Climate change: Port of Antwerp to improve storm defences in response to extreme weather
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Photo Credit: Jan De Nul
Grim warnings of greater flooding and more extreme weather to impact global coastlines were issued by the IPCC in its latest report released in February 2022. This may serve as a wake up call for many countries to improve their coastal defences, but Belgium is one nation that is ahead of the game. Its Agency for Maritime Services and Coast (MSC) has begun the process of constructing a new storm surge barrier to be installed in Nieuwpoort to protect against extreme storms caused by climate change.
Lydia Peeters, the Flemish Minister for Mobility and Public Works, said, “Nieuwpoort is currently still unprepared for the high-water levels that can occur during heavy storms. For the protection of Nieuwpoort, at the Flemish Authority we are currently investing M€58 in the construction of storm surge barriers in the Yser estuary.”
The barrier, which began construction in 2018 and is due to be complete in 2025, will protect 67 km of coastline that is more vulnerable to flooding and experiences large volumes of maritime traffic. It will be able to cope with water level rises of up to 8 metres, typically a situation that would occur once every thousand years, but becomes more necessary when planning for unprecedented extreme weather events that have become more common in recent years.
With Belgium and Germany still recovering from unprecedented floods in July 2021, the surge barrier and Coastal Master Safety Plan are deemed essential to mitigate future loss of life, damages, and repair costs and will act as a safety measure until 2050.
The contract to build the storm surge barrier has been awarded to Jan De Nul in cooperation with Herbosch-Kiere.Dirk Van Rompaey, director of Civil Engineering Works at Jan De Nul Group, described the project as “a unique hydraulic structure in which civil engineering and maritime technology know-how and expertise join forces.”
While typical storm surge gates or flood barriers are fixed installations with gates or bulkheads that can be closed against storm surges or spring tides, the Belgium barrier design is somewhat unique. In the event of a predicted storm surge, it will rotate 90 degrees to hold back the water from the port.
The concrete threshold under construction measures 23.5 metres in width, 42.1 metres in length and five metres in height and is intended to hold the steel barrier in normal, open position.
With the concrete threshold enroute from Kallo to the Port of Antwerp by special transport, the impending installation and immersion will be a major milestone towards the completion of the project.
When asked about the measures in place to address how port traffic will be affected during the installation the Charlotte Devriendt, in charge of communications at the port of Antwerp said , “Most of the time, passage is possible for vessels. Sometimes there is a restricted passage. During the project, there are a few weeks that there is no passage possible at all. The restrictions are communicated to the users by a weekly mailing and in the specific app: Stormvloedkering Nieuwpoort”.
While the project could well have been delayed by the pandemic, Devriendt said “specific sanitary measures” ensured time critical work was able to continue and no significant delays occurred.
Stemming the tide
The installation and immersion is an involved and time-intensive process. Upon arrival in Port Of Ostend, the threshold is hooked onto a crane on a second pontoon, the Matador III. Moreover, the pontoon will be submerged so that the threshold is entirely covered by water, reducing the load to be lifted a lighter 1,210 tonnes. This entire operation will take 16 to 20 hours and once complete the installation will be assessed. Following this, the threshold will be suspended from the crane on the Matador III and will be ready for the last six-hour leg of the trip to Nieuwpoort.
Once the threshold has arrived in the harbour channel, it is lowered between two abutments,taking approximately 24 hours. Finally, the threshold will need to be anchored. During the whole process, divers are present to check the positioning.
The storm surge barrier in Nieuwpoort is just one of the projects in Belgium's Coastal Safety Masterplan. The agency for Maritime and Coastal Services is in the process of developing other various projects since 2011, including a storm wall at an at risk location at the Port Of Antwerp. The port of Antwerp said “In low-lying critical zones, [just] beach nourishments are sometimes not enough to reach the protection level. In that case we [must] build a storm wall or a storm surge barrier on the existing promenade. These storm walls can be mobile or fixed.”
The Port of Antwerp continues to take a proactive approach and is currently conducting research on how to further mitigate the impact of climate change on its operations. This includes looking into measures needed to protect the inner port of Ostend with a storm-stability assessment of all existing locks and dams in the harbours.
It is also conducting a pilot project to create dunes in front of a promenade to study the added-value of this natural solution to coastal safety.
Of course, the Port of Antwerp is not alone in seeking to minimise potential damage and loss of life from the effects of climate change. Other projects are underway in Europe, including the construction of a major flood barrier on the UK's southwest coast in Somerset. Bridgwater's US $125 million tidal barrier will begin construction in late 2023 and become fully operational by 2027. Located on the River Parrett in Chilton Trinity, Somerset, it will be one of England's biggest flood defenses. Similar to the Thames barrier, it will feature two vertical gates that can be closed against dangerously high tides and storm surge to stop water flowing into the river and overwhelming flood defenses upstream, protecting an estimated 13,000 homes and 1,500 businesses currently in the floodplain.
As the recent IPCC report underscores, time for such projects is of the essence as extreme weather events are already becoming a more common occurrence. Whether other ports and coastal areas around the world will soon follow similar proactive measures, or have the means to do so, remains to be seen.
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