文章基本信息

标题：Assessing Nature-Based and Cassical Engineering Solutions for Flood-Risk Reduction in Urban Streams
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作者：Olga Ourloglou ; Konstantinos Stefanidis ; Elias Dimitriou 等
期刊名称：Inżynieria Ekologiczna
印刷版ISSN：2081-139X
电子版ISSN：2392-0629
出版年度：2020
卷号：21
期号：2
页码：46-56
DOI：10.12911/22998993/116349
出版社：Polish Society of Ecological Engineering (PTIE)
摘要：Urbanization of stream ecosystems with the purpose of managing flash-flood events is considered nowadays responsible for habitat loss and alteration of the natural flow regime with severe implications for the ecosystem functioning.Not surprisingly river scientists have started seeking alternative options inspired from nature for mitigating flood-risk and maintaining the stream at its natural state.With this article we demonstrate the effects of a nature-based solution (NBS) for managing an urban stream based on the use of bioengineering materials (e.g.plants) and the implementation of actions that restore the stream to its natural form (e.g channel widening).We employed the HEC-RAS software to simulate flow and hydraulic components of an approximately 800m long reach of an urban stream under three different scenarios of flood risk management with a design flow set to 400m3/s.The first scenario was based on the current situation of the stream, the second scenario concerned the stream restoration by following nature-based solutions while the third scenario was based on the classical “grey” engineering approach of concrete channelization.In order to develop a detailed 3D model of the studied reach that accurately captured the current geomorphology we used Unmanned Aerial Vehicle (UAV) photogrammetry methods and the software Pix4Dmapper.Our results showed that with concrete channelization the average and maximum flow of the stream increases significantly in relation to the current situation, from 2.48 and 4.88m/s to 9.82 and 11.22 m/s respectively while the average Froude number raises from 0.36 to 1.69 implying super-critical flows.In contrast the NBS scenario retained lower flow velocities and average Froude number similar to those under the current conditions.In addition, a cost estimation analysis for both stream management techniques revealed that the NBS costs much cheaper than the traditional channelization (1,1 mil € vs 5,6 mil €).In conclusion, our findings suggest that future restoration of urban streams should consider nature-based solutions since i) they can be effective with regard to the reduction of flood-risk, ii) are cheaper than traditional “grey” techniques and iii) most importantly maintain the natural state of the ecosystem which improves not only the ecosystem functioning but also the aesthetic value within the urban context.
关键词：urban streams; stream restoration; bioengineering; nature-based solutions; hydraulic modelling; UAVs