西江防洪堤建成后洪水频率变化影响分析  

Analysis of impact on flood frequency change after construction of Xijiang River flood protection dike

作　　者：朱颖洁 ZHU Ying-jie(Hydrology Center of Wuzhou City,Wuzhou 543002,China)

机构地区：[1]梧州水文中心,广西梧州543002

出　　处：《广西水利水电》2023年第1期83-86,共4页Guangxi Water Resources & Hydropower Engineering

基　　金：广西自然科学基金项目(桂科基0991026);广西水利厅科技项目(201618)。

摘　　要：结合西江流域水文资料,基于洪水遭遇频率计算研究西江防洪堤建设对洪水频率的影响。首先采用有序聚类法和秩和检验法找出梧州水文站年最大流量序列的突变点;接着选用对数正态分布、P-Ⅲ型分布和Gumbel分布拟合防洪堤建设前后的年最大流量序列,并采用柯尔莫洛夫-斯米尔诺夫(KS)方法检验理论分布与经验分布的偏离程度,选出最合理的拟合分布;最后分析防洪堤建成后西江洪水的频率变化及洪水遭遇的概率变化。结果表明:对于相同的年最大流量,防洪堤建成后频率变大,重现期变小;对于相同的频率和重现期,防洪堤建成后相应的年最大流量变大;防洪堤修建前后西江发生大洪水时,浔江与桂江同时发生大洪水的概率并不高;当西江发生大洪水时,浔江出现较大洪水的概率较高;在防洪堤影响下洪水遭遇的概率发生了较大的变化:西江发生洪水的条件下,防洪堤建成后洪水遭遇的概率变小。Combined with the hydrological data of Xijiang River basin and based on the frequency calculation of flood encounters, the author studied the impact of the construction of Xijiang flood protection dike on flood frequency. First, ordered clustering method and rank sum test were adopted to find out the mutation point of the annual maximum flow sequence of Wuzhou Hydrological Station. Second, lognormal distribution, P-III distribution and Gumbel distribution were selected to fit the annual maximum flow sequence before and after the construction of flood dike,and the most reasonable fitting distribution was selected after testing the deviation degree of theoretical distribution and empirical distribution by Kormolov-Smirnov(KS) method. Finally, the changes of Xijiang River flood frequency and flood encounter probability after the construction of flood dike were analyzed. The results of analysis show that for the same annual maximum flow, the frequency becomes higher and the recurrence period becomes shorter after flood dike construction;for the same frequency and recurrence period, corresponding annual maximum flow becomes larger after flood dike construction;before and after dike construction, when a big flood occurs in Xijiang River, the probability of big floods also occurring at the same time in Xunjiang River and Guijiang River is not high, but the probability of a relatively big flood occurring in Xunjiang River is relatively high;under the impact of flood dike,the probability of flood encounter changes significantly and becomes smaller in case of flood occurring in Xijiang River.

关 键 词：洪水频率 洪水遭遇 Gumbel分布 防洪堤 西江 梧州 

分 类 号：P333.2[天文地球—水文科学]