GRTgaz’s “Traversées de Seine” project
GRTgaz is continuing to adapt and modernise its transport network in Normandy with the “Traversées de Seine” project. This consists of replacing two existing gas pipes with two new ones buried at greater depth under the Seine between Tancarville (Seine-Maritime) and the Marais-Vernier (Eure). This work will allow the Grand Port Maritime de Rouen to dredge the river to increase its depth, boosting river transport through the passage of ships with heavier loads and thus improving the port's competitiveness. Launched in February 2019 for a period of one year for an investment of €11 million, “Traversées sur Seine” is the largest project carried out by GRTgaz in the region.
The “Traversées de Seine” project consists of laying two 40 cm diameter pipes under the Seine over a total length of 630 metres. GRTgaz has opted to use the microtunelling technique. The two pipes, spaced 60 cm apart, will be installed in a single microtunnel. Construction will take place in summer 2019, more than seven metres below the Seine. This work will allow the Grand Port Maritime de Rouen to continue dredging the Seine while guaranteeing the safe supply of energy to the region. These arteries supply the industrial areas of Le Havre and Port-Jérôme.
The project also presents an environmental challenge, as it is located at the heart of the Boucles de la Seine Normande Regional Nature Park and on the edge of the National Nature Reserve managed by the French environmental organisation, Maison de l’Estuaire. GRTgaz has worked in close contact with these stakeholders, and is implementing 27 measures to limit the environmental impact of the site. For example, the schedule of works has been adapted to the wintering and nesting periods of the birds on the reserve. Likewise, the site facilities and right-of-way of the microtunelling areas have been installed away from the wet grasslands and outside of the nature reserve. All these measures are subject to continuous monitoring with the territory’s environmental partners.