Flood forecast for No.2 flood of Changjiang River in 2024 and regulation benefits of Three Gorges Reservoir
Since July 2024,the No.1 and No.2 floods occurred successively in upper and lower reaches of Changjiang River.Reasonable water condition forecasting and reservoir scheduling are key to coordinating the flood control needs of the upper and lower reaches of the Changjiang River,as well as controlling the risk of submergence at the tail of the Three Gorges Reservoir.The development stages of the rain and water conditions during the No.2 flood are outlined.The characteristics of rainstorm floods are summarized,the composition features of floods are analysed,and the accuracy of water condition forecasts at major sites along the Changjiang River is evaluated.By analysing the joint scheduling of group reservoirs,with the Three Gorges as the core,in the up-per reaches of the Changjiang River,the benefits of reservoir scheduling during No.2 flood is quantified.The analysis results indi-cate that:during the No.2 flood period,the rainfall area experienced high overlap and strong local extremes.The Minjiang and Jialing Rivers in the upper reaches of the Changjiang River encountered floods,and the floods in the Three Gorges area were par-ticularly prominent.Eight days in advance,we forecasted that there would be a significant rise in water levels at the end of the first ten days of July,providing ample time to lower the water level of the Three Gorges Reservoir in advance.From July 5th to 9th,the Three Gorges Reservoir impounded a flood volume of about 550 million cubic meters,which reduced the water level at Qilishan Station of Dongting Lake by 0.30 m and enabled the water level at Qilishan Station to recede from the warning level one day earli-er,thus supporting the emergency handling of the flood situation in Tuanzhou Dyke,Huarong County,Hunan Province,by reducing the pressure of flood defense and the difficulty of closing the broken dykes.Through the joint dispatch of the upper Changjiang River reservoirs,the water level at Cuntan Station at Chongqing City was lowered by 1.36 m,avoiding the its water level from ex-ceeding the warning level.The No.2 flood was effectively staggered with the No.1 flood during its progression to the middle and lower reaches,reducing the water level of the main stream in the middle and lower reaches by 0.70 to 3.10 m,greatly easing the flood defense pressure in the middle and lower reaches of the Changjiang River.The research results can provide reference for flood control and disaster reduction in the Changjiang River Basin.
No.2 flood of Changjiang River in 2024reservoir schedulingflood forecastTuanzhou DykeThree Gorges Reservoir
万方数据
维普
