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

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.

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

Oceanologia ◽  
2017 ◽  
Vol 59 (1) ◽  
pp. 28-36 ◽  
Author(s):  
Nicolas Guillou ◽  
Aurélie Rivier ◽  
Georges Chapalain ◽  
Francis Gohin
Keyword(s):  
Suspended Sediment ◽  
English Channel ◽  
Near Surface ◽  
Suspended Sediment Concentrations ◽  
The Impact

scholarly journals Impact of Climate Change on Metal and Suspended Sediment Concentrations in Urban Waters

2020 ◽  
Vol 8 ◽  
Author(s):  
Paul Frogner-Kockum ◽  
Gunnel Göransson ◽  
Marie Haeger-Eugensson
Keyword(s):  
Climate Change ◽  
Suspended Sediment ◽  
Contaminant Transport ◽  
Dry Period ◽  
Short Term ◽  
Impact Of Climate Change ◽  
Suspended Sediment Concentrations ◽  
River Loads ◽  
Metal Contaminant ◽  
The Impact

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.

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

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.

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

2006 ◽  
Vol 63 (11) ◽  
pp. 2487-2494 ◽  
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.

scholarly journals Anomalous Reduction of the Total Suspended Matter During the COVID-19 Lockdown in the Hooghly Estuarine System

2021 ◽  
Vol 8 ◽  
Author(s):  
Chiranjivi Jayaram ◽  
Rajdeep Roy ◽  
Neethu Chacko ◽  
Debadatta Swain ◽  
Ramunaidu Punnana ◽  
...  
Keyword(s):  
Suspended Matter ◽  
Anthropogenic Activities ◽  
Positive Influence ◽  
Total Suspended Matter ◽  
Landsat 8 ◽  
Estuarine System ◽  
Carbon Export ◽  
Sediment Removal ◽  
Brick Kilns ◽  
The Impact

The impact of the coronavirus disease 2019 (COVID-19) lockdown in the Hooghly estuarine region, India is assessed using the total suspended matter (TSM) concentration. The estimation of TSM is performed using Landsat-8/operational land imager (OLI), and an intercomparison of TSM load during the pre-lockdown and lockdown periods is done. It is observed that during the lockdown period, TSM reduced by 30–50%. This is a significant observation considering the ecological balance of the region and the fact that it is home to the largest mangroves in the world. This change in suspended matter presumably reflects the influence of reduction in anthropogenic activities owing to the COVID-19 lockdowns, such as industries, closure of shipping activities (through less dredging), and brick kilns (through less sediment removal), which are generally the primary contributors in this region. Even though these observed changes are representative of the positive influence of the COVID-19 lockdown, its implications in estuarine biogeochemistry still remain poorly quantified. The decrease in TSM content may increase light penetration, thereby increasing the primary productivity. In addition, low sediment load reaching the Bay of Bengal could influence the carbon export due to reduction in ballasting effect as reported from this region. In summary, the influence of the COVID-19 lockdown on the biogeochemistry of the aquatic ecosystem appears rather complex than thought earlier and may vary regionally based on local hydrodynamics. The analysis elucidates the complex interplay of regional lockdown and its implication in modulation of local biogeochemistry. However, the relative importance of each process in the Hooghly estuary remains to be fully evaluated.

scholarly journals Scale-breaks of suspended sediment rating in large rivers in Germany induced by organic matter

2020 ◽  
Author(s):  
Thomas O. Hoffmann ◽  
Yannik Baulig ◽  
Helmut Fischer ◽  
Jan Blöthe
Keyword(s):  
Organic Matter ◽  
Suspended Sediment ◽  
Suspended Matter ◽  
Monitoring Network ◽  
Suspended Sediments ◽  
Sediment Supply ◽  
Organic Fraction ◽  
Sediment Rating Curve ◽  
Suspended Sediment Concentrations ◽  
Rating Model

Abstract. Understanding the dynamics of suspended sediment and associated nutrients is of major relevance for sustainable sediment management aiming to achieve healthy river systems. Sediment rating curves are frequently used to analyze the dynamics of suspended sediments and their potential sources and sinks. Here we are using more than 750 000 measurements of the suspended sediment concentrations (SSC) and discharge at 62 gauging stations along 19 waterways in Germany based on the suspended sediment monitoring network of the German water and shipping authority, which started in the 1960ties. Furthermore, we analyse more than 2000 measurements of the loss on ignition (LOI) of suspended matter at two stations along the rivers Moselle and Rhine to asses the mineral and organic fraction of the suspended matter. SSC and LOI are analysed in terms of the power law rating to identify discharge depended process regimes of suspended matter. Our results indicate that for most studied gauging stations, rating coefficients are not constant over the full discharge range, but there is a distinct break in the sediment rating curve, with specific SSC-Q domains above and below this break. The transition of the rating exponent is likely to be a result of a change of controlling factors of the suspended sediment from intrinsic organic matter formation at low flows to extrinsic sediment supply (including mineral and organic fractions) due to hillslope erosion at high flows. Based on these findings we developed a conceptual rating model separating the mineral and organic fraction of the suspended matter in the Germany waterways. This model allows evaluating the sources of the mineral and organic fraction of the suspended matter and gain new insights into the first order control of discharge dynamics of suspended sediments.

scholarly journals Sentinel-2 Reveals Abrupt Increment of Total Suspended Matter While Ever Given Ship Blocked the Suez Canal

Water ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 3286
Author(s):  
Milad Niroumand-Jadidi ◽  
Francesca Bovolo
Keyword(s):  
News Media ◽  
Suspended Matter ◽  
Time Window ◽  
Total Suspended Matter ◽  
Suez Canal ◽  
Trade Routes ◽  
The North ◽  
The Impact ◽  
North And South ◽  
Sentinel 2

The blockage of the Suez Canal, one of the world’s key trade routes, by a giant container ship in March 2021 was in the spotlight of news media worldwide, mainly because of its economic impacts. In this study, we look at this event from an environmental perspective by analyzing the impact of the artificial barrier made by the ship over the channel and of operations like dredging on the concentration of total suspended matter (TSM). In this context, multitemporal Sentinel-2 images are used to study short-term variations of TSM within a time window spanning before, during, and after the blockage event. A well-established neural network-based processor called Case 2 Regional CoastColour (C2RCC) is employed to derive remote sensing reflectance (Rrs) and then TSM concentrations from Sentinel-2 imagery. The results indicate that the stuck ship acted as an artificial barrier leading to very different TSM conditions north and south of the canal. Furthermore, the blockage of the Suez Canal and subsequent dredging caused an abrupt increment (+400%) in the concentration of TSM moving north from the ship’s location. We also identified a very high contrast between the TSM concentration in the north and south of the vessel during the blockage event.

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

2016 ◽  
Vol 4 (3) ◽  
pp. 705-719 ◽  
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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