English Abstract The Dutch groundwater quality monitoring network
includes 390 monitoring points. The frequency of sampling is once a year.
The objectives of the network are: - to make an inventory of the present
quality in relation to soil use, type of soil and hydrogeological
conditions; - to distinguish long term changes in quality; - to provide
data for quality control and groundwater control; - to indicate the extent
of human influence on groundwater quality. This report gives the results of
analysis in 1991 from 20 monitoring points in the province of