Construction of the Bourg-en-Bresse stormwater tank

The consortium of Soletanche Bachy and Desertot has been awarded the contract to build a 6,500 m3 stormwater tank located in the north of Bourg-en-Bresse, together with all the necessary inlet and outlet engineered structures.


The associated storm spillway is the largest in the city’s wastewater system. It currently discharges 200,000 m3 of water annually into the neighbouring River Reyssouze. Construction of this stormwater tank will therefore have a major impact on the amount of water discharged into the pipeline network in wet weather. The new structure is also part of a wider urban redevelopment project for the Pont des Chèvres district.

At 19.5 metres in diameter, the stormwater tank will be excavated to a depth of 24 metres. The teams of Soletanche Bachy are working on a slab arch solution designed to eliminate the need for deep micropiles and significantly improve the overall scheduling of the project.

Soletanche Bachy is responsible for building the 82-cm thick diaphragm walling for the storage tank, which will be anchored at 38 metres, the 52-cm thick spill structure, and the civil engineering for the entire structure.

The teams of Soletanche Bachy will be involved until the end of the summer before handing over to the earthworks team, who will then be followed by civil engineering for completion in spring 2019.