What is Hydropower?
Water's power is manifested in hydrology, by the forces of water on the riverbed and banks of a river. When a river is in flood, it is at its most powerful, and moves the greatest amount of sediment. This higher force results in the removal of sediment and other material from the riverbed and banks of the river, locally causing erosion, transport and, with lower flow, sedimentation downstream.
In India, water wheels and watermills were built; in Imperial Rome, water powered mills produced flour from grain, and were also used for sawing timber and stone; in China, watermills were widely used since the Han Dynasty.
Hydraulic power networks also developed, using pipes to carrying pressurized water and transmit mechanical power from the source to end users elsewhere locally; the power source was normally a head of water, which could also be assisted by a pump.
Where there is a plentiful head of water it can be made to generate compressed air directly without moving parts. A facility on this principle was built on the Montreal River at Ragged Shutes near Cobalt, Ontario in 1910 and supplied 5,000 horsepower to nearby mines.