Der Hopperbagger Pedro Alvarez auf der Elbe
Under water

All ports must dredge

Whether it’s Bremen, Antwerp, Rotterdam, or Hamburg—all ports have one thing in common: to ensure that ships can enter and leave unimpeded, excess sediment must be dredged and removed on an ongoing basis. But how do other ports handle this? What’s the same, and what’s different?

Ausschnitt einer Europakarte im Bereich UK, Niederlande, Belgien und Deutschland mit Kreisen die Verbringstellen und Baggermengen symbolisieren sowie ein Tortendiagramm mit Baggermengen europäischer Staaten.
Transfer points for dredged material in the North Range. The larger the circle, the higher the quantity shipped. Data source: OSPAR

More than 100 million tons of sediment are dredged and shipped in Europe every year. And because all ports have to dredge, we have been in close contact with experts from other ports for years. We work together on many projects. Because although we are also in competition, there are many common challenges. We can learn a lot from each other, especially when it comes to removing excess sediment from the harbor basins and waterways.</p

<p>One thing we have in common is that the sediments must be tested for pollutants before dredging. The EU sets requirements for this, which are implemented by the federal states. The following applies to all of them: low-polluted sediments may and should remain in the water, while higher-polluted sediments must also be brought ashore in other ports.</p

<p>What happens to contaminated sediments varies, however. Hamburg and Antwerp treat them in special facilities. There, the polluted fine-grained silt is separated from the clean sand and dewatered. The METHA in Hamburg was the model for the AMORAS treatment plant in Antwerp. In Bremen and also in Hamburg, the sediments are dewatered in special fields. The dredged material is then deposited or recycled, for example in dyke construction or as sealing material. In Rotterdam, contaminated sediments are disposed of untreated in the so-called Slufter, a huge underwater landfill on the edge of the North Sea.

<p
Innenansicht der industriellen Baggergutbehandlungsanlage AMORAS in Antwerpen
AMORAS filter presses - Polluted silt is also treated in a large-scale plant in Antwerp. The model was the METHA in Hamburg.
Das Baggergut Slufter in Rotterdam mit Schlick und Prielen, einer Deponie und Windrädern
What looks like mudflats is actually highly contaminated harbor silt in a huge underwater landfill on the edge of the port of Rotterdam, the so-called "Slufter".
Der Hopperbagger Pedro Alvares auf der Elbe
In most ports, the large hopper dredgers do the main work in maintaining the water depths.
Ein Saugbagger im Hafen von Emden
Ships also sail through thin layers of silt in the Ems. In a port area that is closed off from the tides, the silt is even artificially kept in suspension with suction dredgers instead of being removed.

Another common feature is that the right excavator must always be used. In order to be able to react flexibly to the respective requirements, the equipment, especially the large hopper dredgers, is rented from specialized dredging companies. At most, smaller dredgers such as grab dredgers, dredgers on pontoons, washers or silt harrows are operated by the ports themselves, which is also the most economical way.</p

<p>Dredgers, which are often in permanent use, are maintained by many ports themselves. This is another thing they have in common: soundings must be taken before dredging. This determines where the depths are sufficient and where excess sediment needs to be removed. We also work together with other ports on this, for example in the "nautical depth" project with Rotterdam and Antwerp, which aims to determine exactly when a layer of silt needs to be dredged or when it is so thin that it can still be safely navigated through - like thick cocoa.

Once the sediments have been tested, and if they are only slightly contaminated, they are usually picked up with large hopper dredgers and returned to the water at other locations, which is standard international practice. Rotterdam uses a large area in the North Sea, just under 10 km off the coast, for this purpose. Around 5 million tons are dumped here every year. The pollution of the sediments is very similar to the dredged material that we bring into the North Sea in ton E3. Rotterdam sees the shipment as a sustainable improvement, as sediments are also urgently needed off the Dutch coast to protect against rising sea levels. Antwerp also uses dredged material as a resource. It is used to "feed" sandbanks in the Scheldt, which has a positive effect on the currents.</p

<p>The decades-long exchange with other ports makes it clear to us: Hamburg takes sediment management particularly seriously and is constantly looking for improved solutions. We set global standards when it comes to testing sediment qualities, investigating suitable dumping sites, handling contaminated dredged material and continuously monitoring the potential impact of our dredged material shipments. We are particularly transparent: our sediment analyses are published on our website at short notice, as are the scientific monitoring reports, impact forecasts and the annual reports on our water depth maintenance. And if any information is missing, we are here to answer your questions, e.g. via tideblog@hpa.hamburg.de.

A film by the SAT1 Regional editorial team also shows how sampling and dredging works in the port.

FAQ on dredging in the ports of Europe

FAQ on dredging in the ports of Europe

 

Whether Bremen, Antwerp, Rotterdam or Hamburg, the currents of the sea and rivers ensure that new sediment is constantly being deposited. This is why all European ports must regularly remove sediment from the harbor basins and waterways. This is the only way ships can arrive and depart safely. In total, over 100 million tons of sediment are dredged and transported from container ports in Europe every year.</p

 

 

Strict EU-wide regulations mean that ports in Europe face the same challenges: Sediments must be tested for pollutants in advance. Low-polluted sediments may remain in the water, while more highly polluted material must be treated on land or deposited. Sufficient suitable disposal sites must always be provided for this purpose.</p

 

 

The ports handle contaminated material differently:

  • Hamburg & Antwerp: Treatment in special facilities where silt and sand are separated and dewatered (e.g. METHA in Hamburg, AMORAS in Antwerp).
  • Bremen & Hamburg: Dewatering on special fields and subsequent landfilling or recycling, for example in dyke construction.
  • Rotterdam: Depositing the polluted sediments in a large underwater landfill in the North Sea (the "Slufter").

 

 

Yes. Despite the competition among themselves, many European ports regularly exchange information and work together on projects to learn from each other.

 

 

Depending on requirements,different dredging equipment is used. Large hopper dredgers, which are hired from specialist dredging companies, carry out the majority of the work involved in water depth maintenance. Smaller dredgers are sometimes operated by the ports themselves.</p

 

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