Journal cover Journal topic
Natural Hazards and Earth System Sciences An interactive open-access journal of the European Geosciences Union
https://doi.org/10.5194/nhess-2018-127
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
Research article
07 May 2018
Review status
This discussion paper is a preprint. It is a manuscript under review for the journal Natural Hazards and Earth System Sciences (NHESS).
Understanding epistemic uncertainty in large-scale coastal flood risk assessment for present and future climates
Michalis I. Vousdoukas1,3, Dimitrios Bouziotas1,2, Alessio Giardino2, Laurens M. Bouwer2, Evangelos Voukouvalas1, Lorenzo Mentaschi1, and Luc Feyen1 1European Commission, Joint European Research Centre (JRC), Via Enrico Fermi 2749, I-21027-Ispra, Italy
2Deltares, P.O. Box 177, 2600 MH Delft, the Netherlands
3Department of Marine Sciences, University of the Aegean, University hill, 41100, Mitilene, Lesbos, Greece
Abstract. An upscaling of flood risk assessment frameworks beyond regional and national scales has taken place during recent years, with a number of large-scale models emerging as tools for hotspot identification, support for international policy-making and harmonization of climate change adaptation strategies. There is, however, limited insight on the scaling effects and structural limitations of flood risk models and, therefore, the underlying uncertainty. In light of this, we examine key sources of epistemic uncertainty in the Coastal Flood Risk (CFR) modelling chain: (i) the inclusion and interaction of different hydraulic components leading to extreme sea-level (ESL); (ii) inundation modelling; (iii) the underlying uncertainty in the Digital Elevation Model (DEM); (iv) flood defence information; (v) the assumptions behind the use of depth-damage functions that express vulnerability; and (vi) different climate change projections. The impact of these uncertainties to estimated Expected Annual Damage (EAD) for present and future climates is evaluated in a dual case study in Faro, Portugal and in the Iberian Peninsula. The ranking of the uncertainty factors varies among the different case studies, baseline CFR estimates, as well as their absolute/relative changes. We find that uncertainty from ESL contributions, and in particular the way waves are treated, can be higher than the uncertainty of the two greenhouse gas emission projections and six climate models that are used. Of comparable importance is the quality of information on coastal protection levels and DEM information. In the absence of large-extent datasets with sufficient resolution and accuracy the latter two factors are the main bottlenecks in terms of large-scale CFR assessment quality.
Citation: Vousdoukas, M. I., Bouziotas, D., Giardino, A., Bouwer, L. M., Voukouvalas, E., Mentaschi, L., and Feyen, L.: Understanding epistemic uncertainty in large-scale coastal flood risk assessment for present and future climates, Nat. Hazards Earth Syst. Sci. Discuss., https://doi.org/10.5194/nhess-2018-127, in review, 2018.
Michalis I. Vousdoukas et al.
Michalis I. Vousdoukas et al.
Michalis I. Vousdoukas et al.

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