Summary:
The EnDrain computer program calculates the
drainage discharge, hydraulic head, or spacing
between parallel subsurface (sub-surface) drains:
pipe/tile drains or open ditches, with or without
entrance resistance and shows the curve of the
shallow watertable (water-table).
The computations are needed
for the design of subsurface drainage systems
of rainfed or irrigated agricultural land for
waterlogging (water logging), watertable
(water table) and soil salinity control.
EnDrain can be used for the
reclamation (remediation, rehabilitation,
restoration) of saline (salty) soils.
The simulation software is free for download. It
can be called shareware (freeware) and is in
public domain.
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Details:
The drainage equation used is an amplified
version of Hooghoudt's equation.
The drain spacing
calculations are based on the
concept of the energy balance of groundwater
(ground-water) flow. However, the traditional
concepts based on the Darcy and waterbalance
(water balance, budget) or mass conservation
equations are also used.
An article on the correspondence between the
energy balance and the law of Joule in
electricity can be found using
this link
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 conductivity or
permeability (anisotropy).
Examples are given.
On 21 May 2012 the auxiliary Fortran programs of
the EnDrain model were eliminated and the
contents were integrated into the Delphi program.
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Start:
The program starts clicking on EnDrain.Exe.
More information is given in the program itself.
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Acknowledgements:
On 10 August 2010 the program was improved thanks
to comments of Nicolas Deeks.
On 14 June 2011 the user interface was improved
thanks to a request of Robin Johnston.
On 17 May 2012 the EnDrain program was improved
thanks to suggestions by Pepe del Monte.
On 30 June 2017 the input menu was given a
Help-Recharge function at a comment of
Cuthbert Taguta
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Documentation:
Publications on the physical and mathematical
theory of the energy balance of groundwater
(ground-water) flow and examples of EnDrain
applications are found on the
articles page or
directly as energy
or balance
PDF documents.
A list of publications using EnDrain is found on
this 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.
An article on the use of EnDrain for
subsurface land drainage by pipes was published
in the International Journal of Research in
Agriculture and Forestry:
Subsurface drainage
equations using the full energy balance of
groundwater flow in layered and/or anisotropic
soils. A similar article, with emphasis on
ditches, can be seen at
this site.
The EnDrain software can be helpful in the
determination of the parameters (e.g. spacing)
of agricultural subsurface drainage systems as
explained in the
EnDrain paper.
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Hint:
When it is required to sumulate the drain discharge
as a function of time, given a time sequence of
rainfalls of irrigation applications, use can be
made of the hydrological runoff model
RainOff. It gives an
example of drain discharge simulation in the
"Data" file. The drainage system is to be
characterised by a response function (or reaction
factor) alpha = A * runoff + B, as can be seen
using the option "Predict discharge or runoff
from rainfall given the alpha function" in the
input tabsheet.
See the example in the last figure hereunder.
The RainOff program gives also a time series of
hydraulic heads (water levels) in the output file.
These data can be used to depict the fluctuation
of the level of the water table with time.
A comparison of results of EnDrain and RainOff for
steady and non-steady state drainage flow and
water level can be consulted at
ResearchGate or on this
website
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See also:
For the calculation of the soil's hydraulic
conductivity based on measurements of the
discharge and ground water level in
agricultural subsurface drainage systems,
use can be made of the
HydrCond
calculator.
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Experiences:
For improvement, I am interested to learn about
your experiences with EnDrain. For this there is
a contact form.
The software site
Actiweb shows a summary of the user interface of Endrain in Spanish.
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