Scholarly article on topic 'The Impact of Traditional Irrigation (Foggara) and Modern (drip, pivot) on the Resource Non-Renewable Groundwater in the Algerian Sahara'

The Impact of Traditional Irrigation (Foggara) and Modern (drip, pivot) on the Resource Non-Renewable Groundwater in the Algerian Sahara Academic research paper on "Agriculture, forestry, and fisheries"

CC BY-NC-ND
0
0
Share paper
Academic journal
Energy Procedia
OECD Field of science
Keywords
The Algerian Sahara / groundwater resource / flow / Foggara / drip / pivot.

Abstract of research paper on Agriculture, forestry, and fisheries, author of scientific article — Mohammed Amine Kendouci, Ali Bendida, Rachid Khelfaoui, Benali Kharroubi

Abstract The Algerian Sahara contains important potential underground water. These resources, which would be 5 billion cubic meters, of which 1 billion cubic meters is mobilized, and are therefore non-renewable fossil fuels. The availability of water led to the development of agriculture in the oases adapted, this oasis agriculture is characterized by small family farms in which agricultural production is organized according to a scheme that meets the needs of consumption (vegetable production for family needs) and marketing (usually some vegetables, but mostly dates) Foggara is the main component in the traditional catchment supply and distribution of groundwater wells irrigation.des, galleries, combs distributors of water, seguias, seguias of secondary and small basins (madjen) built the system. Foggara waters are currently intended for irrigation in most Ksour. The vegetable production is structured vertically in a palm plantation of more than one score of years, under the date palm of the fruit trees (fig tree, olive-tree, vine, pomegranate) are planted. The oases are generally installed in alluvial zones drained by rivers and in the low parts are periodically flooded. It is very important to see the impact of the old system of irrigation “Foggara” and recent “drip, pivot” on the environment; Or impact: On the groundwater resources On the ground And on agricultural output

Academic research paper on topic "The Impact of Traditional Irrigation (Foggara) and Modern (drip, pivot) on the Resource Non-Renewable Groundwater in the Algerian Sahara"

Available online at www.sciencedirect.com

ScienceDirect

Energy Procedía 36 (2013) 154- 162

The impact of traditional irrigation (Foggara) and modern (drip, pivot) on the resource non-renewable groundwater in

the Algerian Sahara

Mohammed Amine Kendoucia,b a*, Ali Bendidaa, Rachid Khelfaouib and Benali

Kharroubia

a Laboratory of Hydrology and management of Water resources (HYDRE), University of sciences and technology, Oran, Algeria. b Laboratoire d'Energétique en zones arides université de Bechar, Algérie.

Abstract

The Algerian Sahara contains important potential underground water. These resources, which would be 5 billion cubic meters, of which 1 billion cubic meters is mobilized, and are therefore non-renewable fossil fuels. The availability of water led to the development of agriculture in the oases adapted, this oasis agriculture is characterized by small family farms in which agricultural production is organized according to a scheme that meets the needs of consumption (vegetable production for family needs) and marketing (usually some vegetables, but mostly dates).

Foggara is the main component in the traditional catchment supply and distribution of groundwater wells irrigation.des, galleries, combs distributors of water, seguias, seguias of secondary and small basins (madjen) built the system. Foggara waters are currently intended for irrigation in most Ksour.

The vegetable production is structured vertically in a palm plantation of more than one score of years, under the date palm of the fruit trees (fig tree, olive-tree, vine, pomegranate) are planted. The oases are generally installed in alluvial zones drained by rivers and in the low parts are periodically flooded.

It is very important to see the impact of the old system of irrigation " Foggara" and recent "drip, pivot" on the environment; Or impact:

- On the groundwater resources

- On the ground

- And on agricultural output

Keywords: The Algerian Sahara, groundwater resource, flow, Foggara, drip, pivot.

* Corresponding author. Tel.: +213790594126; fax:+213-764937. E-mail address: amine.ken37@yahoo.fr.

1876-6102 © 2013 The Authors. Published by Elsevier Ltd.

Selection and/or peer-review under responsibility of the TerraGreen Academy

doi:10.1016/j.egypro.2013.07.018

1. Introduction

Exit of the administrative cutting of 1974, state of Adrar extends on the Northern part of the Algerian Western South, thus covering a surface of 427.968 km2 is 17,97% of the national territory. From a geographical point of view state of Adrar includes three areas which are Gourrara (Timimoun) Touat (Adrar) and Tidikelt (Aoulef).

Zone with agricultural hydro vocation, state of Adrar conceals potentialities which may undergo beneficiation in the field of agriculture.

The oases of this zone of study are distinguished from the other oases of the country by a water delivery system dug in hydrogeology formations of the continental guide [1].

This immense water reserve occupies almost the totality of the septentrional Sahara and it is thanks to the creation of this clever system, it "Foggara", that a chain of oasis allowed, during centuries, the development of an agriculture of subsistence and the maintenance of the populations in hard and rather hostile desert spaces.

2. Data of the physical environment

2.1. Geology

It is a lengthened area, directed Northern limited to the East by the plate of Tademai't, at north by the great Western erg in the west by the Erg Echech in the south by the plate of Tanezrouft, locates on the Western southern edge of the vast secondary basin, extends from the Saharan Atlas in Hamada of Tinhert and of Touat Gourara to the Golf of Gabes of Tidikelt in Gourara the grounds of this unit level sandy formations of the Continental Guide (Gault) or marine formations of the higher cretaceous or grounds me continental Pliocene's [3].

2.2. Hydrogeology

The septentrional Sahara contains a large sedimentary basin of Mesozoic age said the Continental Guide (Gault) constituting an immense unit hydrogeology with a surface of 780.000 km2. The southernmost dorsal of Me zab divides the basin into two pennies basins:

Under Eastern basin with a surface of 500.000 km2, occupies in its great part by the Erg Eastern and drains towards north.

The desert formations of continental the guides rest in angular unconformity on a primary education substratum of age which levels in the depression of the valley of Saoura (Messaoud Wadi) in the west. In the east, they are covered by formations argil gypsies with the transgression of the cenomanien overcome by a calcareous plate with Turonien and senonien [3].

Constitution of the Continental Guide:

The Continental Guide east constitutes continental deposits, sandy clays, clays and likings. It is a multi-layer system which extends on a surface of about 780.000 km2, its total tank (in theory) is regard 6.103 m3 is a fictitious flow of 1000 m3/s during 2.000 years (UNESCO 1970). - Useful output of the reserve of Ci

The thickness of the formation of the continental guide varies north towards the south and from the east towards the west, according to the data of drillings major sowings. Its thickness is about 150 to 400

meters. Noting, that the thickness decreases gradually by the east towards, the west and north towards the south and fails in bevel on the substratum of the primary education. - Static Level of the water table of Ci:

The static level of the water table of Ci oscillates between 13 and 30 m compared to the surface of the

ground and can reach 100 m on the level of the plate of Tadmait (drilling of Ain Belbel).

Direction of water run-off of the tablecloth:

The axes of water run-off of the water table of Ci are generally:

■ North-South.

■ North is.

■ Western south.

Food of the aquifer us system of Ci: The contributions of the aquifer us systems of Ci are carried out according to various manners:

■ Infiltration of surface waters on relief to the edges of the basin.

■ Direct infiltrations of water of precipitations.

2.3. Vegetation

The vegetation of this area, except perimeters irrigate, is extremely reduced, following the very severe climatic conditions. On the plates and the terraces of erosion (zones of Foggara) it is practically nonexistent except in some rivers or ravines of streaming has wind filling or eocolluvial, or is some palm trees sometimes some tamarix (mainly with the limit of the terraces of erosion).

In the zone of sandy accumulation corresponding to the rupture of the slopes between the terraces of erosion and the sebkha, (zones of palm plantations) the vegetation relatively more abundant, is made of palm trees more or less disperse remaining without irrigation; thanks to the low depth of the tablecloth in this zone (often < 2m) and a major rooting, one finds also some plants fixing of sand, formant of small sandy hillocks called << Agaia >> and << Salsola >> [2].

3. Methods of irrigation

3.1. Foggara

The traditional system of irrigation "Foggara" in the Sahara Algerian, allowed the passage of the nomadism the sedentarisation. This hydraulic organization made it possible to install and maintain here oases, whose crucial role was to offer to the travellers and to the caravans the ultimate stage before the crossing of large the south. The ingeniousness of the process lies in its design and its adaptation to the climate and living conditions Saharan: it removed the exhausting water drudgeries, which took the essence of the time of the inhabitants, ensured a provisioning constant flow, without risk to dry up the sheet of water and by limiting evaporation at least.

3.1.1. History

Foggara is a system of horizontal collecting of subterranean water. It is of Persian origin according to which, where the oasis of Irbil seems to be the first, at the end it VII century to use this technique, it is to

propagate then in India and China; and in North Africa, it was introduced by the Moslems almoravides during X and XI century.

In Algeria, Foggara it developed in the south-western areas of the country in particular with the areas of Adrar, Touat and Gourara where hydrogeology and topographic conditions of its areas consists of a chain of sebkha, supplied with executor naturalness of the tablecloth of the continental guide leveling on the surface of the ground [2] [3].

This system of collecting by drainage galleries is known a little everywhere in the world under several names:

In Iran, in Yemen, and in Jordan: "Qanat".

In Italy: "Ingruttati".

In Spain: "Madjirat".

In Oman Sultanate: "Falag".

In Morocco: "Khattara".

In Japan: "Manbo".

In Latin America: "Hoyas".

In China: "Jingquen".

In Algeria: "Foggara".

In Tunisia: "Ain or Mkoula".

3.1.2. Definition of Foggara

Foggara is an underground drain dug in the zone of the natural discharge system of the tablecloth of the continental guide; it consists of several successive wells communicating variable depths, joined together at the base by a drainage gallery usually called "ennfad". The water mobilized by the drains which follow a light slope is drained thereafter by secondary irrigation channels to irrigate the palm plantations.

The distance respected between two Foggara does not have to be lower than two approximately hundred meters on ground. The wells are separate one of the other from six to twelve meters and even more, one Foggara can reach 500 to 600 wells, its length varies from 1 to 15 km, the distance between the wells is not inevitably respected.

Fig.1: Outline of the Foggara principle

Fig.2: Vertical section along the Foggara.

The wells were create initially to evacuate spoil during work of execution of the gallery, and were used thereafter in work known as maintenance, this on the one hand; on the other hand these wells are points of ventilation for Foggara.

The vocabulary of Foggara:

Ennfad: gallery drainage connecting the line of well.

Hassi: visible well surfaces some by the cut heaps which mark out it

Aghessro: the part covered with flagstone of likings when the gallery emerges with the free air. Medjra: when it leaves this protection

Kasria: the stone punt bored of gauged arch which orders the distribution of water Irrigation channels: small channels on the outlet side of the distributer, or water is led in the pieces. Madjen: very flat clay basin compacted in the capacity approximately equivalent to the volume of water delivered in24 hours Guemoun: compartmental unit

The causes of the drying up of Foggara:

The causes of drying up of Foggara are of three types. The problems involved in Foggara:

- The rate of losses of the water drained by infiltration.

- Routine Lack of maintenance.

- The position of the gallery drainage compared to the direction of flow of the tablecloth.

The problems involved in the nature of the drained sheet of water, the low flow which can characterize the majority of primarily Foggara cost to the not very permeable nature of the tank. Problems involved in the exploitation of drillings:

The permanent exploitation of water drillings influences the aggregate rate drained by Foggara and can lead to the total drying up of this system of collecting.

3.2. Irrigation by pivot

The irrigation by pivots is an imported American technique, which was established in several Arab countries touched by the desert fact.

The irrigation by pivot is a system of watering which consists in distributing water in the form of rains on ground; very employed for a long time by the gardeners, the horticulturists and arboricultures for the cultures. Market-gardening, floral, shrubby, fruit-bearing, the lawns, sprinkling tends, considering the large advantages which it has and which we further enumerate, with being used more and more in field

In all the old methods water is distributed with more or less uniformity on the ground by drains and it penetrates there under conditions more or less favorable according to its regularity and its slope, into the system pivot water fall naturally on the ground, therefore under the same conditions as atmospheric precipitations, and infiltrates there, taking into account only the permeability of the ground. The operation of the system pivot; this mode rests on a drilling, to which corresponds a tripod and a mechanical arm variable length (being able to reach 500m), which turns night and day slowly and can sprinkle with a blow 30 to 50 hectares this technique requires important investments, drilling, material, assembly and maintenance.

Fig 3 : irrigation by drop

We quote that the simple processes or sprinkling is done with the watering-can or water cart, we will examine the modern processes which use:

1. An apparatus of pumping which provides water necessary to watering.

2. Pressure lines which distribute water in touts the points useful of surface to be sprinkled and which supply the apparatuses of distributions.

3. Apparatuses which project and distribute water on ground.

These installations are fixed, mobile or mixed, they are known as fixed when the pumping station and the network of drains are placed in a permanent way, they make it possible to remove most of the labor of operation, but the formation expenses are very high and they are known as mobile when the unit can move at will, one fall then into opposite excess; one does not make any more economy of labor, reason to the difficulty of transported the material at will what allows are use with full output during all the period with watering, from where a better damping.

Finally one can design mixed installations including/understanding of the permanent principal drains or even channels, in this last case one moves along the channels a simple motor-driven pump group with jet which sprinkles the cultures this proceeds tends more and more to develop in the areas or water was brought by channels and was distributed then by the drains.

3.3. Irrigation by drip

The microphone-irrigation, also known under the name of "drop by drop", is a method of irrigation used in arid region because it to the minimum reduces the use of water and manure. Water drains slowly towards the roots of the plants either while running on the surface of the ground or by directly irrigating the rhizosphere by a system of pipes.

This technique is the most important innovation in agriculture since the invention of the aspersers in the years 1930, which had already replaced at the time an irrigation requiring too much of water. The system drop by drop with low pressure is a vital in the arid regions and semi-arid need

The irrigation is an artificial water contribution to crop plants, the purpose of which is to compensate for the insufficiency of natural precipitations and to allow the harmonious development of these plants. There are two great kinds of irrigation: the irrigation of surface and the irrigation under pressure. The latter represents two types, the first is the irrigation by sprinkling, the second is the localized irrigation of which the drip. The drip is a form of the located irrigation, so called "micro-irrigation". It consists in sprinkling only one fraction of the ground, and does not wet the foliage, by using low water flows with low pressures.

Fig 4 : irrigation by drip

Water forms, under surface, a wet "bulb", which maintains dry most of surface. Evaporation is considerably braked, as well as the lifting the adventitious ones. One can say that water does not sprinkle the ground, but the plant; it "is directly returned roots".

One measures all the economy which results from it, in all the hot countries, compared to the gravitating irrigation. But keep we to condemn this one: the percolation is often imperative under hot climate, like the case of several areas of Algeria and in particular the high plateaus and the Sahara

Advantages of drip

1- It distribution in the field is uniform

2-application of manure can be done easily by resourcefulness 'irrigation directly on the level of the roots

3-Water is brought directly to the place necessary, on the level of the roots

4-The quantity and the duration of the irrigation are highly controlled in order to maintain the ventilation and the moisture of the ground on their optimum level

5- System effectiveness for the use of water is higher than the other methods by far

6- Saving in labor, a person is necessary to sprinkle all the piece, only one gesture (the opening of the valve) replaces hours of going and come.

7- Facility of use and maintenance. It does not require any preliminary experiment as regards irrigation and can be operated by any family member

Disadvantages:

1-High cost of the investments

2-Professional, continuous and meticulous maintenance Subheadings should appear in boldface.

4. Conclusion and recommendations

To become palm plantations in the state of Adrar is primarily related to the good performance of the traditional system of irrigation which is it "Foggara". This being, any drying up is likely to generate the total deterioration of the palm plantation resulting in a projection of the sebkha and the total abandonment of the pieces.

The example of the area of Tamest reflects the actual position of Foggara, and makes it possible to determine the causes of the drying up of Foggara whose, the rate of losses by percolation in the inactive part of Foggara, the lack of maintenance (clearing out) and the problems involved in the exploitation of water drillings.

On the basis of element developed above it can be proposed the following recommendations: In order to be able to rehabilitate in a durable way Foggara them it takes place there of:

• To reorganize the field of collecting by the correction of the flows of drillings which will make it possible to reduce the reciprocal interference between the various works of collecting.

• To carry out the extension of the drainage gallery to reduce the influence of the drilling in way this is parallel within the meaning of flow of the sheet of water.

• To make impermeable the inactive parts of Foggara to eliminate the losses by percolation.

• To rehabilitate the traditional network of irrigation (Majen and irrigation channel) to reduce to the maximum the water losses per evaporation and infiltration.

• The rehabilitation of Foggara must be strongly constant, to bring an added-value to the economy of the area and this by a growth of the agricultural productions and a promotion of eco-tourism

The vegetable production is structured vertically in a palm plantation of more than one score of years; under the date palm of the fruit trees (fig tree, olive-tree, vine, and pomegranate) are planted. The oases are generally installed in alluvial zones drained by rivers and in the low parts are periodically flooded.

It is very important to see the impact of the old system of irrigation "Foggara" and recent "drop by drop, pivot" on the environment; That is to say impact:

- On the underground water ressources

- on the grounds

- And on the agricultural output

Acknowledgements

The authors would like to express their gratitude to the MESRS of Algeria, for the support.

References

[1] Bellil (R.), "Migration And Evolution Of Two Ksour: Of Gourara, Has Saïd And Timimoune".C.N.R.P.A.H. April 1992

[2] Bellil (R.), "Ksour and saints of Gourara, in the oral tradition, local hagiography and chronicles. Memories of the anthropological and historical prehistoric research national center". C.N.R.P.A.H. serial N°03, 2003.

[3] ANRH 2003, "Study of the drying up of foggaras in the wilaya of Adrar 2003", ANRH of the wilaya of Adrar ,2003

[4] Khettara : http://jorf.sagya.org/english/thekhettara.htm

[5]Khettara : www.jorf.sagya.org/photos/khettara.