Slussar

Slussar are mechanical installations used to raise or lower boats between bodies of water that have different levels, typically along rivers and canals. A lock consists of a watertight chamber with gates at each end and a system of valves or sluices to control water flow. By filling or draining the chamber, the water level within the lock is adjusted to match the level of the water on the destination side.

Operation is straightforward but precise. A vessel enters the lock chamber from the appropriate water level, the gates are closed, and the lock fills with water or drains water from the chamber until the water level matches the target level. Then the opposite gates open and the vessel continues its passage. Locks may be equipped with sensors, signaling, and safety devices to manage traffic and prevent accidents. The size of a lock varies to accommodate different vessel dimensions, and some locks use mitre gates while others employ alternative gate designs.

History and purpose. Modern canal locks developed in Europe during the 18th and 19th centuries to enable reliable inland navigation across terrain with varying elevations. In Sweden, slussar are common on routes such as the Göta Canal and the Trollhättan Canal, where they connect lakes and rivers and facilitate commercial and recreational traffic. Locks continue to be essential for hydrological control and waterway connectivity, though their operation increasingly integrates modern automation and safety standards.

See also: canal engineering, tidal lock (for estuarine applications), inland waterways.