从2020年长江上游洪水看流域防洪对策

Flood Control Strategies for the River Basin Enlightened by the 2020 Upper Yangtze River Floods

2020年长江上游和中下游先后发生特大洪水,其中干流编号洪水全部发生在上游,构成了长江流域洪水的主要部分。首先回顾2020年洪水及洪灾情况,然后根据历史上几次特大洪水过程和历年实测资料,分析长江上游洪水特征、洪灾类型及特点,最后提出新时代长江流域洪水整体防御战略及山洪灾害防治战术。研究表明:金沙江洪水是长江上游洪水基础部分,岷江、嘉陵江和干流区间是洪峰的主要来源,三者洪水遭遇是产生上游特大洪水的主因,上游洪水又是全流域特大洪水的基础和重要组成部分。目前造成洪灾死亡人数最多的是山洪以及山洪引起的地质灾害,财产损失最大的是中下游及湖泊地区。未来堤防仍然是防洪的基础,提高沿江城市防洪标准主要手段是控制性水库的联合优化调度,而减少洪涝灾害损失最有效的途径是给洪水以空间的自然解决方案等非工程措施。

In 2020,the upstream and mid-downstream of the Yangtze River experienced massive floods,with the major mainstream floods occurring in the upper Yangtze River.In this study,we first reviewed the floods and their related losses,and then analyzed the characteristics of flooding disasters in the upper Yangtze River based on several catastrophic floods in history.Finally,we proposed the integrated strategies for flood defense and the control tactics for flash floods in the Yangtze River Basin in the new era.Our results show that the floods in the Jinsha River underlay the floods in the upper Yangtze River,whereas the flood peaks were primarily attributed to the inflow from the Minjiang River,the Jialing River and the mainstream interval.The cooccurrence of floods in the aforementioned three tributaries led to the mega-floods in the upper Yangtze River,which formed the foundation and an important component of the basin-wide floods.At present,flash floods and accompanied geological disasters caused the largest number of deaths,and the biggest property losses occurred in the middle-lower reaches and the lake areas.In the future,the embankments will remain the basis of flood control.The main means to improve flood control standards of urbans long the river will rely on the joint optimal operation of reservoirs.In addition,the most effective way to reduce flood losses will be non-engineering measures such as natural solutions that give space to floods.