Sediment Size Research Articles

Geomorphology shapes relationships between animal communities and ecosystem function in large rivers

Understanding how the Earth's surface (i.e. ‘nature's stage') influences connections between biodiversity and ecosystem function (BEF) is a central objective in ecology. Despite recent calls to examine these connections at multiple trophic levels and at more complex and realistic scales, little is known about how landscape structure shapes BEF relationships among animal communities in nature. We coupled high‐resolution habitat mapping with extensive field sampling to quantify connections among the geophysical habitat templet, invertebrate assemblages and secondary production in two large North American riverscapes. Patterns of sediment size governed invertebrate assemblage structure, with particularly strong effects on composition, richness and taxonomic and functional diversity. These relationships propagated to drive positive relationships between biodiversity and secondary production that were modified by scale, context‐dependencies and anthropogenic modification. Finally, leveraging spatially‐explicit descriptions of geophysical and biological properties, we uncovered distinct and nested spatial scales of biodiversity and secondary production, and suggest that multiple geophysical processes simultaneously influence these patterns at different scales. Together, our findings advance our understanding of relationships between the physical templet and patterns of BEF, and help to predict how perturbations to the Earth's surface may propagate to influence biodiversity and energy flux through food webs.

Migration and Diffusion of Surface Sediments in Bohai Bay: Evidence from Grain Size and Elements

Grain size and element content of surface sediment from Bohai Bay were analyzed to study the sediment migration and diffusion based on grain size trend analysis (GSTA) and discriminant function (DF). The sediment in the southern, central and western part of Bohai Bay mainly originates from the Yellow River, while that in the northern part of Bohai Bay mainly originates from the Luanhe River. The influence boundary between the Yellow River and the Luanhe River is estimated to be at 38°50′ N. In both the southern and northern parts of Bohai Bay, sediment is transported into the bay under the influence of prevailing waves, strongest waves and tidal remnants, resulting in sediment accumulation in western Bohai Bay. The coastal sediment of Bohai Bay is generally in a state of offshore movement, which is consistent with the large-scale coastline retreat in past decades found by previous studies.

Solid-liquid interface adsorption of antibiotic resistance plasmids induced by nanoplastics aggravates gene pollution in aquatic ecosystems

Antibiotic resistance genes (ARGs) and nanoplastics (NPs) have been identified as emerging pollutants in water environment; the interactions between antibiotic resistance plasmids (ARPs) and NPs will influence ARG transport in sediments. Herein, the adsorption experiments of a typical ARP onto polystyrene nanoplastics (PS-NPs) in river and lake sediments were conducted to elucidate the adsorption mechanisms and the effects of environmental factors. Results indicated that the adsorption amounts of PS-NPs increased with the dosages while decreased with the particle size of sediments. Multi-layer adsorption of PS-NPs was found to exist mainly in sand and silt sediments, whereas the filling adsorption dominated in the clay. Moreover, the adsorbed PS-NPs enhanced the physisorption of ARPs in sediments through stimulating the intraparticle diffusion of ARPs induced by electrostatic force. Besides, the adsorption amounts of ARPs onto the PS-NPs decreased with the increasing pH and dissolve organic matter due to the enhanced electrostatic repulsion and competitive adsorption. The ion strength played catalytic roles by increasing the electrostatic attraction and adsorption sites of ARPs on PS-NPs. The adsorbed ARPs in sediments were closely related with the ARGs in extra/intracellular DNA of biofilms, influencing the distribution and proliferation of ARGs largely. The findings indicate that ARG-associated pollution might be enhanced by the solid-liquid interface adsorption induced by NPs, which was controlled by pH, ion strength and dissolve organic matter. This study provides supplementary insights into the roles of NPs as carriers of ARP in sediments, and advances our understanding on the risks of NP-ARG co-occurring contamination in aquatic ecosystems.

Stream nitrogen uptake associated with suspended sediments: A microcosm study

Despite significant advances in our understanding of nitrogen (N) removal pathways along river networks, the role of water column processes remains largely understudied. This knowledge gap not only limits our capacity to determine N transport and retention in mid-to-large rivers but also hampers our understanding of N removal processes in smaller streams during stormflow conditions, in which significant increases in suspended sediment concentrations (SSC) typically occur. High SSC in the water column can provide abundant substrate for microbial growth and water column N uptake. However, storms of different size mobilize different quantities of sediment of varying properties and sizes, which can ultimately modulate water column N uptake rates in the stream during stormflows. To assess water column N uptake associated with suspended sediment particles of different sources and sizes, we quantified assimilatory and dissimilatory N uptake rates in a set of microcosms representing a gradient of sediment properties (organic matter, N content, and microbial activity) and surface area (fine vs. coarse size) availability. Water column assimilatory uptake (Used) ranged from 12.7 to 187.8 µg N [g sediment]−1 d−1 across all sediment sources and size fractions, and was higher on average than denitrification rates (DNsed) in agricultural and stream bank sediments but not in streambed sediments (mean DNsed = 240.9 ± 99 µg·N [g sediment]−1·d−1). Sediment-bound C in suspended sediment varied among sediment sources and was directly related to Used rates, but not to DNsed rates, which were less predictable and more variable. Overall, our results showed a positive nonlinear relationship between water column N uptake and SSC, while indicating that water column N uptake may scale differently to SSC depending on sediment source, and to a lesser degree, particle size. Because low, moderate, and large storms can mobilize different quantities of sediment in the watershed of different sources and sizes, it is likely that storm size will ultimately modulate the contribution of water column uptake during storm events to whole-reach N retention.

Quantifying the effects of sediment transport on river channel geometry and flood level – a case study of the December 2014 flood

ABSTRACT Rapid urbanization has an accelerated impact on catchment hydrology and geomorphology due to land use and land cover changes as a result of anthropogenic development activities in river catchment areas that cause increased surface runoff and higher sediment yield. The present study investigates the channel changes and sediment transport phenomena, including bed material movement from the upstream to the estuaries of the Pahang River Basin, Peninsula Malaysia. The river geometry survey associated with the spatial variation in sediment transport has confirmed that changes in river bed profile occur due to the erosion and sediment deposition along the Pahang River. The sediment size distribution for the Pahang River was very coarse sand and gravel after the December 2014 flood . The river geometry survey showed a gentle slope that can induce lower discharge typical of alluvial rivers relating to flood events. Quantitative assessment of sediment load is, therefore, of critical importance for future river basin management.

GAIA - a unified framework for sediment transport and bed evolution in rivers, coastal seas and transitional waters in the TELEMAC-MASCARET modelling system

In rivers, coastal seas and transitional waters, sediment transport processes involve a variety of interacting factors that dynamically vary over time and space. The flow dynamics within these highly heterogeneous natural systems influences the spatial patterns of erosion and deposition of the bed sediments, which in turn shapes and conditions the bottom morphology. By taking advantage of the established modelling framework in both two- and three dimensions for unstructured meshes proposed within the Telemac-Mascaret system, the new module Gaia provides a code structure for solving sediment transport and morphological evolution problems. By a clear treatment of sedimentary processes that happen in the water column, in the bed structure, and at the water–bed interface, Gaia efficiently manages the spatial and temporal variability of sediment size classes, properties and transport modes for two- and three dimensions. In addition, this module can easily be expanded and customised to particular requirements by modifying user-friendly, easy-to-read, and well-documented FORTRAN-90 subroutines.

A 3D numerical and experimental parametric study of wave-induced scour around large bluff body structures

This is the first study to undertake a comprehensive parametric study of wave-induced scour around a large bluff body structure, and also presents experimental data to validate a CFD model for wave-induced scour around the structure. A parametric study is undertaken using the REEF3D CFD model for varying incident wave condition (depth, wave amplitude, frequency, and direction), structure geometry (width, length, and corner curvature), and sediment size. The numerical model is validated against experimental datasets, demonstrating that the model can accurately replicate scour around large bluff body structures.Two new equations are proposed for prediction of non-dimensional equilibrium scour depths at the front and back corners of a large bluff body structure using the Keulegan-Carpenter (KC) number based on 18 and 24 datapoints respectively. The equations are valid within the following limits: 0.37 ≤ KC ≤ 1.75, 0.10 ≤ B/λp and 0.14 ≤ L/λp, where B and L are the structure width and streamwise length, and λp is the peak wave length. It is further demonstrated that the non-dimensional scour depth does not vary significantly with the sediment size (for 0.075 ≤ θ ≤ 0.117 where θ is the Shields parameter), or the structure width/length for the limits stated above.

Historical development of the Regime Geometry Equations, Part-I

The present study intended to review the historical development of the regime geometry equations proposed by many researchers since 1895. Kennedy started the search for the attributes of stable channels on the Upper Bari Doab Canal of Punjab in 1980-1984. The regime concept was presented by Lindley (1919) that later on Lacey (1930) modified to a set of most widely used regime relations. Later on, Blench (1941-1957), and Simons and Albertson (1960) presented their equations. This period is called ‘canal regime period’ because most of the research focused on canal design. The concept of regime was extended to river systems by Leopold and Maddock in 1953. In 1963, Henderson proposed some regime equations that can be applied for predicting canal and river geometry. This period was the transition from canal regime period to river regime period and from an empirical approach to analytical approach and is called as ‘Transitional Period’. Many other researchers written the information based on analytical approach, or a combination between analytical and empirical approaches, and more focused to river regime especially gravel bed river regime. This period is, called ‘River regime period’. Flow discharge, sediment size, and bed-load sediment are the three main factors that influence the geometry of alluvial channels. The hydraulic geometry relationships indicate that sediment size and bed-load sediment strongly influence the channel slope, moderately influence the flow velocity, and slightly influence the channel depth and the channel width. This study also shows that in terms of Shields parameter, the exponents of discharge, sediment size, and sediment transport are dependent on the relative submergence (D/d50).

Relationship between the size composition observed from the photosedimention technique and chromaticity of the fine-grained surface sediments from the modern lakes, Songnen Plain

The relationship between clay particle size in fine-grained sediments and the enrichment of organic matter and the redox degree of their environment is conducive to the judgment and evaluation of the hydrocarbon generation potential of fine-grained sediments. The grain size characteristics of clay particles in the surface fine-grained sediments of Chaersen lake, Delong lake, Hongyuan lake, Lamasi lake, and Zhongnei lake in Songnen Plain are revealed by light sedimentation method. On the basis of the test, the relationship between the particle size of clay particles and the sediment chromaticity is analyzed, and the directivity of chromaticity to the content of organic matter and redox degree of fine-grained sediments is used for the organic content estimation. It is confirmed that the particle size of clay is negatively correlated with its organic matter content and positively correlated with its redox degree. This has important reference significance for discussing the hydrocarbon generation potential and evaluation of Cretaceous lacustrine fine-grained source rocks in the Songliao Basin.

A multi-dimensional two-phase mixture model for intense sediment transport in sheet flow and around pipeline

A two-phase mixture model is developed to simulate intense sediment transport covering the bed-load layer and suspended load layer. The proposed model maintains high accuracy as an Eulerian two-phase model but requires low computational cost. The proposed model applies an analytical formula for relative velocity between phases. The dense granular flow rheology is employed to close particle stress economically. The closure of Reynolds stress considers turbulence damping and small-scale fluctuation of fluid–particle interaction and particle collision. A damping function is adopted in eddy viscosity for extra turbulence damping from inter-particle interaction. The optimal exponent of the damping function refers to sediment shape and size. The sediment diffusion includes turbulence diffusion and shear-induced self-diffusion originating from dense sediment. The proposed model is validated by several sets of sheet flow cases (Shields number Θ = 0.44–2.20 and particle Reynolds number Res = 1.6–603.0) and shows a wide applicable range and good accuracy. The small-scale fluctuation and shear-induced self-diffusion improve the computation in the lower sheet flow layer where volumetric sediment concentration is larger than 0.2. Furthermore, the proposed model shows reasonable applicability on the multi-dimensional pipeline scour development. The scour profiles are well predicted and the Brier Skill Score = 0.809. However, the proposed model does not perform the wake characteristic around the pipeline sufficiently, and slight scour difference exists between the simulation and experiment.

Stability of acidified milk drinks: Comparison of high hydrostatic pressure (HHP) and thermal treatments

There is a search for effective stabiliser activity and alternative pasteurisation techniques for acidified milk drinks (AMD). In the present study, AMD were prepared at three different pH (4.0, 4.5 and 5.0) and high methoxyl pectin (HMP) levels (0.2, 0.5 and 0.8%) by thermal (75 °C, 15 min) and high hydrostatic pressure (HHP) (100, 300 and 500 MPa, 5 min) treatments. To achieve minimum steric stability, 0.5% HMP was required. HMP at 0.5%, pH 4.0 and 4.5, produced high protein solubility (60–70%), low storage sedimentation (10–15%) and mean particle size values in the range of 1.70–3.00 μm for all samples. Heat treatment induced lower particle size variation than HHP treatment. Heat-treated samples also showed lower Turbiscan stability index (TSI) values and smaller delta backscattering (ΔBS) variations. Nonetheless, HHP could replace heat treatment at 0.5% HMP concentration and pH 4.0–4.5.

The response of Chudao’s beach to typhoon “Lekima” (No. 1909)

Abstract The response of beaches to typhoons has always been a hot topic at home and abroad. The study of beach changes during typhoons is helpful to deepen the understanding of beach evolution and is important for the coastal ecological environment. Based on the observation results of ten profiles and the sediment samples in Chudao before and after the typhoon Lekima, this article explored the response characteristics of the beach to the typhoon. The results showed that the study area was located on the right side of the typhoon’s forward path, and the double superposition of onshore waves and storm surge resulted in erosion along the beach. In order to alleviate the energy brought by storm waves, the beach was transformed into a more dissipated state. The mean particle size of the beach sediments was coarse on the whole, with poor sorting ability, and that in the wash zone was particularly obvious. The results showed that different profiles responded to Lekima in different ways: while the profiles of N01–N05 in the southwest changed little, those of N06–N10 in the northeast changed from the type of beach shoulder to the type of sandbank as a result of morphological differences in different profiles.

Sedimentary Response to Climate Change in the Central Bay of Bengal since the Last Glacial Maximum

Abstract As the largest submarine fan, the Bay of Bengal (BoB) captures the abundant environment and climate fingerprints on different time scales. To investigate the sedimentary response to climate change since the Last Glacial Maximum (LGM), an integrated survey was performed to study grain size, major, and trace elements (Al2O3, CaO, K2O, Na2O, TiO2, Sr, and Rb) of core BoB-24 sediments from the central BoB. The (K/Al)-TiO2 (%) relationship of the sediments was taken for the discrimination of provenance, which indicated that sediments from core BoB-24 in 24~6.5 cal ka BP were primarily from terrigenous material input from the Himalayas. In contrast, the material contribution from the Indian subcontinent increased distinctly since 6.5 cal ka BP. The rising sea level severed direct material supply, thus causing the evolution of sediment provenance of the central BoB. Meanwhile, the strengthened Indian summer monsoon (ISM) in the Holocene affected detrital material transport from offshore to the central BoB. After understanding the sediment provenance in the study, we choose the sensitive grain-size fraction to show the evolution of hydrodynamic conditions. The chemical index of alteration (CIA) and Ti/Ca and Rb/Sr ratios are calculated to indicate the change in terrigenous input and weathering intensity. The contents of sediment fraction from 11.05 to 15.63 μm, CIA, and ratios of Ti/Ca and Rb/Sr in core BoB-24 showed the same trends, which were low during the last deglaciation and late Holocene but high in the Early Holocene. The trends were strongly correlated with the variation of the Indian summer monsoon, indicating the possible impact of Indian monsoon on sediment transport in the Bay of Bengal. Alternative indicators such as the contents of ratios of Ti/Ca and Rb/Sr, CIA, and sensitive grain-size content in sediments of core BoB-24 jointly record the evolution history of ISM since 24 ka BP in the Bay of Bengal. Although the sensitivity and response of each indicator to the paleoenvironment and paleoclimate change are slightly different, on the whole, the change trend is the same. Specifically, four warm-cold alternating periods (Heinrich Event 1, Bølling/Allerød, Younger Dryas, and Early Holocene Climatic Optimum) had a strong signal in these proxies that indicated that the millennial-scale climate controls the terrigenous input to the Bay of Bengal, where a high value occurs in warm events and low value in cold events. The sedimentary pattern of the northeastern Indian Ocean provides scientific evidence for an insight into the regional response to global climate change and the long-term climate change trend of the human environment across the monsoon region.

Hydro-geomorphological regime of the lower Yellow river and delta in response to the water–sediment regulation scheme: Process, mechanism and implication

The water and sediment regulation schemes (WSRS) orientated by dams have profoundly adjusted the hydrological process and geomorphological evolution of the lower Yellow River and delta. Two decades since the implementation of WSRS, the observed multidisciplinary datasets allowed us to systematically evaluate the impacts of this unprecedented engineering effort on the river-coastal system. The sediment fluxes transported to the sea showed a notable rebounded and coarsened process due to the erosion of the riverbed during the WSRS periods. The average median grain size of suspended sediment increased from 17.7 μm in the 1990 s to 26 μm in 2002–2009. The natural rhythm of hydrological process is fundamentally altered by WSRS, about 50% and 30% of annual sediments and water delivered to the sea for only 20 days. The water discharge system is more temporally dynamic and complex with higher dimensionality after the operation of WSRS. The erosion pattern has been a dominant feature in all the channel segments downstream the Xiaolangdi Reservoir, with an average total erosion volume of 1.02 × 108 m3/a after the WSRS. However, the erosion efficiency of the lower river showed a decreased trend, due to the riverbed had formed a coarse armored substrate for the continued scouring since 2002. The YRD has changed from the pattern of erosion to progradation for the increase of sediment supply, and the average growth rate of subaerial delta was about 6.89 km2/a during 2003–2014. The lessons learned from the operation of WSRS may provide a valuable reference for the management of global large river systems.

Toward a general calibration of the Swiss plate geophone system for fractional bedload transport

Abstract. Substantial uncertainties in bedload transport predictions in steep streams have encouraged intensive efforts towards the development of surrogate monitoring technologies. One such system, the Swiss plate geophone (SPG), has been deployed and calibrated in numerous steep channels, mainly in the Alps. Calibration relationships linking the signal recorded by the SPG system to the intensity and characteristics of transported bedload can vary substantially between different monitoring stations, likely due to site-specific factors such as flow velocity and bed roughness. Furthermore, recent flume experiments on the SPG system have shown that site-specific calibration relationships can be biased by elastic waves resulting from impacts occurring outside the plate boundaries. Motivated by these findings, we present a hybrid calibration procedure derived from flume experiments and an extensive dataset of 308 direct field measurements at four different SPG monitoring stations. Our main goal is to investigate the feasibility of a general, site-independent calibration procedure for inferring fractional bedload transport from the SPG signal. First, we use flume experiments to show that sediment size classes can be distinguished more accurately using a combination of vibrational frequency and amplitude information than by using amplitude information alone. Second, we apply this amplitude–frequency method to field measurements to derive general calibration coefficients for 10 different grain-size fractions. The amplitude–frequency method results in more homogeneous signal responses across all sites and significantly improves the accuracy of fractional sediment flux and grain-size estimates. We attribute the remaining site-to-site discrepancies to large differences in flow velocity and discuss further factors that may influence the accuracy of these bedload estimates.

DISTRIBUTIONS OF 210PB, 137CS AND PHYSICAL PROPERTIES IN BOTTOM SEDIMENTS OF WEST NANAO BAY, JAPAN.

This study revealed sedimentation processes based on 137Cs and 210Pb distribution, grain size and magnetic susceptibility of bottom sediments in West Nanao Bay, Japan. Surface sediment concentrations and inventories of these radionuclides were relatively low in the middle and eastern areas of the bay and high in the western area, which has several major river mouths, suggesting that the contribution of riverine input affected only the western area. In the middle and eastern areas, the level of 137Cs inventory was much lower than that of the soils, and the excess 210Pb inventory was at the same level or lower. These results indicate that removal effects are stronger than accumulation effects (riverine input) in these areas. The patterns of radionuclides were consistent with the results, that grain size was relatively large in the middle and eastern areas, implying strong current conditions, and that fine sediment accumulated less in these areas.

Estimation of Fractal Dimension of Suspended Sediments from Two Mexican Rivers

Sampling programs for suspended sediment were carried out in the Usumacinta River and its tributary Grijalva River in Mexico during the years 2016 and 2017. Suspended sediment samples collected during these sampling programs were analyzed in the laboratory using a Rotating Annular Flume (RAF) fitted with a Particle Tracking Velocimetry (PTV) to obtain the 2D images of the suspended sediment particles as they were undergoing floc reconstruction, and subsequently using a glass settling column fitted with inline digital holography set up to obtain 3D holograms of the fully flocculated sediment particles. From these high-resolution hologram images, the fractal dimension of the flocculated sediment particles was obtained using the classical box-counting method and an improved Triangular box-counting method. The estimated fractal dimension of flocculated sediment, which is a measure of floc compactness and structure that control the settling velocity of flocculated sediment was used to validate two empirical models to estimate the fractal dimension in terms of the floc sizes of suspended sediments of these two rivers. It is shown in this study that the floc characteristic can be analyzed in laboratory experiments after floc reconstruction with the use of an RAF and it offers a viable alternative to the costly in-situ sampling that is often carried out in ocean research. The digital holography method employed in this research offers an efficient methodology to obtain the floc fractal dimension. Regarding the innovative aspects and new contribution to science, we can say that we have developed a laboratory protocol to test river waters to establish floc properties such as fractal dimensions of flocs in this research which will help to test river waters on a routine basis with manageable costs. We can also say that we have developed models to predict the relationship between floc fractal dimension and floc size, which did not exist before.

Factors controlling 137Cs distribution in bottom sediments of Koronowo Reservoir (Poland)

PurposeThe main aim of this study was to investigate factors influencing the long-term distribution of 137Cs activity concentrations in the bottom sediments of the dam lake, Koronowo Reservoir, 32 years after the Chernobyl nuclear power plant accident. For this purpose, selected properties of the collected sediment samples, such as grain size, mineralogical composition, and organic matter (OM) content, were investigated.Materials and methodsThe samples of lake sediments were collected with a Kayak-type gravity corer. The spatial and vertical distributions of 137Cs and 40K activity concentrations in the bottom sediments were investigated based on gamma spectrometry measurements. The particle size distribution of surface lake sediments was determined using a laser particle size analyzer. SEM and XRD were used for the mineralogical analysis of the collected sediment samples. Additionally, the content of organic matter was examined in all samples using an elemental analyzer.ResultsThe 137Cs content was significantly elevated in the case of fine-grained (< 63 µm) surface lake sediments (classified as silts, which are deposited in the profundal zone of Koronowo Lake) and ranged from 12.5 ± 4.1 to 29.2 ± 4.0 Bq kg−1. It was found that the increased concentration of 137Cs activity is more closely related to the content of the silt fraction (2–63 µm) than to the clay fraction (< 2 µm) in the collected surface lake sediments. The content of clay minerals also showed a significant positive correlation with 137Cs activity concentration in the surface lake sediments of Koronowo Lake. A similar relationship was noticed for the OM content, but it may be suspected that it is the result of radiocesium-bearing particle accumulation in OM-rich sediments.ConclusionThe most important factor influencing the spatial distribution of 137Cs activity concentrations in the surface lake sediments of Koronowo Lake, apart from the bottom morphology and grain size of sediments, is the content of clay minerals. Moreover, the increased detrital inflow to the lake after the construction of the dam could have probably affected the vertical distribution of 137Cs activity concentrations in the bottom sediments, as evidenced by, e.g., the measurements of 40K activity concentration.

Distribution and transport of heavy metals in surface sediments of Chengbei Sea in the Bohai Sea.

It is of great significance to study the distribution characteristics and transport of heavy metals in complex sedimentary environments and areas with intensive human activities. This study analyzed sediment size, heavy metal contents (Cu, Zn, Cd, Cr, and Pb), organic carbon content, and sulfide content in surface sediments collected from 27 sites in Chengbei Sea. The main controlling factors of the distribution and transport of heavy metals were discussed from the perspective of sediment dynamics. The concentrations of Cu, Zn, Cd, Cr, and Pb in surface sediments were 7.9-20.5 mg/kg, 33.8-94.6 mg/kg, 0.08-0.26 mg/kg, 6.3-62.3 mg/kg, and 3-13.4 mg/kg, respectively. According to the geoaccumulation index, the study area was not polluted by the heavy metals, except for Cd, which did not pollute only areas with relatively coarse-grained sediments. Combining the results of correlation analysis, tidal residual current analysis, sediment transport trend analysis, and principal component analysis confirmed that Cu, Zn, and Cd originate from natural sources, and their distribution characteristics are mainly controlled by the grain size of surface sediments. Cr and Pb could be attributed to human activities, such as oil exploration, and their distribution characteristics were affected by sediment transport and tidal residual current. Zonation of the sedimentary dynamic environment also provided reference for the relationship between the distribution of heavy metals in surface sediments and sedimentary environments.

Measurement of sediment particle size distribution and shape using dynamic imaging analysis

Hydropower plants operating in fragile mountainous regions face severe sediment erosion of hydraulic turbines, resulting in decreased efficiency, frequent power interruptions, and downtime for maintenance. The sediment size and shape are detrimental to the hydraulic turbines and influence sediment erosion. Sediment management is a crucial aspect of tackling sediment erosion in hydraulic turbines. The traditional method of measuring particle size and shape is time-consuming, labour-intensive, and usually requires statistical analysis. The present study applies the recent technique of dynamic imaging analysis to determine the particle size distribution and shape of sediment. Five different silt-sand mixtures have been used to check the ability of dynamic imaging analysis. Further, the repeatability and reliability of the results were checked by carrying out five repeated measurements of each sample under the same condition in a short period of time. This study will help the researchers and sedimentologists to adopt the dynamic imaging analysis technique for measuring particle size and shape and help the instrument developer in designing a better future version of the instrument.