极端气象水文条件下长沙城区内涝成因及防治对策

Causes and Countermeasures of Water-logging in Changsha Urban Area under Extreme Meteorological and Hydrological Conditions

采用极端降雨阈值法,分析了近年来长沙市城区极端降水频次呈增大趋势。基于“2017·7·2”长沙极端暴雨内涝事件统计结果,分析内涝的主要区域及成因。结果显示城区内涝的主要区域是地势低洼的道路和居民小区,且排水设施设计标准偏低、管理问题及外河排水条件影响是内涝的主要成因。通过典型区域剖析了内涝应对措施及在2020年极端暴雨中的应用效果,发现排水设施建设标准提高不是内涝管理的唯一出路。从保持城市弹性角度,提出新型城镇化建设背景下内涝防治的4大主要对策,为城市内涝防治措施建设与管理提供参考。

Using the threshold method of extreme rainfall, the increasing trend of extreme rainfall frequency in Changsha urban area in recent years is analyzed. Based on field survey on the catastrophic rainstorm event on July 2,2017, the main areas and causes of water-logging are statistically analyzed. The results show that the main areas of urban waterlogging are low-lying roads and residential areas, and the low design standards of drainage facilities, management problems. The influence of drainage conditions of outer rivers are the main causes of waterlogging. Based on the analysis of waterlogging countermeasures in typical areas and their application effects in the extreme rainstorm in 2020, it is found that the improvement of drainage facility construction standards is not the only way out for waterlogging management. From the perspective of maintaining urban elasticity, four major countermeasures for waterlogging prevention and control under the background of new urbanization construction are proposed, providing reference for the construction and management of urban waterlogging prevention and control measures.