scholarly journals Investigating transport capacity equations in sediment yield modelling for the Cariri semi-arid region of Paraiba-PB/Brazil

2015 ◽  
Vol 367 ◽  
pp. 374-381
Author(s):  
E. E. De Figueiredo ◽  
C. C. R. A. Souto ◽  
Z. C. Vieira
Keyword(s):  
Sediment Transport ◽  
Soil Erosion ◽  
The State ◽  
Transport Capacity ◽  
Stream Power ◽  
Study Region ◽  
Physically Based Model ◽  
Sediment Size ◽  
Physically Based ◽  
Semi Arid

Abstract. In the semi arid Cariri region of the state of Paraiba, Brazil, runoff is of the Hortonian type generated by excess of rainfall over infiltration capacity, and soil erosion is governed by rainfall intensity and sediment size. However, the governing sediment transport mechanism is not well understood. Sediment transport generally depends on the load of sediment provided by soil erosion and on the transport capacity of the flow. The latter is mainly governed by mechanisms such as water shear stress, or stream power. Accordingly, the load of sediment transported by the flow may vary depending on the mechanism involved in the equation of estimation. Investigation of the sediment transport capacity of the flow via a distributed physically-based model is an important and necessary task, but quite rare in semi-arid climates, and particularly in the Cariri region of the state of Paraíba/Brazil. In this study, the equations of Yalin, Engelund & Hansen, Laursen, DuBoys and Bagnold have been coupled with the MOSEE distributed physically based model aiming at identifying the mechanisms leading to the best model simulations when compared with data observed at various basin scales and land uses in the study region. The results obtained with the investigated methods were quite similar and satisfactory suggesting the feasibility of the mechanisms involved, but the observed values were better represented with Bagnold’s equation, which is physically grounded on the stream power, and we recommend it for simulations of similar climate, runoff generation mechanisms and sediment characteristics as in the study region.

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 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.

Application of Erosion 2D Model for Erosion Studies in Makurdi Metropolis of Benue State, Nigeria

2011 ◽  
Vol 367 ◽  
pp. 815-825 ◽  
Author(s):  
M.O. Isikwue ◽  
T.G. Amile
Keyword(s):  
Soil Erosion ◽  
Soil Loss ◽  
Loss Rate ◽  
Physically Based Model ◽  
Cover Cropping ◽  
Physically Based ◽  
The City ◽  
Land Grading ◽  
2D Model ◽  
Soil Loss Rate

The equations of Erosion 2D Model (a physically based model) were transformed into a computer programme called EROSOFT and used to predict the rate of soil loss in Makurdi metropolis. The model has detachment, transport and deposition components. Four sites were chosen within the metropolis for this study. Soil samples were collected from the sites for laboratory analysis. Rainfall and runoff fluids were collected from the sites to determine their densities. Levelling instrument was used to detremine the channels slopes. The model predicted an average annual soil loss rate of 310kg m-2s-1 for the metropolis. The sensitivity analysis of the model indicates that straight slopes are more prone to soil erosion. The result of the model deviates slightly from established facts that, sandy soils are more erodible and hence prone to be easily detached. Nevertheless, the model shows that soil erosion is influenced by slope geometry and rainfall intensity. The study attributes the major causes of soil erosion in the city to urban runoff concentration and removal of vegetation, and therefore suggests the use of land grading, land forming and cover cropping as well as conservation structures like road side drains for the control of erosion in the metropolis.

scholarly journals Modelling Hydrological Processes and Identifying Soil Erosion Sources in a Tropical Catchment of the Great Barrier Reef Using SWAT

Water ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2179
Author(s):  
Vahid Rafiei ◽  
Afshin Ghahramani ◽  
Duc-Anh An-Vo ◽  
Shahbaz Mushtaq
Keyword(s):  
Sediment Transport ◽  
Soil Erosion ◽  
Water Balance ◽  
Great Barrier Reef ◽  
Hydrological Processes ◽  
Barrier Reef ◽  
Water Balance Components ◽  
Study Region ◽  
Erosion Hotspots ◽  
The Impact

Study region: North Johnstone catchment, located in the north east of Australia. The catchment has wet tropical climate conditions and is one of the major sediment contributors to the Great Barrier Reef. Study focus: The purpose of this paper was to identify soil erosion hotspots through simulating hydrological processes, soil erosion and sediment transport using the Soil and Water Assessment Tool (SWAT). In particular, we focused on predictive uncertainty in the model evaluations and presentations—a major knowledge gap for hydrology and soil erosion modelling in the context of Great Barrier Reef catchments. We carried out calibration and validation along with uncertainty analysis for streamflow and sediment at catchment and sub-catchment scales and investigated details of water balance components, the impact of slope steepness and spatio-temporal variations on soil erosion. The model performance in simulating actual evapotranspiration was compared with those of the Australian Landscape Water Balance (AWRA-L) model to increase our confidence in simulating water balance components. New hydrological insights for the region: The spatial locations of soil erosion hotspots were identified and their responses to different climatic conditions were quantified. Furthermore, a set of land use scenarios were designed to evaluate the effect of reforestation on sediment transport. We anticipate that protecting high steep slopes areas, which cover a relatively small proportion of the catchment (4–9%), can annually reduce 15–26% sediment loads to the Great Barrier Reef.

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.

The role of the geometry and frequency of rectangular rills in the relationship between sediment concentration and stream power

Soil Research ◽  
1997 ◽  
Vol 35 (6) ◽  
pp. 1359 ◽  
Author(s):  
B. Fentie ◽  
C. W. Rose ◽  
K. J. Coughlan ◽  
C. A. A. Ciesiolka
Keyword(s):  
Soil Erosion ◽  
Overland Flow ◽  
Sediment Concentration ◽  
Stream Power ◽  
Flume Experiments ◽  
Erosion Processes ◽  
Physically Based ◽  
The Relationship ◽  
Raindrop Impact

We examined, both experimentally and theoretically, whether rilling results in higher soil erosion than would have occurred without rilling. The possibility of rilling occurs when overland flow-driven erosion processes are dominant over erosion due to raindrop impact, and that is the situation assumed in this paper. Stream power (or a quantity related to stream power such as shear stress) is commonly used to describe the driving variable in flow-driven erosion. Five flume experiments were designed to investigate the relationship between stream power and sediment concentration and how this relationship is affected by the ratio of width to depth of flow (r), and the frequency or number of rills per metre width (N) of rectangular rills. This paper presents the results of these experiments and uses a physically based soil erosion theory to show that the results of the 5 flume experiments are in accord with this theory. This theory is used to investigate the effect of all possible rectangular rill geometries and frequencies on the maximum possible sediment concentration, i.e. the sediment concentration at the transport limit, by developing general relationships for the influence of r and N on sediment concentration. It is shown that increased stream power, which can be due to rilling, does not necessarily result in higher sediment concentration.

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