• 1600000 tonnes of rock
  • 60000 m³ of polluted sediments
  • 9 vessels

With a surface area of just 2.02 km² and containing 18,775 inhabitants, Monaco is the world’s most densely populated state. So, it should be no surprise that the Principality decided to expand its territory by reclaiming over 14 acres from the sea, while paying due consideration to the nearby nature reserves. The project includes both dredging, rock installation, land reclamation and environmental remediation works: a job fitting Jan De Nul like a glove.


"The complexity of the project requires extreme flexibility."

For the next three years (2017 - 2020), the vessels of Jan De Nul will be active off the coast of Monaco, in between pleasure yachts and the project site. The project consists of three stages: dredging, rock installation and land reclamation. During the dredging stage, which lasted from April to November 2017, the Envisan centre in Toulon played an important role as it had to process all polluted sediments.

Project manager Tom Van Slambrouck explains: “In a first phase, we removed an upper layer of 60,000 m³ (about 100,000 tonnes) of polluted sediments. Obviously, the fact that we could immediately process these sediments in our specialised Envisan soil treatment centre nearby was a bonus to the client. We also removed 30,000 tonnes of the existing shore protection, 120,000 m³ of remblai anthropique (construction waste dumped at sea) and 400,000 m³ of ordinary sediments.” 

Creating land

The second stage of the project started in December 2017. The final goal is to install 1,600,000 tonnes of rock, which will serve as foundation for the dyke around the actual land expansion. Tom: “These rocks are loaded onto our fallpipe vessel Simon Stevin in the port of Fos, near Marseille, in batches of 30,000 tonnes. With these rocks, the Simon Stevin builds the foundation very accurately. When all material is in place, our client, Bouygues Travaux Publics, installs a belt of caissons or huge concrete blocks on top of it, behind where the new plot of land will be created.”

Working within a very small area

It is not just the environmental requirements that turned this project into quite a challenge. Captain Jan van Vijven explains: “We are continuously working next to Monaco’s marina. To begin with, this marina is much more compact than an ordinary port. We must continually consider yachts sailing in and out as well as the fact that there are apartment blocks and hotels very close to our work area. You can imagine that tourists and residents who want to enjoy the peace and quiet and the lovely sights at sea don’t want to be disturbed too much. That is why we can only work between 6 am and 10 pm, which makes our planning even more restricted than usual.”

Another challenge is that the various large vessels of Jan De Nul are not the only vessels that are active in the work area. Survey boats are going back and forth, the environment department Mared is at sea with a boat, our client Bouygues is working on different locations and so are other contractors that also send divers into the water on regular occasions.

"This considerably increases the complexity of the project and requires extreme flexibility from our side", tells Jan us.“Still, I kind of like such challenges. I must say we have a top crew on board and a very fine team working on land. The mutual consultations are going really smoothly, which is crucial for such a project.”

Superintendent Rodolphe Dienst can confirm: “This is my first project for Jan De Nul and from an organisational point of view it has been a complex challenge from the beginning. We are really exploring the limits in terms of planning and the capacity of our vessels, so it gives great satisfaction when tasks are completed successfully.” 

Related articles

Doing more with less space: not just in Monaco!

Diegem, in the Flemish periphery around Brussels, and on the Brussels – Antwerp axis, is near the national airport of Zaventem. It goes without saying that, in an area of such national and international economic importance, space is scarce and…

Read more
Envisan treats the dredged sediments

In 2015, Envisan opened a soil and sediment treatment centre in La Seyne-sur-Mer, near Toulon (France). Here, polluted sediments from Monaco are remediated ready for reuse. Hannes Van den Berghe coordinated the activities between Envisan and the teams…

Read more
Giant muscles and red corals

Next to the project site in Monaco, there are two nature reserves with red corals, giant muscles and sea grasses that cannot, be damaged or disturbed under any circumstances.  That is why, before the start of the project, a team of Jan De Nul’s…

Read more
Vessels conversions

Mimar Sinan and the Tiger For this first stage, several vessels have been converted. Tom: “One of the reasons for this is that we are working on a very small surface area. For instance, on the backhoe dredger Mimar Sinan we installed a special…

Read more
The Tiger, the real project hero

Jan De Nul’s added value for projects such as this is its extreme flexibility in searching for customised solutions. For instance, we completely converted the Tiger, a self-sailing split hopper barge, so as to be able to remove sediments in places…

Read more