scholarly journals HYDRODYNAMIC AND COHESIVE SEDIMENT TRANSPORT MODELING IN CHILIKA LAGOON

2018 ◽  
Vol IV-5 ◽  
pp. 141-149
Author(s):  
S. Pradhan ◽  
R. N. Samal ◽  
S. B. Choudhury ◽  
P. K. Mohanty
Keyword(s):  
Suspended Sediment ◽  
Suspended Sediment Concentration ◽  
Sediment Concentration ◽  
Cohesive Sediment ◽  
Chilika Lagoon ◽  
Thickness Change ◽  
North East ◽  
The North ◽  
Bed Thickness ◽  
Lagoon Environment

<p><strong>Abstract.</strong> Chilika lagoon, one of the largest brackish water lagoons in Asia located along the east coast of India. The rivers draining into the lagoon carry about 13 million tonnes of sediments annually. Because of the cohesiveness properties of the fine sediments, nutrients, heavy metals and other polluted substances tend to bind to the sediment’s surface. Consequently, pollutants can be concentrated in the inlets/estuaries, thus being of great environmental interest. In addition, the mudflats occurring are important biotopes for a large number of micro- and macro-faunal species and act as feeding places for a number of birds. To understand the cohesive sediment dynamics, a numerical model, MIKE 21 Mud Transport (MT) coupled with hydrodynamic (HD) was used. The model simulated the relative bed level height and suspended sediment concentrations. The sediment interchange and accumulation between each sectors and Bay of Bengal were evaluated. The suspended sediment concentration is high in the north-east portion of the lagoon while medium and low suspended loads are observed in the eastern and western portion of the lagoon. Bed thickness is very high in the north-western corner of the lagoon covered with Phragmites Karka which facilitate sediment trap. Total bed thickness change is very much pronounced in the northern sector which receives most of the sediments from the Mahanadi river systems as well along the periphery of the lagoon due to drainage. The eastern lagoon shows a net deposition accumulated fraction (5–15<span class="thinspace"></span>kg/m<sup>2</sup>) and hence gives enough indication of the sedimentation processes in the lagoon. Further, the results also warrant immediate attention to check and monitor suspended sediment concentration to find out the net deposition trend in the lagoon environment in order to take decisions in minimizing the sediment load.</p>

scholarly journals Transport Mechanism of Suspended Sediments and Migration Trends of Sediments in the Central Hangzhou Bay

Water ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2189
Author(s):  
Zekun Song ◽  
Weiyong Shi ◽  
Junbiao Zhang ◽  
Hao Hu ◽  
Feng Zhang ◽  
...  
Keyword(s):  
Sediment Transport ◽  
Suspended Sediment ◽  
Suspended Sediment Concentration ◽  
Suspended Sediments ◽  
Sediment Concentration ◽  
Hangzhou Bay ◽  
The South ◽  
Transport Mode ◽  
Tidal Pumping ◽  
The North

Based on the 2013 field survey data of hydrology, suspended sediments and bottom sediments in the Central Hangzhou Bay, this paper explores the dynamic mechanism of suspended sediments in Hangzhou Bay by employing material flux decomposition. Meanwhile, the migration trends of bed sediments are also investigated by analyzing grain size trends. The results show that during an ebb or flood tide, the hydrograph of suspended sediment concentration of Hangzhou Bay is dominated by an M shape (bimodal), which is attributed primarily to the generation of a soft mud layer and a separate fluid mud layer. Laterally, the distribution of suspended sediment concentration is high in the south and low in the north. From a macroscopic perspective, the net sediment transport in the study area displays a “north-landward and south-seaward” trend, presenting a “C”-shaped transport mode. That is, the sediments are transported from the bay mouth to the bay head on the north side and from the bay head to the bay mouth on the south side. The sediment transports by advection and tidal pumping are predominant, while the sediment transport by vertical circulation makes little contribution to the total sediment transport. Moreover, the sediment transport in the center of the reach area is dominated by advection, whereas that near both sides of the banks is controlled by tidal pumping. The asymmetry of the tides, i.e., flood-dominance in the north and ebb-dominance in the south, is the primary cause of the dynamic mechanism for the overall “C”-shaped transport mode in Hangzhou Bay. Additionally, coupled with the narrow-head wide-mouth geomorphology, Hangzhou Bay remains evolving by south shore silting and north shore scouring.

METHODOLOGICAL ASPECTS OF THE SUSPENDED SEDIMENT CONCENTRATION MEASUREMENT IN THE COASTAL ZONE

2017 ◽  
Author(s):  
Рубен Косян ◽  
Ruben Kosyan ◽  
Marina Krylenko ◽  
Marina Krylenko
Keyword(s):  
Suspended Sediment ◽  
Coastal Zone ◽  
Field Experiments ◽  
Suspended Sediment Concentration ◽  
Rotation Axis ◽  
Sediment Concentration ◽  
The North ◽  
Wave Channel ◽  
Mediterranean And Black Seas ◽  
Methodological Aspects

Results of the suspended sediment concentration study in the coastal zone on the basis of field and laboratory experiments are analyzed. Data from field experiments, performed in the coastal zone of the North, Mediterranean and Black seas, are used. The laboratory researches were fulfilled in the Big Wave Channel of the Hannover University. It is shown that to increase the accuracy of measurement it is necessary to take into account the convective mechanism of the sediment suspension, as well as the size, the direction of the rotation axis and other parameters of the turbulent vortices transporting sand sediments. The presented information will help to improve the quality of field data collection.

scholarly journals Indirect Estimation of Flow and Suspended-sediment Concentration and Load in Small Mountain Streams: an Exploratory Study in Ribeira Seca Stream, Madeira Island

2021 ◽  
Vol 16 ◽  
Keyword(s):  
Suspended Sediment ◽  
Exploratory Study ◽  
Suspended Sediment Concentration ◽  
Suspended Sediments ◽  
Sediment Concentration ◽  
Suspended Sediment Transport ◽  
Measurement Campaign ◽  
Indirect Determination ◽  
Madeira Island ◽  
The North

The aim of this study was to assess the applicability of indirect techniques for streamflow and suspended sediment concentration estimation and their use in the calculation of suspended sediment transport rate in the small mountain watersheds of Madeira Island, Portugal. Emphasis was given to the application of salt dilution gauging to the indirect determination of the flow rate and the use of water turbidity data to estimate the concentration of suspended sediments. The field and laboratory work carried out are briefly described, and the main experimental results and the field data from the short measurement campaign performed in the Ribeira Seca stream in Faial, on the north side of the island, are presented and discussed. Whilst the measurement campaign carried out was temporally and spatially limited, it was pioneering for Madeira and allowed to verify the applicability of the indirect hydrometric and sedimentometric techniques used in this exploratory study.

Analysis of tidal average saturated suspended sediment concentration of cohesive sediment in the Yangtze Estuary

2021 ◽  
Author(s):  
Junyu Tao ◽  
Peng Hu ◽  
Wei Li ◽  
Zhiguo He
Keyword(s):  
Suspended Sediment ◽  
Suspended Sediment Concentration ◽  
Sediment Concentration ◽  
Cohesive Sediment ◽  
Yangtze Estuary ◽  
Shear Stresses ◽  
The Yangtze Estuary ◽  
Erosion And Deposition ◽  
Deposition Fluxes ◽  
The Impact

&lt;p&gt;It is generally believed that sediment erosion and deposition can&amp;#8217;t occur simultaneously, which is also reflected in the classical Partheniades-Krone formulas used to calculate erosion and deposition flux. In this study, the erosion and deposition fluxes of cohesive sediment are integrated in the tidal period respectively, and when they are equal, the corresponding suspended cohesive sediment concentration is called &amp;#8216;tidal average saturated concentration of cohesive sediment&amp;#8217;. Theoretical analysis of the factors affecting the saturated concentration indicates that a large erosion coefficient results in a high saturated concentration level. The corresponding critical erosion and deposition shear stresses (i.e., &amp;#964;&lt;sub&gt;e &lt;/sub&gt;and &amp;#964;&lt;sub&gt;d&lt;/sub&gt;) at saturated concentration have many possibilities. Therefore, it is understandable that good agreement of suspended sediment concentration between simulation and observation have been obtained by adjusting &amp;#964;&lt;sub&gt;e &lt;/sub&gt;and &amp;#964;&lt;sub&gt;d &lt;/sub&gt;in the previous numerical simulation calibration. According to the relative magnitude of &amp;#964;&lt;sub&gt;e &lt;/sub&gt;and &amp;#964;&lt;sub&gt;d&lt;/sub&gt; at saturated concentration, the erosion and deposition fluxes of cohesive sediment can be divided into four situations: weak erosion (i.e., &amp;#964;&lt;sub&gt;e&amp;#160; &gt;&lt;/sub&gt;&amp;#160;&amp;#964;&lt;sub&gt;d&lt;/sub&gt;), intense erosion (i.e., &amp;#964;&lt;sub&gt;e&amp;#160; &lt;&lt;/sub&gt;&amp;#160;&amp;#964;&lt;sub&gt;d&lt;/sub&gt;), intense deposition (i.e., &amp;#964;&lt;sub&gt;e&amp;#160; &lt;&lt;/sub&gt;&amp;#160;&amp;#964;&lt;sub&gt;d&lt;/sub&gt;), and weak deposition (i.e., &amp;#964;&lt;sub&gt;e &gt; &lt;/sub&gt;&amp;#964;&lt;sub&gt;d&lt;/sub&gt; ). A two-dimensional numerical model is applied to calculate the temporal and spatial variation of the saturated concentration of cohesive sediment in the Yangtze Estuary. Simulation results shows the following findings. 1) The impact of the fraction of the kth size class in the surface (top) layer of bed material on erosion flux of non-uniform cohesive sediment is necessary to be considered. Otherwise, the calculated saturated concentration of cohesive sediment is greater than the measured. 2) The differences between saturated concentration and the field calculated/measured suspended sediment concentration can be applied to infer bed erosion/deposition characteristics to some extent, and compared it with the measured erosion/deposition result, which in turn verifies the values of&amp;#160; &amp;#964;&lt;sub&gt;e &lt;/sub&gt;and &amp;#964;&lt;sub&gt;d&lt;/sub&gt; in the model. This finding provides insights for the following research on transport and diffusion of cohesive sediment in estuary and coastal areas.&lt;/p&gt;

METHODOLOGICAL ASPECTS OF THE SUSPENDED SEDIMENT CONCENTRATION MEASUREMENT IN THE COASTAL ZONE

2017 ◽  
Author(s):  
Рубен Косян ◽  
Ruben Kosyan ◽  
Marina Krylenko ◽  
Marina Krylenko
Keyword(s):  
Suspended Sediment ◽  
Coastal Zone ◽  
Field Experiments ◽  
Suspended Sediment Concentration ◽  
Rotation Axis ◽  
Sediment Concentration ◽  
The North ◽  
Wave Channel ◽  
Mediterranean And Black Seas ◽  
Methodological Aspects

Results of the suspended sediment concentration study in the coastal zone on the basis of field and laboratory experiments are analyzed. Data from field experiments, performed in the coastal zone of the North, Mediterranean and Black seas, are used. The laboratory researches were fulfilled in the Big Wave Channel of the Hannover University. It is shown that to increase the accuracy of measurement it is necessary to take into account the convective mechanism of the sediment suspension, as well as the size, the direction of the rotation axis and other parameters of the turbulent vortices transporting sand sediments. The presented information will help to improve the quality of field data collection.

scholarly journals Remote Sensing of Suspended Sediment Over Gulf of Martaban

2015 ◽  
Vol 34 (1) ◽  
Author(s):  
Abd Rahman Matamin ◽  
Fadhli Ahmad ◽  
Mustafa Mamat ◽  
Khiruddin Abdullah ◽  
Shahariah Harun
Keyword(s):  
Remote Sensing ◽  
Suspended Sediment ◽  
Suspended Sediment Concentration ◽  
Monsoon Season ◽  
Sediment Concentration ◽  
Yearly Variation ◽  
The North ◽  
The World ◽  
Sediment Cover ◽  
Sw Monsoon

AbstractGulf of Martaban is located at the north of Andaman, and is one of the world most turbid areas. The presence of suspended sediment concentration (SSC) in the water body could reduce the underwater transmittance. This study has been conducted to investigate the variation of SSC over the Gulf of Martaban. Remote sensing reflectance (Rrs) of 667 nm is used as a proxy to represent the sediment SSC variation over the study area. The data for the period of July 2002 to March 2014 acquired from MODIS Aqua 4 km resolution are used in this study. As a result, there is no obvious yearly variation in the SSC cover area. The SSC variation over this study area is found to be seasonal. High homogenous SSC covers area observably during the northeast (NE) monsoon season that occurs from December to January. The sediment cover area could reach the latitude of 15°N that located at the south of the gulf. During southwest (SW) monsoon season that occurs from May to September, low and sparse SSC cover area is observed. As a consequence, the area covered by the SSC is higher during the NE monsoon season as compared to the SW monsoon season. Hence, the SSC cover area during the NE monsoon season is greater than the yearly averaged SSC cover area. Meanwhile the SSC cover area during the rainy SW monsoon season is less than the yearly and NE monsoon season.

Influence of Upstream Runoff Variation on Suspended Sediment in Yangtze Estuary

2012 ◽  
Vol 256-259 ◽  
pp. 2573-2576 ◽  
Author(s):  
Chao Feng Tong ◽  
Tao Yin ◽  
Jian Shi ◽  
Yu Yang Shao
Keyword(s):  
Suspended Sediment ◽  
Suspended Sediment Concentration ◽  
Concentration Field ◽  
Sediment Concentration ◽  
Yangtze Estuary ◽  
Hangzhou Bay ◽  
The Yangtze Estuary ◽  
The North ◽  
Runoff Variation ◽  
Water Conservancy Project

For the construction of water conservancy project in the upstream of the Yangtze River and the human activities, the runoff and sediment discharge from the upstream to East China Sea have changed greatly. To explore the distribution characteristics of suspended sediment in Yangtze Estuary under the new upstream boundary condition, a 2-D flow-sediment numerical model including the Yangtze Estuary and the Hangzhou Bay was established. Four different runoffs, which are 4,620m³/s, 11,000m³/s, 75,900m³/s and 90,000m³/s respectively, and the correspond sediment discharges were considered. The result indicates that, with the increase of upstream runoff, the sediment intrusion from the top of the North Branch into the North Branch decreases and the suspended sediment concentration field in the South Branch changes is greater than that in the North Branch. In the same region, the sediment concentration decreases during rising tide while it increases at low tide. The change of the core position for suspended sediment field is insignificant.

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