期刊
GEOMORPHOLOGY
卷 417, 期 -, 页码 -出版社
ELSEVIER
DOI: 10.1016/j.geomorph.2022.108444
关键词
Ephemeral stream; Drylands; Large wood; Sediment dynamics; Flash flood
资金
- U.S. National Science Foundation Graduate Research Fellowship Program
Compared to perennial streams, there is a lack of studies investigating the impact of large wood on sediment transport and river corridor morphology in ephemeral streams. Both large wood and vegetation effectively confine flow to the main channel, causing it to become wider and deeper. Large wood enhances channel change caused by vegetation, but vegetation has a greater influence on channel morphology due to its larger area within the stream corridor.
Compared to perennial streams, studies investigating the impact of large wood on sediment transport and river corridor morphology in ephemeral streams are lacking. Due to the flashy nature of ephemeral flow regimes, opportunities to directly investigate the influence of wood in ephemeral channels are limited. Additionally, given prior studies showing a strong association between existing riparian vegetation and large wood deposition in ephemeral streams, the geomorphic impact of wood is entangled with that of vegetation. Here, we develop a hydro-morphodynamic model to investigate changes to channel and floodplain morphology due to wood and vegetation in an ephemeral stream in southeastern Arizona, USA. Three scenarios are modeled: the actual configuration of the river corridor; an experiment in which jams are removed; and an experiment in which vegetation is removed. Both large wood and vegetation effectively confined flow to the main, unvegetated channel, which became wider and deeper over the course of a single moderate flood. When isolating the impact of large wood, model results show that wood enhances channel change created by vegetation, resulting in & PLUSMN;0.1 to 0.3 m of additional scour or aggradation. The simulated removal of vegetation resulted in more channel change than the removal of wood alone, partially because vegetation occupies a much greater area within the stream corridor than large wood. We propose a conceptual framework where large wood could mediate sedimentation as well as the recruitment and growth of vegetation in ephemeral streams, contributing to the evolution of ephemeral stream morphology over time.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据