Dredging and Infra

Across the globe, DEME carries out a comprehensive range of dredging activities, including capital and maintenance dredging, land reclamation, soil improvement, port construction and coastal protection. These activities are executed with a fleet of specialized dredging vessels, various types of auxiliary vessels and earthmoving equipment. The segment also provides contracting services for marine infrastructure projects. This includes the engineering, design and construction of complex marine structures such as jetties, port terminals, locks and weirs, infrastructure works such as bored and immersed tunnels, foundation and marine works for bridges or other constructions in a marine or fluvial environment and civil works for harbour construction, dams and sea defences, canal construction, revetment works, quay wall construction and shore protection. In addition, DEME is active in the marine aggregates business, which includes the extracting, processing, storage and transport of aggregates. Finally, DEME provides maritime services for port terminals.

A deep understanding of the dynamics of estuaries and rivers

Successful maintenance dredging requires decades of experience and expert knowledge about the dynamics of rivers and estuaries. Sedimentation and siltation are a continual natural threat to navigation and the accessibility of ports.

We seek to minimise the environmental impact of any maintenance dredging project and always carry out our activities in respect of the environment, reducing overflow and limiting turbidity. Our smart dredging techniques support the natural processes and use the river’s dynamics to maintain accessibility.

We have performed maintenance projects along many of the world’s major rivers, making sure these vital arteries function as efficiently as possible. As well as working on access channels and inland waterways, we are also busy within ports and harbours, maintaining docks, turning basins and mooring berths.

Experts in coastal protection methods

The world’s population is expected to increase by 2 billion persons in the next 30 years, from 7.7 billion currently to a staggering 9.7 billion in 2050, according to the United Nations and coupled with that, half of the global population lives within 200 km of the sea.
As coastal areas become increasingly densely populated, coastal erosion protection and flood defence measures become even more crucial. And as climate change leads to a rise in sea levels and the melting of the ice caps, this global challenge is only made more acute.

DEME has the knowledge and experience needed to assist with this global issue. We are experts in a wide range of coastal protection methods such as the construction of hard sea defences such as sea walls, dykes, breakwaters; underwater bunds; fixed piers or open-piled jetties; sand traps such as groynes; coastal armouring with revetments, gabions, accropodes, as well as soft engineering solutions including sand dune stabilisation and beach nourishment.

Decades of experience in designing, engineering and constructing the world’s ports

In light of the global population increase, consequent demand for energy, and the exponential growth in world trade, ports worldwide are both expanding in numbers and extending. In recent years the maritime industry has seen the arrival of the ultra large container vessel. This new era has even led to giants carrying more than 23,500 TEU and this means ports have to adapt to serve these mammoth container ships.

DEME has many long-term relationships with port and harbour authorities in all corners of the globe. We aim to be a trusted partner and assist them with their planning and preparations, whether this involves an entirely new port or the extension of an existing facility.

DEME has decades of experience in port construction, from the initial feasibility study, soil investigation studies and environmental assessments through to the construction of dykes, breakwaters, quay walls and jetties.

Dredging guarantees sufficient depth and width in the access channel, turning basins and docks, and we always aim to maximise the possibilities for the reuse of sand and sediment. We work with our customers to ensure that the dredged material can be used to reclaim new land for example, which in turn minimises the environmental footprint of any port construction project.

As a leading port construction company, we pride ourselves on being able to offer integrated, sustainable solutions.

The ever increasing scale of large bulk carriers, tankers and container ships, and the continuous growth in world trade has made capital dredging an absolute necessity in recent years. New ports need to be created, and access channels, berths, docks, and turning basins have to be deepened and widened in order to meet the needs of the global economy.

DEME always performs capital dredging with a view to it being a sustainable, long-term development. Often projects are executed in sensitive estuaries so respecting the natural environment and biodiversity is crucial. Our ongoing fleet investment programme means we are continually looking at ways in which we can improve our dredging vessels - to limit turbidity, reduce overflow and ultimately, increase productivity.

Advantages of beach nourishment

Beach nourishment and coastal replenishment are soft alternatives to hard coastal defences such as flood barriers, groynes and dykes. Essentially, beach nourishment protects against flooding and erosion by dissipating wave energy. We aim to work with nature to provide innovative solutions to ensure that the natural ecosystem remains in balance.

In light of our focus on sustainable, nature-based techniques, DEME is involved in a project for example to test whether biogenic reefs (shellfish, marine flora, sand mason worm reefs) have the capacity to reduce erosion and even storm waves. This project recognises the increasing need for coastal flood defences as sea levels rise due to the impact of global warming.

Additionally, when beach nourishment or near-shore replenishments projects are underway, we also make sure we limit the disruption to the natural environment as much as possible by taking breeding seasons into account.

Our marine engineering experts have decades of experience carrying out coastal defence protection and port construction. This includes everything from designing and constructing breakwaters, dams, dykes and flood barriers to protect coastal communities to others, where we build quay walls and harbour dams for port construction and extension projects.

Creating new land sustainably

DEME is a renowned global player when it comes to land reclamation. Reclamation creates land for the future - new industrial sites, commercial and residential areas, ports, airports, recreational or nature habitats and artificial islands.

We take a great deal of pride in playing a role in the creation of new land and we always do so with an eye on the sustainability of any land reclamation project. For example, material from capital dredging projects can be used in major land reclamation projects, which limits the ecological impact.

For more than 100 years we have also been active in dredging, transporting and the processing of marine sand and aggregates for the European construction industry, with a dedicated fleet of specialist dredgers and several processing facilities.

Additionally, DEME has long-term, sand and aggregate concessions, spanning an area from northern Germany to the UK Continental Shelf to the French Continental Shelf.

We are also experts in sand and sediment improvement and compacting techniques, making sure that the land reclamation process or restoration project is carried out sustainably and cost effectively.

We can deliver both locks in canals and rivers, as well as the world’s largest sea locks. The design and construction of the New Sea Lock in Terneuzen, the Netherlands is a good example of this. This lock is 427 m long, 55 m wide and 16.44 m deep and is one of the largest locks in the world. Our expertise includes the replacement and renovation of existing locks and weirs.

DEME has an impressive track record in the design and construction of immersed tunnels. An immersed tunnel is composed of tunnel elements, constructed elsewhere and floated to the tunnel site to be sunk into place and then linked together. They are commonly used for road and rail crossings for rivers, estuaries and sea channels/harbours. Immersed tunnels are often used in conjunction with other types of tunnels, such as a cut and cover or bored tunnel, which is usually necessary to continue the tunnel from near the water's edge to the entrance at the land surface.

In the Netherlands, we are currently involved in the DBFM contract for the ‘A24 Blankenburg Connection’ which connects the A20 and the A15 and improves access to the Rotterdam region. The scope includes the design and construction of a highway with 2 x 3 lanes, a land tunnel, a deepened connection to the A20 highway, an elevated connection to the A15 highway and the Maasdeltatunnel, as well as an immersed tunnel, which measures approximately 1,700 m, including the access ramps.

We are a partner in the Femern Link Contractors consortium (FLC) which won three out of four contracts for the design and build of the Fehmarnbelt Fixed Link project - a 19 km long immersed road and rail tunnel between Rødby, Lolland, Denmark and Puttgarden, Fehmarn, Germany - in 2016.

Other historic immersed tunnels in which DEME was involved:

• 2nd Coentunnel, Amsterdam, The Netherlands
• High Speed Railway tunnels, Dordrecht, The Netherlands
• 2nd Beneluxtunnel, Rotterdam, The Netherlands
• Piet Hein Tunnel, Amsterdam, The Netherlands
• Rupeltunnel, Boom, Belgium
• Kennedytunnel, Antwerp, Belgium

DEME has an impressive track record in the design and construction of bored tunnels.

As a member of the COMOL5 joint venture, in 2017  we were awarded the design, build and the 15-year maintenance contract for the Rijnlandroute, which is a new road connection from Katwijk, via the A44, to the A4 at Leiden in the Netherlands. COMOL5 is responsible for the reconstruction of the Leiden West motorway junction and the construction of the 4 km long N434 road, which includes a twin 2.25 km bored tunnel with an external diameter of 11 m.

Other historic bored tunnels in which DEME was involved:

• Liefkenshoektunnel, Antwerp, Belgium
• Airport tunnel – Diabolo link, Brussels Belgium
• North-South Link, HSL, Antwerp, Belgium
• Pannerdenschkanaal tunnel for the Betuwe Railway, The Netherlands

Cut and cover is a method of construction for shallow tunnels where a trench is excavated and roofed over with an overhead support system strong enough to carry the load of what is to be built above the tunnel. We are your partner for the design and construction of such cut and cover tunnels.

Recent cut and cover tunnels in which DEME was involved:

• Spoorzone Delft, Combination Crommelijn, Delft, The Netherlands

The design and construction of quay walls and harbours are our core business. The immersion of caissons, as part of a quay wall, is also a specialty. We also use the more traditional methods of weight walls and combi-wall constructions. These structures are usually a part of complete solutions for port projects. We are involved in green field port developments, as well as brown field port expansion projects. Our aim is to deliver complete and integrated solutions - from design, to construction and maintenance.

Examples of these projects include:

• Offshore Terminal Rotterdam, The Netherlands
• Botlek Tank Terminal, Rotterdam, The Netherlands
• Deurganckdok, Antwerp, Belgium

Marine structures such as jetties, are necessary for the logistical handling of goods and materials in ports along waterways as well as for handling LNG, oil and bulk commodities.

We are a specialist in the design and construction of maritime structures. Our specialists can advise you and resolve your logistic issues concerning existing marine assets or those that are due to be constructed. Additionally in the Benelux, we can assist you with all the necessary permit procedures. We can design nautical simulations for ship movements or for mooring at jetties or quay walls.

Examples of jetty projects:

• Two jetties LNG Terminal Rotterdam, Maasvlakte, The Netherlands
• Jetty LNG Terminal, Dunkirk, France
• Jetty European Tank Terminal, Rotterdam, The Netherlands
• Jetty Abengoa Terminal, Rotterdam, Maasvlakte, The Netherlands
• Jetty Vopak Terminal, Amerikahaven, Rotterdam, The Netherlands

Stable constructions always start with a firm foundation and work often begins with piling, drilling or driving piles. We are experts in concrete piles or tubular, steel piles from small to large diameters or dimensions. This requires special skills and knowledge of the specific conditions in ports, along coastlines or in waterways. We have an abundant amount of this expert knowledge and experience  in-house.

We can assist with regular foundation works or those that are in more challenging environments,  on land and on water. Whatever your requirements we have the sophisticated and dedicated equipment and expert personnel.

We also provide construction elements for the foundation of wind turbines. Together with our other activity lines we can organise the specialised transport and manage the immersion of these elements.

Our expertise:

• Combi-walls
• Precast concrete piles
• Piling on land and water
• Steel sheet piles, tubular steel piles
• Own equipment with specialised personnel