Micro hydro power is probably the least common of the three readily used renewable energy sources, but it has the potential to produce the most power, more reliably than solar or wind power if you have the right site. This means having access to a river or creek that has a high enough flow and fall to produce usable power for a good part of the year.
Many creeks and rivers are permanent, i.e., they never dry up, and these are the most suitable for micro-hydro power production.
A micro hydro turbine can take several forms, the most widely recognized of which would be the water wheel, used extensively for grain grinding up until the past century. Waterwheels are still used in some situations that do not require a fast-spinning turbine, such as for pumping water. However, other type of turbines have become quite common.