Civil engineering rehabilitation of the Bergerac dam

The works carried out were intended to strengthen the structures on the right bank of the Bergerac hydroelectric scheme: Treatment of watertightness defects in the debris-clearing canal by mortar and cement grout injections; Repointing of the upstream side wall, construction of an underwater containment wall, and mortar and cement grout injections; Repair of surface deterioration in the fish pass and pouring of a concrete slab.

Main technical features

The scheme consists of the submerged powerhouse on the right bank, a debris-clearing canal, a fish pass, a weir dam and an eel pass on the left bank. The powerhouse was built in 1968. Before that, the scheme served as a lock, when the Dordogne was still navigable (the embankment dates from 1850–1853). The fish pass dates from 1984, while the eel pass dates from 2010. The hydroelectric power plant is a run-of-river facility. It uses a maximum flow rate of 57 m³/s to operate its two fixed-blade bulb units, each rated at 725 kW.

Specific constraints

A reconnaissance dive was carried out to confirm the geometry of the deterioration, validate the selected techniques and establish the preliminary quantity estimates.