CT: There is potential energy stored in a water reservoir behind a dam. It is converted to kinetic energy when the water starts flowing down the penstock, from the dam. This kinetic energy is used to turn a turbine.
S: BC Hydro – https://www.bchydro.com/energy-in-bc/our_system/generation/electric_generation.html (last access: 22 July 2014)
N: 1. “water barrier,” early 14c., probably from Old Norse dammr or Middle Dutch dam, both from Proto-Germanic dammaz (cognates: Old Frisian damm, German Damm), of unknown origin.
2. Structure built across a stream, river, or estuary to retain water. Dams are built to provide water for human consumption, for irrigating arid and semiarid lands, or for use in industrial processes. They are used to increase the amount of water available for generating hydroelectric power, to reduce peak discharge of floodwater created by large storms or heavy snowmelt, and to increase the depth of water in a river in order to improve navigation and allow barges and ships to travel more easily.
3. Dams (are) erected across rivers (or valleys) to create artificial lakes and thus a head of water which can be used to drive a hydroelectric generating unit (dams also have use for flood control purposes, to make rivers navigable, or for water storage).
4. Basic types of dam are timber, earthfill, rockfill and masonry, of which gravity and arch dams are the two main sub-types.
5. The term dam is usually used for a structure constructed across a watercourse or stream channel, and dike for one constructed solely on dry ground.
6. dam: term standardized by ISO.
- Adj.: hydroelectric.
- Verb + dam: build, construct | breach.
- Dam + verb: burst | hold sth back.
- Prep. ~ across/on.
S: 1. OED – http://www.etymonline.com/index.php?term=dam (last access: 22 July 2014). 2. EncBrit. 3, 4 & 5. GDT. 6. TERMIUM PLUS. 7. http://oxforddictionary.so8848.com/search?word=dam (last access: 20 May 2015).