Rijkswaterstaat needs millions of cubic metres of sand every year to maintain the Dutch coast. That sand comes from the seabed. Rijkswaterstaat asked Deltares to look at more than eighty areas in the North Sea to assess their suitability as borrow areas for nourishment sand and fill sand. But the extensive geophysical measurements and bore operations generated much more information. Never before has the bed of one of the busiest seas in the world been mapped out so extensively.