Leonardo da Vinci developed sluice-gate designs for regulating water levels in canals.
A sluice gate is a movable barrier that controls the flow of water through a channel. By raising or lowering the gate, engineers can manage water levels, drain sections, and help boats pass through changes in elevation. Leonardo studied and improved such mechanisms while working on canal and hydraulic projects in northern Italy.
His notebooks contain detailed observations of water currents, channels, gates, and locks. These studies were connected with practical plans for improving navigation around Milan and other Lombard waterways. Leonardo was interested not only in machinery but also in the behavior of water as it moved around obstacles and through openings.
A sluice gate is not itself a complete lock. A lock is a chamber with gates at both ends that raises or lowers boats between water levels; sluices are among the control devices used in hydraulic systems.