浙江省剡溪小流域“2023.7.22”短历时暴雨山洪致灾成因分析  

Analysis of the causes of"2023.7.22"short-duration flash flood in Shanxi River Watershed,Zhejiang Province

作　　者：王淑英 孙英军 王雨歌 WANG Shuying;SUN Yingjun;WANG Yuge(Hydrological Management Center of Zhejiang Province,Hangzhou 310009;State Key Laboratory of Hydraulics and Mountain River Engineering,Sichuan University,Chengdu 610065)

机构地区：[1]浙江省水文管理中心,杭州310009 [2]四川大学山区河流保护与治理全国重点实验室,成都610065

出　　处：《中国防汛抗旱》2024年第5期32-37,共6页China Flood & Drought Management

基　　金：浙江水利重大科技项目(RA2406);浙江水科技重点项目(RB2425);国家自然科学基金重点项目(52239006)。

摘　　要：2023年7月22日,浙江杭州富阳区遭遇短历时强降雨,诱发山洪灾害,造成剡溪小流域人员伤亡及财产损失。为全面了解此次暴雨山洪过程,揭示受灾区山洪致灾机制,基于实地调查资料,从降雨特征、山洪过程及人类活动3方面分析山洪致灾特征。结果表明,短时强降雨是该区域山洪致灾的主要成因,站点最大1 h雨量100.5 mm,最大3 h雨量150.0 mm,重现期均超100 a;水文过程模拟及典型断面洪水位分析结果表明,流域出口断面峰值流量达185.2 m3/s,洪水过程呈历时短、陡涨缓落的特点,水位迅速抬升形成漫滩洪水,最大陡涨率超1 m/h,极大限制了沿河居民避险转移时间;人类活动如围滩造地等行为严重侵占河道行洪面积,2000-2022年,流域居民用地增加160.3%,且沿(跨)河建筑物的阻水效应进一步阻碍行洪,加重了山洪灾害规模。On July 22,2023,Fuyang Distric of Hangzhou city of Zhejiang Province,was hit by a short-duration heavy rainfall,which induced a flash flood and caused casualties and property losses in the Shanxi River Watershed.To comprehensively understand the flash flood process and reveal the mechanism of flash flood in the affected area,the flash flood characteristics were analyzed from rainfall characteristics,flash flood process and human activities based on the field investigation data.The results show that short-term heavy rainfall is the main cause of the flash flood,with the maximum 1 h rainfall of 100.5 mm and the maximum 3 h rainfall of 150.0 mm at the site,and an over 100-year return period.The hydrological process simulation and flood level analysis of typical cross sections show that the peak flow rate of the basin outlet cross-section reaches 185.2 m3/s,and the flooding process is characterized by a short duration,steep rise and fall,and the water level is rapidly increased to form floodplain floods.The maximum steep rise rate exceeds 1 m/h,greatly limiting the time for residents along the river to avoid danger and transfer.Human activities such as land reclamation have seriously encroached on the flood discharge area of river.The land of residents increased by 160.3%from 2000 to 2022.The water blocking effect of buildings along(across)rivers further hindered flood discharge,exacerbating the scale of mountain flood disasters.

关 键 词：暴雨山洪 灾害调查 降雨特征 洪水分析 人类活动 剡溪小流域 

分 类 号：TV87[水利工程—水利水电工程] X43[环境科学与工程—灾害防治]