The model GeoTOP provides a detailed three-dimensional view of the subsurface in the Netherlands until a maximum depth of 50 metres below NAP (Dutch Ordnance Level). GeoTOP schematises onshore Netherlands in millions of voxels (cells), each measuring 100 by 100 metres horizontally and 50 centimetres vertically. Each voxel in the model contains information on the lithostratigraphy and lithological classes, including the probability of occurrence for each lithological class. GeoTOP refines the top of the DGM and of the REGIS II model, providing a sound framework for subsurface-related questions on groundwater management, natural resources and infrastructure.
GeoTOP models individual regions that roughly correspond to provinces. In the last DINO version, regions Zeeland, Zuid-Holland, Noord-Holland, Rijn–Maas gebied (the Rhine–Meuse area), West Wad (Friesland and the western part of the Wadden Sea) and Oost Wad (Groningen and the eastern part of the Wadden Sea) are available.
GeoTOP does not include the subsurface under the Dutch part of the North Sea.
More detailed information about the development of the model is described in the report Totstandkomingsrapport GeoTOP (PDF in dutch - 9.9MB) regarding the regions West Wad and Oost Wad and in the Totstandskomingsrapport GeoTOP - met nieuwe methodiek lagenmodellering (PDF in dutch - 8.9MB) regarding the regions Noord-Brabant and Noord- and Midden-Limburg.
GeoTOP has been constructed per region from the available digital borehole logs stored in the DINO database, which contains some 430,000 borehole logs. For the regions Zeeland and Zuid-Holland about 23,000 and 50,000 logs respectively have been used. For the region Rhine–Meuse area, additional borehole logs from Utrecht University’s Department of Physical Geography have been used. The borehole data have been supplemented with data from cone-penetration tests and from digitised geological maps.
Application and reliability of the model output
The GeoTOP model provides information on the stratigraphy, lithology and the interrelated physical and chemical properties of the subsurface of onshore Netherlands to a depth of 50 metres below NAP. The model contains as much available data and information on the subsurface as possible, summarised in borehole logs with lithostratigraphic interpretations, a layer model and a voxel model, all of which can be requested via DINOloket.
GeoTOP models the subsurface at a subregional scale that is suitable for applications at the levels of province, municipality and district. This scale is comparable to the 1:50,000 scale used for one of its predecessors, the Geological Map of the Netherlands. If a larger scale is required (when working at the level of streets or individual buildings), GeoTOP can serve as a framework to which more detail can be added.
GeoTOP is broadly applicable for issues in which the stratigraphy and lithology of the shallow subsurface are important, such as groundwater studies, the prediction of land subsidence, insight into the depth required for foundations, the location of sandy channels and the calculation of volumes of natural resources.
More details about the quality of the model can be found in the document"Kwaliteitstoetsingsdocumenten GeoTOP" (ZIP in Dutch - 2.7MB).
Current and earlier versions
A list with reports on this model is available on the Report back page.
3D representation of the GeoTOP model