1. General Model Information

Name: UNSAT2

Acronym: UNSAT2

Main medium: terrestrial
Main subject: biogeochemistry, hydrology
Organization level: ecosystem
Type of model: partial differential equations (finite elements,2D)
Main application:
Keywords: soil, unsaturated, saturated, water transport, nonuniform soil, anisotropy, porous media, evapotranspiration, richards equation, transient state, finite element numerics, anisotropy


S.P. Neuman
Department of Hydrology and Water Resources
University of Arizona
Tucson, AZ 85721
Phone: (520) 621-7114
Fax :
email: shlomo-neuman@ns.arizona.edu

Dr. Reinder Feddes
Dept. of Water Resources
Agricultural University
Wageningen, 6709PA
The Netherlands Phone: 31 8370 82875
Fax: 31 8370 84885
email: Reinder.Feddes@users.whh.wau.nl


Neumann, S.P., R.A. Feddes, E. Bresler


UNSAT2 is a two-dimensional finite element model for horizontal, vertical, or axisymmetric simulation of transient flow in a variably saturated, non-uniform anisotropic porous medium. The governing equation is the Richard's equation expressed in terms of pressure head. Boundary conditions included are Dirichlet and Neumann, and seepage face. UNSAT2 is capable of simulating infiltration and evaporation as head-dependent conditions, determined after the fluid pressure is calculated. Evapotranspiration is simulated through user specified minimum allowed pressure head at the soil surface, maximum evaporation rate, and soil surface geometric data. User supplied input for simulation of evapotranspiration includes root zone geometric data, root effectiveness function, plant species wilting pressure, and maximum transpiration rate. The code can use both quadrilateral and triangular elements. Unsaturated hydraulic properties must be input in table form: internally, the code uses linear slopes between the data points for interpolation. UNSAT2 has a restart feature for simulating changing boundary conditions.

Please note that there are (at least) two other Models named "UNSAT", viz. the one dimensional finite element code UNSAT-1 by M.Th. van Genuchten and the 1D finite difference model UNSAT-H "Unsaturated Soil Water and Heat Flow Model" by M. J. Fayer and T. L. Jones 1990.

II. Technical Information

II.1 Executables:

Operating System(s):

II.2 Source-code:

Programming Language(s):

II.3 Manuals:

II.4 Data:

III. Mathematical Information

III.1 Mathematics

III.2 Quantities

III.2.1 Input

III.2.2 Output

IV. References

Davis, L. A., and S. P. Neuman. 1983. Documentation and user's guide: UNSAT2 - Variably saturated flow model, Final Report, WWL/TM-1791-1, Water, Waste& Land Inc., Ft. Collins, Colorado.

Neuman, S.P., R. A. Feddes, and E. Bresler 1974. Finite element simulation of flow in saturated-unsaturated soils considering water uptake by plants, Third Annual Report, Project No. A10-SWC-77, Hydraulic Engineering Lab., Technion, Haifa, Israel.

Neuman, S. P. 1973. Saturated-unsaturated seepage by finite elements. Proc. ASCE, J. Hydraul.Div. 99(HY12):2233-2250.

V. Further information in the World-Wide-Web

VI. Additional remarks

Last review of this document by: T. Gabele: 17. 07. 1997 -
Status of the document:
last modified by Tobias Gabele Wed Aug 21 21:44:51 CEST 2002

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