In the North Sea flood of 1953, breaks in the dikes and seawalls killed 1835 people and forced the evacuation of 70.000 more, 10.000 animals drowned and 4.500 buildings were destroyed. To prevent such a tragedy from happening again, an ambitious flood defense system was conceived and deployed, called the Deltawerken. This project was intended to improve the safety of the lower areas of the Netherlands against severe storms and flooding. Since more than 1 third of the nations land lies below sea level, this was no simple task. Dunes along the entire seashore were raised by as much as 5 meters, while the Islands in Zeeland province were joined together by dams and other large-scale constructions to shorten the coastline. The most sophisticated and famous of these dams is the Oosterscheldekering, which can be opened and closed to keep the sea at bay while preserving the salt water river delta for wildlife and the fishing industry. Gary and I visit the less known, but not less impressive Maeslantkering storm surge barrier near the port of Rotterdam. This storm surge barrier had to be located in the Nieuwe Waterway. This played an important role in the planning stage of construction as this waterway is the main route to the port of Rotterdam. Therefore a barrier like the Dutch Oosterscheldekering and the Thames barrier could not be constructed, as such a barrier would block the shipping route. The barrier that was built is connected to a self operating computer system which is linked to weather and sea level data. Under normal weather conditions the 2 doors themselves are well protected in their dry docks and a 360 meter wide gap in the waterway gives ships enough space without any inconvenience, but when a storm surge of 3.00 m above normal sea level is anticipated in Rotterdam, the barrier will automatically close. Four hours before the actual closing procedure will begin, in and out going ships are warned. Two hours before, the traffic in the Nieuwe waterway will come to a standstill, thirty minutes before, the dry docks that contain the gates are flooded. After this the gates start to float and two so called loco mobiles move the gates towards each other.
No comments:
Post a Comment