Trends identification in groundwater for the Water Framework Directive and the Groundwater Directive
Voorstellen II voor trendbepaling in grondwater voor de KRW en de GWR
26 June 2012, PDF |
22 pages |
Verweij W, Meijles JG, Reijnders HFR
RIVM Report 607402008
The European Water Framework Directive (WFD) and Groundwater Directive (GRW) states that concentrations of pollutants in groundwater must not increase. In practice it proved difficult to establish such an increase. In two previously published reports, the RIVM, commissioned by the Ministry of Infrastructure and Environment (IenM), practical advice has been given for specifying the technical guidelines from the EU. Premise is that existing information has to be used to determine trend. In the underlying report answers are given by the County Councils and RIVM for issues that were not solved. Ultimately, a protocol will be formulated to establish trends in the concentration of substances and in doing so the groundwater quality.
Examples of remaining issues are: what to do with a lack of information or incomplete time series, of which the concentration of a substance over time is measured at one observation point. In such cases, the trend can be established on the basis of an 'expert judgement'. An expert judgement is not based upon calculations with data but the experts evaluate the groundwater quality on the basis of qualitative assessment of the available data. For this the County Councils and RIVM have developed a protocol. Technically, the age of groundwater does not need to be determined but it can be used to improve the grasp of trends in the ground water system.