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 management ; - to indicate the extent of
human influence on groundwater quality. This report gives the results of
analysis in 1990 from 36 monitoring points in the province of