The dam consists of a barrier of concrete, stone or other material, which is built on a river, stream or channel to dam the water in its channel. Then this dammed water can be diverted to irrigation ducts or exploited for the production of mechanical or electrical energy.
In a dam it is possible to distinguish between the reservoir (the volume of water retained), the slopes (which limit the body of the dam), the floodgates (the mechanical devices that regulate the flow of water), the landfill (where the excess water when the dam is full) and the locks (which facilitate navigation through the dam), among other elements.
The dams can be divided into gravity dams (their own weight is responsible for resisting the push of water), breakwater dams (triangle shaped), inflatable dams and other types.
There is a historical debate about the construction of dams. On the one hand, those in favor affirm that man must control water to increase his well-being. Those who oppose it, on the other hand, maintain that dams are dangerous (their eventual rupture can kill hundreds of people) and involve major social changes (such as population displacements or the loss of archaeological sites) that are not justified.
The mechanical energy of the dams can be used directly, as the old water mills did, or indirectly, to generate electrical energy, as happens in hydroelectric power plants.
Three Gorges Dam
