Grondwaterkwaliteit in stedelijk gebied en op locaties met oeverinfiltratie ; twee selecties uit het Landelijk Meetnet Grondwaterkwaliteit

The Dutch National and Provincial Groundwater Quality Network (LMG/PMG) have been designed to keep track of the shallow groundwater quality (well screens at 10 and 25 m below surface). The average monitoring site density is 1 per 100 km2. Since 1984 samples have been collected yearly and analysed for macrochemical parameters and heavy metals. Site selection criteria were mainly based on land use, soil type and the hydrological situation. The aim of this study was to describe groundwater quality and its change in the period 1984-1995 in two sets of sites from the LMG/PMG. The two sets are urban area (65 selected sites) on the one hand and river bank infiltration (34 selected sites) on the other hand. It was found that the two sets had a wide variety in groundwater compositions. Groundwater quality in urban areas is different from the nearest surrounding monitoring sites. Groundwater composition at sites with river bank infiltration is influenced by the infiltrating surface water. For both sets, changes in groundwater quality over the period 1984-1995 were small