scholarly journals Modelling Study of Transport Time Scales for a Hyper-Tidal Estuary

Water ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2434
Author(s):  
Guanghai Gao ◽  
Junqiang Xia ◽  
Roger A. Falconer ◽  
Yingying Wang
Keyword(s):  
Numerical Model ◽  
Water Level ◽  
Residence Time ◽  
Exposure Time ◽  
Neap Tide ◽  
Spring Tide ◽  
High Water ◽  
Residence Times ◽  
Severn Estuary ◽  
Release Times

This paper presents a study of two transport timescales (TTS), i.e., the residence time and exposure time, of a hyper-tidal estuary using a widely used numerical model. The numerical model was calibrated against field measured data for various tidal conditions. The model simulated current speeds and directions generally agreed well with the field data. The model was then further developed and applied to study the two transport timescales, namely the exposure time and residence time for the hyper-tidal Severn Estuary. The numerical model predictions showed that the inflow from the River Severn under high flow conditions reduced the residence and exposure times by 1.5 to 3.5% for different tidal ranges and tracer release times. For spring tide conditions, releasing a tracer at high water reduced the residence time and exposure time by 49.0% and 11.9%, respectively, compared to releasing the tracer at low water. For neap tide conditions, releasing at high water reduced the residence time and exposure time by 31.6% and 8.0%, respectively, compared to releasing the tracer at low water level. The return coefficient was found to be vary between 0.75 and 0.88 for the different tidal conditions, which indicates that the returning water effects for different tidal ranges and release times are all relatively high. For all flow and tide conditions, the exposure times were significantly greater than the residence times, which demonstrated that there was a high possibility for water and/or pollutants to re-enter the Severn Estuary after leaving it on an ebb tide. The fractions of water and/or pollutants re-entering the estuary for spring and neap tide conditions were found to be very high, giving 0.75–0.81 for neap tides, and 0.79–0.88 for spring tides. For both the spring and neap tides, the residence and exposure times were lower for high water level release. Spring tide conditions gave significantly lower residence and exposure times. The spatial distribution of exposure and residence times showed that the flow from the River Severn only had a local effect on the upstream part of the estuary, for both the residence and exposure time.

scholarly journals SALINITY INTRUSION IN THE GUAPIMIRIM ESTUARY, RIO DE JANEIRO STATE, BRAZIL

2014 ◽  
Vol 32 (1) ◽  
pp. 161 ◽  
Author(s):  
Gustavo Vaz de Melo ◽  
José Antonio Baptista Neto ◽  
Susana Beatriz Vinzón ◽  
Allan Sandez de Oliveira ◽  
Michel Arthur Faria Vicente ◽  
...  
Keyword(s):  
Water Column ◽  
Residence Time ◽  
Neap Tide ◽  
Spring Tide ◽  
High Water ◽  
Freshwater Discharge ◽  
Salinity Intrusion ◽  
Rainy Period ◽  
Meandering Channel ◽  
Column Structure

ABSTRACT. This work was conducted in the Guapimirim estuary, the main tributary of the Guanabara Bay. This system is located in a preserved area in the catchmentbasin of the bay, inside the Guapimirim Environmental Protection Area. The estuary presents a meandering channel with 3 meters mean depth. The aim of thiswork is to evaluate the salinity intrusion dynamics in response to the tide and freshwater discharge, as well as its effects on the water column structure and residencetime. Surveys were performed to assess the salinity structure along the estuary main channel under different freshwater discharges (dry and rainy period) and tide (neapand spring). The results showed significant differences in the water column structure, presenting high stratification in neap tide and conditions homogeneous in springtide. The salinity front (SF) showed a bigger displacement in the spring tide. Under highly stratified conditions, in neap tide, its displacement was bigger with smallertidal amplitude. The location of SF inside of the estuary, in the high water, was influenced manly by freshwater discharge. The residence time in the Guapimirim estuarywas longer in neap tide and dry period, presenting a good relationship with freshwater discharge.Keywords: Guapimirim estuary, salinity intrusion, residence time. RESUMO. Este trabalho foi desenvolvido no estuário de Guapimirim, principal tributário da Baía de Guanabara. Este sistema se localiza em uma área ainda preservadana bacia de drenagemda baía, dentro da Área de Proteção Ambiental de Guapimirim. O estuário apresenta um canal meandrante com uma profundidade média de 3 metros. O objetivo deste trabalho consiste em avaliar a dinâmica da intrusão salina em resposta a atuação dos processos físicos como a vazão fluvial e a maré, assimcomo, sua consequência na estrutura da coluna d’água e tempo de residência. Foram realizados levantamentos sobre a estrutura salina ao longo do canal principal doestuário em diferentes condições de vazão fluvial (período seco e chuvoso) e maré (quadratura e sizígia). Os resultados mostraram diferenças marcantes na estrutura dacoluna d’´agua sendo estratificado em maré de quadratura e mais homogêneo em maré de sizígia. A frente salina apresentou um maior deslocamento em maré de sizígia.Em condições de alta estratificação, em maré de quadratura, o maior deslocamento da frente salina esteve associado a uma menor amplitude da maré. A vazão fluvial foio principal processo físico que atuou no alcance máximo da frente salina. O tempo de residência de uma parcela de água dentro do estuário de Guapimirim foi maiorem condição de maré de quadratura e em período seco, apresentando boa relação com a vazão fluvial.Palavras-chave: estuário de Guapimirim, intrusão salina, tempo de residência.

scholarly journals Comparison of empirical models with intensively observed data for prediction salt intrusion in the Sumjin River estuary, Korea

2009 ◽  
Vol 6 (2) ◽  
pp. 1879-1905 ◽  
Author(s):  
D. C. Shaha ◽  
Y.-K. Cho
Keyword(s):  
River Discharge ◽  
Neap Tide ◽  
Spring Tide ◽  
River Estuary ◽  
High Water ◽  
Empirical Models ◽  
Length Scale ◽  
Salt Intrusion ◽  
Salinity Data ◽  
Comparative Results

Abstract. Intensive measurements of salt intrusion in the Sumjin River estuary were taken at high and low waters during both spring and neap tides in each season from August 2004 to April 2007. The estuary demonstrated partially- and well-mixed characteristics during the spring tide and stratified condition during the neap tide. The salt intrusion at high water varied from about 13.39 km in summer 2005 to 25.62 km in autumn 2006. The salt intrusion depended primarily on the freshwater discharges rather than those of spring-neap tidal oscillations. Analysis of three years of observed salinity data indicated that the salt intrusion length scale in the Sumjin River estuary was proportional to the river discharge to the −1/5 power. Five empirical models were applied to the Sumjin River estuary to explore the most suitable as an easy-to-use tool for prediction of the salt intrusion length as functions of the geometry, river discharge and tide. Comparative results showed that the Nguyen and Savenije (2006) model developed under both partially- and well-mixed estuaries yielded the most satisfactory results of all the models studied for computing the salt intrusion length in the Sumjin River estuary. Our study suggests that the model can generate reasonable results for stratified conditions also.

scholarly journals PENDANGKALAN ALUR PELAYARAN DI PELABUHAN PULAU BAAI BENGKULU

2016 ◽  
Vol 1 (3) ◽  
Author(s):  
Lukman Arifin ◽  
Juniar P. Hutagaol ◽  
Mustafa Hanafi
Keyword(s):  
Water Level ◽  
Current Velocity ◽  
Sea Water ◽  
Neap Tide ◽  
Spring Tide ◽  
Current Measurement ◽  
Geophysical Survey ◽  
Measurement Result ◽  
Level Difference ◽  
Sea Current

Alur pelayaran di Pelabuhan Pulau Baai Bengkulu selalu mengalami pendangkalan. Untuk mengetahui penyebab pendangkalan tersebut maka akan diberikan beberapa informasi hasil kajian geofisika kelautan dari beberapa metoda. Metoda tersebut terdiri dari pengukuran kedalaman laut, pengukuran arus dan pasang surut. Hasil pengukuran kedalaman laut memperlihatkan bahwa kedalaman yang paling dalam di bagian kolam pelabuhan adalah sekitar 12 meter dan yang terdalam di daerah alur juga 12 meter. Pengukuran arus laut memperlihatkan bahwa kecepatan arus pada saat pasang tertinggi lebih tinggi daripada kecepatan arus pada saat surut terendah. Pengendapan lebih besar terjadi pada saat air pasang, apalagi ditambah dengan adanya arus sepanjang pantai yang membawa sedimen ke arah alur. Tipe pasang surut laut di pelabuhan ini adalah tipe campuran ganda, artinya pasang dan surut akan terjadi sekali atau dua kali dalam sehari. Adapun perbedaan tinggi muka air pada saat air pasang dan saat air surut adalah 1,53 meter. Shoaling always occurs in the sailing channel of Pulau Baai Bengkulu Harbour. To know the reason of the shoaling, some information based on the result, of the analysis of several methods of marine geophysical survey are therefore presented. The methods are echo-sounding, sea current and tide measurement. Result of sounding shows that the deepest depth in the lagoon area is around 12 metres and the depth in the channel area is also 12 metres. Result of sea current measurement shows that current velocity during the spring tide is higher than the velocity during the neap tide. Sedimentation is higher in the spring tide, moreover it is increased by the existence of long shore current which transport the sediments into the channel. The type of the sea tide in the harbour is a mixed semi diurnal type which means that the spring and the neap will occur once or twice a day. The height of sea water level difference between spring tide and neap tide season is 1.53 metres.

scholarly journals Hydro-Sedimentary Study of a Tidal River: Case Study of the Arvand River in Iran

2021 ◽  
Vol 11 (1) ◽  
pp. 9-16
Author(s):  
M. Bakhtiari ◽  
A. Ashtari Larki ◽  
A. Samer
Keyword(s):  
Electrical Conductivity ◽  
Field Study ◽  
Water Level ◽  
Neap Tide ◽  
Spring Tide ◽  
Suspended Sediments ◽  
Tidal River ◽  
Deep Distribution ◽  
Suspended Sediments Concentration

Abstract The present field study investigated hydraulic and sediment in tidal conditions. Measurements were made for two stations at neap tide and spring tide for 13-hour periods at no-dimensional depths of 0.2, 0.6 and 0.8 of the water level each time. In these measurements, the parameters of velocity, direction of flow, electrical conductivity, temperature and depth were measured directly, and to determine the amount of suspended sediments per hour, 3 samples of one litre from the mentioned depths were measured by the instantaneous vertical sampler and taken to a laboratory. An examination of the depth charts of the suspended sediments concentration for all stations, and in both the neap tide and the spring tide, showed that, in general the suspended sediments concentration increased with increasing depth. Moreover, the deep distribution of sediments concentration showed that the values obtained in the laboratory corresponded well with the values calculated from the Rouse equation, and as the depth increases, the sediments concentration usually increases.

scholarly journals ESTIMATION OF TIDAL EXCURSION LENGTH ALONG THE SHATT AL-ARAB ESTUARY, SOUTHERN IRAQ

2021 ◽  
Vol 59 (1) ◽  
pp. 79
Author(s):  
Ali Lafta
Keyword(s):  
Water Level ◽  
Neap Tide ◽  
Spring Tide ◽  
Field Measurements ◽  
Site Specific ◽  
Estuary Mouth ◽  
Tidal Excursion ◽  
Mathematical Relation ◽  
Southern Iraq

The tidal excursion length along the Shatt Al-Arab estuary was estimated based on the mathematical relation proposed by Parsa and Shahidi (2010). The field measurements of water level, bathymetry, and discharges were conducted to fulfill the objective of the study. The results revealed that the tidal excursion length is site-specific and depends on the characteristics of location which include tidal phases, bathymetry, and geometry. However, the results indicated that there are pronounced differences in tidal excursions lengths between the spring and neap tide phases in all studies stations. The spring tide coincided with the maximum tidal excursion lengths in Shatt Al-Arab estuary with 16.537, 16.187, 11.122, and 9.139 km in the estuary mouth, Faw, Siba, and Abo Flous stations respectively. While the neap tidal excursion lengths were 12.298, 9.254, and 7.269 km in Faw, Siba, and Abo Flous stations respectively.

Tree-climbing behaviour of Cerithidea decollata, a western Indian Ocean mangrove gastropod (Mollusca: Potamididae)

2006 ◽  
Vol 86 (6) ◽  
pp. 1429-1436 ◽  
Author(s):  
Marco Vannini ◽  
Rocco Rorandelli ◽  
Outi Lähteenoja ◽  
Elisha Mrabu ◽  
Sara Fratini
Keyword(s):  
Indian Ocean ◽  
Neap Tide ◽  
High Tide ◽  
Spring Tide ◽  
Western Indian Ocean ◽  
High Water ◽  
Avicennia Marina ◽  
Single Individual ◽  
Night Time ◽  
Mangrove Tree

The behaviour of Cerithidea decollata, a common western Indian Ocean mangrove tree climbing gastropod, was studied in Mida Creek, Kenya. At the study site, this snail mainly lived in Avicennia marina dominated areas, i.e. in the mangrove belt between high water spring tide and high water neap tide levels. Not a single individual was found on the less common mangrove tree Lumnitzera racemosa, living just above the A. marina level (together with terrestrial grass), and was very rarely recorded on the common Rhizophora mucronata, bordering the seaward side of the A. marina belt. No significant gradient of C. decollata density was found within the whole 150–200 m wide belt. The majority of C. decollata rested on tree trunks during high tide, creeping on the mud flat below the tree for part of low tide, and returning on the trunks well before being reached by the water. This migratory pattern was more evident at spring than at neap tide, at day than at night time and it was strongly influenced by the shore level of the mangrove zone in which animals resided. While C. decollata from lower shore levels neatly massively migrated twice a day, individuals from upper levels showed a more continuous and irregular activity, sometimes crawling on the mud even at high water of spring tide, when they experience just a few centimetres of water for no more than one to two hours.

scholarly journals PERUBAHAN TERJADINYA PUNCAK PASANG SURUT SUNGAI BARITO AKIBAT PEMANASAN GLOBAL

INFO-TEKNIK ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 71
Author(s):  
Holdani Kurdi ◽  
Ulfa Fitriati ◽  
M. Ainun Najib ◽  
Aulia Isramaulana
Keyword(s):  
Global Warming ◽  
Water Level ◽  
Neap Tide ◽  
Spring Tide ◽  
Extreme Conditions ◽  
The Sun ◽  
The Moon ◽  
Gravitational Forces ◽  
The Earth ◽  
The Dead

Regional development engineering in coastal areas, tidal land reclamation, delta area reclamation and port planning, tidal knowledge is very important. Tides mainly occur due to the gravitational forces of the moon, sun, and other planets. The influence of different gravitational forces can be predicted precisely because the rotation and revolutionary movements of the earth, moon, sun, and other planets take place with very high order. The tidal period every day is mainly determined by the rotation of the earth with a 24-hour period. Influence of the sun even though its attraction is only half that of the lunar pull, its influence should not be ignored As understood months around the earth with a period of about 29.5 days. When the position of the moon-earth-sun is in line, the tidal forces of the sun and moon strengthen each other. At that time spring tide occurred. Whereas if the sun-earth forms an angle of 90 degrees, then the minimum tides occur (neap tide). The two conditions are about 7 days old, according to the moon's revolution. Because of the influence of the inertia of the mass of water, the spring and neap tide occur between one and three days after these extreme conditions occur. In short-term studies often researchers take extreme conditions, namely during the tidal peak and peak tide (spring tide), because it does not require a long time compared to researching during a longer tide period. The research approach that will be carried out is whether the tide and peak peaks still occur 1-3 days after the full moon and the dead moon, whether there is a change in the height of the tide and ebb during a certain period due to global warming. As a result of global warming, it is also an effect on the water level of the Barito River. There was a decrease in the maximum water level which previously was around 3 m, now only around 2 m, the minimum water level previously around 2 m was now below 1 m. This will affect the hydrotopographic conditions of tidal swamp land, land that was previously type A can change to type B and so on. The highest tides on the Barito River often occur in the dead months, namely the 1st and 29th of the Hijri.

Tidal studies on Aldabra

1971 ◽  
Vol 260 (836) ◽  
pp. 93-121 ◽  
Keyword(s):  
Water Level ◽  
Time Lag ◽  
Spring Tide ◽  
High Water ◽  
Wire Mesh ◽  
Tidal Range ◽  
Masking Effect ◽  
Phase Lag ◽  
Central Pacific ◽  
Du Bois

The oceanic tide at Aldabra possesses a very large range for an atoll owing to the influence of the Mozambique Channel. The mean spring-tide range, expressed as 2 ( M 2 + S 2 ), is 2.74 m. This is much greater than the 0.5 m common to the majority of central Pacific atolls, and the 0.7 to 1.7 m for Indian Ocean atolls. Ten tide-recording stations were set up by members of the expedition. Foxboro—Yoxall tide-gauge records were obtained from most sites, though there are few accessible rock ledges near deep water suitable for the instrument, especially in the lagoon. Visual records were used extensively in a detailed study of the tidal system in Passe Houareau. Tidal predictions for Aldabra found in Admiralty Tide Tables possess marked lagoonal characteristics. They originate from ‘Grand Poste’, a site well within Grande Passe. It is recommended that records for Passe du Bois be taken as standard since they most closely represent the oceanic tide. Empirically derived tide-predicting graphs are presented for key stations around the atoll, using Kilindini as standard port. Reduction in tidal range is pronounced in the lagoon and is conspicuous even near the mouths of the major channels. Within Passe Houareau spring-tide amplitudes may be a mere 1.2 m only 500 m from the channel mouth where the oceanic range is 3.3 m. Time lag increases lagoonwards more rapidly at Passe Houareau than at either Passe du Bois or Grande Passe, and is greater at low water than at high because of the very shallow nature of the lagoon floor. The greatest recorded phase lag occurs at the head of Bras Cinq Cases, where high water is delayed by 4 1/4 h at major spring tides: at neaps the whole region is dry at high water. Harmonic analyses are presented for one oceanic and two lagoonal stations. Computer synthesis of neap tides in the lagoon demonstrates a monthly masking effect produced by prominent shallow water harmonics. This results in the lagoon being virtually tideless on the smallest neap tides. Strong higher harmonics are indicated by visual records for Ilot Marquoix at the eastern end of the lagoon. These are characterized by a plateau-like high water, where the level commonly remains stationary for over 3 h. Lagoon tide curves are markedly asymmetrical, and often show linear ebb profiles, indicating that the lagoon behaves as a simple water-filled basin in many areas. Drainage off lagoon platforms is slow, water level falling by only 3 to 5 cm h -1 . This results in the tide ebbing for to 10 h out of the 12 1/2 h cycle. Towards spring tides more water enters the lagoon through Passe Houareau than can drain away before the next tide. Water level gradually builds up until at major springs a foot of water covers the lagoon platform at low tide. Extreme low water coincides with neap tides. Because of this ponding effect significant differences in insolation are experienced by marine bottom communities. On oceanic platforms extreme low water coincides with spring tides and occurs at midday: in the lagoon, platforms are most exposed between 06h00 and 08h00 and are always covered at noon. The effects of solar insolation are therefore minimal throughout much of the Aldabra lagoon, but are at a maximum around the coast. Tidal currents were measured in each of the Passes. In the western channels maximum values of 1.5 m s -1 (3 knots) were recorded in Passe du Bois. In Passe Gionnet a peak ebb value of 3.7 m s -1 (7.2 knots) was attained at high springs, with 3 m s -1 (6 knots) sustained for over 2 h. Flow/ebb current reversals are rapid, and in Passe Gionnet accompanied by the development of standing waves. Many channels are floored with trains of reversing sand megaripples. Elsewhere scour is appreciable; a wire mesh shark cage on the floor of Passe du Bois being undercut by 25 cm in 2 weeks. Transitory megarippled sandbanks occur on the eastern flank of Passe Houareau, and bottom facies throughout the lagoon are sculptured by the strong tidal scour.

Experiment Study on Force of Hoisting Triangular Gate of Ship Lock in Tidal Reach

2013 ◽  
Vol 391 ◽  
pp. 402-405
Author(s):  
Teng Wu ◽  
Jian Ding ◽  
Ling Li Wu
Keyword(s):  
Water Level ◽  
Spring Tide ◽  
High Water ◽  
Tidal Range ◽  
Water Control ◽  
Absolute Value ◽  
Tidal Reach ◽  
Lock In ◽  
Lock Gate ◽  
Ship Lock

A physical model of Jiaogang Ship Lock is established in the paper. Through model test, the force of triangular gate under the condition of opening is studied. The result shows when the upper water level is high water control and when absolute value of upper-lower tidal range is less than 0.5m during the spring tide flux and reflux in the flood season of the Yangtze River in the flood year, the ship lock gate can be opened. When the upper water level is medium water control, the absolute value of upper-lower tidal range to open the ship lock gate should be less than 0.4m. And when the upper water level is low water control, the critical tidal range value is also less than 0.5m.

scholarly journals Analysis of the Water Level Variation in the Polish Part of the Vistula Lagoon (Baltic Sea) and Estimation of Water Inflow and Outflow Transport through the Strait of Baltiysk in the Years 2008–2017

Water ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1328
Author(s):  
Michał Szydłowski ◽  
Wojciech Artichowicz ◽  
Piotr Zima
Keyword(s):  
Statistical Analysis ◽  
Numerical Model ◽  
Baltic Sea ◽  
Water Level ◽  
Vistula Lagoon ◽  
Level Variation ◽  
The Baltic Sea ◽  
Water Level Variation ◽  
The Baltic ◽  
The Vistula Lagoon

The Vistula Lagoon is located in both Poland and Russia along the southern coast of the Baltic Sea. It is connected to the Baltic Sea in the Russian part by the Strait of Baltiysk. The purpose of the paper is to identify the dominant factors underlying the water level variation mechanism at Tolkmicko in the Vistula Lagoon, revealed by a statistical analysis of the measured data and a discussion on the inflow and outflow transport variation through the strait, estimated by numerical modeling. Seawater transport is exceptionally valuable in terms of the hydrological water balance in the lagoon. Historical research on the hydrology of the lagoon shows that the water exchange in the lagoon is quite complex due to the presence of several different sources of water balance, such as seawater inflow, river inflow, groundwater inflow, precipitation, and evaporation. Unfortunately, there are no current data on seawater inflow and outflow through the Strait of Baltiysk due to the lack of continuous flow measurements in the strait. A novelty of the current work is an in-depth statistical analysis of the water level variation in the Polish part of the lagoon over a long time period and an estimation of water transport through the Strait of Baltiysk by use of a numerical model. The model reproduces well the water level variation responding to variations in the sea level outside the lagoon and the wind action over the lagoon. The years 2008–2017 were chosen as the analysis period. A two-dimensional free surface shallow water numerical model of the lagoon was adapted to simulate the water level variation in view of the wind over the lagoon and the sea level variation at one open boundary. Finally, it was concluded that the water level variation on the Polish side of the Vistula Lagoon is dominated by two factors: the water level in the Gulf of Gdańsk and the wind over the lagoon. The average annual marine water inflow into the Vistula Lagoon was estimated to be equal to 15.87 km3.

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