This is a model of two superpositioned parallelipiped
initial source volumes with nonequilibrium sorption. The source
areas retain significant nonequilibrium mass, and are visible at
the left side of the plume. This is a plot of concentration on
the plane z=0, which cuts through the initial source
volumes.
SOLUTRANS Capabilities
The
solutions in SOLUTRANS all assume a uniform onedimensional flow
field in the positive x direction. There is threedimensional
dispersion with different coefficients allowed in all three
directions. One set of solutions assumes equilibrium in the solute
and adsorbed phases (Leij et. al., 1991), while another set of
solutions allows nonequilibrium (kinetic) conditions (Leij et. al.,
1993).
With the nonequilibrium solutions, the solute may be out of
equilibrium with some of the adsorption sites. Van Genuchten and
Wagenet (1989) and Leij et. al. (1993) describe two common ways of
conceptualizing nonequilibrium transport; a ``twosite'' concept and
a ``tworegion'' concept. Both concepts lead to similar partial
differential equations that are, in fact, written as a common
dimensionless partial differential equation. In the twosite
concept, some fraction of adsorption sites are at equilibrium while
other sites are not. At the nonequilibrium (kinetic) sites, a
firstorder rate law governs adsorption. In the tworegion concept,
there is mobile pore water and immobile pore water and both are in
equilibrium with the sorption sites that they are in contact with.
Solute migrates by advection and dispersion in the mobile region,
and firstorder diffusion transfers solute mass from the mobile
region to the immobile region (Coats and Smith, 1964; van Genuchten
and Wierenga, 1976).
Separate firstorder decay coefficients may be specified for the
equilibrium and the nonequilibrium phases. The nonequilibrium models
allow you to examine the distribution of equilibrium (mobile water)
concentrations, nonequilibrium (immobile water) concentrations, and
the total (aqueous + adsorbed) concentration.
Unlike the solutions of Domenico and Robbins (1985, Groundwater,
v. 23, p. 476.) and Domenico (1987, Jour. Hydrol. v. 91, p. 49),
these solutions do not make approximations that cause errors near
the source. These are exact solutions which involve some numerical
integration.
Both the equilibrium and nonequilibrium solutions allow four
different source geometries:
 rectangular inlet area
 circular inlet area
 parallelipiped (rectangular box) initial volume
 cylindrical initial volume
The ten solutions implemented in SOLUTRANS are listed below:
 Rectangular inleat, equilibrium, steadystate
 Rectangular inlet, equilibrium
 Rectangular inlet, nonequilibrium
 Circular inlet, equilibrium, steadystate
 Circular inlet, equilibrium
 Circular inlet, nonequilibrium
 Parallelepiped initial volume, equilibrium
 Parallelepiped initial volume, nonequilibrium
 Cylinder initial volume, equilibrium
 Cylinder initial volume, nonequilibrium
Using the superposition features
built into SOLUTRANS, it is possible to model contaminant sources
that have irregular distributions in time and space as shown
here . See the figure
above for an example of source superposition.
All these solutions may be used to create simpler
twodimensional, onedimensional, and diffusiononly solutions, if
needed.
SOLUTRANS User Interface
SOLUTRANS
has a seamless, Windowsstandard user interface. It has been
designed to be very simple and fast. Most common modeling operations
are executed at the push of a button on the
main screen. Mathematical model input data are accessed directly in a
spreadsheetlike grid. Data can be imported and exported using the Windows
Clipboard.
SOLUTRANS can produce three types of plots: 1) concentrations vs.
distance along a line, 2) concentrations vs. time at a point, and 3)
surface plots of concentrations vs. location on a plane. Press here
to see examples of plot types (1) and (2), and see the above plot
for an example of type (3).
Plots are made on the screen, and may be exported to the Windows
Clipboard or to disk files in either bitmap (.BMP) or metafile
(.WMF) format. Concentration data may also be exported directly in
commadelimited ASCII files for use with other visualization
software programs. Data may also be exported in .GRD format files
for surface plotting using SURFER software.
The following forms of online help are available: tips that
automatically display when you pause over a control,
contextsensitive help (F1 key), and a Windowsstandard help file.
The help file is indexed, searchable, printable, and it contains
embedded jumps to related topics.
SOLUTRANS Documentation
Most of
the information about how to use the software is in the online help
system. The SOLUTRANS Manual is a 7 x 9 inch spiral bound booklet
containing the following sections.
 Introduction  describes the software and how to install
it.
 Tutorial  stepbystep development and modification of a
SOLUTRANS model, showing screens as they appear in the process.
 Method Employed  a detailed section describing the
governing equations and the general nature of the analytic
solutions employed.
 Modeling Tips  includes advice about parameter units,
computational speeds, superposition, 1D, 2D, and
diffusiondominated transport models, etc.
 Program Checks  42 separate checks of the solutions
implemented in SOLUTRANS. The model input files for the check
models are included on the software diskettes.
 References
SOLUTRANS System Requirements
 32bit Windows operating system (Windows 95/98/NT as of this
writing)
 4 MB of hard disk space
 8 MB of memory
Licenses and
Support
 The commercial SOLUTRANS license is a typical software
license; one license allows installation on one computer at a
time.
 The academic license is a site license available for qualified
educational institutions and is restricted to academic,
noncommercial purposes.
 Purchase of either license includes unlimited support to make
sure that SOLUTRANS operates properly on your system.
References
Coats, K.
H. and B. D. Smith. 1964. Deadend pore volume and dispersion in
porous media. Soc. Petrol. Engr. Jour., v. 4, p. 7384.
Leij, F. J., T. H. Skaggs, and M. Th. van Genuchten. 1991.
Analytical solutions for solute transport in threedimensional
semiinfinite porous media. Water Resources Research, v. 27(10), p.
27192733.
Leij, F. J., N. Toride, and M. Th. van Genuchten. 1993.
Analytical solutions for nonequilibrium solute transport in
threedimensional porous media. Journal of Hydrology, v. 151, p.
193228.
Leij, F. J. and S. A. Bradford. 1994. 3DADE: A computer program
for evaluating threedimensional equilibrium solute transport in
porous media. U. S. Salinity Laboratory Research Report No. 134,
Riverside, California.
Leij, F. J. and N. Toride. 1997. N3DADE: A computer program for
evaluating nonequilibrium threedimensional solute transport in
porous media. U. S. Salinity Laboratory Research Report No. 143,
Riverside, California.
van Genuchten, M. Th. and J. C. Parker. 1984. Boundary conditions
for displacement experiments through short laboratory soil columns.
Soil Science Soc. of Am. Jour., v. 48, p. 703708.
van Genuchten, M. Th. and R. J. Wagenet. 1989. Two site/two
region models for pesticide transport and degradation: theoretical
development and analytical solutions. Soil Science Soc. of Am.
Jour., v. 53, p. 13031310.
van Genuchten, M. Th. and P. J. Wierenga. 1976. Mass transfer
studies in sorbing porous media: 1. analytical solutions. Soil
Science Soc. of Am. Jour., v. 40, p.
473481.
