The influence of floodplain restoration on flow and sediment dynamics in an urban river
The influence of floodplain restoration on flow and sediment dynamics in an urban river
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DOI：
10.1111/jfr3.12251
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发表时间：
2018-02
影响因子：
4.1
通讯作者：
S. Ahilan;Mingfu Guan;A. Sleigh;Nigel G. Wright;Heejun Chang
中科院分区：
文献类型：
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作者：
S. Ahilan;Mingfu Guan;A. Sleigh;Nigel G. Wright;Heejun Chang
本文对最近恢复的河漫滩进行了河漫滩沉积研究。本研究使用二维水文形态动力学模型来预测约翰逊河下游的流动和悬浮泥沙动力学，东Lents河段，在那里，河岸被重新配置，重新连接到0.26平方公里（26公顷）的恢复洪泛平原。模拟情景包括基于10年、50年、100年和500年事件的洪水事件沉积模型，以及使用1941年至2014年之间64个历史洪水事件的长期模型。模拟结果表明，恢复后的河漫滩使上游洪峰在下游显著减弱，减弱幅度达25%。结果还表明，上游约有20%-30%的泥沙沉积在东Lents泛滥平原上。此外，在模拟期间（1941-2014年）沉积的泥沙约占流域储洪能力的0.1%；然而，库容的减少并不能抵消流域整体抗洪能力的影响。根据模型预测，东Lents洪水流域的泥沙保护使约翰逊河与威拉米特河汇合处的年泥沙负荷减少了1%，从而改善了下游的水质和抗洪能力。
A study of floodplain sedimentation on a recently restored floodplain is presented. This study uses a two‐dimensional hydro‐morphodynamic model for predicting flow and suspended‐sediment dynamics in the downstream of Johnson Creek, the East Lents reach, where the bank of the river has been reconfigured to reconnect to a restored floodplain on a 0.26 km2 (26‐ha) site. The simulation scenarios include 10‐, 50‐, 100‐ and 500‐year event‐based deposition modelling of flood events and long‐term modelling using the 64 historical flood events between 1941 and 2014. Simulation results showed that the restored floodplain significantly attenuates the upstream flood peak by up to 25% at the downstream. Results also indicated that approximately 20%–30% of sediment from the upstream is deposited on the East Lents floodplain. Furthermore, deposited sediment over the simulated period (1941–2014) is approximately 0.1% of the basin's flood storage capacity; however, the reduction in the storage does not offset the overall flood resilience impact of the flood basin. The sediment conservation at the East Lents flood basin as predicted by the model reduces the annual sediment loading of the Johnson Creek by 1% at the confluence with Willamette River, providing both improved water quality and flood resilience further downstream.