A watermill or water mill is a mill that uses hydropower. It is a structure that uses a water wheel or water turbine to drive a mechanical process such as milling (grinding), rolling, or hammering. Such processes are needed in the production of many material goods, including flour, lumber, paper, textiles, and many metal products. These watermills may comprise gristmills, sawmills, paper mills, textile mills, hammermills, trip hammering mills, rolling mills, wire drawing mills.
Watermill of Braine-le-Château, Belgium (12th century)
Interior of the Lyme Regis watermill, UK (14th century)
Model of a Roman water-powered grain mill described by Vitruvius. The millstone (upper floor) is powered by an undershot waterwheel by the way of a gear mechanism (lower floor)
Roman turbine mill at Chemtou, Tunisia. The tangential water inflow of the millrace made the horizontal wheel in the shaft turn like a true turbine, the earliest known.
Hydropower, also known as water power, is the use of falling or fast-running water to produce electricity or to power machines. This is achieved by converting the gravitational potential or kinetic energy of a water source to produce power. Hydropower is a method of sustainable energy production. Hydropower is now used principally for hydroelectric power generation, and is also applied as one half of an energy storage system known as pumped-storage hydroelectricity.
The Three Gorges Dam in China; the hydroelectric dam is the world's largest power station by installed capacity.
Watermill of Braine-le-Château, Belgium (12th century)
Interior of the Lyme Regis watermill, UK (14th century)
Chief Joseph Dam near Bridgeport, Washington, is a major run-of-the-river station without a sizeable reservoir.