Each of the swivelling arms consists of 15 million kilos of steel and rests on a hinge-foundation of 52 million kilos of concrete. A quarter of a million Dutch people have already visited the project. The New Waterway Storm-Surge Barrier is the final element in the Delta Works, a system of dams and barriers that now protect the coast of the Netherlands. If the barriers computer system detects signs of danger, the barrier walls are driven out into the New Waterway, where they are filled with water until they come to rest on a sill. The computer conducts an analysis every ten minutes to decide whether the meteorological and hydrographic situation provides grounds for doing so.
Shipping then comes to a halt.
In principle closure takes place fully automatically, but as a precaution a team of nine people are called out to oversee such an operation. On average ten ships pass between the arms of the barrier every hour. If Rotterdam has to be sealed off from the sea, this will cost the port some 5-10 million guilders a day. The Rotterdam Port Coordination Centre will give shipping four hours warning before the barrier is driven out into place. Ships will then still have two hours in which to pass through the barrier.