Optimal Rule Curves for Operation the Euphrates River Concerning Tharthar Reservoir as a Case Study

Abstract

In this study, the Discrete Differential Dynamic Programming (DDDP) method is utilized to identify the optimum rule curves and policies for the Tharthar Reservoir by adopting an objective function to reduce the release and storage losses. The input data for the optimization model represents the historical data for the Tharthar Reservoir within the Euphrates River Basin from October 2000 to September 2021. The years within this period will be categorized as two sequential wet and dry years for the reservoir operation through the development period of October 2022 to September 2059. In the first scenario, TH1, the plan is unsafe during the planning period of the operation because there is a high deficit in storage and outflow. The summation of the deficit in storage and outflow after applying the TH1 scenario is equal to 52671 million cubic meters (MCM). The second scenario, TH2, is an alternative scenario for operating the Tharthar Reservoir. The summation deficits from using TH2 are equal to 13071 MCM for storage and outflow. The results simulated for the monthly storage were compared with the measured data for a reliability test. Also, the projected water supply calculated by the optimization model by DDDP was compared with the WEAP model. From this comparison, the three statistical parameters, R 2 , NSE, and RSR, were evaluated as an acceptable level and a good agreement of the DDDP and WEAP model performance.