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| Titel |
Urban micro-scale flood risk estimation with parsimonious hydraulic modelling and census data |
| VerfasserIn |
C. Arrighi, M. Brugioni, F. Castelli, S. Franceschini, B. Mazzanti |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1561-8633
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| Digitales Dokument |
URL |
| Erschienen |
In: Natural Hazards and Earth System Science ; 13, no. 5 ; Nr. 13, no. 5 (2013-05-31), S.1375-1391 |
| Datensatznummer |
250018454
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| Publikation (Nr.) |
 copernicus.org/nhess-13-1375-2013.pdf |
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| Zusammenfassung |
| The adoption of 2007/60/EC Directive requires European countries to implement
flood hazard and flood risk maps by the end of 2013. Flood risk is the
product of flood hazard, vulnerability and exposure, all three to be
estimated with comparable level of accuracy. The route to flood risk
assessment is consequently much more than hydraulic modelling of inundation,
that is hazard mapping. While hazard maps have already been implemented in
many countries, quantitative damage and risk maps are still at a preliminary
level. A parsimonious quasi-2-D hydraulic model is here adopted, having many
advantages in terms of easy set-up. It is here evaluated as being accurate in
flood depth estimation in urban areas with a high-resolution and up-to-date
Digital Surface Model (DSM). The accuracy, estimated by comparison with
marble-plate records of a historic flood in the city of Florence, is
characterized in the downtown's most flooded area by a bias of a very few
centimetres and a determination coefficient of 0.73. The average risk is
found to be about 14 € m−2 yr−1, corresponding to about 8.3% of residents' income. The
spatial distribution of estimated risk highlights a complex interaction
between the flood pattern and the building characteristics. As a final
example application, the estimated risk values have been used to compare
different retrofitting measures. Proceeding through the risk estimation
steps, a new micro-scale potential damage assessment method is proposed. This
is based on the georeferenced census system as the optimal compromise between
spatial detail and open availability of socio-economic data. The results of
flood risk assessment at the census section scale resolve most of the risk
spatial variability, and they can be easily aggregated to whatever upper
scale is needed given that they are geographically defined as contiguous
polygons. Damage is calculated through stage–damage curves, starting from
census data on building type and function, for the main categories in the
study area: structures, household contents and commercial contents. This
method is tested in the area of the St. Croce district in Florence, one of the
most seriously affected in the famous 1966 flood. |
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