Quality of water and their ability to irrigate the area of El-Ghrous in the wilaya of Biskra (Algeria)..

The region of El-Ghrous, has known an important agricultural rise which required the extensive use of inputs,where the risk to cause pollution of ground water in the region (Mio-Pliocene and Lower Eocene).These two layers are collected from boreholes of which there are 40 holes at the lower of the Eocene and 13 atthe Mio-Pliocene.Chemical analysis conducted in the laboratory of CRSTRA ( November 2010), showed that the waterwas particularly rich in SO42-, Ca2 +, Na+, K+, Mg2+ and HCO3-. In detail, we note that the sulfates are highconcentrations reaching values ranging from 1.43 g.l-1 to 3.14 g.l-1 in the water of theMio-Pliocene and 0.16 g.l-1 to 2.24 g.l-1 in the water from the lower Eocene, which gives the water acalcium sulfate facies sometimes to sodium sulfate. The measured conductivity is still high for the waters of theMio-Pliocene with 5.62 mS/cm; however we notice relatively drop for the waters of the lower Eocene(2.55mS/cm).These concentrations determined, led to the calculation of the SAR. The latter combined with theconductivity to determine the suitability of ground water for irrigation.