Study On Optimal Operation Of Reservoir Group Flood Control In Liuxihe River Basin

The frequent flood and waterlogging disasters in the Liuxihe River basin have seriously hindered the development of the society.It is of great practical significance to study the joint optimal operation of major reservoirs in Liuxihe River basin for improving the flood control capability of large and medium reservoirs and reducing the flood disaster of Liuxihe River.The main research contents and conclusions are as follows:(1)Based on the method of integrated unit line and the method of reasoning formula,the design flood of Jiuwantan Reservoir with frequency of P=1%,P=2%,P=5%is calculated in this paper,the calculation of typical design flood hydrograph in time-varying environment is studied.(2)The optimal operation model for flood control of Reservoir Group is established,the mathematical model with peak clipping criterion maximization as the objective function is established,and the improved successive approximation dynamic programming algorithm(DPSA)is proposed,the optimal operation of flood control for reservoir group is studied.(3)Based on the improved successive approximation dynamic programming algorithm,the optimal flood control operation model of four reservoirs is numerically calculated,and the optimal operation of typical design flood under different frequencies is studied.The results show that:(1)Under the condition of once-in-50-years flood,the peak reduction rates of four reservoirs are increased by 12.62%,8.79%,31.09%and6.38%respectively;After the optimal dispatching of the outlet section of the basin,the discharge decreased by 612m~3/s.(2)After comparing the optimal dispatching of the model by using the conventional dispatching algorithm and the improved successive approximation dynamic programming algorithm,it was found that,in the case of once-in-100-years flood,the Liuxihe Dam discharge decreased from 1262.14m~3/s to1153.63m~3/s,and the peak cutting rate increased from 69.78%to 72.37%,up by 2.59%The maximum discharge of Huanglongdai Reservoir decreased from 554.57m~3/s to444.56m~3/s,the peak-clipping rate increased from 63.93%to 71.08%,7.15%,and the maximum discharge of Jiuwantan Reservoir decreased from 165.56m~3/s to 97.74m~3/s,the peak-cutting rate increased from 43.94%to 66.90%,and the maximum discharge of Helong Reservoir decreased from 229.25m~3/s to 202.84m~3/s,and the peak-cutting rate increased from 59.13%to 63.84%,and increased by 4.71%The maximum discharge at the outlet section of the basin decreased from 2346m~3/s to 1912m~3/s.