汉江这轮大洪水，缘何“悄无声息”？

Core Viewpoint - The recent floods in the Han River, despite being significant in terms of rainfall and frequency, have been effectively managed through advanced technology and coordinated water resource management, preventing any overflow in the lower reaches of the river [1][2][3]. Group 1: Flood Events and Management - The Han River experienced five numbered floods since September, with a cumulative rainfall of 518 millimeters in the upper reaches, approximately double the average for previous years [2]. - The floods are described as the "most concentrated autumn floods" since records began, yet the lower reaches of the Han River did not exceed warning levels, and daily life remained unaffected [2][3]. - The effective management of these floods was attributed to the coordinated operation of upstream reservoirs, particularly the Danjiangkou Reservoir, which played a crucial role in flood control [2][3]. Group 2: Technological Advancements - The implementation of the "Digital Twin Danjiangkou Project" and the trial operation of rainfall radar have significantly improved the accuracy of rainfall forecasts, aiding in precise flood management [2]. - The use of shared meteorological data has enhanced the ability to predict short-term rainfall events, supporting refined flood control measures [2]. Group 3: Resource Management - The flood management strategy also focused on resource utilization, with a total of 11.7 billion cubic meters of floodwater being retained in the upstream reservoirs, including 8.5 billion cubic meters in the Danjiangkou Reservoir [3]. - This approach not only addressed immediate flood risks but also ensured sufficient water supply for the South-to-North Water Diversion Project in the upcoming year [3].