Valley of the Bassée - pilot site - first flood control structure

The Bassée project is a pilot site and the first of 10 flood control structures to be built in the major river bed of the Seine in the Bassée valley. Its function is to temporarily store the waters of the Seine to enable the water level downstream to be lowered, thereby reducing the socio-economic damage caused by flooding in the Ile-de-France region. In addition to this hydraulic objective, the creation of this pilot site is also intended to enhance the ecological value of the Bassée wetlands (in particular by ensuring ecological continuity and restoring wetlands, creating hydraulic annexes, etc.). The hydraulic works to be created are as follows:

• Creation of a 400-hectare dyked area with a capacity of around 10 Mm3 (surrounded by around 8 km of dykes with an average height of 2.5 m above natural ground level)
• Supply by a pumping station to be built on a branch of the Seine, with a capacity of around 42 m3/s, to regulate the structure and receive the public;
• Construction of ancillary structures designed in particular to manage external seepage and watercourse continuity.

This project management service follows on from an initial project management contract awarded in 2016 and then terminated in 2022. The design studies were already carried out under this previous contract by another project management consortium. The services provided by the current project management team involve monitoring the execution of the works (15 different lots for the hydraulic engineering works) and are broken down as follows:

• APR: operation ownership phase.
• VISA: examination of conformity with the project and approval of the execution studies carried out by the companies.
• DET, management of the execution of works contracts.
• AOR, assistance to the project owner during acceptance operations. BRL Ingénierie's assignment focused more specifically on the civil engineering works (main pumping station and ancillary works) and hydraulic equipment (pumps, mechanical equipment, electricity), covered by 6 different works packages.