Reservoir
Artificial lake created by a dam to store fresh water.
A reservoir is an enlarged lake behind a dam, usually built to store fresh water, often doubling for hydroelectric power generation. Reservoirs are created by controlling a watercourse that drains an existing body of water, interrupting a watercourse to form an embayment within it, excavating, or building retaining walls or levees to enclose an area to store water.
- type
- Artificial water storage
- common_uses
- Direct water supply, hydroelectric power, irrigation, flood control
- construction_methods
- Dammed valleys, coastal, bank-side, service, irrigation reservoirs
- notable_example
- Parakrama Samudra (Sri Lanka), Marib Dam (Yemen), Honor Oak Reservoir (London)
Lore & Background
The Kingdom of Kush invented the Hafir, a type of reservoir, during the Meroitic period; 800 ancient and modern hafirs have been registered in the Meroitic town of Butana. In Sri Lanka, ancient Sinhalese kings created large reservoirs for irrigation, with King Parākramabāhu I stating, 'Do not let a drop of water seep into the ocean without benefiting mankind,' and building the Parakrama Samudra.
Reader's Guide
Reservoirs are significant for their role in storing fresh water for direct supply, irrigation, and hydroelectric power generation. They are built in various forms: dammed valleys, coastal reservoirs near river mouths, bank-side reservoirs that store water from variable-quality rivers, and service reservoirs that hold treated potable water near distribution points. The construction of dammed reservoirs often requires relocating people, historical artifacts, or rare environments, as seen with the temples of Abu Simbel moved before the Aswan Dam created Lake Nasser. Coastal reservoirs are preferred in some regions because they do not use scarce land area. Service reservoirs help ensure water pressure and manage peak demand, and can reduce pumping costs by refilling when energy costs are low. The article notes a debate over irrigation reservoirs: opponents view them as a monopolization of resources that may worsen droughts, while proponents see them as a solution for sustainable agriculture until a more durable model emerges.
Did You Know?
- The Kingdom of Kush invented the Hafir, a type of reservoir, during the Meroitic period.
- Coastal reservoirs store fresh water on the sea coast near a river mouth and do not use scarce land area.
Frequently Asked Questions
What is a Reservoir?
A reservoir is an artificial lake formed when a dam blocks a natural watercourse, trapping fresh water behind it. It functions as a managed storage body that can be drawn on for a variety of human needs.
What are the main purposes of a Reservoir?
Reservoirs serve four primary roles: supplying drinking water, generating hydroelectric power, providing irrigation for agriculture, and mitigating downstream flooding. Many installations combine several of these functions simultaneously.
How is a Reservoir constructed?
The most common method involves damming a valley to create a contained basin, but engineers also build coastal, bank-side, and service reservoirs using retaining walls, levees, or excavation. The key principle is interrupting or redirecting a natural drainage path so water pools in a controlled area.
What are some historically notable Reservoirs?
The Parakrama Samudra in Sri Lanka and the ancient Marib Dam in Yemen are often cited as landmark examples of large-scale water storage. In a modern urban context, London's Honor Oak Reservoir illustrates how such structures integrate into city water infrastructure.
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