Leonardo da Vinci improved the miter lock for controlling water levels in canals.
A miter lock uses two gates that meet at an angle pointing upstream. Water pressure pushes the gates together, helping seal the opening. Leonardo applied this principle to canal engineering and helped develop practical designs for gates and water control in northern Italy.
His work is especially associated with canals around Milan, where waterways were important for transport, irrigation, and construction. Leonardo studied how water moved through channels and how locks could raise or lower boats between sections at different elevations.
The basic canal lock was not invented by Leonardo. Earlier forms existed in Europe and Asia, and the first pound locks in Europe predated his work. Leonardo’s contribution was the refinement and detailed engineering of water-control systems, including lock gates and canal layouts. The term “miter” refers to the angled meeting of the gates, not to a religious hat or a measuring instrument.