Tide mill

A tide mill (also known as a tidal mill) is a specialized type of watermill powered by the rise and fall of tides. These mills are typically built in estuaries, tidal inlets, or other coastal locations where there is a significant tidal range.

The operation of a tide mill relies on the impoundment of water during a high tide. A dam, sometimes called a barrage or sluice, is constructed across a suitable tidal creek or inlet. As the tide rises, water flows through a gate or sluice into the millpond, a reservoir created behind the dam. Once the tide reaches its peak, the gate is closed, trapping the water within the millpond.

As the tide recedes, the impounded water is gradually released through a controlled channel, flowing over or under a water wheel. The force of the water turns the wheel, which, through a system of gears and shafts, provides the power to operate machinery. Typically, this machinery was used for grinding grain into flour, but tide mills have also been adapted for other purposes such as sawing wood, operating bellows for ironworks, or pulping paper.

Tide mills represent an early and innovative use of renewable energy, predating other forms of hydropower. They provided a reliable source of power in coastal areas, particularly where freshwater streams were scarce or unreliable. The use of tidal energy allowed for milling operations even when freshwater sources were subject to droughts or seasonal fluctuations.

Tide mills experienced their greatest popularity from the medieval period through the 19th century. They were particularly common in Europe and the east coast of North America. However, with the advent of more readily available and controllable power sources, such as steam engines and later electricity, the use of tide mills declined significantly. Many fell into disrepair or were converted to other uses. However, some historical tide mills have been preserved and restored as examples of early industrial technology.