How A Lock Work
How a Lock Works
Boat Going Downstream


Boat enters the lock; gate
closes behind it.


Water is released downstream; water level lowers in the lock.


When the water level is low enough, the gate opens and the boat leaves the lock.

Boat Going Upstream


Boat enters the lock; gate closes behind it.


Water enters from upstream; water level rises in the lock.


When the water level is high enough, the gate opens and the boat leaves the lock.