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When it comes to the environment, the new coastal road project on Reunion Island (Nouvelle Route du Littoral) is leading by example. This is the first time that a project of this type has so proactively taken environmental issues into account or implemented so many measures to safeguard wildlife.
Acoustic subsea screens - Crédits : Lise Provost Nortekmed
As project engineer, Egis is tasked with meeting several highly ambitious objectives in order to avoid, reduce and compensate for any impact caused, and commit specific resources to ensure that construction work does not harm the environment.
One such illustration of this approach is the initiative to control subsea noise and its effects, in particular on the site of causeway D1 near Saint-Denis.
Following studies that were developed as far as industry practice allows, we determined the best possible conditions in which to conduct work in view of the sensitivity of the natural surroundings of these species and their habitats. To do so, these were studied throughout entire biological cycles (a full year of inventorying and specific studies) and through detailed work on the eco-design of structures. Prior to each phase of noise-emitting work, we ensure that there are no cetaceans present in the surrounding area; this is monitored around the clock, seven days a week. To remain within our tough regulatory limits, we deploy substantial technical means such as acoustic subsea screens (curtains of bubbles) around the sources of noise. These noise thresholds are specified by German law, which is reputed to be the most stringent in the world.
The Pointe du Gouffre features a rocky coral outcrop of widely-acknowledged environmental value. Among the measures taken to preserve it, a buoy continuously monitors water transparency, while filtering booms have been deployed to control the suspended matter (SM) along the sensitive zone, running more than a kilometre in length. The supporting columns for the future viaduct were thus laid without any incidents to report thanks to these proven measures.
Since work began on the NRL, SM levels have never once exceeded the authorised limits! This a source of pride for us all, since it is an illustration of the effectiveness of the measures deployed and our ability to anticipate risks before starting any task. In addition to these protection solutions, six supporting columns were eco-designed in order to act as nursery zones and, further offshore, eco-reefs will be installed to guarantee sustainable ecological development in the whole of the project zone.
Another major challenge is to preserve seabird life from all forms of light pollution. The lighting installed on site must therefore take into account the resident bird species (Barau petrels, puffins, etc), in particular during fledgling periods, when young birds use the stars to find their bearings at night.
This means that lighting is prohibited for 50 days running from December to April to reduce the risk of groundings. The rest of the year, dark yellow coloured lights and pointed towards the ground to avoid attracting or disorientating the birds. And if in spite of all these precautions we discover a grounded bird, we immediately take it to the local bird protection association SEOR for emergency treatment.
On worksites, the contractors’ environment managers ensure that good environmental practices are adopted.
Through its presence on site and the contribution of specialist consultancies, Egis, the project engineer, ensures that contractors take the necessary measures and that they are effective.
The environmental project management consultant Biotope visits construction sites at least twice a month on behalf of the regional council. The project leadership body DORL centralises and analyses the different environmental data and transmits this information to the State administration.
The State environmental police authorities carry out discretionary, random and regular site inspections.
At least twice a year, the regional council presents an environmental report to the project’s technical committee made up of representatives of the government and the local authorities concerned.
A science committee, comprising independent experts is consulted whenever necessary on various environmental aspects of the project.