Repeated high flows drive morphological change in rivers in recently deglaciated catchments
Repeated high flows drive morphological change in rivers in recently deglaciated catchments
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反复出现的高流量导致最近冰川消融的流域河流形态发生变化
DOI：
10.1002/esp.5098
复制
发表时间：
2021
影响因子：
3.3
通讯作者：
Eagle L
中科院分区：
文献类型：
--
作者：
Eagle L
在世界许多地区，气候变化正在减少冰川覆盖，并增加由降水驱动的大流量和洪水的频率和强度。在近期冰川消融的流域，降水可能成为河流系统的主要水源，主要降雨事件会导致河道形态的显著变化。然而，很少有研究考察了河道对反复降水驱动的高流量的响应。在这项研究中，我们测量了2014年夏季一系列反复降水驱动的大流量前后的四条低阶河流的地貌状况，这些河流位于最近冰川消退的流域（70-210年无冰）。高流量驱动了大量的初始形态变化，从高流量前到高流量后，基流通道平台位置和活动通道形态的变化高达75%。除了最年轻的河流外，高流量后的年份与河流木材和地貌复杂性的增加有关。河道变化是所有河流主动松弛阶段的一部分，河道继续迁移，复杂程度随时间而变化。总的来说，这些测量结果使我们能够在副冰川调整理论的背景下提出地貌有效高流量作用的概念模型。具体来说，我们认为在最近冰川消融的流域中，由于河流木材的补充和反复降水驱动的高流量期间和之后的河道迁移，较老的河流可能会经历一个短期（<10年）的地貌发育速度增加。在快速变化的环境中，提高我们对这些应对高流量的地貌和副冰川过程的认识对于有效管理河流水和生态系统资源非常重要。
Climate change is decreasing glacier cover and increasing the frequency and magnitude of precipitation‐driven high flows and floods in many regions of the world. Precipitation may become the dominant water source for river systems in recently deglaciated catchments, with major rainfall events driving significant changes in river channel morphology. Few studies, however, have examined river channel response to repeated precipitation‐driven high flows. In this study, we measured the geomorphological condition of four low‐order rivers in recently deglaciated catchments (70–210 years ice free) before and after a series of repeated precipitation‐driven high flows during summer 2014. High flows drove substantial initial morphological change, with up to 75% change in baseflow channel planform position and active channel form change from pre‐ to post‐high flow. Post‐high flow years were associated with increased instream wood and geomorphological complexity at all but the youngest river. Channel changes were part of an active relaxation stage at all rivers, where channels continued to migrate, and complexity varied through time. Overall, these measurements permit us to propose a conceptual model of the role of geomorphologically effective high flows in the context of paraglacial adjustment theory. Specifically, we suggest that older rivers in recently deglaciated catchments can undergo a short‐term (<10 years) increase in the rate of geomorphological development as a result of the recruitment of instream wood and channel migration during and following repeated precipitation‐driven high flows. Enhancing our knowledge of these geomorphological and paraglacial processes in response to high flows is important for the effective management of riverine water and ecosystem resources in rapidly changing environments.
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影响因子：
3.3
作者：
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影响因子：
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作者：
D. Brogan;P. Nelson;L. Macdonald
通讯作者：
L. Macdonald
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DOI：
--
发表时间：
2003
期刊：
影响因子：
--
作者：
D. Montgomery;B. Collins;J. Buffington;T. Abbe
通讯作者：
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DOI：
10.3133/sir20165024
发表时间：
2016
期刊：
Scientific Investigations Report
影响因子：
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作者：
Janet H. Curran;N. Barth;Andrea G. Veilleux;R. Ourso
通讯作者：
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