The discussions lasted years. A lot of water flowed down the river Elbe and back up again before the first tonne of silt could be excavated. Nevertheless, since summer 2019, work has not only been running smoothly, but also almost completely unnoticed by the public. This is because the results are hardly visible at all from the shore.
All the action is going on below the water’s surface: every day, large suction dredgers move vast quantities of sand from the shipping channel to the precisely defined underwater deposit areas. And where the bottom consists of heavy soils interspersed with stones, such as the till formed during the Ice Age, a backhoe dredger has to get to work. Although it only brings approximately one percent of the total excavated material to the surface, it takes at least 120 days due to its comparatively low output.
At the beginning of February 2021, three quarters of the dredging work had already been completed, according to information from the Federal Waterways and Shipping Administration (WSV). More than 21 million cubic metres have been excavated. 15 of the 18 construction phases have been successfully completed. Dredging the navigation channel does not require the entire section between the mouth of the Elbe at Cuxhaven and the Port of Hamburg to be excavated. The waterway will be deepened by a maximum of 2.42 metres – in some spots by only 1.50 metres or even less. Approximately 40 percent of the 136-kilometre waterway was naturally deep enough already and did not need to be altered.
Speaking of deep, container ships still haven’t stopped increasing in size. And they need a lot of room. At the end of 2020, Germany’s largest liner shipping company, Hapag-Lloyd, ordered six huge new ships with a capacity of 23,500 containers each for a total of $1 billion. These ships will be among the biggest in the world. They will be ready between April and December 2023 and will sail back and forth between the Far East and Europe, most likely also calling in at Hamburg.
For the crews, pilots, tugs and terminal operators like HHLA, these calls have become routine. Handling is also not a problem as there are 18 mega-container gantry cranes available at the Burchardkai Terminal alone, which are able to service ships with a width of 24 containers. This is even enough for the new Hapag-Lloyd ships.
Freighters have not just grown in length (by up to 400 metres) and width (60 metres) over the past few years, but also in depth. The Elbe shipping route was not ready for this, despite having been dredged repeatedly over the centuries. Some containers had to be left in Hamburg otherwise the outgoing ships would have exceeded the maximum permitted draught.
Once the dredging project is completed in summer 2021, container freighters with draughts of 14.50 metres (in salt water) will be able to serve the Port of Hamburg, depending on the tide. To do this, they will take advantage of the increased water levels during high tide when entering or leaving the port. Ships with draughts of up to 13.50 metres are allowed at any time, regardless of the tide. Depending on their weight, large carriers will be able to take hundreds more containers on board once the excavation work is complete – a big economic advantage for the shipping companies and the competitiveness of the Port of Hamburg.
A two-hour “starting window” has been calculated to allow one mega-ship with a draught of 14.50 metres to depart from each large port facility (Waltershof, Altenwerder and Mittlerer Freihafen) per tide. This means that in future, even with high traffic volumes, the world’s largest freighters will have more than the proverbial hand’s breadth of water under their keels.
Parallel to the dredging, the waterway from the mouth of the Elbe tributary, the Stör, to the port boundary is being widened by 20 metres to make it 320 metres. The experts are therefore justified when referring to “dredging the navigation channel” rather than “deepening the Elbe”. This means that in future, wider ships will be able to approach each other without any problems on this narrower section of the river.
Work on a similar passing place between Wedel and Blankenese was completed in mid-February 2021. The channel has been widened to 385 metres over an eight-kilometre stretch. Now, up to four mega-freighters with a combined width of 104 metres can safely pass each other per tide.
Professor Hans-Heinrich Witte, President of the Directorate General of the Waterways and Shipping Administration
All of this work has taken place and continues to take place under water. Nevertheless, the dredging does have effects that are visible from afar for sailors and tourists. As the path of the incoming ships in the passing place has shifted to the south, the leading light has also had to be relocated.
As it has done for hundreds of years, the leading light indicates the centre of the waterway to pilots and captains on board. Ships know they are in the centre when the light of the taller lighthouse (rear light) aligns or is exactly above that of the lower one (front light). For this reason, two new distinctive red and white striped lighthouses were built: the 32-metre-high front light off Blankenese and the 62.25-metre-high rear light at Mühlenberg marina. They now flash a white light in unison: two seconds on and two seconds off.
“Of course, dredging the navigation channel also has an impact on nature,” says Dr. Claudia Thormählen, project manager at the Waterways and Shipping Administration Office for Hamburg (WSA). “However, we are doing everything we can to compensate for this.” For example, several new shallow water areas with high-quality habitats have been created. Many tidal inlets and pools ensure that not only shipping and the Port of Hamburg benefit from the dredging, but also that a wide variety of plants, birds and fish profit from the new areas affected by the tide.