Leonardo da Vinci improved the canal lock with a pair of angled miter gates.
A miter lock uses two gates that meet at an angle pointing toward the higher water level. Water pressure pushes the gates together, helping them seal the opening. Leonardo studied and refined this type of canal technology while working on waterways in northern Italy, where locks were essential for connecting canals with different water levels.
The improvement was part of a broader program of hydraulic engineering. Leonardo designed canals, studied river flow, and considered ways to control water for transport and irrigation. His work built on earlier engineering practice rather than creating every component from nothing.
A miter lock is different from a simple sluice gate or a canal lift. The defining feature is the paired, inward-pointing gates that separate water levels and allow boats to pass through.