Salinisation map 2014/2017 conservative (m-mv)

The map, based on the 2014 and 2017 helicopter measurements, shows a conservative estimate of the depth of the interface between fresh and brackish groundwater in meters relative to ground level. Taking into account the uncertainty on the measurements, two versions of the salinisation map were drawn up: 1. A conservative estimate of the depth of the boundary is based on a 95 % probability of finding fresh groundwater above this boundary. 2. An optimistic estimate of the depth of the boundary, assuming a 89 % chance of finding fresh groundwater above this boundary. Fresh water means conductivity less than 2000 µS/cm. It is appropriate to consult both interfaces to make an estimate of the fresh-breaking water distribution at a given location. In addition, the data points are available (‘salination map_2014/2017_helikopter measurements’) so that it can be verified where effectively measured and interpolated. The data points are located on flight lines where a vertical profile can be consulted with the display of salinity, bulk resistance, lithology and stratigraphy. On the profiles the boundary between fresh and brackish (optimistic and conservative) and between brackish and salt groundwater is visible. The boundary between brackish and salt groundwater is defined as 25000 µS/cm. Due to construction and other obstacles, certain areas within the coastal and polder areas could not be measured. For these areas one can fall back on the salinisation map from 1974.