Groundwater bodies - Guyana - State of the Places Version 2019

A body of groundwater is a separate volume of groundwater within one or more aquifers, constituting the basic delineation of aquatic environments intended to be the unit of assessment for the WFD. Groundwater bodies are derived from work done on the BDLISA repository. The water bodies are divided according to the following main principles: - Water bodies are defined on the basis of geological and hydrogeological criteria; - Redistribution of water bodies to take account of the effects of anthropogenic pressures must remain limited; - The boundaries of water bodies must be stable and sustainable; - Like bodies of surface water, the delimitation of bodies of groundwater is organised on the basis of a typology. This typology is largely inspired by the one developed for hydrogeological entities defined in the context of the BDLISA revision. It is based on the geological nature and hydrodynamic behavior or "large" operation of aquifer systems (nature, flow velocity). It comprises two levels of characteristics (main and secondary); - Water bodies may trade with each other; - All water withdrawals for drinking water supplying more than 10 m3/day or used to supply water to more than 50 persons must be included in a body of water; - Deep groundwater, unrelated to rivers and surface ecosystems, from 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; - Given its size, a body of water may have a certain spatial heterogeneity both in terms of its hydrogeological characteristics and its qualitative and quantitative status; - At any point several water bodies may overlap. (source: according to BRGM, IMPLEMENTATION OF THE WFD: IDENTIFICATION AND DELIMITATION OF SOUTHWATER MASSES - methodological guide, January 2003) WFD reporting correspondence: This entity corresponds to WISE's Ground Water Body (GWB) concept. Layers shall be disseminated in a format compliant with the SANDRE Data Dictionary of the Water Body Repository, version 1.4.地下水水体（groundwater body）是指单个或多个含水层内的独立地下水体，是《水框架指令》(Water Framework Directive, WFD) 划定的用于评估的水生环境基本单元。 地下水水体体系源自BDLISA数据库的相关研究成果。 地下水水体的划分遵循以下核心原则： - 地下水水体的划定以地质与水文地质标准为依据； - 因人为压力影响而进行的水体重划必须受到严格限制； - 地下水水体的边界需保持稳定且可持续； - 与地表水体一致，地下水水体的划定需基于分类体系。该分类体系很大程度上借鉴了BDLISA修订版中定义的水文地质实体分类方案，以含水层系统的地质属性、水动力特征或“宏观”运行特性（如介质类型、水流速度）为基础，包含两级特征划分（主特征与次特征）； - 地下水水体之间可发生水力交换； - 所有日取水量超过10立方米，或供水服务人数超过50人的饮用水取水工程，均需纳入某一地下水水体范畴； - 与河流及地表生态系统无关联、无取水活动，且因水质问题（如盐度、温度等）或技术经济原因（取水成本过高）不适宜作为饮用水水源的深层地下水，可不纳入地下水水体范畴； - 受自身规模影响，地下水水体在水文地质特征、水质与水量状态上可能存在一定空间异质性； - 在任意空间点位上，可同时存在多个重叠的地下水水体。 （资料来源：法国地质与矿业研究局（Bureau de Recherches Géologiques et Minières, BRGM），《<水框架指令>实施：南部水体的识别与划定——方法学指南》，2003年1月） WFD报告对应关系：本地下水水体实体与WISE的地下水水体（Ground Water Body, GWB）概念一致。 相关图层需按照符合法国水信息服务（Service d'Information sur les Eaux, SANDRE）水体数据库数据字典（版本1.4）的格式进行公开发布。