Upgrading Portage-des-Roches Dam

Project description

Following the new Dam Safety Law introduced in 2002, and following the flood of 1996, the CEHQ entrusted Cegerco with bringing the dam up to standard.
Begun in 2010, the project was to be done in two (2) stages (2010 and 2011 with winter shutdown) and consisted of raising the upstream by 1.3 meters in order to contain the maximum probable flood (CMP), to redo the downstream wheel thruster, to install an MTQ type slideway and to construct the building housing the new generator.

At the mechanical level, we replaced 9 old wooden overflow valves with new steel ones actuated using mechanical operators and installed 2 new cable valves located in the old ball passages.
Since part of our mandate consisted in the design of equipment, all stakeholders worked together to design a high-performance solution that met the needs.
In addition, diving work had to be carried out to repair the structure in order to ensure the sustainability of the dam.

The environment played a very important role in this contract. We had to take advantage of the low water levels, early in the spring, to install the wooden cofferdams upstream, thus allowing the civil and mechanical work defined in the contract. The construction of the structure, dating from the 1920s, forced us to take special precautions regarding the loads that we had to transfer to the deck. Finally, the proximity of water forced us to take all the necessary precautions against any risk of damage to nature caused by our actions.