Elementary Groundwater Body Polygons — Guyana — Version State of the Places 2019

A body of groundwater is a separate 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 repository. The cut-off for water bodies follows the following key principles: — Water bodies are demarcated on the basis of geological and hydrogeological criteria; — The redistribution 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; — Like bodies of surface water, the delimitation of groundwater bodies is organised on the basis of a typology. This typology is largely based on that developed for hydrogeological entities defined in the context of the revision of BDLISA. It is based on the geological nature and hydrodynamic behaviour or “big” functioning of aquifer systems (nature, flow rate). It has 2 levels of characteristics (main and secondary); — Water bodies may have exchanges between them; — All water for drinking water supplying more than 10 m³/day or used for the supply of water for more than 50 persons must be included in a body of water; — Deep groundwater, unrelated to rivers and surface ecosystems, from which no sampling takes place and which is not likely to be used for drinking water because of its quality (salinity, temperature, etc.), or for technical and economic reasons (cost of disproportionate abstraction) may not constitute bodies of water; — Given its size, a body of water may have a certain spatial heterogeneity in terms of both its hydrogeological characteristics and its qualitative and quantitative status; — At any point several bodies of water can be superimposed. (source: according to BRGM, WFD IMPLEMENTATION: Identification AND DELIMITATION OF SOUTERRAINE WATER MASSES — methodological guide, January 2003) The layers are distributed in a format consistent with the SANDRE Data Dictionary of the Water Body Reference, version 1.4.