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| Titel |
Delineation of Flood Prone Areas using Digital Elevation Models: Scale Dependence |
| VerfasserIn |
M. Di Leo, S. Manfreda, A. Sole, M. Fiorentino |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250028112
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| Zusammenfassung |
| The delineation of the areas subject to flood inundations raises complex problems regarding
the definition of hydrological forcing and the parametrization of models for flood wave
propagation (e.g., Horritt & Bates, 2000, 2002). The increasing availability of new
technologies for the measurement of surface elevation (eg GPS, SAR interferometry, radar
and laser altimetry) led to an increase in the attraction of DEM-based procedures
for the delineation of floodplains. In recent years, much effort has gone into the
identification of flood prone areas through the use of hydrological and hydraulic studies
carried out by River Basin Authorities (public institutions dedicated to river basins
management). These studies are generally based on topographic surveys and numerical
modelling for the flood wave propagation providing an enormous database rarely
used for post processing. Manfreda et al. (2006) have recently used the technical
documentation, produced during the definition of Hydrogeological Management Plan by the
River Basin Authorities, to define a synthetic procedure for the delineation of flood
inundation exposure. The relevance of such techniques lies in the ability to characterize,
at least at first approximation, portions of the territory where is not possible to
run expensive hydrological-hydraulic simulations. The development of simplified
methodologies is taken further in the present study to investigate the relationship
between areas exposed to flood inundation and the geomorphologic characteristics of
the terrain (contributing area, local slope of the surface, curvature, TOPMODEL
topographic index) showing a strong correlation with the TOPMODEL topographic index.
Manfreda et al. (2006) also defined a new expression of the topographical index more
suited to the task of delineating flood exposure directly from a DEM analysis. This
permitted the definition of a fast procedure for the calculation of flood inundation
areas using a threshold level (ITms) to discriminate between areas exposed to flood
inundation and non exposed areas. The objective of the study is to estimate the optimal
threshold level for the identification of flood prone areas and the scale dependence of
the methodology. This approach was applied over several Italian catchments and
sub-catchments of different sizes and using DEMs at resolution changing from 2m up to
230m. |
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