Mapping of Channel Watercourses — Normandy

Under water policy, streams are media characterised by flows not exclusively fed by local rain events. The case law recognises three cumulative criteria for their identification: a sufficient flow rate for most of the year, feeding from a source and the existence of a natural bed originally. The identification of some small streams may, however, remain delicate. If there is any doubt about at least one of these criteria, the others being confirmed, the additional analysis is based on the presence of banks, a bed with a specific substrate, aquatic life and upstream-down flow continuity. A second field expertise in a different hydrological season may be necessary. http://www.manche.gouv.fr/Politiques-publiques/Environnement-risques-naturels-et-technologiques/Eau-et-milieux-aquatiques/Cartographie-des-cours-d-eau