Engineering and consulting services for Swedish lock project

With 100-year-old locks, it has been a long time since the Swedes last built such hydraulic engineering structures in the Trollhättankan Canal. To replace six old locks with new ones, lock expert Fokke Westebring and his team are being flown in on behalf of WSP Netherlands to advise and engineer in Swedish culture, environment and soil conditions. 

As a global provider of engineering and consultancy services in the fields of Transport & Infrastructure, Property & Building, Earth & Environment and Power & Energy, WSP, which has been operating in the Netherlands since 2021, is at home in many markets. One project in which the company's wide and varied expertise is currently being deployed is a major lock project in Sweden. The contract involves the renewal of six old locks in the Trollhättank canal between Kattegat near Gothenburg and Lake Vänern. Replacing the existing lock structures with new ones will make the passage from the sea to the lake "future ready. At the same time, lakeside businesses will remain accessible by water, thus anticipating the growing demand for more transport by water. This will prevent a lot of freight traffic over land. 

Lock expert

WSP in Sweden has won the contract from Trafikverket (the Swedish Department of Public Works) to design the new locks and waterway. It is also planning and handling the environmental surveys, permit application and preparing the contracts for the contractors. The goal is to give ships safe and smooth passage with the least possible negative impact on the environment and the existing locks. That means building the new locks next to the old ones and widening the river on that stretch. Since the Swedes have not built a new lock for decades, the project will draw on the vast knowledge and expertise of Dutch lock expert Fokke Westebring. He is involved in the project full-time and travels to Sweden several times a year.

Dutch expertise

"With our experience from the Netherlands, we guide the design process," says Fokke. "What is the best location, how do you design a new lock, which choices do you make first and which choices should be combined? Location is the first step, but after that it is good to combine, for example, the choice of door type and filling/emptying system. If you choose one type of door first, that sometimes excludes a number of fill/empty systems. These are choices you have to make early in the design process, while the choice for, say, the type of bollards and light poles is made much later."

In addition to the structural design for the lock in Vänersborg, Westebring and his team are making the fairway design for all locations. Even that raises questions. "How wide, deep and wide should the bends be so that the ships reach their destination safely?" continues Fokke. "We determine that, among other things, on the basis of the Dutch Guidelines for Waterways of RWS, which also contains guidelines on, for example, the dimensions of the braking and guidance structures per type of ship and waterway. Specific guidelines they don't have in Sweden." 

Three locations, three challenges

All three lock locations on the route have their own challenges. At Trollhättan, the greatest height difference has to be overcome at 32.5 meters. This is done by connecting three new locks.

In Vänersborg, the height difference is less challenging at 7 meters, but the new lock must be fitted into a historically and culturally important and environmentally sensitive environment. Here, determining the right location and good design of the outer harbors is important for the smooth and safe passage of ships.

At Lilla Edet, the incorporation is also challenging due to unstable clay slopes, a nearby hydroelectric plant and a strong current on the north side just before the lock. "This makes it difficult for ships to enter the lock safely," Fokke said. "As a solution, an innovative triangular-shaped lock was chosen. Normally ships pass through a lock in a straight line, but because the triangular lock allows ships to enter and exit the lock in different directions, a lot of space is saved in the waterways leading up to the lock. As far as we know, this principle has not yet been applied anywhere in the world for commercial shipping." 

The future

The three sites (a total of six locks) are each following their own path. "At Lilla Edet, most of the choices have already been made. At Vänersborg we still have to decide on which side the lock will be built, and at Trollhättan there are still some design choices to be made. There we will soon apply the insights from our experiences at the first two locations. Construction work is scheduled to start in 2027. By 2033 everything should be ready," concludes Fokke.   

Water Construction Day 2024

WSP will participate in the Water Construction Day at the Jaarbeurs in Utrecht on October 17, 2024. This annual event provides an overview of the latest developments and new projects in the hydraulic engineering sector. This year, the theme of the Waterbouwdag is (future-proof) hydraulic engineering. A subject that fits perfectly with the Swedish locks project. Would you like to know more about this project or other activities of WSP in the Netherlands? Then visit the booth or come and listen to the presentation given by WSP about this project.