scholarly journals ANNUAL CHANGES OF BEACH PROFILE AND NEARSHORE SEDIMENT DISTRIBUTION OFF DUNGUN-KEMAMAN,TERENGGANU, MALAYSIA

2018 ◽  
Vol 80 (5) ◽  
Author(s):  
Rosnan Yaacob ◽  
Hasrizal Shaari ◽  
Noraisyah Sapon ◽  
Mohd Fadhli Ahmad ◽  
Effi Helmi Arifin ◽  
...  
Keyword(s):  
Surf Zone ◽  
River Mouth ◽  
Coarse Sand ◽  
Sediment Distribution ◽  
Proper Understanding ◽  
Sediment Size ◽  
Dominant Component ◽  
Beach Processes ◽  
Mean Size ◽  
One Year

A proper understanding of beach processes must include the adjacent shallow marine waters or nearshore environment. This paper focused on the sedimentological and morphological investigation of Terengganu coastal area stretch lies between Dungun and Kemaman. The study area comprised five beaches and 36 nearshore stations. The present investigation attempts to study the time variation of the grain-size along the coast and in order to observe one-year cycle of the perpendicular profile of the beach. Teluk Lipat beach faced a huge modification compared to other beaches. The severely-eroded beaches in the study area characterized by coarse sand. Sediments from backshore and upper beach zone decreased in mean size and became poorly sorted towards surf zone area. Meanwhile, superficial sediment distribution of nearshore area revealed that silt is the most dominant component and the sediment size became coarser towards the shoreline. The results favor an alternative explanation, indicating that the river is the main source for the coastal sands, which are probably reworked by longshore currents on opposite directions apart from the river mouth, resulting on coastal propagation.

AGGREGATE SIZE DISTRIBUTION OF SELECTED TERENGGANU BEACH AREA

2015 ◽  
Vol 77 (32) ◽  
Author(s):  
Noraisyah Sapon ◽  
Rosnan Yaacob ◽  
Mohd-Lokman Husain ◽  
Mohd-Zaini Mustapa ◽  
Rokiah Suriadi
Keyword(s):  
Grain Size ◽  
High Tide ◽  
Size Fraction ◽  
River Mouth ◽  
Aggregate Size ◽  
Coarse Grained ◽  
Northeast Monsoon ◽  
Sediment Size ◽  
Mean Size ◽  
One Year

In general, the Terengganu beaches consist mainly of medium- to coarse-grained sand. Grain sizes were determined by dry sieving sediments; samples represent the upper 15 cm of surficial sediment, collected from the three main geomorphological tidal units during one year observation periods, covering the southwest and northeast monsoon seasons. The result demonstrates a good relationship between the monsoonal processes and the corresponding geomorphological elements. There are some differences between the various geomorphological tidal units, with a subtle trend from the low tide to high tide zone. Grain size decreases slightly from the low tide to the high tide. The sediment size fraction averaging from -0.48phi to 1.87phi. The most fine material was found at Kuala Besut (northernmost Terengganu) while the coarsest particle was found at Seberang Takir. However, the grain size parameters at different beach locations do not suggest a general trend of long-shore variations, except on the beach close to the river mouth. The differences between the seasons were larger than those between the geomorphological tidal units. During the northeast monsoon the mean size was coarser, sorting was worse and the distribution was more positively skewed.

scholarly journals SUSPENDED LOAD CALCULATIONS IN A TIDAL ESTUARY

1970 ◽  
Vol 1 (12) ◽  
pp. 117
Author(s):  
Brian A. O'Connor
Keyword(s):  
Salinity Gradient ◽  
Coarse Sand ◽  
Gradient Term ◽  
Sediment Distribution ◽  
Tidal Estuary ◽  
Fine Grained ◽  
Sediment Size ◽  
Starting Point ◽  
The Vertical Distribution ◽  
Distribution Equation

The present work describes the derivation of equations which can represent the vertical distribution of sediment in a well mixed tidal estuary The starting point for the analysis is the two dimensional longitudinal equation of motion, including the longitudinal salinity gradient term Equations are given which represent a steady state sediment profile and it is shown that these are similar to the expression used in urn-directional flow e g Rouse's equation It is argued that the derived equations could be applied to a real estuary, subject to certain restrictions on sediment size and estuary type An application of the theoretical equations to the Mersey Estuary indicates reasonable agreement between observed and predicted sediment quantities for medium and coarse sand particles Agreement is shown to be worst for fine grained sediments and it is concluded that much better results can be obtained by using the non-steady one dimensional sediment distribution equation in discrete steps throughout the tidal cycle.

Evolution of a nourished sand beach under low wave energy in Thailand

Shore & Beach ◽  
2021 ◽  
pp. 36-54
Author(s):  
Jirat Laksanalamai ◽  
Nobuhisa Kobayashi
Keyword(s):  
Water Depth ◽  
Wave Energy ◽  
Surf Zone ◽  
Tidal Range ◽  
Gulf Of Thailand ◽  
Medium Sand ◽  
Sand Beach ◽  
Profile Changes ◽  
One Year ◽  
Upper Gulf Of Thailand

Sand beaches are essential for coastal tourism in Thailand, but erosion narrowed some beaches significantly over the years. Pattaya is a famous resort near Bangkok in the upper Gulf of Thailand. The Pattaya beach is microtidal with the average tidal range of 1.5 m. The average significant wave height is 0.2 m and the wave energy is low. The beach was widened by placing 130 m3/m of medium sand along the shoreline length of 2.8 km between two terminal groins constructed in 2018. The bathymetry and topography were measured in 2015, 2019, and 2020. Approximately 14% of the placed sand in the water depth less than 2 m was lost after one year, as may be expected for nourished beaches. The bathymetry change in the water depth of 2-4 m varied alongshore. The sand volume change in this offshore zone beyond the surf zone was as large as that in the landward sand placement zone. The assumption of negligible profile changes seaward of a closure depth is not applicable to this beach during 2015-2020.

scholarly journals Spatial Distribution of Δ14C Values of Organic Matter in Surface Sediments Off Saru River in Northern Japan, One Year After a Flood Event in 2006

Radiocarbon ◽  
2010 ◽  
Vol 52 (3) ◽  
pp. 1068-1077
Author(s):  
Seiya Nagao ◽  
Tomohisa Irino ◽  
Takafumi Aramaki ◽  
Ken Ikehara ◽  
Hajime Katayama ◽  
...  
Keyword(s):  
Organic Matter ◽  
River Mouth ◽  
Flood Event ◽  
Terrestrial Organic Matter ◽  
Sampling Area ◽  
Restricted Area ◽  
One Year ◽  
Sandy Sediments ◽  
Riverine Suspended Solids ◽  
Northern Japan

Dispersion and deposition of terrestrial organic matter by flooding on the inner shelf were studied using C/N ratios, δ13C, and Δ14C values of sedimentary organic matter. Surface sediment samples (top 2 cm) were collected from coastal areas near the Saru River in southwestern Hokkaido, northern Japan, 1 yr after a flood event in 2006. Riverine suspended solids were also collected at a fixed station downstream during 2006–2008. Sandy sediments were located at the front of the river mouth and the western part of the sampling area, with the δ13C of organic matter ranging from −23.8‰ to −22.0‰, Δ14C of –655‰ to –388‰, and an organic carbon/total nitrogen (C/N) ratio of 5.9–7.7. On the other hand, silt and clay sediments were distributed in a restricted area 11–16 km from the river mouth, with lighter δ13C (–26.7‰ to −24.1‰) and higher Δ14C (–240‰ to –77‰) of organic matter and C/N ratio (7.8–13.3). From end-member analysis, the apparently younger and less degraded organic matter in the silt and clay sediments consists mainly of terrestrial organic matter released by flood events. They remain in the depression, although most flood deposits were moved to deep-sea environments.

scholarly journals INFRAGRAVITY PERIOD OSCILLATIONS IN A CHANNEL HARBOR NEAR A RIVER MOUTH

2018 ◽  
pp. 8 ◽  
Author(s):  
Florian Bellafont ◽  
Denis Morichon ◽  
Volker Roeber ◽  
Gaël André ◽  
Stéphane Abadie
Keyword(s):  
Return Period ◽  
Pressure Sensors ◽  
River Mouth ◽  
Type Model ◽  
Storm Event ◽  
Mooring Lines ◽  
Long Period ◽  
One Year ◽  
Free Propagation ◽  
Resonance Oscillations

Port of Bayonne, located in SW France, is a channel harbor situated near the river mouth of the Adour. Long-period oscillations have repeatedly caused snapping of mooring lines of berthed ships and have led to wave resonances in an adjacent marina (seiche). To investigate mechanisms for generation of theses oscillations, a field campaign was carried out during a one-year return-period storm (Hs = 6 m and Tp = 15 s): four pressure sensors were deployed inside the port. To complement the data and to better understand the governing processes that lead to the wave transformations in Port of Bayonne, the storm event was computed with the Boussinesq-type model, BOSZ. The data confirm the model results, which show generation of long infragravity (IG) waves by the incident swell around the harbor entrance and free propagation of these waves without amplification over far distances inside Port of Bayonne. Excited by these long waves, resonance oscillations are only noticeable in a small enclosed marina. Though the IG-waves are not causing substantial changes to the water level along the harbor channel, they are suspected to excite the ships’ eigen modes, which consequently results in mooring problems.

Downstream Movements and Estuarine Residence by Atlantic Salmon Parr (Salmo salar)

1989 ◽  
Vol 46 (9) ◽  
pp. 1466-1471 ◽  
Author(s):  
R. A. Cunjak ◽  
E. M. P. Chadwick ◽  
M. Shears
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Significant Proportion ◽  
River Mouth ◽  
Northwest Coast ◽  
Total Production ◽  
Younger Age ◽  
Mean Size ◽  
Salmon Parr ◽  
Atlantic Salmon Parr

Downstream migrations and estuarine residence by Atlantic salmon (Salmo salar) parr and smolts were studied in a small river on the northwest coast of Newfoundland in 1983 and in 1987. There were large downstream migrations in the spring and small downstream migrations in the fall. The major differences between the two types of migrant were that parr migrated about 1 wk before smolts and at a younger age compared with smolts and while parr remained in the estuary throughout the summer, smoits did not. Modal age and mean size were less for parr sampled in the estuary compared with those sampled at the counting-fence which suggested that the smallest parr were not captured by the fence. The estuarine population of parr represented a significant proportion of the river's total production of salmon. Parr were found throughout the estuary in salinities up to 24 parts per thousand but were most abundant near the river mouth. There was evidence that larger parr became smolts and eventually migrated to sea, but smaller parr probably returned to the river for overwintering. It is clear that estuaries should be included as habitat used for rearing Atlantic salmon.

Geographical Variation in Corroboree Frogs, Pseudophryne Corroboree Moore (Anura: Myobatrachidae): a Reappraisal Supports Recognition of P-Pengilleyi Wells &Wellington

1996 ◽  
Vol 44 (6) ◽  
pp. 569 ◽  
Author(s):  
WS Osborne ◽  
RA Zentelis ◽  
M Lau
Keyword(s):  
Morphological Characters ◽  
Colour Pattern ◽  
Separate Species ◽  
Advertisement Calls ◽  
Form Analysis ◽  
Southern Form ◽  
Mean Size ◽  
The Mean ◽  
One Year ◽  
Breeding Seasons

The extent of divergence in morphology and colour-pattern between allopatric populations of the corroboree frog, Pseudophyrne corroboree, was assessed over three breeding seasons by examination of eggs, tadpoles and adults throughout the distributional range of the species. Advertisement calls of individuals from each of the populations also were recorded and analysed. The mean size of adults was found to vary considerably between years; however, within any one year individuals from the Snowy Mountains (southern form) were significantly larger than individuals from the Brindabella Range and Fiery Range (northern form), with the differences apparently not simply related to environmental influences. Multivariate analysis of quantitative morphological characters and colour-pattern separated the frogs into two distinct geographic groups corresponding with the northern form and southern form. Analysis of advertisement calls indicated that there were slight differences in the structure of the calls of the two forms, with the main differences being in call duration and number of pulses. These results, combined with the previously described genetic differences, support their recognition as separate species. It is recommended that the name P. corroboree be restricted to the southern form and that the northern form be referred to as P. pengilleyi Wells & Wellington.

scholarly journals WIND-GENERATED LONGSHORE CURRENTS

1978 ◽  
Vol 1 (16) ◽  
pp. 84
Author(s):  
Dag Nummedal ◽  
Robert J. Finley
Keyword(s):  
South Carolina ◽  
Surf Zone ◽  
Environmental Parameters ◽  
Stepwise Multiple Regression ◽  
Longshore Current ◽  
Statistical Data Analysis ◽  
Data Set ◽  
Seasonal Basis ◽  
Independent Variable ◽  
One Year

This paper evaluates, through the use of a stepwise multiple regression procedure, whether parameters descriptive of the surf-zone wave field adequately explain the variability in longshore current velocities, or if the inclusion of additional physical environmental parameters could significantly improve the ability to predict such currents. The data set consists of 250 LEO - observations, collected on a seasonal basis over one year, at Debidue Island beach, South Carolina. A regression analysis was performed both on linear combinations of all measured wave parameters, and on nonlinear parameter combinations proposed in various semiempirical predictive equations. Invariably, in all the regression analyses, the longshore component of the wind velocity proved to be the independent variable explaining most of the observed variance in the current velocity. Therefore, the statistical data analysis presented in this paper strongly suggests that wind stress can be a most significant factor in surf-zone current generation.

scholarly journals Análise Montante-Jusante da Granulometria dos Sedimentos de Fundo e Suspenso do Rio Negro e Tributários (Bacia Amazônica, Brasil)

2021 ◽  
Vol 14 (2) ◽  
pp. 997
Author(s):  
Rogério Ribeiro Marinho ◽  
Antonio Fábio Sabbá Guimarães Vieira ◽  
Feliciano De Souza Maciel
Keyword(s):  
Sediment Transport ◽  
River Basin ◽  
Amazon Basin ◽  
Suspended Sediments ◽  
Fine Sand ◽  
Large River ◽  
Coarse Sand ◽  
Sediment Size ◽  
Negro River ◽  
Rio Negro

O conhecimento das características físicas de sedimentos transportados por grandes sistemas fluviais possui significativa importância para o entendimento de processos geomorfológicos e hidrológicos. O nível de conhecimento dos grandes sistemas fluviais da Amazônia e sua relação com o transporte de sedimentos ainda é limitado, resultando em lacunas de conhecimento sobre a dinâmica da paisagem nesta complexa região. Este trabalho teve como objetivo avaliar a distribuição espacial da granulometria de sedimentos de fundo e suspenso do Rio Negro e tributários. Realizou-se análise da distribuição do tamanho dos sedimentos em seções amostrais localizadas no alto, médio e baixo curso do Rio Negro. Os resultados da análise granulométrica da carga de fundo indicam a predominância de sedimentos com tamanho variando de 0,25 a 1,0 mm (principalmente areia fina, areia média e areia grossa) enquanto no baixo curso as amostram oscilaram de areia fina a partículas lamosas (< 0,50 mm). No Rio Negro os sedimentos suspensos são compostos principalmente de partículas finas de silte (90% menor que 80 µm) com diâmetro mediano (D50) de 25 µm. As características granulométricas apresentadas neste trabalho fornecem subsídios para o entendimento de processos hidrodinâmicos de transporte e deposição dos sedimentos de fundo e suspenso neste gigante sistema fluvial.    Upstream-downstream Granulometry Analysis of bed and suspended sediments in the Negro River Basin (Amazon Basin, Brazil)A B S T R A C TThe knowledge of the physical characteristics of sediments transported by large river systems has significant importance for the understanding of geomorphological and hydrological processes. The level of knowledge of the large rivers of the Amazon basin and their relationship with sediment transport is limited, resulting in gaps about the dynamics of the landscape in this complex region. This article analyzes the spatial distribution of granulometry of bed and suspended sediments in the Negro River and tributaries. An analysis of the sediment size distribution was carried out in sample sections located in the upper, middle and lower reaches of the Negro River. The results of the granulometric analysis of the bed load indicate the predominance of sediments with sizes ranging from 0.25 to 1.0 mm (mainly fine sand, medium sand and coarse sand) while in the low course they showed oscillated from fine sand to muddy particles (<0.50 mm). In the Negro River basin the suspended sediments are composed mainly of fine silt particles (90% less than 80 µm) with a median diameter (D50) of 25 µm. The granulometric characteristics presented in this work provide subsidies for the understanding of hydrodynamic processes of transport and deposition of bed and suspended sediments in this huge fluvial system.Keywords: sediment transport, Amazon floodplain, multichannel river, anabranching

scholarly journals CHARACTERISTIC OF SEDIMENT AT LEKOK COASTAL WATERS, PASURUAN REGENCY, EAST JAVA

2020 ◽  
Vol 12 (1) ◽  
pp. 235-246
Author(s):  
Rifka Rimbi Anggraini ◽  
Uun Yanuhar ◽  
Yenny Risjani
Keyword(s):  
Coastal Water ◽  
Coastal Waters ◽  
Sandy Loam ◽  
Gravimetric Method ◽  
Open Water ◽  
Silt Loam ◽  
Sediment Grain Size ◽  
Sediment Distribution ◽  
Sediment Size ◽  
Coastal Changes

Sedimentation is one of the dynamics that occur in coastal areas to determine the condition of the coast. Lekok coastal water is one of the open water areas that have very fluctuating dynamics in coastal changes. The structural study of sediment distribution conducted in this location is used to provide information about the process of transportation and sedimentation based on the distribution of sediment grain size. This study aims to determine the horizontal grain sediment size in the Lekok coastal waters. This research was conducted at nine sampling points by sampling in the form of primary sediments randomly using the grab sampler method. Furthermore, further analysis is done by the gravimetric method. Based on the results of the study note that sediments characteristic in Lekok coastal water are generally dominated by three types of sediments, namely: sandy loam, loam, and silt loam. Sorting values ​​are in a well-sorted to the moderately well-sorted condition where the sediment conditions are well sorted. The skewness value is skewed positively, where the value indicates a positive skewed sedimentary condition. The value of kurtosis is in the leptokurtic condition where the sediment from station 1 to station 9 is homogeneous.

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