Papers Published in the International Journal of Sediment Research

Volume 38, No.1, 2023

Pages 1-151 (February 2023)

1. Effects of hooked-collar on the local scour around a lenticular bridge pier

Rashid Farooq, Amir Hossein Azimi, Muhammad Atiq Ur Rehman Tariq, Afzal Ahmed

2. Application of Hausdorff fractal derivative to the determination of the vertical sediment concentration distribution

Hong guang Sun, Shiqian Nie, Aaron I. Packman, Yong Zhang, Dong Chen, Chengpeng Lu, Chunmiao Zheng

3. Loess erosion change modeling during heavy rainfall

Hongwu Zhang, Guangquan Liu, Chensu Zhao, Luohao Zhang, Qiang Zhang, Heng Fu, Shuai Cao

4. Novel green technology for wastewater treatment: Geo-material/geopolymer applications for heavy metal removal from aquatic media

Nenad Grba, Andre Baldermann, Martin Dietzel

5. Erosion and runoff reduction potential of vetiver grass for hill slopes: A physical model study

Shamontee Aziz, Mohammad Shariful Islam

6. Smart Sediment Particle: A novel approach to investigating fluvial bed entrainment using instrumented sensors

Yushu Xie, Bruce W. Melville, Asaad Y. Shamseldin, Colin N. Whittaker, Yifan Yang

7. Experimental study of the settling of twin spherical particles released side by side: The impact of particle size, fluid viscosity, initial spacing, and particle density

Yang Xiao, Jieqing Liu, Pei Zhang, Jian Zhou , Dongfang Liang, Zhihao Wang, Taotao Zhang, Saiyu Yuan, Hongwu Tang

8. Measurements and estimation of flow velocity in mobile bed rills

Yunyun Ban

9. A comparison between artificial neural network algorithms and empirical equations applied to submerged weir scour evolution prediction

Dawei Guan, Jingang Liu, Yee-Meng Chiew, Jian-Hao Hong, Liang Cheng

10. Geobag stepped spillway for check dams: A pilot study

Shu Yu, Fan Yue, Qiang Zhang, Zuyu Chen, Penghai Yin, Jianwei Hao, Laizhang Zhang , Ludong Hao

11. Deep learning long short-term memory combined with discrete element method for porosity prediction in gravel-bed rivers

Duong Tran Anh, Ahad Hasan Tanim, Daniel Prakash Kushwaha, Quoc Bao Pham, Van Hieu Bui

12. Assessment of equilibrium pressure-flow scour depth using jet flow theory

Mostafa Koushki, Mohammad R. Chamani, Mohammad N. Moghim

1. Effects of hooked-collar on the local scour around a lenticular bridge pier

Rashid Farooq, Amir Hossein Azimi, Muhammad Atiq Ur Rehman Tariq, Afzal Ahmed

Pages 1-11 Download PDF

Abstract: This paper presents the results of comprehensive laboratory experiments to investigate the effects of hooked-collar on the scour development around a vertical pier with a lenticular cross section. The flow around the pier was uniform, steady, and under the clear-water condition. The axial scour profiles for cases without and with a lenticular hooked-collar were measured and the effects of hooked-collar dimensions and elevation from the bed were examined. To compute the efficiency of hooked-collar for scour prevention, the results of local scour for a bridge pier without a collar and a bridge pier with a plain collar, without a hooked wall, were used as benchmark data sets. A wide range of hooked-collar geometries such as the ratio of collar width to the pier width, W_{c}/W_{p}, ranging from 1.5 to 3.5, the ratio of hooked-collar wall height to the pier width, H_{c}/W_{p}, ranging from 0.15 to 0.6, and the ratio of collar elevation to the pier width, E_{c}/W_{p}, of ?0.5, 0, and 0.5 were tested. The experimental results indicated that the equilibrium scour depth decreased with the ratio of hooked-collar to the pier width when W_{c} is twice the pier width, W_{p}. For W_{c}/W_{p} >2, the scour depth was similar to the tests with an infinitely large pier width. In addition, the scour depth consistently reduced as the hooked-collar wall height, H_{c}, to the pier width, W_{p}, approached 0.3. The highest scour reduction efficiency was achieved when the hooked-collar being placed on the bed surface. Empirical models were developed for prediction of maximum scour depth near the lenticular bridge pier with a modified collar. The results showed that the volume of scour hole around a lenticular pier increased non-linearly with the maximum scour depth and it was independent of the hooked-collar geometry.

Keywords: Local scour; Erosion Collar; Hooked-collar; Lenticular pier; Scour counter measure; Steady flow

2. Application of Hausdorff fractal derivative to the determination of the vertical sediment concentration distribution

Hong guang Sun, Shiqian Nie, Aaron I. Packman, Yong Zhang, Dong Chen, Chengpeng Lu, Chunmiao Zheng

Pages 12-23 Download PDF

Abstract: The Rouse formula and its variants have been widely used to calculate the steady-state vertical concentration distribution for suspended sediment in steady sediment-laden flows, where the diffusive flux is assumed to be Fickian. Turbulent flow, however, exhibits fractal properties, leading to non-Fickian diffusive flux for sediment particles. To characterize non-Fickian dynamics of suspended sediment, the current study proposes a Hausdorff fractal derivative based advection-dispersion equation (HADE) model, where the Fickian diffusive flux in the Rouse model is replaced by a fractal derivative re-scaled using a constant diffusivity. The order of the Hausdorff fractal derivative is designed to characterize the influence of the multi-fractal turbulence structure on sediment diffusion. Applications show that the HADE model, with the analytical solution expressed using a stretched exponential function, can accurately describe the observed vertical concentration profiles for suspended sediment with different sizes. This improvement well captures the non-exponential decay of the vertical sediment concentration in turbulent flow. Further analyses of measured sediment concentration profiles reveal that the Hausdorff fractal order decreases with the Rouse parameter, which describes the stronger impact of turbulent flow and a more uniform sediment concentration profile for smaller particles. Model comparisons also show that the HADE model provides better performance in describing the sediment concentration profiles than the improved Rouse formula and the standard fractional derivative advection-dispersion equation (FADE), which either under- or over-estimates vertical displacement of sediment particles, likely due to coherent turbulent structures.

Keywords: Anomalous diffusion; Hausdorff fractal derivative; Vertical concentration distribution; Suspended sediment; Metric transform

3. Loess erosion change modeling during heavy rainfall

Hongwu Zhang, Guangquan Liu, Chensu Zhao, Luohao Zhang, Qiang Zhang, Heng Fu, Shuai Cao

Pages 24-32 Download PDF

Abstract: A typical gully sub-basin with a complex geomorphological form is used to do a model test of gravity erosion of loess by considering the sequence of slopes in a prototype gully creating a sequence of underlying surface forms in the upper reaches. The results show that the runoff from heavy rainfall is the main external force for the erosion of loess, and also is an important influencing factor to stimulate and intensify the development of gravity erosion. The soil structure and the height of the critical surface have a direct impact on the possibility of gravity erosion. Spatially, the upper section of the drainage channel mainly experiences undercutting and headcut erosion, the middle section mainly experiences lateral erosion and gravity erosion, and the lower section alternately experiences sedimentation or alluvial erosion. Rainfall splash erosion produces a large amount of sand to yield high concentration mud flows in the middle and lower sections of the channel. Because of the mud flows the flood flow is obviously larger than the runoff volume formed by rainfall in a small watershed. The flood formed by high-intensity rainfall brings a large amount of sediment into the downstream rivers along the channel, indicating that under the condition that high-intensity rainfall on the Loess Plateau, lots sediment will enter the Yellow River, and the erosion deformation occurs on all slopes. Further the steep slope drainage flow causes undercutting and lateral erosion, and the soil body moves down along the slope under the action of gravity. The gully in the middle section still experience sediment washing in both depth and width, and the downstream gully continues to experiences sedimentation due to the reduction of the gradient, reflecting the adaptive adjustment of water flow and the boundary. Headcut erosion occurred on almost all slopes during different periods of rainfall, while gravity erosion mostly occurred on steep slope sections during periods of high-intensity rainfall.

Keywords: Gravity erosion; Slope erosion; Erosion modeling; Heavy rainfall

4. Novel green technology for wastewater treatment: Geo-material/geopolymer applications for heavy metal removal from aquatic media

Nenad Grba, Andre Baldermann, Martin Dietzel

Pages 33-48 Download PDF

Abstract: The aim of this paper is to show the concise chemico-physical adsorbent performance of water purification systems utilizing geo- (e.g., allophane, clinoptilolite, and smectite) and bio-polymer materials (e.g., chitosan or cellulose nanocomposite materials) and to propose an optimal ground-water remediation technique. The performance of geo-materials is evaluated based on the individual sorption and immobilization capacities for various priority substances and pollutants (e.g., lead, zinc, cadmium, copper, arsenic, and others), their availability, and cost-efficient use. A systematic assessment of the sorption potential of geo-materials in comparison to other available sorbents used for the removal of harmful aqueous metal ions is made through a literature review. This paper introduces novel sustainable technologies based on natural and tailored silicate-polymerized substances (geo-materials and geopolymers), and highlights their applicability in the treatment of water and solid matter contaminated by heavy metal ions. The advantages of geo-materials and geopolymers over other commercially available sorbents used for heavy metal ion removal from solution are presented through a literature review. Benefits and current challenges of geo-materials and geopolymers applications in water processing technologies and in environmental remediation are discussed, with recognition of their performance, individual sorption and immobilization capacities, availability, and cost-efficient use. The applications described here comprise: (i) the removal of heavy metal ions from contaminated water using in-situ remediation strategies; (ii) heavy metal ion immobilization through co-precipitation with silicate binders in underground stabilization and waste solidification scenarios; and (iii) a proposal for a new geo-material/geopolymer-based solidification and stabilization technology for efficient, sustainable, and simultaneous treatment of soil/sediment and groundwater at environmental hotspots. Clay-substituted geopolymers, smectite, and zeolites are distinguished by their superb sorption and immobilization capacities for heavy metal ions, while biosorbents can play an important role in the removal of metals, metalloids (e.g., arsenic), and other contaminants. More research on individual removal mechanisms of heavy metals will provide new clues on the development of remediation strategies in advanced scientific and field applications, and on atomic-to-micron scale processes occurring at the solid–liquid interface.

Keywords: Geo-materials; Heavy metal ions; Environmental protection; Water treatment; Clay minerals; Sustainability

5. Erosion and runoff reduction potential of vetiver grass for hill slopes: A physical model study

Shamontee Aziz, Mohammad Shariful Islam

Pages 49-65 Download PDF

Abstract: Severe erosion is caused by intense rainfall in tropical regions. The erodible soil of steep hill slopes, accompanied by destruction of vegetation due to human interventions results in accelerated erosion. A sustainable and cost-effective solution such as vetiver grass (Chrysopogon zizanioides) is, thus, required to control the erosion process. In the current study, 6 small-scale glass models: 1 bare and 5 with vetiver grass, having a slope angle of 37 have been constructed. One year after planting, artificial rainfall of extremely high intensity was applied to all 6 small models and the role of vetiver canopy and roots in erosion and runoff control was observed. To see the effect of soil texture, one among these 5 models was made with silty sand and others contained sandy silt. The results demonstrated that, for sandy silt, the inclusion of vetiver reduced the soil loss by 94%-97%, and soil detachment rates were lowered by 95%. The average runoff also was reduced by 21%. The canopy cover showed a positive impact on reducing both quantities. An increase in average root diameter from 1.6 to 2.5 mm increases the soil loss due to its negative impact on added cohesion. The added cohesion showed a linearly negative correlation with soil loss. A composite system of vetiver and jute geotextile was most effective in erosion reduction among 4 vegetated models with sandy silt. Under same vetiver planting layout, the grass covered model of silty sand yielded 84% lower erosion and 62.5% lower runoff than the grass covered one with sandy silt. Thus, vetiver was more effective in erosion and runoff reduction for soil with a greater percentage of sand, and soil type dominated the erosion process.

Keywords: Erosion; Small-scale model experiments; Surface runoff; Artificial rainfall; Vetiver

6. Smart Sediment Particle: A novel approach to investigating fluvial bed entrainment using instrumented sensors

Yushu Xie, Bruce W. Melville, Asaad Y. Shamseldin, Colin N. Whittaker, Yifan Yang

Pages 66-82 Download PDF

Abstract: The Smart Sediment Particle (SSP) instrumented with multiple sensors to obtain tri-axial linear accelerations is used for studying the mechanism of coarse grain entrainment. Three bed arrangements are tested to examine their influences on entrainment processes and the threshold force and impulse conditions. The SSP shows satisfactory precision to capture the imperceptible movement tendencies immediately (e.g., 0.15 s) after the dislodgement. The experimental results show that bed packing can significantly affect the particle's entrainment threshold and the path of movement. Lateral movement is predominant for some cases because the entrainment path is based on the least work done by the flow, even if the direction is not aligned with the flow. The concept of effective protrusion height is proposed to quantify the effect of local bed arrangement on entrainment. The mean velocity field around the SSP is also measured together with the acceleration data. The mean threshold velocity and resultant impulse show consistent dependence on the bed arrangement. In general, the SSP shows a good prospect of being used to study small-scale entrainment mechanism.

Keywords: Smart Sediment Particle; Instrumented sensors; Entrainment behaviours; Tri-axial acceleration; Hydrodynamic force impulse

7. Experimental study of the settling of twin spherical particles released side by side: The impact of particle size, fluid viscosity, initial spacing, and particle density

Yang Xiao, Jieqing Liu, Pei Zhang, Jian Zhou , Dongfang Liang, Zhihao Wang, Taotao Zhang, Saiyu Yuan, Hongwu Tang

Pages 83-96 Download PDF

Abstract: The settling of solid particles in a fluid is an important process that needs to be considered in many fields of research. For example, the interactions among particles and between particles and the surrounding fluid are important topics in studying suspended sediment transport and water clarification. In this paper, the settling processes and interactions of twin spherical particles released side by side were experimentally studied. The Reynolds number varied in the range of 1-300, which is within the transition zone. Particle Tracking Velocimetry (PTV) and Particle Image Velocimetry (PIV) were utilized to capture the settlement trajectory, and provide insight into the flow fields around the particles. The influences of particle size, fluid viscosity, initial spacing, and particle density on the settling process were systematically investigated. The experimental results reveal that the initial spacing between the twin particles (l_{o}*) and the Reynolds number (Re) are the two most important factors affecting particle settling. The interaction between particles comprises only repulsion when the initial spacing is small, while the density of particles has little effect on the final settling state when the initial spacing is not very small. The flow fields around different particles are similar for the same Re, leading to similar final settlement behaviors, except for the case of l_{o}*= 0, when the influence of particle rotation cannot be ignored. Except for the case of l_{o}*= 0, although the particle density has little effect on the final settling behavior, it affects the repulsive process during settling. The final repulsive distance between the twin particles is highly dependent on Re and l_{o}*. Two critical Re values exist (~10 and ~100), where the repulsive distance is negatively correlated with Re when Re < 10, but it is positively correlated with Re when Re > 100. However, the repulsive distance is always negatively correlated with l_{o}*. These findings can improve understanding of more complex phenomena such as the particle group settling process and sediment transport.

Keywords: Particle settlement; Repulsion of particles; Particle tracking velocimetry (PTV); Particle image velocimetry (PIV); Particle density

8. Measurements and estimation of flow velocity in mobile bed rills

Yunyun Ban

Pages 97-104 Download PDF

Abstract: Rills are primary sediment sources and hillslope water/sediment runoff transport channels. Water flow velocities in rills are easily affected by bed condition over eroding and non-eroding slopes, which is an important hydrodynamic process in soil erosion research. This research is done to demonstrate the poorly understood “feedback mechanism” related to slope independence of flow velocity to slope gradient. A series of experiments were done on silt loam soil slopes to measure water flow velocity in rills under nine unit width flow rates (q) (0.17×10^{-3}, 0.33×10^{-3}, 0.67×10^{-3}, 1.33×10^{-3}, 2.67×10^{-3}, 5.33×10^{-3}, 10.67×10^{-3}, 21.33×10^{-3}, and 42.67×10^{-3} m^{3}/(s.m)) combined with four slope gradients (8.7%, 17.6%, 26.8%, and 36.4%), in which mobile bed rills were monitored. For unit flow velocity under q ≤ 1.33×10^{-3 }m^{2}/s, independence of flow velocity to slope was obtained. However, the results indicated that slope gradient combined with a higher unit flow rate contributed to better velocity prediction and fitted with a segmented equation well (R^{2} =0.95). A feedback mechanism was able to verify that the increase in roughness directly dissipated flow energy to reduce flow velocity, but cannot completely counterbalances steep slope effect. The experimental results showed that erosion-caused morphological changes on soil slopes reduce flow velocity by half due to an increase in bed roughness. Therefore, the current experimental measurements considering a wide range of flow rate and slope gradient conditions is useful to reveal the steep slope effect in mobile bed rills. The analysis showed that, for the investigated conditions, the flow velocity is a slope gradient- and flow rate dependent parameter.

Keywords: Flow velocity; Flow rate; Slope gradient; Model fitting; Slope morphology

9. A comparison between artificial neural network algorithms and empirical equations applied to submerged weir scour evolution prediction

Dawei Guan, Jingang Liu, Yee-Meng Chiew, Jian-Hao Hong, Liang Cheng

Pages 105-114 Download PDF

Abstract: Estimating the time evolution of a local scour hole downstream of submerged weirs can help determine the maximum scour depth and length and is essential to designing submerged weir foundations. In the current study, artificial neural networks with a backpropagation learning algorithm were used to estimate the temporal variation of scour profiles downstream of submerged weirs under clear water conditions. Physical factors, such as the flow condition, weir size, and sediment characteristics, are general scour considerations. Two sets of data combinations, namely original and non-dimensional data, were utilized in developing the backpropagation network (BPN) model. Using the data combinations and a trial-and-error method, the appropriate number of hidden neurons in the model architecture was determined. The results indicated that using non-dimensional variables as inputs in estimating the time evolution of scour holes downstream of a submerged weir is more suitable for the BPN model. Comparisons of the prediction results of the BPN model and an empirical regression formula revealed that the BPN model was more accurate and more direct in predicting the temporal variation of the local scour hole profile. In addition, sensitivity analysis showed that the dimensionless time exerted the most significant impact on the time evolution of the non-dimensional scour hole profile.

Keywords: Submerged weir; Scour profile; Artificial neural networks (ANNs); Time evolution; Backpropagation

10. Geobag stepped spillway for check dams: A pilot study

Shu Yu, Fan Yue, Qiang Zhang, Zuyu Chen, Penghai Yin, Jianwei Hao, Laizhang Zhang , Ludong Hao

Pages 115-127 Download PDF

Abstract: Check dams are widely used worldwide for the soil and water conservation. Many of them have no spillways, resulting in frequent dam breach failures during heavy rainfall events. This paper proposes a new geobag stepped spillway for small check dams. The structure of the spillway primarily consists of a stepped chute created from geobags filled with local soil compacted and consolidated with a small amount of cement. The developed composite geosynthetic material exhibits water erosion resistance, high strength against puncture, and high tensile strength. To examine the feasibility of the proposed geobag stepped spillway, a prototype pilot test was designed and constructed in a check dam in Shaanxi Province, China, with a height of 10 m and a downstream slope of 1 (vertical) to 2 (horizontal). More than 30 overflow tests were done for a geobag stepped spillway under uncontrolled and gated weir flow conditions. Based on the measurements of flow velocities and flow depths of four cross sections, it was observed that the energy dissipation ratio ranged between 73.8% and 92.8% for all the examined conditions. In addition, no significant deformation of the geobag stepped spillway was observed, although the maximum flow velocity at the spillway toe was 6.7 m/s. This study confirms that the proposed geobag stepped spillway is a promising approach for providing an effective, safe, and economical flood release structure for small check dams.

Keywords: Geobag stepped spillways; Check dams; Composite geosynthetic material; Energy dissipation

11. Deep learning long short-term memory combined with discrete element method for porosity prediction in gravel-bed rivers

Duong Tran Anh, Ahad Hasan Tanim, Daniel Prakash Kushwaha, Quoc Bao Pham, Van Hieu Bui

Pages 128-140 Download PDF

Abstract: The porosity of gravel riverbed material often is an essential parameter to estimate the sediment transport rate, groundwater-river flow interaction, river ecosystem, and fluvial geomorphology. Current methods of porosity estimation are time-consuming in simulation. To evaluate the relation between porosity and grain size distribution (GSD), this study proposed a hybrid model of deep learning Long Short-Term Memory (LSTM) combined with the Discrete Element Method (DEM). The DEM is applied to model the packing pattern of gravel-bed structure and fine sediment infiltration processes in three dimensional (3D) space. The combined approaches for porosity calculation enable the porosity to be determined through real time images, fast labeling to be applied, and validation to be done. DEM outputs based on the porosity dataset were utilized to develop the deep learning LSTM model for predicting bed porosity based on the GSD. The simulation results validated with the experimental data then segregated into 800 cross sections along the vertical direction of gravel pack. Two DEM packing cases, i.e., clogging and penetration are tested to predict the porosity. The LSTM model performance measures for porosity estimation along the z-direction are the coefficient of determination (R^{2}), root mean squared error (RMSE), and mean absolute error (MAE) with values of 0.99, 0.01, and 0.01 respectively, which is better than the values obtained for the Clogging case which are 0.71, 0.14, and 0.03, respectively. The use of the LSTM in combination with the DEM model yields satisfactory results in a less complex gravel pack DEM setup, suggesting that it could be a viable alternative to minimize the simulation time and provide a robust tool for gravel riverbed porosity prediction. The simulated results showed that the hybrid model of the LSTM combined with the DEM is reliable and accurate in porosity prediction in gravel-bed river test samples.

Keywords: Numerical modeling; Discrete element method; LSTM; Bed porosity; Gravel-bed river

12. Assessment of equilibrium pressure-flow scour depth using jet flow theory

Mostafa Koushki, Mohammad R. Chamani, Mohammad N. Moghim

Pages 141-151 Download PDF

Abstract: Most models for predicting pressure-flow scour depth are based on use of the continuity and energy equations. The current study presents a model to predict pressure-flow scour depth using the momentum equation considering the jet flow deflected by the bridge deck. When approaching the bridge deck, the upstream flow acts as a jet flow that deviates toward the bed. Below the bridge deck, a combined jet-flow is created as a result of merging the initial jet-flow and the pressure-flow. The continuity equation is used to determine the thickness of the separation zone and the combined jet-flow angle. Equations are presented to estimate the combined jet-flow velocity and the thickness of the combined jet-flow. The study results reveal that the flow intensity, submergence ratio, and relative separation zone thickness are the principal parameters affecting the pressure-flow scour depth. The equation proposed in this study shows satisfactory accuracy to predict the equilibrium pressure-flow scour depth for a relative opening height of the bridge deck greater than 0.25. For relative opening heights of the bridge deck less than 0.25, insufficient duration of tests is a limitation of the available data to verify the proposed equation.

Keywords: Scour; Pressure-flow; Separation zone; Jet-flow; Momentum equation; Bridge deck