What water-control structure did Leonardo da Vinci improve with a pointed double gate?

Leonardo da Vinci improved canal engineering with a pointed double gate, now called a miter lock gate.

In a miter gate, two hinged leaves meet at an angle pointing toward the higher water. Water pressure pushes the leaves together, helping the gate seal the lock chamber. Leonardo used and refined this principle in designs connected with Milan’s canal system, where locks allowed boats to navigate changes in water level.

Leonardo did not invent the basic canal lock from nothing. Earlier locks existed in Europe, and historians debate the exact extent of his engineering contribution. His importance lies in the detailed study and improvement of hydraulic structures, including gates, channels, and water flow.

The phrase “miter lock gate” describes the gate mechanism rather than an entire canal. It is also unrelated to Leonardo’s many studies of mills and water wheels, which addressed power generation rather than navigation.