Papers Published in the International Journal of Sediment Research Vol.37 No.4 2022

Volume 37, No.4, 2022

Pages 411-537 (August 2022)

2. Two-dimensional modeling of channel evolution under the influence of large-scale river regulation works
Meirong Zhou, Junqiang Xia, Shanshan Deng, Zhiwei Li
Pages 424-434

3. A new mixing equation for bed material composition in bed form dominant conditions
Baozhen Jia, Deyu Zhong
Pages 435-446

4. Using a fluvial archive to place extreme flood sediment (dis)connectivity dynamics in context of a longer-term record
Kirstie Fryirs, Chris Thompson, Damian Gore
Pages 447-456

6. Numerical model of local scour considering the unsteady sediment inflow and sediment sorting: Application to scour upstream of slit weir
Kazuyuki Ota, Takahiro Sato, Ryosuke Arai
Pages 469-483

8. Ability of soil bacterial composition as an indicator of levels of soil erosion in a badland
Gaetano Guida, Vincenzo Palmeri, Luca Settanni, Raimondo Gaglio, Marco Tolone, Vito Ferro
Pages 493-504

9. Non-equilibrium concentration profile formulas of suspended sediment and their preliminary applications
Zipu Ma, Qingchao Guo, Jianzhao Guan, Maohua Le
Pages 505-513

11. Analytical approach for predicting local scour downstream of submerged sluice gate with an apron
Arsalan Mostaani, Amir H. Azimi
Pages 522-537

1. Particle image velocimetry evaluation of flow-altering countermeasures for local scour around a submerged circular cylinder
Priscilla Williams, Ram Balachandar, Vesselina Roussinova, Ronald Barron
Pages 411-423 Purchase PDF
Abstract: The effect of scour countermeasures on the mechanism of local scour around a cylinder requires clarification in order to develop design methodology for use in practice. Previous investigations on countermeasure performance, though useful, have not provided adequate measurements to support this understanding. In the present investigation, particle image velocimetry (PIV) measurements were acquired at several streamwise-vertical planes in the flow field surrounding a submerged circular cylinder with a vertical splitter plate and with a rectangular collar (a horizontal base plate). Analysis of the distribution of mean streamwise velocity and Reynolds shear stress as well as the scour formation indicated that the splitter plate disrupted shear layer interaction in the wake region, reducing the width of scour downstream of the cylinder by 3%. The collar eliminated scour upstream of the cylinder entirely by providing protection at the sides of the cylinder where the shear stress exceeds the critical bed shear stress, and the streamwise velocity distribution in the region between the cylinder and the channel sidewall indicated that installation of a rectangular collar causes flow separation at a point further upstream on the cylinder surface.
Keywords: Scour and erosion; Local scour; Pier scour; Scour countermeasures; Hydraulic modelling; Particle image velocimetry (PIV)

2. Two-dimensional modeling of channel evolution under the influence of large-scale river regulation works
Meirong Zhou, Junqiang Xia, Shanshan Deng, Zhiwei Li
Pages 424-434 Purchase PDF
Abstract: In the middle and lower reaches of alluvial rivers, various kinds of river regulation projects affecting natural channel evolution often are distributed due to the requirements of flood control, navigation, and channel stability. However, the influence of large-scale river regulation works on fluvial processes is not fully known. Therefore, a two-dimensional (2D) morphodynamic model has been improved to address this problem. The new detailed procedure is presented in this paper: (i) First, each node in the study domain was labeled using a specified point code to distinguish the zones with or without regulation works; and (ii) second, a 2D model was improved to consider the effect of river regulation works. In the refined model, the modules of sediment transport and bed deformation were treated separately in different zones. In the unprotected zones, both bed deposition and erosion were likely to occur. In the protected zones, bed erosion could not occur owing to the protection provided by the river regulation works, unless there was a deposition layer newly formed over the previous simulation periods. The observed data of the years 2004 and 2008 were used to calibrate and verify the improved 2D morphodynamic model which was applied in a 68-km-long reach of the Middle Yangtze River. Satisfactory results were obtained indicating that the improved model can better simulate the process of sediment transport and the morphology adjustment in three central bars in the study reach.
Keywords: Two-dimensional model; River regulation works; Channel evolution; Central bar; Middle Yangtze River

3. A new mixing equation for bed material composition in bed form dominant conditions
Baozhen Jia, Deyu Zhong
Pages 435-446 Purchase PDF
Abstract: Vertical mixing beneath the bed surface and its effect on sediment composition has long been underestimated. This paper proposes a mixing equation to illustrate the temporal and spatial variations of bed material composition for bed form dominant rivers. A continuous mass conservation equation for elevation-specific nonuniform bed material composition is initially presented. A vertical mixing equation is finally derived as a diffusion-type partial differential equation with a source term characterized by a vertical diffusion coefficient and the geometric dimensions of bed forms. Coupled with boundary conditions, this equation is further developed in a vertical mixing model at the scale of bed forms, in which the variations of bed material composition are clearly illustrated. The equation accounts for vertical exchange fluxes driven by bed form migration and their effect on bed material composition, which helps elucidate the mixing mechanism. In application to riverbed degradation, the proposed equation is capable to describe armoring development in consideration of the interior mixing, which provides more satisfying predictions for bed surface materials. The new mixing equation helps gain insight into predicting the variations of bed material composition during morphological changes.
Keywords: Mixing equation; Active layer; Bed forms; Grain size distribution

4. Using a fluvial archive to place extreme flood sediment (dis)connectivity dynamics in context of a longer-term record
Kirstie Fryirs, Chris Thompson, Damian Gore
Pages 447-456 Purchase PDF
Abstract: The aim of this study was to establish the source and provenance of sediments deposited in a large floodplain sink during extreme floods in the Lockyer Creek catchment, Australia, in 2011 and 2013. We place the sediment source patterns in context of the longer-term record to determine whether coarse-grained sediment sources (i.e., very fine sand to very coarse sand) and the spatio-temporal pattern of (dis)connectivity have changed over time. We do this by matching the geochemical properties and age structure of a sediment profile located in a downstream floodplain sink to the elemental composition of source sediments. One hundred and fifty-seven sediment samples from 20 sites across the catchment are analysed using X-ray fluorescence (XRF) spectrometry to compare the elemental ratio composition of the downstream floodplain sink to its source materials. We use Optically Stimulated Luminescence (OSL) dating to determine the age structure of the sediments in the floodplain sink. The northern tributaries and parts of the Lockyer River trunk stream are the primary sources of coarse sediment. These areas are connected (coupled) to the lower trunk stream and floodplain sediment sink. Southern tributaries are largely disconnected (decoupled) and supply little sediment to the floodplain sediment sink. This pattern of sediment source contribution has remained similar over the last 6.8 ka at least. Sediment sources as observed in the 2011 flood have predominated over the mid-late Holocene whilst those in the 2013 flood are rare.
Keywords: Sediment provenance; Geomorphology; Sediment source; Sediment sink; Lockyer Valley

5. Grain size characteristics of surface sediment and its response to the dynamic sedimentary environment in Qiantang Estuary, China
Shanshan Wang, Cunhong Pan, Dongfeng Xie, Mingwei Xu, YuhanYan, Xinwen Li
Pages 457-468 Purchase PDF
Abstract: The composition and grain size characteristics of sediment in estuarine and coastal environments provide important information on the material source, hydrodynamic environment, environmental events, etc. However, few studies have focused on the sediment characteristics of the entire Qiantang Estuary, particularly, on the correlation between hydrodynamics and sediment properties. Through systematic sampling of the surface sediment in a large area of the Qiantang Estuary, the spatial distribution characteristics of the surface sediment of the Qiantang Estuary, such as the grain size composition and particle size parameters, in different sections of the estuary area are analyzed. By comparing the particle size data of different estuaries, the similarities and differences of the particle size parameters of the Qiantang Estuary and other estuaries are compared and analyzed. According to the differences in the sediment composition, the distribution status of the particle size frequency curves and the morphological characteristics of the probability curves in the entire study area, the Qiantang Estuary is divided into 7 dynamic depositional areas: Fuchunjiang Hydropower Station–Fuyang, Fuyang–Qibao, Qibao–Cao'e River, Cao'e River–Zhapu, North Shore of Hangzhou Bay, middle part of Hangzhou Bay, and South Shore of Hangzhou Bay, which are different from the previous estuary segmentation system. The study area is divided into 13 dynamic depositional sub-regions using the Pejrup M triangle diagram. Combining the calculation results of the mathematical model and the Pejrup M triangle diagram, the relation between the dynamic deposition environment and the bottom shear stress is discussed. It is found that the spatial distribution of the bottom shear stress in the study area is in good agreement with the zoning of the dynamic sedimentary environment.
Keywords: Qiantang Estuary; Surface sediment; Grain size parameter characteristics; Dynamic sedimentary environment

6. Numerical model of local scour considering the unsteady sediment inflow and sediment sorting: Application to scour upstream of slit weir
Kazuyuki Ota, Takahiro Sato, Ryosuke Arai
Pages 469-483 Purchase PDF
Abstract: The current study proposes a novel framework for the numerical model for estimating the temporal scour considering unsteady sediment inflow and the sediment sorting process. The framework was applied to local scour upstream of a slit weir. The scour model is based on an ordinary nonlinear differential equation derived from sediment continuity and scour rate equations. A one-dimensional (1-D) Boussinesq-type model coupled with nonequilibrium sediment transport was incorporated in the scour model to consider unsteady sediment inflow. In addition, a mixing layer approach was incorporated to determine temporal variations in particle size in the scour hole. The proposed framework was validated using scour experiments conducted under conditions that include non-uniform sediment, live-bed scour, and unsteady flow rate. The simulation results showed satisfactory agreement with experimental results for the scour upstream of a slit weir. The proposed model appropriately explained the hysteresis process for flow unsteadiness, refilling process for live-bed scour, and armoring process for non-uniform sediments. In addition, the model framework proposed in the current study is applicable to local scour around other hydraulic structures (e.g., bridge piers) upon establishing the scour rate equation. Therefore, the current study provides a novel approach for modeling temporal scour that is required to consider unsteady sediment inflow and sediment sorting.
Keywords: Local scour; Temporal scour; Mixing layer theory; Slit weir; Non-equilibrium bed load

7. Sediment budget and riverbed deformation in the uppermost part of the lower Yangtze River, China
Shuwei Zheng, Huanlong Luo, Jiayue Zhang, Heqin Cheng, Zijun Li, Yugai Ma, Shuaihu Wu, Enfeng Liu
Pages 484-492 Purchase PDF
Abstract: The Yangtze River (YR), similar to most large rivers in the world, has experienced significant changes in its depositional environment due to anthropogenic disturbances and climatic influences in recent decades. However, knowledge of how the river channel and bed deformation respond to these changes in the uppermost part of the lower YR, a 200-km-long branched channel, is limited. In the current study, historical bathymetric data collected from 1992 to 2013 and high-resolution multibeam echo sounder (MBES) data obtained from 2015 to 2016 were analyzed to address the changes in the depositional environment. The results indicate that the whole riverbed in the Hukou to Datong reach (HDR) has been scouring over the past two decades and this trend is expected to continue in the future due to decreasing sediment supply from the upper watershed. The amount of net erosion from the HDR during 1992–2013 approximately accounted for 7.2% of total sediment load in the Yangtze River (5.02 billion metric tons at Datong). The evolution of the riverbed is trending towards stabilization even though the patterns of erosion and/or deposition in the HDR have dramatically changed in the last two decades. The part of the channel from the upper 100 km to Datong was found to be a sensitive reach that first showed erosion from 1992 to 2003 and showed deposition during 2003–2008, and then mild erosion during 2008–2013 in response to environmental changes. Thus, the findings indicate that riverine channel deformation in response to anthropogenic disturbance and climate influence is dynamic in different reaches, and this finding has both scientific and practical significance in terms of understanding channel stability and its response to external stressors.
Keywords: Depositional environment; Channel deformation; Anthropogenic disturbance; Three Gorges dam; Yangtze River

8. Ability of soil bacterial composition as an indicator of levels of soil erosion in a badland
Gaetano Guida, Vincenzo Palmeri, Luca Settanni, Raimondo Gaglio, Marco Tolone, Vito Ferro
Pages 493-504 Purchase PDF
Abstract: Calanchi (plural of calanco) are typical Italian badlands created by a combination of morphogenetic processes (rill and interrill erosion, gullying, piping, and mass movements) mainly originated by the effect of water. Calanchi are characterized by the sparse and patchy distribution of vegetation, and, in interplant areas, the soil surface is colonized by an association of organisms known as biological soil crust (BSC). A morphometric analysis of 45 basins in the studied calanchi area, based on a high-resolution digital elevation model, showed those basins are sediment removal systems characterized by rapid and relevant erosion processes. The goal of the current research is to evaluate the bacterial composition of BSC and to recognize its signature of land degradation processes in soil samples by a microbiological analysis (culture-dependent and culture-independent approaches). Soil bacterial distribution was investigated by a culture-independent approach, applying Illumina technology in soils with different vegetation cover. Four species were detected in site A (bare soil). In sites B (sparse vegetation) and C (densely vegetated soil) 19 and 18 bacterial taxa were detected, respectively. Sites B and C were characterized by 17 species in common. The microbial communities detected at sites B and C are typical of environments unable to support vegetation and microorganisms that are not specialized to live in these environments. Biodiversity analysis of the bacterial communities of biocrusts, done using richness and evenness indices, confirmed that the composition of the BSC communities can be a signature of the intensity of soil erosion processes.
Keywords: Calanchi; Biological soil crust; Soil bacteria; Vegetation cover; Water erosion

9. Non-equilibrium concentration profile formulas of suspended sediment and their preliminary applications
Zipu Ma, Qingchao Guo, Jianzhao Guan, Maohua Le
Pages 505-513 Purchase PDF
Abstract: The vertical concentration profiles in non-equilibrium sediment transport processes generally deviate from the equilibrium concentration distribution of suspended sediment. The non-equilibrium concentration profile formulas currently available are those of Han and Brown, respectively. However, the complexity of these formulas limits their use in practical calculations. To improve the usefulness of these formulas, the unknown parameters in Han's formula are reduced from three to two, and the three different forms of Brown's formula are transformed into one. These formulas then are proved to be essentially the same to some extent, and only different in the expression form of the exponent. Han's formula then is improved, based on which the theoretical calculation methods and distribution characteristics of non-equilibrium profiles are presented. Han's and Brown's formulas are verified qualitatively and quantitatively. Finally, these formulas are applied in the investigation of the characteristics of certain physical quantities, such as the recovery factor of sediment concentration, near-bottom sediment flux, and the non-equilibrium Péclet number in the non-equilibrium sediment transport process. These results clearly reveal that the magnitude of these physical quantities decreases in the erosion process and increases in the deposition process. The results also show that the formulas are largely applicable for the non-equilibrium sediment transport conditions.
Keywords: Suspended sediment; Vertical concentration profiles; Non-equilibrium sediment conditions; Non-saturation parameter; Péclet number

10. Relationship between the equilibrium morphology of river islands and flow-sediment dynamics based on the theory of minimum energy dissipation
Xuhai Yang, Zhaohua Sun, Jinyun Deng, Dongfeng Li, Yitian Li
Pages 514-521 Purchase PDF
Abstract: River islands are vital geomorphic units in alluvial rivers, and the variation of their morphology and position plays a significant role in regulating flow-sediment transport and channel stability. Based on the theories of minimum energy dissipation theory of fluid movement and river morphodynamics, this study uses the river islands in anabranching channels to analyze the relationship between the shape coefficient of river island and the flow-sediment dynamics under stable equilibrium conditions. Results indicate that the river islands could adjust their lengths and widths to reach an appropriate allocation of flow diversion ratio and sediment separation ratio in the two anabranching channels to ensure flow-sediment being smoothly transported downstream and achieve the minimum energy dissipation. Under the minimum energy dissipation condition of flow-sediment transport balance, the ratio of “sediment separation ratio” to “flow diversion ratio” in short and straight branching channels is between 1 and 1.1. When the proportion of flow-sediment transport reaches its maximum, the steady island morphology coefficient is approximately 0.2; that is, the island length is five times the width. We verify the steady island morphology coefficients using two typical islands in the middle and lower reaches of the Yangtze River and find the relative error is within ±3%.
Keywords: Equilibrium morphology of islands; Flow-sediment dynamics; Minimum energy dissipation theory; Sediment separation ratio; Flow diversion ratio

11. Analytical approach for predicting local scour downstream of submerged sluice gate with an apron
Arsalan Mostaani, Amir H. Azimi
Pages 522-537 Purchase PDF
Abstract: A new analytical method was evaluated for predicting scour profile downstream of a submerged sluice gate with an apron. The differential equations between bed Shear stress and Scour profile Curvature (SSC model) were utilized to predict the scour profile in both temporal and equilibrium stages. A jet momentum flux was considered as an external source of erosion on a hypothetical particle ring as the boundary between the flow and sediment bed. The scour length and sediment resistance factor were the two unknowns in the governing differential equations. Two solution strategies were introduced to provide a closed-form solution by using the prediction equations of maximum scour depth from the literature and by employing the von Kármán momentum integral equation. The first strategy was used to investigate the effect of jet angle of attack and the angle of the maximum scour slope on the prediction of scour profile. A sensitivity analysis was performed to determine an acceptable range for the maximum scour slope. The shear stress at the location of maximum scour was also estimated using the von Kármán momentum integral equation and the model was modified for erodible curved beds. The modified von Kármán equation was linked with SSC equations to predict the characteristic lengths of scour in temporal and equilibrium stages. Variations in bed shear stress at the location of maximum scour depth decreased non-linearly with time and reached the sediment critical shear stress at equilibrium. Four hydrodynamic regimes were classified to define the temporal variations of bed shear stress. The maximum error for prediction of scour profile with time occurred at the beginning of scour and the proposed model overestimated the maximum scour depth by 34.8% and underestimated the scour length by 7.6%.
Keywords: Erosion; Scour; Turbulent wall jet; Sediment transport; Bed shear stress; von Kármán momentum integral equation