Effect of Tidal Range, Temperature and Fresh Water on the Amount of Silt in Suspension in an Estuary

Nature ◽  
1964 ◽  
Vol 201 (4923) ◽  
pp. 1017-1017 ◽  
Author(s):  
W. H. JACKSON
Keyword(s):  
Water ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 584
Author(s):  
Weiyi Xia ◽  
Xiaodong Zhao ◽  
Riming Zhao ◽  
Xinzhou Zhang

The salt-fresh water mixing is one of the basic topics of estuarine dynamics research. In partially mixed and highly stratified mixed estuaries, the structure of stratified flow is complicated by density gradient and tidal reciprocating flow. The velocity and salinity structures have been experimentally studied in a flume which is 167.8m long, 0.5m wide, and 0.5m deep. The processes of the tidal levels, the flood and ebb current, and the salt-fresh water mixing have been simulated. Furthermore, the partially mixed and highly stratified mixed types have been repeatability showed in the flume, by solving the problems of experiment control and saltwater recycling. The control variable method has been used to dialectically analyze the influence of tidal range and runoff volume on the velocity and salinity distribution. The tide and runoff are respectively considered to affect the mixing type in two contradictory ways. In the condition of tidal reciprocating flow, the periodical change of interface stability has been investigated. It is considered that the interface stability is closely related to the vertical gradient of density and velocity. As a result, the critical value of interface stabilization has been presented. The experimental data and research results can be used for the basic study of estuarine dynamics and applied to practical problems such as estuarine saltwater intrusion.


Author(s):  
Mingyuan Yang ◽  
Wei Zhang

Ling Ding Yang (LDY) estuary is one of the main parts of the whole Zhujiang estuary, which lies in the south sea, China. It is about 60km wide from Hong Kong in the east to Macao in the west and the water areas are approximately 2110 km2. The mixing process of salt water and fresh water in the estuary is influenced by many factors, such as the estuarine geometry, tidal range and ravine flows, etc. In this paper, based on the data from the tidal gauge stations and synchronously surveyed data during July 2003, a study on the temporal and spatial distribution characteristics of salinity was made. According to the observation data, in wet season, the fresh water and salt water mixes with the N parameter between 0.21 and 1.63. The distribution of salinity concentration in the east part of LDY is due to coriolis’ force. The salinity concentration decreases from the sea to the estuary, and there exists apparent division point, Nei Lingding Island. To the south of Nei Lingding Island, it is almost partially mixed, and to the north of Nei Lingding Island, it belongs to highly stratification. At the same time, the stratification parameter and the vertical mean velocity in wet season are compared. The N parameter changes with the velocity of tide flow in a tidal cycle. The value of N in a flood tide is usually larger than that is in an ebb tide. That is to say, the mix intensity is much bigger in the flood tide.


2021 ◽  
Author(s):  
Constantinos Matsoukis ◽  
Laurent O. Amoudry ◽  
Lucy Bricheno ◽  
Nicoletta Leonardi

<p>High salinity values in deltaic regions can be detrimental for agriculture, aquaculture and human consumption. Salinity levels in river deltas could significantly increase due to sea level rise and infrastructure works such as river diversions or dam constructions. River flow and tides have a large influence on salinity concentrations and it is thus important to understand their combined role. In this paper, a 3D model is built for an idealized delta. A series of simulations is carried out to investigate salinity fields developed under the combined action of tidal amplitude and fresh water flow. Simulations are classified based on the ratio between fresh water and tidal range. Both tide influenced and river dominated cases were considered. Results emphasize the importance of tidally driven mixing which can establish fresher conditions in the delta for certain amplitudes. Tidal amplitude increase enhances the flow in the delta and enlarges the fresh water layer thickness and length. On the other hand, the maximum tidal ranges can limit significantly the fresh water volume. The spatiotemporal salinity distribution is described in terms of delta topology and network geometry. Salinity and river discharge were found to be negatively and exponentially correlated by an equation that resembles solutions of the 1D advection-diffusion equation. Large bathymetric differences between delta areas were identified to play a key role on the salinity patterns as they can modify the nature of the extracted relationships and correlations.</p>


2017 ◽  
Vol 12 (2) ◽  
pp. 105-116
Author(s):  
Pulung A. Pranantya ◽  
Nurlia Sadikin

In terms of geology, most areas in south of the Gunungkidul District in Central Java consist of the Wonosari formation limestone. The land is generally very dry and source of raw water is also difficult to reach. Findings on the existence of underground river in caves, however, indicate the potential amount of water within the area, especially in the eastern part of the Gunungkidul District. Although limited information available, some fishermen have discovered that Seropan cave contains fresh water source. This cave is situated at 65 m below the cliff. Initial exploration, which done using a multichannel resistivity method, confirmed the availability of freshwater in the cave and underground river. The isopach of cave depth is found in ranges of 80 200 m below the ground surface. The water of Seropan cave can be utilized by implementing pipeline or by drilling at the suggested point based on the interpretation results, i.e. 110o2223.6388 EL 8o42.874 SL. [DY1][PP2][DY1]Perbaiki grammarIn terms of geology, most areas in south of Gunungkidul District in Central Java consist of the Wonosari formation limestone. The land is generally very dry and source of raw water is also difficult to reach. Findings on the exixtence of underground river in caves, however, indicate potential amount of water within the area especially in eastern part of Gunungkidul District. Although limited information available, some fishermans has discovered that Seropan cave contain fresh water source. This cave is situated at 65 m below the cliff. Initial exploration, which done using multichannel resistivity method, confirmed the availability of freshwater in the cave and underground river. The iso pach of cave depth is found in ranges of 80 200 m below the ground surface. The water of Seropan cave can be utilized by implementing pipeline or by drilling at the suggested point based on the interpretation results i.e. 110o2223.6388 EL 8o42.874 SL.[PP2]Sudah diperbaiki


2017 ◽  
Vol 23 (1) ◽  
Author(s):  
V.K. YADAV ◽  
SONAM SHARMA ◽  
A.K. SRIVASTAVA ◽  
P.K. KHARE

Ponds are an important fresh water critical ecosystem for plants and animals providing goods and services including food, fodder, fish, irrigation, hydrological cycle, shelter, medicine, culture, aesthetic and recreation. Ponds cover less than 2 percent of worlds land surface. Ponds are important source of fresh water for human use. These are threatened by urbanization, industrialization, over exploitation, fragmentation, habitat destruction, pollution, illegal capturing of land and climate changes. These above factors have been destroying ponds very rapidly putting them in danger of extinction of a great number of local biodiversity. It is necessary to formulate a correct conservation strategy for pond restoration in order to meet the growing needs of fresh water by increasing the human population. Some measures have been compiled and proposed in the present review.


2017 ◽  
Vol 23 (2) ◽  
Author(s):  
SUNITA BORDE ◽  
ASAWARI FARTADE ◽  
AMOL THOSAR ◽  
RAHUL KHAWAL

Ptychobothridean genera like Senga and Circumoncobothrium are the common parasites of fresh water fishes. The genotypic study of these parasites was taken by RAPD. The RAPD profile of these two parasites were not similar to each other as depicted by the band pattern in picture. These results suggest the presence of inter-specific polymorphism among cestode parasites of two different genera for RAPD analysis. The present study demonstrated that genetic differentiation of cestode parasites could be accomplished on the basis of genomic variation with polymorphic band pattern using RAPD. All the detected bands (PCR product) were polymorphic and band size ranged from 500-5000 bp in length. The RAPD of profiles using GBO-31, GBO-32, GBO-33, GBO-34, GBO-35 and GBO-36. Primers were able to characterize inter-specific polymorphism among the two genus ( Senga and Circumoncobothrium ). Genetic analysis suggests that Senga and Circumoncobothrium show genetic diversity with respect to RAPD patterns using all the six primers used for the present study. The genetic distance between the analyzed genuses ranged from 0.14 to 0.80. The differentiation of the two parasites on the basis of genetic markers could greatly facilitate study on the biology of these parasites.


2018 ◽  
Vol 24 (2) ◽  
Author(s):  
R.R. DANDAWATE

Present paper deals with study of cestode parasites of genus Circumoncobothrium from fresh water fish Clarius batracus at Savitri river, (Dapoli) for the percentages of infection occurance during summer season,minimum during winter and tolarate during rainy season.The parasite mainly infected the intestine of host and fed on nutrients from digested food. It completed its life cycle in the intestine of host. By camparing different characters of it to identify that the species is new


2019 ◽  
Vol 25 (1) ◽  
Author(s):  
ADITYA NARAYAN

The present investigation deals with the prevalence of infection of cestode, Pseudoinverta oraiensis19 parasitizing Clarias batrachus from Bundelkhand Region (U.P.) India. The studies were recorded from different sampling stations of Bundelkhand region of Uttar Pradesh. For this study 360 fresh water fish, Clarias batrachus were examined. The incidence of infection, monsoon season (17.50%) followed by winter season (20.00%) whereas high in summer season (30.00%).


1983 ◽  
Vol 21 (2) ◽  
pp. 187 ◽  
Author(s):  
Jae Ku Rhee ◽  
Ho Il Lee ◽  
Byeong Kirl Baek ◽  
Pyung Gil Kim
Keyword(s):  

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