Groundwater bodies — Mayotte — Premises State Version 2019

A body of groundwater is a distinct volume of groundwater within one or more aquifers, constituting the elementary separation of aquatic environments to be the WFD assessment unit. Groundwater bodies are derived from work carried out on the BDLISA benchmark. The breakdown used for water bodies follows the following main principles: — Water bodies shall be demarcated on the basis of geological and hydrogeological criteria; — The recutting of water bodies to take account of the effects of anthropogenic pressures must remain limited; — The limits of water bodies must be stable and sustainable; — In the image of surface water bodies, the delimitation of groundwater bodies is organised on the basis of a typology. This typology is largely based on the one developed for hydrogeological entities defined in the context of the BDLISA review. It is based on the geological nature and hydrodynamic behaviour or large operation of aquifer systems (nature, flow rate). It comprises 2 levels of characteristics (main and secondary); — Water bodies may have exchanges between them; — All drinking water samples supplying more than 10 m³/day or used for the supply of water to more than 50 persons must be included in a body of water; — Deep groundwater, unrelated to water courses and surface ecosystems, in which no abstraction takes place and which is unlikely to be used for drinking water because of its quality (salinity, temperature, etc.), or for technical and economic reasons (disproportionate cost of abstraction) may not constitute water bodies; — In view of its size, a body of water may have a degree of spatial heterogeneity in terms of both its hydrogeological characteristics and its qualitative and quantitative state; — At any point, more than one body of water may overlap. (source: According to BRGM, WFD IMPLEMENTATION: Identification AND DELIMITATION OF SOUTERRAINE WATERSHIP — Methodological Guide, January 2003) DCE reporting correspondence: This entity corresponds to the concept of WISE Ground Water Body (GWB). The layers are distributed in a format consistent with the picker data dictionary of the Water Benchmark Ref. version 1.4.