NGE reinforces the safety of the Orédon dam in the face of extreme flooding for SHEM

A 19th-century building that needs to be brought up to standard

Located at an altitude of 1.850 meters, in the commune of Aragnouet, the Orédon dam was built between 1870 and 1883. Designed to evacuate floods of 50 m3/s, it must be adapted to floods linked to climate change and its evacuation capacity must be increased to 213 m3/s.

Within this framework, NGE will construct an underground spillway, a labyrinth weir, a collection trough, and excavate a 128-meter-long hydraulic tunnel lined with reinforced concrete, extended by a discharge system. Reinforcement and monitoring work on the existing dam are also planned.

A construction project in the high mountains, without interruption of operations.

The project presents significant challenges: access at high altitude, maintaining the dam's operation and the site's tourism activities, and respecting a sensitive natural environment. As the lead contractor for the consortium, NGE FONDATIONS is managing the work by leveraging several areas of expertise within the NGE Group: underground works for major projects and earthmoving operations for GUINTOLI, which is part of the Midi-Pyrénées Multi-trade region.

Ultimately, this new flood spillway will significantly improve the safety of the Orédon dam, secure the territories located downstream and ensure the long-term viability of a historic hydraulic structure.

This project is part of the dynamic of references carried out by NGE in terms of rehabilitation and reinforcement of hydraulic structures, like the interventions carried out on the Oule, Gnioure and Labarthe dams.

According to Marco LAPORTE, project manager at NGE FONDATIONS: “This project, located in the heart of the Néouvielle Nature Reserve, an exceptional site due to its location and the preservation of its environment, illustrates the ability of NGE teams to work on sensitive structures under demanding access and operating conditions. We are proud to contribute to securing a historic dam, essential for the region.”