June 9, 1997

                         SAC - Version 97-01 1997/05/01
                         Slope-Area Computation Program


For assistance, enhancement requests, or bug reports contact the Hydrologic
Analysis Software Support Team via email at h2osoft@usgs.gov.  See the file
doc\sac.txt for descriptions, references, and additional contacts for
this software.  Instructions for installation, execution, and testing are
provided below.

This version of SAC is packaged for use on personal computers using
the DOS operating system.  The installation procedures and the compiled
version of SAC must be run using either DOS directly or a DOS window
within Microsoft Windows, Windows 95, or Windows NT.


                            TABLE OF CONTENTS

                         A. DISTRIBUTION PACKAGES
                         B. EXTRACTING FILES
                         C. INSTALLING
                         D. RUNNING THE SOFTWARE
                         E. TESTING


A. DISTRIBUTION PACKAGES

SAC is distributed as a package that contains the software (sac), data
sets, and information files.  The software is available as compiled code
only.

The following self-extracting DOS distribution files is currently available:

         sac9701b.exe - Compiled using Lahey Fortran 90

Included in directory sac97.01/doc is a Portable Document Format (PDF)
version of the SAC documentation (sacman.pdf).  A PostScript version of this 
report is available from:
      http://water.usgs.gov/software/sac.html

The PDF file is readable and printable on various computer platforms using
Acrobat Reader from Adobe.  The Acrobat Reader is freely available from
the following World Wide Web sites:
      http://www.adobe.com/
      http://www.shareware.com/

and by File Transfer Protocol (FTP) from the following site:
      ftp.adobe.com (path: /pub/adobe/acrobat)


B. EXTRACTING FILES

The directory sac97.01 is created (or overwritten) when the files are 
extracted.  If the sac97.01 directory already exists, you may want to 
delete or rename it before extracting the files.  The following are the 
steps to extract the files from a distribution file.  Note, replace 
<disk drive> with the drive letter where you want to install SAC and 
optionally replace [directory] with the name of a directory on that drive:

   1. If you are not in the directory where the distribution file is
      located, go there.  For example (if already on the C disk drive):

         cd c:\wrdapp

   2. Extract the files using the command: 

        sac9701b -d -o <disk drive>:\[directory] 

      Note, be sure to include the -d (restore directory structure) and 
      -o (overwrite existing files) options and ":\" in the command.  
      Examples are:

         sac9701b -d -o c:\

         sac9701b -d -o c:\wrdapp

The following directory structure will be created (the contents of each
directory are shown to the right):

      sac97.01          ; copy of this readme file
        `-----bin       ; compiled executable and Lahey error file
        `-----doc       ; documentation files
        `-----src       ; makefile
        `-----test      ; batch files to run verification tests
        `-----data      ; standard data sets used in verification tests

Notes:
a) It is recommended that no user files are kept in the sac97.01
   directory structure.  If you do plan to put files in the sac97.01
   directory structure, do so only by creating subdirectories of
   sac97.01.
b) Brackets "[xxx]" are used to indicate optional arguments to commands.


C: INSTALLING

To make the SAC program accessible from any directory, the directory
containing the executable should be included in the PATH environment
variable.  For example, you could add a line similar to the following
to the AUTOEXEC.BAT file:

  PATH=%PATH%;C:\sac97.01\bin

Note, substitute the appropriate drive letter and pathname if not C:\
as shown above.

As an alternative, the SAC executable can be installed in a directory
already included in the PATH environment variable.  The makefile (input
instructions to the Lahey make program--located in sac97.01\src) contains
instructions to optionally place a copy of the executable contained in
sac97.01\bin in a specified directory.  Use the following two commands to
do this:

       cd sac_source_directory
       make install BINDIR=directory_for_executable

For example:

       cd C:\sac97.01\src
       make install BINDIR=C:\wrdapp\bin

Note, the makefile may need to be modified to be used with make programs
other than the Lahey make program.


D. RUNNING THE SOFTWARE

        **System Requirements**
        - 386-based or higher personal computer with math co-processor
        - 2 MB application RAM
        - 2 MB hard disk space

SAC has been compiled using the Lahey Fortran 90 extended memory
compiler version 3.00f.  The file "LF90.EER" (from the Lahey compiler)
located in sac97.01\bin contains error messages.  If an error occurs,
this file is used to print error messages if the sac97.01\bin directory
is included in the PATH environment variable; if LF90.ERR cannot be found,
the error will only be identified by number.

After SAC is properly installed in a directory that is included in
your PATH, the program is initiated using the command:  sac.
SAC prompts for type of program input (currently only supports WSPRO
formatted data), input file name, output file name, and then run title.


E. TESTING

Test data sets are provided to verify that the program is correctly
installed and running on the system.  The tests may also be looked at
as examples of how to use the program.  The directory sac97.01\test
contains batch files to run the tests.  The directory sac97.01\data
contains the input data and expected results for each test.  Run the
tests in the sac97.01\test directory using the command:

   test

After the tests are completed, the results can be compared to the
expected results.  To clean-up after the tests, type the command:

   clean

The tests are described in the table below.  Test is the test number,
program is the program used to run the test, and the usage column
indicates how a file is used, with i for input, o for output, and
i/o for both input and output.

test  program  description of test and files      file name & usage
----  -------  ---------------------------------  -----------------
  1   sac      Slope-area reach example with
               level-water surface in cross
               sections

               SAC input data                     example1.dat   i
               Program output                     example1.out   o

  2   sac      Slope-area reach: Snake Creek
               near Connell, Wash., for flood 
               of February 21, 1956

               SAC input data                     example2.dat   i
               Program output                     example2.out   o

  3   sac      Sloping water surface with 
               conveyance weighting

               SAC input data                     example3.dat   i
               Program output                     example3.out   o

  4   sac      Slope-area reach example with
               level-water surface in cross
               sections, metric output

               SAC input data                     example4.dat   i
               Program output                     example4.out   o

  5   sac      Simple reach example with
               metric input and feet-second output

               SAC input data                     example5.dat   i
               Program output                     example5.out   o


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                             Good Luck!

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