Insert Nodal Drains

Inserts a Nodal Drain and specifies its parameters.

A special system-dependent boundary condition is sometimes implemented in one-dimensional numerical models (e.g., van Dam et al., 1997; Šimùnek et al., 2005) to account for flow to horizontal subsurface tile drains (Figure above). An equivalent drainage flux from the bottom of the simulated soil profile is then calculated using an appropriate analytical solutions for the tile drainage system (e.g., Houghoudt, 1940; Ernst, 1962; van Hoorn, 1997). The drainage equations involved generally hold for steady-state flow into the drain and depend upon the geometry of the system (e.g., depth of tile drain, depth to impermeable layer, location of water table midway between two drains, and possibly information about soil layering).

A nodal drain option is enabled only when simple 2D (rectangular) geometries (with structured grids) are used. One needs to have a rectangular grid around the drain for this option to work. A nodal drain option would not (and does not) work with unstructured grids as created for general geometries.

Additional information about other Domain Properties.