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Lookup NU author(s): Dr Fergus McClean,
Professor Richard Dawson,
Professor Chris Kilsby
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
As urban populations grow, it is increasingly important to accurately characterize flood risk in cities and built up areas. Global digital elevation models (GDEMs) have recently enabled flood risk analysis at broad scale and worldwide, but their accuracy and its impact on modeled flood risk in cities has not been fully investigated. We compare flood extents, hydrographs, depths, and impacts between hydrodynamic simulations, using five spaceborne GDEM products and an airborne LIDAR product. Benchmark observations of a historical flood event in Carlisle (UK) were used to assess the accuracy of each simulation. GDEM simulations are shown to perform significantly less accurately than the airborne LIDAR‐based simulations. No DEM outperforms the others across all metrics; the MERIT DEM is the best predictor of flood extent, but TanDEM‐X performs best for discharge. However, the impacts of flooding from GDEM simulations are consistently overestimated, 2 to 3 times higher than those from LIDAR simulations. Until a high resolution, accurate, global DEM is available, multiple products should be used concurrently to enable the full uncertainty range to be quantified and communicated, to ensure flood risk management decisions are not misinformed.
Author(s): McClean F, Dawson RJ, Kilsby CG
Publication type: Article
Publication status: Published
Journal: Water Resources Research
Print publication date: 01/10/2020
Online publication date: 23/09/2020
Acceptance date: 06/09/2020
Date deposited: 21/10/2020
ISSN (print): 0043-1397
ISSN (electronic): 1944-7973
Publisher: Wiley-Blackwell Publishing, Inc.
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