scholarly journals Effect of hydraulic parameters on sediment transport capacity in overland flow over erodible beds

2011 ◽  
Vol 8 (4) ◽  
pp. 6939-6965 ◽  
Author(s):  
M. Ali ◽  
G. Sterk ◽  
M. Seeger ◽  
M. P. Boersema ◽  
P. Peters
Keyword(s):  
Shear Stress ◽  
Sediment Transport ◽  
Hydraulic Parameters ◽  
Transport Capacity ◽  
Slope Gradient ◽  
Mean Flow ◽  
Stream Power ◽  
Unit Discharge ◽  
Sediment Transport Capacity ◽  
Mean Flow Velocity

Abstract. Sediment transport is an important component of the soil erosion process, which depends on several hydraulic parameters like unit discharge, mean flow velocity, and slope gradient. In most of the previous studies, the impact of these hydraulic parameters on transport capacity was studied for non-erodible bed conditions. Hence, this study aimed to examine the influence of unit discharge, mean flow velocity and slope gradient on sediment transport capacity for erodible beds and also to investigate the relationship between transport capacity and composite force predictors i.e. shear stress, stream power, unit stream power and effective stream power. In order to accomplish the objectives, experiments were carried out using four well sorted sands (0.230, 0.536, 0.719, 1.022 mm). Unit discharges ranging from 0.07 to 2.07 × 10−3 m2 s−1 were simulated inside the flume at four slopes (5.2, 8.7, 13.2 and 17.6 %) to analyze their impact on sediment transport rate. The sediment transport rate measured at the bottom end of the flume by taking water and sediment samples was considered equal to sediment transport capacity, because the selected flume length of 3.0 m was found sufficient to reach the transport capacity. The experimental result reveals that the slope gradient has a stronger impact on transport capacity than unit discharge and mean flow velocity due to the fact that the tangential component of gravity force increases with slope gradient. Our results show that unit stream power is an optimal composite force predictor for estimating transport capacity. Stream power and effective stream power can also be successfully related to the transport capacity, however the relations are strongly dependent on grain size. Shear stress showed poor performance, because part of shear stress is dissipated by bed irregularities, bed form evolution and sediment detachment. An empirical transport capacity equation was derived, which illustrates that transport capacity can be predicted from median grain size, total discharge and slope gradient.

scholarly journals Effect of hydraulic parameters on sediment transport capacity in overland flow over erodible beds

2012 ◽  
Vol 16 (2) ◽  
pp. 591-601 ◽  
Author(s):  
M. Ali ◽  
G. Sterk ◽  
M. Seeger ◽  
M. Boersema ◽  
P. Peters
Keyword(s):  
Shear Stress ◽  
Sediment Transport ◽  
Hydraulic Parameters ◽  
Transport Capacity ◽  
Slope Gradient ◽  
Mean Flow ◽  
Stream Power ◽  
Unit Discharge ◽  
Sediment Transport Capacity ◽  
Mean Flow Velocity

Abstract. Sediment transport is an important component of the soil erosion process, which depends on several hydraulic parameters like unit discharge, mean flow velocity, and slope gradient. In most of the previous studies, the impact of these hydraulic parameters on transport capacity was studied for non-erodible bed conditions. Hence, this study aimed to examine the influence of unit discharge, mean flow velocity and slope gradient on sediment transport capacity for erodible beds and also to investigate the relationship between transport capacity and composite force predictors, i.e. shear stress, stream power, unit stream power and effective stream power. In order to accomplish the objectives, experiments were carried out in a 3.0 m long and 0.5 m wide flume using four well sorted sands (0.230, 0.536, 0.719, 1.022 mm). Unit discharges ranging from 0.07 to 2.07 × 10−3 m2 s−1 were simulated inside the flume at four slopes (5.2, 8.7, 13.2 and 17.6%) to analyze their impact on sediment transport rate. The sediment transport rate measured at the bottom end of the flume by taking water and sediment samples was considered equal to sediment transport capacity, because the selected flume length of 3.0 m was found sufficient to reach the transport capacity. The experimental result reveals that the slope gradient has a stronger impact on transport capacity than unit discharge and mean flow velocity due to the fact that the tangential component of gravity force increases with slope gradient. Our results show that unit stream power is an optimal composite force predictor for estimating transport capacity. Stream power and effective stream power can also be successfully related to the transport capacity, however the relations are strongly dependent on grain size. Shear stress showed poor performance, because part of shear stress is dissipated by bed irregularities, bed form evolution and sediment detachment. An empirical transport capacity equation was derived, which illustrates that transport capacity can be predicted from median grain size, total discharge and slope gradient.

scholarly journals Investigating Behavior of Six Methods for Sediment Transport Capacity Estimation of Spatial-Temporal Soil Erosion

Water ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3054
Author(s):  
Linh Nguyen Van ◽  
Xuan-Hien Le ◽  
Giang V. Nguyen ◽  
Minho Yeon ◽  
Sungho Jung ◽  
...  
Keyword(s):  
Sediment Transport ◽  
Soil Erosion ◽  
Sediment Concentration ◽  
Sediment Runoff ◽  
Additional Parameter ◽  
Transport Capacity ◽  
Stream Power ◽  
Sediment Transport Capacity ◽  
Wide Range ◽  
Depth Analysis

Estimation of sediment transport capacity (STC) plays a crucial role in simulating soil erosion using any physics-based models. In this research, we aim to investigate the pros and cons of six popular STC methods (namely, Shear velocity, Kilinc-Richardson (KR), Effective stream power, Slope and unit discharge, Englund-Hansen (EH), and Unit stream power) for soil erosion/deposition simulation at watershed scales. An in-depth analysis was performed using the selected STC methods integrated into the Grid Surface Subsurface Hydrologic Analysis model for investigating the changes in morphology at spatial-temporal scales at the Cheoncheon watershed, South Korea, over three storm events. Conclusions were drawn as follows. (1) Due to the ability of the KR and EH methods to include an additional parameter (i.e., erodibility coefficient), they outperformed others by producing more accurate simulation results of sediment concentration predictions. The KR method also proved to be superior to the EH method when it showed a more suitable for sediment concentration simulations with a wide range of sediment size and forcing magnitude. (2) We further selected 2 STC methods among the 6 methods to deeply explore the spatial distribution of erosion/deposition. The overall results were more agreeable. For instance, the phenomenon of erosion mainly occurred upstream of watersheds with steep slopes and unbalanced initial sediment concentrations, whereas deposition typically appeared at locations with flat terrain (or along the mainstream). The EH method demonstrated the influence of topography (e.g., gradient slope) on accretionary erosion/deposition results more significantly than the KR method. The obtained results contribute a new understanding of rainfall-sediment-runoff processes and provide fundamental plans for soil conservation in watersheds.

scholarly journals Prediction of sediment transport capacity based on slope gradients and flow discharge

PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0256827
Author(s):  
Kai Zhang ◽  
Wang Xuan ◽  
Bai Yikui ◽  
Xu Xiuquan
Keyword(s):  
Sediment Transport ◽  
Overland Flow ◽  
Soil Slope ◽  
Transport Capacity ◽  
Slope Gradient ◽  
Particle Size Range ◽  
Flow Discharge ◽  
Brown Soil ◽  
Sediment Transport Capacity ◽  
Model Slope

Sediment transport capacity (Tc) is an essential parameter in the establishment of the slope soil erosion model. Slope type is an important crucial factor affecting sediment transport capacity of overland flow, and vegetation can effectively inhibit soil loss. Two new formulae of sediment transport capacity (Tc) are proposed of brown soil slope and vegetation slope in this study and evaluate the influence of slope gradient (S) and flow discharge (Q) on sediment transport capacity of different slope types. Laboratory experiments conducted using four flow discharges (0.35, 0.45, 0.55, and 0.65 L s-1), four slope gradients (3, 6, 9, and 12°), and two kinds of underlying surface (Brown soil slope, Vegetation slope). The soil particle size range is 0.05–0.5mm. The vegetation stems were 2mm in diameter and randomly arranged. The results show that the sediment transport capacity was positively correlated with the flow discharge and slope gradient. The vegetation slope’s average sediment transport capacity is 11.80% higher than the brown soil slope that same discharge and slope gradient conditions. The sensitivity of sediment transport capacity to flow discharge on brown soil slope is higher than that of slope gradient. The sensitivity of sediment transport capacity of vegetation slope to slope gradient is more heightened than flow discharge. The sediment transport capacity was well predicted by discharge and slope gradient on brown soil slope (R2 = 0.982) and vegetation slope (R2 = 0.993). This method is helpful to promote the study of the sediment transport process on overland flow.

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