摘要
通过对珠江三角洲区有关水文泥沙资料的分析 ,初步揭示了西江和北江在流速与流量、水位、含沙量、断面宽深比之关系方面的差别。结合河道平面及断面形态和河道冲淤特性 ,探讨了其河型特点及成因。认为研究区西江为典型的网状河流 ,而北江仍处于网状河流的发育初期。该区网状河流多河道的形成遵循冲裂机制 ,人工堤围加速了河道沉积、抑制了河漫滩地的淤积 。
The relationships of velocity and discharge, water level elevation,sediment concentration and width-depth ratio of Xijiang and Beijiang River channels on the Zhujiang Delte area are analyzed and some differences between the two rivers are revealed. One of the differences is that the channel cross sections are different between the two rivers either in width-depth ratio or in channel evolution despite the planform of the two rivers appears multiple channel system. The author considered that all the Xijiang River channels and the Beijiang channels at B and C belts on the Delta area are anastomosing pattern, but the Beijiang River channels at A belt are not anastomosing river pattern. The Xijiang anastomosing channels are typical and developed, and the Beijiang anastomosing channels still are at the primary developing stage. The anastomosing channel formation follows the channel avulsion mechanism during flooding as Smith et al. (1989) stated. However, the frequency of channel avulsion is very rare, so the anastomosing channel formation has a long history. The anastomosing channels have cohesive natural levees that were consisted of fine grain sediment such as clay or mud. Artificial levees did not the formation cause of the anastomosing channel pattern. Nevertheless it not only restrained the migration of the channels and maintained the channel stability but also partly prevented flooding. This human behavior resulted the high sedimentary ratio in the anastomosing channels and lower sedimentary ratio on the interchannel lands. So the relative rising velocity of the anastomosing channel beds is greater than that of the interchannel lands.
出处
《沉积学报》
CAS
CSCD
北大核心
2002年第3期376-381,共6页
Acta Sedimentologica Sinica
基金
国家自然科学基金项目 (批准号 :40 1 0 1 0 0 3)
中科院地理科学与资源所知识创新工程领域前沿项目资助
关键词
北江三角洲
河道演变特征
水沙特点
网状河型
河道成因
西江三角洲
冲裂机制
hydrological and sediment characteristics,anastomosing river pattern, channel formation and evolution, lower Xijiang and Beijiang Rivers
