Patterns of grain-size temporal variation of sediment transported by overland flow associated with moving storms: interpreting soil flume experiments

Abstract. This study describes and interprets the evolution of grain-size distribution of sediment yields generated in an experimental soil flume subjected to downstream and upstream moving rain storms. Results of laboratory experiments show that downstream moving storms cause more soil loss than do upstream moving storms. The pattern of sediment grain-size evolution in time during a runoff event exhibits a clear dependence on the direction of storm movement. A strong relationship between overland flow discharge and mean sediment size is found. Nevertheless, the mean grain-size of sediments transported during the rising limb of the hydrograph is coarser than during the recession limb of the hydrograph. This is more marked for downstream moving storms.

Download Full-text

Prediction of Mean Grain Size Evolution during the Forging of IN718 Turbine Disc

MATEC Web of Conferences ◽

10.1051/matecconf/20168002012 ◽

2016 ◽

Vol 80 ◽

pp. 02012 ◽

Cited By ~ 1

Author(s):

Zhang Haiyan ◽

Zhang Shihong ◽

Cheng Ming

Keyword(s):

Grain Size ◽

Size Evolution ◽

Mean Grain Size ◽

Turbine Disc

Download Full-text

Sedimentary provinces, and associated bedforms and benthos on the Scott Reef-Rowley Shoals platform off north-west Australia

Marine and Freshwater Research ◽

10.1071/mf9880133 ◽

1988 ◽

Vol 39 (2) ◽

pp. 133 ◽

Cited By ~ 3

Author(s):

RJ McLoughlin ◽

TLO Davis ◽

TJ Ward

Keyword(s):

Grain Size ◽

Carbonate Content ◽

Sediment Type ◽

Sediment Grain Size ◽

North West ◽

Significant Relationships ◽

Sediment Types ◽

Sea Bed ◽

Mean Grain Size ◽

High Carbonate

The distribution of sediment types on the Scott Reef-Rowley Shoals platform, a marginal plateau adjoining the continental shelf of north-west Australia, has been investigated. Sediments in this region are predominately muds, with a high carbonate content. Sands, which are scarce, are mainly composed of both benthic and pelagic skeletal remains, with any gravel-sized material consisting of relict molluscan debris and, occasionally, relict coralline material. Correlation of sediment type with sea-bed characteristics as determined from photographs of the bottom at the same site showed significant relationships between mean grain size, and degree of sediment rippling and benthic activity. Similar correlations were found for the skewness measure of the analysis of sediment grain-size frequency. It is concluded that sediment type bears strong relationships with benthic activity and bedform morphology. Correlations between sediment provinces and the distribution of Australian scampi (Metanephrops sp.), a relatively new fishery in the region, are discussed.

Download Full-text

Granulometric characterization of sediments transported by surface runoff generated by moving storms

Nonlinear Processes in Geophysics ◽

10.5194/npg-15-999-2008 ◽

2008 ◽

Vol 15 (6) ◽

pp. 999-1011 ◽

Cited By ~ 11

Author(s):

J. L. M. P. de Lima ◽

C. S. Souza ◽

V. P. Singh

Keyword(s):

Grain Size ◽

Surface Runoff ◽

Laboratory Experiments ◽

Overland Flow ◽

Temporal Distribution ◽

Surface Flow ◽

Constant Speed ◽

Stream Power ◽

Sediment Grain Size ◽

Rain Simulator

Abstract. Due to the combined effect of wind and rain, the importance of storm movement to surface flow has long been recognized, at scales ranging from headwater scales to large basins. This study presents the results of laboratory experiments designed to investigate the influence of moving rainfall storms on the dynamics of sediment transport by surface runoff. Experiments were carried out, using a rain simulator and a soil flume. The movement of rainfall was generated by moving the rain simulator at a constant speed in the upstream and downstream directions along the flume. The main objective of the study was to characterize, in laboratory conditions, the distribution of sediment grain-size transported by rainfall-induced overland flow and its temporal evolution. Grain-size distribution of the eroded material is governed by the capacity of flow that transports sediments. Granulometric curves were constructed using conventional hand sieving and a laser diffraction particle size analyser (material below 0.250 mm) for overland flow and sediment deliveries collected at the flume outlet. Surface slope was set at 2%, 7% and 14%. Rainstorms were moved with a constant speed, upslope and downslope, along the flume or were kept static. The results of laboratory experiments show that storm movement, affecting the spatial and temporal distribution of rainfall, has a marked influence on the grain-size characteristics of sediments transported by overland flow. The downstream-moving rainfall storms have higher stream power than do other storm types.

Download Full-text

Universal relation with regime transition for sediment transport in fine-grained rivers

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1911225116 ◽

2019 ◽

Vol 117 (1) ◽

pp. 171-176 ◽

Cited By ~ 7

Author(s):

Hongbo Ma ◽

Jeffrey A. Nittrouer ◽

Baosheng Wu ◽

Michael P. Lamb ◽

Yuanfeng Zhang ◽

...

Keyword(s):

Grain Size ◽

Sediment Load ◽

Yellow River ◽

Fine Sand ◽

Sediment Flux ◽

Universal Relation ◽

Sediment Grain Size ◽

Fine Grained ◽

Predictive Algorithm ◽

Sediment Size

Fine-grained sediment (grain size under 2,000 μm) builds floodplains and deltas, and shapes the coastlines where much of humanity lives. However, a universal, physically based predictor of sediment flux for fine-grained rivers remains to be developed. Herein, a comprehensive sediment load database for fine-grained channels, ranging from small experimental flumes to megarivers, is used to find a predictive algorithm. Two distinct transport regimes emerge, separated by a discontinuous transition for median bed grain size within the very fine sand range (81 to 154 μm), whereby sediment flux decreases by up to 100-fold for coarser sand-bedded rivers compared to river with silt and very fine sand beds. Evidence suggests that the discontinuous change in sediment load originates from a transition of transport mode between mixed suspended bed load transport and suspension-dominated transport. Events that alter bed sediment size near the transition may significantly affect fluviocoastal morphology by drastically changing sediment flux, as shown by data from the Yellow River, China, which, over time, transitioned back and forth 3 times between states of high and low transport efficiency in response to anthropic activities.

Download Full-text

Comparative organic geochemistry of Indian margin (Arabian Sea) sediments: estuary to continental slope

Biogeosciences Discussions ◽

10.5194/bgd-11-3387-2014 ◽

2014 ◽

Vol 11 (2) ◽

pp. 3387-3422 ◽

Cited By ~ 1

Author(s):

G. Cowie ◽

S. Mowbray ◽

S. Kurian ◽

A. Sarkar ◽

C. White ◽

...

Keyword(s):

Grain Size ◽

Continental Slope ◽

Arabian Sea ◽

Organic Geochemistry ◽

Strong Relationship ◽

Sediment Grain Size ◽

Organic C ◽

Oxygen Exposure ◽

The North ◽

Upper Slope

Abstract. Surface sediments from sites across the Indian margin of the Arabian Sea were analysed for their carbon and nitrogen compositions (elemental and stable isotopic), grain size distributions and biochemical indices of organic matter (OM) source and/or degradation state. Site locations ranged from the estuaries of the Mandovi and Zuari rivers to depths of ~ 2000 m on the continental slope, thus spanning nearshore muds and sands on the shelf and both the semi-permanent oxygen minimum zone (OMZ) on the upper slope (~ 200–1300 m) and the seasonal hypoxic zone that impinges on the shelf. Source indices showed mixed marine and terrigenous OM within the estuaries, and overwhelming predominance (80%+) of marine OM on the shelf and slope. Thus, riverine OM is heavily diluted by autochthonous marine OM and/or is efficiently remineralised within or immediately offshore of the estuaries. Any terrigenous OM that is exported appears to be retained in nearshore muds; lignin phenols indicate that the small terrigenous OM content of slope sediments is of different origin, potentially from rivers to the north. Organic C contents of surface shelf and slope sediments varied from < 0.5 wt % in relict shelf sands to over 7 wt % at slope sites within the OMZ, decreasing to ≤ 1 wt % at 2000 m. Major variability (~ 5 wt %) was found at slope sites within the OMZ of similar depth and near-identical bottom-water oxygen concentration. A strong relationship between organic C and sediment grain size was seen for sediments within the OMZ, but lower C loadings were found for sites on the shelf and below the OMZ. Diagenetic indices confirmed that lower C content below the OMZ is associated with greater extent of OM degradation, but that C-poor shelf sediments are not consistently more degraded than those within the OMZ. Together, the results indicate that OM enrichment on the upper slope can be explained by physical controls (winnowing and/or dilution) on the shelf and progressive OM degradation with increasing oxygen exposure below the OMZ. Reduced oxygen exposure may contribute to OM enrichment at some sites within the OMZ, but hydrodynamic processes are the overriding control on sediment OM distribution.

Download Full-text

Characteristics of Boleng Strait Sediments, East Nusa Tenggara, and its Relationship with Current Velocity

BULLETIN OF THE MARINE GEOLOGY ◽

10.32693/bomg.33.1.2018.387 ◽

2018 ◽

Vol 33 (1) ◽

Author(s):

Hananto Kurnio ◽

Ai Yuningsih ◽

Rina Zuraida

Keyword(s):

Grain Size ◽

Current Velocity ◽

Coastal Area ◽

Coastal Sediments ◽

Medium Sand ◽

Sediment Grain Size ◽

Sediment Samples ◽

Mean Grain Size ◽

Seafloor Sediments ◽

Seafloor Sediment

Islands of Nusa Tenggara are separated by narrow and deep straits resulted from complex tectonic activties. One of the strait is Boleng Strait where tidal current as high as 310 cm/s occurred which might be suitable for an ocean current power plant. Utilization of such resources would need various information of the area, one of them is sediment textures that characterized the seafloor and coastal area and their relationship to current velocity. Grain size analyses were conducted on 12 seafloor sediment samples and 26 coastal sediment samples to identify sediment texture. An additonal 14 seafloor sediment samples with limited volume were observed to determine their sediment types. The result of analysis yielded six types of seafloor sediments: Sand, Gravelly Sand, Sandy Gravel, Silty Sand and Sandy Silt. The sediment grain size is equally influenced by current velocity (r = 0.57) and water depth (r = 0.52) which is reflected by sediment distribution: coarse–grain sediments cover the area near Boleng Strait which has stronger current and fine–grain sediments cover the inner part of the Lewoleba Bay. Plot of six sets of mean grain size and current velocity on Hjulström diagram shows that most of seafloor sediments are on the move and one (SBL. 14) is being eroded. This condition might affect the turbine and thus needs to be taken into consideration when designing the turbine. Grain size analyses on coastal sediment samples show that the mean grain size of coastal sediments ranges between 0.19 mm and 0.62 mm with average value of 0.33 mm that is classified as medium sand. Sand fraction in coastal sediments composes 57% to 100% of the sediments. Observation on mineralogy of the sediments shows abundance of magnetite that concentrates in the fine and medium sand fractions. The presence of magnetite indicate that current–related selective entrainment occurs in the study area. This condition suggests that the coastal area is also strongly affected by ocean current.Key words: current velocity, sediment grain size, Boleng Strait.Aktivitas tektonik di Nusa Tenggara Timur menyebabkan terbentuknya batimetri yang kompleks di sekitar kepulauan tersebut yang dicirikan oleh adanya selat sempit dan dalam yang memisahkan pulau–pulau. Salah satu selat tersebut adalah Selat Boleng yang memiliki kecepatan arus terukur maksimum sebesar 310 cm/s yang dapat digunakan sebagai pembangkit energi listrik. Desain turbin arus akan membutuhkan banyak informasi, salah satunya adalah sedimen dasar laut dan pantai serta hubungannya dengan kecepatan arus. Analisis besar butir dilakukan pada 12 sampel sedimen dasar laut dan 26 sampel sedime pantai untuk menentukan jenis sediment. Sebanyak 14 sampel sedimen dasar laut dengan volume terbatas diamati untuk mengetahui jenis sedimen. Hasil analisis menunjukkan bahwa sedimen dasar laut terdiri atas enam jenis: Pasir, Pasir Kerikilan, Kerikil pasiran, Pasir Lanauan dan Lanau Pasiran. Ukuran butir sedimen dipengaruhi oleh kecepatan arus (r = 0.57) dan kedalaman laut (r = 0.52) yang tercermin pada distribusi sedimen: sedimen berukuran kasar menutupi dasar laut di dekat Selat Boleng yang berarus lebih kuat, dan sedimen berukuran halus menutupi dasar laut di bagian dalam Teluk Lewoleba. Plot enam set ukuran butir rata–rata dan kecepatan arus pada diagram Hjulström menunjukkan bahwa hampir seluruh sampel berada dalam kondisi bergerak dan bahkan satu (SBL. 14) sedang mengalami erosi. Kondisi ini akan mempengaruhi turbin sehingga perlu dijadikan pertimbangan saat mendesain turbin. Hasil analisis besar butir pada sedimen pantai menunjukkan bahwa ukuran butir rata–rata sedimen pantau berkisar 0.19 mm dan 0.62 mm dengan nilai rata–rata 0.33 mm yang termasuk dalam fraksi pasir sedang. Fraksi pasir dalam sedimen pantai menyusun 57%–100% sedimen. Pengamatan mineralogi menunjukkan melimpahnya magnetit yang terkonsentrasi pada fraksi pasir halus–sedang. Keberadaan magnetit menunjukkan adanya proses pemisahan yang berkaitan dengan arus laut. Kondisi ini menunjukkan bahwa daerah pantai Selat Boleng juga dipengaruhi oleh arus laut. Kata Kunci: kecepatan arus, ukuran butir sedimen, Selat Boleng.

Download Full-text

The effect of debris-flow sediment grain size distribution on fan forming processes

10.5194/esurf-2021-69 ◽

2021 ◽

Author(s):

Haruka Tsunetaka ◽

Norifumi Hotta ◽

Yuichi Sakai ◽

Thad Wasklewicz

Keyword(s):

Grain Size ◽

Debris Flow ◽

Size Distribution ◽

Grain Size Distribution ◽

Flow Characteristics ◽

Granular Flows ◽

Spatial Diversity ◽

Flume Experiments ◽

Sediment Grain Size ◽

Average Grain Size

Abstract. Knowledge of the processes driving debris-flow fan evolution are critical in the support of efforts to mitigate related hazards, reduce risk to populations and infrastructure, and reconstruct the history of sediment dynamics in mountainous areas. Research on debris-flow fan development has focused on topographic controls, debris-flow volume and rheology, and the sequence of occurrence of debris flows. While these items have explained a great deal about fan formation and specifically avulsion and runout mechanisms, there is a need to further investigate other properties as they relate to debris-flow fan formative process. Here, we examined the role of debris-flow grain-size distribution on fan formation. Flume experiments were employed to examine the morphology of debris-flow fans that resulted from flows with mono- or multi-granular sediment composition with the same average grain size. All other flow characteristics were held constant. The mono-granular flows formed a symmetric-like fan morphology because there was little avulsion during the formation process. The multi-granular flows produced fans with an asymmetric morphology. Avulsions occurred on both lateral extents of the fan during the early stages of fan development and caused the runout direction to shift produce the fan asymmetry. Grain-size distribution was closely related to spatial diversity in fan morphology and stratigraphy.

Download Full-text

Variability of suspended sediment grain size distribution in winter floods

Annals of Warsaw University of Life Sciences – SGGW Land Reclamation ◽

10.1515/sggw-2016-0011 ◽

2016 ◽

Vol 48 (2) ◽

pp. 141-151

Author(s):

Agnieszka Hejduk ◽

Leszek Hejduk

Keyword(s):

Particle Size ◽

Grain Size ◽

Standard Deviation ◽

Size Distribution ◽

Suspended Sediment ◽

Grain Size Distribution ◽

Sediment Grain Size ◽

Mean Values ◽

Average Value ◽

Sediment Size

Abstract Variability of suspended sediment grain size distribution in winter floods. The work presents the results of research concern variability of suspended sediment grain size, transported during the winter floods in agricultural catchment, in the period of hydrological years 2012-2015. The information about grain size distribution from nine winter flood events were collected over the study period, which allowed to analyze the variability of suspended sediment particle size during the various events. Grain size of sediment was determined using a laser particle size analyzer Mastersizer Microplus from Malvern Instruments Ltd. Variability of individual particle size classes were observed in each flood. Sand fraction dominated in seven of nine measured events. There was no significant increase of suspended sediment size in relation to the maximum of discharge. It can be explain by a relatively low discharge of recorded events. The percentage of material classified as clay (<4 μm) ranged from 0.08 to 1.01%, silt-sized material (>4 and <63 μm) ranged between 9.31 and 67.17% and sand-size material (>63 μm) ranged from 32.01 to 90.61%. The relationship between the particle size and the discharge requires further studies. The diameter d10, d50 and d90 and a standard deviation were calculated for each flood. Mean values of d50 for individual flood ranged between 41.05 and 191.32 μm with average value of 99.01 μm and average standard deviation of 32.57.

Download Full-text

Small-Scale Morpho-Sedimentary Dynamics in the Swash Zone of a Megatidal Mixed Sand–Gravel Beach

Journal of Marine Science and Engineering ◽

10.3390/jmse9040413 ◽

2021 ◽

Vol 9 (4) ◽

pp. 413

Author(s):

Tristan B. Guest ◽

Alex E. Hay

Keyword(s):

Remote Sensing ◽

Grain Size ◽

Coarse Grained ◽

Small Scale ◽

Swash Zone ◽

Sediment Grain Size ◽

Mean Grain Size ◽

Sedimentary Dynamics ◽

Gravel Beaches ◽

Gravel Beach

On mixed sand–gravel beaches, impacts from gravel- and cobble-sized grains—mobilized by the energetic shorebreak—limit the utility of in situ instrumentation for measuring the small-scale response of the beach face on wave period time scales. We present field observations of swash zone morpho-sedimentary dynamics at a steep, megatidal mixed sand–gravel beach using aeroacoustic and optical remote sensing. Coincident observations of bed level and mean surficial sediment grain size in the swash zone were obtained using an array of optical cameras paired with acoustic range sensors. Lagrangian tracking of swash-transported cobbles was carried out using an additional downward-oriented camera. The principal objective of the study was to investigate linkages between sediment grain size dynamics and swash zone morphological change. In general, data from the range sensor and camera array show that increases in bed level corresponded to increases in mean grain size. Finer-scale structures in the bed level and mean grain size signals were observable over timescales of minutes, including signatures of bands of coarse-grained material that migrated shoreward with the leading edge of the swash prior to high tide berm formation. The direction and magnitude of cobble transport in the swash varied with cross-shore position, and with the composition of the underlying bed. These results demonstrate that close-range remote sensing techniques can provide valuable insights into the roles of cobble-sized versus sand-sized particle dynamics in the swash zone on mixed sand–gravel beaches.

Download Full-text

Characterizing the Relationship between the Sediment Grain Size and the Shoreline Variability Defined from Sentinel-2 Derived Shorelines

Remote Sensing ◽

10.3390/rs13142829 ◽

2021 ◽

Vol 13 (14) ◽

pp. 2829

Author(s):

Carlos Cabezas-Rabadán ◽

Josep E. Pardo-Pascual ◽

Jesus Palomar-Vázquez

Keyword(s):

Grain Size ◽

Remote Sensing Data ◽

Western Mediterranean ◽

Fundamental Parameter ◽

Numerical Function ◽

Sediment Grain Size ◽

Sediment Size ◽

Definition Of ◽

The Relationship ◽

Sentinel 2

Sediment grain size is a fundamental parameter conditioning beach-face morphology and shoreline changes. From remote sensing data, an efficient definition of the shoreline position as the water–land interface may allow studying the geomorphological characteristics of the beaches. In this work, shoreline variability is defined by extracting a set of Satellite Derived Shorelines (SDS) covering about three and a half years. SDS are defined from Sentinel 2 imagery with high accuracy (about 3 m RMSE) using SHOREX. The variability is related to a large dataset of grain-size samples from the micro-tidal beaches at the Gulf of Valencia (Western Mediterranean). Both parameters present an inverse and non-linear relationship probably controlled by the beach-face slope. High shoreline variability appears associated with fine sands, followed by a rapid decrease (shifting point about medium/coarse sand) and subsequent small depletions as grain sizes increases. The relationship between both parameters is accurately described by a numerical function (R2 about 0.70) when considering samples at 137 open beaches. The definition of the variability is addressed employing different proxies, coastal segment lengths, and quantity of SDS under diverse oceanographic conditions, allowing to examine the effect they have on the relation with the sediment size. The relationship explored in this work improves the understanding of the mutual connection between sediment size, beach-face slope, and shoreline variability, and it may set up the basis for a rough estimation of sediment grain size from satellite optical imagery.

Download Full-text