STANMOD for Windows, Version: 2.xx, December 2003
Concentration movement
STANMOD (STudio of ANalytical MODels) is a public domain Windows-based computer software package for evaluating solute transport in porous media using analytical solutions of the convection-dispersion solute transport equation.
Authors:
J. Simunek, M.Th. van Genuchten, M. Sejna, N. Toride and F. J. Leij
References:
Šimůnek, J., M. Th. van Genuchten, M. Šejna, N. Toride, and F. J. Leij, The STANMOD computer software for evaluating solute transport in porous media using analytical solutions of convection-dispersion equation. Versions 1.0 and 2.0, IGWMC - TPS - 71, International Ground Water Modeling Center, Colorado School of Mines, Golden, Colorado, 32pp., 1999.
van Genuchten, M. Th., J. Šimůnek, F. L. Leij, N. Toride, and M. Šejna, STANMOD: Model use, calibration and validation, special issue Standard/Engineering Procedures for Model Calibration and Validation, Transactions of the ASABE, 5(4), 1353-1366, 2012.
The Program
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Support and Links
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Models for 1D-transport problems
- CXTFIT 2.0 [Toride et al., 1995]
- CFITM [van Genuchten,1980]
- CFITIM [van Genuchten, 1981]
- CHAIN [van Genuchten, 1985]
- SCREEN [Jury et al., 1983]
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Models for 2D and 3D-transport problems
- 3DADE [Leij and Bradford, 1994]
- N3DADE [Leij and Toride, 1997]
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CXTFIT
Main Window The software package includes a modified and updated version of the CXTFIT code of Toride et al.[1995] for estimating solute transport parameters using a nonlinear least-squares parameter optimization method. This code may be used to solve the inverse problem by fitting a variety of analytical solutions of theoretical transport models, based upon the one-dimensional advection-dispersion equation (ADE), to experimental results. The program may also be used to solve the direct or forward problem to determine concentrations as a function of time and/or position. Three different one-dimensional transport models are considered: (i) the conventional equilibrium ADE; (ii) the chemical and physical nonequilibrium ADEs; and (iii) a stochastic stream tube model based upon the local-scale equilibrium or nonequilibrium ADE.
CFITM
Project Manager STANMOD also comes with an updated version of the CFITM code of van Genuchten [1980] for analyzing observed column effluent data using analytical solutions of the one-dimensional equilibrium advective-dispersive transport equation. The code considers analytical solutions for both semi-finite and finite columns.
CFITIM
Results - Concentration Profiles STANMOD also contains an updated version of the CFITIM code of van Genuchten [1981] for analyzing observed column effluent data using analytical solutions of the one-dimensional equilibrium and nonequilibrium advective-dispersive transport equations. The code involves analytical solutions for semi-finite columns. The nonequilibrium solutions consider the two-region dual-porosity (bi-continuum) flow model for physical nonequilibrium and the one-site or two-site sorption models for chemical nonequilibrium. The model provides an easy to use, efficient and accurate means of determining various transport parameters by optimizing column effluent data. CFITIM represents a simple alternative to the much more comprehensive, but also more complex, CXTFIT model.
CHAIN
In addition, STANMOD 1.xx includes the modified and updated CHAIN code of van Genuchten [1985] for analyzing the advective-dispersive transport of solutes involved in sequential first-order decay reactions. Examples are the migration of radionuclides in which the chain members form first-order decay reactions, and the simultaneous movement of various interacting nitrogen or organic species.
SCREEN
This behavior assessment model of Jury et al. (1983) describes the fate and transport of soil-applied organic chemicals. The model assumes linear, equilibrium partitioning between vapor, liquid, and adsorbed chemical phases, net first order degradation, and chemical losses to the atmosphere by volatilization through a stagnant air boundary layer above the soil surface. The model is intended to classify and screen organic chemicals for their relative susceptibility to different loss pathways (volatilization, leaching, degradation) in soil and air. SCREEN requires knowledge of the organic carbon partition coefficient (K_oc), Henry's constant (K_h), and a net first-order degradation rate coefficient or the chemical half-life. These parameters for selected chemicals provided in the STANMOD software are taken from Jury et al. (1984).
3DADE
Model Selection Dialog STANMOD 2.xx includes the 3DADE code of Leij and Bradford [1994] for evaluating analytical solutions for two- and three-dimensional equilibrium solute transport in the subsurface. The analytical solutions assume steady unidirectional water flow in porous media having uniform flow and transport properties. The transport equation contains terms accounting for solute movement by advection and dispersion, as well as for solute retardation, first-order decay, and zero-order production. The 3DADE code can be used to solve the direct problem, i.e., the concentration is calculated as a function of time and space for specified model parameters, and the indirect (inverse) problem in which the program estimates selected transport parameters by fitting one of the analytical solutions to specified experimental data.
N3DADE
Graphical display of results Finally, STANMOD 2.xx also incorporates the N3DADE code of Leij and Toride [1997] for evaluating analytical solutions two- and three-dimensional nonequilibrium solute transport in porous media. The analytical solutions pertain to multi-dimensional solute transport during steady unidirectional water flow in subsurface systems of semi-infinite length in the longitudinal direction, and of infinite length in the transverse direction. The solutions can be applied also to one- and two-dimensional problems. The flow and transport properties of the medium are again assumed to be macroscopically uniform. Nonequilibrium solute transfer can occur between two domains in either the liquid phase (physical nonequilibrium) or the absorbed phase (chemical nonequilibrium). The transport equation contains terms accounting for solute movement by advection and dispersion, as well as for solute retardation, first-order decay, and zero-order production.
User Interface
A Microsoft Windows-based graphical user interface (GUI) is largely based on libraries developed for the Hydrus-1D and Hydrus-2D software packages [Simunek et al., 1998, 1999]. It manages the input data required to run STANMOD, as well as for editing, parameter allocation, problem execution, and visualization of results. All computational programs were written in FORTRAN, and the graphic interface in MS Visual C++. The pre-processing unit includes specification of all necessary parameters to successfully run the FORTRAN codes.
Both input and output can be examined using graphical tools.
File management is handled by means of a sophisticated project manager.
Post-Processing
Post-processing is also carried out in the shell.
The post-processing unit consists of simple x-y plots for graphical presentation of the results (and data) and a dialog window that displays an ASCII output file.
Two and three-dimensional solutions (3DADE and N3DADE) are supported with output graphics that include 2D contours (isolines or color spectra) in areal or cross-sectional view for equilibrium, nonequilibrium, and total concentrations. Output also includes animation of graphic displays for sequential time-steps, and line-graphs for selected boundary or internal sections, and for variable-versus-time plots. Areas of interest can be zoomed into, and vertical scale can be enlarged for cross-sectional views. Viewing of grid and/or spatially distributed results (concentrations) is facilitated using high resolution color or gray scales.
Peripheral devices supported include most popular types of printers and plotters.
Extensive context-sensitive, online Help is part of the interface.
Examples distributed with the model
Direct - CXTFIT: Direct Problems
- Fig1010 - Two-region model, effect of the retardation factor, Cf(T)
- Fig1010a - Two-region model, effect of the retardation factor, Cf(Z)
- Fig1010b - Two-region model, effect of the retardation factor, Cr(Z)
- Fig1011 - Two-region model, effect of the mass transfer coefficient, Cf(T)
- Fig1011a - Two-region model, effect of the mass transfer coefficient, Cf(Z)
- Fig1011b - Two-region model, effect of the mass transfer coefficient, Cr(Z)
- Fig1012 - Two-region model, effect of the Peclet number, Cf(T)
- Fig1012a - Two-region model, effect of the Peclet number, Cf(T)
- Fig1012b - Two-region model, effect of the Peclet number, Cr(T)
- Fig105 - Equilibrium model, Effect of first-order decay, Step Input
- Fig105a - Equilibrium model, Effect of first-order decay, Pulse Input
- Fig108 - One-Site Model, Effect of mass-transfer coefficient
- Fig109 - Two-region model, effect of mobile/immobile water ratio, Cf(T)
- Fig109a - Two-region model, effect of mobile/immobile water ratio, Cf(Z)
- Fig109b - Two-region model, effect of mobile/immobile water ratio, Cr(Z)
- Fig51 - First-order nonequilibrium model, effect of beta and alpha
- Fig52 - First-order nonequilibrium model, effect of beta and f
- Fig71 - Fig.7-1: The deterministic CDE (BVP+PVP)
- Fig72a - Fig.7-2: Flux vs. (resident) conc. for the IVP, Cf(Z), (a) P=2 (b)P=10
- Fig72b - Fig.7-2: (Flux) vs. resident conc. for the IVP, Cr(Z), (a) P=2 (b)P=10
- Fig75 - Fig.7-5: Nonequilibrium one-site CDE (Beta=1/R, Alpha=0.08,0.2,1.0,10)
- Fig76a - Fig7-6a. Two-site CDE (Alpha=0.08, f=0, 0.3, 0.7, 0.99875)
- Fig76b - Fig7-6b: Two-site CDE (Alpha=0.2, f=0, 0.3, 0.7, 0.99875)
- Fig77a - Fig.7-7a: Two-site CDE for Beta.R=0.22 - Dirac input
- Fig77b - Fig.7-7b: Two-site CDE for Beta.R=0.22 - pulse input
- Fig78 - Fig.7-8: IVP for the nonequilibrium CDE
Inverse - CXTFIT: Inverse Problems
- Fig712 - Fig.7-12: Field-scale bromide movement (after Jury at al., 1982)
- Fig715 - Fig.7-15: Hypothetical field-scale reactive solute transport
- Fig73a - Fig.7-3a: Steady saturated flow in a sand column
- Fig73b - Fig.7-3b: Steady saturated flow in a sand column
- Fig74 - Fig.7-4: Estimation of duration time (MASS = 1 in Block B)
- Fig79a - Fig.7-9a: Tritium effluent curve from Glendale clay loam
- Fig79b - Fig.7-9b: Boron effluent curve (exp.3-1, van Genuchten, 1974)
Stochast - CXTFIT: Stochastic Problems
- Fig45a - Fig4.5: Stream tube model (STM) with a random v, BVP vs (IVP)
- Fig45b - Fig4.5: Stream tube model (STM) with a random v, (BVP) vs IVP
- Fig47a - Fig4.7: STM with a random v, Constant and (variable) duration
- Fig47b - Fig4.7: STM with a random v, (Constant) and variable duration
- Fig710 - Fig.7-10: STM with a random v, Effect of sigma v
- Fig711a - Fig.7-11: STM with a random v, ensemble-averaged flux conc.,
- Fig711b - Fig.7-11: STM with a random v, field-scale flux conc., cf
- Fig711c - Fig.7-11: STM with a random v, field-scale resident conc., cr
- Fig713 - Fig.7-13: STM with a random v and Kd, effect of correlation v-Kd
- Fig714a - Fig.7-14: Nonequilibrium field-scale transport (Mode=4), field-scale cr
- Fig714b - Fig.7-14: Nonequilibrium field-scale transport (Mode=4), field-scale ct
Chain - First-Order Decay Chains
- Nitrogen - Example 1: Nitrogen chain (Cho, 1972)
- Radionuc - Example 2: Radionuclide Transport
CFitM - Equilibrium Examples
- Direct1 - Effect of Peclet Number
- Direct2 - Effect of Retardation Factor
- Example1 - Example 2A: Chromium (Column Number 4) - Semi-Finite Sytem
- Example2 - Example 2B: Chromium (Column Number 4) - Finite Sytem
CFitIm - Nonequilibrium Examples
- Direct1 - Effect of Peclet Number
- Direct2 - Effect of Retardation Factor
- Direct3 - Effect of Mobile-Immobile Fraction
- Direct4 - Effect of Mass Transfer Coefficient
- Direct5 - Effect of Pulse Time
- Example1 - Nonequilibrium model, generated data
- Example2 - Example 2D: Tritiated water (EXP. 5-2); Nonequilibrium Model
- Example3 - Example 2H: Tritiated water (EXP. 5-2); Linear Adsorption
- Fig79a - Tritium effluent from Glendale clay loam; Nonequilibrium model
- Fig79b - Boron effluent (exp.3-1, van Genuchten, 1974); Nonequilibrium model
3DADE - Three-dimensioal equilibrium transport
- Example1 - Diffuse source in semi-infinite region of surface, Steady-S.
- Example2 - Rectangular source at surface, First-type BC
- Example3 - Rectangular source at surface, Third-type BC
- Example4 - Parallelepipedal initial distribution, Third-type BC
- Example5 - Circular source at surface, Third-type BC
- Example6 - Diffuse source in semi-infinite region of surface, First-type BC
- Example7 - Parallelepipedal initial distribution, Third-type BC
- Example8 - Parallelepipedal initial distribution, Third-type BC
- Example9 - Circular source at surface, First-type BC
N3DADE - Three-dimensional nonequilibrium
- Exampl1a - BVP: Fig. 6: Instantaneous application from disc (cm,d)
- Exampl1b - BVP: Fig. 7: Instantaneous application from disc (cm,d)
- Exampl1c - BVP: Fig. 7: Instantaneous application from disc (cm,d), new output
- Exampl2a - BVP: Fig. 8: Heaviside application, Finite rectangle
- Exampl2b - BVP: Fig. 9: Heaviside application, Finite rectangle
- Example3 - IVP: Fig. 10: Heaviside initial, Finite rectangle
- Example4 - IVP: Fig. 11: Exponential distribution about (5,0,0), Spherical coordinate
- Example5 - PVP: Fig. 12: Heaviside production, Circular coordinate
Screen - Screening Model
- Test1 - Toluene: multiple fluxes
- Test2 - Benzene: Multiple times
- Test3 - Multiple solutes
System Requirements
Intel Pentium or higher processor, 16 Mb RAM, hard disk with at least 20 Mb free disk space, VGA graphics (High Color recommended), MS Windows 95, 98, NT, 2000, XP, Vistas
The STANMOD software was designed for Windows XP and we do not guarantee its compatibility with newer Windows systems (e.g., Win10, 64 bit)
STANMOD References
- Jury, W. A., W. F. Spencer, and W. J. Farmer, Behavior assessment model for trace organics in soil: I. Description of model. J. Environ. Qual., 12(4), 558-564, 1983.
- Jury, W. A., W. F. Spencer, and W. J. Farmer, Behavior assessment model for trace organics in soil: III. Application of screening model, J. Environ. Qual., 13(4), 573-579, 1984.
- Leij, F. J., and S. A. Bradford, 3DADE: A computer program for evaluating three-dimensional equilibrium solute transport in porous media, Research Report No. 134, U. S. Salinity Laboratory, USDA, ARS, Riverside, CA, 1994. ( Download PDF, 7Mb)
- Leij, F. J., and N. Toride, N3DADE: A computer program for evaluating nonequilibrium three-dimensional equilibrium solute transport in porous media, Research Report No. 143, U. S. Salinity Laboratory, USDA, ARS, Riverside, CA, 1997. ( Download PDF, 10Mb)
- Leij, F. J., and N. Toride, Analytical solutions for nonequilibrium transport models, in Selim, H. M., and L. Ma (eds.) Physical Nonequilibrium in Soils, Modeling and Application, Ann Arbor Press, Chelsea, Michigan, 1998.
- Marquardt, D. W., An algorithm for least-squares estimation of nonlinear parameters, SIAM J. Appl. Math. 11, 431-441, 1963.
- Parker, J. C., and M. Th. van Genuchten, Determining transport parameters from laboratory and field tracer experiments, Bull. 84-3, Va Agric. Exp. St., Blaacksburg, Va, 1984.
- Šimůnek, J., M. Th. van Genuchten, M. Šejna, N. Toride, and F. J. Leij, The STANMOD computer software for evaluating solute transport in porous media using analytical solutions of convection-dispersion equation. Versions 1.0 and 2.0, IGWMC - TPS - 71, International Ground Water Modeling Center, Colorado School of Mines, Golden, Colorado, 32 pp., 1999.
- Toride, N., F. J. Leij, and M. Th. van Genuchten, The CXTFIT code for estimating transport parameters from laboratory or field tracer experiments. Version 2.0, Research Report No. 137, U. S. Salinity Laboratory, USDA, ARS, Riverside, CA, 1995.
- van Genuchten, M. Th., Determining transport parameters from solute displacement experiments, Research Report No. 118, U. S. Salinity Laboratory, USDA, ARS, Riverside, CA, 1980. ( Download PDF, 2.7Mb)
- van Genuchten, M. Th., J. Šimůnek, F. L. Leij, N. Toride, and M. Šejna, STANMOD: Model use, calibration and validation, special issue Standard/Engineering Procedures for Model Calibration and Validation, Transactions of the ASABE, 5(4), 1353-1366, 2012.