Guidance on groundwater status and trend assessment
Guidance document. No 18
This guidance has been drafted in response to a mandate from the CIS Working Group on Groundwater (WG C). This mandate required the development of practical guidance and technical specifications for the derivation of threshold values, the assessment of status (both quantitative and chemical) and the assessment of groundwater trends and trend reversal. This guidance builds on, and complements existing WFD guidance. Its primary focus is on delivering a number of the groundwater requirements of the water framework directive (WFD) and the new groundwater directive (GWD). These include the... obligations set out in Annex V of the WFD and Articles 3, 4 and 5 and Annex II, III and IV of the GWD. The GWD establishes a requirement for Member States to derive threshold values for pollutants (or groups of pollutants) that are related to the pressures identified as putting groundwater bodies at risk. These threshold values and standards are then to be used to assess groundwater chemical status, as defined in the WFD. In addition to assessing the impacts of pollutants the WFD also requires consideration of the impacts of groundwater abstraction on groundwater bodies, dependent surface water bodies and ecosystems, and an assessment of quantitative status. The WFD and GWD also require that trends in pollutant concentrations are identified and that these trends are assessed to determine whether they are environmentally significant. Where significant upward trends exist they must be reversed through the application of programmes of measures to ensure that there are no future failures of environmental objectives. The GWD starting point for trend reversal must be defined as a proportion of the threshold value or quality standard (75% by default). This document provides practical guidance on meeting each of the requirements described above. It sets out a methodology for deriving threshold values; establishes frameworks for assessing both chemical and quantitative status; identifies a method for identifying environmentally significant trends; outlines the reporting requirements; and provides case study examples to illustrate the application of the guidance in different Member States.
- Corporate author(s): Directorate-General for Environment (European Commission) Themes: Environmental regulations, Environment policy and protection of the environment
- Subject: directive (EU), environmental impact, environmental monitoring, EU environmental policy, groundwater, water management