Leonardo da Vinci proposed a miter gate mechanism for opening a canal lock.
Leonardo worked on hydraulic engineering in northern Italy and studied canals, water flow, and methods for moving boats between different water levels. His designs included lock gates that met at an angle, forming a V-shaped closure when water pressure pushed them together. This is the basic principle of a miter gate.
The arrangement is valuable because water pressure helps seal the gates rather than forcing them apart. When the lock is emptied or filled, the gates can be opened once the water levels on both sides are nearly equal. Leonardo's engineering studies helped refine practical canal infrastructure, especially around Milan.
Leonardo did not invent every component of the canal lock. Earlier locks existed in Europe, and the specific history of miter gates includes developments by other engineers. The important distinction is that a lock controls water level for boats, whereas a simple floodgate mainly regulates water flow without raising or lowering vessels.