2024年长江暴雨洪水特点与启示

Characteristics and enlightenment of rainstorms and floods during flood season of Changjiang River in 2024

2024年主汛期,长江干流接连发生3次编号洪水,部分支流发生特大洪水,中下游干流城陵矶以下河段及两湖湖区全线超警,主要控制站洪峰水位居有实测记录以来第7~9位,其中汉口站最高水位为21世纪以来第3位(仅次于2020年和2016年)。2024年长江暴雨洪水受梅雨、台风等影响成因复杂,为深入分析洪水特点,系统梳理了暴雨洪水发展过程,详细分析了洪水特点与成因,并以长江流域水模拟体系为基础对洪水进行了还原和定性分析。结果表明:2024年长江暴雨洪水具有降雨总量大、强度大、洪水编号早、超警河流多、洪水涨势猛等特点。从成因上看,主要是暴雨叠加效应突出、极端性强,台风影响恶劣,同时两湖洪水严重遭遇,洪水顶托宣泄不畅,沿江排涝影响突出。通过还原分析表明,2024年长江洪水定性为中下游型区域性大洪水。通过总结此次洪水特点,初步探讨了当前极端天气事件多发、散发、重发的背景下,长江流域防洪面临的新情况与新问题,以期为未来一段时间长江流域洪水防御工作提供参考。

In the main flood season of 2024,the main stream of the Changjiang River experienced three consecutive numbered floods,and some tributaries suffered severe flooding.The sections below Chenglingji in the middle and lower reaches of the main stream,as well as the entire Two Lakes region(Dongting Lake and Poyang Lake),exceeded the warning water levels.The peak water levels at the main control stations ranked 7th to 9th among those since recorded measurements,and the highest water level at the Hankou Station hit the third highest in 21st century(second only to those in 2020 and 2016).In 2024,the causes of the rainstorm and flood of the Changjiang River were complex due to the influence of plum rain and typhoon.In this paper,we systematically reviewed the development process of the rainstorm and flood,carried out a detailed analysis on the characteristics and causes of the floods,and qualitatively and quantitatively analyzed the flood based on the water simulation system of the Changjiang River Basin.The results indicate that the 2024 Changjiang River rainstorm and flood is characterized by a large total rainfall,high intensity,early flood numbering,numerous rivers exceeding warning levels,and rapid flood surges.From a causative perspective,the prominent factors include the superimposed effect of rainstorms,extreme conditions,adverse typhoon impacts,and severe encounters of floods in the two lakes.These factors led to obstructed flood discharge along the Changjiang River due to backwater effects,significantly affecting drainage.Restoration analysis indicates that the 2024 Changjiang River flood is classified as a regional major flood in the middle and lower reaches.By summarizing the characteristics of this flood,we preliminarily discussed the new situations and challenges of flood control in the Changjiang River Basin under the current context of frequent,sporadic,and recurring extreme weather events.The research aims to provide reference and guidance for flood control efforts in the Changjiang River in the coming period.