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Interview with Gilles Calas,
director of infrastructure at ASF (Southern France Highways)

As part of the Grenelle environmental agreement, ASF committed to environmentally upgrading its highway network. What are the goals of this project?

As part of the "Green contract" that we signed with the State in 2010, we launched an action programme to improve the integration of our older infrastructure in the environment and notably to preserve water resources and protect terrestrial and aquatic biodiversity. In addition to installations to treat rainwater and retain accidental pollution, we started in 2011 an initial pilot programme to study the ecological operation of the zones crossed by our highways, assess the impact of our infrastructures, carry out the necessary work and monitor its effectiveness. This programme covered five departments (Charente-Maritime, Gironde, Hautes-Pyrénées, Drôme, Hérault) representing the various biogeographical regions encountered and different stages of progress in developing the FEN (French ecological network).

What are the concrete results in favour of ecological continuity?

In each department, several sites representing obstacles to the passage of terrestrial and aquatic animals were identified. Feasibility studies were run and the work carried out. In just two years, 25 projects were completed, including two eco-bridges for the passage of terrestrial animals over highways and 23 eco-ducts, i.e. small tunnels under highways for smaller animals. A model project for aquatic environments was the upgrade of a river crossing for the A7 highway in the Drôme department with the construction of a lateral passageway and a fish pass for a number of species such as eels and even beavers (see this article).

Who did you work with on these projects?

From the very start, we set up a scientific and technical committee comprising the various stakeholders involved in FEN implementation, i.e. scientists, the regional councils, Setra, Onema and ONCFS (national agency for hunting and wildlife). The committee oversaw the feasibility studies that were carried out by specialised engineering firms working closely with local, environmental-protection associations. Our highway network is 2 500 kilometres long and crosses many rivers and wetlands. That is why the collaboration with Onema was indispensable from start to finish, to identify the priority projects, provide technical support in selecting solutions and determining the critical parameters, and finally for ecological monitoring afterwards. We also called on the Ecohydraulic centre in Toulouse for their support concerning innovative solutions and research. Today, the contacts between our civil-engineering teams and the environmental sector have turned into a true partnership. Environmental protection is no longer seen as a regulatory millstone, but as an essential component in the design of our projects on the same level as geological studies, for instance.

You are now preparing a second environmental-upgrade programme. Among other projects is the work on two ASF structures on the Allier river that block the movement of salmon along the symbolic waterway...

The second programme includes approximately 75 new projects to improve our network. The zones have been identified, now the feasibility studies must be carried out. The experience gained during the first programme has put us in a position to effectively upgrade our two structures on the Allier river, which are indeed obstacles for salmon. We will soon launch a complex feasibility study that will include a third, nearby structure that belongs to the State, but has caused identical problems. This project will be one of the very first undertaken as soon as our planning contract is signed with the State.


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