Underwater "windmill"
Two British consultants have developed an underwater pump that can irrigate riverside fields without using fuel or causing pollution. The prize-winning turbine is easy to construct and can work continuously (Ceres 141, Vol 26, No 3).
Originally designed to harness the energy of the Nile to irrigate the desert areas of Sudan, the pump has a three-blade rotor that utilises the energy of moving water, just as a windmill uses wind. The underwater pump can be operated by a single person with little training.