Evaluation of BOD and DO for Diyala River by Using Stream Water Quality Model

Abstract

This paper was studied the biochemical parameter (BOD5) and (DO) for Diyala River (Iraq) which regard significant tributary for the Tigris River. Water samples have been collected from Diyala River along different points between Baquba to Al-Zafarania and were analyzed for various water quality parameters during low flow season (November). The study involves application of stream water quality model QUAL2K model to simulate and predict the dissolved oxygen (DO) and biochemical oxygen demand (BOD5) profiles for Diyala River in a stretch of 251 kilometer. Model output showed that DO in the entire river was within limit of not less than 4 mg/L. For Carbonaceous Biochemical Oxygen Demand CBOD, the entire river may be divided into three main reaches; first one is extended from Kalar City (0 km) to Jalawla (46 km) and have CBOD concentration of 2 mg/L , the second reach has CBOD range (2-4) mg/L in which begins from Sadiyah city and extend to near Buhriz city city(168km), the third reach extends from Khan Bani Saad city to Al-Zafaraniah (251km) in the south east of Baghdad city confluence point with Tigris River which has CBOD concentrations of more than 5mg/L.