Leonardo da Vinci designed canal locks to manage water levels and raise or lower boats between sections of a canal.
While working in Milan, Leonardo studied canals, rivers, and hydraulic engineering. His notebooks include designs for lock gates and canal systems, including improvements associated with the navigation of the Adda River and the Martesana Canal. A lock uses gates to enclose a chamber: water is added or released until the boat reaches the level of the next section.
Leonardo did not invent the basic idea of a canal lock, and earlier lock systems existed in Europe and Asia. His importance lies in studying and refining hydraulic structures, especially their gates, channels, and practical operation. Claims that he invented every form of lock are therefore too broad.
A canal lock differs from an aqueduct, which carries water over an obstacle, and from a levee, which restrains floodwater. Leonardo’s hydraulic work connected mathematical observation with infrastructure used for transport and water management.