作为调蓄城市洪水的主要工程手段, 城市上游水库和城市河道整治工程在保护沿岸居民不受侵害的同时, 也 改变了天然河道洪水槽蓄关系, 再加上气候变化的影响, 导致城市洪水的形成、演变及时空分布规律发生了变异。 利用水文变异诊断系统和谢才2曼宁公式, 分析了宣恩城区变化环境下洪水的变异形式、程度及其成因。结果发现: 1956 年- 2010 年面平均年最大月雨量序列在1998 年发生了跳跃向下的中变异, 说明气候变化影响下降雨呈减少 趋势; 宣恩站实测年最大日流量序列在1999 年发生了跳跃向下的中变异, 其洪峰流量呈减少趋势; 流域洪水变异是 气候变化和人类活动双重影响的结果, 但前者影响仅为后者的41%; 渠化改造导致宣恩站洪水流量减少, 加剧了洪 水变异, 因此其防洪预警预案需要适应环境变化而进行调整。

As themain engineer ing means o f contr olling urban flood, riv er and upst ream r eser vo ir reg ulatio ns which pr otect people against flo od disaster s can chang e r iver channel stor age and lead to the var iatio ns of the formatio n, evo lutio n, and spatial and tempo ral distributio n of urban flo od due to climate chang e. In this st udy, hydrolog ical var iatio n diagnosis system and the fo rmula of Ch?zy2manning w ere used to determine the f loo d var iation fo rm, degree, and causes of Xuanen dist rict under the chang ing en2 v iro nment. The results show ed that ( 1) the aver age annual max imum monthly rainfall ser ies f rom 1956 t o 2010 have a mo derat e variatio n w ith downw ard jump in 1998, which indicates t hat rainfall decreases under the chang ing env iro nment; ( 2) the annual maximum daily flow series from 1962 to 2013 have a moder ate v ariation with dow nw ard jump in 1999, which indicates that peak flow decr eases; ( 3) The dual effects of climate chang e and human activ ities cause the flo od variation, but the former effects ar e only 41% o f the lat ter; and ( 4) riv er cana lizatio n r esult s in the decreasing o f t he flood flow and exacer bation of flo od v ariation, ther efor e t he flood w arning plan needs to adapt to the chang ing environment .

国家自然科学基金资助项目( 51190094; 50979075; 51179131) ; 广东省水利科技创新项目成果( 2011201)