Monitoring stations (Nitrates Directive) shallow filters (WMS)

The Landelijk Measuringnet Groundwater Quality (LMG) was built between 1979 and 1984 and consists of approximately 350 measuring locations spread throughout the Netherlands. Sampling shall be carried out in permanent wells specially constructed for monitoring purposes. These observation pits were constructed just outside the fields in order to be easy to sample and not to interfere with work in the field. The sites have been selected on the basis of land type, land use and hydrological condition. Groundwater samples shall be taken at each site at depths of 5-15 m (shallow filters) and 15-30 m below the ground (deep filters). On sandy soil samples are taken from shallow observation pits each year, while samples are taken from shallow wells on the other soils (clay and peat) every two years. From deep wells a sample is taken every four years, as well as from shallow filters at measuring points with marine influences. The wells that are not sampled every year shall be interpolated for the years absent.