Vianney-Legendre Fish Migration Facility
The historic Richelieu River flows northwards over 115km, from Lake Champlain to Lake Saint Pierre on the Saint Lawrence River. There are two major obstacles to eel migration on this River : the Saint Ours Dam, 18 km upstream from the outlet, and the Chambly Dam , 70 km from the outlet. Downstream from the latter are the Chambly rapids and the remains of an old hydroelectric dam.
The free circulation of aquatic species is impeded in the Richelieu River since 1967, when an old dam made of rocks and wood was replaced with the current concrete dam. There are numerous endangered migratory species in the Richelieu River, such as the Copper Redhorse (Moxostoma hubbsi), the River Redhors (M. carinatum), the American Shad (Alosa sapidissima), the Lake Sturgeon (Acipenser fulvescens) and the American Eel (Anguilla rostrata).
The 180m-wide Saint-Ours Dam is a water level management facility. In 2001, a multi-species fishway and an eel ladder were inaugurated. The fishway consists of 16 successive basins with single vertical slits. In addition to the design, manufacture, installation and operation of the eel ladder, MILIEU participated in the fishway design and was commissionned by Parks Canada to establish the optimal parameters for the operation of the fishway.