Author(s):

Abstract:

VADOFT is a finite-element code that simulates one-dimensional, single-phase moisture and solute transport in unconfined, variably saturated porous media. Transport processes include hydrodynamic dispersion, advection, linear equilibrium sorption, and first-order decay. VADOFT employs the Galerkin finite-element technique to approximate the governing equations for flow and transport and allows for a wide range of nonlinear flow conditions. Boundary conditions of the variably saturated flow problems may be specified in terms of prescribed pressure head or prescribed volumetric water flux per unit area. Boundary conditions of the solute transport problem may be specified in terms of prescribed concentrations of prescribed solute mass flux per unit area. All boundary conditions may be time dependent. An important feature of the algorithm is the use of constitutive relationships for soil water characteristic curves based on soil texture.

Limitations:
Hysteresis effects in the constitutive relationships are assumed to be negligible. Sorption and decay of the solute are described by a linear equilibrium isotherm and a lumped first-order decay constant. The code considers only single porosity soil media and does not simulate flow or transport in fractured porous media or structured soils.

Validation:
Three sets of benchmark problems were used to test the VADOFT code; numerical results from VADOFT were compared with analytical solutions and results using two other finite-element codes (MULLINS et al. 1993).

Source of the Abstract:

Mullins, J.A., R.F. Carsel, J.E. Scarbrough, A.M. Ivery. 1993

II. Technical Information

II.1 Executables:

II.2 Source-code:

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

V. Further information in the World-Wide-Web

• PRZM2

VI. Additional remarks

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