SahysMod :   Spatial agro-hydro-soil-salinity and ground-water (groundwater) model based on a system of polygons
Totally free download of software

Summary: Sahysmod is a mathematical (numerical) computer program (model) for simulation and prediction of the salinity of soil moisture, ground and drainage water, the flow of groundwater, depth of the water table and the drain discharge in irrigated agricultural lands under various geohydrologic conditions, varying water management options, including the re-use of ground water for irrigation by pumping from wells (conjunctive use), and several crop rotation schedules. The aquifer may be unconfined (phreatic) or semi confined leaky). The spatial variation is accounted for by a nodal network of polygons.

General: Sahysmod combines the agro-hydro-soil-salinity model SaltMod and an adjusted/extended polygonal groundwater (ground water) model SGMP of my colleague Dr.J.Boonstra. It allows for the introduction of unconfined (phreatic) and semiconfined (semi-confined, leaky) aquifers.
      The modelling (modeling) helps in determining sustainable land use and environmentally sound watermanagement (water management) for sustainability.
      When the maximum number of polygons (300) is used, the data base becomes quite large. The latest version has improved network-making functions and a version with more than 300 polygons can be made available on request.

Details: The model calculates waterbalances (water balances, budgets), actual from potential evaporation (evapotranspiration), capillary rise, deep percolation, and groundwater (ground water) flow.
      Optionally, farmers' responses can be simulated adjusting agriculture and irrigation to waterlogging (water logging) and salinity.
During May 2005, Mr. Juan Manuel Mendía and Mr. Javier Sassi, Comahue University, Rio Negro, Argentina, have made considerable efforts to test the input menu. As a result it was adjusted in many instances. I would like to express my gratitude to both gentlemen.
  ;    In September 2006 I visited the university of Bonn (Germany) where the model is used for assessment of watermanagement (water management) in a valley in Marocco (reference). As a result the model was further improved and extended to accommodate particular situations.
      In November 2008 the guided procedure for construction of the polygonal network was improved thanks to the efforts of Mr. Tsegay Fithanegest Desta who applied the model in NE Thailand (reference) . Again, the procedure was extended as a result of comments by Mrs. Francesca Verones from Switzerland.
      On 20 September 2011 the program was given the facility to bring the rotation type under the farmers' responses, which resulted in version 1.3.3
On 24 September 2011 the general input interface, in some cases, was given a multiple choice box instead of an edit box.
      On 3 July 2012 SahysMod was totally brought under Delphi so that the auxiliary Fortran files are no longer required and the size of the package was considerably reduced. This is version 2.1.1. On 25 Novenber 2012 also the option was given to paste polygonal coordinates from the clipboard.

Mapping: The program provides graphs. For mapping options see the hint below or the facilties text.
      Also, the option is given to produce *.prn text files of input and output features which can be used in GIS, CAD, and other contour (isoline) mapping programs.
A free and simple program for this purpose is, for example, QuikGrid (yes, not QuickGrid). For a guide and examples of mapping with QuikGrid see Mapping Guide or, with more detail, Case studies .

Start: The program starts clicking on Sahysmod.Exe. More information is given in the program itself.

Experiences: For improvement, I am interested to learn about your experiences with SahysMod. For this, there is a contact form.

Update: Thanks to suggestions made by Sue Guo, on 15 January 2018, SahysMod was given additional facilities for annual calculations whereby the annual input files are automatically created and opened.

Since November 2017 the model includes mapping options (see examples below). This version also contains a larger number of crop rotation options.

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salinity and
           groundwater The manual contains the principles, theory, user menu and examples of application. It can be downloaded from the manual page

The manual for the user interface on the menu of the software is to be found on the menu page

The table of contents of the manual can be seen on-line.

Also, the introduction of the SahysMod manual can be viewed on line as a .PDF document.

In addition, a PowerPoint slide show can be viewed on-line or downloaded.

Publications in which SahysMod is used can be downloaded from this list
groundwater seepage

  Polygonal input screen of SahysMod program:

input to soil salnity
The required data per polygon are polygonal characteristics, hydraulic conductivity and soil porosity.
Further data needed are leaching efficiency, parameters of the drainage system, and capillary rise factors.
Seasonal data encompass rainfall, irrigation and evaporation.

Example of output graph showing areal changes

output of salty capillary rise
           simulation The depth of the watertable can be seen in the output in a row of nodes at a certain time, or in one node over the whole time period.
The same holds for the soil salinity in the different soil layers, the amount of groundwater flow and the irrigation efficiency.
There are many more output data.

Example of output graph showing time changes.

      flow Output graphs can be seen for polygons at a certain time as well as for period of time in a certain polygon.
This graph shows the fluctuation in time of various components of groundwater flow in one of the polygons.

Example of watertable output Map

output of salinity map The soil salinity in the irrigated alluvial fan of Garmsar (Iran) was simulated with SahysMod using a nodal network and an example of results is shown here for Cr4 being the soil salinity of, from year to year, fully rotated cropped areas.  

Example of salinity output Map

output of salinity map The depth of the water table in the irrigated alluvial fan of Garmsar (Iran) was simulated with SahysMod using 89 polygons and an example of results is shown here.