Additional Information:

• Water wheel – Wikipedia
  A water wheel is a machine for converting the energy of free-flowing or falling water into useful forms of power, often in a watermill. A water wheel consists of a large wooden or metal wheel, with a number of blades or buckets arranged on the outside rim forming the driving surface.
• Watermill – Wikipedia
  A watermill or water mill is a mill that uses moving water as its power source. It is thus a structure that uses a water wheel or water turbine to drive a mechanical process such as milling (grinding), rolling, or hammering.
• Waterwheel Design and the Different Types of Waterwheel
  Hydro Energy is the technology that converts the energy of moving water into mechanical or electrical energy, and one of the earliest devices used to convert the energy of moving water into usable work was the Waterwheel.
• The efficiency of overshot and undershot waterwheels – Mark Denny – PDF
  The waterwheel evolved over two millennia to become an efficient machine. We analyse the physics of waterwheels, and construct simple models that show why the two most important types had very different efficiencies.