Optimization of water quantity and quality in Mahabad River by SWAT model

Water quantity and quality joint operation is a new method in the present dams’ operation research. This paper coupled a water quantity and quality joint operation model (WEAP) and a genetic algorithm, with the Soil and Water Assessment Tool model. Together, these tools are used to explore a reasonable operation of dams and floodgates in a basin scale. Mahabad River Catchment in the Urmia Lake basin was selected as a case study that caused a 33% increase agricultural efficiency, and enhanced by 51% in terms of biological reservoir water quality. The results showed that the coupled model of Mahabad River Catchment more realistically simulates the process of water quantity and quality control by dams and floodgates. This integrated model provided the foundation for the research of water quantity and quality optimization on dam operation. The results also suggested that current water quality of Mahabad River can improve following the implementation of the optimized operation of the main dams and floodgates. By pollution control and water quantity and quality joint operation of dams and floodgates, water quality of Mahabad river changed significantly, and the available water resources increased by 14.2%, and 10% at the downstream sites of Mahabad River Reservoir, and Yusefkand floodgate, respectively. The method played an active role in improving water quality and water use efficiency in Mahabad river basin. The research can provide the technical support for water pollution control and ecological restoration in Mahabad River Catchments.