A ravine is a

landform A landform is a land feature on the solid surface of the Earth or other planetary body. They may be natural or may be anthropogenic (caused or influenced by human activity). Landforms together make up a given terrain, and their arrangement ...

that is narrower than a canyon and is often the product of

stream A stream is a continuous body of water, body of surface water Current (stream), flowing within the stream bed, bed and bank (geography), banks of a channel (geography), channel. Depending on its location or certain characteristics, a strea ...

bank

erosion Erosion is the action of surface processes (such as Surface runoff, water flow or wind) that removes soil, Rock (geology), rock, or dissolved material from one location on the Earth's crust#Crust, Earth's crust and then sediment transport, tran ...

. Ravines are typically classified as larger in scale than gullies, although smaller than

valley A valley is an elongated low area often running between hills or mountains and typically containing a river or stream running from one end to the other. Most valleys are formed by erosion of the land surface by rivers or streams over ...

s. Ravines may also be called a cleuch, dell, ghout (

Nevis Nevis ( ) is an island in the Caribbean Sea that forms part of the inner arc of the Leeward Islands chain of the West Indies. Nevis and the neighbouring island of Saint Kitts constitute the Saint Kitts and Nevis, Federation of Saint Kitts ...

), gill or ghyll, glen,

gorge A canyon (; archaic British English spelling: ''cañon''), gorge or chasm, is a deep cleft between escarpments or cliffs resulting from weathering and the erosion, erosive activity of a river over geologic time scales. Rivers have a natural tend ...

, kloof (

South Africa South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. Its Provinces of South Africa, nine provinces are bounded to the south by of coastline that stretches along the Atlantic O ...

), and chine (

Isle of Wight The Isle of Wight (Help:IPA/English, /waɪt/ Help:Pronunciation respelling key, ''WYTE'') is an island off the south coast of England which, together with its surrounding uninhabited islets and Skerry, skerries, is also a ceremonial county. T ...

) A ravine is generally a fluvial slope landform of relatively steep (cross-sectional) sides, on the order of twenty to seventy percent in gradient. Ravines may or may not have active streams flowing along the downslope channel which originally formed them; moreover, often they are characterized by intermittent streams, since their geographic scale may not be sufficiently large to support a perennial stream.

Definition

According to

Merriam-Webster Merriam-Webster, Incorporated is an list of companies of the United States by state, American company that publishes reference work, reference books and is mostly known for Webster's Dictionary, its dictionaries. It is the oldest dictionary pub ...

, a ravine is "a small, narrow, steep-sided valley that is larger than a gully and smaller than a canyon and that is usually worn by running water". Some societies and languages do not differentiate between a gully and ravine; in others, there is a distinction, particularly when concerning environmental management.

Formation

Gullies are often found in hilly or mountainous regions, where water runoff is guided downhill by steep slopes and over time erodes the landscape. A ravine is the final step in gully erosion, formed when a

has eroded so severely it forms a deep cut in the earth. A gully can be classified as a ravine after it reaches a large depth, typically in excess of .

Environmental impact

Ravine erosion contributes heavily to land loss globally and particularly threatens agricultural lands. Additionally, soil loss contributes to pollution, flooding, and

sedimentation Sedimentation is the deposition of sediments. It takes place when particles in suspension settle out of the fluid in which they are entrained and come to rest against a barrier. This is due to their motion through the fluid in response to th ...

of waterways. The formation of ravine lands can be sped up by

deforestation Deforestation or forest clearance is the removal and destruction of a forest or stand of trees from land that is then converted to non-forest use. Deforestation can involve conversion of forest land to farms, ranches, or urban use. Ab ...

and overgrazing. In Indian badlands, soil erosion is estimated to exceed a rate of annually.

Examples

Hawaii

The shield volcanoes of Hawaii have significant impact on the distribution of ravines across the islands, specifically Mauna Loa and Mauna Kea, the former of which is one the most active shield volcanoes on Earth. Both of these volcanoes show V-shaped ravines on their flanks, solely where they have been mantled by Pahala ash. Being the older of the two, Mauna Kea displays more pronounced dissection of these ravines. Rainfall and infiltration capacity are critical to valley initiation on the Hawaiian volcanoes. Once these valleys are initiated, their streams incise to form V-shaped ravines. Eventually, they become sufficiently deep ravine systems and expose groundwater activity. The deepest of these incisions are U-shaped, theatre-headed valleys.

Notable ravines

* Babi Yar, Ukraine * Bam Bam Amphitheaters, Gabon * Barranco de Badajoz, Spain * Barranco del Infierno, Spain * Gravina Ravine, Italy * Moola Chotok, Pakistan * Ravenna Park, United States * Rauðfeldsgjá, Iceland * Stuðlagil, Iceland * Taishaku Valley, Japan * Toronto ravine system, Canada

Definition

Formation

Environmental impact

Examples

Hawaii

Notable ravines

References

Citations

Bibliography

External links