Dams are used to store water in artificial reservoirs, conserving the resource for human independently of natural runoff.
They have been essential for human development, for supporting agriculture and the drinking water supply of large communities. The cultural and political development of populations and empires has always gone hand in hand with the ability to manage the water resource, to regulate its use and to be able to manage it. The reservoirs can provide energy for industry sector, they store water to produce mechanical or electrical energy, they can ensure floods control and available water agains fires. Furthermore, the reservoirs can be built for navigation, transport, environmental and recreational purposes. The availability of energy from hydropower source has supported worldwide the industrial development, the electrification of railways and the reduction of coal for energy production with enormous environmental benefits.