February 28, 2003

Addition of the Diffusion Analogy Surface-Water Flow Model (DAFLOW)
                            to MODFLOW-2000

The addition of DAFLOW to MODFLOW-96 is documented in "Modifications to
the Diffusion Analogy Surface-Water Flow Model (DAFLOW) for Coupling to
the Modular Finite-Difference Ground-Water Flow Model (MODFLOW)" by
Harvey Jobson and Arlen Harbaugh, USGS Open-File Report (OFR) 99-217. 
DAFLOW has subsequently been added to MODFLOW-2000.

Few changes were required to add DAFLOW to MODFLOW-2000.  The user
input files are identical to those documented in OFR 99-217.  As before
three files must be specified in the MODFLOW Name File, but there is a
change in the file type for one of the files.  As in MODFLOW-96, file
type DAF indicates the generic DAFLOW input file, and file type DAFG
indicates the input file for MODFLOW-specific data.  The third file is
an output file, which is normally called bltm.flw.  This file is
specified using DATA for the file type (rather than DAFF), and the file
unit must be one greater than the file unit used for the DAFG file.

MODFLOW/DAFLOW Release information

Version 1.0, April 14, 2000 -- Initial release

Version 1.1, Dec. 26, 2002 -- Updated to fix error that occurred when branches
                              were numbered in upstream direction.

Version 1.2, Feb. 28, 2003 -- Added to MODFLOW-2000