Modelling Erosion and Deposition of Cohesive Sediments from Hay River, Northwest Territories, Canada

A large volume sample of river-bed cohesive sediment and water from Hay River, Northwest Territories, Canada was collected during a spring field program in 2000 as part of a study on under-ice movement of sediment just before breakup. Controlled laboratory experiments were subsequently conducted on the Hay River water/sediments in a rotating annular flume at Burlington, Ontario, Canada to better understand the deposition and erosion processes of cohesive sediment transport. The deposition experiments in the rotating flume confirmed that the Hay River sediment is cohesive and the critical shear stress for deposition and the rates of deposition are a function of bed shear stress and the initial concentration of the sediment in suspension. The erosion experiments provided quantitative data on the critical shear stress for erosion and the rates of erosion as a function of bed shear stress and the age of the sediment deposit. The erosion experiments also indicated that the growth of the biofilm had an influence on the erosion characteristics of the Hay River sediment. Based on the data from the rotating circular flume experiments, a modelling strategy is proposed for calculating the under-ice transport of the cohesive sediments in the Hay River.

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The effect of coarse gravel on cohesive sediment entrapment in an annular flume

Proceedings of the International Association of Hydrological Sciences ◽

10.5194/piahs-367-157-2015 ◽

2015 ◽

Vol 367 ◽

pp. 157-162 ◽

Cited By ~ 1

Author(s):

K. Glasbergen ◽

M. Stone ◽

B. Krishnappan ◽

J. Dixon ◽

U. Silins

Keyword(s):

Shear Stress ◽

Hyporheic Zone ◽

Critical Shear Stress ◽

Cohesive Sediment ◽

Shear Stresses ◽

Cohesive Sediments ◽

Gravel Bed ◽

Gravel Beds ◽

Annular Flume ◽

Surface And Pore Water

Abstract. While cohesive sediment generally represents a small fraction (<0.5%) of the total sediment mass stored in gravel-bed rivers, it can strongly influence physical and biogeochemical processes in the hyporheic zone and alter aquatic habitat. This research was conducted to examine mechanisms governing the interaction of cohesive sediments with gravel beds in the Elbow River, Alberta, Canada. A series of erosion and deposition experiments with and without a gravel bed were conducted in a 5-m diameter annular flume. The critical shear stress for deposition and erosion of cohesive sediment without gravel was 0.115 Pa and 0.212 Pa, respectively. In experiments with a gravel bed, cohesive sediment moved from the water column into the gravel bed via the coupling of surface and pore water flow. Once in the gravel bed, cohesive sediments were not mobilized under the maximum applied shear stresses (1.11 Pa) used in the experiment. The gravel bed had an entrapment coefficient (ratio between the entrapment flux and the settling flux) of 0.2. Accordingly, when flow conditions are sufficient to produce a shear stress that will mobilize the armour layer of the gravel bed (>16 Pa), cohesive materials trapped within the gravel bed will be entrained and transported into the Glenmore Reservoir, where sediment-associated nutrients may pose treatment challenges to the drinking water supply.

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Relationship between bed shear stress and suspended sediment concentration: annular flume experiments

International Journal of Sediment Research ◽

10.1016/s1001-6279(12)60009-2 ◽

2011 ◽

Vol 26 (4) ◽

pp. 513-523 ◽

Cited By ~ 12

Author(s):

Yunwei WANG ◽

Qian YU ◽

Shu GAO

Keyword(s):

Shear Stress ◽

Suspended Sediment ◽

Suspended Sediment Concentration ◽

Sediment Concentration ◽

Bed Shear Stress ◽

Flume Experiments ◽

Annular Flume

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Experimental Investigation of Erosion Characteristics of Fine-Grained Cohesive Sediments

Water ◽

10.3390/w12051511 ◽

2020 ◽

Vol 12 (5) ◽

pp. 1511

Author(s):

Bommanna Gounder Krishnappan ◽

Mike Stone ◽

Steven Granger ◽

Hari Upadhayay ◽

Qiang Tang ◽

...

Keyword(s):

Experimental Data ◽

Shear Stress ◽

Critical Shear Stress ◽

River System ◽

Cohesive Sediment ◽

Erosion Process ◽

Fine Grained ◽

Annular Flume ◽

Two Factors ◽

Sediment Deposit

In this short communication, the erosion process of the fine, cohesive sediment collected from the upper River Taw in South West England was studied in a rotating annular flume located in the National Water Research Institute in Burlington, Ontario, Canada. This study is part of a research project that is underway to model the transport of fine sediment and the associated nutrients in that river system. The erosion experimental data show that the critical shear stress for erosion of the upper River Taw sediment is about 0.09 Pa and it did not depend on the age of sediment deposit. The eroded sediment was transported in a flocculated form and the agent of flocculation for the upper River Taw sediment may be due to the presence of fibrils from microorganisms and organic material in the system. The experimental data were analysed using a curve fitting approach of Krone and a mathematical model of cohesive sediment transport in rotating circular flumes developed by Krishnappan. The modelled and measured data were in good agreement. An evaluation of the physical significance of Krone’s fitting coefficients is presented. Variability of the fitting coefficients as a function of bed shear stress and age of sediment deposit indicate the key role these two factors play in the erosion process of fluvial cohesive sediment.

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RESUSPENSION OF DEPOSITED COHESIVE SEDIMENT BEDS

Coastal Engineering Proceedings ◽

10.9753/icce.v18.95 ◽

1982 ◽

Vol 1 (18) ◽

pp. 95 ◽

Cited By ~ 7

Author(s):

Ashish J. Mehta ◽

Emmanuel Partheniades

Keyword(s):

Shear Stress ◽

Shear Strength ◽

Critical Shear Stress ◽

Cohesive Sediment ◽

Significant Feature ◽

Bed Shear Stress ◽

Laboratory Investigations ◽

Shear Stength ◽

The Difference ◽

Consolidation Time

Surfieial layers of estuarial fine, cohesive sediment beds are deposited from flow and often are in a state of partial consolidation. A series of laboratory investigations were carried out to elucidate the erosional behavior of deposited cohesive sediment beds in flumes using kaolinite. A significant feature of such beds is that they are stratified with respect to the density and the cohesive shear stength. Under a given bed shear stress, erosion occurs at a continuously decreasing rate up to a depth at which the bed shear stress equals the shear strength. This bed shear stress is therefore also equal to the critical shear stress for erosion at that depth. An expression for the rate of erosion relating this rate to the difference between the bed shear stress and the critical shear stress has been obtained. The critical shear stress increases both with depth and with the bed consolidation time. The rate of erosion decreases with increasing consolidation time.

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Fractal dimensions of cohesive sediment during settling in steady state flow with different initial sediment concentrations

Canadian Journal of Civil Engineering ◽

10.1139/l05-011 ◽

2005 ◽

Vol 32 (4) ◽

pp. 658-664 ◽

Cited By ~ 2

Author(s):

M Stone ◽

B G Krishnappan

Keyword(s):

Shear Stress ◽

Steady State ◽

Suspended Solids ◽

Fractal Dimensions ◽

Sediment Concentration ◽

Cohesive Sediment ◽

Image Analysis System ◽

Bed Shear Stress ◽

Annular Flume ◽

Over Time

Morphology of particle populations of cohesive sediment were examined during settling experiments in an annular flume with different initial sediment concentrations (200 and 350 mg/L) at constant bed shear stress (0.121 N/m2) using fractal dimensions. The area, longest axis, and perimeter of suspended solids were measured with light microscopy and an image-analysis system to determine three fractal dimensions (D, D1, D2). The ratio between the initial and steady state (time T = 300 min) sediment concentration was 0.54 for both experimental runs and is a function of bed shear stress, not the initial sediment concentration. The fractal dimension D changed from 1.32 at the start of the experiment to 1.36 at steady state, which represents an increase in shape irregularity of larger particles over time compared with smaller particles. At steady state, D1 and D2 were 1.19 and 1.66, respectively. Small increases in D1 and D2 over time indicated a change in morphology towards longer and more elongated particles. The D2 measurements in the present study indicate that differential sedimentation is the predominant flocculation mechanism of cohesive sediments in the flume settling experiments. Fractal dimensions of suspended solids were not significantly different at steady state as a function of initial sediment concentration.Key words: particle morphology, fractal dimensions, cohesive sediment, flocculation, deposition, annular flume.

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PROBABILITY OF EXCEEDING THE CRITICAL SHEAR STRESS FOR SAND MOTION IN SPECIFIC WAVE AND CURRENT CONDITIONS

Coastal Engineering Proceedings ◽

10.9753/icce.v33.sediment.4 ◽

2012 ◽

Vol 1 (33) ◽

pp. 4

Author(s):

Pierre-Yves Henry ◽

Alf Tørum ◽

Øivind Artsen ◽

Dag Myrhaug ◽

Muk Chen Ong

Keyword(s):

Shear Stress ◽

Critical Shear Stress ◽

Bed Shear Stress ◽

Random Waves ◽

Flow Conditions ◽

Flume Experiments ◽

Natural Sand ◽

Waves And Currents ◽

Mobility Parameter ◽

A Current

This study is focusing on the threshold of sand motion under random waves combined with a following current. The analysis is based on some flume experiments realized over a natural sand bed for different flow conditions (waves and currents). The main result comes as a map of the probability to exceed the threshold of sand motion, as a function of a wave and a current mobility parameter. These observations are compared to methods predicting the bed shear stress using an equivalent monochromatic wave, and links between the probability of exceeding the critical shear stress for initiation of sand motion and the calculated maximum bed shear stress are found.

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Measuring the onset of mine tailings erosion

Canadian Geotechnical Journal ◽

10.1139/t06-116 ◽

2007 ◽

Vol 44 (4) ◽

pp. 473-489 ◽

Cited By ~ 4

Author(s):

M Haneef-Mian ◽

Ernest K Yanful ◽

Robert Martinuzzi

Keyword(s):

Shear Stress ◽

Power Law ◽

Mine Tailings ◽

Laser Doppler Anemometry ◽

Critical Shear Stress ◽

Laser Doppler ◽

Shear Stresses ◽

Cohesive Sediments ◽

Fine Grained ◽

Power Law Equation

The present study gives details of a methodology for estimating the critical shear stress for erosion of mine tailings and other naturally occurring cohesive sediments. Erosion of a cohesive sediments bed occurs when the critical shear stress is exceeded to break the interparticle bond. Experiments were conducted in a 30 cm diameter laboratory column and calibrated using laser Doppler anemometry. The results showed that the erosion pattern of mine tailings particles was similar to those of fine-grained cohesive sediments. A power-law relation of the form E = α[(τ – τcr)/τcr]n is suggested for mine tailings, where E is the erosion rate, α is a coefficient, τ is the shear stress, τcr is the critical shear stress, and n is an exponent. The computed values of α, n, and τcr in the power-law equation were found to be comparable to values derived from experiments in a rotating circular flume. The derived expression for rate of erosion may be incorporated in resuspension and transport models for fine mine tailings of a similar nature.Key words: mine tailings, laser Doppler velocimetry, wall shear stresses, critical shear stress for erosion, erosion – shear stress relationship.

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Bed Shear Stress Influence on Local Scour Geometry Properties in Various Flume Development Conditions

Water ◽

10.3390/w11112346 ◽

2019 ◽

Vol 11 (11) ◽

pp. 2346 ◽

Cited By ~ 3

Author(s):

Kiraga ◽

Popek

Keyword(s):

Shear Stress ◽

Sediment Transport ◽

Mutual Influence ◽

Three Dimensional ◽

Critical Shear Stress ◽

Water Structure ◽

Correlation Coefficients ◽

Bed Shear Stress ◽

Hole Dimensions ◽

Bed Material

Numerous approaches in sediment mobility studies highlighted the key meaning of channel roughness, which results not only from bed material granulation but also from various bed forms presence, caused by continuous sediment transport. Those forms are strictly connected with the intensity of particle transport, and they eventuate from bed shear stress. The present paper comprised of local scours geometric dimensions research in three variants of lengthwise development of laboratory flume in various hydraulic properties, both in “clear-water” and “live-bed” conditions of sediment movement. Lots of measurements of the bed conformation were executed using the LiDAR device, marked by a very precise three-dimensional shape description. The influence of the bed shear stress downstream model on scours hole dimensions of water structure was investigated as one of the key factors that impact the sediment transport intensity. A significant database of 39 experimental series, lasting averagely 8 hours, was a foundation for delineating functional correlations between bed shear stress-and-critical shear stress ratio and geometry properties of local scours in various flume development cases. In the scope of mutual influence of bed shear stress and water depth, high correlation coefficients were attained, indicating very good and good functional correlations. Also, the influence of bed shear stress and the total length of the scour demonstrated a high correlation coefficient.

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