International Journal of Sediment Research
Volume35, Issue 2
Pages115-225 (April 2020)
1. Uniform and graded bed-load sediment transport in a degrading
channel with non-equilibrium conditions
Khabat KHOSRAVI, Amir H.N. CHEGINI, James R. COOPER, Prasad
DAGGUPATI, Andrew BINNS, Luca MAO
Pages 115-124
2. Incipient sediment motion based on turbulent fluctuations
Wan Hanna Melini WAN MOHTAR; Ji Wang LEE; Najwa Izzaty MOHAMMAD AZHA;
Nian-Sheng CHENG
Pages 125-133
3. Solute mixing in a permeable non-rectangular channel
Sonia; ZEBARDAST; Sayyed-Hassan; TABATABAEI；Fariborz ABBASI;·Manuchehr HEIDARPOUR
Pages 134-145
4. Influence of external loading and halocline on phosphorus release
from sediment in an artificial tidal lake
Yong-Hoon JEONG; Dong-Heui KWAK
Pages 146-156
5. Combination of sensitivity and uncertainty analyses for
sediment transport modeling in sewer pipes
Isa EBTEHAJ; Hossein BONAKDARI; · Mir Jafar Sadegh SAFARI; Bahram
GHARABAGHI; Amir Hossein ZAJI; Hossien RIAHI MADAVAR; Zohreh SHEIKH KHOZANI; Mohammad
Sadegh ES-HAGHI; Aydin SHISHEGARAN; Ali DANANDEH MEHR
Pages 157-170
6. Evaluation of the parameters affecting the roughness coeffi
cient of sewer pipes with rigid and loose boundary conditions via kernel based
approaches
Kiyoumars ROUSHANGAR； Roghayeh GHASEMPOUR； Sanam BIUKAGHAZADEH
Pages 171-179
7. Impact of anthropogenic activities on the sediment microbial
communities of Baiyangdian shallow lake
Wenjun WANG; YUJUNYI ; Yufeng YANG; Yang ZHOU; Shanghong ZHANG;
Xuan WANG; Zhifeng YANG
Pages 180-192
8. Experimental investigation on local shear stress and
turbulence intensities over a rough non-uniform bed with and without sediment
using 2D particle image velocimetry
Petr LICHTNEGER; Christine SINDELAR; Johannes SCHOBESBERGER;
Christoph HAUER; Helmut HABERSACK
Pages 193-202
9. Numerical simulation of hydrodynamic characteristics and
bedload transport in cross sections of two gravel-bed rivers based on
one-dimensional lateral distribution method
Chien PHAM VAN; Vivien CHUA
Pages 203-216
10. Laboratory measurements of the fall velocity of fi ne
sediment in an estuarine environment
Jiaqi YANG; Limo TANG; Yuntong SHE; Jiao SUN
Pages 217-226
===========================================
1.
Khabat KHOSRAVI, Amir
H.N. CHEGINI, James R. COOPER, Prasad DAGGUPATI, Andrew BINNS, Luca MAO
Uniform and graded bed-load sediment transport in a degrading
channel with non-equilibrium conditions
Volume
35, Issue 2, 2020
Pages 115-124
ISSN
1001-6279
https://doi.org/10.1016/j.ijsrc.2019.10.005
https://www.sciencedirect.com/science/article/pii/S1001627918302750
Abstract
Bed-load transport plays a critical role in river morphological
change and has an important impact on river ecology. Although there is good
understanding of the role of the variation of river bed grain size on transport
dynamics in equilibrium conditions, much less is understood for non-equilibrium
conditions when the channel is either aggrading or degrading. In particular,
the relative role of different grain sizes in the promotion and hindering of
the transport of coarse and fine fractions in a degrading channel has yet to be
investigated. The current study attempts to provide new understanding through a
series of flume experiments done using uniform and graded sediment particles.
The experiments revealed coarser grain-size fractions for a poorly-sorted sediment,
relative to uniform-sized sediment, reduced the transport of finer grains and
finer fractions enhanced the transport of coarse grains. This
hindering-promotion effect, caused by relative hiding and exposure of finer and
coarse fractions, increased with bed slope and decreased with relative
submergence. In particular, as relative submergence increased, the graded
fractions tended towards behaving more like their uniform-sized counterparts.
Also, the bed-load parameter of the graded fractions increased more with a rise
in bed slope than observed for the uniform-sized counterparts. These results
revealed, for degrading channel conditions, such as downstream of a dam,
bed-load equations developed for uniform bed sediment are inappropriate for use
in natural river systems, particularly in mountain streams. Furthermore,
changes in river bed composition due to activities that enhance the input of
hill-slope sediment, such as fire, logging, and agricultural development, are
likely to cause significant changes in river morphology.
Keywords
Graded sediment; Exposure; Hiding; Flume experiments;
Non-equilibrium
2.
Wan Hanna Melini WAN MOHTAR;
Ji Wang LEE; Najwa Izzaty MOHAMMAD AZHA; Nian-Sheng CHENG
Incipient sediment motion based on turbulent fluctuations
Volume 35, Issue 2, 2020
Pages 125-133
ISSN
1001-6279
https://doi.org/10.1016/j.ijsrc.2019.10.008
https://www.sciencedirect.com/science/article/pii/S1001627918303457
Abstract
The current study modifies the representation of the Shields
parameter using turbulent strength, i.e. the root-mean-square (rms) fluid
velocity. Experiments were done under a steady, uniform flow using eight
sediment sizes with particle Reynolds numbersRep ranging between 1.0 (fine
sediment) and 183.4 (coarse sediment). Utilising the peak rms horizontal
values, the critical Shields parameter was calculated and a trend similar to
the well-established Shields curve was developed. The analysis was extended to
the Shields curve obtained based on the critical shear velocity, Reynolds shear
stress, and data extracted from the oscillating grid-turbulence experiments.
Results show that turbulent fluctuations are crucial for the incipient sediment
motion and are essentially better predictors than the commonly used critical
shear velocity. A quadrant analysis to identify the role of turbulent bursting
events in incipient sediment motion also was done where sweeps and ejections
are dominant for finer and coarser sediment sizes, respectively.
Keywords
Incipient sediment motion; Root-mean-square fluid velocity;
Grid-turbulence; Quadrant analysis; Turbulent fluctuations
3.
Sonia; ZEBARDAST;
Sayyed-Hassan; TABATABAEI · Fariborz ABBASI;·Manuchehr HEIDARPOUR
Solute mixing in a permeable non-rectangular channel
Volume
35, Issue 2, 2020
Pages 134-145
ISSN
1001-6279
https://doi.org/10.1016/j.ijsrc.2019.10.007
https://www.sciencedirect.com/science/article/pii/S1001627918303275
Abstract
Understanding diffusion and solute transport, is regarded as a
main activity in environmental management, sustainable development and
sedimentation processes because of their role in diffusion of contaminants. The
current paper presents an experimental study which was done in a parabolic
channel with permeable and impermeable bed conditions in order to estimate the
transverse mixing coefficient (TMC) and the maximum solute mixing length (SML)
for different channel bed roughness coefficients and discharges. The cross section
of the channel was 0.5 m wide and 0.3 m deep with a parabolic shape
(i.e. similar to furrow irrigation). Three levels of bed roughness coefficient
of 0.02, 0.04, and 0.06, and three discharges of 5, 10, and 15 L/s were
considered. Bed infiltration channel was applied at a low level and medium
level as well as a case without infiltration. In the current experiments,
sodium chloride was used as a soluble tracer and was injected into the water at
mid depth in the upstream cross section. The tracer concentration profile in
the water and velocity profile were measured at eight cross sections in the
channel. The results showed that the values of SML ranged between 20 and 46 m
in impermeable and permeable beds channel beds respectively. The assessment of
usual discharge values, infiltration, and roughness coefficient of a furrow
(agricultural field) indicated that the SML of the furrows were less than 20 m.
In the current research, the average dimensionless mixing coefficient was found
to be 0.17 in the nonrectangular channel. Eventually, equations were developed
to explain the TMC and SML in a permeable parabolic channel that could be
beneficial in prediction of fertilizer transport in furrow irrigation.
Keywords
Environmental hydraulics; Fertigation; Furrow irrigation; Solute
mixing length; Transverse mixing coefficient
4.
Yong-Hoon JEONG; Dong-Heui
KWAK
Influence of external loading and halocline on phosphorus
release from sediment in an artifi cial tidal lake
Volume
35, Issue 2, 2020
Pages 146-156
ISSN
1001-6279
https://doi.org/10.1016/j.ijsrc.2019.10.001
https://www.sciencedirect.com/science/article/pii/S1001627918303846
Abstract
Many of the dams built in estuaries in the last century have
difficulty with water quality management. Numerous factors have affected the
estuary lake water, most importantly external loadings, tidal currents, and
increases in the phosphorus (P) release from sediment, so that most water
quality characteristics in the estuary are highly interactive and dynamic. In
the current study, water quality measurements were made in the laboratory and
field, and a series of phosphorus release experiments was done to understand
the behavior of P in an estuary lake. The concentrations of chemical oxygen
demand (COD), chlorophyll-a (Chl-a), and total P (TP) showed an
increasing trend when the pollutant loading of the influent stream water was
high. The measurements showed increasing trends, which indicates the
constituents are produced in the internal environment of the lake. When a large
amount of freshwater flowed in from the upper watershed, density stratification
was observed, which forms strongly because of the salinity of seawater. During
the period of stratification, a hypoxic layer formed, which can accelerate P
release. Comparing the open and closed conditions of the release experiments,
the P release rate was much higher under the closed condition than under the
open condition. The maximum P release rates from the sediment collected from
the five main sites of the lake were more than 2.5 times the P loading from the
inflowing streams in April. Spatially, the release rate was higher
mid-reservoir than down-reservoir where a halocline was evident. The pollutant
load discharged from the tributary watershed was deposited on the bottom
mid-reservoir, whereas it was washed out down-reservoir because of the density
stratification and strong tide in that area. To sustainably manage water
quality and decrease lake eutrophication in brackish environments formed by
freshwater from streams mixing with seawater entering through sluice dikes,
different measures than those applied in strictly freshwater environments are
required. Considering the spatial characteristics of an estuary lake, these
measures include 1) blocking settle able particles discharged from the rivers
upstream, 2) controlling hypoxia to avoid P release from the sediment and
inhibiting algae growth mid-reservoir, and 3) decreasing stratification caused
by the halocline down-reservoir.
Keywords
Estuary; Halocline; Phosphorus release; Reservoir; Sediment;
Stratification
5.
Isa EBTEHAJ; Hossein
BONAKDARI; · Mir Jafar Sadegh SAFARI; Bahram GHARABAGHI; Amir Hossein ZAJI;
Hossien RIAHI MADAVAR; Zohreh SHEIKH KHOZANI; Mohammad Sadegh ES-HAGHI; Aydin
SHISHEGARAN; Ali DANANDEH MEHR
Combination of sensitivity and uncertainty analyses for sediment
transport modeling in sewer pipes
Volume
35, Issue 2, 2020
Pages 157-170
ISSN
1001-6279
https://doi.org/10.1016/j.ijsrc.2019.08.005
https://www.sciencedirect.com/science/article/pii/S1001627918303810
Abstract
Mitigation of sediment deposition in lined open channels is an
essential issue in hydraulic engineering practice. Hence, the limiting velocity
should be determined to keep the channel bottom clean from sediment deposits.
Recently, sediment transport modeling using various artificial intelligence
(AI) techniques has attracted the interest of many researchers. The current
integrated study highlights unique insight for modeling of sediment transport
in sewer and urban drainage systems. A novel methodology based on the
combination of sensitivity and uncertainty analyses with a machine learning
technique is proposed as a tool for selection of the best input combination for
modeling process at non-deposition conditions of sediment transport. Utilizing
one to seven dimensionless parameters, 127 models are developed in the current
study. In order to evaluate the different parameter combinations and select the
training and testing data, four strategies are considered. Considering the
densimetric Froude number (Fr) as the dependent parameter, a model with
independent parameters of volumetric sediment concentration (CV)
and relative particle size (d/R) gave the best results with a mean
absolute relative error (MARE) of 0.1 and a root means square error (RMSE)
of 0.67. Uncertainty analysis is applied with a machine learning technique to
investigate the credibility of the proposed methods. The percentage of the
observed sample data bracketed by 95% predicted uncertainty bound (95PPU) is
computed to assess the uncertainty of the best models.
Keywords
Non-deposition; Sediment transport; Sensitivity analysis; Sewer;
Uncertainty analysis; Urban drainage
6.
Kiyoumars ROUSHANGAR； Roghayeh GHASEMPOUR； Sanam BIUKAGHAZADEH
Evaluation of the parameters affecting the roughness coeffi
cient of sewer pipes with rigid and loose boundary conditions via kernel based
approaches
Volume
35, Issue 2, 2020
Pages 171-179
ISSN
1001-6279
https://doi.org/10.1016/j.ijsrc.2019.08.004
https://www.sciencedirect.com/science/article/pii/S1001627919300344
Abstract
One of the important issues in water transport and sewer systems
is determining the flow resistance and roughness coefficient. An accurate
estimation of the roughness coefficient is a substantial issue in the design
and operation of hydraulic structures such as sewer pipes, the calculation of
water depth and flow velocity, and the accurate characterization of energy
losses. The current study, applies two kernel based approaches [Support Vector
Machine (SVM) and Gaussian Process Regression (GPR)] to develop roughness
coefficient models for sewer pipes. In the modeling process, two types of sewer
bed conditions were considered: loose bed and rigid bed. In order to develop
the models, different input combinations were considered under three scenarios
(Scenario 1: based on hydraulic characteristics, Scenarios 2 and 3: based on
hydraulic and sediment characteristics with and without considering sediment
concentration as input). The results proved the capability of the kernel based
approaches in prediction of the roughness coefficient and it was found that for
prediction of this parameter in sewer pipes Scenario 3 performed better than
Scenarios 1 and 2. Also, the sensitivity analysis results showed that Dgr
(Dimensionless particle number) for a rigid bed and wb/y (ratio of
deposited bed width, wb, to flow depth, y) for a loose bed had the
most significant impact on the modeling process.
Keywords
Gaussian process regression; Loose bed;Rigid bed;Roughness
coefficient;Sewer pipes;Support vector machine
7.
Wenjun WANG; YUJUNYI ;
Yufeng YANG; Yang ZHOU; Shanghong ZHANG; Xuan WANG; Zhifeng YANG
Impact of anthropogenic activities on the sediment microbial
communities of Baiyangdian shallow lake
Volume
35, Issue 2, 2020
Pages 180-192
ISSN
1001-6279
https://doi.org/10.1016/j.ijsrc.2019.10.006
https://www.sciencedirect.com/science/article/pii/S1001627919300356
Abstract
Microorganisms are recognized as sensors of external disturbance
in freshwater ecosystems. In this study, sediment samples from regions with
strong human activity interference (four sites), moderate human activity
interference (five sites) and minor human activity interference (five sites) in
Baiyangdian Lake were collected; and their physiological and chemical
properties and heavy metals contents were analyzed. The structures of bacterial
and fungal communities were tested using 16S ribosomal Ribonucleic Acid (rRNA)
and Internal Transcribed Spacer 2 (ITS2) high-throughput sequencing
technologies. The results indicated that Proteobacteria was the most abundant
bacterial phylum. Ascomycota, Basidiomycota and Ciliophora were the dominant
phyla of fungi. Obvious differences of microbial genera among the three regions
were observed, especially fungal genera. With intensified disturbance by human
activities, the Simpson and Shannon indices of bacteria significantly
decreased. The fungal communities were clustered into three groups in
accordance with the different human disturbance levels. The bacterial
communities of sediment samples under moderate and minor human disturbance
appeared similar, but different from those under strong human disturbance.
Redundancy analysis indicated that zinc, total phosphorus, copper, and lead
were the dominant factors that influenced the bacterial community. Nitrifiers
and sulfate-reducing bacteria were influenced by pH, nitrate (NO3?),
and total nitrogen. The fungal community was significantly affected by total
phosphorus. This study reveals that sediment microbial community structures
among different regions of a shallow lake are mainly impacted by human
activities.
Keywords
Bacterial community; Fungal community; Human activity
interference;
Environmental factors
8.
Petr LICHTNEGER; Christine
SINDELAR; Johannes SCHOBESBERGER; Christoph HAUER; Helmut HABERSACK
Experimental investigation on local shear stress and turbulence
intensities over a rough non-uniform bed with and without sediment using 2D particle
image velocimetry
Volume
35, Issue 2, 2020
Pages 193-202
ISSN
1001-6279
https://doi.org/10.1016/j.ijsrc.2019.11.001
https://www.sciencedirect.com/science/article/pii/S1001627919302963
Abstract
The current work focuses on locally resolving velocities,
turbulence, and shear stresses over a rough bed with locally non-uniform
character. A nonporous subsurface layer and fixed interfacial sublayer of
gravel and sand were water-worked to a nature-like bed form and additionally
sealed in a hydraulic flume. Two-dimensional Particle Image Velocimetry
(2D-PIV) was applied in the vertical plane of the experimental flume axis. Runs
with clear water and weak sediment transport were done under slightly
supercritical flow to ensure sediment transport conditions without formation of
considerable sediment deposits or dunes. The study design included analyzing
the double-averaged flow parameters of the entire measurement domain and
investigating the flow development at 14 consecutive vertical subsections.
Local geometrical variabilities as well the presence of sediment were mainly
reflected in the vertical velocity component. Whereas the vertical velocity
decreased over the entire depth in presence of sediment transport, the
streamwise velocity profile was reduced only within the interfacial sublayer.
In the region with decelerating flow conditions, however, the streamwise
velocity profile systematically increased along the entire depth extent. The
increase in the main velocity (reduction of flow resistance) correlated with a
decrease of the turbulent shear and main normal stresses. Therefore, effects of
rough bed smoothening and drag force reduction were experimentally documented
within the interfacial sublayer due to mobile sediment. Moreover, the current
study leads to the conclusion that in non-uniform flows the maximum Reynolds
stress values are a better predictor for the bed shear stress than the linearly
extrapolated Reynolds stress profile. This is an important finding because, in
natural flows, uniform conditions are rare.
Keywords
Turbulence measurement; Local bed shear stress; Sediment
transport and flow interaction; Hydraulic flume experiment; Particle image
velocimetry
9.
Chien PHAM VAN; Vivien CHUA
Numerical simulation of hydrodynamic characteristics and bedload
transport in cross sections of two gravel-bed rivers based on one-dimensional
lateral distribution method
Volume
35, Issue 2, 2020
Pages 203-216
ISSN
1001-6279
https://doi.org/10.1016/j.ijsrc.2019.12.001
https://www.sciencedirect.com/science/article/pii/S1001627919303038
Abstract
Accurate evaluation and prediction of bedload transport are
crucial in studies of fluvial hydrodynamic characteristics and river
morphology. This paper presents a one-dimensional numerical model based on the
one-dimensional lateral distribution method (1D-LDM) and six classic bedload
transport formulae that can be used to simulate hydrodynamic characteristics
and bedload transport discharge in cross sections. Two gravel-bed rivers, i.e.
the Danube River located approximately 70 km downstream from Bratislava in
Slovakia and the Toltén River in south of Chile are used as examples. In the
1D-LDM, gravity, bed shear stress, turbulent diffusion, and secondary flow are
included to allow for accurate predictions of flow velocity and consequently
bed shear stress in the cross sections. Six classic formulae were applied to
evaluate the non-dimensional bedload transport rate, and the bedload transport
discharge through a river cross section is obtained by integrating the bedload
transport rate over the width of the cross section. The results show that the
root mean square error (RMSE) and mean absolute error (MAE) of velocity and
water discharge were less than 8% of the observed magnitude, while the
correlation coefficient between model predictions and observations was close to
unity. The formulae proposed by Ashida and Michiue (1972), in which particle
collision with the bed is taken into account, and by Camenen and Larson (2005),
which allows for yielding a non-zero bedload transport rate even when the bed
shear stress is smaller than the critical bed shear stress value, appeared to
be more appropriate for predicting the observed bedload transport rate in the
studied cross sections of two gravel-bed rivers. If non-uniform sediment
mixtures were considered, the bedload transport discharge through a
cross-section could change considerably by up to 22.5% of the observed
magnitude. The relations proposed by Ashida and Michiue (1972) and Egiazaroff
(1965) for parameterizing the hiding factor yielded more realistic model
predictions in comparison with observations for the measured data set collected
for the Toltén River, while the one proposed by Wilcock and Crowe (2003)
performs the best for the data set measured for the Danube River.
Keywords
Bedload; Gravel-bed river; One-dimensional lateral distribution
method; Bedload transport discharge
10.
Jiaqi YANG; Limo TANG;
Yuntong SHE; Jiao SUN
Laboratory measurements of the fall velocity of fi ne sediment
in an estuarine environment
Volume
35, Issue 2, 2020
Pages 217-226
ISSN
1001-6279
https://doi.org/10.1016/j.ijsrc.2019.08.003
https://www.sciencedirect.com/science/article/pii/S1001627918302853
Abstract
The study of the fall velocity variation of fine sediment in
estuarine areas plays an important role in determining how various factors
affect the flocculation process. Previous experimental studies have focused
solely on the relation between the median fall velocity and influencing
factors, while in the current study, the variation of the fall velocity in
quiescent water also was examined. The experimental results showed that the
vertical distribution of sediment concentration was more uneven, and larger
variations occurred earlier during the settling process under higher salinity
and/or sediment concentration conditions. The fall velocity initially increased
then decreased over time, peaking at ～20 min after settling began, and stabilizing at a value
similar to that in freshwater, regardless of the initial sediment concentration
and salinity combinations. Along the water depth, the fall velocity increased
monotonically with a gradually decreasing gradient. The median fall velocity
increased then decreased with increased salinity. The salinity at which the
peak fall velocity occurred depended on the initial sediment concentration. The
relation between the median fall velocity and initial sediment concentration
displayed an obvious two-stage pattern (i.e., accelerated flocculation and
decelerated, hindered settling) at higher salinities; whereas the maximum
median fall velocity was observed at two consecutive sediment concentration
values under lower salinity conditions. Finally, an empirical equation
estimating the median fall velocity of cohesive fine sediment was formulated,
incorporating the effects of both salinity and sediment concentration.
Keywords
Laboratory experiments; Fine sediment; Estuarine environment;
Fall velocity; Salinity; Sediment concentration
