1Faculty of Water Science and Engineering, Shahid Chamran University, Ahvaz, Iran
2Faculty of Physical Geography and Quaternary Geology, Stockholm University, Stockholm, Sweden
3Faculty of Environmental Health, Ahvaz Jondishapour University of Medical Science, Ahvaz, Iran
4School of Civil Engineering, College of Engineering, University of Tehran, Tehran, Iran
Human activities in the recent years have considerably increased the rate of water pollution in many regions of the world. In this case study, the main sources of wastewater discharging into the Gargar River were identified. Using river and point source flow rates and water quality parameters measured along the river, the river water quality was simulated using a commonly used, one-dimensional water quality model, the QUAL2K model. Simulated values of DO, CBOD, NH4-N and NO3-N demonstrated the accuracy of the model and despite a significant data shortage in the study area, QUAL2K model was found to be an acceptable tool for the assessment of water quality. Still, for this case study, it was found that the model was most sensitive to river and point source flows and moderate to fast CBOD oxidation, and nitrification rates.