珠江三角洲腹地洪水特征变异因素的关联分析

CORRELATION ANALYSIS ON ABNORMAL CHANGE OF FLOOD LEVEL IN THE CENTRAL AREA OF THE PEARL RIVER DELTA

采用关联分析法 ,对珠江三角洲网河区腹地代表站近期洪水位变异的各种成因的主次作用进行分析 ,结果表明 ,近期导致腹地洪水位异变的主要因素依次是 ,河口水流不畅和潮流顶托、西江向三角洲腹地河网分流以及三角洲网河上部水情。三角洲河口水流顶托与上游分流增加、流速加快 (均与人类活动造成的河床变异有关 )在腹地形成“水流挤压”共同导致腹地的异高洪水位 ;同时 ,三角洲腹地河滩占用严重 ,桥梁、码头建设密度大 ,更加剧了腹地河道水位壅高。

There are many factors affecting the hydrological change in the central area of the Pearl River Delta(PRD), e.g., the change of upstream inflow, the rise of sea level, the man induced change of river bed and the change of runoff caused by the climatic variables, among which the first 3 are the key ones to be considered. With the specific gage data, the factors acting on the change of flood in the central area of the PRD is studied by correlation analysis. The results show that the factors contributing to the change of flood in the central PRD are as follows in order of importance: the back water effects at the river mouth due to sedimentation and rising of sea level, the increase of discharge distributed from the Xijiang River to the river network of the Delta, and the upstream hydrological conditions. The combined effects of those factors make the flood water in the central PRD pile up, and anomalous high water level occurs. At the same time, the dense sluices, bridges and docks along the river and the change of land use in the Delta all contribute to the rise of water level.