Under Framework programme 7 (FP7), the IMPRINTS project has started in January 2009. IMPRINTS stands for “IMproving Preparedness and RIsK maNatement for flash floods and debris flow events” and addresses issues of early and accurate warning for flashfloods and debris floods.

Within IMPRINTS, the JRC will test a flash flood early warning system based on state-of-the-art probabilistic weather forecasting input data. We make use of the Limited area Ensemble Prediction System (LEPS) provided by the Consortium for Small scale Modeling (COSMO). COSMO-LEPS ensembles are fed into LISFLOOD hydrological model, to obtain discharge estimates. Likewise, discharge climatology is created from a continuous meteorological dataset based on 30-year COSMO-LEPS hindcasts, and used as reference to detect threshold exceedance in the operational ensemble hydrographs. Coherent reference climatology is particularly useful for flash flood events, as they often take place in small watersheds, where no gauge measurements are available. The concept of persistence of meteorological forecasts is also tested as a method to improve the detection of severe events. Starting from the operational 5-km simulation at the European scale, when a signal for possible flash flooding is detected a regional catchment-scale simulation is activated on a finer spatial scale (1 km grid resolution). Two targeted analyses are carried out to investigate an automatic rule to activate the fine-scale analysis the influence of initial conditions on the estimated hydrographs, and in turn on threshold exceedances. Some of the IMPRINTS testbeds are chosen as case study, starting with the Gardon d’Anduze catchment, in France, and the Verzasca, in Switzerland. First results look promising for a future operational implementation of a flash flood early warning system at the European scale.

Feasibility study on increasing lead-time of weather driven flash-floods

This feasibility study was carried out for the FLOODS action by the Laboratoire des Transferts en Hydrologie et Environnement (LTHE) of the university Joseph Fourier in Grenoble.

The aim of the proposed study is twofold:

1. to summarise the current state of the art of flash-flood prediction, and
2. to identify possible future co-ordinated research activities on flash-floods in Europe.

The main objective is to establish in Europe a consistent strategy to improve our understanding of flashfloods under changing climate and land-use pressures and to adapt engineering methods of now-casting and long-term planning in consequence.

The study identified the following issues

There is a real necessity to maintain a strong European research focussed on the understanding of the hydrometeorological processes leading to flash-flood To assess this interdisciplinary research, complementary approaches and tools must be developed and maintained at the same time, and must be done at the European level to support the costs and the personal efforts The link between operational services, end-users and the research community must be reinforced There is a real need to centralize and capitalize works and data on a same region of interest

From all these points, long term and concerted actions must be recognized at the European level.

Download the PDF version here [1.3 Megabytes]

FLOODS action ->  FLOODSITE FP6 project

Within the framework of the FLOODSITE FP6 project, the FLOODS action of  the JRC has carried research related to flashfloods. Building on the methodologies developed for the European Flood Alert System (EFAS), a regional approach for flash flood warning also in ungauged river basins is being proposed.

The concept is based on the principle of discharge threshold exceedances as opposed to a rainfall exceedance. The flash flood from 8/9th September 2002 in the Cevennes-Vivarais region, a flash-flood prone region in France, has been studied in detail. This event is one of the most important floods ever recorded in the Cevennes–Vivarais region. It caused 24 casualties and economic damage estimated at 1.2 billion euros. Using the high-resolution operational weather forecasting data from the German weather service, the event could be forecasted more than 24 hours in advance. The methodologies were also tested for the flashflood event on 29th August 2003 in the Fella and Isonzo river basin in Italy and Slovenia, as well as the flash flood event on 24th October 2006 in Slovenia in the Goriska Region. The comparison studies confirm the potential of the approach for regional early flashflood warning.

Contact person: Jutta Thielen