Inventory of wetlands throughout the territory of the Community of Communes du Grand Couronné and on the Ban of Lay-Saint-Christophe

According to L.211-1 of the Environmental Code, I. — 1° [...] Wetland means land, whether or not operated, usually flooded or engrown with fresh water, salted or brackish on a permanent or temporary basis; vegetation, where it exists, is dominated by hygrophilic plants for at least part of the year; [...] Article R.211-108 of the same code states: • the criteria to be used relate to soil morphology linked to the prolonged presence of original water natural and possible presence of hygrophilic plants, • in the absence of hygrophilic vegetation, soil morphology is sufficient to define a wetland, • the delimitation of wetlands is carried out using flood or groundwater levels, or tidal frequencies and amplitudes. Field diagnostics refer to areas with hydrological criteria (flooding or frequent waterlogging) and/or soil (soil showing a water-saturated environment) and/or botanical (vegetation dominated by hygrophilic plants) of wetlands. They always use field surveys to justify the verification of these criteria. These areas are more specific than wetlands, but are not always exhaustive. Indeed, depending on the methodology used (flora and/or pedology), some wetlands may not be identified. When actual wetlands are demarcated according to the definition of the Environmental Code and on the basis of the criteria detailed in the Order of 24 June 2008 as amended on 1 October 2009, then it is referred to as regulatory delimitation or “water policy” wetlands. These areas are defined if the soil and flora criteria are verified, except where the vegetation present is not “spontaneous”. In this case, the soil criterion alone is sufficient to determine the wetland (see Technical Note of 26 June 2017 on the characterisation of wetlands — in particular for the definition of “spontaneous” vegetation). In the case of a project, it is up to the petitioner to prove that his project is not wetland or, if not, to delimit them by regulation. Maps of predominantly wetlands available on the project’s right-of-way are not sufficient to prove the absence of wetlands.