Reducing impacts of rice fields nitrate contamination on the river ecosystem by a coupled SWAT reservoir operation optimization model

Abstract The present study proposes a multipurpose reservoir operation optimization for mitigating impact of rice fields’ contamination on the downstream river ecosystem. developed model was applied in Tajan River basin Mazandaran Province, Iran, which is main crop. We used soil and water assessment tool (SWAT) to simulate inflow nitrate load at reach. Nash–Sutcliffe efficiency coefficient measure robustness SWAT. NSE indicated that SWAT acceptable fields. results structure three metaheuristic algorithms including differential evolution algorithm, particle swarm biogeography-based algorithm were utilized process. Reliability index, mean absolute error failure index algorithms. Fuzzy Technique Order Preference by Similarity Ideal Solution select best algorithm. Based results, method optimize case study. reliability supply are 0.6 5 million cubic meters, respectively. Furthermore, 0.027. Hence, it could be concluded proposed system reliable robust mitigate losses simultaneously. However, its performance not perfect minimizing all simulated months.