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| Titel |
Assessing the impact of uncertainty on flood risk estimates with reliability analysis using 1-D and 2-D hydraulic models |
| VerfasserIn |
L. Altarejos-García, M. L. Martínez-Chenoll, I. Escuder-Bueno, A. Serrano-Lombillo |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1027-5606
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| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 16, no. 7 ; Nr. 16, no. 7 (2012-07-05), S.1895-1914 |
| Datensatznummer |
250013356
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| Publikation (Nr.) |
 copernicus.org/hess-16-1895-2012.pdf |
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| Zusammenfassung |
| This paper addresses the use of reliability techniques such as Rosenblueth's
Point-Estimate Method (PEM) as a practical alternative to more precise Monte
Carlo approaches to get estimates of the mean and variance of uncertain
flood parameters water depth and velocity. These parameters define the flood
severity, which is a concept used for decision-making in the context of
flood risk assessment. The method proposed is particularly useful when the
degree of complexity of the hydraulic models makes Monte Carlo inapplicable
in terms of computing time, but when a measure of the variability of these
parameters is still needed. The capacity of PEM, which is a special case of
numerical quadrature based on orthogonal polynomials, to evaluate the first
two moments of performance functions such as the water depth and velocity is
demonstrated in the case of a single river reach using a 1-D HEC-RAS model.
It is shown that in some cases, using a simple variable transformation,
statistical distributions of both water depth and velocity approximate the
lognormal. As this distribution is fully defined by its mean and variance,
PEM can be used to define the full probability distribution function of
these flood parameters and so allowing for probability estimations of flood
severity. Then, an application of the method to the same river reach using a
2-D Shallow Water Equations (SWE) model is performed. Flood maps of mean and
standard deviation of water depth and velocity are obtained, and uncertainty
in the extension of flooded areas with different severity levels is
assessed. It is recognized, though, that whenever application of Monte Carlo
method is practically feasible, it is a preferred approach. |
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