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A subterranean river is a river that runs wholly or partly beneath the ground surface – one where the riverbed does not represent the surface of the Earth (rivers flowing in gorges are not classed as subterranean〔(William Herbert Hobbs, ''Earth Features and Their Meaning: An Introduction to Geology for the Student and the General Reader'', Macmillan, 1912, pages 182 and 189. )〕). It should also not be confused with an aquifer which may flow like a river but is contained within a permeable layer of rock or other unconsolidated materials. Subterranean rivers may be entirely natural, flowing through cave systems. In karst topography, rivers may disappear through sinkholes, continuing underground. In some cases, they may emerge into daylight further downstream. Some fish (such as the Amblyopsidae) and other troglobite organisms are adapted to life in subterranean rivers and lakes.〔William B. White and David C. Culver (eds), ''Encyclopedia of Caves'', 2nd ed, Academic Press, 2012, ISBN 0123838339, (p. 468. )〕 Subterranean rivers can also be the result of covering over a river and/or diverting its flow into culverts, usually as part of urban development.〔Richard J. Heggen: ''(Underground Rivers from the River Styx to the Rio San Buenaventura with Occasional Diversions )'', University of New Mexico.〕 Reversing this process is known as daylighting a stream and is a visible form of river restoration. One successful example is the Cheonggye Stream in the centre of Seoul. Examples of subterranean rivers also occur in mythology and literature. ==Natural examples== There are many natural examples of subterranean rivers. Among others: * The Cross Cave system in Loška Dolina, Slovenia includes 22 subterranean lakes * The Lost River in the Appalachian Mountains of West Virginia disappears underground and reappears as the Cacapon River * The Mojave River in southern California flows underground in most places * The Phong Nha-Kẻ Bàng National Park in Vietnam has an underground river flowing through its cave system * The Puerto Princesa Subterranean River on the island of Palawan, Philippines flows underground before emerging into the West Philippine Sea 〔 http://www.gov.ph/2012/09/05/administrative-order-no-29-s-2012/ 〕 * The Punkva in Moravian Karst, Moravia, Czech Republic underground river flowing through cave system - Punkva Caves and Macocha gorge. * The Santa Fe River in northern Florida drops into a large sinkhole in O'Leno State Park and reappears in the adjacent River Rise Preserve State Park, downstream * The Sistema Sac Actun is an underwater cave system near the Caribbean coast of the Yucatán Peninsula * The Río Secreto system of caves, formed over centuries by an underground river is located in the Riviera Maya, Yucatán Peninsula. 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「subterranean river」の詳細全文を読む スポンサード リンク
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