Động lực phát triển vùng cửa Sông Hậu (cửa Định An - Tranh Đề)

2008 ◽  
Vol 30 (2) ◽  
pp. 130-135
Author(s):  
Hoa Mạnh Hùng ◽  
Nguyễn Quang Thành ◽  
Phan Thị Thanh Hằng
Keyword(s):  
River Estuary ◽  
River Mouth

Evaluating the dynamics of the Hau River estuary (Dinh An - Tranh De river mouth)

scholarly journals Tidal current energy potential of Nalón river estuary assessment using a high precision flow model

2018 ◽  
Vol 8 (1) ◽  
pp. 118-123
Author(s):  
Nicolás Badano ◽  
Rodolfo Espina Valdés ◽  
Eduardo Álvarez Álvarez
Keyword(s):  
High Precision ◽  
Hydrodynamic Model ◽  
Tidal Current ◽  
Flow Model ◽  
River Estuary ◽  
River Mouth ◽  
Hydrodynamic Models ◽  
Energy Potential ◽  
Tidal Current Energy ◽  
Current Energy

Abstract Obtaining energy from tide currents in onshore locations is of great interest due to the proximity to the points of consumption. This opens the door to the feasibility of new installations based on hydrokinetic microturbines even in zones of moderate speed. In this context, the accuracy of energy predictions based on hydrodynamic models is of paramount importance. This research presents a high precision methodology based on a multidimensional hydrodynamic model that is used to study the energetic potential in estuaries. Moreover, it is able to estimate the flow variations caused by microturbine installations. The paper also shows the results obtained from the application of the methodology in a study of the Nalón river mouth (Asturias, Spain).

Evaluation of the Status of Copper Contamination of Surface Sediments of Jen-Gen River Estuary, Taiwan

2013 ◽  
Vol 300-301 ◽  
pp. 1381-1384
Author(s):  
Cheng Di Dong ◽  
Yao Ting Tu ◽  
Chiu Wen Chen ◽  
Chih Ming Kao ◽  
Chih Feng Chen
Keyword(s):  
Municipal Wastewater ◽  
Surface Sediments ◽  
Biological Effects ◽  
Sediment Quality ◽  
River Estuary ◽  
River Mouth ◽  
Moderate Degree ◽  
River Bank ◽  
Biological Damage ◽  
Severe Degree

Major objectives of this study are to evaluation the enrichment, accumulation, and potential biological effects of copper (Cu) in the surface sediments of Jen-Gen River estuary, Taiwan. Eleven sampling locations were installed near the mouth of Jen-Gen River to collect sediment samples for analyzing Cu. Results of laboratory analyses show that concentrations of Cu in the sediments are between 67 and 278 mg/kg with an average of 181±61 mg/kg. The spatial distribution of Cu reveals that the Cu concentration is relatively high in the boundary of the river estuary. This indicates that upstream industrial and municipal wastewater discharges along the river bank are major sources of pollution. Results from the enrichment factor (EF) analysis imply that the sediments can be characterized as minor to moderately severe degree of Cu enrichment. Results of geo-accumulation index (Igeo) analysis indicate that the sediments can be characterized as none to moderate degree of Cu accumulation. Base on the comparison with sediment quality guidelines (SQGs), the concentrations of Cu in Jen-Gen River mouth sediments may cause acute biological damage.

Pulsed terrestrial organic carbon persists in an estuarine environment after major storm events

2020 ◽  
Author(s):  
Eero Asmala ◽  
Christopher Osburn ◽  
Ryan Paerl ◽  
Hans Paerl
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
River Estuary ◽  
River Mouth ◽  
Neuse River Estuary ◽  
Storm Events ◽  
Dynamic Component ◽  
Neuse River ◽  
Doc Concentration ◽  
A Minor

<p>The transport of dissolved organic carbon from land to ocean is a large and dynamic component of the global carbon cycle. Export of dissolved organic carbon from watersheds is largely controlled by hydrology, and is exacerbated by increasing major rainfall and storm events, causing pulses of terrestrial dissolved organic carbon (DOC) to be shunted through rivers downstream to estuaries. Despite this increasing trend, the fate of the pulsed terrestrial DOC in estuaries remains uncertain. Here we present DOC data from 1999 to 2017 in Neuse River Estuary (NC, USA) and analyze the effect of six tropical cyclones (TC) during that period on the quantity and fate of DOC in the estuary. We find that that TCs promote a considerable increase in DOC concentration near the river mouth at the entrance to the estuary, on average an increase of 200 µmol l<sup>-1</sup> due to storms was observed. TC-induced increases in DOC are apparent throughout the estuary, and the duration of these elevated DOC concentrations ranges from one month at the river mouth to over six months in lower estuary. Our results suggest that despite the fast mineralization rates, the terrestrial DOC is processed only to a minor extent relative to the pulsed amount entering the estuary. We conclude that the vast quantity of organic carbon delivered to estuaries by TCs transform estuaries from active biogeochemical processing “reactors” of organic carbon to appear more like passive shunts due to the sheer amount of pulsed material rapidly flushed through the estuary.</p>

Movements of Sockeye Salmon (Oncorhynchus nerka) in the Skeena River Estuary as Revealed by Ultrasonic Tracking

1975 ◽  
Vol 32 (2) ◽  
pp. 233-242 ◽  
Author(s):  
C. Groot ◽  
K. Simpson ◽  
I. Todd ◽  
P. D. Murray ◽  
G. A. Buxton
Keyword(s):  
Tidal Cycle ◽  
Sockeye Salmon ◽  
Salt Water ◽  
Oncorhynchus Nerka ◽  
River Estuary ◽  
River Mouth ◽  
Tidal Flows ◽  
Skeena River ◽  
Ultrasonic Tracking ◽  
Passive Movements

Movements of adult sockeye salmon (Oncorhynchus nerka) entering the Skeena River were examined in 1969 and 1970 by ultrasonic tracking methods. Fifteen of 18 sockeye released in the lower river seemed to move passively in and out with flood and ebb streams. Two fish moved upstream independent of tides and one salmon swam against ebb and flood currents. Ground speeds in both years of operation were 1.6 km/h during rising and 2.1 km/h during falling tides, causing the fish to be transported downstream by about 3 km per tidal cycle. Three salmon released outside the river mouth in salt water also seemed to ride the tidal flows passively. Ground speeds during ebb (3.6 km/h) were again greater than during flood (2.0 km/h), indicating a net offshore movement. We conclude that these passive movements are not an artifact but that sockeye salmon normally slow down or pause upon reaching the "home river" and drift for a period in tidal currents in the estuary and river mouth before migrating upstream.

scholarly journals Investigation of Morphological Changes in the Tamsui River Estuary Using an Integrated Coastal and Estuarine Processes Model

Water ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 1084 ◽  
Author(s):  
Tung-Chou Hsieh ◽  
Yan Ding ◽  
Keh-Chia Yeh ◽  
Ren-Kai Jhong
Keyword(s):  
Sandy Beach ◽  
Morphological Changes ◽  
River Estuary ◽  
River Mouth ◽  
Physical Processes ◽  
Complex Flow ◽  
Monsoon Period ◽  
Estuarine Processes ◽  
Sediment Flushing ◽  
The Impact

This study is to investigate morphological changes in the Tamsui River Estuary in Taiwan driven by multiple physical processes, such as river flows, tides, waves, and storm surges, and then to study the impacts of sediment flushing operated at the Shihmen reservoir upstream on the river estuary. An integrated coastal and estuarine processes model (CCHE2D-Coast) (Center for Computational Hydroscience and Engineering Two-Dimensional-Coast) was validated by simulating these physical processes in the estuary driven by three historical typhoons in 2008. The site-specifically validated model was then applied to simulate morphological changes in the estuary in response to reservoir sediment flush scenarios from the upstream. For the impact assessment of sediment flushing, a synthetic hydrological event was designed by including a historical typhoon and a typical monsoon. It was found that during the typhoon, the sediments will be mostly deposited in the estuarine river reach of Tamsui and the Wazihwei sandy beach. During the monsoon period, most of the sediments tend to be deposited in the second fishing port of Tamsui, the northern breakwater, and the estuary, while the Wazihwei sandy beach in the river mouth would be scoured by backflow. Simulations of the complex flow fields and morphological changes will facilitate the best practice of sediment management in the coastal and estuarine regions.

scholarly journals KONTRIBUSI USAHA TRANSPORTASI “OJEK PERAHU” TERHADAP PENDAPATAN RUMAH TANGGA DI KELURAHAN SINDULANG KECAMATAN TUMINTING KOTA MANADO

2019 ◽  
Vol 6 (12) ◽  
Author(s):  
Fernanda Grasela Ruauw ◽  
Jardie A. Andaki ◽  
Grace O. Tambani
Keyword(s):  
Data Analysis ◽  
Household Income ◽  
Family Income ◽  
Statistical Tests ◽  
River Estuary ◽  
River Mouth ◽  
Study Data ◽  
Analysis Techniques ◽  
Total Household Income ◽  
Motorcycle Taxi

AbstractBoats are the choice for transportation activities on the river. The condition of the Tondano River, specifically at the river mouth is suitable for boat crossings. The need to move from one side of the river to the other side of the river with various needs, raises remuneration for "mining" boats / ojek boats. Opinions generated from this remuneration contribute to family income.The objectives of this study, namely: 1) identify the activities of "mining" boat / ojek boat transportation in the Tondano River Estuary of Manado City; and 2) determine the contribution of "mining" boat / ojek boat transportation activities in the Tondano River Estuary of Manado City to family income.The subjects of this study were the people in Sindulang I and Sindulang II Subdistrict Tuminting Sub-District, Manado City who carried out the business of "mining" boats / ojek boats. While the objects in this study were household income in Sindulang I Village and Sindulang II Tuminting District, Manado City.Analysis technique is an attempt to determine the answer to the question about the formula and the things obtained in a study. Data that has been entered and collected is analyzed to answer the research objectives. Data analysis techniques are adjusted to the research objectives. The data analysis techniques used in this study are as follows:Analysis of the contribution of boat mining / ojek boat businesses to total household income is carried out by the percentage method. Contributions are contributions that can be given by something to other things. The data obtained were analyzed without statistical tests by calculating the amount of money obtained from a business activity "boat mining" / ojek boat and total household income multiplied by one hundred percent.The results of the research and discussion can be concluded: 1) boat motorcycle taxi activities carried out in the form of ferry services and boat rental services for use as a means of fishing or fishing activities; 2) the contribution of boat motorcycle taxis to family income is 81.97%, while the remaining 18.03% is contributed by other businesses outside the boat ojek business; 3) outpouring of work time causes the contribution of boat motorcycle taxis to be greater than the contribution of other businesses outside the boat ojek business.Keywords: transportation, boat motorcycle taxi, activities, contributions AbstrakPerahu menjadi pilihan untuk aktivitas transportasi di sungai. Kondisi Sungai Tondano, khusus pada muara sungai cocok untuk penyeberangan menggunakan perahu. Kebutuhan untuk berpindah dari satu sisi sungai menuju sisi lain dari sungai dengan berbagai keperluan, menimbulkan balas jasa bagi perahu “tambangan” / ojek perahu. Pendapat yang dihasilkan dari balas jasa ini berkontribusi terhadap pendapatan keluarga. Tujuan dari penelitian ini, yaitu : 1) mengidentifikasi aktivitas transportasi perahu “tambangan” / ojek perahu di Muara Sungai Tondano Kota Manado; dan 2) menentukan kontribusi aktivitas transportasi perahu “tambangan” / ojek perahu di Muara Sungai Tondano Kota Manado terhadap pendapatan keluarga.Subjek penelitian ini adalah masyarakat di Kelurahan Sindulang I dan Sindulang II Kecamatan Tuminting Kota Manado yang menjalankan kegiatan usaha perahu “tambangan” / ojek perahu. Sedangkan objek dalam penelitian ini adalah pendapatan rumah tangga di Kelurahan Sindulang I dan Sindulang II Kecamatan Tuminting Kota Manado.Teknik analisis merupakan suatu usaha untuk menentukan jawaban atas pertanyaan tentang rumusan dan hal-hal yang diperoleh dalam suatu penelitian. Data yang sudah masuk dan terkumpul dianalisis ubtuk menjawab tujuan penelitian. Teknik analisis data disesuaikan dengan tujuan penelitian. Adapun teknik analisis data yang digunakan dalam penelitian ini adalah sebagai berikut:Analisis kontribusi usaha perahu “tambangan” / ojek perahu terhadap pendapatan total rumah tangga dilakukan dengan metode persentase. Kontribusi adalah sumbangan yang dapat diberikan oleh suatu hal terhadap hal lain. Data yang diperoleh dianalisis tanpa uji statistik dengan menghitung jumlah uang yang diperoleh dari suatu kegiatan usaha perahu “tambangan” / ojek perahu dan pendapatan total rumah tangga dikali seratus persen.Hasil penelitian dan pembahasan dapat ditarik kesimpulan: 1) aktivitas ojek perahu dilakukan dalam bentuk jasa penyeberangan dan jasa sewa perahu untuk penggunaan sebagai sarana aktivitas pemancingan atau mencari ikan; 2) kontribusi usaha ojek perahu terhadap pendapatan keluarga sebesar 81,97%, sedangkan sisanya 18,03% dikontribusi dari usaha lain di luar usaha ojek perahu; 3) curahan waktu kerja menyebabkan kontribusi pendapatan ojek perahu lebih besar dari kontribusi usaha lain di luar usaha ojek perahu.Kata kunci : transportas, ojek perahu, aktivitas, kontribusi

Two-layer hydraulics at the river–ocean interface

2018 ◽  
Vol 856 ◽  
pp. 633-672 ◽  
Author(s):  
Anthony R. Poggioli ◽  
Alexander R. Horner-Devine
Keyword(s):  
Free Surface ◽  
Near Field ◽  
Full Range ◽  
River Estuary ◽  
Surface Profile ◽  
River Mouth ◽  
River Plume ◽  
Gravitational Acceleration ◽  
Wide Range ◽  
Experimental Apparatus

Liftoff is the hydraulically forced detachment of buoyant freshwater from the channel bottom or seabed that occurs as river water discharges into the coastal ocean. It is a key feature of strongly stratified systems, occurring well upstream in the channel or seaward of the river mouth under sufficiently strong forcing. We present a two-layer hydraulic solution for the river–ocean interface that considers the river, estuary and near-field river plume as a single interlinked system, extending previous work that considered them separately. This unified approach provides a prediction of the liftoff location and free-surface profile for a wide range of forcing conditions, which are characterized in terms of the freshwater Froude number $F_{f}\equiv Q/b_{0}\sqrt{g_{0}^{\prime }h_{0}^{3}}$. Here, $Q$ is the river discharge, $b_{0}$ is the channel width, $g_{0}^{\prime }\equiv (\unicode[STIX]{x0394}\unicode[STIX]{x1D70C}_{0}/\unicode[STIX]{x1D70C}_{2})g$ is the reduced gravitational acceleration, $\unicode[STIX]{x0394}\unicode[STIX]{x1D70C}_{0}$ is the density contrast between fresh and ocean water and $h_{0}$ is the total water depth at the river mouth. The solution is validated with laboratory experiments using an experimental apparatus consisting of a long, sloping river channel that discharges into a deep, wide saltwater basin. The experiments simulate the full range of hydraulic behaviours predicted by the model, from saltwater intrusion to offshore liftoff. For $F_{f}<1$, liftoff occurs in the estuary channel and our results show that the relationship between intrusion length and $F_{f}$ depends on the channel slope. For $F_{f}>1$, corresponding to flood conditions in many natural systems, liftoff is forced outside the river mouth and the hydraulic coupling between the channel and shelf becomes more important. For these conditions and for intermediate to steeply sloped shelves, the offshore liftoff distance varies linearly with $F_{f}-1$, a particularly simple scaling given the nonlinearity and relative complexity of the governing equations. The model and experimental results support a conceptual description of the river–ocean interface that relates the liftoff location, free-surface elevation and the spreading rate of the buoyant river plume.

scholarly journals HYDROCHEMICAL STUDIES OF THE PARTIZANSKAYA RIVER ESTUARY (NAKHODKA BAY, JAPAN SEA) IN SUMMER SEASON OF LOW WATER DISCHARGE

2018 ◽  
Vol 193 ◽  
pp. 143-152 ◽  
Author(s):  
P. Yu. Semkin ◽  
P. A. Tishchenko ◽  
T. A. Mikhailik ◽  
Yu. A. Barabanshchikov ◽  
G. Yu. Pavlova ◽  
...  
Keyword(s):  
River Water ◽  
Salt Water ◽  
Water Discharge ◽  
Chlorophyll Concentration ◽  
River Estuary ◽  
River Mouth ◽  
Japan Sea ◽  
Bottom Layer ◽  
Autochthonous Organic Matter ◽  
Limited Water Exchange

Chemical water parameters in the Partizanskaya River estuary were measured on July 18–19, 2012 in conditions of low water discharge (20.1 m3 /s). In these conditions, the cline of salt water at the bottom penetrated up to 11 km upstream from the river mouth and the fresh river water passed the estuarine zone of mixing in approximately 2 days. Salt composition of the mixed water in the estuary had conservative dependence on salinity. By dynamical signs, the estuary could be divided into two zones: i) zone of active exchange between the surface freshwater layer and the bottom salted layer on the distance 5.5 km from the river mouth to the first sandy riverbank that the fresh river water passed in 12 hours, and ii) the upper part of the estuary with limited water exchange. The complex of water environments in the estuary, as good water transparency, strong stratification, and high concentrations of terrestrial nutrients, was favorable for phytoplankton blooming, so the chlorophyll concentration in the estuarine waters exceeded 40 μg/L. Destruction of autochthonous organic matter caused anomalies in distribution of carbonate and nutrient parameters and was accompanied by hypoxia in the bottom layer with the dissolved oxygen content lowering to 61 μM/kg.

Enrichment and Accumulation of Zinc in the Sediment of Jen-Gen River Estuary, Taiwan

2012 ◽  
Vol 610-613 ◽  
pp. 2693-2696
Author(s):  
Cheng Di Dong ◽  
Chih Feng Chen ◽  
Chiu Wen Chen
Keyword(s):  
Spatial Distribution ◽  
Municipal Wastewater ◽  
Sediment Quality ◽  
River Estuary ◽  
River Mouth ◽  
River Bank ◽  
Biological Damage ◽  
Sources Of Pollution ◽  
Quality Guidelines ◽  
Accumulation Index

The spatial distribution, enrichment, and accumulation of zinc (Zn) in the surface sediments of Jen-Gen River estuary, Taiwan, were studied. Results show that samples collected from 11 stations near the estuary of Jen-Gen River contain 221–627 mg/kg of Zn with average of 502±114 mg/kg. The spatial distribution of Zn reveals is relatively high in the river mouth region, and gradually diminishes toward the harbor region. This indicates that upstream industrial and municipal wastewater discharges along the river bank are major sources of pollution. Enrichment factor analysis indicates that the sediments of Jen-Gen River estuary were severe enrichment with Zn. Geo-accumulation index analysis indicates that the sediments of Jen-Gen River estuary were moderately strong accumulated with Zn. Base on the comparison with sediment quality guidelines (SQGs), the concentrations of Zn in the sediments of Jen-Gen River estuary may cause acute biological damage.

scholarly journals Cladocerans (Branchiopoda) of a tropical estuary in Brazil

2005 ◽  
Vol 65 (1) ◽  
pp. 107-115 ◽  
Author(s):  
M. N Paranaguá ◽  
S Neumann-Leitão ◽  
J. D Nogueira-Paranhos ◽  
T. A. Silva ◽  
T. Matsumura-Tundisi
Keyword(s):  
Rainy Season ◽  
High Tide ◽  
River Estuary ◽  
River Mouth ◽  
Mesh Size ◽  
Marine Species ◽  
Wide Distribution ◽  
Average Density ◽  
Chemical Pollution ◽  
Tropical Estuary

The study was conducted in the Capibaribe river estuary in Recife (Brazil) to assess the role played by cladocerans in a eutrophic environment. Samplings were carried out monthly at 4 fixed stations along the estuary from July 1987 to June 1988. Collections were made with a plankton net of 65 micrometers mesh size. Six cladocerans species were registered: Penilia avirostris, Diaphanosoma spinulosum, Chydorus barroisi, Ceriodaphnia rigaudi, Ilyocryptus spinifer, and Moina micrura. The most frequent species was Moina micrura with 49%. The only true marine species was Penilia avirostris, which was registered at station 1 (close to the river mouth), during high and low tide and in the dry season. The Cladocera average density decreased from 329 ind.m-3 (August 1987, high tide) to 2 ind.m-3 (March 1988, high tide) due to the high load of organic and chemical pollution received by the estuary. At all stations, D. spinulosum, M. micrura, and C. barroisi occurred with a wide distribution, mainly during the rainy season. C. rigaudi and I. spinifer were rare, occurring only during the rainy season. Cladocerans played an important role in the food webs of the plankton community of the Capibaribe tropical estuary and the dominance of a few small species indicated a hypereutrophic environment. A high level of disturbance was indicated by the decline in diversity of specialized species and the increase in abundance of opportunistic species like M. micrura.

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