Evaluation of Self-Purification Potency and the Role of Dissolved Oxygen in the Kor River Water Quality (Case study: Downstream of Doroodzan Dam to Tashk-Bakhtegan Lake)

Kor River is one of the most valuable water sources in the Fars province, which has special economical and ecological values and conditions. In the current research, QUAL2K software was used to identify and understand changes and to predict water quality of Kor River for its future urban, agricultural, and industrial plans. Then by field studies, 7 appropriate points between downstream of Doroodzan dam to Tashk-Bakhtegan lake were determined for sampling and dissolved oxygen was measured by collecting and analyzing samples, in September and March which have the lowest and the highest water amounts in the year. The minimum and the maximum DO simulated by the model in September and March were 5.59 in Khan Bridge and 8.25 mg/l in Shahid Ghanizadeh Bridge, and 5.71 in Khan Bridge and 7.91 mg/l in Shahid Ghanizadeh Bridge, respectively. Reason of the decrease of Dissolved oxygen in Khan Bridge Station is discharge wastewater of Shiraz Petrochemical Complex and Marvdasht’s wastewater to it. After this, because of decrease of wastewater’s effect and existence bridges and dikes like Bande Amir, Rahmat Abad Bridge and Hasan Abad Brige, they can increase turbulence, aeration and self-purification of Kor River and as a result increase of dissolved oxygen in it.