A dam is any barrier that blocks or slows the free flow of water in rivers or streams above or below ground.

Some dams are natural, created as the consequence of mud or rock slides,

or by the activities of animals like beavers. Others are human-made, built of many different types of material

for many different purposes, in many different

styles. In general, human-made dams are built to make better use of naturally occurring

sources of flowing water. Sometimes that means tapping into the movement of water to generate

energy. Sometimes it means diverting some portion of a river to a nearby lake,

human-made natural or augmented natural, for general human water supply purposes, for drinking,

showering, and the like. In some cases, dams are built to alleviate or diminish the threat

of flooding for local ecosystems or cities, and in some cases, they're built to alleviate or diminish the threat of flooding for local ecosystems or cities.

And in some cases, they're built to allow local populations to reclaim land,

to basically remove water from a particular area so the newly exposed dry land can be used for other purposes.

Within the context of dams and dam building, a reservoir is the natural,

augmented, or completely artificial lake that stores water that has been diverted from a usually

nearby stream or river. A floodgate is a giant door built into dams, which allow the folks operating

the dam to control its flow, so they can open doors when they want more water to make it through

the dam, close the doors when they want to slow or stop that flow, and or when they want to

divert more water away from the typical route of the

river to fill up a nearby reservoir.

And a levee, also called a dike, an embankment, or a floodbank, or stop bank, is a typically

lower-tech, dam-like structure that is essentially just a wall of earth or rock or earth and rock and other

supporting material that can guide the course of a river, contain a reservoir, or otherwise help

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