Assessment of gully erosion rates through interviews and measurements: a case study from northern Ethiopia

2006 ◽  
Vol 31 (2) ◽  
pp. 167-185 ◽  
Author(s):  
Jan Nyssen ◽  
Jean Poesen ◽  
Maude Veyret-Picot ◽  
Jan Moeyersons ◽  
Mitiku Haile ◽  
...  
Keyword(s):  
Gully Erosion ◽  
Northern Ethiopia ◽  
Erosion Rates

Assessment of gully erosion using conventional field measurements: A case study from northern Ethiopia

2016 ◽  
Vol 71 (6) ◽  
pp. 134A-139A ◽  
Author(s):  
A. Klik ◽  
F. Kluibenschadl ◽  
S. Strohmeier ◽  
F. Ziadat ◽  
C. Zucca
Keyword(s):  
Field Measurements ◽  
Gully Erosion ◽  
Northern Ethiopia ◽  
Conventional Field

scholarly journals MATLAB Virtual Toolbox for Retrospective Rockfall Source Detection and Volume Estimation Using 3D Point Clouds: A Case Study of a Subalpine Molasse Cliff

Geosciences ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 75
Author(s):  
Dario Carrea ◽  
Antonio Abellan ◽  
Marc-Henri Derron ◽  
Neal Gauvin ◽  
Michel Jaboyedoff
Keyword(s):  
Point Cloud ◽  
Natural Hazard ◽  
Point Clouds ◽  
Volume Estimation ◽  
Natural Phenomena ◽  
Frequency Distributions ◽  
Erosion Rates ◽  
3D Point Clouds

The use of 3D point clouds to improve the understanding of natural phenomena is currently applied in natural hazard investigations, including the quantification of rockfall activity. However, 3D point cloud treatment is typically accomplished using nondedicated (and not optimal) software. To fill this gap, we present an open-source, specific rockfall package in an object-oriented toolbox developed in the MATLAB® environment. The proposed package offers a complete and semiautomatic 3D solution that spans from extraction to identification and volume estimations of rockfall sources using state-of-the-art methods and newly implemented algorithms. To illustrate the capabilities of this package, we acquired a series of high-quality point clouds in a pilot study area referred to as the La Cornalle cliff (West Switzerland), obtained robust volume estimations at different volumetric scales, and derived rockfall magnitude–frequency distributions, which assisted in the assessment of rockfall activity and long-term erosion rates. An outcome of the case study shows the influence of the volume computation on the magnitude–frequency distribution and ensuing erosion process interpretation.

The Rural-Urban Dichotomy in the Developing World: A Case Study from Northern Ethiopia

1988 ◽  
Vol 78 (3) ◽  
pp. 337
Author(s):  
Assefa Mehretu ◽  
Jonathan Baker
Keyword(s):  
Developing World ◽  
Northern Ethiopia

scholarly journals Surface and subsurface flow effect on permanent gully formation and upland erosion near Lake Tana in the northern highlands of Ethiopia

2010 ◽  
Vol 14 (11) ◽  
pp. 2207-2217 ◽  
Author(s):  
T. Y. Tebebu ◽  
A. Z. Abiy ◽  
A. D. Zegeye ◽  
H. E. Dahlke ◽  
Z. M. Easton ◽  
...  
Keyword(s):  
Water Table ◽  
Gully Erosion ◽  
Grazing Land ◽  
Cross Sectional ◽  
Lake Tana ◽  
Erosion Rates ◽  
Remotely Sensed Imagery ◽  
Reservoir Siltation ◽  
Upland Erosion ◽  
Elevated Water

Abstract. Gully formation in the Ethiopian Highlands has been identified as a major source of sediment in water bodies, and results in sever land degradation. Loss of soil from gully erosion reduces agricultural productivity and grazing land availability, and is one of the major causes of reservoir siltation in the Nile Basin. This study was conducted in the 523 ha Debre-Mawi watershed south of Bahir Dar, Ethiopia, where gullies are actively forming in the landscape. Historic gully development in a section of the Debre-Mawi watershed was estimated with semi structured farmer interviews, remotely sensed imagery, and measurements of current gully volumes. Gully formation was assessed by instrumenting the gully and surrounding area to measure water table levels and soil physical properties. Gully formation began in the late 1980's following the removal of indigenous vegetation, leading to an increase in surface and subsurface runoff from the hillsides. A comparison of the gully area, estimated from a 0.58 m resolution QuickBird image, with the current gully area mapped with a GPS, indicated that the total eroded area of the gully increased from 0.65 ha in 2005 to 1.0 ha in 2007 and 1.43 ha in 2008. The gully erosion rate, calculated from cross-sectional transect measurements, between 2007 and 2008 was 530 t ha−1 yr−1 in the 17.4 ha area contributing to the gully, equivalent to over 4 cm soil loss over the contributing area. As a comparison, we also measured rill and interrill erosion rates in a nearby section of the watershed, gully erosion rates were approximately 20 times the measured rill and interrill rates. Depths to the water table measured with piezometers showed that in the actively eroding sections of the gully the water table was above the gully bottom and, in stable gully sections the water table was below the gully bottom during the rainy season. The elevated water table appears to facilitate the slumping of gully walls, which causes the gully to widen and to migrate up the hillside.

scholarly journals The Exclusive Nature of Inclusive Productive Employment in the Rural Areas of Northern Ethiopia

2017 ◽  
Vol 32 (6) ◽  
pp. 1044-1060 ◽  
Author(s):  
Crelis F Rammelt ◽  
Maggi Leung ◽  
Kebede Manjur Gebru
Keyword(s):  
Rural Areas ◽  
Development Policy ◽  
Northern Ethiopia ◽  
Structured Interviews ◽  
Sociology Of Work ◽  
Poverty Threshold ◽  
Self Reliance ◽  
Shed Light ◽  
Productive Employment

Inclusiveness, with its emphasis on productive employment, has become central in development policy. From this perspective, unwaged-work is condemned for not being sufficiently productive; that is, for failing to lift incomes above a poverty threshold. However, insights from the sociology of work reveal a range of unwaged activities that are potentially highly productive in their contribution to self-reliance. The article explores whether these activities are undermined by the promotion of inclusiveness. The case study takes place in Tigray, Ethiopia. Through semi-structured interviews, the activities of different households were classified according to a typology of work based on the work of Gorz, Illich, Wheelock, Taylor, Williams and others. Results show the heterogeneous character of work and shed light on the meaning of productivity. The article ends with a discussion on the risk that inclusiveness may be achieved by replacing activities ‘that count’ with activities ‘that can be counted’.

scholarly journals Characteristics and importance of rill and gully erosion: a case study in a small catchment of a marginal olive grove

2015 ◽  
Vol 41 (1) ◽  
pp. 107 ◽  
Author(s):  
E.V. Taguas ◽  
E. Guzmán ◽  
G. Guzmán ◽  
T. Vanwalleghem ◽  
J.A. Gómez
Keyword(s):  
Gully Erosion ◽  
Olive Grove ◽  
Small Catchment
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