Eureka Gold and Timber Company Undershot Wheel
This Waterwheel is a decorative part of the Grizzly River Run raft ride in the Grizzly Peak section of Disney California Adventure in Anaheim, California.
An undershot wheel must be much larger in diameter to create the necessary torque from the small amount of time the high-pressure jet of water is in contact with each bucket on the wheel. But they are avery bit as effective as their slower, over-shot counterparts that you see much more often. These wheels also required a higher head of water to create the high pressure required to drive the wheel.