Canoe passage for crossing dams

Several types of canoe pass exist depending on the uses (types of watercraft, skill levels, etc.), the characteristics of the site (topography, hydrology, land ownership, etc.), and the obstacle to be overcome: 

• chute (fixed or mounted on a float): the chute is a canoe pass with a smooth bottom and a cross-section generally close to a semicircle.  
• baffle pass: the bottom of the canoe pass is equipped with baffles to reduce flow velocities and maintain sufficient water depth for the watercraft to slide through. Different types of baffles exist (made of wood, steel or plastic). Thermoformed polyethylene baffles have the advantage of combining safety, functionality, cost-effectiveness and ease of installation.
• bypass channel: this is a canoe pass similar to a river, possibly with submerged weirs, used to overcome the difference in elevation over a more or less extended length,
• pre-barrages or successive pools: the drop to be overcome is divided into several small drops in a series of pseudo-pools that dissipate energy. The weirs, often formed by triangular notches, take into account the parameters required for the passage of watercraft (draft, width, etc.).

Some types of canoe pass can also be traversed by certain fish (depending on the target species) and are referred to as “mixed passes” (baffle pass, bypass channel and successive pools).

The choice of pass type, its layout and the definition of its technical characteristics require a specific study for each site, so that the structure enables the obstacle to be overcome with optimum safety.