GGSD Program Details for VS2D/T

VS2D/T

Category	Contaminant transport (2D FD)
Platform	DOS
Status	Commercial
Description	VS2D/T is a two-dimensional finite difference simulator for cross-sectional or cylindrical variably saturated flow in porous media. The model allows consideration of non-linear storage, conductance, and sink terms and boundary conditions. Processes included are infiltration, evaporation and plant root uptake. The program also handles seepage faces. It is a solute transport module to be used with VS2D. It is based on a finite difference approximation of the advection-dispersion equation for a single species. Program options include first-order decay, equilibrium adsorption described by Freundlich or Langmuir isotherms, and ion-exchange. Nonlinear storage terms are linearized by an implicit Newton-Raphson method. Nonlinear conductance terms, boundary conditions, and sink terms are linearized implicitly. Relative hydraulic conductivity is evaluated at cell boundaries by using full upstream weighting, the arithmetic mean, or the geometric mean of values of adjacent cells. Saturated hydraulic conductivities are evaluated at cell boundaries by using distance weighted harmonic means. The linearized matrix equations are solved using the strongly implicit method. Nonlinear conductance and storage coefficients are represented by closed-form algebraic equations or interpolated from tables. Nonlinear boundary conditions treated by the code include infiltration, evaporation, and seepage faces. Extraction by plant roots is included as a nonlinear sink term. Initial conditions may be input as moisture content or pressure head by blocks defined by row and column, or in a formatted file by cell. An equilibrium profile may be specified above a user defined free water surface. Infiltration may be simulated by specified flux nodes, specified pressure nodes, or a ponding function where the user specifies rainfall rate and ponding height. Evaporation is simulated by a user defined potential evapotranspiration, pressure potential of the atmosphere, and surface resistance. Evapotranspiration is simulated through the use of user defined potential evapotranspiration, minimum root pressure, depth of rooting, and root activity at the bottom of the root zone and land surface. Seepage faces may also be simulated.
Cost	US Dollars 250
Data formats supported	None stated
Supplier in United States of America	International Ground Water Modeling Center
Supplier in United States of America	Scientific Software Group