scholarly journals Interrill erosion, runoff and sediment size distribution as affected by slope steepness and antecedent moisture content

2010 ◽  
Vol 7 (4) ◽  
pp. 6447-6489 ◽  
Author(s):  
M. B. Defersha ◽  
S. Quraishi ◽  
A. Melesse
Keyword(s):  
Soil Erosion ◽  
Size Distribution ◽  
Sediment Yield ◽  
Rainfall Intensity ◽  
Black Soil ◽  
Slope Steepness ◽  
Sediment Size ◽  
Antecedent Moisture ◽  
Runoff Rate ◽  
Antecedent Moisture Content

Abstract. Soil erosion is a two-phase process consisting of the detachment of individual particles and their transport by erosive agents such as flowing water. The rate at which erosion occurs depends upon the individual as well as interactive effects of different parameters responsible for soil erosion. The study discusses results of a laboratory analysis and evaluates the effect of slope steepness and antecedent moisture content on sediment yield (wash) and runoff rate. Interrill sediment yield, splash detachment, runoff, and sediment size distribution were measured in laboratory erosion pans under simulated total duration of 90 min. Rainfall intensity at 120 mm/hr, 70 mm/hr, and 55 mm/hr were applied sequentially at 9, 25, and 45% slope steepness for three soils (Alemaya Black soil, Regosols, and Cambisols) varied from clay to sandy clay loam in texture with wet and dry antecedent water contents. As slope steepness increased from 9 to 25% splash increased for five treatments and decreased for the remaining treatment; washed sediment increased for all treatments. As slope increased from 25 to 45% splash decreased for five treatments but increased for one treatment, and washed sediment increased for three treatments but decreased for the other three treatments. Pre-wetting decreased splash detachment for all soil treatments and rate of reduction was high for the highly aggregated soil, Alemaya Black soil and low for the less aggregated soil Regosols. Splash sediment and sediment yield was not correlated. Change in splash with increase in slope steepness was also not correlated with change in sediment yield. Change in runoff rate with increase in slope steepness was correlated (r=0.66) with change in sediment yield. For Alemaya Black soil and Regosols, splashed sediment size distribution was correlated with washed sediment size distribution. Interrill erosion models that include runoff and rainfall intensity parameters were a better fit for these data than the rainfall intensity based model. The exponent term, b, values in (E=a Ib) model did not approach 2.00 for all treatments. For the same slope steepness factor, both rainfall and rainfall-runoff based models provided different erodibility coefficients at different levels of slope and moisture contents.

scholarly journals The effect of slope steepness and antecedent moisture content on interrill erosion, runoff and sediment size distribution in the highlands of Ethiopia

2011 ◽  
Vol 15 (7) ◽  
pp. 2367-2375 ◽  
Author(s):  
M. B. Defersha ◽  
S. Quraishi ◽  
A. Melesse
Keyword(s):  
Sediment Yield ◽  
Rainfall Intensity ◽  
Black Soil ◽  
Flowing Water ◽  
Two Phase ◽  
Splash Erosion ◽  
Moisture Contents ◽  
Sediment Size ◽  
Antecedent Moisture ◽  
Interrill Erosion

Abstract. Soil erosion is a two-phase process consisting of the detachment of individual particles and their transport by the flowing water. This study discusses the results of laboratory experiments in which for three soils, the runoff depth, sediment yield, splash erosion and sediment size were measured. Rainfall intensity, slope and antecedent moisture contents were varied in the experiment. The soil types ranged from clay to sandy clay loam (Alemaya Black soil, Regosols and Cambisols). Rainfall was applied for six sequential 15-min periods with rainfall intensities varying between 55 and 120 mm h−1. The three slopes tested were 9, 25, and 45 %. Results show that as slope increased from 9 to 25 %, splash erosion and sediment yield increased. An increase in slope from 25 to 45 % generally decreases in splash erosion. Sediment yield for one soil increased and one soil decreased with slope and for the third soil the trend was different between the two initial moisture contents. Sediment yield was correlated (r = 0.66) with runoff amounts but not with splash erosion. Interrill erosion models that were based on the flowing water and rainfall intensity fitted the data better than when based on rainfall intensity solely. Models that assume a positive linear relationship between erosion and slope may overestimate sediment yield.

Characteristics of soil erosion and sediment size distribution for different land uses in the Chinese Mollisol region

2021 ◽  
Vol 18 (5) ◽  
pp. 1295-1306
Author(s):  
Hai-ou Shen ◽  
Jun Feng ◽  
Dong-li Wang ◽  
Hong-li Li ◽  
Yu Wang
Keyword(s):  
Soil Erosion ◽  
Size Distribution ◽  
Land Uses ◽  
Sediment Size

Effects of vegetation cover on sediment particle size distribution and transport processes in natural rainfall conditions on post-fire hillslope plots in South Korea

Soil Research ◽  
2016 ◽  
Vol 54 (8) ◽  
pp. 937 ◽  
Author(s):  
Ewane Basil Ewane ◽  
Heon-Ho Lee
Keyword(s):  
Particle Size ◽  
Size Distribution ◽  
Vegetation Cover ◽  
Rainfall Intensity ◽  
Transport Processes ◽  
Vegetation Recovery ◽  
Particle Sizes ◽  
Sediment Size ◽  
Aggregate Breakdown ◽  
Soil Burn Severity

Sediments were collected from four slow vegetation recovery plots, six fast vegetation recovery plots and five unburned plots at a post-fire site on a rainfall event basis and sorted for size distribution. The aim was to evaluate the effects of vegetation cover, soil aggregate stability, slope and rainfall intensity on sediment size distribution, transport selectivity and erosion processes between the burned and unburned treatment plots. Sediment detachment and transport mechanisms and the particle size transport selectivity of the eroded sediment were assessed based on enrichment ratios (ER) and mean weighted diameter (MWD) methods. The most eroded particle size class in all treatment plots was the 125–250μm class and, generally, the percentage of eroded particle sizes did not increase with slope and rainfall intensity. Higher MWD of the eroded sediment was related to a higher percentage of bare soil exposed and gravel content associated with high soil burn severity and soil disaggregation in the slow vegetation recovery plots. The enrichment of finer clay silt particle sizes increased with varying maximum 30-min rainfall intensity (I30) in the slow vegetation recovery plots, and reflected increased aggregate breakdown and transport selectivity, whereas no good relationship was found in the fast vegetation recovery and unburned plots with varying I30. A minimum I30 of <3.56mmh–1 and a maximum of 10.9mmh–1 were found to be the threshold rainfall intensity values necessary for aggregate breakdown and transport of finer particles by both rainsplash and rainflow in the slow vegetation recovery plots, whereas the response was weak in the fast vegetation recovery and unburned plots following varying I30 dominated only by rainsplash transport closer to the plot sediment collector. The results show that higher vegetation cover in the fast vegetation recovery and unburned plots reduces erosive rainfall energy by 5.6- and 17.7-fold respectively, and runoff energy by 6.3- and 21.3-fold respectively, limiting aggregate breakdown and transport selectivity of finer particles compared with the slow vegetation recovery plots.

scholarly journals Hydraulic characteristics and sediment generation on slope erosion in the Three Gorges Reservoir Area, China

2016 ◽  
Vol 64 (3) ◽  
pp. 237-245 ◽  
Author(s):  
Feng Qian ◽  
Dongbin Cheng ◽  
Wenfeng Ding ◽  
Jiesheng Huang ◽  
Jingjun Liu
Keyword(s):  
Soil Erosion ◽  
Sediment Yield ◽  
Rainfall Intensity ◽  
Purple Soil ◽  
Three Gorges ◽  
Slope Gradient ◽  
Stream Power ◽  
Yield Rate ◽  
The Three Gorges ◽  
Subsurface Runoff

Abstract Hydrological processes play important roles in soil erosion processes of the hillslopes. This study was conducted to investigate the hydrological processes and the associated erosional responses on the purple soil slope. Based on a comprehensive survey of the Wangjiaqiao watershed in the Three Gorges Reservoir, four typical slope gradients (5°, 10°, 15°and 20°) were applied to five rainfall intensities (0.6, 1.1, 1.61, 2.12 and 2.54 mm·min-1). The results showed that both surface and subsurface runoff varied greatly depending on the rainfall intensity and slope gradient. Surface runoff volume was 48.1 to 280.1 times of that for subsurface runoff. The critical slope gradient was about 10°. The sediment yield rate increased with increases in both rainfall intensity and slope gradient, while the effect of rainfall intensity on the sediment yield rate was greater than slope gradient. There was a good linear relationship between sediment yield rate and Reynolds numbers, flow velocity and stream power, while Froude numbers, Darcy-Weisbach and Manning friction coefficients were not good hydraulic indicators of the sediment yield rate of purple soil erosion. Among the three good indicators (Re, v and w), stream power was the best predictor of sediment yield rate (R2 = 0.884). Finally, based on the power regression relationship between sediment yield rate, runoff rate, slope gradient and rainfall intensity, an erosion model was proposed to predict the purple soil erosion (R2 = 0.897). The results can help us to understand the relationship between flow hydraulics and sediment generation of slope erosion and offer useful data for the building of erosion model in purple soil.

Soil Erosion Process in Sloped Shrub Plots under Simulated Rainfall

2011 ◽  
Vol 347-353 ◽  
pp. 2094-2097 ◽  
Author(s):  
Pei Qing Xiao ◽  
Wen Yi Yao ◽  
Chang Gao Wang
Keyword(s):  
Soil Erosion ◽  
Sediment Yield ◽  
Rainfall Intensity ◽  
Infiltration Rate ◽  
Simulated Rainfall ◽  
Slope Gradient ◽  
Erosion Process ◽  
Infiltration Process ◽  
Negative Relation ◽  
Runoff And Sediment Yield

Runoff, sediment yield and infiltration process of shrub plots were studied under rainfall intensities of 45, 87 and 127 mm/h with 20° slope gradient using simulated rainfall experiment. The results showed that cumulative runoff and cumulative sediment yield of shrub plot had an obvious positive correlation with rainfall time. Under rainfall intensity of 45 mm/h, runoff and sediment yield of shrub plot kept a constant level. Under rainfall intensity of 87 mm/h, runoff kept a fluctuant increase, whereas sediment yield basically kept steady. Under rainfall intensity of 127 mm/h, runoff and sediment yield of shrub plot increased evidently due to the formation of erosion pits. Infiltration rate of shrub plot had a negative relation with runoff as well as sediment yield.

Evaluation of the CREAMS model. I. Sensitivity analysis of the soil erosion sedimentation component for aggregated clay soils

Soil Research ◽  
1989 ◽  
Vol 27 (3) ◽  
pp. 545 ◽  
Author(s):  
DM Silburn ◽  
RJ Loch
Keyword(s):  
Soil Erosion ◽  
Sediment Yield ◽  
Overland Flow ◽  
Clay Soils ◽  
Slope Length ◽  
Sediment Size ◽  
Total Runoff ◽  
Peak Runoff ◽  
Relative Change ◽  
Parameter Values

The sensitivity of the soil erosion component of the CREAMS model to changes in various input parameters was assessed in the range of parameter values suited to erosion from aggregated clay soils. Predictions of total sediment yield were sensitive to changes in a number of parameters, and interactions between parameter values were observed, e.g., for situations when either detachment of sediment or transport capacity of overland flow limited sediment yield. The CREAMS model was classified as: (i) sensitive to: specific gravity of sediment (Sgi), slope steepness; (ii) sensitive under some conditions, moderately sensitive under others to: total runoff (Vu); Universal Soil Loss Equation factors of erodibility (K), cover (C) and support practices (P); Manning-type available shear parameter (nbov); (iii) moderately sensitive to: peak runoff rate (�p), storm erosivity (EI30), slope length, sediment size distribution and kinematic viscosity. The model was judged to be 'sensitive' to a parameter when change in that parameter caused an equal or greater relative change in predicted sediment yield.

scholarly journals Assessment of marl properties effect on sediment and runoff rate at different rainfall intensity under field rainfall simulator

2009 ◽  
Vol 89 (4) ◽  
pp. 85-94
Author(s):  
S.H. Hosseini ◽  
S. Feiznia ◽  
H.R. Peyrovan
Keyword(s):  
Analysis Of Variance ◽  
Sediment Yield ◽  
Rainfall Intensity ◽  
Chemical Properties ◽  
The Other ◽  
Physical And Chemical Properties ◽  
Rainfall Simulator ◽  
Runoff Rate ◽  
Physical And Chemical ◽  
And Chemical Properties

The objective of this study is to assess the effect of physical and chemical properties of Marl's formations on sediment and runoff rates at different rainfall intensities, based on using field rainfall simulator. For this purpose, first Marl's formations (Neocene's units) were separated to five units including Halite siltstone(NgSiH), Siltstone (NgSi), Mudstone (gy1C), Gypsum mudstone (gy1CG) and Halite clay stone (gy2CH), based on physical and chemical properties. Then runoff and sediment rates were determined in each unit at two intensities (30 and 60 mm/h) using rainfall simulator. Analysis of variance and Duncan's tests showed that Halite siltstone unit has produced the highest amount of runoff and sediment rates and then the runoff and sediment rates of other subunits in decreasing order are as follows: Siltstone, gy2CH, gylCG and gy1C are 5% significant level. The trend of induced runoff and sediment rates at different times showed that in Halite siltstone and Siltstone units the runoff amounts were fixed rapidly at 2nd ten minutes. And, on the other units, the runoff amounts were fixed at 3rd ten minutes and sediment yield was increased rapidly at 3rd ten minutes.

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