Leonardo da Vinci used miter gates in canal-lock designs to control water levels.
Miter gates are paired gates that meet at an angle pointing upstream. Water pressure helps press the two gates together, creating a seal. By closing the gates and changing the water level inside the chamber, boats can move between sections of canal at different elevations.
Leonardo worked on canal engineering in northern Italy and developed improved lock arrangements, especially for the Milan canal system. His studies addressed practical problems such as changes in water level, navigation, and the movement of gates. The basic miter-gate principle became a durable feature of canal engineering.
A canal lock is not simply a gate. It is a chamber with gates at both ends, allowing water levels to be raised or lowered. Sluice gates can regulate water flow, but the paired angled gates associated with Leonardo’s lock designs are specifically called miter gates.