:''This article refers to the landform. For other uses, see
Gully (disambiguation).''
A 'gully' is a
landform created by running
water eroding sharply into
soil, typically on a
hillside. Gullies resemble large
ditches or small
valleys, but are
metres to tens of metres in depth and width. When the gully formation is in process, the
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 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.
Etymology
The earliest usage of the term is from
1657. It originates from the
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
★
Arroyo (creek)
★
Canyon
★
Gulch
★
Ravine
★
Wadi
References
★ ''Oxford English Dictionary''