écluse à poissons

CONT: Fish passes usually take the form of fish ladders and fish locks. ... The Borland fish lock was developed in Scotland as an alternative to fish ladders. It operates on the same intermittent principle as a ship lock but is constructed as a closed conduit. Intermittent closure of the gates at the bottom causes the continuous flow through the lock to fill the conduit at intervals, and thus allows fish waiting in the bottom chamber to be raised through the height of the dam. The lock also serves at other seasons to flush young salmon down past the dam.