WellDrain:   Spacing of wells (vertical drains) in subsurface drainage systems for watertable and soil salinity control in irrigated agricultural lands
Totally free download and use of software

The WellDrain computer program calculates the drainage discharge by wells, hydraulic head, hydraulic conductivity, or spacing between pumped wells (open dug wells, tubewells, vertical drainage) and shows the curvature of the watertable (water-table).
      The computations are needed for the design of subsurface drainage systems by open wells or tube-wells of rainfed or irrigated agricultural land and soil salinity control. The wells may be partially or fully penetrating the aquifer.
      On 10 August 2010 the program was improved thanks to comments of Nicolas Deeks.
On 13 June 2011 the program was expanded to include a rectangular layout of the well field under the option "Calculate hydraulic head", thanks to questions asked by Michael Conley.
      On 11 August 2012 the WellDrain software was completely integrated under Delphi, so that the auxiliary *.exe files in Fortran were no longer required and the program size was considerably reduced.
      On 23 November 2012 the facility to calculate the hydraulic conductivity was included, so that the program can be used for evaluation of a pumping test, well test, or aquifer test.
On 4 February 2014 the titles of the data to be entered in the input tabsheet have been improved thanks to a feed back by Malcolm Woodruff.

The well spacing calculations are based on the traditional concepts of the Darcy and waterbalance (water balance, budget) or mass conservation equations.
      The program allows for the presence of three different soil layers with different hydraulic conductivity and permeability: one layer above and two below drain level. The last two layers can also have different horizontal and vertical hydraulic permeability (anisotropy). Examples are given.
      WellDrain can be used in case of waterlogging (water logging) and for the reclamation (remediation, rehabilitation, restoration) of saline (salty) soils.
The simulation software is totally free for download and use. It can be called shareware (freeware) and is in public domain.

The program starts clicking on WellDrain.Exe.
More information is found in the program itself.

A description of the physical, numerical and mathematical theory of groundwater (ground-water) flow to pumped drainage wells and vertical drainage can be consulted here.
For the determination of hydraulic aquifer properties from pumping tests by wells one may consult the publication "Software for Aquifer Test Evaluation, SATEM" by J.Boonstra and R.A.L.Kselik. For free download go to the download page.
A comparison of required drain and well spacings for horizontal resp. vertical drainage under the same conditions can be seen in the spacings page.

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


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control of the groundwater
       table Screenprint of figure in WellDrain program
In this application software, the well spacing and discharge depend on the hydraulic conductivity of the soil (K), the depth of the water table (Dm), the position of the impermeable layer, the diameter (W) and depth of the wells (Db), as well as the depth of the water level in the well (Dw). The WellDrain model calculates all these relations and comes up with the well spacing.

wells can be used as
           drains Example of results of WellDrain model
As can be seen from the program application, the depth of the water table diminishes with the distance from the wells. Midway between the wells (at half the distance of the well spacing) the water table is flat, elsewhere it is curved.