4 February 2021
When designing the passes, NHSL considered many parameters to reproduce the ideal fish migration conditions:
A constant flow in the area, with a speed that does not exceed 0.8 to 1.2 m/s.
A minimum water depth of 0.6 m during low-flow periods, and the width of each pass must be at least 5 m.
The passes will be created directly in the natural substratum found across the Île des Sœurs jetty.
Once these corridors are in place, instruments will be set up to:
Perform biological monitoring with fish counts.
Monitor the effectiveness of hydraulic conditions.
Over 40 species of fish live in the Greater La Prairie Basin (where the river widens between the Lachine Rapids and the Victoria Bridge):
smallmouth and largemouth bass
walleye and sauger
All of these fish tend to inhabit the river where the work is located.