Planning and design
The ‘wet’ part of the project included a maritime access and internal channel of the new port, internal and external protective breakwaters, two beaches and a bird island. A major concern was to what extent the new harbour would influence the flood channel of the Seine estuary. Apart from a number of compensating measures, the project was constructed in different phases in order to minimize the environmental impact.
The bird island was constructed south of the port extension, on a sandbank called “Banc du Ratier”, situated in the middle of the Seine main channel. Available knowledge about bird behaviour within the natural environment of the estuary was taken into account in the design.
For several reasons the island was given a complex geometric shape: it should be able to resist storms, comply as much as possible with the prevailing currents and provide optimal habitat to different types of seabirds. The resulting shape is an oval opening to the south. The hard rock revetment provided a different habitat for aquatic life in the otherwise soft-sediment estuary. The island was reclaimed with dredged material from the extension of the approach channel to the port.