A Study on Optimal Operation of Gate-Controlled Reservoir System for Flood Control based on PSO Algorithm combined with Rearrangement Method of Partial Solution Groups

Abstract The discharge flow process for flood control of a gate-controlled reservoir is performed by opening and closing the reservoir floodgates. Determining the optimal operation rules of the reservoir system consisting of fully opened floodgates according to time, taking into account the discharge characteristics of the gate-controlled reservoirs during the flood period, was an important demand raised by many reservoir managers. This paper introduces a novel optimization method based on the PSO algorithm combined with the rearrangement method of the particle solution groups to directly determine the optimal operation rules of the reservoir system which consists of the number of fully opened floodgates according to time. When applying the PSO algorithm, unlike previous research that uses the discharge flow process as decision variables, in this paper, the PSO-algorithm which uses the operating plan of floodgates as the decision variables is employed to determine the initial solution for the minimal flood peak discharge in the downstream. This initial solution is modified as a more reliable and realistic optimal operation rule of the reservoir that simultaneously satisfies the maximum flood peak elimination condition and the minimum operation of reservoir floodgates by the newly developed rearrangement method of partial solution groups. To validate the proposed method in this paper, two reservoirs placed in the upstream of Chongchen River and its tributary in the DPR of Korea are selected as a case study. In addition, the PSO algorithm and progressive optimality algorithm (POA) which use the discharge flow process as the decision variables were conducted to compare the performance with the newly proposed method. The validation results show that the method proposed in the paper is superior to the two methods and sufficiently reflects the demand of reservoir managers, which can be effectively applied to the determination of the optimal operating rule of the gate-controlled reservoirs during the flooding period.