Leonardo da Vinci designed canal locks to manage changes in water level along navigable waterways.
Leonardo worked on hydraulic engineering in northern Italy, especially around Milan, where canals supported transport, irrigation, and industry. His studies included lock gates and chambers that could raise or lower boats between sections of canal with different water levels. The system reduced the need for boats to pass directly over steep changes in elevation.
Leonardo is often credited with improving mitre gates, whose angled doors press together more tightly when water pushes against them. The basic canal-lock principle was older than Leonardo, but his drawings and engineering work helped refine hydraulic infrastructure in Renaissance Italy.
A canal lock is not the same as a dam or an aqueduct. A lock is a controlled chamber with gates at both ends; water is added or released so a vessel changes height. Leonardo’s contribution belongs to the practical engineering of canals rather than to a single completely new invention.