Author(s): Huai-Xiang Liua; Zhao-Yin Wangb; Yong-Jun Lua; Guo-An Yuc
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Keywords: Streambed structures; Stream power; Equilibrium; Geomorphology
Abstract: Streambed structures were developed in many very coarse gravel-bed rivers as a result of fluvial morphology. And the distribution of them was obviously relevant with environment conditions. This paper carried out field investigations in natural rivers, to study the streambed structures’size, distribution in the basin, as well as their connections with local environmental conditions. A field experiment was also conducted to study the evolution and function of structures. The results of both investigations and the experiment indicated that: The streambed structures can enhance resistance to water erosion and protect riverbed. Given the conditions of little bedload, the structure intensity is in direct ratio to the unit-width stream power which consumed by the structures when rivers are in dynamic equilibrium. If the structures are not able to dissipate the whole power, the river status turns to disequilibrium and the riverbed will be eroded by excess energy. The fluvial morphology of coarse-grained riverbed is controlled by this process. A unified power consumption model including bedload transportation was also discussed. Furthermore, the streambed structures could control retrogressive erosion, determine channel profiles and influence river geomorphology.
Year: 2012