Ce travail a été réalisé en zone aride et concerne la salinité des eaux de la nappe du MioPlio- Quaternaire de la plaine d’El-Outaya (région de Biskra au sud algérien). Cette plaine est le résultat d un remplissage néogène qui repose en discordance sur tous les terrains antérieurs mésozoïques et paléogènes. Le Trias avec son diapir de sel reste un élément très important dans cette plaine par sa composition lithologique et ses contacts anormaux avec les autres formations. Le contact de l aquifère étudié avec le substratum se fait soit par des conglomérats, soit par des argiles. L’hétérogénéité de la nappe du Mio-Pliocène se caractérise par la présence d argile dans des proportions variables. L’évaporation dans la région est très intense et consomme la majorité des précipitations. La combinaison entre les outils, géologique, géophysique, statistique et chimique dans l’étude du problème de la salinité permet de déterminer l’origine et l évolution dans l’espace de cette dernière. Les analyses effectuées indiquent la présence en fortes concentrations des éléments CT, S042\ Na + et Mg+. Dans la partie nord et ouest, les eaux sont caractérisées par un faciès chloruré sodique (influence de la halite), à Test, le faciès sulfaté magnésien domine (influence du gypse). Entre ces deux faciès, on note une zone où les eaux sont mixtes, caractérisées par un faciès sulfaté sodique (échange de base). L’interprétation thermodynamique a permis la détermination de l’influence des minéraux évaporitiques à des degrés variables dans la composition chimique des eaux. Ces minéraux sont à l’origine de la salinité des eaux de la région. Les minéraux carbonatés se trouvent sursaturés dans l’eau.
The world-wide crisis of water will make that the transboundary water resources will be the object of tensions and litigations increasingly marked. Also, the transboundary conflicts on fresh water intended to the categories of traditional uses are subjected to a growing attention on behalf of national and international organizations. Each case of conflict, related as well to surface water as groundwater, has its accurate characteristics and to appreciate its relative importance, it is necessary to consult a broad documentation based on reports of commissions, organizations or groups of research. According to criteria and data taken into account, the situation is some times appreciated differently.
Reduction of water resources has led water managers to search for adequate solutions to respond to increasing demand. Artificial recharge of aquifers by resources drawn from far away is a mobilisation mode adopted especially in arid areas. The cost of this operation is often very high but counterbalanced by the advantages provided by this mean: • mobilisation of this resource in zones were it's very available; • injection by different means in aquifer zones whose characteristics are known; • a storage mode which allows to conserve resources from evaporation, as opposed to storage in dams that are also confronted to deposits that reduces considerably their capacity; • Artificial recharge can also benefit from natural mean of transport when it takes into account the groundwater hydraulic gradient at a time of choosing injection zones. Artificial recharge by direct recharge on permeable zones constitutes the most used mean but such zones are the most vulnerable to pollution. The cartography of the groundwater pollution potential of a given area, combined to repartition of favourable zones to artificial recharge, constitute a tool to decision making concerning the choice of recharge zones that takes into account environmental aspects. This approach is applied to the El Madher plain which is located just at the North of Batna city (North-East of Algeria).
The predetermination of the runoff in the non gauged basins constitutes the objective of numerous researches because of a lack of data covering them. Thus, the use of mathematical models became the suitable approach. Runoffs at the exit of basins, in addition to being influenced logically by rainfalls and their intensities, they are under the influence of other factors which condition the surface discharge such as the physiographical parameters of the basins, lithology, vegetation cover and evaporation. The aim of this work is to seek statistical relations which bind runoff observed at the exit of basins to rainfalls and some physiographical factors for basins of Algeria between September 1985 and September 1993. The simple and multiple correlations carried out on 23 basins made it possible to emphasize that some physiographicalcharacteristics are explanatory of the variance of the runoff to significant thresholds.
