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Flood risk: using memories to create management policies of the future

Flooding in Soultzmatt in 1896. Anonymous. Collection of Brice Martin (UHA)


By studying past floods along with current preventive and protective measures and policies, can we anticipate risk better? Based on this premise, the French-German research project TransRisk2 analyzes cross-border management and representations of flood risk in the Rhine river basin: an innovative historical and progressive approach for this vulnerable area.

Like a radioactive cloud, water does not stop at borders, and affects both sides. Flood risk management, however, is different: every country has its own strategies and policies. What solutions can we offer? A research project [1] that looks into this issue of cross-border management of flood risk, focusing on the particularly vulnerable Rhine river basin (France/Germany/Switzerland). The aim is to understand the past to anticipate the future better and thus implement joint risk management policies.

Gathering data and memories of risk

The TransRisk2 project continues the work it began over the course of a previous project [2], which led to the creation of a historical database tracking historical cross-border floods. Geographers, historians, economists, linguists, anthropologists and mathematicians have teamed up for this historical analysis of interdisciplinary cross-border flood risk. "The idea was to establish a chronology comparing floods in the Upper Rhine in France and Germany," explains Carine Heitz, geographer at Irstea.

The database inventories over 3,000 events taking place between 1700 and the present-day, using departmental archives, newspaper articles, written documents (mayors, public figures), photographs, and even engravings. "It's proof that even back then, people wanted to record this type of event with images," says Heitz. The characteristics (water levels, frequency), causes (weather phenomena, anthropization) and the consequences (damage to the environment and infrastructure) of the events were all recorded.

Representation of the 1947 flood in Thann © Holleville N., 2015

Now that the database exists, what are we going to do with it? The initial phase of the TransRisk2 project involved work to improve the data by incorporating changes in land use (growing urban areas, changes in soil impermeability, changes in farmland) and changes in water courses and their development over time with the aim of estimating their possible impact on flood frequency. The information was then put back into context against the tension-filled backdrop of climate change. "Has climate change finally had an impact, or is this closely linked to anthropogenic changes, such as developments on embankments or the urbanization of buffer areas?" asks Heitz. The role of regional planning policies and of management of vulnerable spaces within risk management thus becomes clear.

Canal des Neufs Moulins (Colmar). Levels of historic floods of the Thur © Brice Martin (UHA)Another project looking at the way in which the database itself operates was also started. Initially designed for the scientific community or government partners, the database is now being redesigned to be interactive. The data is being made available to the general public in a move based on the theory that individuals must surely have raw information or documents (old photographs, postcards) that can populate the database. These contributions from the general public are also necessary because of the destruction of various archives by the successive wars that have impacted the region. People are stakeholders of history.

Which risk culture?

The database must encourage sharing knowledge and experience with the aim of building a collectively shared risk culture. Heitz explains: "Risk culture is the way in which individuals understand and represent risk. It is also how the memory of risk can affect or influence the way in which individuals will or will not protect themselves when faced with a current and known risk that recurs frequently." This culture is is often closely linked to information and communication between the general public and elected officials or management services.

Rambervilliers, flooding of the Mortagne 10/3/2006 © Brice Martin (UHA)Irstea is working specifically on its representations of risk and its relationship to regions. "For example, will installing a protective facility (a dam) change the way in which risk is perceived in a given area?" asks Heitz. Will inhabitants feel more protected? Will they go as far as to deny the risk? "In fact, we are looking at how vulnerability changes following the implementation of protective facilities. For example, will it increase tenfold as more risks are taken, by allowing businesses to move into these vulnerable areas?" asks Heitz. To achieve this, geographer Carine Heitz and economists Anne Rozan and Daly Bchir are working together.

Knowledge of potential risks can also have an impact on the appropriation or abandonment of an area: "Strong memories can be linked to an area previously affected by floods that, even now, push the population away from the area," clarifies Heitz. It therefore becomes necessary to acclimatize the population. Surveys of the general public and local stakeholders make it possible to analyze these developments in the representations of risk, reflecting the prevention and protection policies in place. "For example, as part of this 'Risk Culture' project, we have developed strong partnerships with the Haut-Rhin and Bas-Rhin General Councils, who are particularly keen to gain insight into how the general public perceives risk, as well as how this fear is dealt with in Germany," explains Heitz.

This is good news, particularly as the project fits in perfectly with the implementation in France of collectively developed planning documents known as PAPI (Flood Prevention Action Programs). "It is an opportunity to be able to participate in the creation of these plans and to see how these new river basin management policies are perceived as well as their impact (positive or negative) on the way in which the area is protected as a result. The idea is to make the most of existing regulatory tools," describes Heitz.

The explicit aim of this project "without borders" is clear: to create common policies. How? By reinforcing collective memories of risk as well as by highlighting modern improvements in prevention and protection in both France and in Germany, in order to improve risk management in the future.

For more information

[1] ANR Franco-German TransRisk2 Project (2014-2017): transnational management of flood risk in the Rhine river basin. Partners include the Territorial Management of Water and the Environment (GESTE) joint research unit, under the purview of ENGEES and Irstea. For more information

[2] ANR Franco-German TransRisk1 Project (2007-2011).