1. General Model Information

Name: HYDRUS-2D Version 1.0

Acronym: HYDRUS2D

Main medium: terrestrial
Main subject: hydrology, biogeochemistry
Organization level: ecosystem
Type of model: partial differential equations (finite elements,2D), ordinary differential equations
Main application:
Keywords: water flow, solute transport, unsaturated, porous media, saturated, equilibrium adsorption, solute transport, zero-order production, first order degradation, water uptake, solute uptake Richards equation, convection-dispersion equation, sink terms, Garlekin finite element numerics, Windows- interface


Walter Russell
U.S. Salinity Laboratory, USDA, ARS
450 West Big Springs Road
Riverside, CA 92507-4716Tel: 909-369-4850
FAX: 909-342-4964
email: wrussell@ussl.ars.usda.gov

Simunek, J.
U. S. Salinity Laboratory, USDA, ARS
450 West Big Springs Road
Riverside, CA 92507-4617


J. Simunek, M. Sejna, and M.Th. van Genuchten
U.S. Salinity Laboratory, USDA/ARS, Riverside, California


J. Simunek, M. Sejna, and M.Th. van Genuchten
U.S. Salinity Laboratory, USDA/ARS, Riverside, California

HYDRUS-2D is a Microsoft Windows based modeling environment for analysis of water flow and solute transport in variably saturated porous media. It includes the two-dimensional finite element model SWMS_2D for simulating flow and solute transport in variably saturated media. The model is supported by an interactive graphics-based interface for data-preprocessing, generation of a structured mesh, and graphic presentation of the results. Optionally, the modeling environment includes an mesh generator for unstructured finite element grids, MESHGEN-2D. The MS Windows based Graphics User Interface (GUI) manages the geographical, hydrogeologic and physical inputs required to run SWMS-2D, as well as grid design and editing, parameter allocation, problem execution, and visualization of results.

The program includes a set of controls that allow the user to build a flow and transport model and perform graphical analyses on the fly. Both input and output can be examined using areal or cross sectional views, and line graphs. The HYDRUS-2D shell program translates all geometric and parameter data into the SWMS-2D input format. File management is handled by a sophisticated project manager.
Automatic Mesh Generation
Data preprocessing involves specification of the flow region having an arbitrary continuous shape bounded by polylines, arcs and splines, discretization of domain boundaries, and subsequent generation of an unstructured finite element mesh. HYDRUS-2D comes with an optional mesh generation program MESHGEN-2D by PC-Progress. This program, based on Delaunay triangulation, is seamlessly integrated in the HYDRUS-2D environment. In the absence of the MESHGEN-2D program, the HYDRUS-2D shell provides an option for automatic construction of simple, structured grids.
Post-processing is also done in the shell. Areas of interest can be zoomed into, and vertical scale can be enlarged for cross-sectional views. Output graphics include 2D contours (isolines or color spectra) in areal or cross-sectional view for heads, water content, velocity, and concentrations. Included are velocity vector plots, animation of graphic displays for sequential timesteps, and linegraphs for selected boundary or internal sections, and for variable-versus-time plots. The mesh can be displayed with boundaries, and numbering of triangles, edges and points. Observation points can be added anywhere in the grid. Viewing of grid and/or spatially distributed results (pressure head, water content, velocity, or concentration) is facilitated using high resolution color or grey scales.

II. Technical Information

II.1 Executables:

Operating System(s): SYSTEM REQUIREMENTS: Ordering Information, DISTRIBUTOR: International Groundwater Modeling Center (IGWMC) Colorado School of Mines, Golden, Colorado.

II.2 Source-code:

Programming Language(s): International Groundwater Modeling Center (IGWMC) Colorado School of Mines, Golden, Colorado. The kernel SWMS-2D is written in FORTRAN 77, which can becompiled and run on any PC compatible computer. The 3-d Version SWMS-3D and manual are available upon request from wrussell@ussl.ars.usda.gov The SWMS-3D code comes with a user manual giving detailed instructions for data input preparation. Example input and output files are also given, as is a listing of the source code.

II.3 Manuals:

see section II.1 and II.2, Extensive context-sensitive, on-line Help is part of the interface.

II.4 Data:

Included in the program is a small catalog of soil hydraulic properties.

III. Mathematical Information

III.1 Mathematics

III.2 Quantities

III.2.1 Input

III.2.2 Output

IV. References

Simunek. J., Vogel T., van Genuchten M.Th., 1994. The SWMS_2D code for simulating water flow and solute transport in two-dimensional variably saturated media, Version 1.21. Research Report No. 132, 197 p., U.S. Salinity Laboratory, USDA, ARS, Riverside, California.

V. Further information in the World-Wide-Web

VI. Additional remarks

Last review of this document by: T. Gabele: 07.07. 1997 -
Status of the document:
last modified by Tobias Gabele Wed Aug 21 21:44:44 CEST 2002

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