Introduction gullies can be prevented by such measures as increasing the absorptive. However, experi mental studies on gully erosion commonly lacked the ampleness of those dedicated to surface sheet erosion. The rill and gully system has fundamentally altered the hydrology of the upper watersheds, greatly decreasing time to peak runoff and significantly increasing stormflow. Ppt gully control measures powerpoint presentation. Does vegetation cover suppose gully erosion stabilization. Heede, research forester introduction the control of gullies is an important step in watershed rehabilitation. To check whether the erosion is active, look at the gully head, walls and floor. Rill erosion begins when a small stream forms during heavy rain. Gully erosion is best characterised as a bed instability that subsequently causes in bank instabilities. Investigating the causes and impacts of gully erosion in. Rill erosion can be reduced by reducing the volume and speed of surface water with grassed waterways and filter strips, ripped mulch lines, and contour drains.
Ephemeral gullies, ephemeral gully erosion, field measurements, rainfall, gis. Erosion caused by concentrated flow begins where overland flow converges to channelized flow conditions. Long and short term erosion rates were estimated using agertim assessment of gully erosion rates through interviews and measurements. Most types of gullies occur in romania, but the majority are relatively small, discontinuous, valleyside gullies. Contrary to sheet and rill erosion, the damage done to land by gully erosion is permanent. Technical supplement 14p gullies and their control ts14pii 210vineh, august 2007 figures figure ts14p1 leeds, sc. The nsw department of primary industries provides further detail on the treatment of gully erosion. Commonly speaking, soil erosion generally refers to detachment and transportation of soil and soil material from the place of origin by water, wind, ice or gravity and deposition to another place. Protecting the soil from runoff stops potential land degradation and assists with water quality protection. Each type is associated with the progressive concentration of runoff water as it moves downstream. Gully predictive models were trained in both the catchments and submitted to internal in the calibration catchment and external in the adjacent one validation, using samples extracted both from all cells of the catchments and only from cells located along flow concentration axes. The rate of gully erosion depends primarily on the runoff producing characteristics of the watershed, the watershed area, soil characteristics, sizeshape and slope of gully etc.
Assess the impact of the gully erosion on the various land uses in the study area between 2006 and 2012, the study covers part of auchi where the gully erosion has devastated a large area of land. The concrete dams built at several locations to check the erosion by the colonial office in 1945 could not withstand the weathesing effects of the slightly acidic groundwater and were weakened and destroyed. Gully erosion susceptibility mapping using artificial intelligence and. One fact is clear from the several studies and from a close field inspection of the affected areas. The gully floor can deepen until rock is exposed or the grade becomes flat enough.
Controls on gully formation following forest clearing in a. However, gully is visually the most impressive of all types of erosion elswaify, 1990. Evaluation of gully erosion contribution to total erosion. Repair work done in the early stages of newly formed gullies is easier.
Gully erosion is considered to be one of the main causes of land degradation in arid and. Assessment of treatment options soil is a resource best used insitu, not in transit. Assessment of gully erosion process dynamics for water resources management 189 for integrated water resources management, knowledge of soil erosion processes active within the landscape is of fundamental importance. Gully form of soil erosion causes extensive socioeconomic and. Assessment of gully erosion process dynamics for water. Gully erosion article about gully erosion by the free. Lukes hospital gully erosion site, uyo lga, akwa ibom state final report i abbreviated resettlement action plan arap for st lukes hospital gully erosion site, uyo l. Although the quantities of material re moved from these gullies was loosely correlated. Gully erosion is where runoff cuts into the land surface to a depth of 0. The splash effect also increases compaction and destroys open soils structure.
Effects of gully erosion control on sediment stabilization and erosion. General definition gully treatment is the stabilization of active gullies by vegetative or structural measures or a combination thereof. The motive of this study is to combine the rbf method with ica and compare it. Soil erosion sheet, rill and wind erosion detachment and transportation of soil particles caused by rainfall runoffsplash, irrigation runoff, or wind that degrades soil quality. Koestnerc, ausda forest service, rocky mountain research station, 2500 pine knoll drive, flagstaff, arizona 86001 barizona geological survey, 416 congress street, suite 100, tucson, arizona 85701 cusda forest service, rocky mountain research station, tonto national forest. Towards an assessment of the ephemeral gully erosion. Gully erosion mapping is a crucial step to monitor the erosion process and to study its current and future local impacts. The region is the grain production and ecological security base of china where the fertile and productive mollisols are distributed.
Other interesting aspects of gully erosion in these drainageways are 9. Classic gully calculating gully erosion the soil loss from concentrated flow, gullies, and other similar types of erosion will be determined by calculating the volume of soil removed from the eroded area. Once a gully is formed erosion can continue in three ways. Soil infiltration rates were also measured using single ring infiltrometer. The first is that present control measures are not entirely satisfactory in particular, a more detailed understanding of the mechanisms of different kinds of gullies is needed so that treatments can be designed to suit. Dsl1, permanent vegetative establishment grass seeding assistance is authorized for lime and fertilizer, eligible seed, seeding operation and seedbed prep. Precipitates of iron sulphide, gypsum and sulphur are widespread. Their implications for gully erosion modelling are presented along with some recommendations for future research. To model the gesm, 12 affecting factors on gully erosion were identified. The most obvious mechanism is spalling, by which faleks of material peel off the wall and drop. Gullies are too large to be repaired with normal tillage equipment and will require special treatment for stabilization. Unlike sheet an d rill erosion, which occurs as a result of the impact of raindrops and water flowing on the. Gully erosion gullies are channels deeper than 30cm that cannot. Gully erosion in the agulunanka region of anambra state.
Monitoring and estimating ephemeral gully erosion using field. An erosion gully site in ankpa the ankpa metropolis and environs is one of the areas of southeastern nigeria that have been ravaged by severe gully erosion. In this study the environmental impacts of the gully erosion were investigated and remedies are being suggested to arrest andor minimize the menace. Gully erosion definition is soil erosion produced by running water. Soil erosion soil erosion is the loosening and displacement of topsoil from the land due to the action of agents like wind and water. Gully erosion is the removal of soil along drainage lines by surface water runoff. Keywords gully, erosion, classification, morphology, development, models.
Chapter gully erosion and its control chapter gully erosion and its control gullying occurs in many parts of queensland. Repair work done in the early stages of newly formed gullies is easier and more economical than letting the. Gullies are an important part of the soil erosion process and their occurrence and development may cause serious problems to a regions economy. As a result, the gully is effectively shallower so that it may be filled or shaped at a later date graham, 1984, depending on pretreatment dimensions. Gully erosion, however, can also occur within a watercourse, typically within the upper reaches, and typically resulting from an active headcut migrating rapidly up the valley. Theyll give your presentations a professional, memorable appearance the kind of sophisticated look that todays audiences expect. Conventional tillage or the notill method may be used for.
The quantity of gully material removed during a given runoff event is a function of event size and prior storm occurrence. Extensive rill systems now occupy steep slopes previously covered with a deep litter horizon. Design of gully controls should draw on our understanding of these aspects. Severe gully erosion is a safety hazard and a major limitation to potential productive land use. Gully erosion as an important sediment source, conveyance of flow and sediment from upstream to downstream channel networks and contamination of water bodies by transported sediment and chemicals. Wind or water erosion is the physical wearing of the earths surface. Rill erosion is often described as the intermediate stage between sheet erosion and gully erosion. Commonly speaking, soil erosion generally refers to detachment and transportation of soil and soil material from the place of origin by water, wind, ice. Pdf gullies are an important part of the soil erosion process and.
Erosion is not always readily visible, even when soil loss exceeds unsustainable. Soil erosion is perhaps the most serious mechanism of land degradation in the tropics elswaify, et al. Worlds best powerpoint templates crystalgraphics offers more powerpoint templates than anyone else in the world, with over 4 million to choose from. In general, this type of gully can be crossed with farm equipment and obliterated with tillage. Gully erosion represents a major sediment source, although gully channels often occupy \5 % of the area of a catchment. Sustainability free fulltext gully erosion control. Gully erosion erosion soil and water farm management. Ephemeral gully erosion was very prominent in the study areas, and conservation practices need to be implemented to reduce this type of erosion. Through water erosion, approximately 400 thousand gully erosion formations were formed, covering over 500 thousand hectares according to g. Once started, gullies will continue to move by headward erosion or by slumping of the side walls unless steps are taken to stabilise the disturbance. Sheet, rill and gully erosion is the unwanted removal of soil from the land surface or through incised channels by the action of rainfall and runoff. Hessel and van asch 2003 studied the process of erosion in a small semiarid catchment of 3. Hillsides are more prone to gully erosion when they are cleared of vegetation, through deforestation, overgrazing or other means. An ephemeral gully typically erodes to the tilled depth.
Several discontinuous gullies developing on a hillside can merge and. Gully erosion, the most impressive and striking erosion type, has been recognized as one of the major global environmental problems. Many states in nigeria are currently under the threats of this phenomenal process, southeastern part of the country being the most affected. Pdf in this study, shortterm gully retreat was monitored from the active gullies selected in representative black soil area, using differential gps find, read. Ephemeral and classic gully erosionworksheet forms of erosion by water include sheet and rill, ephemeral gully, classic gully and stream bank. In this article, the gully erosion susceptibility map gesm was developed. Fullen2 wojciech zglobicki3 jean poesen4 the authors 2015. The development of gullies increases runoff and sediment connectivity in the landscape, hence increasing the risk of flooding and reservoir sedimentation verstraeten. The tons of soil loss can then be determined by multiplying the volume removed by the unit weight of the soil. Soil properties, which can vary significantly at different elevations down the soil profile, can be a major factor in the choice of treatment option, as well as how that treatment option is detailed.
Chapter gully erosion and its control publications. Gully erosion is the removal of soil from the surface and subsurface creating permanent channels greater than 30 centimetres 1 foot deep. This article is published with open access at gully erosion is an important environmental threat throughout the world and affects multiple soil and land functions. Gully erosion is a key process of land degradation and desertification posing. From the pgis studies, the main drivers of gully erosion were identified as an increase in bare land and agricultural land, and a reduction in grassland, meaning the hand of man is at work in suswa, so and we should not. Gully erosion is more difficult and expensive to control than sheet and rill erosion. Erosion is one of the surface processes that sculpture the earths landscape and constitutes one of the global environmental problems. Though the region was agriculturally developed relatively recently, it went through high intensity cultivation and fast succession processes within shorttime scales.
Pdf the characteristics of gully erosion over rolling hilly black soil. Several important themes emerged that include the importance and impact of technology. Water running over a gully head and trickling back against the headwall causes some erosion by wetting the soil. Although tillage removes the visible erosion, tillage moves soil into the voided area and loosens soil material for the next rainfall event. From gully erosion estimating soil loss from gully erosion ephemeral or classic definitions ephemeral gully a shallow channel cut by concentrated runoff where soil loosened by mechanical operations is removed, generally between tillage operations. However, humaninduced gullying is a serious form of land degradation reducing soil fertility. Gully erosion is the process by which gullies are formed. Gully erosion is a global driver of soil and landscape degradation. Under natural conditions gullying is an important process of landscape evolution. While the tillage does fill in the gully, each time the gully washes out again, the soil is lost from the gully and from along the sides of the gully as that soil was used to repair the gully. Gully erosion definition of gully erosion by merriamwebster. Modeling the contribution of ephemeral gully erosion under. Student solutions manual for use with applied linear regression models. Gully erosion is regarded as an indicator of deserti.
Tillage destroys soil structure and reduces the residue cover, leaving the soil surface more prone to erosion and runoff. It is also more spectacular than the other forms of erosion. Watersheds deteriorate because of misuse of the land man made changes, short intensive rainstorms, prolonged rains of moderate intensity, and rapid snow melts. Despite the uncertainty associated with the use of a unique rate of gully erosion, our evaluation of the gully contribution to the catchment outlet sediment yield was very consistent with the results obtained from two previous studies that were conducted in the same catchment. Check whether the erosion is active gully erosion can look dramatic, but if the gully has stabilised it may be better to leave it alone. Combining field monitoring and aerial imagery to evaluate. Weathering and erosion lead to the simultaneous process of degradation and aggradation. A study of early gullycontrol structures in the colorado. Photo 1 urban gully erosion migrating along a constructed stormwater drain qld photo 2 rural gully erosion migrating through pastoral land sa. In pakistan, 75% of the country is affected by water and wind erosion and gully erosion affects 36% of the agricultural area of the country according to g. 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. Rill erosion is the removal of soil by concentrated water running through little streamlets, or headcuts.
Gully erosion as a natural and humaninduced hazard pdf. Gully erosion can be a stormwater problem, a soil problem, a vegetation problem, or any combination of these three issues. Gully erosion, a rill channel becomes broader and deeper. A study of early gully control structures in the colorado front range by burchard h. Future work in greece should combine the current, large scale. Gully types, modes and conditions of formation and common advance mechanism. Further information can be found in assessing agricultural land maschmedt 2002. Soil erosion in nature may be a slow process geological erosion or a fast process promoted by human activities like overgrazing, deforestation. Gully erosion pdf 330kb saving soil a landholders guide to preventing and. We combine these to assess the hazard of gully erosion following forest clearing, expressed in terms of the probability of daily rainfall that is capable of initiating. Geotechnical assessment of gully erosion at ankpa area, north. Gully erosion as a natural and humaninduced hazard ion ionita1 michael a. Gully control designed to fix valley bottoms at a certain base level stabilizes the valley floor through sediment accumulation in the gully channel. Particularly gully erosion contributes significantly to the total sediment yield of a catchment.
Gully erosion is the destructive and dramatic form of land degradation in northeast china. Pdf gully erosion mapping using objectbased and pixel. Gully erosion is a highly visible form of soil erosion that affects soil productivity. Gully erosion supplies 40% of the fine sediment exported into the gbr lagoon, from just 0. Winner of the standing ovation award for best powerpoint templates from presentations magazine. Gully erosion mapping through field work is difficult, timeconsuming, and. Effects of hillslope gully stabilization on erosion and sediment. Disturbing dispersive soils may reactivate the gully and cause more erosion. Assessment of environmental impacts and remedies for gully. Soil properties, which can vary significantly at different elevations down the soil profile, can be a major factor in the choice of treatment option, as well as. Gully erosion occurs primarily as a result of rain drop impact, washing away by running water. Classic gully a channel or miniature valley cut by concentrated runoff into the earth, but. Average gully width, depth and lengths were measured using measuring tape at the beginning and end of the rainy season. Small weirs also confine the velocity of gully flow and its capacity to transport sediment into short sections, so that the stabilized bed gradient can be revegetated crouch et al.
It occurs along drainage lines and in deep depositional soils. The following state costshare practices are designed to address this concern. Rill and gully formation following the 2010 schultz fire. Evaluating factors responsible for gully development at the. In this research, gully erosion susceptibility mapping was. Gully erosion occurs during intense rainfall on saturated soils or when rills merge together into larger channels fig. Gully erosion results not only from surface flow but also often from subsurface flow.