摘要
淮河干支流弯曲河型十分发育.本文从水沙条件、地貌部位、河岸结构及组成物质、局部基准面的控制作用等方面,对于淮河弯曲河型的成因进行了初步探讨.同时还根据演变动态的不同将弯曲河型趔分为三个亚型,并讨论了各亚型的形成条件.
The Huaihe River and its main tributaries have well developed meandering channels. The controlling factors for this have been dealt in this paper, which can be summerized as follows:l.Hydrological and sediment load factors. By plotting sediment load, Qs against water discharge, Q, it was found out that all the data points could be divided into 3 belts which represent stable braided river pattern, meandering river pattern and wandering river pattern, respectively. It is notable that all the points representing the Huaihe River and its tributaries are situated within the meandering river pattern belt. The Huaihe River's exponent b in Qs-Qb relation is rather large, meaning that its water discharge-sediment load relation is characterized by high water associated by heavy sediment load and low water associated by low sediment load. This gives a large height difference between floodplain surface and bed bottom, which is conducive to the formation of meanders.2.Landform units which the rivers pass through. The Huaihe River and its many tributaries are situated in the southeast marginal zone of the Yellow River alluvial fan. This location makes them a very low valley slope and therefore a very low energy expenditure per unit length of river valley, which tends to the formation of meanders.3.Resistivity of boundary materials to erosion. Due to the spatial differentiation of depositional process on the Yellow River alluvial fan, the clay content in the bank materials of the Huaihe River and its tributaries is rather high, and the relative thickness of fine-grained upper part of the double layered bank is large, leading to a strong resistivity of river bank to erosion, which is favourable to meander development.4.Influence of the Hongzhehu Lake as a local base level. Due to the long-term human activities in history, this lake took shape and expanded sharply. The continuous rise of the lake's water stage means a rise of local base level. Accordingly, the river channel gradient became gentler, and more fine sediment such as silt and clay could be deposited in the channel boundary, making the river channel more sinuous.In addition, based on the data of the Huaihe River and its tributaries, meandering river channel pattern has been classified into 3 sub-patterns, their formation conditions being discussed in the paper.
出处
《泥沙研究》
CSCD
北大核心
1989年第2期1-11,共11页
Journal of Sediment Research
