HOME

TheInfoList




A water gap is a gap that flowing water has carved through a
mountain range A mountain range is a series of mountains ranged in a line and connected by high ground. A mountain system or mountain belt is a group of mountain ranges with similarity in form, structure, and alignment that have arisen from the same cause, usu ...

mountain range
or
mountain ridge A ridge or a mountain ridge is a geographical feature consisting of a chain of mountains or hills that form a continuous elevated crest for some distance. The sides of the ridge slope away from narrow top on either side. The lines along the ...

mountain ridge
and that still carries water today. Such gaps that no longer carry water currents are called
wind gap 250 px, Wind gap opened by an ancient stream on a Karstic terrain in the Ciudad Encantada (Province of Cuenca (Spain), Cuenca province) in Spain A wind gap (or air gap) is a gap (landform), gap through which a waterway once flowed that is now ...
s. Water gaps and wind gaps often offer a practical route for
road A road is a wide way leading from one place to another, typically one with a specially prepared surface which vehicles and bikes can use. Roads consist of one or two roadways (British English: carriageways), each with one or more lanes and any ...

road
and
rail transport Rail transport (also known as train transport) is a means of transferring passengers and goods on wheeled vehicle A vehicle (from la, vehiculum) is a machine A machine is a man-made device that uses power to apply forces and contro ...

rail transport
to cross the mountain barrier.


Geology

A water gap is usually an indication of a
river A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases, a river flows into the ground and becomes dry at the end of its course without reaching another body of water ...

river
that is older than the current topography. The likely occurrence is that a river established its course when the landform was at a low elevation, or by a rift in a portion of the crust of the earth having a very low
stream gradientStream gradient is the grade (slope), grade measured by the ratio of drop in elevation of a stream per unit horizontal distance, usually expressed as metre, meters per kilometre, kilometer or Foot (length), feet per mile. Hydrology and geology A hig ...
and a thick layer of unconsolidated
sediment Sediment is a naturally occurring material that is broken down by processes of weathering Weathering is the deterioration of rocks A rock is any naturally occurring solid mass or aggregate of minerals or mineraloid matter. It is cate ...

sediment
. In a hypothetical example, a river would have established its channel without regard for the deeper layers of
rock Rock most often refers to: * Rock (geology) A rock is any naturally occurring solid mass or aggregate of minerals or mineraloid matter. It is categorized by the minerals included, its Chemical compound, chemical composition and the way in w ...
. A later period of uplift would cause increased
erosion In , erosion is the action of surface processes (such as or ) that removes , , or dissolved material from one location on the , and then it to another location. Erosion is distinct from which involves no movement. Removal of rock or soil as ...

erosion
along the riverbed, exposing the underlying rock layers. As the uplift continued, the river, being large enough, would continue to erode the rising land, cutting through ridges as they formed. Water gaps are common in the
Ridge-and-Valley Appalachians The Ridge-and-Valley Appalachians, also called the Ridge and Valley Province or the Valley and Ridge Appalachians, are a Physiographic regions of the world, physiographic province of the larger Appalachian Mountains, Appalachian division and are ...
of eastern
North America North America is a continent A continent is any of several large landmasses. Generally identified by convention (norm), convention rather than any strict criteria, up to seven geographical regions are commonly regarded as continen ...

North America
. Alternatively, a water gap may be formed through
headward erosion in Marin County, California Marin County is located in the northwestern part of the San Francisco Bay Area The San Francisco Bay Area, popularly referred to as the Bay Area, is a populous region surrounding the San Francisco Bay, San Franci ...

headward erosion
of two streams on opposite sides of a ridge, ultimately resulting in the
capture Capture may refer to: *Asteroid capture, a phenomenon in which an asteroid enters a stable orbit around another body *"Capture" a song by Simon Townshend *Capture (band), an Australian electronicore band previously known as Capture the Crown *Captur ...

capture
of one stream by the other.


Notable examples

* Chicago Portage,
Illinois Illinois ( ) is a in the region of the . Of the fifty U.S. states, it has the , population, and the . is the state's largest city and the fifth with the capital in , located in the center of the state; other major metropolitan areas in ...

Illinois
-
Saddle Point In , a saddle point or minimax point is a on the of the where the s (derivatives) in orthogonal directions are all zero (a ), but which is not a of the function. An example of a saddle point is when there is a critical point with a relativ ...

Saddle Point
runs through the city itself. *
Columbia River Gorge The Columbia River Gorge is a canyon of the Columbia River in the Pacific Northwest of the United States. Up to deep, the canyon stretches for over as the river winds westward through the Cascade Range, forming the boundary between the state of ...

Columbia River Gorge
, Oregon and Washington, and
Wallula Gap Wallula Gap () is a large water gap of the Columbia River The Columbia River (Upper Chinook language, Upper Chinook: ' or '; Sahaptin language, Sahaptin: ''Nch’i-Wàna'' or ''Nchi wana''; Sinixt dialect'' '') is the largest river in the Pa ...
, Washington, United States *
Cumberland Narrows The Cumberland Narrows (or simply "The Narrows") is a water gap in western Maryland Maryland ( ) is a U.S. state, state in the Mid-Atlantic (United States), Mid-Atlantic region of the United States, bordering Virginia, West Virginia, and th ...
, Maryland, United States *
Delaware Water Gap The Delaware Water Gap is a water gap on the border of the U.S. states of New Jersey and Pennsylvania where the Delaware River cuts through a large ridge of the Appalachian Mountains. The gap constitutes the southern portion of the Delaware Wat ...

Delaware Water Gap
, New Jersey and Pennsylvania, United States * Heavitree Gap, Alice Springs, Australia *
Kali Gandaki Gorge The Kali Gandaki Gorge or Andha Galchi is the Canyon, gorge of the Kali Gandaki (or Gandaki River) in the Himalayas in Nepal. By some definitions, it may be one of the deepest gorges in the world. The upper part of the gorge is also called Thak K ...
- cuts through the world's tallest mountain range, the
Himalayas The Himalayas, or Himalaya (; Sanskrit Sanskrit (, attributively , ''saṃskṛta-'', nominalization, nominally , ''saṃskṛtam'') is a classical language of South Asia belonging to the Indo-Aryan languages, Indo-Aryan branch of the Ind ...

Himalayas
in Nepal *
Manawatu Gorge The Manawatū Gorge () is a steep-sided gorge formed by the Manawatū River in the North Island of New Zealand. At 6km long, the Manawatū Gorge divides the Ruahine Ranges, Ruahine and Tararua Ranges, linking the Manawatū and Hawke's Bay (region), ...

Manawatu Gorge
, New Zealand *
Potomac Water Gap The Potomac Water Gap is a double water gap in the Blue Ridge Mountains, located at the intersection of the states of Virginia, West Virginia and Maryland, near Harpers Ferry, West Virginia, Harpers Ferry. At , it is the lowest crossing of the Blu ...
, United States * Pongo de Manseriche, Peru * Pongo de Mainique, Peru *The
Middle Rhine Between Bingen am Rhein, Bingen and Bonn, Germany, the river Rhine flows as the Middle Rhine (german: Mittelrhein) through the Rhine Gorge, a formation created by erosion, which happened at about the same rate as an tectonic uplift, uplift in ...
in Germany *The Weltenburg Narrows on the
Danube The Danube ( ; ) is the List of rivers of Europe#Longest rivers, second-longest river in Europe, after the Volga in Russia. It flows through much of Central Europe, Central and Southeastern Europe, from the Black Forest into the Black Sea. It ...

Danube
in Bavaria *The
Iron Gates The Iron Gates ( ro, Porțile de Fier; sr, / or / ) is a Canyon, gorge on the river Danube. It forms part of the boundary between Serbia (to the south) and Romania (north). In the broad sense it encompasses a route of ; in the narrow sens ...

Iron Gates
on the
Danube The Danube ( ; ) is the List of rivers of Europe#Longest rivers, second-longest river in Europe, after the Volga in Russia. It flows through much of Central Europe, Central and Southeastern Europe, from the Black Forest into the Black Sea. It ...

Danube
, forming the border between Serbia and Romania


See also

*
Antecedent drainage streamAn antecedent stream is a stream that maintains its original course and pattern despite the changes in underlying rock topography. A stream with a dendritic drainage pattern, for example, can be subject to slow tectonic uplift. However, as the uplift ...
*
Defile (geography) In geography Geography (from Greek: , ''geographia'', literally "earth description") is a field of science devoted to the study of the lands, features, inhabitants, and phenomena of the Earth and planets. The first person to use the wor ...
*
Narrows A narrows or narrow (used interchangeably but usually in the plural form), is a restricted land or water passage. Most commonly a narrows is a strait A strait is a naturally formed, narrow, typically navigable waterway that connects two larg ...

Narrows
*
Peneplain In geomorphology incised into shale at the foot of the North Caineville Plateau, Utah, within the pass carved by the Fremont River (Utah), Fremont River and known as the Blue Gate. Grove Karl Gilbert, GK Gilbert studied the landscapes of this a ...

Peneplain
{{Rivers, streams and springs Structural geology Erosion landforms River morphology