The Board of the Technology Foundation STW has awarded grants to five new technical-scientific projects, including a TU Delft project aimed at creating an accurate and easily verifiable reference surface for Dutch coastal waters.

Reference surface

The surface area of the the Netherlands has been accurately mapped but, surprisingly, there is no satisfactory reference surface for the Wadden Sea and the North Sea Continental Shelf. Such a reference surface indicates how high the water would be if there were no effects of wind, waves and tides. This model plays an important role in activities such as channel dredging, laying submarine cables and determining the maximum cargo weight for ocean-going vessels to prevent them from grounding along their route.

STW Technology Foundation project

The offshore industry, shipping, waterway and coastal management are all in need of an accurate and easily accessible reference surface at sea and the description of the position of that surface in relation to the Amsterdam Ordnance Datum. This STW Technology Foundation project will produce such a reference surface, which means it will be possible to join up the Netherlands and its coastal waters to the European Terrestrial Reference System ETRS89. 

Hydrodynamic model

The researchers in this project are going to do this by linking gravity data from various sources including the satellites GRACE and GOCE, radar height measurements and water level measurements from tidal stations on shore and at sea to a hydrodynamic model for shallow water, in a feedback loop. This model, together with a new geoid (the precise geometrical description of the irregular shape of the earth), is of great practical importance for users of the shore and seabed. 

More accurate data

A sound height reference system is also essential for research on rising sea levels, ecosystem studies, integrated coastline management and the proactive minimization of disasters. Ultimately it can pave the way to a more realistic, time-dependent representation of under keel clearance, in response to the growing demands in the shipping sector to load vessels as fully as possible. 

More information

“Vertical reference frame for the Netherlands mainland, Wadden islands and continental shelf (NEVREF)”, project leader Prof. Roland Klees, faculty of Civil Engineering and Geosciences, TU Delft, e-mail:, tel: +31 (0)15 27 85100.

You can find the complete press release on the STW website.