Research on joint flood control operation rule of parallel reservoir group based on aggregation–decomposition method

Abstract

With the continuous construction of reservoir group systems and the improvement in flood control objectives in China, a demand has arisen for joint flood control operations of reservoir groups in river basins. However, the existing conventional flood control operation rule (CFCOR) of most reservoirs are based generally on a simple discriminant and there is a lack of coordination among the reservoir group. Further, owing to a shortage of high-precision, long-term forecasting schemes and forecasting professionals for reservoirs in small and medium river basins, it is difficult to obtain acceptable results when applying the forecasting-operation mode. Therefore, an optimal joint flood control operation rule (OJFCOR) of parallel reservoir groups is proposed in this study based on the Aggregation–Decomposition method (AGDP). This proposed rule comprises the aggregated reservoir flood control operation chart and the decomposition strategy named occupied flood regulation storage capacity ratio method (OFRSCR). We applied the simulation-optimisation method (SLOS) nested annealing accuracy penalty function method-adaptive multi-variant particle swarm optimisation (AAPF-AMPSO) to optimise OJFCOR, with the objective function being the maximum average peak-cutting rate of the flood control section. A case study was conducted with a parallel reservoir group located in the upper reaches of the Lijiang River basin (URLRB). Our results showed that, compared with the widely used inflow ratio method (IR), the performance of OFRSCR was a more suitable decomposition strategy and superior in maintaining the synchronisation of the parallel reservoir group. Further, OJFCOR showed a satisfactory peak-cutting effect on floods with different rainstorm centres and flood magnitudes, with the average flood peak-cutting rate of 37.68%, which is superior to those of CFCOR (25.26%) and DP (32.69%), but inferior to that of POA-DPSA (45.23%). Besides strong peak-cutting ability and strong adaptability, OJFCOR also has advantages of smooth outflow process and being convenient for professional operators. Generally, the OJFCOR proposed in this research was found reasonable and effective, and it was shown suitable for practical real-time flood control operations and reducing the effects of flood disasters.