Atlas of flood zones in Brittany

The constitution of AZI s' is part of the law of 22 July 1987 which specifies that citizens have a right to #x27; information on the major risks to which they are subject. In Brittany, the DDTM des Cotes d'Armor has embarked on a multi-year programme of development of flood zones on the main water courses of the department. The DREAL Bretagne has done the same, on the other three Breton departments. On the basis of the lessons of the greatest past and known flooding and of a morphological analysis of valley bottoms, the atlases of flood zones carried out in Brittany map the maximum right-of-way of flood areas. Flood zone maps are made on a scale of 1/25000. The online layer represents this maximum grip on the departments of Finistère, d'Ille-et-Vilaine and Morbihan. L'analysis carried out on the department of Cotes d'Armor allows to go further by determining levels of: — low level: height d'water less than 0.5 m — average level: height d'water between 0.5 m and 1.0 m — strong level: height d'water greater than 1.0 m. It should be noted that some sections of water courses, in the department boundary with the Cotes d'Armor, are covered by both studies. The atlases having been made by river, the tables of each atlas were merged into a single layer all over Brittany. __Origin__ For the study under control of DREAL (departments 29, 35 and 56), the mapping of flood zones is based on: — a general analysis of the valley: geology, land use, hydraulic structures; — a phase of survey of bodies and residents who may have information on floods; — a search for archives on past floods in the State and departmental archives; — hydrogeomorphological analysis of the valley (stereoscopic analysis of aerial photographs, field reconnaissance). For the study under control of DDTM22, contact the department for more information ([email protected]). __Partner organisations__ DREAL Bretagne [See this page on geo.data.gouv.fr](https://geo.data.gouv.fr/fr/datasets/28895712cd6776bfd03b681f0b43431acaf264d1)