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A barrage is a type of low-head, diversion dam which consists of a number of large gates that can be opened or closed to control the amount of water passing through the structure, and thus regulate and stabilize river water elevation upstream for use in irrigation and other systems. The gates are set between flanking piers which are responsible for supporting the water load of the pool created. While the term ''barrage'' is borrowed from the French word meaning a dam generally, its usage for such a structure in English is chiefly in Pakistan, India, Egypt, Iraq, and other countries in the Middle East.〔V. J. Zipparro, Hans Hasen, ''(Davis' Handbook of Applied Hydraulics )'', 4th Edition, p.12.1. Mcgraw-Hill, 1992. ISBN 978-0070730021〕 According to the World Commission on Dams, a key difference between a barrage and a dam is that a dam is built for water storage in a reservoir, which raises the level of water significantly. A barrage is built for diverting water, and raises the water level only a few feet; they are generally built on flat terrain across wide, often meandering rivers. Similar distinctions are used in Egypt, where it is noted: "In this system a "dam" is a structure that forms a reservoir for the storage of water during the annual flood period of the Nile in order to supplement the natural flow of the river during the low-water period; a "barrage" merely raises the river or canal level, when necessary, to the height required for adequate flow into the canals that take off above it.〔Raye R. Platt, Mohammed Bahy Hefny, (Egypt: A Compendium ), p.198, American Geographical Society, 1958. Retrieved 2014-12-03 〕 Barrages are usually larger than the headworks of irrigation and navigation canals, with which they are associated. Barrages that are commonly used to dam a tidal lagoon or estuary as a method to capture tidal power from tidal inflows are known as tidal barrages. == See also == * Diversion dam * Weir 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Barrage (dam)」の詳細全文を読む スポンサード リンク
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