Evaluating linked treatment-reservoir operation system to mitigate nitrate concentration of agricultural runoff

The present study proposes a framework to evaluate utilizing a combined system including water treatment system and reservoir operation optimization to control water quality impact of agricultural runoff on the aquatic habitats. Soil and water assessment tool was applied in the river basin scale to simulate outflow and nitrate concentration in the target sub-basin. Furthermore, an operation optimization model of the reservoir was utilized to analyze different scenarios of using water treatment system and reservoir operation to mitigate nitrate concentration impacts. Results indicated that the reservoir should be considered as a tool for controlling water quality in combination with the water treatment system for the cases in which a constructed dam is available at upstream. According to the results in the case study, storage loss is the same in all of the scenarios. Moreover, reservoir is able to compensate reduction of the treatment system area for mitigating water quality impacts. The reliability of water supply is considerably changed in different scenarios. Analysis corroborated that using the optimal reservoir operation is the best scenario in the case study. However, it might be different in other case studies. The most important advantage of the proposed method is to provide an integrated framework to analyze combined scenarios to mitigate nitrate impact in the river basin scale. It is recommendable to utilize the proposed framework in the decision-making system to construct water treatment systems. In fact, it might reduce costs drastically