What do we know about flooding and high water?

While it may be difficult to stop floods from happening, it is possible to prepare for them. Knowledge of high water events and floods is a logical place to start in managing the risk.

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Data series

Irstea's scientists have developed an in-depth understanding of flooding and high water. From collecting field data using measurement station networks to setting up a database, they are working to understand the behavior and trajectory of these events, using simulations and models in order to implement risk quantification methods.

Hydrological observatory database

Since November 2013, Irstea researchers and partners have free access to the hydrological database of 8 institute observatories in operation.

 

Historical flood database

The knowledge used to create the inventory of noteworthy floods (see below) was also used to create a Historical Flood Database (BDHI), commissioned by the Ministry of Ecology. The aim was to improve our understanding of flood risks and contribute to implementing the European Flood Directive. All documentary sources describing floods (hydrometeorological aspects and consequences), past and future, were therefore collected to create a national flood reference document.

The BDHI has been available to the public since March 2014.

 

A 200-year overview of significant floods in France

A unique inventory coordinated by Irstea because there will always be something to learn from past events.

 

A revealing dive into two centuries worth of flooding

Given the regular occurrence of flooding, the largest natural hazard in France, it seems obvious that we need to learn from past events. Read the article by Michel Lang, hydrology research engineer at Irstea, on The Conversation website.

 

Flash floods, extreme high water

From knowing about the events to understanding the risks, Irstea researchers are becoming more specialized.

Improving our understanding of flash floods

Intense, fast and difficult to predict, flash floods are one of the most destructive natural hazards in the Mediterranean region.

 

How can we evaluate extreme flood levels?

A research project is reevaluating methods of estimating extreme and/or rare floods.

 

Specific equipment

Irstea's expertise is also based on developing innovative tools and processes in laboratories and in the field.

Hydraulic facilities: floods in the laboratory!

The hydraulics hall is an exceptional extreme flood simulation facility.

 

The Yzeron river basin: a unique experimental site

Does urbanization have an impact on the hydrological regime of rivers and specifically on the risk of floods or low water levels?

 

Rain generators: simulating rain to estimate high water

No, researchers are not creating rain in their laboratories! They are using software to simulate rainfall to provide better estimates of the consequences. How does it work? The system uses statistical data gathered during observed rainfall and will eventually include projected rainfall data in order to provide long-term rainfall data. Using 30 years of data, it is possible to create 1000 years of rain or more, revealing rare events and sequences (that are nevertheless compatible with the data)! The data is then input into a hydrological model that transforms rainfall into flow, giving an idea of the amount of water that could potentially flow into a river. Although the system is based on statistics and predictions, with uncertainty never far away, it is at least possible for it to be partially quantified.

Irstea has developed two rain generators: Shypre in Aix-en-Provence and SAMPO in Lyon-Villeurbanne. Shypre specializes in heavier rainfall. SAMPO includes all types of rainfall and provides an overview of the spatial variability of events in order to model the reaction of complex river basins to various types of rain (land use, challenges, possible flood areas, potential damages). In other words, it finds problem areas. This type of expertise is in demand with insurers and reinsurers who must, for example, in accordance with European directives, carry out their own assessments on the natural hazards they are insuring.

ContactsPhilippe CantetPatrick Arnaud and Catherine Fouchier (Aix-en-Provence) / Etienne Leblois (Lyon-Villeurbanne)

Diagram (click to enlarge image)

The Shypre tool can be used as a regional tool (Shyreg) to ensure regionally appropriate statistical estimates. © Irstea