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REINFORCEMENT OF ALLIÉS BREAKWATER AT DUNKIRK: SECOND RESANDING PHASE STARTED
20th february 2014

Built in 1876, the Alliés breakwater is an important structure which performs two functions simultaneously:

• It guides the continental floods of the drainage district for discharge at sea, by gravity or by means of pumping stations at high tide.
• It protects against seawater flooding.
It is a key structure which protects nearly 40,000 people from flooding in the Dunkirk area. It also protects the hinterland from the violence of the sea in case of exceptional storms.

With the experience gained in the operation and maintenance of its own marine and river structures, Dunkerque-Port has put its expertise at the service of the State which has appointed it as contracting authority for the works to reinforce and protect this structure, which is crucial to the safety of the population.

The first technical studies undertaken led to the drafting of a project for reinforcement and protection of the breakwater, comprising both the structural repairs to the breakwater itself, and adding protection by beach refilling, which will attenuate storm swells while resanding the bathing beach of Malo-les-Bains significantly.

After a first phase of resanding with approximately 300,000 m3, which took place under emergency conditions in the winter of 2011/2012, more in-depth studies served to define precisely the work to be carried out in the final phase and formed the basis for the administrative application in assessing the environmental impacts.

The second phase of resanding the beach in front of the Alliés breakwater has just begun. The contractor SODRACO was selected after a European call for tenders. The operation will involve moving nearly 1,200,000 m3 of sand. It will be accompanied by:
• the installation of windbreak nets designed, as in the dune areas, to hold the sand in place and combat the action of the wind (April 2014);
• the breakwater repair works (scheduled for 2015).

To reduce the nuisance caused by the works as far as possible (particularly access to the breakwater), it has been decided to use a large dredger. This means that the entire resanding operation should be completed in just over a month. The works to remodel the future beach will continue for approximately one month more.

As work will continue round the clock, a safety perimeter will be installed to prevent the public from entering the worksite. Noise measurements will also be taken near the closest dwellings to check that the disturbance caused, especially at night, does not exceed the levels acceptable to local residents. Information panels have been set up next to the Tixier barrier to enable people to follow the progress of the works.

Despite all this, we would draw the attention of the public to the importance of observing the safety measures put in place.

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