A reservoir is an enlarged natural or artificial lake, typically created by constructing a dam across a river valley, designed to store water for various uses such as drinking water supply, irrigation, flood control, hydroelectric power generation, and maintaining river flows
. It functions by collecting and holding water during periods of high rainfall and releasing it gradually during drier periods to ensure a continuous water supply and reduce flood risks
. Reservoirs can be formed by controlling or interrupting a watercourse, excavating land, or building retaining walls to enclose an area for water storage
. They vary in size and complexity from small tanks in towns to large-scale impoundments like those behind major dams. Reservoirs also help regulate river flow, support ecosystems downstream, and provide water for human and industrial use
. There are different types of storage within a reservoir:
- Dead or inactive storage is water that cannot be drained by gravity and is mainly for sediment settling and aquatic habitat.
- Active or live storage is the portion used for flood control, power production, and water supply.
- Flood control capacity refers to the reservoir's ability to regulate water during floods
In a broader context, the term "reservoir" can also refer to natural hosts or environments where infectious pathogens survive and reproduce, known as natural reservoirs in epidemiology
. In summary, a reservoir is primarily a water storage system, either natural or artificial, essential for managing water resources, controlling floods, generating power, and supporting ecosystems and human needs
