I was able to find a small number of water wheels and turbines that make use only of the stream flow velocity to generate electricity. (builditsolar.com)
Only 13 of the 30 original water wheels, each about 30 to 40 feet in diameter, remained at the time of our visit. (theexpeditioner.com)
With the elephant, you could move it's trunk, changing the angle of spraying water to turn water wheels inside. (wccftech.com)