River that runs wholly or partly beneath the ground surface

Subterranean river

Subterranean river

A subterranean river is a <a href="/en/River" title="River" class="wl">river</a> that runs wholly or partly beneath the ground surface – one where the riverbed does not represent the surface of the Earth. It is distinct from an <a href="/en/Aquifer" title="Aquifer" class="wl">aquifer</a>, which may flow like a river but is contained within a <a href="/en/Permeable_rock" title="Permeable rock" class="mw-redirect wl">permeable</a> layer of rock or other unconsolidated materials. A river flowing below ground level in an open <a href="/en/Gorge" title="Gorge" class="mw-redirect wl">gorge</a> is not classed as subterranean.<a href="#cite_note-1" style="counter-reset: mw-Ref 1;">[1]</a>

<div class="shortdescription nomobile noexcerpt noprint searchaux" style="display:none" about="#mwt1">River that runs wholly or partly beneath the ground surface</div>
<figure class="mw-default-size wiki-thumb"><a href="/en/File:Burger_OtokKriznaJama.jpg" class="mw-file-description image media-thumb" data-hash="File:Burger_OtokKriznaJama.jpg"><img loading="lazy" src="//upload.wikimedia.org/wikipedia/commons/thumb/b/bd/Burger_OtokKriznaJama.jpg/290px-Burger_OtokKriznaJama.jpg" decoding="async" data-file-width="643" data-file-height="273" data-file-type="bitmap" height="123" width="290" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/b/bd/Burger_OtokKriznaJama.jpg/435px-Burger_OtokKriznaJama.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/b/bd/Burger_OtokKriznaJama.jpg/580px-Burger_OtokKriznaJama.jpg 2x" alt="Burger_OtokKriznaJama.jpg"></a><figcaption>A subterranean river in the <a href="/en/Cross_Cave" title="Cross Cave" class="wl">Cross Cave</a> system of <a href="/en/Slovenia" title="Slovenia" class="wl">Slovenia</a>. (Scale shown by people in photograph.)</figcaption></figure>
Subterranean rivers may be entirely natural, flowing through <a href="/en/Cave" title="Cave" class="wl">cave</a> systems. In <a href="/en/Karst_topography" title="Karst topography" class="mw-redirect wl">karst topography</a>, rivers may disappear through <a href="/en/Sinkhole" title="Sinkhole" class="wl">sinkholes</a>, continuing underground. In some cases, they may emerge into daylight further downstream. The longest subterranean river in the world is the <a href="/en/Sistema_Sac_Actun" title="Sistema Sac Actun" class="wl">Sistema Sac Actun</a> cave system in Mexico.<a href="#cite_note-2" style="counter-reset: mw-Ref 2;">[2]</a>

Subterranean rivers can also be the result of covering over a river or diverting its flow into <a href="/en/Culvert" title="Culvert" class="wl">culverts</a>, usually as part of <a href="/en/Urban_development" title="Urban development" class="mw-redirect wl">urban development</a>.<a href="#cite_note-heggen-3" style="counter-reset: mw-Ref 3;">[3]</a> Reversing this process is known as <a href="/en/Daylighting_(streams)" title="Daylighting (streams)" class="wl">daylighting a stream</a> and is a visible form of river restoration. One successful example is the <a href="/en/Cheonggyecheon" title="Cheonggyecheon" class="wl">Cheonggyecheon</a> in the centre of <a href="/en/Seoul" title="Seoul" class="wl">Seoul</a>.<a href="#cite_note-4" style="counter-reset: mw-Ref 4;">[4]</a><a href="#cite_note-5" style="counter-reset: mw-Ref 5;">[5]</a>

Some fish (colloquially known as <a href="/en/Cavefish" title="Cavefish" class="wl">cavefish</a>) and other <a href="/en/Troglobite" title="Troglobite" class="mw-redirect wl">troglobite</a> organisms are adapted to life in subterranean rivers and lakes.<a href="#cite_note-6" style="counter-reset: mw-Ref 6;">[6]</a>

Examples of subterranean rivers <a href="#Mythology_and_literature" target="_blank">also occur</a> in mythology and literature.

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. It is distinct from an aquifer, which may flow like a river but is contained within a permeable layer of rock or other unconsolidated materials. A river flowing below ground level in an open gorge is not classed as subterranean. 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. The longest subterranean river in the world is the Sistema Sac Actun cave system in Mexico. Subterranean rivers can also be the result of covering over a river or diverting its flow into culverts, usually as part of urban development. 