SPIE helps with 'Selective Withdrawal' at the IJmuiden sea lock in the Netherlands

Published on 30 January 2024

Rijkswaterstaat (the Directorate-General for Public Works and Water Management) has awarded the contract for the construction of the 'Selective Withdrawal' facility in IJmuiden to Van Hattum en Blankevoort. Together with SPIE and other partners, a structure will be created to counteract the increasing salinisation of the North Sea Canal.

Inaugurated in January 2022, the Ijmuiden sea lock improves access to the port of Amsterdam for large freight ships, replacing the Noordersluis lock, built in 1929 and at the end of life. 

SPIE is responsible for the mechanical engineering aspects of the contract. 

This project is a great way of contributing to one of the UN’s Sustainable Development Goals, namely the sustainable management of water. 

Salinisation of the North Sea Canal ”

When ships pass through the IJmuiden Sea lock, much more saltwater flows from the sea into the North Sea Canal than through the Noordersluis. This equates to around twice as much salt, or around 10,000 tonnes of salt in total, each time a ship passes through. Measures are needed to counteract this salinisation, because an increase in the concentration of salt has adverse effects on nature, agriculture, and horticulture.

Selective withdrawal ”

The solution is to selectively remove salt water via the Spui- en Gemaalcomplex IJmuiden. The Binnenspuikanaal now contains a concrete wall with an opening at the bottom — a sort of "underwater letterbox". The bottom of the wall is deepened so that the salt water, which is heavier, collects there. When water is discharged by the pumping station, the saltwater flows through this opening at the bottom, leaving the fresh water layers above it in place.

Work done by SPIE ”

As part of this project, SPIE is designing and developing the mechanical and steel components required for selective withdrawal. One example of this work is the drop gate. In order to allow maintenance vessels to pass into and out of the Binnenspuikanaal, the structure has to be navigable. A door that can open and close will therefore be installed in the middle of the concrete wall, creating a navigable opening. SPIE is responsible for the design, development and installation of this drop gate and its movement mechanism. 

The design work started in the second half of 2021. Works are scheduled to be completed by the end of 2024.