...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Earth Surface Processes and Landforms: The journal of the British Geomorphological Research Group >Assessing the effect of vegetation-related bank strength on channel morphology and stability in gravel-bed streams using numerical models
【24h】

Assessing the effect of vegetation-related bank strength on channel morphology and stability in gravel-bed streams using numerical models

机译：用数值模型评估与植被有关的河岸强度对砾石床河道形态和稳定性的影响

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Bank strength Clue to vegetation dominates the geometry of small stream channels, but has virtually no effect on the geometry of larger ones. The dependence of bank strength on channel scale affects the form of downstream hydraulic geometry relations and the meandering-braiding threshold. It is also associated with a lateral migration threshold discharge, below which channels do riot migrate appreciably across their floodplains. A rational regime model is used to explore these scale effects it parameterizes vegetation-related bank strength using a dimensionless effective cohesion, C-r*. The scale effects are explored primarily using all alluvial state space defined by the dimension less formative discharge, Q*, and channel slope, S, which is analogous to the Q-S diagrams originally used to explore meandering-braiding thresholds. The analyses show that the effect of vegetation on both downstream hydraulic geometry and the meandering-braiding threshold is strongest for the smallest streams in a watershed, but that the effect disappears for Q* > 10(6). The analysis of the migration threshold suggests that the critical discharge ranges from about 5 m(3)/s to 50 m(3)/s, depending on the characteristic rooting depth for the vegetation. The analysis also suggests that, where fires frequently affect riparian forests, channels may alternate between, laterally stable gravel plane-bed channels and laterally active riffle-pool channels. These channels likely do riot exhibit the classic dynamic equilibrium associated with alluvial streams, but instead exhibit a cyclical morphologic evolution, Oscillating between laterally stable and laterally Unstable end-members with a frequency determined by the forest fire recurrence interval.
机译：堤岸强度植被的线索主导着小河道的几何形状，但实际上对大河道的几何形状没有影响。堤岸强度对河道尺度的依赖性影响下游水力几何关系和弯曲编织阈值的形式。它还与横向迁移阈值排放有关，在该阈值以下，通道确实会在整个洪泛区发生暴动迁移。合理的制度模型用于探索这些尺度效应，它使用无因次有效内聚力C-r *参数化与植被相关的河岸强度。规模效应主要是通过所有由冲积状态空间Q *和通道斜率S定义的冲积状态空间来探索的，这与最初用于探索蜿蜒编织阈值的Q-S图相似。分析表明，对于分水岭中的最小水流，植被对下游水力几何学和弯曲编织阈值的影响最大，但对于Q *> 10（6）的影响消失。迁移阈值的分析表明，临界放电范围从大约5 m（3）/ s到50 m（3）/ s，这取决于植被的特征生根深度。分析还表明，在大火经常影响河岸森林的地方，河道可能在横向稳定的砾石平板河道和横向活跃的浅滩池河道之间交替。这些通道可能确实发生了暴动，表现出与冲积流相关的经典动态平衡，但表现出周期性的形态演化，以森林火灾的复发间隔确定的频率在横向稳定端和横向不稳定端构件之间振荡。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号