Dynamic flood topographies in the Terai region of Nepal
Dynamic flood topographies in the Terai region of Nepal
复制标题
尼泊尔特莱地区的动态洪水地形
DOI：
10.1002/esp.4953
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发表时间：
2020
影响因子：
3.3
通讯作者：
Dingle E
中科院分区：
文献类型：
--
作者：
Dingle E
用于向尼泊尔南部Terai地区偏远社区提供信息和建立复原力的洪水风险地图基于过时的静态数字高程模型(DEM)，这些模型没有反映动态的河流配置或水文学。河道的阶段性变化、泥沙动力学和沿大分叉节点的水流分布可以改变该地区的洪水程度，但在洪水风险评估中很少考虑这些过程。在这里，我们建立了尼泊尔西部Terai地区Karnali河的2D水动力洪水模型。测试了许多场景，检查不同的DEM，改变床层高度来模拟床层堆积和切割，并在一个大的分叉节点更新床层高程以反映现场观察。通过改变模型中使用的DEM的年龄，观察到20年的洪水淹没程度增加了9.5%。仅降低水平DEM分辨率就会导致1%的变化。均匀改变河床高程导致淹没程度变化36%。最后，主分支处河床高程的变化反映了观测条件，导致大部分水流分流到西支流，这与两个支流之间的实测流量比一致，淹没程度变化了32%。虽然洪水淹没总面积有所减少(−为4%)，但西岸地区的淹没面积有所增加。我们的结果表明，在大型泥沙产生事件后，以及在大型河流分叉等地形敏感区域，定期进行河床高程测量和更新DEM，可以帮助改进未来洪水预测模型的模型输入。在洪水事件将大量泥沙从山区带出后，这一点尤其重要，这可能会促进下游人口稠密的冲积河流系统和泛滥平原的河床淤积和河道改道。©2020作者。约翰·威利父子有限公司出版的地球表面过程和地貌
Flood hazard maps used to inform and build resilience in remote communities in the Terai region of southern Nepal are based on outdated and static digital elevation models (DEMs), which do not reflect dynamic river configuration or hydrology. Episodic changes in river course, sediment dynamics, and the distribution of flow down large bifurcation nodes can modify the extent of flooding in this region, but these processes are rarely considered in flood hazard assessment. Here, we develop a 2D hydrodynamic flood model of the Karnali River in the Terai region of west Nepal. A number of scenarios are tested examining different DEMs, variable bed elevations to simulate bed aggradation and incision, and updating bed elevations at a large bifurcation node to reflect field observations. By changing the age of the DEM used in the model, a 9.5% increase in inundation extent was observed for a 20‐year flood discharge. Reducing horizontal DEM resolution alone resulted in a <1% change. Uniformly varying the bed elevation led to a 36% change in inundation extent. Finally, changes in bed elevation at the main bifurcation to reflect observed conditions resulted in the diversion of the majority of flow into the west branch, consistent with measured discharge ratios between the two branches, and a 32% change in inundation extent. Although the total flood inundation area was reduced (−4%), there was increased inundation along the west bank. Our results suggest that regular field measurements of bed elevation and updated DEMs following large sediment‐generating events, and at topographically sensitive areas such as large river bifurcations, could help improve model inputs in future flood prediction models. This is particularly important following flood events carrying large sediment loads out of mountainous regions that could promote bed aggradation and channel switching across densely populated alluvial river systems and floodplains further downstream. © 2020 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd
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砾石-沙过渡区的沉积物动态：对河流稳定性和洪泛区回收的影响
影响因子：
5.8
作者：
Gautam D
通讯作者：
Gautam D
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DOI：
--
发表时间：
2013
期刊：
影响因子：
--
作者：
N. Rana;Sunil Kumar Singh;Y. Sundriyal;N. Juyal
通讯作者：
N. Juyal
影响因子：
3.3
作者：
Daniel R. Parsons;P. R. Jackson;J. Czuba;F. Engel;B. Rhoads;Kevin A. Oberg;James L. Best;David S. Mueller;Kevin K. Johnson;James D. Riley
通讯作者：
Daniel R. Parsons;P. R. Jackson;J. Czuba;F. Engel;B. Rhoads;Kevin A. Oberg;James L. Best;David S. Mueller;Kevin K. Johnson;James D. Riley
影响因子：
18.3
作者：
Constantine, Jose Antonio;Dunne, Thomas;Lazarus, Eli D.
通讯作者：
Lazarus, Eli D.
影响因子：
3.9
作者：
Dingle E
通讯作者：
Dingle E