Physical and Chemical Characterization of the Surface Waters of Djemaa Wadi (Blida, Algeria)
Oued Djemaa is the largest tributary that feeds El Harrach wadi. It comes from Atlas Blidéen (the Tablat Mountains); its catchment area covers an area of 225 km2. The waters of this wadi show a strong alkalinity and a strong mineralization. The upstream waters are well oxygenated compared to the downstream waters. High values of nutrient salts were observed mainly at stations located near agricultural lands. Chlorides exceed 600 mg/l at downstream. The water situation of Wadi Djemaa is poor in the downstream part, the biological oxygen demand (BOD5) reaches a maximum of 255 mg/l and the chemical oxygen demand (COD) exceeds 350 mg/l level of the S4 (Larbaâ city).