Mega reclamation underway at Lynetteholmen
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Photo Credit: Bert Visser
At the beginning of 2022, construction on the largest ever reclamation project in Denmark began. Known as Lynetteholmen, an island area of about 275 hectares is to be reclaimed, creating a peninsula between Refshaleøen, a former industrial area in the harbour of Copenhagen, and Kronløbet, the access channel to the city's port. The Lynetteholmen project is spearheaded by development company, landowner and port authority By & Havn, which is 95% owned by the City of Copenhagen and 5% by the Danish state.
The work is part of the city's overall storm surge protection plan and will protect coastal and central urban areas against future flooding. Additionally, the new land will provide room for about 35,000 residents as well as allow for the beneficial and environmentally friendly reuse of surplus material of the many planned construction projects in and around Copenhagen, including the extension of the Metro network.
Two stage task
The reclamation is to be carried out in two stages; the first stage covers the area just east of Refshaleøen and the second stage consists of work to the area north of it. The construction work for stage one, which has already started, is scheduled for completion in 2023, while for stage two, the work will start in 2024 and finish in 2027. Further filling of the entire area with surplus material can take until 2070, depending on the progress of other projects.
The work will include dredging, sand filling, rock placement, sheet pile installation, and road construction. Both stages will see construction activities carried out that will generate demand for imports of marine sand and quarry stone. In an effort to offset costs and source materials in an eco-friendly manner, Lynetteholmen will welcome surplus construction materials from other sites which would otherwise have been disposed of. The companies will be expected to pay to deposit the material at the new site.
Rhode Nielsen participation
By the end of 2021, By & Havn had tendered two contracts for stage one of the project.
The first contract was awarded to the Danish construction company Per Aarsleff A/S. This contract is predominantly for the marine aspect of the project and comprises dredging, sand filling, quay wall construction, and stone works. The second contract was awarded to another Danish company Munck Havne & Anlæg A/S. The main component of the second contract is the construction of an access road, but it also includes several other civil works.
Per Aarsleff has appointed Rohde Nielsen to undertake the dredging and sand filling portion of the first contract. A total of 220,000 m3 of material must be dredged at the Lynetteholmen site, with 50,000 m3 placed in a confined disposal site at shore and 170,000 m3 relocated offshore due to contamination. These dredging activities involved the removal of soft soil from the construction site as well as the deepening of a local navigation channel. Boulder removal was also required.
For these activities, Rohde Nielsen deployed the bucket ladder dredger Ajax R, backhoe dredger Mjølner R, grab dredger Heimdal R and several split hopper barges. For the sand filling, a 6,000 m3 trailing suction hopper dredger (TSHD) Balder R was used to move the bulk of the 600,000 m3 of material. The company’s latest acquisition, a 2,700 m3 TSHD Ask R, was used to precisely place material for the creation of the new breakwater.
New additions to the fleet
The Ask R is one of two identical modern TSHDs that Rohde Nielsen commissioned in 2021. The second vessel is called Embla R. The sister ships are 85.4 metres long and have several environmental friendly features such as a Siemens BlueDrive Plus C system, a Selective Catalytic Reduction (SCR) system, and fine particle filters. These systems enable the vessels to operate with very low emissions.
The ships are split hull hoppers, which in combination with a very low loaded draught of less than 5 metres makes them extremely suitable for nearshore operations. Their standard dredging depth is 32 metres, but with an extended suction pipe equipped with a submerged pump, they can reach a depth of approximately 52 metres.
With a hopper capacity of 2,700 m3, they fit well into Rohde Nielsen's hopper dredging fleet which consists of two medium-sized 6,000 m3 vessels, the Balder R and the Njord R, and several smaller units, ranging from the 535 m3 Toste R to the 2,507 m3 Thor R.
Rising challenges
Despite work on the Lynetteholmen project being in its early stages, the project is already seeing some challenges. In February this year, By & Havn indicated to the Copenhagen Post that stage one is likely to cost 500 million Kroner instead of the planned 300 million kroner - almost doubling costs at a time when raw material prices are on the rise. The price of steel was cited as a particular factor for the increase.
Although the government is said to have funds set aside for contingencies and of course, there are the funds that will be generated from the fees for disposal of materials from other construction projects (which will be used in Lynetteholmen). It remains to be seen how much income and cost savings the latter will generate.
However, that is not the only fly in the ointment. The Danish government is also being sued by the local Klimabevægelsen climate organisation for what is claimed to be an in-adequate assessment of environmental impact. It is likely that the legal action will cause significant delays to the project, in addition to rising costs in legal fees.
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