Construction of a spillway and fish pass as part of the upgrading of a dam and the creation of a small hydroelectric power station at Aubusson d’Auvergne (63)

Mission G2 Pro

Project owner : Communauté d’Agglomération de Thiers, Dore et Montagne

We were appointed by the Communauté d’agglomération de Thiers, Dore et Montagne to carry out the G2 PRO geotechnical assignment for the project to upgrade the Aubusson d’Auvergne dam.

The project involved widening the spillway, relocating the fish pass and creating a hydroelectric plant.

Our study enabled us to decide on foundation solutions for the structures, integrating the hydraulic constraints linked to the function of each element: exceptional loading of the spillway for events with a return period of 3,000 years, anchoring of the plant in the river bed downstream of the dam at the level of the hydraulic energy dissipation pit.

We proposed the construction of barbicans through the slab of the fish pass and through the invert of the spillway to avoid any risks of overpressure. Special measures were taken to isolate the plant site from the river: watertightness by means of jointed micropiles and installation of a pumping system.

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