Leonardo da Vinci designed canal-lock mechanisms to regulate water levels between connected sections of a waterway.
Leonardo worked on canal engineering in northern Italy, especially around Milan, where canals supported transport, irrigation, and water management. His drawings show lock gates and chambers that could admit or release water, allowing boats to move between different elevations. The system reduced the need for a canal to remain at one continuous level.
Leonardo did not invent the general idea of a canal lock, which had earlier examples in China and Europe. His importance lies in improving and documenting hydraulic designs, including mitre-gate arrangements and practical construction details. A lock is different from a sluice gate: a lock moves boats between levels, while a sluice primarily controls water flow.