首页> 外文OA文献 >Quantifying the combined effects of multiple extreme floods on river channel geometry and on flood hazards
【2h】

Quantifying the combined effects of multiple extreme floods on river channel geometry and on flood hazards

机译:量化多次极端洪水对河道几何形状和洪水灾害的综合影响

代理获取
本网站仅为用户提供外文OA文献查询和代理获取服务,本网站没有原文。下单后我们将采用程序或人工为您竭诚获取高质量的原文,但由于OA文献来源多样且变更频繁,仍可能出现获取不到、文献不完整或与标题不符等情况,如果获取不到我们将提供退款服务。请知悉。

摘要

Effects of flood-induced bed elevation and channel geometry changes on flood hazards are largely unexplored, especially in the case of multiple floods from the same site. This study quantified the evolution of river channel and floodplain geometry during a repeated series of hypothetical extreme floods using a 2D full hydro-morphodynamic model (LHMM). These experiments were designed to examine the consequences of channel geometry changes on channel conveyance capacity and subsequent flood dynamics. Our results revealed that extreme floods play an important role in adjusting a river channel to become more efficient for subsequent propagation of floods, and that in-channel scour and sediment re-distribution can greatly improve the conveyance capacity of a channel for subsequent floods. In our hypothetical sequence of floods the response of bed elevation was of net degradation, and sediment transport successively weakened even with floods of the same magnitude. Changes in river channel geometry led to significant impact on flood hydraulics and thereby flood hazards. We found that flood-induced in-channel erosion can disconnect the channel from its floodplain resulting in a reduction of floodwater storage. Thus, the frequency and extent of subsequent overbank flows and floodplain inundation decreased, which reduced downstream flood attenuation and increased downstream flood hazard. In combination and in summary, these results suggest that changes in channel capacity due to extreme floods may drive changes in flood hazard. The assumption of unchanging of river morphology during inundation modelling should therefore be open to question for flood risk management.
机译:洪水引起的河床高程和河道几何形状变化对洪水危害的影响在很大程度上尚待探索,特别是在同一地点发生多次洪水的情况下。这项研究使用二维全水动力模型(LHMM)对一系列假设性极端洪水的重复序列进行量化,量化了河道和洪泛区几何的演变。这些实验旨在检查通道几何形状变化对通道输送能力和后续洪水动力学的影响。我们的结果表明,极端洪水在调节河道以使其更有效地用于随后的洪水传播中起着重要作用,并且河道内冲刷和沉积物的重新分配可以大大提高随后洪水的河道的输送能力。在我们假设的洪水序列中,河床高程的响应是净退化,即使有相同规模的洪水,沉积物的输送也逐渐减弱。河道几何形状的变化导致对洪水水力的重大影响,从而导致洪水灾害。我们发现洪水诱发的河道内侵蚀可以使河道与其洪泛区断开连接,从而导致洪水蓄水量减少。因此,随后的溢流和洪泛区泛滥的频率和程度降低了,这减少了下游洪水的衰减并增加了下游洪水的危害。总之,这些结果表明,由于极端洪水而导致的河道容量变化可能会导致洪水灾害的变化。因此,在洪水泛滥模型中河流形态不变的假设对于洪水风险管理应该是值得商question的。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
代理获取

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