GROUND WATER -- Release of Open-File Report 91-536, A Method of Converting No-Flow Cells to Variable-Head Cells 


In Reply Refer To:                           February 21, 1992
Mail Stop 411


OFFICE OF GROUND WATER TECHNICAL MEMORANDUM NO. 92.04

Subject:  GROUND WATER -- Release of Open-File Report 91-536,
         "A Method of Converting No-Flow Cells to Variable-Head Cells for the
         U.S. Geological Survey Modular Finite-Difference Ground-Water Flow
         Model," by M.G. McDonald, A.W. Harbaugh, B.R. Orr, and D.J. Ackerman

The subject report describes an addition to the U.S. Geological Survey modular
model, MODFLOW, which allows dry (no flow) model cells to convert to wet
(variable head).  This new capability will be useful for simulating a rising
water table that crosses into previously dry cells.  Typical examples are the
recovery of water levels after pumping has stopped and rising water levels
caused by artificial recharge.  The report describes how to add the new
capability to MODFLOW and how to use it.

The program code can be retrieved from the QVARSA Prime computer.  Two files
are in directory MODFLOW:

     BCF2.F77 -- source code for the new MODFLOW package
     BCF2.CALL -- Call statements for the Main MODFLOW program

To retrieve these files, issue the following commands from any of our Prime
computers:

     FTR MODFLOW>BCF2.F77 FTS_DEPOT>== -SS QVARSA
     FTR MODFLOW>BCF2.CALL FTS_DEPOT>== -SS QVARSA

We recommend that this report be brought to the attention of technical and
management personnel concerned with ground-water modeling studies.  Additional
copies of the report are available from the Office of Ground Water.



                                      Joseph S. Rosenshein
                                      Acting Chief, Office of
                                      Ground Water

Distribution:  A and B (memo only)
     S, FO, and PO (memo and report)