The impact of tides and waves on near-surface suspended sediment concentrations in the English Channel

In order to study the impact of climate change on metal contaminant transport in urban waters and its relevance for water quality, we have analyzed variations in metal- and suspended sediment concentrations (SSC) in three urban rivers and one small creek in the Gothenburg region during various hydrological events such as spring flood, dry period, and wet period. To interpret river loads of metals and SSC we have furthermore followed meteorological trends since 1961 and additionally calculated future trends for the Gothenburg region, located on the west coast of Sweden. During periods of a short-term increase in precipitation we found an increased particle bound metal transport in urban watercourses of the Göta Älv River. In addition, a correlation between studied parameters indicates that surface runoff from brownfields most likely is the main source to the increased transport of pollutants in river systems rather than re-suspension of polluted river sediment.

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Reduced fine sediment flux in response to the managed diversion of an upland river channel

Earth Surface Dynamics Discussions ◽

10.5194/esurfd-3-1179-2015 ◽

2015 ◽

Vol 3 (4) ◽

pp. 1179-1220

Author(s):

M. T. Perks ◽

J. Warburton

Keyword(s):

Suspended Sediment ◽

Fine Sediment ◽

Sediment Flux ◽

Analysis Of Covariance ◽

Before And After ◽

Suspended Sediment Concentrations ◽

Sediment Transfer ◽

The Uk ◽

The Impact ◽

B Coefficients

Abstract. This paper describes the implementation of a novel mitigation approach and subsequent adaptive management, designed to reduce the transfer of fine sediment in Glaisdale Beck; a small upland catchment in the UK. Hydro-meteorological and suspended sediment datasets are collected over a two year period spanning pre- and post-diversion periods in order to assess the impact of the channel reconfiguration scheme on the fluvial suspended sediment dynamics. Analysis of the river response demonstrates that the fluvial sediment system has become more restrictive with reduced fine sediment transfer. This is characterised by reductions in flow-weighted mean suspended sediment concentrations from 77.93 mg L−1 prior to mitigation, to 74.36 mg L−1 following the diversion. A Mann–Whitney U test found statistically significant differences (p < 0.001) between the pre- and post-monitoring median SSCs. Whilst application of one-way analysis of covariance (ANCOVA) on the coefficients of sediment rating curves developed before and after the diversion found statistically significant differences (p < 0.001), with both Log a and b coefficients becoming smaller following the diversion. Non-parametric analysis indicates a reduction in residuals through time (p < 0.001), with the developed LOWESS model over-predicting sediment concentrations as the channel stabilises. However, the channel is continuing to adjust to the reconfigured morphology, with evidence of a headward propagating knickpoint which has migrated 120 m at an exponentially decreasing rate over the last 7 years since diversion. The study demonstrates that channel reconfiguration can be effective in mitigating fine sediment flux in upland streams but the full value of this may take many years to achieve whilst the fluvial system, slowly readjusts.

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The effect of suspended sediment on fertilization success in sockeye (Oncorhynchus nerka) and coho (Oncorhynchus kisutch) salmon

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f06-133 ◽

2006 ◽

Vol 63 (11) ◽

pp. 2487-2494 ◽

Cited By ~ 12

Author(s):

Ryan V Galbraith ◽

Erland A MacIsaac ◽

J Stevenson Macdonald ◽

Anthony P Farrell

Keyword(s):

Suspended Sediment ◽

Pacific Salmon ◽

Oncorhynchus Nerka ◽

Oncorhynchus Kisutch ◽

Sediment Concentration ◽

Fertilization Success ◽

Suspended Sediment Concentrations ◽

Controlled Flow ◽

The Impact ◽

The Relationship

Suspended sediment is a naturally occurring part of aquatic ecosystems, and unnatural elevation of suspended sediment in streams above background concentrations is known to adversely affect Pacific salmon (Oncorhynchus spp.) at different life stages. Conspicuously lacking in the literature is knowledge of the effect of suspended sediment on egg fertilization success during spawning. Sockeye (Oncorhynchus nerka) and coho (Oncorhynchus kisutch) salmon gametes were used to investigate the impact of different concentrations of suspended sediment particles on the ability of sperm to successfully fertilize eggs. The fertilization process was simulated using a controlled-flow water flume with concentrations of suspended particles ranging from 800 to 47 000 mg·L–1. Egg fertilization success was assessed at eyed stage after incubating eggs in the streambed in the field or in artificial laboratory egg incubation (Heath) trays. Regression model analysis showed that suspended sediment concentrations reduced the percent of fertilized eggs and that reduction in successful fertilization below 80% could occur when suspended sediment levels are in excess of 9000 mg·L–1. The relationship derived herein serves as a preliminary guideline for determining the effect size of suspended sediment concentration on egg fertilization success during spawning.

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Detection of the Minute Variations of Total Suspended Matter in Strong Tidal Waters Based on GaoFen-4 Satellite Data

Remote Sensing ◽

10.3390/rs13071339 ◽

2021 ◽

Vol 13 (7) ◽

pp. 1339

Author(s):

Qiong Chen ◽

Bin Zhou ◽

Zhifeng Yu ◽

Jie Wu ◽

Shilin Tang

Keyword(s):

Suspended Sediment ◽

Suspended Matter ◽

Bottom Topography ◽

Observation Time ◽

Total Suspended Matter ◽

Tidal Range ◽

Hangzhou Bay ◽

Time Interval ◽

Suspended Sediment Concentrations ◽

The Impact

Hangzhou Bay (HZB) is the largest macro-tidal bay in China, where suspended sediment concentrations are significantly modulated by tidal oscillations. This makes it an ideal area for the study of the impact of tide on temporal–spatial variation in suspended sediment. The GaoFen-4 (GF-4) satellite is the first high-resolution geosynchronous orbiting satellite of China. It exhibits the unique advantages of capturing minute variations and finer details of total suspended matter (TSM) due to the enhancement in spatial resolution (50 m) and observation time interval (20 s). In this study, TSM concentration of the HZB was retrieved based on the GF-4 satellite. The spatial distribution and minute variations of TSM concentration under the ebb tide from 7:30 to 7:40 a.m. on 28 August 2017, were analyzed. The results showed that the average TSM concentration inside HZB was (371.8 ± 1.8) mg/L. There was a linearly increasing trend of TSM concentration at ebb tide, with an increment of (3.96 ± 0.31) (mg/L)/min, and a more significant increase was observed in the high TSM areas. This increase in TSM concentration was associated with both the bottom topography and tide processes. The tidal potential energy generated by the tidal range and the strong shear stress generated by the high current velocity both led to the re-suspension of the sedimentary particles, which affected the variation of TSM concentration. In addition, the influence of bottom topography changed the intensity of re-suspension and also affected the distribution of TSM concentration in HZB.

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Modeling Near-Surface Suspended Sediment Concentration in the English Channel

Journal of Marine Science and Engineering ◽

10.3390/jmse3020193 ◽

2015 ◽

Vol 3 (2) ◽

pp. 193-215 ◽

Cited By ~ 6

Author(s):

Nicolas Guillou ◽

Aurélie Rivier ◽

Francis Gohin ◽

Georges Chapalain

Keyword(s):

Suspended Sediment ◽

Suspended Sediment Concentration ◽

Sediment Concentration ◽

English Channel ◽

Near Surface

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Reduced fine sediment flux and channel change in response to the managed diversion of an upland river channel

Earth Surface Dynamics ◽

10.5194/esurf-4-705-2016 ◽

2016 ◽

Vol 4 (3) ◽

pp. 705-719 ◽

Cited By ~ 2

Author(s):

Matthew Thomas Perks ◽

Jeff Warburton

Keyword(s):

Suspended Sediment ◽

Fine Sediment ◽

Sediment Flux ◽

Analysis Of Covariance ◽

Data Sets ◽

Before And After ◽

Suspended Sediment Concentrations ◽

Sediment Data ◽

The Uk ◽

The Impact

Abstract. This paper describes the implementation of a novel mitigation approach and subsequent adaptive management, designed to reduce the transfer of fine sediment (< 2 mm) in Glaisdale Beck, a small, predominantly upland catchment in the UK. Hydro-meteorological and suspended sediment data sets are collected over a 2-year period spanning pre- and post-diversion periods in order to assess the impact of the channel reconfiguration scheme on the fluvial suspended sediment dynamics. Analysis of the river response demonstrates that the fluvial sediment system has become more restrictive with reduced fine sediment transfer. This is characterized by reductions in flow-weighted mean suspended sediment concentrations from 77.93 mg L−1 prior to mitigation, to 74.36 mg L−1 following the diversion. A Mann–Whitney U test found statistically significant differences (p < 0.001) between the pre- and post-monitoring median suspended sediment concentrations (SSCs). Whilst application of one-way analysis of covariance (ANCOVA) on the coefficients of sediment rating curves developed before and after the diversion found statistically significant differences (p < 0.001), with both Loga and b coefficients becoming smaller following the diversion. Non-parametric analysis indicates a reduction in residuals through time (p < 0.001), with the developed LOWESS model over-predicting sediment concentrations as the channel stabilizes. However, the channel is continuing to adjust to the reconfigured morphology, with evidence of a headward propagating knickpoint which has migrated 120 m at an exponentially decreasing rate over the last 7 years since diversion. The study demonstrates that channel reconfiguration can be effective in mitigating fine sediment flux in headwater streams but the full value of this may take many years to achieve whilst the fluvial system slowly readjusts.

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Estimating suspended sediment concentrations from ocean colour measurements in moderately turbid waters; the impact of variable particle scattering properties

Remote Sensing of Environment ◽

10.1016/j.rse.2004.11.002 ◽

2005 ◽

Vol 94 (3) ◽

pp. 373-383 ◽

Cited By ~ 138

Author(s):

C.E. Binding ◽

D.G. Bowers ◽

E.G. Mitchelson-Jacob

Keyword(s):

Suspended Sediment ◽

Particle Scattering ◽

Ocean Colour ◽

Turbid Waters ◽

Colour Measurements ◽

Suspended Sediment Concentrations ◽

The Impact

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A Method for Evaluating Intensity of Water Cavitation Peening Processing

Materials Science Forum ◽

10.4028/www.scientific.net/msf.675-677.747 ◽

2011 ◽

Vol 675-677 ◽

pp. 747-750

Author(s):

B. Han ◽

Dong Ying Ju ◽

Xiao Guang Yu

Keyword(s):

Residual Stress ◽

Process Capability ◽

Diffraction Method ◽

Spring Steel ◽

Bubble Collapse ◽

Plastic Layer ◽

Process Conditions ◽

X Ray Diffraction ◽

Near Surface ◽

The Impact

Water cavitation peening (WCP) with aeration, namely, a new ventilation nozzle with aeration is adopted to improve the process capability of WCP by increasing the impact pressure induced by the bubble collapse on the surface of components. In this study, in order to investigate the process capability of the WCP with aeration a standard N-type almen strips of spring steel SAE 1070 was treated byWCP with various process conditions, and the arc height value and the residual stress in the superficial layers were measured by means of the Almen-scale and X-ray diffraction method, respectively. The optimal fluxes of aeration and the optimal standoff distances were achieved. The maximum of arc height value reach around 150μm. The depth of plastic layer observed from the results of residual stresses is up to 150μm. The results verify the existence of macro-plastic strain in WCP processing. The distributions of residual stress in near-surface under different peening intensity can provide a reference for engineers to decide the optimal process conditions of WCP processing.

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Assessing the regional impacts of Mexico City emissions on air quality and chemistry

Atmospheric Chemistry and Physics ◽

10.5194/acp-9-3731-2009 ◽

2009 ◽

Vol 9 (11) ◽

pp. 3731-3743 ◽

Cited By ~ 35

Author(s):

M. Mena-Carrasco ◽

G. R. Carmichael ◽

J. E. Campbell ◽

D. Zimmerman ◽

Y. Tang ◽

...

Keyword(s):

Air Quality ◽

Mexico City ◽

Ozone Production ◽

Anthropogenic Aerosol ◽

Near Surface ◽

Mixing Ratios ◽

Regional Impacts ◽

Photolysis Rates ◽

Regional Air Quality ◽

The Impact

Abstract. The impact of Mexico City (MCMA) emissions is examined by studying its effects on air quality, photochemistry, and on ozone production regimes by combining model products and aircraft observations from the MILAGRO experiment during March 2006. The modeled influence of MCMA emissions to enhancements in surface level NOx, CO, and O3 concentrations (10–30% increase) are confined to distances <200 km, near surface. However, the extent of the influence is significantly larger at higher altitudes. Broader MCMA impacts (some 900 km Northeast of the city) are shown for specific outflow conditions in which enhanced ozone, NOy, and MTBE mixing ratios over the Gulf of Mexico are linked to MCMA by source tagged tracers and sensitivity runs. This study shows that the "footprint" of MCMA on average is fairly local, with exception to reactive nitrogen, which can be transported long range in the form of PAN, acting as a reservoir and source of NOx with important regional ozone formation implications. The simulated effect of MCMA emissions of anthropogenic aerosol on photochemistry showed a maximum regional decrease of 40% in J[NO2→NO+O], and resulting in the reduction of ozone production by 5–10%. Observed ozone production efficiencies are evaluated as a function of distance from MCMA, and by modeled influence from MCMA. These tend to be much lower closer to MCMA, or in those points where modeled contribution from MCMA is large. This research shows that MCMA emissions do effect on regional air quality and photochemistry, both contributing large amounts of ozone and its precursors, but with caveat that aerosol concentrations hinder formation of ozone to its potential due to its reduction in photolysis rates.

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The Impact of Finer-Resolution Air–Sea Coupling on the Intraseasonal Oscillation of the Indian Monsoon

Journal of Climate ◽

10.1175/2010jcli3868.1 ◽

2011 ◽

Vol 24 (10) ◽

pp. 2451-2468 ◽

Cited By ~ 38

Author(s):

Nicholas P. Klingaman ◽

Steven J. Woolnough ◽

Hilary Weller ◽

Julia M. Slingo

Keyword(s):

Atmospheric Stability ◽

Intraseasonal Oscillation ◽

Boreal Summer ◽

Upper Ocean ◽

Vertical Resolution ◽

Coupled Models ◽

Diurnal Variability ◽

Near Surface ◽

The Impact ◽

Coupling Frequency

Abstract A newly assembled atmosphere–ocean coupled model, called HadKPP, is described and then used to determine the effects of subdaily air–sea coupling and fine near-surface ocean vertical resolution on the representation of the Northern Hemisphere summer intraseasonal oscillation. HadKPP comprises the Hadley Centre atmospheric model coupled to the K-Profile Parameterization ocean boundary layer model. Four 30-member ensembles were performed that vary in ocean vertical resolution between 1 and 10 m and in coupling frequency between 3 and 24 h. The 10-m, 24-h ensemble exhibited roughly 60% of the observed 30–50-day variability in sea surface temperatures and rainfall and very weak northward propagation. Enhancing only the vertical resolution or only the coupling frequency produced modest improvements in variability and just a standing intraseasonal oscillation. Only the 1-m, 3-h configuration generated organized, northward-propagating convection similar to observations. Subdaily surface forcing produced stronger upper-ocean temperature anomalies in quadrature with anomalous convection, which likely affected lower-atmospheric stability ahead of the convection, causing propagation. Well-resolved air–sea coupling did not improve the eastward propagation of the boreal summer intraseasonal oscillation in this model. Upper-ocean vertical mixing and diurnal variability in coupled models must be improved to accurately resolve and simulate tropical subseasonal variability. In HadKPP, the mere presence of air–sea coupling was not sufficient to generate an intraseasonal oscillation resembling observations.

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