Analysis of factors determining sediment yield variability in the highlands of northern Ethiopia

Tamene, Lulseged; Park, S.J.; Dikau, Richard; Vlek, Paul L. G.

doi:10.1016/j.geomorph.2005.10.007

Cited by 156 publications

(125 citation statements)

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“…The SSY rates vary between 150 and 2680 t km -2 year -1 , with an average of 1228 t km -2 year -1 . The latter is slightly higher than the African average, estimated at about 1000 t km -2 year -1 (Tamene, 2006). The disparity between the various values quoted above reflects both the difficulty of measuring mechanical erosion and fluvial suspended sediment transport, and the spatial variability of erosion intensity in response to the harsh and aggressive climate, the poorly vegetated soils and the marked relief.…”

Section: Sediment Yieldmentioning

confidence: 86%

“…As for the overall slope index, it integrates the high elevation difference of the catchments considered. Other studies have used elevation difference or average catchment slope instead of G i to characterize topography (Tamene, 2006;Haregeweyn, 2008). Finally, runoff depth, R d , describes the runoff patterns of the studied watersheds, which depend intrinsically on vegetation cover, soil permeability, slope and the nature of the drainage network.…”

Section: Sediment Yield Variability In Central Tunisiamentioning

confidence: 99%

“…This usually results in correlating sedimentation rates and their associated water erosion with easily available geomorphologic, hydrological, physiographic and climatic parameters. Factors used to describe erosion and sedimentation in most models are land use, watershed average slope, precipitation, runoff shear stress, soil cohesion and surface roughness (Tamene, 2006;Grausso et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

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Sediment yield variability in central Tunisia: a quantitative analysis of its controlling factors

Ayadi

Abida

Djebbar

et al. 2010

Hydrological Sciences Journal

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This paper refers to the quantification and prediction of the sedimentation rate of 26 hillside-dam reservoirs in Central Tunisia. The objectives of the study are to develop a simple and practical methodology to identify controlling factors of sedimentation, and to propose a regionalization from the study sites. Principal component analysis (PCA) and complementary multi-dimensional statistical methods are used to relate highly variable area-specific sediment yield to hydro-morphometric, lithological, geomorphological and anthropogenic characteristics of catchments. It appears that catchment area is not the main controlling factor of sedimentation in the studied area. The overall slope index, drainage network characteristics and runoff parameters are also important in characterizing sediment yield. Applied to the annual sedimentation rate series, PCA resulted in retaining the first three principal axes, explaining 65% of the total variance. Statistical methods showed that the overall slope index, the total drainage length, the compacity index and the runoff parameters are as important for the sedimentation quantification. This allowed a graphical clustering of the study zone into three distinct groups having similar behaviours: (i) watersheds characterized by high sediment transport rates and high runoff coefficients, (ii) basins distinguished by relatively low values of both flow discharge and sediment transport rates, and (iii) watersheds with an intermediate sediment yield, especially characterized by relatively high relief. In a second step, a multiple regression model including the four characteristic catchment properties was developed, presenting a valuable tool to predict area-specific sediment yield from catchments in central Tunisia. This model shows reasonable efficiency with an absolute prediction error of 81%.Key words reservoir sedimentation; hillside reservoir; central Tunisia; principal component analysis; stepwise regression Variabilité de l'exportation sédimentaire en Tunisie Centrale: analyse quantitative des déterminants Résumé Cette étude s'intéresse à la quantification et à la prévision du taux d'envasement de 26 lacs collinaires situés en Tunisie Centrale. L'objectif de cette étude est de mettre au point une méthodologie simple et pratique pour chercher les facteurs explicatifs de l'envasement, et de procéder à une régionalisation sur les retenues des lacs collinaires étudiés. Une analyse en composantes principales ainsi que différents outils statistiques multivariés ont été utilisés pour identifier la grande variabilité du taux d'ablation en fonction des propriétés hydromorphométriques, lithologiques, géomorphologiques et anthropiques des bassins versants. Il s'avère que la surface de drainage n'est pas le facteur déterminant de l'envasement dans la zone d'étude. En fait, l'indice de pente global, les caractéristiques du réseau hydrographique ainsi que les paramètres de ruissellement sont aussi importants lors de la quantification de la sédimentation. Les trois premières composante...

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Section: Sediment Yieldmentioning

confidence: 86%

Section: Sediment Yield Variability In Central Tunisiamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Sediment yield variability in central Tunisia: a quantitative analysis of its controlling factors

Ayadi

Abida

Djebbar

et al. 2010

Hydrological Sciences Journal

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“…Soil and water conservation measures were implemented largely in the drought-affected areas of the country [7]. The interventions were focused on both mechanical and biological measures [8,9].…”

Section: Introduction Backgroundmentioning

confidence: 99%

Sustainability of Climate Resilient Soil and Water Conservation Strategies Nexus the Practices in Tragedy at the Upper Blue Nile Basin of Northwestern Ethiopia: Economic Welfare Implication to the Farming Communities

At¹,

Gm²,

Dagmawi³

et al. 2017

J Earth Sci Clim Change

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The existing unplanned and intensive agricultural practices are sustained at the expense of our endangered natural resources and future generations advantages seem highly compromised. The study was carried out in Northwestern Ethiopia at the Northwestern basin of the Blue Nile, the lower belt of Mount Choke where intensive but traditional farming system is predominant. The study evaluated climate smart soil and water conservation practices, compared the effectiveness of climate resilience strategies across variable farming systems and attributed reasons why sustaining soil and water conservation structures is a tragedy for the farming communities. Formal interview schedule, biophysical data, key informants and focus group discussions were used to gather primary data. The collected data was analyzed employing the Tobit Econometric Model using STATA. The result indicated that the variables like size of land holding (5%), slope (1%), presence of rodents on SWC structures (5%), frequency of extension contact (1%) and training opportunity significantly influenced the longevity of climate smart SWC structures. Farmers in all observed watersheds were found to involve climate smart SWC strategies, usually by mass campaign. However, sustainability of the already made structures is unsecured and get destroyed in less than a year (a tragedy in the area), except in locations with interventions of NGO-supported projects where zero grazing is adopted. In terms of the existing advantages, biological conservation measures (plantation on ridges) were found to be the most effective and sustainable) followed by level Fanyajuu (especially in area closures). On the other hand, soil bund terraces were found to be the least sustainable. Better conservation and maintained structures were observed in highland watersheds than lowlands. Total avoidance of free grazing, public awareness regarding ecological sustainability and setting social bylaws can lead climate resilience and ecological conservation. In addition, creation of public awareness on ecological sustainability can prolong longevity of climate smart SWC structures which can in turn help farmers improve economic welfare.

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“…Despite the fact that soil erosion can be caused by geomorphologic process, accelerated soil erosion is principally favored by human activities. Rapid population growth, deforestation, un-suitable land cultivation, uncontrolled and overgrazing have resulted in accelerated soil erosion in the world principally in developing countries like Ethiopia (Adebe and Sewnet, 2014; Tamene et al, 2006). All reservoirs formed by dams on natural rivers are subject to some degree of sediment inflow and deposition.…”

Section: Introductionmentioning

confidence: 99%

Sedimentation Study in a Reservoir Using Remote Sensing Technique

Merina¹

2016

Appl Ecol Env Res

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Abstract.Reservoir sedimentation is a severe problem faced by dams caused due to soil erosion which is almost immeasurable at source and occurs in the catchment areas of the reservoirs. The present study describes the evaluation of sedimentation carried out for Vaigai reservoir situated in Tamil Nadu, India. Vaigai reservoir nourishes the inhabitants through water storage and supply for irrigation and water power. Nowadays, capacity loss occurs in the reservoir due to sedimentation. As it is highly tedious and uneconomical to do hydrographic surveys, the frequentness in finding the sediment yield becomes impossible. But the recent application of remote sensing and GIS technologies in the field of Civil Engineering make it possible. The Satellite Remote Sensing (SRS) method for prediction of reservoir sedimentation uses directly the water-spread area of the reservoir at a particular elevation on the date of pass of the satellite. With known area and the difference in level of water, the capacity and thereby the loss in capacity of the reservoir due to sedimentation can also be estimated. This paper illustrates the prediction of sedimentation at Vaigai reservoir using remote sensing and ArcGIS.

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Analysis of factors determining sediment yield variability in the highlands of northern Ethiopia

Cited by 156 publications

References 43 publications

Sediment yield variability in central Tunisia: a quantitative analysis of its controlling factors

Sediment yield variability in central Tunisia: a quantitative analysis of its controlling factors

Sustainability of Climate Resilient Soil and Water Conservation Strategies Nexus the Practices in Tragedy at the Upper Blue Nile Basin of Northwestern Ethiopia: Economic Welfare Implication to the Farming Communities

Sedimentation Study in a Reservoir Using Remote Sensing Technique

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