Leonardo da Vinci designed water-wheel machinery to turn moving water into useful rotary power.
Leonardo made detailed studies of water flow, wheels, gears, pumps, and mills. His designs show how falling or flowing water could push paddles or buckets, turning a shaft that transmitted motion to another machine. Water power could operate mills, lift devices, or support industrial work without relying on human or animal muscle.
Water wheels were ancient technologies, so Leonardo did not invent the basic machine. His contribution was the systematic analysis and refinement of hydraulic mechanisms. His notebooks examined how wheel shape, water direction, gearing, and friction affected performance. Some drawings are theoretical studies rather than records of machines that he personally built.