On Debris Flows, River Networks, and the Spatial Structure of Channel Morphology
On Debris Flows, River Networks, and the Spatial Structure of Channel Morphology
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DOI：
10.1093/forestscience/53.2.220
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发表时间：
2007-04
期刊：
影响因子：
1.4
通讯作者：
Paul E. Bigelow;L. Benda;Dave Miller;K. Burnett
中科院分区：
文献类型：
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作者：
Paul E. Bigelow;L. Benda;Dave Miller;K. Burnett
我们评估了俄勒冈海岸中部更大的含鱼河道中源头溪流的泥石流的形态影响，包括它们对扇子、木材补充和河道形态的影响。在三至五级河流(流域面积10平方公里，坡度7%)上进行了6.4公里的连续河道调查，这些河流在汇合处的碎屑扇效应最明显。这个盆地的大小包含了中央海岸范围内的大部分河道(67%)，其坡度为Coho鲑鱼(Oncorhynchus Kisutch Walbaum)所用。易受泥石流影响的源头支流之间的间距很小(平均118米)，导致连续的长段含鱼溪流被泥石扇(平均103米)和泥石扇冲击，占所调查河道总长度的54%。泥石流还为所调查的载鱼河道提供了大部分木材(58%)。大型木材、巨石和河道坡度的最高值与源头支流汇合处的碎屑扇有关，而较深的沉积物沉积往往与扇有关，但也与扇的上下游延伸有关。泥石流发源地支流的间距和网络格局影响着河道形态和水生生境的空间结构，导致河道环境具有高度的物理异质性和斑块性。我们的研究有助于日益重视支流汇流在山地流域河流形态和水生生境结构中的作用，并主张在河流分类和栖息地分类方案中纳入汇流部分。
We evaluated the morphological effects of debris flows from headwater streams in larger, fish-bearing channels of the central Oregon Coast Range, including their influence on fans, wood recruitment, and channel morphology. Continuous channel surveys (6.4 km) were conducted in third- through fifth-order streams (drainage area <10 km2 and slope <7%) where debris fan effects at confluences were most evident. This basin size contains the majority of channels (67%) in the central Coast Range with gradients that are used by coho salmon (Oncorhynchus kisutch Walbaum). The close spacing between headwater tributaries susceptible to debris flows (118 m average) resulted in long continuous sections of fish-bearing streams that were bordered by debris fans (103 m average) and debris fans impinging on 54% of the total channel length surveyed. Debris flows also supplied the majority of wood (58% of pieces) to the surveyed fish-bearing channels. The highest values of large wood, boulders, and channel gradients were associated with debris fans at confluences with headwater tributaries, while deeper sediment deposits were often associated with fans but also extended up and downstream from fans. The spacing and network pattern of debris flow-prone headwater tributaries influenced the spatial structure of channel morphology and aquatic habitats leading to a high degree of physical heterogeneity and patchiness in channel environments. Our study contributes to a growing emphasis on the role of tributary confluences in structuring channel morphology and aquatic habitats in mountain drainage basins and argues for including a confluence component to stream classification and habitat typing schemes.