When analyzing the physical habitat in a river, it is necessary to understand its structure hierarchically. This paper focuses on a riffle structure in a middle reach of a river. Firstly, as a unit scale analysis, we classified the riffles based on its plane shape. Plane shape of a riffle is determined by the condition of sandbar that is affected by the amount of transported sediment. And plane shape of a riffle determines the distribution of local discharge in a riffle. Next, as a subunit analysis, we clarified the typical distribution pattern of longitudinal and lateral gradient of riverbed and gravel structure in a riffle. And the distribution of longitudinal and lateral gradient of riverbed is determined by the common feature of sandbar shape. Finally, as a point scale analysis, we showed the examples of wave pattern on each subunit. Wave pattern is related to the hydraulic conditions, so it represents the habitat condition for fishes, macro invertebrates and attached algae. Based on this analysis, it is possible to understand the microhabitat condition in relation to the amount of sediment, river shape, and scale of floods that can be controlled in river management.
Hierarchical analysis of physical environment in riffles
KSCE J Civ Eng
KSCE Journal of Civil Engineering ; 9 , 1 ; 1-6
2005-01-01
6 pages
Article (Journal)
Electronic Resource
English
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