Scholarly article on topic 'The Future of the Ksar in Sustainable Development'

The Future of the Ksar in Sustainable Development Academic research paper on "Earth and related environmental sciences"

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{"Solar Energie" / Ksar / Foggara / "Gourara-Algerian Sahara" / "Sustainable Development"}

Abstract of research paper on Earth and related environmental sciences, author of scientific article — Ratiba Wided Biara, Abdelmadjid Hamouine, Mohamed Nabou

Abstract The Algerian Sahara is a huge area, on which scattered oases where life is possible are grafted, as a consequence of water presence. These oases compile homes through a rich architecture; this has become a vernacular heritage, which unfortunately is at risk of extinction. Therefore the protection of this heritage goes exordium by seeking a balance between preserving the historical and cultural identity, but especially by the improvement of living conditions of the people who inhabit it. Indeed the life standard in these regions is inadequate, hence many villages scattered across the Sahara are dependent on electricity supply from the north. The latter constitutes major disarray, because of the low housing density, the fundamental mismatch of tissues, and their situations at the expense of depression. Consequently, the electrification of houses and infrastructure is quite difficult, fairly expensive, and sometimes virtually impossible. On the other hand, the inhabitants of the Saharan oasis have implemented ingenious techniques for survival in their harsh environment. But today, their productive activities are facing the increasingly weakening water resources in their area, and the difficulty to dispose of these resources. However, the control of the water is the subject of permanent struggles through archaic practices which can’t adapt to the requirements of modern life. This imposes the need for more efficient tools, for the keeping of the tribes which are likely to leave the region, while looking for a more convenient living environment. It is now appropriate to introduce renewable energy that is able to contribute in solving many problems in the regions of south Algeria, where all conditions for using solar energy are available. The use of renewable energy in southern Algeria should be a strategy for the development of the local inhabitant's life.This will integrate them into their surrounding contexts in order to stabilize them, namely to safeguard the vernacular heritage in transmitting collective memory.

Academic research paper on topic "The Future of the Ksar in Sustainable Development"

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Energy Procedía 18 (2012) 35 - 42

The future of the ksar in sustainable development

BIARA Ratiba Wideda, HAMOUINE Abdelmadjidb, NABOU Mohamedc

aLecturer, Bechar University, Bechar 08000, Algeria bProfessor, Bechar University, Bechar 08000, Algeria cLecturer, Bechar University, Bechar 08000, Algeria

Abstract

The Algerian Sahara is a huge area, on which scattered oases where life is possible are grafted, as a consequence of water presence. These oases compile homes through a rich architecture; this has become a vernacular heritage, which unfortunately is at risk of extinction. Therefore the protection of this heritage goes exordium by seeking a balance between preserving the historical and cultural identity, but especially by the improvement of living conditions of the people who inhabit it. Indeed the life standard in these regions is inadequate, hence many villages scattered across the Sahara are dependent on electricity supply from the north. The latter constitutes major disarray, because of the low housing density, the fundamental mismatch of tissues, and their situations at the expense of depression. Consequently, the electrification of houses and infrastructure is quite difficult, fairly expensive, and sometimes virtually impossible. On the other hand, the inhabitants of the Saharan oasis have implemented ingenious techniques for survival in their harsh environment. But today, their productive activities are facing the increasingly weakening water resources in their area, and the difficulty to dispose of these resources.

However, the control of the water is the subject of permanent struggles through archaic practices, which can't adapt to the requirements of modern life. This imposes the need for more efficient tools, for the keeping of the tribes which are likely to leave the region, while looking for a more convenient living environment.

It is now appropriate to introduce renewable energy that is able to contribute in solving many problems in the regions of south Algeria, where all conditions for using solar energy are available. The use of renewable energy in southern Algeria should be a strategy for the development of the local inhabitant's life. This will integrate them into their surrounding contexts in order to stabilize them, namely to safeguard the vernacular heritage in transmitting collective memory.

© 2012 Published by Elsevier Ltd. Selection and/or peer review under responsibility oí The TerraGreen Society. Keywords: Solar Energie, Ksar, Foggara, Gourara-Algerian Sahara, Sustainable Development

* Biara Ratiba Wided. Tel.: +213-792-21-36-15; fax: +0-000-000-0000 . E-mail address: townscape11@yahoo.fr.

1876-6102 © 2012 Published by Elsevier Ltd. Selection and/or peer review under responsibility of The TerraGreen Society. doi:10.1016/j.egypro.2012.05.015

Introduction:

A part of the Algerian Sahara is divided, if not by nature itself, then by men, in three parts: Gourara, Touat, and Tidikelt. In this regional group, the man sought forms, according to his culture, and built works: Aghem (House) and the foggara, which enabled him a life in this area. The shape that emerged allowed adaptation to a hostile environment and most importantly, the domestication of a territory. Therefore, to survive in this harsh environment, the oases farmers have developed distinguished methods that get used to the local conditions. These are the foggaras, subject of permanent struggles, which have done this prodigy to guarantee life in this desert region, face of a very fleeting rainfall, high temperatures, high winds, and of perpetual burial.

The presence of water has extensively justified implantation of vernacular establishments and the attitudes of men for its exploitation, through a system which up to now governs society. Unfortunately, human activity today faces the difficulty to dispose of these water resources. And it is because the survival of the foggara (a system which contains an art, a symbol, a technique, and rules on water resources) is decreasing, that we are witnessing the decadence of many oasis. Therefore, a temporary situation in the Gourara can be assumed; even a final desertification of the area can be feared of.

These are the causes, which open up perspectives on the use of solar energy, in profusion in these regions as substitution to electricity, hardly gained. It will promote the effectiveness of the use of water in order to safeguard this ancient monument, subsequently to retain the inhabitants of the oases, witnesses of a collective memory.

The methodology adopted to achieve this objective, is done first through the understanding of the mentioned system. Then, the deficiencies it presents, and what role can solar energy play to save it. Finally, a method of calculation for solar pumping is presented.

1. Hydraulic trial in Sahara

Low potential

precipitation evaporation

very low underground flow

Facing Severe climate constraints, intrinsic to these regions (one of the driest lands in the world [1]), defined by overriding evaporation, and the scarcity of flows on the surface (see figurel); only specific structures, able to withstand these conditions, can promote agrarian production: It is to collect at best, the rare water and difficult to achieve, through efficient and important developments.

These developments are based on a new technique, that of the foggara, which drains ground water to the surface by gravity. Realizing a slope between the two extreme points, for the movement of water [2]

Fig. 1 Saharan hydropower scheme

The foggaras in this region are developing groundwater of Gourara, which feeds water to origin of "the Saharan Atlas", a set designated by "water of the Erg" [3]. Therefore, to use effectively the water table, we need to dig galleries "the foggaras.

2. Principle of the foggara:

"A foggara is a gallery which brings the waters underground for irrigation with an appropriate slope field, thus watering is provided by simple gravity, hence the interest of the foggara.» [4]. The important part of the device is that which enters the water, see figure 2.

Fig.2 flowsheet of a foggara, from A.Cornet

The foggara water flows constantly, but with a variable rate, moreover it is in continuous decline. Indeed, the drainage by sections prelude of the foggara, creates a drawdown of water. At this time, it must extend the foggara upstream, to resurrect the first flow. However, in all cases, the rate of water flow is not fast, it leads, therefore, sand deported by the wind, as well as from talus of the walls, what makes the foggara unusable, unless there is annual curages.

Moreover, the principle of irrigation requires that the slope of the land is lower than that of the mouth of the foggara, where the direction of the foggara is dependent on topography. That illuminates the situations and developments of the foggara oasis depending on depression.

Indeed, to explore the mapping to the methods of irrigation adopted in the Gourara, it turns out that for most, oasis of foggaras are along topographic accidents. Except that at the time, many are those with Wells to pendulum.

3. Constraints of the Use and the governance of foggara

3.1. Know-how for the preservation of the oasis: social approach

Following the deficiencies, and the decadence of the foggaras system, the oasiens acted to persist in their region as follows:

When oasis was steep, they were performing a shift in the gardens to the bottom of slope, to moderate the lowering of the water. When this was not possible, the farmers need to develop a slope excavating deep trenches, the water which emanated, stood by pendulum. If this was not possible, the foggara was dropped altogether in favour of wells to pendulum. But in all cases, the physical effort was intense.

Build, use, and maintain the foggara in our days, becomes a tedious mission, given the difficulty of the flushing system, which apostrophe specialized workforce, under condition that they agrees is to work in difficult situations.

On the other hand, the burial, the lack of maintenance and over-exploitation of the foggara during a resulted time interval, provoke the regression of the number of foggaras, the weakness of the flow to the drawdown of the water, as well as the degradation of many of the foggaras.

Moreover, it is noted that a non-negligible amount of drained water is lost by infiltration along the inactive Gallery and its length, but also by the phenomenon of evaporation.

In addition, the more that the population believes, the more urban flourishes, and the more water demand is rising; the traditional method of catchment is no longer able to meet current needs, which are already very important. From this, we need to appeal for modern tools, to promote the system, especially when the water reserves are correspondingly substantial.

3.2. The use of energy for sustainability of the process of irrigation:

• Deficiencies in the areas of the south of Algeria:

Electricity: The cities of the Algerian South have large surfaces, whereas their population density is quite low. Adding to this, the disparity of intrinsic tissue and their isolation of the regions of the North; makes their governmental economic support, a burden, especially in electrical energy.

Electrification is passed in through generators [5]. They consume a very expensive quantity of fuel -that is if one can buy it at all. Notwithstanding, this network has disadvantages and significant limits: frequent cuts (during periods of heat wave), prejudicial to the harvest which requires regular irrigation.

The exploitation of groundwater: The water consumption in the ksour, increases in issue of irrigation of big areas of palm groves and gardens. At the same time, the use of traditional tools through foggara, surpasses the capacity of farmers, being very deep aquifers and require regular maintenance.

• The solar energy as solution

If the water is the source of life, the improvement of living conditions in desert and arid zones, is certainly bound for appropriate solutions to the problem of water deficit. It is therefore, in urgent to maintain supply for isolated Saharan regions where living conditions are very harsh.

Since, especially, solar energy is in abundance in these areas, and free, (they generally profit from an exceptional radiation; the average annual duration of sunshine is 300 days. The annual average of overall horizontal received sunning per day ranges from 4.5 to 7.5kWh/m2/d [6]); what makes a technology suitable for drinking water supply equipment. Solar pumping systems are an ideal solution for water supply, and especially where the electricity is absent. They offer technical solutions for domestic needs, the supply of drinking water, livestock, or irrigation

• The use of solar energy for pumping water/Photovoltaic technology achieved the reliability to meet

energy demand.

• Drilling wells in shallow depths downstream from the Gallery will increase by inputs of water flow of the foggara, if provided with solar pumps.

• Mechanize curages systems to deport the sand particles.

• Equip wells pumps to correct the deficit of the foggaras flows, preferentially photovoltaic.

Commonly used, the concept of well-being is closely linked to that of the quality of life. It must be taken into account by professionals, to ensure an attractive, safe and convenient environment.

4. Operation of photovoltaic pumping system

Pumping systems generally consist of:

• Photovoltaic generator, composed of electrically interconnected modules up to be a production DC unit, mechanical support structure

• Power Conditioning consists of a DC/AC converter, able to vary the power available in the generator output voltage, and frequency

• An immersed pump group, consisting of the association of an electric motor of induction and a pump

• A wiring through which runs the energy from the generator to the engine

• Hydraulic infrastructure which leads water from the source to distribution points

• A drinking water system, if necessary.

4.1. Architecture of the systems

An example of a photovoltaic system is given in the following figure.

Chain of information

Solar energy

Communicate

Microprocessor

Cables

Solar panel

Distribute

Convert

Convert

UPS power

Centrifugal Pump

Chain of energy

Fig.3: Architecture of the string to extract water from a solar panel

4.2. Solar sizing

It is necessary, even before the installation of solar panels, to know the available solar energy (average daily monthly values of solar radiation), water requirements (water quantity really consumed), and the height of pumping, and calculate the required hydraulic energy.

• Estimation of water needs

Water in such regions are valued at 20 liters per person and 30 liters per head of livestock [7]. While the needs of water for irrigation of the gardens and palm groves, depend on temperature, the humidity of the violence of the winds, as well as the method of irrigation.

• Method of calculation of the hydraulic energy

Mean daily and monthly necessary hydraulic energy is calculated from the following relationship:

Eh = g pa Va h / 3600

Knowing that: Eh : hydraulic energy (Wh/day) g : acceleration due to gravity (9,81m/s2) pa : density of water (1000 kg/m3) Va : volume of water (m3/day) h : total height (m)

• Size of the photovoltaic generator

The output power of a photovoltaic generator under standard conditions of measuring is calculated on the basis of the following formula:

Pp = ^g A Gce

Pp : output power under the standard conditions of measuring (W)

"Hg : performance of the generator to the reference temperature (25 °C) [8]

A : active surface of the generator (m2)

Gce : light in the CSM (1000 W/m2) [2]

The daily electric energy, Ee, is given by:

Ee = ^PV A Gdm (P) Where

Gdm (P) : daily average radiation incident on the plan of the modules to tilt P (kWh/m2/day). ^PV : daily average efficiency of the generator in operating conditions -qPV = Fm 1 —j Tc — Tc, ref^g

with Fm: coupling factor, defined as the ratio of the electrical energy generated under the conditions of exploitation, and electrical energy which generates if the system is working at maximum power. j : temperature coefficient of cell. y takes values between 0,004 et 0.005 /°C for the modules mono and polycrystalline silicon, and between 0.001 and 0.002 for amorphous silicon modules. Tc : daily average temperature of cells during the hours of sunshine.

The relationship between the necessary electrical and hydraulic energy is defined by the expression: E e= Eh ц MP

Eh : monthly average hydropower (kWh)

^MB : performance of the subsystem engine-pump.

Photovoltaic modules must be in agreement with the international standard IEC-61215

• Design of the pump

Flow peak Q (m3/h) is calculated by the relationship:

Q = 3.6 Ph

Ph : hydraulic power required (W), Ph = Pe ^MB (^MB : (crest of the motor-pump subsystem performance).

g : acceleration due to gravity (9.81m/s2) h : total manometric height (m)

• Diameter of the pipes

The diameter of the piping of pumping can be obtained by the formula of Bresse [9] :

D = K Q

D : diameter of the pipe (m) K : coefficient that varies from 0,75 a 1,40 Q : flow pump Ridge (m3/s),

n D2 4

Q=- v, avec v =-

4 n K2

• The effectiveness of the system

The effectiveness of the water supply system is to be assessed by the following criteria:

• Pumping capacity

• Reliability

• Security

• Simplicity in use

• Simplicity in installation and maintenance

• Sanitary water quality

Conclusion

Saharan men, stick to their territory despite the hard conditions, using archaic figures to sustain these arid regions in water. These long galleries require a perpetual care and persistent (curages regular and laborious), more obscure any hydraulic performance, and adhere to growing losses of water it transships. Added to this, the permeability of the foggara concedes the filtration of water, which can receive a second smaller network than the primary one.

In addition, the gradual drawdown of the water, due to the evolution of the hydraulic system of the foggaras in the reduction of the supply of water in the Erg, most often associated with their burial, explains the urgency of intervention for the safeguarding of this centuries-old monument, as it is of course the condition sine qua non of their survival, but mainly because the will of the Saharan to continue to live in their village of origin. (The authentic rural life persists in the Algerian Sahara, life in the ksour is to confirm). These treasures of ingenuity have developed humanity for centuries, this is hard to remain in the ksour of origin and deserves to be supported, to the bias of the introduction of photovoltaic energy for such potential of perimeters of agriculture irrigation, especially since this technique is promising for sustainable development.

These are tools that concede the economy of time and the efforts of men are who are still fighting. Subsequently, this study has shown that it is in the emergency, to appeal to the solar energy photovoltaic pumping in these arid regions. To make it, the actual needs in water must be identified, and determine the necessary hydraulic energy according to the method established in this study

Subsequently, this study has shown that it is in the emergency, to appeal to the solar energy photovoltaic pumping in these arid regions. To make it, the actual needs in water must be identified, and determine the necessary hydraulic energy according to the method established in this study

References

[1] Guillermou Y. Survie et ordre social au Sahara : les oasis du Touat-Gourara-Tidikelt en Algérie, Cahiers des Sciences Humaines, Editions du CNRS, Vol. 29, n° 1, pp123-128. Paris; 1993

[2] Grandguillaume G. Régime économique et structure du pouvoir : le système des foggaras du Touat. In: Revue de l'Occident musulman et de la Méditerranée 1973 ; volume 13 n° 13-14 : 438.

[3] Cornet A. Essai sur l'hydrologie du grand Erg occidental et des régions limitrophes:les foggaras. travaux.I.R.S. 8;1952, pp 71-122. T.VIII

[4] Bisson J. Le Gourara. Étude de géographie humaine. Alger.Imprimerie Imbert; 1957.

[5]Bouzid. B. l'energie solaire et les régions sahariennes-exemple de la région d'Adrar, (Laboratoire d'Energie Photovoltaïque, Centre de Développement des Energies Renouvelables), Rev. Energ. Ren : Valorisation, pp101-102; 1999.

[6] A.A.M. Sayigh, 'Solar Energy Activities in the Arab Countries', Congress of Int. Solar Energy Society, pp. 1851 - 1865, Sep. 1989.

[7] Thomas M.G. Water Pumping.- The Solar Alternative, Photovoltaic Design Assistance Center, Sandia National Laboratories, NM 8718 5, Albuquerque, 58 p; 1987.

[8] Handbook on Solar Water Pumping", Intermediate Technology Power & Partners,Reading, 124 p., 1984.

[9] Silvestre P.,Fundamentos de Hidráulica General, Limusa, Mexico, 381 p; 1983.