Gully 439282 222664752 2008-06-30T14:35:13Z Iridescent 937705 Cleanup/[[WP:AWB/T|typo fixing]], typos fixed: the the → the using [[Project:AutoWikiBrowser|AWB]] :''This article refers to the landform. For other uses, see [[Gully (disambiguation)]].'' [[Image:Gully ElPasoCounty CO USA.jpg|thumb|left|300px|Gully in [[El Paso County, Colorado|El Paso County]], [[Colorado]], [[USA]].]] [[Image:Gully in the Kharkov region.jpg|thumb|200px|Gully in [[Kharkiv oblast]], [[Ukraine]].]] A '''gully''' is a [[landform]] created by running [[water]] [[erosion|eroding]] sharply into [[soil]], typically on a [[hill]]side. Gullies resemble large [[ditches]] or small [[valleys]], but are [[metre]]s to tens of metres in depth and width. When the gully formation is in process, the [[volumetric flow rate|water flow rate]] can be substantial, which causes the significant deep cutting action into soil. '''Gullying''', or '''gully erosion''', is the process by which gullies are formed. Hillsides are more prone to gullying when they are cleared of vegetation, through [[deforestation]], [[over-grazing]] or other means. The eroded [[soil]] is easily carried by the flowing water after being dislodged from the ground, normally when [[rainfall]] falls during short, intense storms such as during [[thunderstorms]]. Gullies reduce the productivity of [[Farmland (farming)|farmland]] where they incise into the land, and produce [[sediment]] that may clog downstream [[waterbodies]]. Because of this, much effort is invested into the study of gullies within the scope of [[geomorphology]], in the prevention of gully erosion, and in restoration of gullied landscapes. The total soil loss from gully formation and subsequent downstream [[river]] [[sedimentation]] can be sizable. ==Hydraulic mining== [[Image:Panorámica de Las Médulas.jpg|thumb|right|250px|Panoramic view of Las Médulas]] Artificial gullies are formed during [[hydraulic mining]] when jets or steams of water are projected onto soft [[alluvial deposits]] to extract [[gold]] or [[tin ore]]. The remains of such mining methods are very visible landform features in old [[goldfield]]s such as in [[California]] and northern [[Spain]]. The [[badland]]s at [[Las Medulas]] for example, were created during the Roman period by [[hushing]] or [[hydraulic mining]] of the gold-rich alluvium with water supplied by numerous aqueducts tapping nearby rivers. Each [[aqueduct]] produced large gullies below by erosion of the soft deposits. The effluvium was carefully washed with smaller streams of water to extract the [[nugget]]s and gold dust. ==Etymology== The earliest usage of the term is from [[1657]]. It originates from the [[French language|French]] word ''goulet'', a diminutive form of ''goule'' which means ''throat''. It is possible that the term was derived from a type of [[knife]] at the time, a ''gully-knife'', because hills that have gullies look as if they are cut open with a sharp knife. ==See also== {{Commonscat}} * [[Arroyo (creek)]] * [[Canyon]] * [[Gulch]] * [[Ravine]] * [[Wadi]] * [[Lavaka]] * [[Badlands]] ==References== * ''Oxford English Dictionary'' [[Category:Environmental soil science]] [[Category:Slope landforms]] [[Category:Fluvial landforms]] [[ca:Barranc]] [[cv:Çырма]] [[es:Barranco (geografía)]] [[fr:Ravine]] [[he:ערוץ]] [[ja:ガリ (地形)]] [[pl:wąwóz]] [[ru:Овраг]]