SOME RESULTS OF THE GEO‐ELECTRICAL RESISTIVITY METHOD IN GROUND WATER INVESTIGATIONS IN THE NETHERLANDS*

In the year 1958 the Service for Water Management of the „Rijkswaterstaat” started its program of geo‐electrical resistivity prospecting in the western part of the Netherlands. The aim of this program was to obtain data on the salinity distribution of the ground water.

The ground water regime in this part of the Netherlands is most intricate. This is due to the geological and geo‐hydrological conditions and to the low elevation of the land. Many reclaimed areas are up to several metres below mean sea level.

The resistivity data obtained are closely related to the salinity of the ground water. On the basis of bore hole data it was even possible to arrive at calibration curves for the salinity of the ground water in sand deposits. Under special conditions it was also possible to draw conclusions with respect to the presence of less permeable formations as e.g. clay layers.

Some remarks are given on the practical performance and the interpretation of the measurements.

A review is given of the work done until now. Some results are shown by means of maps of the salinity distribution of the ground water in the western and northern parts of the Netherlands.

Two examples are described of the use of the data obtained during the survey in the province of Zuid‐Holland.

Another two examples are presented of detailed investigations for special purposes in relatively small areas.