GGSD Program Details for HYDRUS-2D

HYDRUS-2D

Category	Contaminant transport (2D FD)
Publisher	USDA Salinity Laboratory
Platform	Win3x
Status	Commercial
Description	HYDRUS-2D is a 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. Optionally, includes a mesh generator for unstructured finite element grids, MESHGEN-2D. SWMS_2D numerically solves the Richards' equation for saturated-unsaturated water flow and the Fickian-based advection-dispersion equation for solute transport. The flow equation incorporates a sink term to account for water uptake by plant roots. The transport equation includes provisions for linear equilibrium adsorption, zero-order production, and first-order degradation. The program may be used to analyze water and solute movement in unsaturated media. It can handle flow regions delineated by irregular boundaries. The flow region itself may be composed of non-uniform soils having an arbitrary degree of local anisotropy. Flow and transport can occur in the vertical plane, the horizontal plane, or in a three-dimensional region exhibiting radial symmetry about the vertical axis. The water flow part of the model can deal with (constant or varying) prescribed head and flux boundaries, as well as boundaries controlled by atmospheric conditions. Soil surface boundary conditions may change during the simulation from prescribed flux to prescribed head type conditions (and vice-versa). The code can also handle a seepage face boundary through which water leaves the saturated part of the flow domain, and free drainage boundary conditions. Nodal drains are represented by a simple relationship derived from electric analog experiments. For solute transport the code supports both (constant and varying) prescribed concentration (Dirichlet or first-type) and concentration flux (Cauchy or third-type) boundaries. The dispersion tensor includes a term reflecting the effects of molecular diffusion and tortuosity. Output graphics include 2D contours (isolines or color spectra) in areal or cross-sectional view for heads, water content, velocity, and concentrations. Output also includes 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. A free demonstration version is available on the WWW.
Cost	US Dollars 1200
Data formats supported	None stated
Supplier in United States of America	International Ground Water Modeling Center
Supplier in United States of America	USDA Salinity Laboratory