Inverted Siphon

inverted siphon [in′vərd·əd ′sī·fən]

(civil engineering)

A pressure pipeline crossing a depression or passing under a highway; sometimes called a sag line from its U-shape.

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Inverted Siphon 

a pressured water conduit laid under the bed of a river or channel, along the sides and bottom of a deep valley or ravine, or under roads to pass an intersecting current of water (channel). Inverted siphons are placed in water-supply, sewage, and irrigation systems and in hydroelectric power installations. A distinction is made between single-hole inverted siphons, which consist of a single pipe, and multihole types, with a round or rectilinear cross section. Inverted siphons are made of reinforced concrete (most commonly), wood, and steel.