Impact de l'Agriculture et des Formations Salifères sur la Qualité des Eaux Souterraines : Cas de l'Aquifère Superficiel de Ain Djacer (Est Algérien). Impact of the Agriculture and the Saliferous Formations on the Quality of Under groundwater: Case of the Superficial Aquifer of Ain Djacer (East Algeria)

The superficial aquifer of Ain Djacer, located in the West of Batna in the East of Algeria, is strongly requested by pumping. The use of its water resource for the irrigation of cereals and the market gardening and the intensive use of the nitrate fertilizers contributed to the deterioration of the quality of water through the rise in the content of nitrates. Thus, we noticed between the period of low waters 2003 and high waters 2004, an increase in the nitrate concentrations of almost 20 % of the sampled water points. These contents vary between 3 and 125 mg/l but in general they remain relatively stable in spite of these flows entering the irrigated perimeters. This stability can be explained only by the existence of a natural denitrification, in the groundwater or the unsaturated zone. Adding to this nitrogen phenomenon, water of the area is largely influenced by the salted formations of the Trias where the chlorinated sodic and sulphated calcic facies represent nearly 90 %. These saliferous and nitrogenized tendencies were highlighted in a clear way by the analysis in principal components where we can observe at the same time an opposition between the saliferous formations and the carbonated formations on the one hand and nitrogen and the rest of the elements on the other hand.