Generation of a consistent data base to calculate heavy rain events for mapping risk by heavy rain event induced flash floods in the state of Baden-Württemberg

Extreme rainfall events frequently cause massive damage on local scale in the state of Baden-Württemberg. With ongoing climate change an increase of occurrence of such events is to suspect. Heavy rainfall events are characterized by small spatial extent and very short time for forecast and warning. Flash floods, caused by such events are not limited to rivers but can appear everywhere. The maps of flood hazard (Hochwassergerfahrenkarten) that are developed for the state of Baden-Württemberg do not cover the hazards of such flash floods. Therefore there is not yet a concept to evaluate the risk by such events for the area of Baden-Württemberg. At the chair of Hydrology in Freiburg the model RoGeR (Runoff Generation Research) was developed, what is able to quantify the runoff generation processes for the whole state of Baden-Württemberg in a spatial resolution up to 1*1m² for every given rainfall event and antecedent moisture condition. To do this the model uses spatial information, covering the whole area of Baden-Württemberg as digital elevation model, soil properties, degree of sealing of earth surface, land cover and hydro geology. The model RoGeR is applied within this project on the whole state of Baden-Württemberg at a resolution of 5*5m² to determine the runoff coefficients for given precipitation and antecedent moisture conditions. This leads to a data base for estimation of the risk by flash floods in consequence of heavy rain events. In a first project phase the model is applied for extreme precipitation amounts and duration of one hour at return periods of 50, 100 and 1000 years. The antecedent moisture is set to wet conditions (90 % field capacity). In the second project phase the empirical frequency of occurrence of antecedent moisture conditions is considered. For each combination of antecedent moisture and precipitation characteristic (duration and amount) a combined occurrence frequency can be calculated for every 5*5m² cell of Baden-Württemberg. For each of these combinations RoGeR is applied to estimate the runoff height for the given spatial conditions (soil, land cover …). With the combined frequency of occurrence of soil moisture and precipitation a return period can be assigned to every runoff response. This leads to a set of runoff heights for a given return period and a set of return periods for a given runoff height for every 5*5m² cell in Baden-Württemberg. With these data it is possible to estimate the maximum runoff for a given return period or the shortest return period of a given runoff height as a base for risk assessment and management.

contact person: Steinbrich A
Phone: +49(0)761 203 3539
Email: andreas.steinbrich@hydrology.uni-freiburg.de

Start of project: 2015
End of project: 2016

Albert-Ludwigs-University Freiburg
Weiler M
Professur für Hydrologie

Friedrichstrasse 39
79098 Freiburg i. Br.
Germany

Phone: +49(0)761-203-3530
Fax: +49(0)761-203-3994
Email: hydrology@hydrology.uni-freiburg.de
http://www.hydro.uni-freiburg.de
Actual Research Report

• Steinbrich A
• Hoffmann A
• Stölzle M

• LUBW Karlsruhe, Land

Abflussbildungsprozesse / wild abfließendes Wasser / Starkniederschläge / Niederschlag-Abfluss-Modell / Vorfeuchte / kombinierte Wahrscheinlichkeit / Jährlichkeit / Gefährdungspotential