Estimating River Channel Bathymetry in Large Scale Flood Inundation Models
Estimating River Channel Bathymetry in Large Scale Flood Inundation Models
复制标题
估算大规模洪水淹没模型中的河道测深
DOI：
--
复制
发表时间：
2021
影响因子：
5.4
通讯作者：
C. Sampson
中科院分区：
文献类型：
--
作者：
J. Neal;Laurence Hawker;J. Savage;M. Durand;P. Bates;C. Sampson
近年来，由于希望为更广泛的地点提供危险信息，跨大型数据稀疏地区的洪水淹没建模一直在增加。由于遥感和建模能力的提高，这些模型的复杂性在过去十年中稳步提高。现在有几个全球洪水模型(GFMS)，它们试图模拟所有河流和泛滥平原的水面动态，而不考虑数据的稀缺。然而，数据稀疏地区的洪水模型缺乏河流水深测量，因为这不能远程观测，这意味着从均匀流或下游水力几何理论发展了各种近似河流水深测量的方法。我们认为，这些模型中的水深估算应遵循渐变流动理论，以考虑均匀和非均匀流动。我们证明，现有的GFMS水深估算方法只适用于运动水面剖面，不能模拟具有扩散或浅水波特性的河段的无偏水面剖面。在GFM中使用渐变流理论来估计水深，与目标水面剖面相比，模型误差减少了66%，并消除了回水效应造成的偏差。对于莫桑比克的一个大型测试案例，这在5年重现期内将洪水范围减少了40%，洪泛区的蓄水量减少了79%。与均匀流导出的渠道相关的湿偏差可能会对模拟泛滥平原在减弱河流排放方面所起的作用产生重大影响，可能会夸大它们的作用。
Flood inundation modeling across large data sparse areas has been increasing in recent years, driven by a desire to provide hazard information for a wider range of locations. The sophistication of these models has steadily advanced over the past decade due to improvements in remote sensing and modeling capability. There are now several global flood models (GFMs) that seek to simulate water surface dynamics across all rivers and floodplains regardless of data scarcity. However, flood models in data sparse areas lack river bathymetry because this cannot be observed remotely, meaning that a variety of methods for approximating river bathymetry have been developed from uniform flow or downstream hydraulic geometry theory. We argue that bathymetry estimation in these models should follow gradually varying flow theory to account for both uniform and nonuniform flows. We demonstrate that existing methods for bathymetry estimation in GFMs are only accurate for kinematic water surface profiles and are unable to simulate unbiased water surface profiles for reaches with diffusive or shallow water wave properties. The use of gradually varied flow theory to estimate bathymetry in a GFM reduced model error compared to a target water surface profile by 66% and eliminated bias due to backwater effects. For a large‐scale test case in Mozambique this reduced flood extents by 40% and floodplain storage by 79% at the 5 years return period. The wet bias associated with uniform flow derived channels could have significant implications for modeling the role floodplains play in attenuating river discharges, potentially overstating their role.
登录
查看更多内容
影响因子：
12.1
作者：
J. Lewin;P. Ashworth
通讯作者：
J. Lewin;P. Ashworth
影响因子：
6.3
作者：
F. Pappenberger;E. Dutra;F. Wetterhall;H. Cloke
通讯作者：
F. Pappenberger;E. Dutra;F. Wetterhall;H. Cloke
影响因子：
13.5
作者：
S. Biancamaria;M. Durand;K. Andreadis;P. Bates;A. Boone;N. Mognard;E. Rodríguez;D. Alsdorf;D. Lettenmaier;E. Clark
通讯作者：
S. Biancamaria;M. Durand;K. Andreadis;P. Bates;A. Boone;N. Mognard;E. Rodríguez;D. Alsdorf;D. Lettenmaier;E. Clark
影响因子：
5
作者：
R. Emerton;H. Cloke;A. Ficchí;Laurence Hawker;Sara de Wit;L. Speight;C. Prudhomme;Philip Rundell-Philip-Rundel
通讯作者：
R. Emerton;H. Cloke;A. Ficchí;Laurence Hawker;Sara de Wit;L. Speight;C. Prudhomme;Philip Rundell-Philip-Rundel
影响因子：
6.4
作者：
Garcia-Pintado, Javier;Mason, David C.;Bates, Paul D.
通讯作者：
Bates, Paul D.