中文摘要：

白鹅潭位于广州市区西部，是珠江广州段水最深、河面最阔之处，前、后航道及流溪河交汇的节点，其特殊的地理区位和自然条件对广州市城市发展起着至关重要的作用。文章首先探讨珠江白鹅潭段河段卡口的地质地貌特征，利用近代地图及遥感图等数据，分析白鹅潭的河道演变及冲淤变化。结果表明，白鹅潭卡口河段的控制性作用对珠江水位的稳定具有重要的影响，白鹅潭段河床演变总体特征为河道缩窄较为明显，而淤浅相对较缓，卡口河段束窄，势必影响上游洪水下泄和缩减下游纳潮量。因此为保护珠江和广州城市的安全，应遵从河道演变规律，保证珠江卡口段两岸有较开阔的空间，不应再束窄江面。

英文摘要：

Baietan constraint reach of the Pearl River in Guangzhou, located in the west of downtown, is the deepest and widest water area in the city, with Front Channel, Back Channel and the Liuxi River converging here. Owing to its distinct location and physical conditions, Baietan plays a significant role in Guangzhou urban development. This paper discusses the geologic and geomorphologic features of the constrain reach, and then analyses its watercourse topographic evolution as well as scour-and-silting alternation based on ancient terrain map and remote sensing data. The result shows that Baietan reach plays a control role in stabilizing water level of the Pearl River, and its general evolution is characterized by evident narrowing but relatively slower shoaling. The narrowing of the reach would obstruct upstream flood discharge and reduce downstream tidal prism. Therefore, for protection of the Pearl River and the safety of the city, the evolutional law of the watercourse should be followed, the open space of the neck reach be maintained, and further narrowing of the river channel be avoided.