Application of Water Quality Index for Surface Water Quality Assessment Boukourdane Dam, Algeria

Abstract

Boukourdane dam in Northern Algeria plays a fundamental role in the local society as a source of irrigation and drinking water. In order to characterize the temporal variability of water quality in the dam lake, monthly monitoring was conducted for a period of 2 years (January 2013–January 2015) at four sites. The water in the dam tended to be alkaline, with the highest pH = 9.95 recorded in the spring of 2013. The highest value of temperature was recorded in summer (37.6 °C). The dissolved oxygen levels varied between 2.58 and 11.61 mg L−1. Nitrates were low and the fecal coliform ranged between 85.60 and 1099.67 UFC mL−1. The overall water quality in the Boukourdane dam is medium to good according to SEQ-EAU (Normes de qualité des eaux des masses d’eau naturelles [4]). To confirm these results, we calculated the water quality index (WQI); during the study period, the WQI varied between 60 and 72. The water quality is frequently impaired; conditions often depart from desirable levels which classified the water quality as medium. There was a general trend of decrease in the summer and autumn of 2014 and this is the result of natural processes (degradation of organic matter as well as the concentration of nutrients in those seasons).