Physico-chemical and Biological Evaluation of the Quality of Surface Water in the Wadi El-Melha Watershed (North-East Algeria)

This environmental study targeted the ecological assessment and classification of the waters' state of health at the level of the Wadi El-Melha watershed flowing from Lake Mellah (northeast of Algeria) through Physico-chemical parameters measured in situ and measured in the laboratory, and the biological quality achieved through Odonates as bio indicators of ecological potential in watercourses. The aim is to conserve the potential of the ecosystem (biotope, habitat and reproduction of species, flow of water, rambling of the bed). The waters' quality of the Wadi El-Melha watershed seems to be generally good at the end of this study despite some recognized disturbances in some sections, which are essentially linked to alterations by, nitrites nitrates and phosphates which in places influence the quality of the surveyed river. In terms of biological quality which was assessed using ecological indices, the results revealed a stability of the stand during the study period. The odonatological procession is diverse (Shannon index H'= 2.26), and it is in equilibrium (equitability index E = 0.90). Based on the classification proposed by [1], Wadi El-Melha is among the "middle" rivers, meaning a "moderately polluted" classification.