Greening of quay walls in Amsterdam

Greening the quay walls in Amsterdam

Several years ago, the City of Amsterdam began building metal structures along hundreds of bridges and kilometers of quay walls because they were in poor repair. These temporary structures provide space for planting various species of wildflowers, shrubs and trees. TEFAB, specialists in consulting and customization, supplied the grout bags, non-woven geotexile and helophyte plants for the project "Greening of the framework walls in Amsterdam.

A thorough plan of action
To provide a green interpretation of some of these structures, Brugt Kazemier, Business Manager/Project Manager at SchreudersGroen B.V. of Amsterdam, was contacted. 'The city architect of Amsterdam wants to introduce a lot of green in the design and that requires professional knowledge.' says Brugt. The quality of the water in the canals is improving, but the latest measurements also show that a large amount of salt water is flowing into Amsterdam from IJmuiden. Together with an affiliated ecologist, we discuss the plan in detail. The result is a sophisticated, functional green design that simultaneously embraces the theme of biodiversity.

Grout bags and planting helophytes
Brugt explains: 'At that point you start the search for the most effective and appropriate solution for the site and that's how I ended up at TEFAB via the Internet. After a thorough explanation and tips from my own experience, it turned out that in addition to grout bags and geotextiles, the delivery of helophyte plants was also possible. I was surprised about this service but at the same time very enthusiastic, because the planting is very image-defining! TEFAB thinks along with you and also takes over work in this way, a good cooperation I call that'.

Application of grout bags in the project
The metal construction along the quay walls includes sheet pile walls and H beams and contains PVC tubes, which are placed at an interval of ± 3 meters. A building steel mat is applied to the sheet pile structure to allow climbing plants to grow. The space between the sheet piling and the quay wall is filled with sand to stay between 10 and 25 centimeters below the water level. Between the sheet pile walls and the H profile, towards the water's edge, there is an open space of 40 centimeters wide. Here PVC tubes are placed which are perforated at the bottom. The material in these tubes is specially selected for its functionality. From the geotextile, bags are sewn which are placed in the tubes. These bags are then filled with substrates and soil, in which the plants are placed.

'The grout bag is like a small pot, the water sits deep and naturally has to come up to be available to the plants. The water 'climbs' up, this is due to the capillary action of the soil particles in the grout bags. Thus, the grout bags cause the water to move higher into the tubes. Thus, the plants grow out better and stronger. It is only a small medium and if there is a lot of sun on it, the plants dry out and we want to prevent that with this. explains Brugt.

Biodiversity and nature development along the quays of Amsterdam

The plants supplied by TEFAB are helophyte plants, marsh plants that stand with their roots in the water and rise above the water's surface such as the Lisdodde (Typha) and the Rough rush (Schoenoplectus) which usually grows in brackish water. Brugt explains: 'You have to make a conscious choice when it comes to planting, especially when dealing with brackish water from the IJ. TEFAB also took the time to provide us with appropriate advice on this.'

In the sheet piling construction, at the level of the water line, there is a perforation in several places. This allows the water to flow in and out smoothly. These existing holes will be enlarged so that young ducks and birds can swim in and out more easily. 'We make these holes larger and behind the holes we remove sand, with this sand we fill the H-profiles. We are also putting artificial reefs in these holes. We put willow branches in these reefs so fish will breed in them. There are a lot of young fish swimming around at the moment. Then the result is that we get visits from herons, they are wandering around there looking for a meal! We have also planted willows at the top of the structure. You can already see that they are growing well. They will be pollarded willows, the branches, twigs and leaves of which, after pruning, will be fed to the elephants at ARTIS Zoo - in the heart of Amsterdam!' Brugt explains.

Reuse of materials

Nowadays, the reuse of building materials is very important. The structures last for 2 to 10 years and are then dismantled. The choice of grout bag material also plays a role here. The outgrown and stuck plants in the tubes are cut very short. Hooks with chains are attached to the tubes in order to lift the tubes out of the water. Then the tubes, including their contents, are suitable for reuse at another location along the quay walls. This is a form of sustainability that greatly appeals to SchreudersGroen B.V. and TEFAB.

Achieving a beautiful result together

The contact between SchreudersGroen and TEFAB is smooth. 'We have short lines, I always have quick contact. I also regularly call the TEFAB office during a project, that contact always goes smoothly too!" explains Brugt.

'The special thing about this project with TEFAB and the City of Amsterdam, is the way everyone works together. It is a piece of nature development, created to bring people in the city closer to nature. When I walk along the Kloveniersburgwal and I see the flowers, all the fresh green leaves, the nests of coots and ducks and the heron parading in search of fish, I feel proud. I see people stopping to take pictures because they think it's so beautiful. That's exactly the idea behind this project.
- Brugt Kazemier, Business Manager/Project Manager SchreudersGroen B.V. from Amsterdam.