point3_mod(1)    U.S. Geological Survey (wrdapp)    point3_mod(1)


NAME
       point3_mod - An analytical solution for three-dimensional ground-
                    water solute transport in an infinite system with
                    uniform flow and a continuous point solute source.
                    POINT3_MOD is a specific modification of POINT3 to
                    duplicate the sample problem as shown in the
                    documentation.  This program uses superposition to
                    represent the example problem of three wells with a
                    discrete injection period of 400 days.

ABSTRACT
       This program is a modification of the POINT3 program that computes
       the analytical solution to the three-dimensional solute-transport
       equation for an infinite system with a continuous point solute
       source.

METHOD
       The computer program calculates the concentration for the example
       three-dimensional system based on the equation given in Wexler
       (1992a, p.  49). The concentration is calculated for a injection
       period of 400 days and three injection wells as specified in the
       documentation.

HISTORY
       Version 1.1 1996/04/03 - Code restructuring and clean up: use of
          consistent spacing; use of upper and lower case variable names;
          statement labels renumbered; comment statements altered to be
          consistent; use of Hollerinth data in FORMAT statements removed;
          all variables and routines declared; duplicate code placed in new
          routines; interactive prompting for graphics output devices
          added.  Bug fixed in contour routine related to contours at the
          left edge of the plot.

       Version 1.0 1990/04/03 - Initial published version.

DATA REQUIREMENTS
       The program requires data on advective velocity, dispersion
       coefficient, spatial information, temporal information, and boundary
       concentrations.  Optional data may include a first-order solute-
       decay coefficient.

OUTPUT OPTIONS
       Output is the calculated concentrations at specified points in time
       and space. A plotting option exists to view the output as graphs.

SYSTEM REQUIREMENTS
       pgm_name is written in Fortran 77 with the following extensions:
       use of include files and reference to compiler-dependent system date
       and time routines.  Graphics are coded using Computer Associates'
       DISSPLA library references.  Generally, the program is easily
       installed on most computer systems that have access to the DISSPLA
       graphics library.  Alternatively, graphics can be disabled and data
       can be easily extracted from the program output and plotted using
       graphic presentation programs.  The code has been used on UNIX-based



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point3_mod(1)    U.S. Geological Survey (wrdapp)    point3_mod(1)


       computers.

DOCUMENTATION
       Wexler, E.J., 1992a, Analytical solutions for one-, two-, and three-
          dimensional solute transport in ground-water systems with uniform
          flow: U.S. Geological Survey Techniques of Water-Resources
          Investigations, book 3, chap. B7, 190 p.

       Wexler, E.J., 1992b, Analytical solutions for one-, two-, and three-
          dimensional solute transport in ground-water systems with uniform
          flow -- Supplemental Report: Source codes for computer programs
          and sample data sets: U.S. Geological Survey Open-File Report
          92-78, 3 p., 1 computer diskette.

TRAINING
       Some of the programs are introduced in the class Ground-Water
       Solute-Transport Concepts for Field Investigations (GW2005TC),
       offered annually at the USGS National Training Center.

CONTACTS
       Operation:
          U.S. Geological Survey
          Office of Ground Water
          Thomas E. Reilly
          411 National Center
          Reston, VA 20192

          tereilly@usgs.gov

       Distribution:
          U.S. Geological Survey
          Hydrologic Analysis Software Support Program
          437 National Center
          Reston, VA 20192

          h2osoft@usgs.gov

       Official versions of U.S. Geological Survey water-resources analysis
       software are available for electronic retrieval via the World Wide
       Web (WWW) at:

                  http://water.usgs.gov/software/

       and via anonymous File Transfer Protocol (FTP) from:

                  water.usgs.gov (path: /pub/software).

       The WWW page and anonymous FTP directory from which the ANALGWST
       software can be retrieved are, respectively:

                  http://water.usgs.gov/software/analgwst.html
                                --and--
                  /pub/software/ground_water/analgwst




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