Dredging of lock chamber of world’s largest sea lock gets underway

Dredging of the lock chamber of the new sea lock in IJmuiden has started. The lock chamber is currently still full of sand. In the coming months, 600,000 cubic metres of sand will be removed here to reach a depth of 18 metres.

In order to accommodate increasingly larger sea-going vessels, IJmuiden has been working on the construction of the largest sea lock in the world since 2016. The new lock will be 500 metres long, 70 metres wide and 18 metres deep.

The project is a joint venture between the Ministry of Infrastructure and Water Management, the province of North Holland, the municipality of Amsterdam, Port of Amsterdam and the municipality of Velsen. Contractor consortium OpenIJ is building the new sea lock on behalf of Rijkswaterstaat. The lock is expected to be commissioned in early 2022.

Dredging sand

The large quantity of sand, over 7 million wheelbarrows full, will be transported to a location on the North Sea. The sand will be dredged within the walls of the lock chamber using a cutter suction dredger, Van Oord’s Biesbosch. A mixture of sand and water is then transported via a long, partly floating pressure pipeline to a spray pontoon.

This pontoon, which lies in the access channel in front of the Noordersluis, has the function of accurately dumping the sand into a section of the waterway that has been deepened especially for this purpose. A trailing suction hopper dredger, the Shoalway owned by Boskalis, then picks up the sand from this deposit and transports it to a specially designated dispersal location approximately 13 kilometres off the coast.

The dredging work will continue 24/7 and is expected to last until mid-September. During the work, incoming and outgoing ships can use the Noordersluis unhindered. The surrounding area will also not be hindered by the work.

Picture: Van Oord’s cutter suction dredger Biesbosch (by Ko van Leeuwen).

Author: Mariska Buitendijk

Mariska Buitendijk is one of SWZ|Maritime's journalists as well as the magazine's copy editor.