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| Titel |
A statistical model derived from process-based modelling to assist flood risk minimising reservoir operation in a pre-alpine flash flood prone catchment |
| VerfasserIn |
Jan Schwanbeck, Daniel Viviroli, Rolf Weingartner, Ines Röser, Jürg Trösch |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250035408
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| Zusammenfassung |
| Construction activities at the central railway station of the Swiss metropolis Zurich
temporarily enhance the risk for flooding due to reduced cross-section of River Sihl, which
drains a flash flood prone catchment with an area of 336 km2. Floods triggered in the
headwater area (155 km2) can be retained by a large reservoir (Lake Sihlsee) constructed
for hydroelectric power production. An anticipatory operation of this reservoir
based on an early flood-warning system can simultaneously reduce the flood risk
downstream of the dam and minimise the economic losses due to excessive release of
water, which cannot be used for hydropower production, prior to heavy rainfall.
Ideally, such a flood warning system includes a complex, deterministic watershed
model driven by meteorological weather forecasts. However, more straightforward
approaches for flood risk oriented reservoir control can sometimes be required owing to a
tight time schedule or limited funding available for development of appropriate
rules.
Our study discusses the development and application of a statistical model which can be
used for peak flow forecasting as well as for planning of precautionary reservoir
operation to minimise the likelihood of flooding. The statistical model is presented as
a matrix of scatter-plots relating areal precipitation of different duration to peak
flow at the catchment outlet, also considering initial water levels in the reservoir.
A combined deterministic hydrologic-hydraulic modelling system was set up to
provide the data needed for the statistical model. This system was employed to
simulate runoff response from observed rainfall events, taking into account the
different initial reservoir water levels. Furthermore, the modelling system was used
for extrapolating the range of observed rainfall-runoff events with help of rainfall
scenarios. The statistical model has proven its utility in practical application. It
supports a team of specialists in their decision on reservoir operation in case of flood
warnings. |
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