Study On Water Supply Regulation Of Reservoir Group In The Middle And Upper Reaches Of The Yangtze River

In order to adapt to the new normal of economic development and create a new situation of the overall rise of the central region of the Yangtze River,China has vigorously promoted the implementation of the strategy of "development of the Yangtze River Economic Belt".With the rapid development of river basin urbanization and industrialization,the water demand for industry,agriculture and life in the middle and lower reaches of the Yangtze River is increasing.However,due to the uneven inflow of runoff in the middle and upper reaches of the Yangtze River,the inflow in non flood season does not meet the demand for water supply.The Yangtze River basin reservoir group is the largest giant reservoir group in the world,with large storage capacity,which provides the possibility to carry out the joint operation of the reservoir group to solve the downstream water supply demand.Based on this,this paper takes 7tributary basins and 29 reservoirs in the middle and upper reaches of the Yangtze River as the research object,and carries out the research on the joint water supply operation facing the water supply demand of five provinces and one city in the lower reaches.The main contents are as follows:Firstly,The runoff characteristics and the contradiction between supply and demand in the middle and upper reaches of the Yangtze River Basin were analyzed.According to the historical runoff data from 1956 to 2012,the inflow of 29 reservoirs under five typical annual conditions is determined as the input of the medium and longterm operation model of cascade reservoir groups.Then,Mann Kendall trend test method is used to analyze the variation trend of the inflow.The results show that the inflow of Jinsha River,the main stream of the upper reaches of the Yangtze River and Dadu River Basin is on the rise,and the inflow of Yalong River,Minjiang River The runoff from Jialing River,Wujiang River and the middle reaches of the Yangtze River is decreasing.Secondly,The multi-objective optimal operation model of cascade reservoirs in the middle and upper reaches of the Yangtze River is established.According to the water supply demand of five provinces and one city in the lower reaches of the river,a mathematical model is established,which takes the minimum water shortage of the Three Gorges section in the water supply process,the maximum total power generation of cascade hydropower stations in the basin and the maximum total water storage at the end of the operation period of the reservoir group in the basin as the optimization goal.The model is solved by NSGA-Ⅱ algorithm and Pareto optimization.The above model is used to calculate the overall optimal operation of the river basin and the individual optimal operation of the river basin for the cascade reservoirs in the middle and upper reaches of the Yangtze River.The results show that the overall optimal operation of the river basin has a greater advantage in power generation compared with the individual optimal operation of the river basin.The inflow,as the main factor affecting the operation results of the river basin,determines the water supply,power generation and water storage status of the river basin.Thirdly,At the same time,the compensation water supply strategy of Cascade Reservoirs Considering the uncertainty of runoff is studied.According to the results of the overall optimal operation and the individual optimal operation of the river basin in different typical situations,the river basin that is most affected by the compensated water supply is selected as the typical river basin,and its elastic operation space analysis is carried out,and the compensation operation strategy of the cascade reservoirs in the middle and upper reaches of the Yangtze River is proposed.Considering the uncertainty of runoff,the compensation operation of cascade reservoirs in the middle and upper reaches of the Yangtze River under three typical scenarios is studied,and the compensation water supply operation strategy is formulated.