Locks

Locks are mainly built in rivers and canals, although some maritime ports have built huge port extensions behind large locks. 

The main task of a lock and dam is to guarantee a minimum draft level of a portion of a river / canal for every season. The lock itself allows ships / boats to pass from one portion of the river / canal to the next portion. The difference in water level between both sides of a lock depends on the topographic characteristics of the river / canal, and can reach several meters.

Steel sheet piles are the most popular material to build locks. Most often, they serve as a temporary retaining wall or cofferdam for the construction of the lock itself, and are integrated into the final structure.