The tide mill
Like water mills, tide mills are powered by water flow. However, unlike water mills, which harness the continuous flow of a river, tide mills are driven by the rising and falling tides. Tide mills are situated alongside dams that have been built across tidal inlets. As the tide comes in, water enters the mill pond through a one-way gate that closes automatically when the tide begins to fall. The stored water can then be released during low tide, providing enough energy to turn the wheel and grind the grain.