Temporal and Spatial Variation of Mixing and Movement of Suspended Sediment in the Macrotidal Chikugo River Estuary

Azhikodan, Gubash; Yokoyama, Katsuhide

doi:10.2112/jcoastres-d-14-00097.1

Cited by 30 publications

(4 citation statements)

References 39 publications

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“…A number of study has reported good relationships among EC, turbidity and SSC in the estuaries. Although the sea surface salinity has no direct color signal, turbidity and SSC have often been observed to be strongly inversely correlated with salinity (Azhikodan and Yokoyama 2015;Oliver et al 2010). The similar results were also obtained in this study (Fig.…”

Section: Ec Estimation Using Sentinel-2supporting

confidence: 91%

Monitoring saline intrusion in the Ayeyarwady Delta, Myanmar, using data from the Sentinel-2 satellite mission

Sakai

Omori

et al. 2021

Paddy Water Environ

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Summer rice cannot be grown near the coast of the Ayeyarwady Delta, Myanmar, because of the high salinity in river water during the dry season. This means that saline intrusion should be monitored to manage the irrigated rice-growing area. The aim of this study therefore is to develop a model to estimate the salinity of river water using satellite imagery. The imagery of Sentinel-2 was suitable for monitoring saline intrusion because of their high spatial (10-m) and temporal (10-day) resolutions. We found that the reflectance of the visible bands was correlated with electrical conductivity, which was influenced by the concentration and composition of dissolved salts. When the river water mixed with the salt water from the sea, suspended particles tended to flocculate and settle, as a result, less turbid water was more saline. The best-fitting model was obtained with the green band (coefficient of determination R2 of 0.776, root mean square error of 4.896 dSm−1, and mean absolute error of 3.340 dS m−1). The saline intrusion showed considerable spatial and temporal variability during the dry season. The salinity intrusion extended approximately 80 km inland at the end of the dry season in March in the Pathein River. The 1 ppt salt concentration line in March marked the boundary between cultivated and non-cultivated areas of paddy field, which indicates that cultivable areas were strongly affected by saline intrusion. The results show that more frequent and higher resolution monitoring than before of the Sentinel-2 can support effective water resource management.

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Section: Ec Estimation Using Sentinel-2supporting

confidence: 91%

Monitoring saline intrusion in the Ayeyarwady Delta, Myanmar, using data from the Sentinel-2 satellite mission

Sakai

Omori

et al. 2021

Paddy Water Environ

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“…Based on mixing characteristics, estuaries can be classified as vertically mixed, slightly stratified, strongly stratified, or saline-wedged. The mixing that occurred in an estuary is crucial for the sediment, nutrient, and pollution distribution in a coastal area [8][9][10][11][12]. Fresh water from the river was less dense than salt water, therefore it was more likely to float on top of the salt water because of its lighter weight.…”

Section: Introductionmentioning

confidence: 99%

Idealised Estuary Salinity-Morphology Effect Characterisation Investigation

Tengku Fadhlin Tengku Mohmed Noor Izam,

Nuryazmeen Farhan Haron,

Siti Nurhayati Mohd Ali

et al. 2024

ARASET

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Estuaries are bodies of water along the coasts that are formed when fresh water from rivers flows into and mixes with salt water from the ocean. The density of seawater is greater than fresh water and it varies with salinity and temperature. Fresh water tends to float on top of seawater because of its lower density. Human-induced activities like the dredging of shipping lanes along the bottom estuarine, the dumping of industrial wastes into the water system, and shoreline development influence estuarine dynamics which include the mixing process. These activities lead to salinity changes and further adversely affect the estuarine ecosystem. The purpose of this research is to verify how salinity-morphology relations change in an estuarine system under various rainfall patterns, more specifically under extremely high rainfall conditions. The experiment that has been conducted studied the salinity-morphology relationships for a variety of rainfall patterns, most particularly for exceptionally high rainfall conditions, using an idealised channel. In the first part of this research, the morphology changes of the mixing between salt water (estuary) and freshwater (river) for different rainfall patterns, had been investigated in laboratory experiments. Fresh water was released from one end of the flume channel and overflowing over the weir at the other end. Meanwhile, salt water was represented by the red dye tracer released slowly through a weir and intruded horizontally to the upstream as a gravity current. In this experiment, an artificial roughened bed section was used as morphology change. The salinity pattern is plotted using Microsoft Excel. The salinity levels were measured at selected stations along the channel/longitudinal (x-axis), and also in transverse (y-axis) and vertical directions (z-axis) within the time duration. The observed salinity profile showed the difference in salinity level between heavy and light rain conditions with morphology effect where during heavy rain, the salinity level will decrease, hence, the existence of an artificial roughened bed section will affect the time taken for the process of mixing between salt water and fresh water.

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“…Os estuários são uma zona de transição entre os ambientes marinho e de água doce que apresenta uma variação dos gradientes ambientais, espacial e temporalmente, o que os torna um ambiente dinâmico e complexo (Azhikodan & Yokoyama, 2015). Os estuários em todo o mundo tornaram-se substancialmente influenciados por atividades humanas, incluindo mudanças no uso da terra, eutrofização e derramamentos de óleo, que afetam a composição e a diversidade dos organismos através de fatores abióticos e bióticos (Wetzel, 2001).…”

Section: Introductionunclassified

DIATOMÁCEAS CÊNTRICAS (Coscinodiscophyceae e Mediophyceae) PLANCTÔNICAS EM DOIS ESTUÁRIOS TROPICAIS BRASILEIROS: LEVANTAMENTO FLORÍSTICO E NOVOS REGISTROS

Moura

Diniz

Amorim

et al. 2022

ACMAR

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Os estuários são ecossistemas altamente produtivos e dinâmicos, sendo o fitoplâncton o principal produtor primário, e as diatomáceas cêntricas são o grupo mais abundante observado no fitoplâncton marinho e estuarino. Nesse contexto, o objetivo deste estudo foi realizar o levantamento taxonômico das diatomáceas cêntricas planctônicas(Coscinodiscophyceae e Mediophyceae) de dois estuários tropicais localizados no Nordeste do Brasil. O estudo foi realizado antes do maior impacto de derramamento de óleo ocorrido no Brasil em 2019. Trinta e seis táxons foram identificados. Mediophyceae foi a classe mais representativa, com 24 espécies. Coscinodiscus foi o gênero com maior número de espécies identificadas, seguido de Chaetoceros e Thalassiosira. A espécie Chaetoceros filiferus Karsten foi reportada pela primeira vez para o Brasil, enquanto Paralia fenestrata (Sawai & Nagumo) e Shionodiscus endoseriatus (Hasle & Fryxell) Alverson consistem em novos registros para o Nordeste do Brasil e Thalassiosira lineata Jousé para o estado de Pernambuco. Descrições, ilustrações e comentários sobre as variações morfológicas e métricas dos táxons foram apresentados. Os resultados evidenciam a importância de estudos florísticos para oconhecimento da flora de diatomáceas de ambientes marinhos tropicais, além de servir como um estudo de base para trabalhos futuros nos estuários estudados. Palavras-chave: Brasil, diatomáceas marinhas, fitoplâncton, microscopia eletrônica de varredura, taxonomia

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Temporal and Spatial Variation of Mixing and Movement of Suspended Sediment in the Macrotidal Chikugo River Estuary

Cited by 30 publications

References 39 publications

Monitoring saline intrusion in the Ayeyarwady Delta, Myanmar, using data from the Sentinel-2 satellite mission

Monitoring saline intrusion in the Ayeyarwady Delta, Myanmar, using data from the Sentinel-2 satellite mission

Idealised Estuary Salinity-Morphology Effect Characterisation Investigation

DIATOMÁCEAS CÊNTRICAS (Coscinodiscophyceae e Mediophyceae) PLANCTÔNICAS EM DOIS ESTUÁRIOS TROPICAIS BRASILEIROS: LEVANTAMENTO FLORÍSTICO E NOVOS REGISTROS

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