 |
| Titel |
The influence of spatial and temporal rainfall structure on the PMF for small alpine catchments |
| VerfasserIn |
Fraenz Zeimetz, Ramona Receanu, Jacques-André Hertig, Anton Schleiss |
| Konferenz |
EGU General Assembly 2014
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250092489
|
| Publikation (Nr.) |
 EGU/EGU2014-6840.pdf |
|
|
|
|
|
| Zusammenfassung |
| The estimation of the extreme flood, often referred to as the design flood, is an important
issue for the safety of dams and other anthropogenic structures. However, it is still related to
huge uncertainties. The design flood is considered in Switzerland as 1.5•Q1000.
Nowadays, hydrological modeling offers great possibilities for flood estimation,
starting from a known precipitation. However, most of the time this precipitation is
uniformly distributed, and the influence of its particular spatial or temporal structure is
disregarded.
This paper aims to shed light on the issue of the influence of spatial and temporal
structure of precipitation on the flood hydrograph, not only in terms of concentration time,
but also as maximum flow. From an initial spatial distribution point of view, different
distributions of the intensity clouds over the watershed are analyzed. The number and shape
of these clouds, as well as their initial position, can have a significant influence on the shape
of the resulting flood. The paper analyzes the influence of these initial conditions. In the
second part of this paper, the influence of a spatio-temporal structure is analyzed. Several
precipitation structures are built for long durations of 9, 12 and 24 hours, using as building
blocks the spatial distributions up to 6h, for which the used model has already been
tested. The goal of this development is to obtain rain structures which are both
spatially and temporally closer to these occurring naturally. As opposed to a uniform
distribution, these realistic spatio-temporal distributions can lead to variations in the
maximum discharge, out of which only the maximum value is retained as the design
flood.
The precipitation values used as inputs in the model are the PMP (Probable Maximum
Precipitation), and thus the obtained flood is the PMF (Probable Maximum Flood). Results
are presented for two Swiss alpine catchments and various spatial and temporal rain
distributions. These are compared to the uniform and triangular hyetographs, constant in
space. |
|
|
|
|
|
|