in the U.S. Geological Survey,"


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

                                                      GW Branch

                                                August 27, 1976
                                                 Code 4351 5016

GROUND WATER BRANCH TECHNICAL MEMORANDUM NO. 76.11-T

Subject:  PUBLICATIONS - Report:  "Status of ground-water modeling
                         in the U.S. Geological Survey," by
                         Charles A. Appel and John D. Bredehoeft,
                         U. S. Geological Survey Circular 737.

The enclosed report summarizes USGS developments in the use of
models for the analysis of ground-water problems.  Some general
types of problems for which models have been, or are being
developed include: (1) ground-water flow in saturated or
partially-saturated materials, (2) land subsidence resulting from
ground-water extraction, (3) flow in coupled stream-aquifer
systems, (4) coupling of rainfall-runoff basin models with soil
moisture accounting and aquifer flow models, (5) interaction of
economic and hydrologic considerations, (6) predicting the
transport of contaminants in an aquifer, and (7) estimating the
effects of development alternatives for geothermal systems.  The
status of modeling activity for various models is reported as
being in a developmental, verification, operational, or continued-
improvement phase.  References that provide useful details on the
characteristics of the models are identified.

We recognize that we may have overlooked some of the modeling
development of ongoing district programs by limiting references to
cases where documentation presently is available or definitely
planned for completion in the very near future.  Please bring to
our attention any modeling activities that should have been, but
were not, acknowledged.



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

Enclosure

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