Developments in large-scale coastal flood hazard mapping
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 e...
Main Authors: | , , , , , , , , |
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Format: | Article |
Language: | English |
Published: |
Copernicus Publications
2016-08-01
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Series: | Natural Hazards and Earth System Sciences |
Online Access: | http://www.nat-hazards-earth-syst-sci.net/16/1841/2016/nhess-16-1841-2016.pdf |
Summary: | 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. |
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ISSN: | 1561-8633 1684-9981 |