The Achères quarry is a site measuring about 145 ha; its operation consists of extracting alluvial sand and gravel from the Seine valley. The operating license currently in force was issued for 30 years in 2009. It is adjacent to areas previously quarried and refurbished by GSM since the 1990s. In order to increase the operational value of the site, GSM invested in the construction of a new aggregate production facility commissioned in May 2013. Located on the banks of the Seine, its production capacity is 1 million tonnes per year of washed and calibrated sands; more than half is shipped by river to Paris.
The site is situated in a suburban area, at the heart of the communes of Achères and Andrésy, close to the towns of Poissy and Saint-Germain-en-Laye, on the banks of the Seine.
The main part of the quarry redevelopment works consist in partially backfilling the land in order to convert it into a river port platform with a water basin to be connected to the Seine (dock) by the future developers. Other areas are earmarked to become recreational green spaces for public use, with an ecological interest. The final topography to be restored must also play a role in the development of flood storage areas as a large part of the site is located in the floodplain of the Seine valley.
Before the quarry was established, the land was used for agricultural purposes with plots irrigated by wastewater from the city of Paris up until the end of the 1990s. The wetlands have been reabsorbed since the manure spreading ceased, leaving dry farmland and brownfield sites with low ecological value.
However, the site is close to a biodiversity reservoir in the Saint-Germain-en-Laye forest and its refurbishment includes a contribution to the local and regional ecological networks ("trame verte et bleue" green and blue infrastructure project).
As the commercial operation of the quarry is relatively recent, the refurbished areas have been limited to dry wooded fallow land approximately 4 ha in size.
In contrast, the operation of the quarry and the aggregate production facility generates new natural environments: slopes providing habitats for sand martins, damp ditches with helophytes allowing the biological filtration of storm water and providing a favourable environment for amphibians as well as the appearance of invasive exotic species (buddleia, primrose willow, Japanese knotweed, etc.).
Ongoing nature projects
The project at the Achères site involves the implementation of measures to manage and improve the biodiversity (birds, insects, amphibians, etc.) at the industrial site, in particular in the zone of the aggregate production facility located immediately behind the banks of the Seine covering the:
- Green spaces and surrounding areas;
- Wetlands of small size, including the peripheral ditch collecting run-off water from the platform
Biodiversity management and improvement measures are to be established and put in place.
These initiatives will also include an information and awareness programme for employees about the biodiversity and the sustainable ecological management of their workplace.