Institute of Arid Regions (IRA) - Tunisia
6th World Water Forum
Marseille, 12-17.03.2012
Low cost
Solutions for the Irrigation Efficiency
improvement in the Maghreb oasesStudy case of Southern Tunisia
Nizar Omrani & Prof. Dr. Dieter Burger
IfGG, Karlsruhe Institute of Technology (KIT)
Context:
In the arid lands of the Maghreb countries (Tunisia, Algeria and Morocco), the oases still
represent very particular irrigated perimeters with high crop production potential.
Nevertheless, under the water shortage context, the irrigation management became a
crucial issue that preconditions the development of the oases. The efficiency of the surface
irrigation and the water productivity inside farmers plots remained low and are focusing a
cross disciplinary commitment from research and development actors.
For the case of southern Tunisia, as well as for the neighbors countries, the introduction of
the sprinkler and the drip irrigation for the main cultivations systems which is the date palm,
remains definitely a technical challenge and requires relevant installation costs.
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Kit Solution Description:
The solution had been initiated within the framework of the cooperation between the
Karlsruhe Institute of Technology (KIT), the institute of Arid Regions (IRA) and the
German technical Cooperation (GIZ).
The test in pilot farms of the irrigation systems (near surface sprinkler design) of PVC
pipes using simply the water borne delivered discharge (less than 0.5 m) had been
implemented in Atilet, kebili Oasis in the southern Tunisia.
Kit Solution Description:
The design of the irrigation systems could be easily by the local development agency
supervised, the plastic materials are also simply in local markets available.
Farmers training by the Governmental vulgarization agencies and the German technical
cooperation for the water saving practice inside farms is highly recommended prior to the
irrigation kit implementation.
The technical installation of those irrigation techniques could be operated by the
farmers community often organized in common interest groups (GIC). It should be than
supervised by the local agriculture development organization for technical maintenance.
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Low Cost Irrigation Kit Design
Alternative 1: 2nd order Distributing
pipe + basin irrigation; less
effective, but relative cheap
Alternative 2: 3rd order ‚punched‘
distribution pipe with holes e.g. every
one meter
Alternative 3: Two line distribution
pipe for better water distribution
Alternative 4: Two line distribution pipe
with near-surface sprinklers.
Precondition: 40 cm distance in height
(0.4 bar needed)
alternative 1
= Pipe PVC, ø= 63 mm
= Head Indicator
= Outlet 63 mm
alternative 2
alternative 3
= Pipe PVC, ø= 63 mm
= Outlet 50 mm
= Pipe PVC, ø= 50 mm
= Head Indicator
Connexion to the public
irrigation network
Oasis Rejim Maatoug, Tunisia
A
Photo: Ghazouani, 2007
B
Conversion from submersion method (A) to
Low cost irrigation systems (B, C) implemented
in Atilet, Kebili-Southern Tunisia
C
Photo: Omrani, 2011
Conditions for success:
National policies in the irrigated sector emphasizes on the framer’s plots irrigation
performance improvement. Several subsidies are being allocated to encourage the
implementation of the water saving techniques inside farmer’s plot (20 %, 40 % and 60
% of the installation cost respectively for the big, medium and small farms).
The presence of Farmer’s group’s structure already good organized which would
facilitate the implementation of the solution within the oases.
There is a real demand from the farmers group of concrete tools to enhance the
parcels productivity and to overcome the water shortage in the summer period when
the irrigation network become unable to satisfy the demand (high infiltration rate
during the surface irrigation in the farmers plots).
The added value:
The introduction of low cost irrigation system for more water saving approach. The
irrigation efficiency at the parcel more than 80 % while it had been 60 % in best case with
the former improved surface method.
With the conventional drip irrigation material, there are recurrent problems of drippers
warping by salt especially in summer period, our irrigation kit avoid such constraint, the
near-surface sprinklers provide a uniform water application in the irrigation basin.
With a strict application of the recommended low cost irrigation technique , the water
productivity attempts 0,51 kg/m3 while it could be, according to the state of art
(Simmoneau, 1961), nearby 0,25 kg/m3.
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Depending on the irrigation design types that could be recommended from our panel,
the installation cost for an irrigated range from 1220 €uro/ha to 2800 €uro/ha.
There is no need to pumping, relevant energy costs are spared. The water supply could be
operated with the discharge prevailing in the irrigation network. Nevertheless, considering
the technical constraints that could afford such technique, the implementation of storage
reservoir provide (0.4 to 0.5 m discharge) provides more flexibility for farmers to manage
his parcel irrigation.
Replication potential:
This irrigation kit could installed within all the oases as alternative to the traditional
surface method.
With use of brackish water, such irrigation system avoid the warping problem and the
salt crust formation as it is the case with the conventional drippers.
Tunisia, Algeria and Lybia are using a common underground water resources SASS,
such brackish water requires the recourse to alternative irrigation systems to resolve
the mentioned problems.
The prevailing water management condition in the Maghreb countries oases as well as
the well structured irrigation scheme of these arid lands, reinforce the up scaling
potential of such solution.
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Contact:
omrani_nizar@yahoo.fr
Dieter.Burger@kit.edu