Hydropower
Class
presentation
no. 14 on hydropower energy in
HTML,
in PowerPoint
A demonstration water wheel in the
Florida Tech Botanical Gardens

While it doesn't look like this, the water strikes the upstream side and flows underneath. This type is known as a "breast-shot" wheel because the water strikes partway up the side near the incoming water.
The actual appearance is in these photos. Here's an assessment, the stream hydrology, and a teacher's guide.
Conventional/Hydro/hydropower.htm updated 050301 by FRL