The Austerlitz underground reservoir in Paris

A wastewater storage facility to help the river Seine to be cleared up

Clearing up the river Seine in Paris is one of the municipality’s environmental objectives. To achieve this, one of the measures consists of building a large storage basin to reduce the discharge of wastewater into the river Seine during heavy rainfall. Artelia is in charge of project management and BIM management for the construction of this 49,500 m³ underground facility, the first and only storage-recovery basin in the inner city of Paris.


The saturation of the storage capacity of wastewater treatment plants is a well-known and major concern in the prevention of river pollution. When rainfalls are very heavy, wastewater treatment plants are not always able to store the huge volumes brought in by the sewerage networks, swollen by run-off water, and have to leave them to reach the natural environment without treatment. The construction of enormous storage reservoirs or storm water basins is one of the solutions used to prevent the water from reaching saturation point.

The municipality of Paris has decided to build an underground storage basin with a capacity of almost 50,000m³ upstream of the Austerlitz bridge, in a highly constrained urban environment. Artelia is in charge of project management and supervision of the construction of this infrastructure, which includes the reservoir itself (50m internal diameter), a drop shaft and concrete pipes, including a 625m-long pipe linking it to the sewerage network, which runs under the Seine and various other structures (viaduct, metro lines, etc.) and will require the use of a micro-tunneler. Our teams carried out all the design work using BIM and are also responsible for environmental monitoring of the site.