Spatial Variations of Channel Patterns
-
摘要: 论述了现代冲积河流系统中常见河型的自然分布及转化特征,归纳了河型从上游向下游发生空间转化的 5种主要模式。这些河型转化模式发生的相对频率是不同的,其中从辫状河流向曲流河流转化的发生频率最大。文中通过具体实例总结了这些转化模式分别发生时的主要影响因素。Abstract: The formation of channel patterns and its characteristics are important aspects in modern and ancient fluvial system studies, and thus become the main concern for hydraulic engineers, geomorphologists and sedimentologists. So far, there are still some questions not clear in this area, for example, the classification of channel patterns, formation cause of anastomosing fluvial rivers, critical conditions of evolution of some fluvial channel patterns, and further studies are still needed. Another problem related to channel pattern is the transformation of the patterns. In the present paper, four ordinary patterns are discussed, which include the braided, meandering, anabranched (in which include the anastomosing) and straight patterns. Comprehensive study to the spatial transformation of above channel patterns has significance not only for management of modern river and prevention of flood,but also for prospect and exploitation for hydrocarbon and some mineral resources in ancient fluvial depositional systems. The spatial longitudinal variations of river patterns not only show the characteristics of individual channel patterns, but also the transformation between the patterns. The different transformation will shadow different characteristics and consenguencies, but the same transformation has definite general characters and analogous controlling factors. In this paper, the spatial transformation models of fluvial channel patterns and its influences are discussed. Five conceptual models for the spatial transformation of river channel patterns are presented, which include the models of "Braided-Meandering", "Straight-Meandering", "Meandering-Braided", "Meandering-Anabranched" and "Anabranched-Straight". Although the possible spatial transformations among the braided, meandering, anabranched and straight fluvial channel patterns possibly occur in nature, the others except above five in 12 possible transformations have not been observed so far. Furthermore, each one of the five models has different occurring frequency, the model of "Braided-Meandering" occurs generally in larger frequency. The 5 types of transformations are elucidated and interpreted in terms of various examples. The driven factors that control the trend of transformation are also discussed in details. In general, the transformations determined by the integration of geotectonics, climate, vegetation, river valley slope, bank sediment composition and hydraulic factors, but their influence to each type of the models are different.
-
Key words:
- channel patterns /
- model of spatial variations /
- controlling factors
-
[1] 倪晋仁，张仁.河型成因的各种理论及其间关系[J].地理学报，1991，46(3)：366～372 [2] 陆中臣，舒晓明.河型及其转化的判别[J].地理研究，1988，7(2)：7～16 [3] 尹学良.弯曲性河流形成原因及造床试验初步研究[J].地理学报，1965，31(4)：287～303 [4] 尤联元，洪笑天，陈志清.影响河型发育几个主要因素的初步探讨[A].见：第二届河流泥沙国际学术讨论会论文集（中国南京）[C].北京：水利水电出版社，1983.662～672 [5] 尤联元，叶青超，金德生.中国河流地貌研究现状和展望[A] ，见：中国地理学会地貌与第四纪专业委员会（编），地貌及第四纪研究进展[C].北京：测绘出版社，1991.8～15 [6] 罗海超，周学文，尤联元等.长江中下游分汊河型成因研究[A].河流泥沙国际学术讨论会论文集，光华出版社，1980.447～456 [7] 蔡强国.地壳构造运动对河型转化影响的实验研究[J].地理研究，1982，1(3)：21～32 [8] Lane E W. A study of the shape of channels formed by natural streams flowing in erodible material[A]. M. R. D. Sediment Series No. 9, Missouri River Div., Corps Engrs.,1957. 106 [9] Leopold L B， Wolman M G, River channel patterns, braided, meandering and straight, U. S. Geol[A]. Surv. Paper.1957. 282 [10] Schumm S A. Fluvial geomorphology： historical perspoctive[A]. In： Shen H W，ed.River Mechanics[C] , Collins, Colorado，1971 [11] Gole C V，Chaitale S V. Inland delta building activity of Kosi River[J]. J. Hyd. Div., Proc. Amer. Soc. Civil Engrs.,1966， 92 (HY)： 111～126 [12] Stevens M A，Simons D B， Richardson E V. Nonequilibrium River form[J]. J. Hyd. Div., Proc. Amer. Soc. Civil Engrs., 1975，101(HY5)： 557～566 [13] 钱宁，张仁，周志德.河床演变学[M].北京：科学出版社，1987.584 [14] 大港油田地质研究所，海洋石油勘探局研究院，同济大学海洋地质研究所.滦河冲积扇—三角洲沉积体系[M].北京：地质出版社，1985.164 [15] Brice G C. Channel pattern and terraces of the Loup Rivers in Nebraska[R]. U. S. Geol. Survey Prof. Paper No. 422-D, 1964.41 [16] 倪晋仁，马蔼乃.河流动力地貌学[M].北京：北京大学出版社，1998.396 -
点击查看大图
计量
- 文章访问数: 646
- HTML全文浏览量: 8
- PDF下载量: 466
- 被引次数: 0
下载:
