Talk Tunnel Euralpin Lyon Turin: a big railway infrastructure in alpine environment The challenge of respecting biodiversity

The international railway project between Lyon and Turin has an ambitious purpose: to limit the environmental impact across the Alps, while enabling the development of international exchanges, particularly for circulation of high capacity freight trains.

The cross-border section of this project, between Saint-Jean-de-Maurienne in Savoie (France) and Susa in Piedmont (Italy) is already under construction from the building site of Saint-Martin-la-Porte. To fully meet the main environmental objective, the building sites, necessary for the construction of the line, must cause the least amount of damage to the natural environment, in the greatest respect for the Alpine biodiversity.

Thus, the Contracting Authority, the French-Italian company Tunnel Euralpin Lyon Turin (TELT), implements concrete actions during the current construction phase in Maurienne, at Saint-Martin-la-Porte.

The current building site covers an area of approximately 25 ha spread over four sites, which have been chosen because already anthropised and highly reworked. However, fauna and flora inventories, realized on a total of 144 ha, have identified some sensitive issues for the natural environment, and in particular:

Regarding wildlife, these include the presence of protected species Natterjack toad (Bufo calamita), who had once some breeding sites in the areas of the building sites;

Concerning the flora, the challenge lies in the presence of Early tulip (Tulipa raddii) and Rocambole Garlic (Allium scorodoprasum) inside and close to construction areas.

Avoidance, reduction and compensation measures have been implemented, including:

For Natterjack Toads, several campaigns to capture individuals, during the breeding period, and before earthworks on building site platforms, have been realized by a specialized consulting firm in ecology (Biotope); the amphibian populations concerned have been evacuated and transported to safe areas, on which compensation pools (6 in total, distributed across a network along the Arc river) had previously been realized. Construction site areas have been appropriately closed to prevent recolonization by amphibians, and the puddles have been refilled.

About Tulips and Garlic, adjustments of the perimeters of site areas have been possible to avoid the destruction of a few plants. For groups of plants located in the middle of the grip of the site, a transplantation campaign has been conducted in partnership with the Alpine Botanical Conservatory who provided scientific guidance. In total, about 3500 Tulip’s bulbs and 650 Garlic’s bulbs have been transplanted to host parcels situated inside an area of 5 ha subject to restoration, maintenance and conservation of open natural habitats and typical shrub of Maurienne Valley.

On building sites, the respect for biodiversity depends also by the incessant fight against invasive exotic plant species (including Summer lilac and Himalayan fleece vine) and the maintenance of ecological corridors.

railway infrastructure, biodiversity, mitigation measures