Climate solutions

Construction of a multi-species spawning ground in fast-f lowing waters

downstream from the Saint-Timothée skimmer, St. Lawrence River

Québec

As part of the restoration work at the Beauharnois–Les Cèdres

hydroelectric complex, the Englobe team successfully delivered an

innovative, sustainable, and exemplary project: the construction of a

multi-species spawning ground in fast-f lowing waters downstream from

the Saint-Timothée skimmer. This initiative was designed to compensate

for a portion of the aquatic habitat loss (nearly 69,000 m²) resulting

from the stabilization of the intake canal’s right bank, and the repair

of the Les Cèdres dyke.

Constructed in dry conditions during the annual lowering of the basins,

the spawning habitat was built using over 15,000 m³ of rock and

f iltration materials. Developed on Hydro-Québec land, the project had

minimal impact on nearby residents and enabled the involvement of

local contractors.

Englobe’s solution transformed a low-quality, fast-f lowing spawning

habitat into a high-quality, stable, and durable ecosystem covering

8,700 m². Carefully integrated into the site’s complex hydraulic conditions,

the artif icial spawning ground maintains a constant f low of 15.7 m³/s,

ensuring current velocities and depths that are conducive to f ish

reproduction. With a clean, minimally silted substrate and the presence

of 130 rocky islets, the site of fers optimal conditions for spawning; this

was conf irmed by the capture of thousands of eggs and larvae from

14 f ish species.

Englobe successfully combined innovation, technical expertise, and

environmental, social, and economic benef its to deliver a lasting aquatic

habitat for the region’s f ish populations. This project stands out for its

reproducibility and its signif icant ecological contribution to a basin lacking

in fast-f lowing spawning habitats; it is also a proof of concept of how to

“add a river within a reservoir.”

Introduction Environment Social Governance Appendix

27

ELEVATING CLIENT COLLABORATIONS – Sustainable service of ferings

Beauharnois, Québec

Learn more about this project.