- Traffic
Road traffic will not be affected. When the work is complete, the footpath in Meyrin linking the Maisonnex sports complex to the Chemin de la Berne will be reopened, with the route modified to pass around the new buildings. The footpath in Cessy will remain unchanged.
- Landscaping
Both sites will be landscaped and planted with around twenty local tree species.
- Noise
An acoustic survey of the future facilities has been performed and forms part of the planning permission requirements. Noise emissions will remain below the legal limits. All the new equipment for the HL-LHC will be installed either in surface buildings with soundproofing or underground.
- Water
In Meyrin, a new water retention tank was installed to regulate the flow of rainwater into the Nant d’Avril stream. A new monitoring station was set up (CERN has 27 water monitoring stations on its sites and the surrounding areas). A similar tank is already in operation in Cessy, regulating the water released into the Oudar. In Cessy, two water tables are located beneath the experiment site. The work will penetrate only the surface water table: a watertight, circular wall will first be installed to a depth of 15 metres to isolate the water table and make it possible to excavate inside it. The work will not penetrate the deeper water table.