This archive contains the source code, compiled (executable) program, and an
example problem for the computer program described in the following USGS report:

O'Reilly, A.M., 2004, A method for simulating transient ground-water recharge
     in deep water-table settings in central Florida by using a simple
     water-balance/transfer-function model: U.S. Geological Survey Scientific
     Investigations Report 2004-5195, 49 p.

This report presents a computer program for simulating transient ground-water
recharge in deep water-table settings. The performance of this computer program
has been compared to models of hypothetical variably saturated flow systems;
however, future applications of the programs could reveal errors that were not
detected in the test simulations. Users are requested to notify the USGS if
errors are found in the report or in the computer program. Correspondence
regarding the report or program should be sent to:

U.S. Geological Survey
224 West Central Parkway, Suite 1006
Altamonte Springs, Florida 32714

Although this program has been used by the USGS, no warranty, expressed or
implied, is made by the USGS or the United States Government as to the accuracy
and functioning of the program and related program material. Nor shall the fact
of distribution constitute any such warranty, and no responsibility is assumed
by the USGS in connection therewith.

The computer program documented in this report is available from the USGS at
the following World Wide Web address:

http://pubs.water.usgs.gov/sir2004-5195/

NOTE: Use of trade, product, or firm names is for descriptive purposes 
      only and does not imply endorsement by the U.S. Geological Survey.


ARCHIVE HISTORY:
*******************************************************************************

   DATE           PERSON                          ACTION
==========   ==================   =============================================
02/28/2005   Andrew M. O'Reilly   originally created; WBTF v1.0 (first public
                                  version); wbtf.exe was compiled for MS-DOS
                                  with Compaq Visual Fortran Professional
                                  Edition 6.6.a and Windows XP Professional
                                  Version 2002 Service Pack 1 


CONTENTS OF ARCHIVE:
*******************************************************************************

                                  BYTES     DATE       FILE NAME
                                  ===== ============ =============
This file --                       3324 Feb 28 15:14 README.txt

'example' directory:
Effective Infiltration File --    40213 Feb 28 15:00 ei.csv
Evapotranspiration File --        13299 Jan 23  2004 et.txt
Gamma PDF file --                 31051 Feb 28 15:00 gam.csv
Precipitation File --             13961 Jan 22  2004 precip.txt
Average Recharge File --          37299 Feb 28 15:00 rch_avg.csv
Instantaneous Recharge File --   270164 Feb 28 15:00 rch_inst.csv
Main Input File --                  208 May 28  2004 wbtf.in

'exe' directory:
Executable file --               323584 Feb 28 14:27 wbtf.exe

'source' directory:
Fortran 90 code to calculate Gamma Function --      1535 Feb 28 14:26 gammln.for
Fortran 90 code for Transfer Function Module --    25545 Feb 28 14:25 trfn.for
Fortran 90 code for Water Balance Module --         5576 Feb 28 14:24 wbal.for
Fortran 90 code for WBTF MAIN program --            6535 Feb 28 13:42 wbtf.for
     

DIRECTIONS FOR RUNNING COMPUTER PROGRAM:
*******************************************************************************

1) Open a DOS window in the 'example' directory
   NOTE:  Program can be run from any directory by typing the appropriate path
          or by modifying your PATH variable to include the path to where
          wbtf.exe is stored.
2) Type ..\exe\wbtf
   NOTE:  The executable file 'wbtf.exe' was compiled for use on computers
          running the Microsoft Windows or DOS operating system.  For other
          operating systems, the code will have to be compiled on your computer
          platform.  The code is written in standard Fortran 90.
3) At the prompt, enter the name of the Main Input File: 'wbtf.in'
4) Program will run without further user interaction.  The Main Output File
   will be written to the screen.
   NOTE:  The Gamma PDF file (gam.csv) contains a listing of the Gamma PDF and
          Gamma CDF (cumulative density function) for each value of tau up to
          the memory of the Gamma PDF (Gamma CDF = 0.99).  For a small value of
          delta-tau or a large memory, the size of the file can get very large,
          in which case it will NOT be written.