 |
| Titel |
A statistical model derived from a physical-based model for assisting local decision makers in potential flood situations in small, flash-flood-prone mountain catchments. |
| VerfasserIn |
Jan Schwanbeck, Rolf Weingartner |
| Konferenz |
EGU General Assembly 2011
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250054332
|
|
|
|
|
|
| Zusammenfassung |
| Decision making during flood situations is particularly challenging in small,
flash-flood-prone mountain catchments with quite short times of concentration. Hydrological
models driven by weather forecasts, which have a lead time of several hours, may be
helpful in this case as time for prevention can be gained. However, the spatial and
quantitative accuracy of such a meteorological forecast, especially rainfall data,
usually decreases with increasing lead-time. In addition, rainfall-runoff models of
small catchments are highly sensitive to imprecision in areal rainfall due to the
restricted surface area. As a consequence, decisions on flood alerts should rather
be based on short-term meteorological weather forecasts, on nowcasts or even on
real-time measurements of rainfall, which is transformed into runoff by a hydrological
model. To benefit from a best possible meteorological forecast while simultaneously
retaining sufficient time for alerting and for prevention, the hydrological model should
be on one hand time efficient and on the other suitable for application by local
authorities.
To fulfil these requirements, we propose a statistical model consisting of a set of
scatter-plots relating areal precipitation to peak flow and also taking into account further
decisive parameters such as storm duration, distribution of rainfall intensity in time as well as
the catchment’s antecedent moisture conditions. A deterministic hydrological modelling
system provides the multivariate dataset needed for the statistical analyses and modelling.
After calibration and validation, the modelling system is employed to simulate repeatedly the
runoff response for a five-day period in summer with gradually altered previous moisture
conditions and systematically modified rainfall event properties, i.e. rainfall intensity and
duration. These properties cover and even exceed the range of observed values. In the
statistical model, however, the extrapolated values are explicitly stated to be less
confidential.
The final aim of this project is to provide a methodology for a decision support tool,
which enables local authorities to base their decisions on the most recent rainfall data as well
as additional information of rainfall data uncertainty. Strengths and weaknesses of the
proposed approach are discussed in a case study. The findings of this case study will lead to
further improvements of the proposed approach. |
|
|
|
|
|
|