Preliminary file for dredging works - Extension of the Port

Published on 15/09/2022
Categories: Commercial Port

Creations of the application file for the single environmental
environmental authorization.

Project financed by European funds

Preliminary file for dredging works - Extension of the Port
Project financed up to 1 680 000,00 Euros by the European Funds of Regional Development REACT-EU.

The studies launched by the Port concern the impacts related to the Commercial Port extension, with:
— The creation of a new 6 ha platform with 2 new quays (including a Ro-Ro)
— The creation of a cruise pier with the extension of the existing dike
— The dredging of the channel to a depth of -9 m with the reclamation of part of the sediment in the new quay, the rest being immersed in an area about 20 km west of the Port by deep water (500 m).

For this purpose, the Port has put together a team dedicated to the project which is composed of:
— Setec International for the drafting of the Preliminary Design (PD) and the Technical Design (TD)
— Cirrus Environnement as environmental consultant
The Gaïa - Terre bleue, Impact Mer, DHI, Bird & Bird consortium for the impact study
— Numerous service providers for additional field studies: Énergie de la Lune, Nortekmed, Quiet Ocean, i-Sea, Terra Maris, Marex, Eco-strategie, In-City, Antilles Géotechniques...

The realization of the impact study required an iterative and constructive approach, with the setting up by the Port of a Steering Committee, composed of the State administrations (Prefecture, DEAL, ARS...), the community and the users of the sea (RNN SM...). A Technical Committee was also set up with the State's referent organizations (IFREMER, CEREMA...) to support the port in its decisions on the choice of additional studies.

It was carried out :
— A bibliographic synthesis to build the initial state and define the needs for complementary campaigns
— A 3D numerical hydrosedimentary model to preselect an immersion site
— Geophysical surveys on the area chosen as a disposal site to validate it
— Underwater video surveys to verify the absence of remarkable or protected species on the selected site
— Currentological, wave and water quality measurements on the selected disposal site and in Grand'Baie to validate the digital model built
— Measurements of underwater noise in Grand'Baie to define the reference state and to feed the noise propagation model of the works for the impact study
— A reconnaissance of the Grand'Baie meadow by remote sensing and by underwater diving to qualify the limits of the meadow and define its state of conservation
— Inventories of corals on the harbor dike and on the riprap of the current embankment to count and locate protected species
— An EGES assessment of the works

All of the project's studies made possible to draw up the DDAEU in application of the regulations of the Environmental Code in force and to apply the ERC sequence (Avoid, Reduce, Compensate) appropriate to the local situation of the site.