Management and valorization of Water Resource in Arid Regions

The main source of drinking water supply for residents of Algerian arid regions consists of groundwater, represented by Terminal Complex aquifer (TC) and the continental intercalary (IC). The resource available is estimated at 5 billion m3 / year (CT). Given the conditions of the climate, arid or even hyper-arid , these formations are poorly fed, the charging system is about 1 billion m3 / year in total. It is especially in character of fossil resources, costly for mobilization and difficult of use.

In addition, the heavy exploitation of these aquifers by about 8800 Well drilling by the three border countries, that this resource is facing a number of major hazards : strong interference between countries ,disappearance of artesianism, depletion of natural outlets , excessive growth of the deep drilling, water salinization (SASS, 2000)

On the other hand, the salinity of aquifers water of the northern Sahara reflects the effect of the slow groundwater favoring ionic exchange between water and host rock, and the effect of the strong localized exploitations which resulted in leakage between the different aquifer levels. Ion exchange is clearly manifested in the TC aquifers in which water salinity accuses an increase from the edges of the basin to the outlets. The leakage effect is more highlighted (within TC), particularly in areas of intensive farming close the Algerian-Tunisian chotts.

According to the research works that the water division is conducted on the water quality of northern Sahara, the CT aquifer water present two facies depending the way of the calcium-chloride-sulfated flow chlorinated-sodium with a total hardness exceeding drinking standards. These waters are highly mineralized concentrations vary between 2g / l and 8g /l in the region chotts, added to the presence in excessive quantities of fluoride. Despite efforts in the field of drinking water and sanitation in the Saharan regions, the population still uses the tanker truck distributing a water softer appearance but presents a risk in terms of health especially in summer.
For that we can guarantee to users a consumption of water in sufficient quantity and quality satisfying three conditions are necessary :

1. The sustainability of source supply
2. Monitoring on the permanent environment health thanks to of an adequate water treatment system and environmental sanitation.
3. Concretization the application of hygienic rules relating to the transportation, storage and sampling drinking water.

The waters of the Continental Intercalary, fled into the deeper layers of the Albian are characterized by a temperature gradient (55 ° C to 65 ° C), an oscillating excessive hardness between 59 and 89 ° F and moderate mineralization reaching 2g / l. This water causes a precipitation of tartar and alteration canalization .This situation generates a huge losses in time and money and creates inconvenience to farmers.

Water demand is increasing rapidly due to population growth, urbanization, industrialization and the needs for irrigation. The Production of urban wastewater is estimated at about 500 million m3 / year. As for the drinking water supply almost all of the agglomerated population (urban and rural) is connected to the public sanitation network, the population rate agglomerated connected to the sanitation network was in 1996 was 85%. If there is some improvement of the living environment in urban areas, unfortunately the discharges of wastewater into the oueds are in clear proliferation. This is what constitutes a threat for the quality of water resources (MATE 2000) , health and environmental risks. About Fifty water sewage treatment are carried out through the country and about ten under way.

Moreover, according to the Directorate General of Civil Protection estimated in a report on flood risks that " there is no protected areas against this risk and that these events are unpredictable in time and space. "If some areas like Algiers or the East of country are most concerned, all the territory may be sensitive to this kind of natural disasters . The problem of flooding is a "priority" for the Algerian government. Indeed, the threat of new flooding increases with global warming including in arid regions (extremes phenomenon).

The floods are the result of a cross between two factors: the hazard considered as hydrological result and vulnerability is due to human action. The phenomenon of deforestation in Algeria as a result of this human intervention in the environment for obvious reasons of land use by urbanization, added others factors such as the occupation of oueds beds , failure of stormwater collection networks. The result of the combined effect of all these events is that 40 to 50% of communes in Algeria, those of the South included, incur the flooding risk . 23 of them are considered catastrophic, according to (Mr. Bahlouli, ANRH) which advocates the realization of a warning strategy and risk forecasts, through the collection and use of the considered information.

Strategic thrust : Optimizing the use of water resources and prevention of water-related risks

Research topics :

• Improving the quality of drinking water of southern Algeria
• treatment of scaling waters of the Albian aquifer
• Natural treatment of urban sewage
• Flood management in arid regions

objectives:

• Responding to the urgent need of the population of southern regions with drinking water of satisfactory quality, remove excess salts such as chlorides and sulfates.
• Remedy the problem of scaling waters of the Albian to achieve better socio-economic exploitation.
• Perform to experimentation lagoons to a small scale in sensitive areas of the valley of oued Righ.
• Perform the establishment of flood zones cards

Expected results :

• Process for treatment to have a drinking water without cause another type of pollution or other risks.
• Valorization of geothermal water and waste water.
• Maps of flood risks in arid regions as a decision support tool.