Hydropower is the capture of the energy
of moving water for some useful purpose. Prior to the
widespread availability of commercial electric power,
hydropower was used for irrigation, milling of grain,
textile manufacture, and the operation of sawmills.
The energy of moving water has been exploited
for centuries; In India, water wheels and watermills were
built; in Imperial Rome, water powered mills produced
flour from grain, and in China and the rest of the Far
East, hydraulically operated "pot wheel" pumps
that raised water into irrigation canals. In the 1830s,
at the peak of the canal-building era, hydropower was
used to transport barge traffic up and down steep hills
using inclined plane railroads. Direct mechanical power
transmission required that industries using hydropower
had to locate near the waterfall. For example, during
the last half of the 19th century, many grist mills were
built at Saint Anthony Falls, utilizing the 50 foot (15
metre) drop in the Mississippi River. The mills contributed
to the growth of Minneapolis. Today the largest use of
hydropower is for electric power generation, which allows
low cost energy to be used at long distances from the
watercourse.
