Ijmuiden sea lock project nears completion

While the lock – the largest in the world – can accommodate larger vessels, it also introduces challenges, notably the influx of saltwater that threatens the canal’s ecosystem and drinking water supplies.

To address this, the salt dam will employ ‘selective extraction’ techniques to sluice saltwater back to the sea. A section of the Binnenspui Canal is being deepened to a depth of NAP -23 metres, allowing saltwater—heavier than fresh water—to accumulate at the lowest point. Engineers will install pillars and walls within this deepened section, creating a ‘letter box’ to manage saltwater flow effectively.

Engineering firm Witteveen+Bos was commissioned by Rijkswaterstaat to prepare the design and build contract and is advising Rijkswaterstaat during its execution.

Construction began in October 2022, and significant progress has been made, with the 27m-high pillars installed by Europe’s second-largest crane vessel, the Gulliver, in March 2024. This summer large concrete walls and necessary infrastructure will follow, ensuring the dam is operational by the end of 2024.

The project will also include four fish passages, enabling migration between the sea and inland waters, crucial for species like eels that rely on both environments.