The Hollandse Ijssel storm barrier (1953-1958)

The  Hollandse IJssel – dammed up a century ago near Gouda and canalised over a length of 30 kilometers – is a waterway between Nieuwegein and Rotterdam and ends in the Nieuwe Maas. In the event of a flood, the river can hardly get rid of its water because the rising seawater stops the river water. Dangerous, because the area along the Hollandse IJssel is one of the lowest lying and most densely populated areas of the Netherlands: the Randstad.

In 1953 the dikes just about manage to withstand the force of the water. The fate of about one and a half million people hung in the balance. An expert compares the disaster night for the Randstad with ‘a herd of elephants passing through the eye of the needle’. Although it is known that the dikes are in poor condition, no action was ever taken. Something really has to be done now, according to the Delta Committee. The plan for the construction of a movable storm surge barrier and a large lock in the lower part of the Hollandse IJssel is launched.

Sliders

It is an extensive project. Two 45-meter-high towers are  built on both sides of the river. Sliders of 80 meters wide and 11.5 meters tall are suspended between these towers. These 635 tonne gates can be lowered into the water when extremely high water levels threaten to occur – more than 2.25 meters above sea level. In that case ships can continue their journey through the adjoining lock.

 

Because the barrier is only closed at extremely high water levels, shipping hardly suffers from it. This is important because the Hollandse IJssel is one of the busiest inland shipping routes to Germany. This is also taken into account, as much as possible, in the construction of a barrier and lock – which ultimately takes five years.

Hollandsche IJsselkering
Hollandsche IJsselkering

Dredging

By dredging part of the floodplain, ships can continue their journey without much hindrance whilst work is carried out on the river itself. Because the clay in the river bed is too weak to use as a base for the barrier, several clay layers are first dug away and replaced by sand from the Nieuwe Maas.

Subsequently, a construction pit is made using 100-kilometer-long steel sheet piles, from which the water is pumped out. Inside the pit, a threshold is created on the riverbed to support the heavy sliders when they are lowered.

Permanent link

Before the construction of the Hollandse IJsselkering, residents of the Krimpenerwaard often had long waiting times for the ferry to travel to the other side of the river. The construction of the storm surge barrier offers a good opportunity to realise a permanent link across. A bridge is built over the lock and the gates of the barrier. The bridge is now part of the N210 road.