READ.ME FILE
============

Date : 04/20/98
Description : AIR3D software package for personal computer

Accompanying report: Documentation of AIR3D, An Adaptation of the
Ground-Water-Flow Code MODFLOW to Simulate Three-Dimensional Air
Flow in the Unsaturated Zone, by C.J. Joss and A.L. Baehr, 1995,
U.S. Geological Survey Open-File Report 94-533, 154 p. 


The files contained in this directory comprise the AIR3D software
package for application on a personal computer. The files are as
follows:

PREAIR.FOR -- preprocessor Fortran source code;

POSTAIR.FOR -- postprocessor Fortran source code;

MODBAS.FOR, MODBCF.FOR, MODFLOW.FOR, MODSIP.FOR, MODSOR.FOR,
MODUTL.FOR, MODDRN.FOR, MODEVT.FOR, MODGHB.FOR, MODRCH.FOR, 
MODRIV.FOR, AND MODWEL.FOR-- Fortran source codes for the MODFLOW package;

INFILE4.PRE, DATAIR4.PRE, and INFILE4.POS -- example input files
described in Sections 3.3.3, 3.3.4, and 4.5.3 of the accompanying
documentation.

It is assumed that users have access to a Fortran compiler. 

Installation and execution procedure will depend on your
computing system, however a general procedure is outlined as
follows:

1. Copy files from diskette into a directory created for 
AIR3D on your computer.

2. Check default settings. If your Fortran compiler 
requires an extension for Fortran code files other than 
.FOR then rename the files accordingly. You may need to 
change the input and output unit number settings in 
PREAIR.FOR, POSTAIR.FOR, and MODFLOW.FOR for 
compatibility with your computer. The sections of code 
defining these units are clearly identified in the source 
codes and are identified in the documentation in Section 
3.2.1 for PREAIR.FOR and Section 4.2.1 for POSTAIR.FOR.

3. Compile and load the source codes. This procedure will 
depend on your compiler. The MODFLOW files typically are 
compiled and loaded together. Note that PREAIR.FOR,
the MODFLOW files and POSTAIR.FOR should all be compiled 
using the same Fortran compiler to maintain compatibility 
during data transfer between the programs.

4. Create three input files to define you simulation. The 
two input files for the preprocessor program PREAIR may 
be created by running PREAIR and accessing the menu. 
Example files INFILE4.PRE, DATAIR4.PRE are provided. The 
third input file is for the postprocessor program 
POSTAIR, it may be created by running POSTAIR and 
accessing the menu. Detailed definitions of the input 
files are provided in the documentation.

5. Execute the programs PREAIR, MODFLOW, and POSTAIR in 
series. On personal computers, AIR3D runs in a DOS 
environment (it is not a Windows program).
The sequence of DOS commands are as follows:

PREAIR

MODFLOW < INFILE.MOD

POSTAIR

Note that the file INFILE.MOD is created by PREAIR and 
contains the names of the MODFLOW input files.


Questions and copies of the documentation should be temporarily directed to either:

Arthur L. Baehr
U.S. Geological Survey
810 Bear Tavern Road
West Trenton, New Jersey 08628
609-771-3900

Permanent archival will be done by:

U.S. Geological Survey
Earth Science Information Center
Open-File Reports Section
Box 25286, MS 517
Denver Federal Center
Denver, Co. 80225