Hollandsche IJsselkering
The Hollandsche IJsselkering was the first major project of the Delta Plan; construction began within a year of the North Sea Flood Disaster.
This barrier in Krimpen aan den IJssel protects a large part of the Randstad, the lowest-lying and most densely populated area of the Netherlands. The Hollandsche IJsselkering is also known as the Algera Barrier, named after Minister of Transport and Water Management Jacob Algera, who initiated the Delta Plan. The barrier is closed when the water level reaches 2.25 metres above sea level. At that point, the pumping stations of the water boards are also required to pump less water into the Hollandse IJssel.
The Hollandsche IJsselkering in statistics
- Built between 1954 and 1958
- 200 metres long
- Four towers, each 45 metres high
- Two steel sluices, each 82 metres wide, 12 metres high, and weighing 480 tonnes
- Closes within half an hour, an average of 3 to 4 times per year
Origin
It was not without reason that the Hollandsche IJsselkering became the first Delta Work. In 1953, the dike at Ouderkerk aan den IJssel broke, and there was a real threat that a dike in Nieuwerkerk aan den IJssel would also fail. The area behind it was narrowly saved from a flood that would have made the disaster even worse. To better protect the area, the Hollandse IJssel had to be closed off. The location where the river flows into the Nieuwe Maas was a logical choice.
Closing the river with a dam was not an option. Shipping had to continue, and the river plays an important role in draining the hinterland. It had to remain possible to pump water from the low-lying land into the river, which would then discharge the excess water to the sea.
Therefore, a complex was designed consisting of a barrier with two sluices, a lock for shipping, and two bridges: a movable bridge over the lock and a fixed bridge over the barrier. When the barrier is open and the sluices are raised, ships can pass underneath, and the tides continue as normal.
Construction
The construction of the Hollandsche IJsselkering began in 1954. First, the riverbed had to be reinforced, otherwise, the heavy structures would sink into the mud. On the eastern side, a construction pit was created. Here, thresholds were made for the riverbed. These thresholds had to have a special shape to withstand the strong current. When the sluices are lowered, the water must squeeze through an increasingly smaller space. This makes the current stronger and could cause the surrounding soil to wash away. To carry out these works, the river was slightly diverted, allowing shipping to continue.
Next, the western construction pit was dug for the construction of the sluice. The sluice is almost 200 metres long, including the inner and outer heads. With the construction of the bridge, over which the N210 runs, the Krimpenerwaard was given its first permanent connection to the rest of South Holland.
In 1958, the Hollandsche IJsselkering was completed, but with only one sluice, which could only be lowered at the turning of the tide, when the current was at its weakest. Construction of the other Delta Works had also begun, and the planned second sluice was not a priority. It wasn't until 1976 that this second sluice was added. New techniques were applied, making it possible to lower the sluice even during flowing water, not just at the turning of the tide.
The bridge over the barrier, the Algera Bridge, was widened in 1988. In 2009, the entire complex was renovated.
