Medium-term evolution of a gully developed in a loess-derived soil

Nachtergaele, Jeroen; Poesen, Jean; Wijdenes, D Oostwoud; Vandekerckhove, Liesbeth

doi:10.1016/s0169-555x(02)00075-2

Cited by 82 publications

(64 citation statements)

References 14 publications

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“…usually attributed to decreasing catchment area and decreasing stream power (Nachtergaele et al, 2002). In the study area, the decrease of gully volume expansion rate ( Figure 5) since around 1995 is attributed to relatively high rainfall (which reduced runoff response due to higher biomass availability and decreased pressure on the land), less interannual rain variability and increased implementation of SWC techniques in the gullies and in the catchment during these years (Nyssen et al, 2006c).…”

Section: Natural Versus Anthropogenic Processesmentioning

confidence: 86%

Dynamics of soil erosion rates and controlling factors in the Northern Ethiopian Highlands – towards a sediment budget

Nyssen

Poesen

Moeyersons

et al. 2007

Earth Surf Processes Landf

132

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This paper analyses the factors that control rates and extent of soil erosion processes in the 199 ha May Zegzeg catchment near Hagere Selam in the Tigray Highlands (Northern Ethiopia). This catchment, characterized by high elevations (2100–2650 m a.s.l.) and a subhorizontal structural relief, is typical for the Northern Ethiopian Highlands. Soil loss rates due to various erosion processes, as well as sediment yield rates and rates of sediment deposition within the catchment (essentially induced by recent soil conservation activities), were measured using a range of geomorphological methods. The area‐weighted average rate of soil erosion by water in the catchment, measured over four years (1998–2001), is 14·8 t ha−1 y−1, which accounts for 98% of the change in potential energy of the landscape. Considering these soil loss rates by water, 28% is due to gully erosion. Other geomorphic processes, such as tillage erosion and rock fragment displacement by gravity and livestock trampling, are also important, either within certain land units, or for their impact on agricultural productivity. Estimated mean sediment deposition rate within the catchment equals 9·2 t ha−1 y−1. Calculated sediment yield (5·6 t ha−1 y−1) is similar to sediment yield measured in nearby catchments. Seventy‐four percent of total soil loss by sheet and rill erosion is trapped in exclosures and behind stone bunds. The anthropogenic factor is dominant in controlling present‐day erosion processes in the Northern Ethiopian Highlands. Human activities have led to an overall increase in erosion process intensities, but, through targeted interventions, rural society is now well on the way to control and reverse the degradation processes, as can be demonstrated through the sediment budget. Copyright © 2007 John Wiley & Sons, Ltd.

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Section: Natural Versus Anthropogenic Processesmentioning

confidence: 86%

Dynamics of soil erosion rates and controlling factors in the Northern Ethiopian Highlands – towards a sediment budget

Nyssen

Poesen

Moeyersons

et al. 2007

Earth Surf Processes Landf

132

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“…Other site-specific explanations include the consequence of a decrease in the local slope gradient during headcut retreat, the increase of soil and water conservation practices through time and land abandonment. Laboratory (Kosov et al, 1978) and field studies (Oostwoud Wijdenes and Bryan, 2001;Nachtergaele et al, 2002; have confirmed this negative exponential growth. As is apparent in Fig.…”

Section: Gully Headcut Retreat Rates In Ethiopia Compared To Other Sementioning

confidence: 86%

Gully head retreat rates in the semi-arid highlands of Northern Ethiopia

Frankl¹,

Poesen²,

Deckers³

et al. 2012

Geomorphology

160

120

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Due to overgrazing and agricultural intensification, gully erosion severely affects sub-Saharan countries; however, insufficient quantitative studies exist for this part of the world. This paper presents data on gully head retreat rates in Northern Ethiopia and relates these rates to gully and environmental characteristics. The monitoring of headcuts over one rainy season (2010) revealed that present-day retreat rates are low, with average annual linear (R l ), areal (R a ) and using archival terrestrial (and aerial) photographs, headcut retreat rates proved to be significantly higher than those in the short-term. The averages for R l , R a and V e are 3.8 m y -1 , 31.5 m² y -1 and 47.7 m³ y -1 , respectively. Retreat rates are up to 10 times higher after road construction. On the medium-to long-term time scale, headcut retreat rates were positively related to the catchment area (A). A power relationship that best describes the relation between V e and A is V e = 0.

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“…La naturaleza cíclica de los procesos de acarcavamiento, es de sobra conocida (Bradford y Piest, 1980). De manera que el volumen de una cárcava puede decrecer a partir de un determinado momento, relacionándose este hecho con dinámicas de sedimentación y revegetación del cauce (Nachtergaele et al, 2002).…”

Section: Discussionunclassified