Science et changements planétaires / Sécheresse


Optimising a microirrigation network Volume 14, issue 3, JUILLET-AOÛT-SEPTEMBRE 2003


See all figures

Université de Blida, Faculté d‘agronomie, Blida, Algérie <lakhdarzyahoo.fr> École nationale polytechnique d‘El Harrach, Alger, Algérie

Irrigation as it is practised in Algerian oases is the source of a huge waste of water which can be highly detrimental to the environment. Microirrigation is an irrigation technique relying on a very high technology material, essentially concentrated on the emitter portion, the terminal device of the network. To enjoy the benefits offered by this technique while optimising its use, it is necessary to optimise the design of the network by correctly dimensioning it. This can be done using a theoretical model based on hydraulic analyses implementing fundamental mass and energy conservation principles. In this paper, the model is applied to a concrete example of a microirrigation network intended for a palm‐tree area situated in the Oued Righ valley in South‐Eastern Algeria. The model simulates the operation of the network according to a set pattern and offers the opportunity to test several design solutions and geometric structures, thereby allowing the optimal network to be chosen. The network thus built allows the water to be uniformly distributed to the palm‐trees while meeting water needs. Water and pumping energy resources as well as fertilization volumes are in turn reduced to their optimal level. In the present example, on the basis of a production of 40 kg\palm‐tree, 1 kilogram of dates uses up 1 to 2 m 3 of water against 4 to 6 m 3 in a classical irrigation context. Depending on water peak demands, the irrigation of this area (0.54 hectare) consumes 10 900 m 3 and requires 630 kWh of pumping energy, i.e. the equivalent of 2,520 DA for a 10‐month irrigation period.