The Route du Littoral coastal road: the major site in Réunion


The Nouvelle Route du Littoral coastal road is the most complex site Réunion has ever conducted. It combines strategic and technical innovation, an area of study of exceptional environmental quality and therefore extreme environmental responsibility. It is currently the most important project of this type in all of France or Europe.

This road axis is essential to the island’s economic life and to its some 900 000 inhabitants. In order to increase the current road’s capacity, permanently protect it from falling rocks, reduce the high accident rate under its current design and ensure its renewal because it is at the end of its life, the decision was made to create a coastal road by the Réunion region and the French State, co-funder of this great project alongside the European Union.

Logically, the eco-responsible specifications imposed on the site are particularly demanding. Biotope and its local partners were commissioned to define solutions to best protect the environment, and then to ensure regulatory compliance, through the establishment and monitoring of avoidance, reduction and compensation measures approved by the authorities.

The 147 compensation measures put in place, include

  • establishment of protective curtains against the suspended solids generated by the work, as well as strict control of site waste and the quality of the neighbouring waters, in order to maintain a good state of conservation of marine environments and especially of the coral reefs in the vicinity, which are regularly appraised by our professional diver-biologists to ensure the impacts are limited.
  • A curtain of bubbles is deployed around all the work sites with a high risk of noise in order to protect marine mammals that are particularly sensitive to noise, and so they can be seen under the best possible conditions. Additionally, the expanded site area is scrupulously “listened to” using hydrophones permanently whenever mammals are present or acoustic impacts (significant site noise) are expected. These devices are paired with ULM visual surveillance every day involving risky work, making it possible to prevent or suspend works pending more favourable periods. Biological monitoring is also done on the marine mammal populations concerned in a broader perimeter of project implementation.
  • Seabirds of high ecological value are also considered, particularly through careful work on lighting conditions and materials, and even a special lighting prohibition calendar during periods where the risks of related strandings are higher.

In mid-2018, following four years of work, this major maritime structure has kept its environmental commitments. Biotope, its partners and all of the stakeholders serving the site’s environmental performance observe that to date, the impacts measured are lower than anticipated in the study phase and for which appropriate measures were defined and implemented on a daily basis. Environmental monitoring is effective, the measures implemented correctly, and the results obtained so far are particularly encouraging.

It is now necessary to ensure that the site’s environmental vigilance and performance continue to respect the objectives set until complete delivery of this flagship project, which would then certainly be a particularly successful example in the field, of obvious international interest.

This project is regularly discussed in articles and reports, and learn more about the environmental component in particular, please read:


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