SaltMod

A mathematical, numerical simulation model describing the relations between
agriculture, crop rotation, irrigation, rainfall, potential and
actual evaporation (evapotranspiration), climate, hydrology,
depth and level of watertable, capillary rise, deep percolation, soil
salinity and subsurface drainage by drains or wells, and reuse (conjunctive use)
of ground and drain water from wells. It includes farmers' responses
to water logging and soil salinity.

SahysMod

A combination of Saltmod with a model of ground water flow and hydraulics
to account for large spatial variation through a network of polygons.
It includes phreatic (unconfined) aquifers as well as soil layers with slow
vertical hydraulic conductivity (soil permeability for water) resulting in
semiconfined (leaky) aquifers.

SaltCalc

A simplified version of SaltMod with the advantage that calculations are made
for shorter time steps (monthly instead of seasonally). SaltCalc can be used
when field observations of irrigation, water table and soil salinity have been
made and one wishes to develop a model for that situation. Normally,
calibration of unknown values must be done using a range of values of the
corresponding variable, running the model repeatedly and selecting the optimal
value from the range that gives model results closest to observed values.

LeachMod

This model is somewhat similar to SaltCalc. On the one hand the water
management options are fewer (e.g. reuse of drainage or well water for
irrigation do not feature here), but the model is more modern in the
sense that the variable input for each time step is given in a table so that
the calculations over all the time steps are done in one go. Moreover, by
inserting the observed values of soil salinity in the data table, the model
optimizes the leaching efficiency of the soil automatically.


