The development of public transport within the scope of the Grand Paris Express will reduce the ecological impact of commuting in the outskirts of Paris. The works will, however, produce great quantities of excavated soil which must be analysed before being transported to suitable storage or recycling spaces. This natural soil is not, however, always used at its true value and the whole process involves significant costs, both from economic and ecological points of view.
Through partnership with the conurbation of Grand Paris Sud Seine-Essonne-Sénart and the town of Ris-Orangis, Bouygues Travaux Publics Région Parisienne teams have found a positive alternative to this traditional system: an agricultural development project which integrates the best excavated soil and helps combine local attractiveness with enhanced quality of life.
Restructuring past agricultural land
The conurbation has a 13-hectare stretch of land in the town of Ris-Orangis, land which the conurbation and the town want to transform into organic arable land with the installation of a farm (hangar and accommodation) as well as irrigation drilling. The purpose behind this initiative is to consolidate a green belt around the municipality and operate it via local organic farming. The problem is that this plot of land was abandoned after being a small quarry and its degraded, very stony soil has a multiple composition, which means that it is not arable in its current state.
A convention was therefore signed in November 2018. In charge of carrying out proximity work on the Grand Paris Express, Bouygues Travaux Publics Région Parisienne will be modifying 7 hectares of land on the Ris-Orangis plot by using soil excavated from nearby worksites and selected for its quality.
A pilot project
Upgrading the land will involve four stages:
– recovering site topsoil cleared of stones;
– levelling the plot;
– selecting and bringing excavated earth needed for restructuring the soil;
– preparing the growing surface by re-using topsoil cleared of stones and fertilized through compost and green organic fertilizers.
All this work will be carried out in compliance with guidelines suggested by an agronomist specialized in agricultural soil. The Société du Grand Paris has also given its agreement to integrate the site as an outlet for Grand Paris Express excavated earth.
The project is scheduled for completion in October 2019. Several candidates for creating the agricultural holding have lined up. If they are selected, they will occupy a few hectares each and sell their produce in short circuits. In the end, they will be able to cultivate the plots by applying organic farming specifications with a view to obtaining certification.
The project for using excavated soil for reconstructing an organic farming plot is an experimental solution. This circular-economy approach could be duplicated on other larger sites.