Journal cover Journal topic
Natural Hazards and Earth System Sciences An interactive open-access journal of the European Geosciences Union
Nat. Hazards Earth Syst. Sci., 16, 1841-1853, 2016
https://doi.org/10.5194/nhess-16-1841-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
10 Aug 2016
Developments in large-scale coastal flood hazard mapping
Michalis I. Vousdoukas1,2, Evangelos Voukouvalas1, Lorenzo Mentaschi1, Francesco Dottori1, Alessio Giardino3, Dimitrios Bouziotas1,3, Alessandra Bianchi1, Peter Salamon1, and Luc Feyen1 1European Commission, Joint European Research Centre (JRC), Via Enrico Fermi 2749, 21027, Ispra, Italy
2Department of Marine Sciences, University of the Aegean, University Hill, 41100, Mitilene, Lesbos, Greece
3Deltares, P.O. Box 177, 2600 MH Delft, the Netherlands
Abstract. Coastal flooding related to marine extreme events has severe socioeconomic impacts, and even though the latter are projected to increase under the changing climate, there is a clear deficit of information and predictive capacity related to coastal flood mapping. The present contribution reports on efforts towards a new methodology for mapping coastal flood hazard at European scale, combining (i) the contribution of waves to the total water level; (ii) improved inundation modeling; and (iii) an open, physics-based framework which can be constantly upgraded, whenever new and more accurate data become available. Four inundation approaches of gradually increasing complexity and computational costs were evaluated in terms of their applicability to large-scale coastal flooding mapping: static inundation (SM); a semi-dynamic method, considering the water volume discharge over the dykes (VD); the flood intensity index approach (Iw); and the model LISFLOOD-FP (LFP). A validation test performed against observed flood extents during the Xynthia storm event showed that SM and VD can lead to an overestimation of flood extents by 232 and 209 %, while Iw and LFP showed satisfactory predictive skill. Application at pan-European scale for the present-day 100-year event confirmed that static approaches can overestimate flood extents by 56 % compared to LFP; however, Iw can deliver results of reasonable accuracy in cases when reduced computational costs are a priority. Moreover, omitting the wave contribution in the extreme total water level (TWL) can result in a  ∼  60 % underestimation of the flooded area. The present findings have implications for impact assessment studies, since combination of the estimated inundation maps with population exposure maps revealed differences in the estimated number of people affected within the 20–70 % range.

Citation: Vousdoukas, M. I., Voukouvalas, E., Mentaschi, L., Dottori, F., Giardino, A., Bouziotas, D., Bianchi, A., Salamon, P., and Feyen, L.: Developments in large-scale coastal flood hazard mapping, Nat. Hazards Earth Syst. Sci., 16, 1841-1853, https://doi.org/10.5194/nhess-16-1841-2016, 2016.
Publications Copernicus
Download
Short summary
Coastal flooding has severe socioeconomic impacts that are projected to increase under the changing climate. The present contribution reports on efforts towards a new methodology for mapping coastal flood hazard at European scale, combining the contribution of waves, improved inundation modeling and an open, physics-based framework which can be constantly upgraded whenever new and more accurate data become available.
Coastal flooding has severe socioeconomic impacts that are projected to increase under the...
Share