You are looking at an overshot water mill - a type which was found to be most efficient where there was a small stream with an available head of seven or more feet (2 metres). Water is taken by a channel and drops down onto the wheel. It's weight then provides the power.
The watermill you are looking at is situated in Blue Ridge Parkway in Virgina. Although there are many sights to see in the park, Mabry Mill is the most sought out and photographed.
Now we are great fans of the Lake applet by David Griffiths but on this page we are not using it. Instead we are using the Dorian Gray II applet which is not quite as smooth. Using the Dorian Gray II applet you can use an animated gif as part of the scene and you can add sound too. Try stopping the music and clicking on the 'lake'.
You are Listening to "Arabesque" by Debussy.