Water Wheel Undershot

An undershot wheel is a type of vertically mounted water wheel, driven by water striking the paddles or blades at the bottom of the wheel. The term "undershot" refers to the water's impact on the lower part of the wheel. This design, sometimes called a stream wheel, is the oldest known type of water wheel, with the first recorded description by Vitruvius, an engineer from the Augustan Age. Compared with other types of water wheels, the undershot wheel is less efficient. It is best suited for locations where the water flow is strong enough to rotate the wheel. The faster the water flows, the faster the wheel turns, making it ideal for placement over fast-flowing rivers. Despite its lower efficiency, the undershot wheel has several advantages. It is easy to construct, simpler, and often more cost-effective than other designs. Additionally, it has a smaller environmental impact. Historically, these wheels were commonly used for turning millstones and performing other mechanical tasks.