Leonardo da Vinci’s canal engineering included the miter lock, a movable-gate system for controlling water levels. He worked on canals in Milan and studied how locks could let boats pass between sections at different elevations.
A miter lock uses two gates meeting at an angle that points upstream. Water pressure pushes the gates together, helping them seal. Opening or closing the gates allows a chamber to fill or empty before a boat proceeds.
Leonardo did not invent every principle of canal locks, but his Milanese designs improved practical engineering and documentation. His notebooks record gates, channels and mechanisms associated with the Naviglio system. The miter-gate idea became fundamental to later navigation canals and remains common in modern lock construction.