High-resolution simulations of extreme precipitation events for flood management

Contact: Prof. Dr. Ch. Kottmeier, Dr. G. Schädler, Dr. I. Schlüter
Project Group: IMK-TRO
Funding: BMBF

within the Joint Project
"Operational flood management for large-scale flooding events - exemplified for the middle reaches of the Elbe river " initiated by the German Ministry for Education and Research (BMBF) conducted within the BMBF research program
"Risikomanagement extremer Hochwasserereignisse (RIMAX)"

The Joint Project

Extreme precipitation events like the Elbe flooding in 2002, which largely surpass the constructive design limits imply large risks for humans and goods, for example if due to perseverative high water levels breaking of dikes and consequent flooding of inhabited areas is likely to occur. Such dangers must be recognised early by efficient prediction systems and managed by operational flood management measures.

The Elbe flooding 2002 near the village of Elster.
Photography: M. Zebisch, TU Berlin in:
Klimastatusbericht 2002 of the German Weather Service (DWD)

Managing extreme events for large river catchments poses considerable problems, including the superposition of the flood peaks of tributaries, questions of responsibility, long-term planning horizons and the formidable costs of dike building. The project presented here aims at a consistent quantification of such extreme events and at providing components which can be used routinely for flood management. This is done via the integration and the further development of existing components for the processes involved, from the synoptic situation down to the local fllod risk; the pilot region are the diked middle reaches of the Elbe river including the Mulde confluence near the city of Dessau. The components will be tested using extreme events of the past; the spatial scale will range from the precipitation in large sub-catchments of the Elbe river (see description of the subproject TP1) down to the scale of single dikes. Corresponding to the flood process chain, the project is divided into the subprojects

Precipitation and meteorology in the Elbe catchment (contribution of IMK-TRO)
Hydrology in the catchment and in the river system
Hydraulics in river sections
dike security in river sections
risk behind dikes

all of which are strongly connected.
In the following, we present some more details about the “meteorological“ subproject TP1:
Further details concerning the whole project and the other subprojects can be found here.

Subproject TP 1:

“High-resolution simulations of extreme precipitation events for flood management“

Institute for Meteorology and Climate Research at Karlsruhe University and Karlsruhe Research Centre

Aims:
During the first project phase, high-resolution (spatially and temporally) precipitation data for selected extreme flooding events will be provided, simulated with a nested version of the „Lokal-Modell“ (LM) of the German Weather Service (DWD). These data will be used by the other subprojects for discharge modelling and to study, for example, dike security and the effects of retention basins. The spatial resolution will be 1 km and 2.8 km. Using the experiences gained in this phase, a model-based analysis of the variability of the intensity of extreme events will be made. Besides providing information on the variability of extreme events, the results can serve to improve the constructive design of retention basins, dikes etc.

Precipitation amounts (mm/mon) measured during the Elbe
flooding event in August 2002.
Source: Klimastatusbericht 2002 of the
German Weather Service (DWD).

Work Packages
The subproject consists of the following work packages:
• high-resolution simulations of precipitation during selected summer and winter extreme events, validation and provision of the results for the other subprojects
• establishment of a pre-operational system for high-resolution precipitation forecasts
• development and application of a model-based method to estimate the variability of the intensity of extreme precipitation events.

Cooperations:
Institut für Wasserwirtschaft und Kulturtechnik, Universität Karlsruhe
Institut für Bodenmechanik und Felsmechanik, Universität Karlsruhe
Deutscher Wetterdienst (DWD), Offenbach
Czech Hydrometeorological Institute, Prague
Landesbetrieb für Hochwasserschutz und Wasserwirtschaft Sachsen-Anhalt
Landesamt für Umwelt und Geologie des Freistaats Sachsen
City of Dessau
stnd Consultants, Karlsruhe
Dr. Karl Kast + Partner Consultants, Ettlingen
BLM Geotest Consultants, Berlin

Information about the present state of the project can be found here.

Veröffentlichungen
Title	Image	Source	Short Description
Rekonstruktion extremer Niederschläge und Abschätzung ihrer Variabilität mit Hilfe numerischer Modelle		Fachgemeinschaft Hydrologische Wissenschaften, Forum für Hydrologie und Wasserbewirtschaftung, 15.06 (Bd. 3), 109-112 (2006)
Rekonstruktion extremer Niederschläge und Abschätzung ihrer Variabilität mit Hilfe numerischer Modelle		Tag der Hydrologie, München, 22.03.-23.03.2006 (Poster)