Abstract

Currently, the quality of the upper metre of the groundwater is monitored on farms within the Netherlands National Monitoring Programme for Effectiveness of the Minerals Policy (LMM). The data are used both for trend analysis and for checking whether the effect of Dutch agricultural practice on water quality does not lead to the environmental quality objectives for water being exceeded. The questions raised on the use of these data for compliance checking (especially for the infiltration areas in the Netherlands, i.e. sandy regions) by the Dutch Parliament led to a study. The aim was to determine the merits and demerits of using the upper five metres of groundwater as the compliance checking level in the sandy regions. In a part of this study the focus was on the feasibility of methods to be used in a monitoring network for sampling groundwater up to five metres below groundwater level. Suitable methods twelve drilling and sampling methods for monitoring the upper five metres of groundwater in agricultural fields were surveyed and the most favourable methods selected. The most preferred proved to be one manually-driven method and one machine-driven method, both of which could bring temporary sampling filters into place. Another machine-driven method would allow placement of permanent filters. These methods still have to be tested for their applicability in the next phase of the study.