Flood risk map

Mapping services for knowledge of flood phenomena

What is it ?

These maps are built from hydrogeological studies to prevent the risk of flooding. Area mapping allows private companies and local communities to apprehend the risk of flooding. It can be used as a first-line tool before a field visit or the launch of more detailed hydraulic and hydrological studies.

It is essential in the context of the establishment of an evacuation plan but also to carry out an environmental diagnosis prior to any development of a zone of economic and ecological interest.


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Interests of flood risk map

The map is intended to assess flood-prone areas and propose technical, legal and human solutions to deal with them. To achieve this, it is essential to map the areas at risk and to regulate these areas by:




Prohibiting new human settlements in flood risk areas and governing them in other flood-prone areas





Defining constructibility rules in floodable areas prescribing measures to reduce vulnerability of facilities and constructions, do not clog water flow and preserve flood expansion areas





This map document is intended to be updated regularly due to the current context of climate change and land use.


The different types of risk maps

This is the result of the cross between the susceptibility card and the loss card. The zoning map is defined in three zones:

Red Zone



Construction is prohibited because of too much risk or because the area is dedicated to the rolling of the flood




Blue Zone



Buildings are permitted provided that certain requirements are met




White Zone



Not floodable for the reference flood, this zone is not regulated.





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