Editing Gully (section)

== Formation and consequences ==
Gully erosion can progress through a variety and combination of processes. The erosion processes include incision and bank erosion by water flow, mass movement of saturated or unsaturated bank or wall material, groundwater seepage - sapping the overlying material, collapse of soil pipes or tunnels in dispersive soils, or a combination of these to a greater or lesser degree.  Hillsides are more prone to gully erosion when they are cleared of vegetation cover through [[deforestation]], [[over-grazing]], or other means. Gullies in rangelands can be initiated by concentrated water flow down tracks worn by livestock or vehicle tracks. The flowing water easily carries the eroded [[soil]] after being dislodged from the ground, typically when [[rainfall]] falls during short, intense storms such as [[thunderstorms]].

A gully may grow in length through [[Headward erosion|headward (i.e., upstream) erosion]] at a [[knick point]]. This erosion can result from [[interflow]] and soil piping ([[internal erosion]]) as well as [[surface runoff]]. Gully erosion may also advance laterally through similar methods, including mass movement, acting on the gully walls (banks), and the development of 'branches' (a type of [[tributary]]).

Gullies reduce the productivity of farmlands where they incise into the land and produce [[sediment]] that may choke downstream [[waterbodies]] and reduce water quality within the drainage system and lake or coastal system.  Because of this, much effort is invested into the study of gullies within the scope of [[geomorphology]] and [[soil science]], in the prevention of gully erosion, and [[soil science|the]]  in remediation and rehabilitation of gullied landscapes.  The total soil loss from gully formation and subsequent downstream [[river]] [[sedimentation]] can be substantial, especially from unstable soil materials prone to [[dispersion (soil)|dispersion]].

When water is directed over exposed ground, gully erosion removes soil near drainage lines. This may result in divided properties, loss of arable land, diminished amenities, and decreased property values. Additionally, it can lead to sedimentation, discoloration of the water supply, and creating a haven for rodents.<ref name=":0">{{Cite web |last=Department of Jobs |first=Precincts and Regions |date=2020-06-04 |title=Gully erosion - Agriculture |url=https://agriculture.vic.gov.au/farm-management/soil/erosion/gully-erosion |access-date=2023-10-22 |website=Agriculture Victoria |language=en-AU}}</ref>

Water rushing over exposed, naked soil creates gullies and ridges that erode rock and soil. When water rushes across exposed terrain, it erodes or pushes dirt away, creating rills. Gravity causes rift erosion on a downward slope, with steeper slopes generating greater water flow. Sandier terrains are more commonly affected by rills most prevalent during the rainier months. Gullies develop when a rill is neglected for an extended time, thickening and expanding as soil erosion persists.<ref>{{Cite journal |last1=Nosko |first1=Radovan |last2=Maliariková |first2=Marcela |last3=Brziak |first3=Adam |last4=Kubáň |first4=Martin |date=2019-09-01 |title=Formation of Gully Erosion in the Myjava Region |journal=Slovak Journal of Civil Engineering |language=en |volume=27 |issue=3 |pages=63–72 |doi=10.2478/sjce-2019-0023 |bibcode=2019SJCE...27c..63N |s2cid=203849080 |issn=1338-3973|doi-access=free }}</ref>

The factors influencing gully erosion were investigated in Zaria, Kaduna state, Nigeria, utilizing SRTM data, soil samples, rainfall data, and satellite imagery. The findings indicated that the factors that had the biggest effects on gully erosion were slope (56%) and rainfall (26%), land cover (12%), and soil (6%). The investigation concluded that each particular component significantly influenced soil loss.<ref>{{Cite web |title=Journal of Research in Forestry, Wildlife and Environment |url=https://www.ajol.info/index.php/jrfwe |access-date=2023-10-22 |website=www.ajol.info}}</ref>

=== Effects of gullies ===
The loss of fertile farmland due to gully erosion is a severe environmental problem that lowers crop quality and may cause famine and food shortages. It also causes the soil to lose organic content, which has an impact on plant viability. As items washed from fields end up in rivers, streams, or vacant land, erosion also contaminates the ecosystem. Because of increased population expansion and increasing land demand, erosion also threatens the natural ecosystem, encroaching on natural forests. Important assets including homes, power poles, and water pipelines may also be destroyed.<ref>{{Cite web |date=2020-04-29 |title=Gully Erosion, Definition, Causes, Effects And Prevention - Jotscroll |url=https://www.jotscroll.com/forums/3/posts/159/gully-erosion-definition-causes-effects-and-prevention.html |access-date=2023-10-23 |website=www.jotscroll.com |language=en-US}}</ref>

=== Prevention of gullies ===
Effective land management techniques can prevent gullies. These techniques include keeping vegetation along drainage lines, using more water, classifying drainage lines as distinct land classes, stabilizing erosion, preventing vermin, distributing runoff evenly, keeping soil organic matter levels high, and avoiding over-cultivation. These tactics guarantee uniform rates of penetration and robust plant coverage.<ref name=":0" />

One serious environmental problem endangering sustainable development is gully erosion. Gullying prevention and control methods are dispersed and lacking, and they have low success and efficacy rates.<ref>{{Cite journal |last1=Frankl |first1=Amaury |last2=Nyssen |first2=Jan |last3=Vanmaercke |first3=Matthias |last4=Poesen |first4=Jean |date=January 2021 |title=Gully prevention and control: Techniques, failures and effectiveness |url=https://onlinelibrary.wiley.com/doi/10.1002/esp.5033 |journal=Earth Surface Processes and Landforms |language=en |volume=46 |issue=1 |pages=220–238 |doi=10.1002/esp.5033 |bibcode=2021ESPL...46..220F |hdl=1854/LU-8684568 |s2cid=228807598 |issn=0197-9337|hdl-access=free }}</ref> This review attempts to make a valuable contribution to effective gully prevention and management techniques by combining information from previous research. It is possible to stop the creation of gullies by changing how land is used, conserving water and soil, or implementing specific actions in areas with concentrated flow.<ref>{{Cite web |date=2020-04-29 |title=Gully Erosion, Definition, Causes, Effects And Prevention - Jotscroll |url=https://www.jotscroll.com/forums/3/posts/159/gully-erosion-definition-causes-effects-and-prevention.html |access-date=2023-10-23 |website=www.jotscroll.com |language=en-US}}</ref> Plant leftovers and other vegetation barriers can prevent erosion, although their usefulness is limited. The biophysical environment, terrain, climate, and geomorphology are examples of external elements that affect gully prevention and control.<ref>{{Cite journal |last1=Frankl |first1=Amaury |last2=Nyssen |first2=Jan |last3=Vanmaercke |first3=Matthias |last4=Poesen |first4=Jean |date=January 2021 |title=Gully prevention and control: Techniques, failures and effectiveness |url=https://onlinelibrary.wiley.com/doi/10.1002/esp.5033 |journal=Earth Surface Processes and Landforms |language=en |volume=46 |issue=1 |pages=220–238 |doi=10.1002/esp.5033 |bibcode=2021ESPL...46..220F |hdl=1854/LU-8684568 |s2cid=228807598 |issn=0197-9337|hdl-access=free }}</ref>

==== Stabilising gullies ====

Stabilizing gullies entails altering water flow to lessen scouring, sediment buildup, and revegetation. Water can be securely moved from the natural level to the gully floor using a variety of structures, including drop structures, pipe structures, grass chutes, and rock chutes. Structural modifications can be required along steep gully floors. Vegetation can reestablish itself thanks to sediments deposited over flatter gradients. Until the restoration is finished, damaged areas should be walled off.<ref>{{Cite web |last=Department of Jobs |first=Precincts and Regions |date=2020-06-04 |title=Gully erosion - Agriculture |url=https://agriculture.vic.gov.au/farm-management/soil/erosion/gully-erosion |access-date=2023-10-23 |website=Agriculture Victoria |language=en-AU}}</ref>

==== Gully remediation in Eastern Nigeria ====
Eastern Nigeria's people and ecology are seriously threatened by gully erosion. A research project focused on 370 families and nine risk regions evaluated the region's gully erosion issues.<ref>{{Cite journal |last1=Shit |first1=Pravat Kumar |last2=Paira |first2=Rumpa |last3=Bhunia |first3=GouriSankar |last4=Maiti |first4=Ramkrishna |date=2015-05-13 |title=Modeling of potential gully erosion hazard using geo-spatial technology at Garbheta block, West Bengal in India |journal=Modeling Earth Systems and Environment |language=en |volume=1 |issue=1–2 |pages=2 |doi=10.1007/s40808-015-0001-x |bibcode=2015MESE....1....2S |s2cid=130635566 |issn=2363-6211|doi-access=free }}</ref> The greatest perceived problem, according to the results, was biodiversity loss. In contrast, damage to properties, roads, and walkways was ranked as the least important issue. This implies a notable variation in the average evaluations across impacted individuals, underscoring the necessity for long-term repair approaches. Reducing soil loss, raising public knowledge of environmental issues, passing environmental legislation, and giving residents funds to strengthen their coping mechanisms are all advised by the study.<ref>{{Cite journal |last1=Igwe |first1=P. U. |last2=Ajadike |first2=J. C. |last3=Ogbu |first3=S. O. |date=2023-07-05 |title=Assessment of Gully Erosion Problems for its Remediation in Eastern Nigeria |url=https://cepajournal.com/index.php/jems/article/view/117 |journal=Journal of Environmental Management and Safety |language=en |volume=14 |issue=2 |pages=17 |issn=2141-1824}}</ref>

In Agulu-Nanka, Southeast Nigeria, a study examined the geoenvironmental causes driving gully erosion. It focuses on catchment management for gully erosion and geotechnical analysis.<ref>{{Cite journal |last=Nwankwoala |first=Hycienth O |date=2019-05-28 |title=Gully Erosion and Landslides in Southeastern Nigeria: Causes, Consequences and Control Measures |url=https://irispublishers.com/gjes/fulltext/gully-erosion-and-landslides-in-southeastern-nigeria-causes-consequences-and-control-measures.ID.000541.php |journal=Global Journal of Engineering Sciences |volume=2 |issue=4 |doi=10.33552/GJES.2019.02.000541|s2cid=198419282 |doi-access=free }}</ref> Through fieldwork, data was gathered utilizing GIS and GPS methods. According to the study, gully erosion occurs throughout, with Nanka/Oko having the highest concentration. The gully characteristic map shows variations in length and depth, emphasizing the necessity of considering gully vulnerability and giving erosion hazards immediate attention.<ref>{{Cite web |url=https://bibliotekanauki.pl/articles/1031662 |access-date=2023-10-23 |website=bibliotekanauki.pl}}</ref>