Hydropower (or waterpower) harnesses the energy of moving or falling water. This is usually in the form of hydroelectricity from a dam, but it can be used directly as a mechanical force. The term refers to a number of systems in which flowing water drives a hydraulic turbine or waterwheel.
Prior to the widespread availability of commercial electricity, hydropower was used for milling, textile manufacture, and the operation of sawmills. Saint Anthony Falls is an example of a natural site with considerable potential for water power. During the last half of the 19th century, scores of grist mills were built at Saint Anthony Falls, taking advantage of the 50-foot drop in the Mississippi River. The concentration of mills burgeoned the city of Minneapolis.Hydropower - Wikipedia, the free encyclopedia