EVALUATION OF THE WATER QUALITY OF ALGERIEN DAMS

This study aims to give an overview of the water quality of forty dams located in the west and eastof Algeria. It included a Physico-chemical characterization to highlight many factors that play arole in determining the quality of these waters such as: pH, Dissolved oxygen (O2), Nitrate (NO3),Nitrite (NO2), Phosphates (PO4), Organic matter (OM), Dry residue (DR), Biochemical OxygenDemand (BOD5) and Chemical Oxygen Demand (COD). The waters of the western dams have veryhigh dry residues, which could be linked to the terrain crossed and the high erodibility of the soilsin these regions. The highest level of nitrate (10 mg/l) was recorded in the BaniBahdel dam in thewest and similarly high values of BOD5 and COD, which show another indicator of water qualitydeterioration water at the dams in the western region. The application of statistical methods,Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA) made it possibleto give a classification to these dams according to the degree of water contamination. The resultsplaced the western dams in the medium to very high pollution category. The eastern dams seemless affected by pollution.