Surface water Quality modeling using SWAT for ARDAk Basin of Mashhad

During last decades, despite developing various reports and techniques, due to over expansion of water pollution, hydrological models have become sophisticated tools for water resources management and planning because of their remarkable ability to analyze information and economic savings resulting from their application. In this study, using the SWAT semi-distributed model, which operates on the basis of physical and non-physical processes governing the water environment, quantitative and qualitative modeling was developed for Ardak River which supplies a significant part of water demand in drinking and agricultural sectors of Mashhad mega city. So, this research is going to provide a right tool for future planning and design making.

After entering the information and constructing the model in Swat, for calibration and verification of stream flow, NO3, MINP, TSS, DO and CBOD in SWAT-CUP model, sampling and testing of different water quality parameters were performed in 12 monthly periods from march 2019 to February 2020.

The results showed that except for nitrate, the amount of other water quality parameters such as phosphorus, sediment and carbonaceous organic matter is higher in wet seasons.

The developed model has a considerable ability to simulate the actual condition of the river and it can be applied to define and implement a variety of scenarios affecting water quality for identifying the best practices by testing different options.