scholarly journals Vulnerability of the Indus River Delta of the North Arabian Sea, Pakistan

2016 ◽  
Vol 18 (3) ◽  
pp. 599-610 ◽  
Keyword(s):  
Seawater Intrusion ◽  
Social Impact ◽  
Sea Water ◽  
River Estuary ◽  
Weather Conditions ◽  
Ocean Model ◽  
Indus River ◽  
The North ◽  
Meteorological Observations ◽  
Coastal Ocean Model

<div> <p>Seawater intrusion has been a serious problem in the Indus River Estuary (IRE) for decades. The literature reviews, hydrological and meteorological observations were analyzed to examine and discuss the causes and consequences of seawater intrusion in the IRE. Both sea water intrusion and coastal erosion are having a devastating environmental and social impact and the whole ecosystem of the Indus Delta is facing serious threat. The Indus deltaic region is not only threatened by continuing activities upstream but also by the neighboring sea in the south, due to the impacts of local weather conditions. Observational results suggest that seawater intrusion reaches 84 km upstream in the IRE during the dry season. Extensive field investigations and a high resolution coastal ocean model are urgently needed for future study.</p> </div> <p>&nbsp;</p>

scholarly journals Numerical Study on the Expansion and Variation of Changjiang Diluted Water in Summer and Autumn

2021 ◽  
Vol 9 (3) ◽  
pp. 317
Author(s):  
Wanli Hou ◽  
Menglin Ba ◽  
Jie Bai ◽  
Jianghua Yu
Keyword(s):  
Yangtze River ◽  
Sea Water ◽  
Numerical Study ◽  
River Estuary ◽  
Ocean Model ◽  
Theoretical Research ◽  
Yangtze River Estuary ◽  
Hydrodynamic Characteristics ◽  
Changjiang Diluted Water ◽  
Transportation Route

In view of the expansion and directional change mechanisms of Yangtze River water diluted with sea water in the shelf region (also known as Changjiang diluted water [CDW]) during summer and autumn, a three-dimensional hydrodynamic model of the Yangtze River Estuary (YRE) and its adjacent waters was established based on the Finite Volume Community Ocean Model (FVCOM). Compared with the measured data, the model accurately simulates the hydrodynamic characteristics of the YRE. On that basis, the influence of the expansion patterns of the CDW in both summer and autumn was studied. It was found that, in 2019, the CDW expanded to the northeast in the summer and to the southeast in the autumn, and that the route of the CDW is mainly controlled by the wind, not the runoff. Current seasonal winds also change the transportation route of the CDW by affecting its hydrodynamic field. Typhoons are frequent in both summer and autumn, causing abnormalities in both the transportation route and expansion of the CDW. During a typhoon, a large amount of the CDW is transported in a continuous and abnormal manner, accelerating the path turning of the CDW. This paper enhances the existing theoretical research of the CDW and provides a reference with respect to the expansion of diluted water all over the world.

Numerical Simulation of the Residual Current during the Dry Season in the Lingdingyang Bay, China

2014 ◽  
Vol 955-959 ◽  
pp. 2996-3000
Author(s):  
Biao Wang ◽  
Jian Rong Zhu
Keyword(s):  
Spring Tide ◽  
River Estuary ◽  
Circulation Pattern ◽  
Pearl River Estuary ◽  
Ocean Model ◽  
Dry Season ◽  
Residual Current ◽  
Lateral Circulation ◽  
Coastal Ocean Model ◽  
The Pearl River

The hydrodynamics in the Lingdingyang Bay of the Pearl River Estuary is complicated due to the combined effect of river runoff, tide and bathymetry. In this paper, the residual current patterns were investigated in the Lingdingyang Bay during the dry season based on Finite-Volume Coastal Ocean Model (FVCOM). The horizontal distributions of the residual current suggest that during both neap and spring tide the residual current is relatively strong at the surface while it weakens quite a lot at the bottom. Due to the northeasterly wind, a lateral circulation westward at the surface and eastward at the bottom is also found, which is more evident during neap tide than spring tide. The vertical profiles of residual current along deep channels show an obvious spring-neap variation, with the strongest estuarine circulation pattern during the moderate tide after neap.

Origin and modelling of water salinization in a coastal aquifer of the Bay of Bengal: The Kaluvelly watershed, Tamil Nadu, India

2006 ◽  
Vol 177 (6) ◽  
pp. 333-345 ◽  
Author(s):  
Noémi D’ozouville ◽  
Sophie Violette ◽  
Nathalie Gassama ◽  
Aline Dia ◽  
Nathalie Jendrzejewski
Keyword(s):  
Fresh Water ◽  
Seawater Intrusion ◽  
Tamil Nadu ◽  
Sea Water ◽  
Water Movement ◽  
Unknown Parameters ◽  
Subsequent Increase ◽  
Geological Investigation ◽  
Rock Interaction ◽  
The North

Abstract Over-pumping of the Vanur sandstone aquifer has led to a lowering of the piezometric surface and degradation of water quality through increased salinization. This aquifer salinization is a good example of many similar problems in India and other parts of the world. The Vanur Formation is the main aquifer of a multilayered system bordered by the sea on the eastern side and partly overlaid by the brackish waters of the Kaluvelly swamp in the north. The origin of the salinity, which apparently is not simply seawater intrusion, and its dynamics are examined, using chemical and isotopic tools together with 1D hydrological modelling of the movement of the seawater/fresh water interface. The content of major elements and some trace elements as well as isotopic ratios (18O/16O, D/H and 87Sr/86Sr) were measured in groundwater, surface and rainwater during five sampling surveys (January 1999 to October 2001). Available data on rainfall, piezometric and hydrogeologic records were used. We identified human contamination by F, Li in parts of the aquifer, which invalidated their use as tracers. The chemical composition of water from the Vanur aquifer shows a classical chemical evolution from the recharge area to the deeper confined area, consisting in increased water-rock interaction and a subsequent increase of solute species. However, the range of major compound concentration ratios for some wells does not follow this general trend. The non-consistent points are located in the most depressed area of the aquifer (−20 m amsl in June 2000), except in the north where the brackish water of the Kaluvelly swamps seems to enter the aquifer. In the depressed area, the sulphate signature corresponds to a mixing with a mineralized and sulphate-rich water body, likely to be Ramanathapuram sandstone water. It is due to the upward leakage from this underlying formation. A seasonal evaporation signature recorded by stable isotopes (δ18O, δD) suggests the addition of return irrigation flow. The 1D hydrodynamical model of the sea-water/fresh water movement was built with the available geological and hydraulic data. Hydrodynamic calculations show that seawater intrusion can be expected to occur within 3 to 20 years after the year 2000, depending on the value of unknown parameters (porosity) or boundary conditions (recharge, pumped volume). But we cannot rule out that a lithologic or tectonic barrier prevent any seawater intrusion inland; future geological investigation has to be done to confirm or infirm this hypothesis.

Water exchange and renewal times of a micro-tidal fjord in isohaline coordinates

2021 ◽  
Author(s):  
Xaver Lange ◽  
Markus Jochum
Keyword(s):  
Water Exchange ◽  
Layer Structure ◽  
High Sensitivity ◽  
Ocean Model ◽  
Grid Turbulence ◽  
Exchange Flow ◽  
Transitional Area ◽  
The North ◽  
Coastal Ocean Model ◽  
Horizontal Density Gradient

&lt;p&gt;In micro-tidal coastal systems, the hydrodynamics in fjords reduce to a competition between horizontal density gradient, friction and wind stress. Depending on the depth of the entrance sill, the importance of these factors for water exchange varies within the vertical layer structure of fjords. This study investigates these renewals of water bodies in an isohaline framework, using the example of the Gullmar Fjord on the west coast of Sweden, a transitional area between the brackish Baltic Sea and the northeastern region of the North Sea.&lt;/p&gt;&lt;p&gt;To estimate the influence of wind and baroclinic pumping on volume and salinity transport and their importance on the exchange time scales, a well-validated, realistic, and highly resolved 3D coastal ocean model (GETM) is used, calibrated with especially designed observations. Simulations were combined with passive numerical tracers and evaluated with the mathematical analysis framework of the Total Exhange Flow (TEF).&lt;/p&gt;&lt;p&gt;The results highlight the advantage of isohaline coordinates in the study of water mass transformations within the fjord, compared to geographic coordinates, and the high sensitivity of the exchange flow to sub-grid turbulence.&lt;/p&gt;

Numerical modelling study of seawater intrusion in Indus River Estuary, Pakistan

2019 ◽  
Vol 184 ◽  
pp. 74-84 ◽  
Author(s):  
Jun Wang ◽  
Li Li ◽  
Zhiguo He ◽  
Noor Ahmed Kalhoro ◽  
Dongfeng Xu
Keyword(s):  
Numerical Modelling ◽  
Seawater Intrusion ◽  
River Estuary ◽  
Indus River ◽  
Modelling Study

scholarly journals IODP expedition 347: Baltic Sea basin paleoenvironment and biosphere

2015 ◽  
Vol 20 ◽  
pp. 1-12 ◽  
Author(s):  
T. Andrén ◽  
B. Barker Jørgensen ◽  
C. Cotterill ◽  
S. Green ◽  
Keyword(s):  
High Resolution ◽  
Baltic Sea ◽  
Sea Water ◽  
River Estuary ◽  
Laminated Sediments ◽  
The Baltic Sea ◽  
Deep Basin ◽  
Scientific Drilling ◽  
The North ◽  
The Baltic

Abstract. The Integrated Ocean Drilling Program (IODP) expedition 347 cored sediments from different settings of the Baltic Sea covering the last glacial–interglacial cycle. The main aim was to study the geological development of the Baltic Sea in relation to the extreme climate variability of the region with changing ice cover and major shifts in temperature, salinity, and biological communities. Using the Greatship Manisha as a European Consortium for Ocean Research Drilling (ECORD) mission-specific platform, we recovered 1.6 km of core from nine sites of which four were additionally cored for microbiology. The sites covered the gateway to the North Sea and Atlantic Ocean, several sub-basins in the southern Baltic Sea, a deep basin in the central Baltic Sea, and a river estuary in the north. The waxing and waning of the Scandinavian ice sheet has profoundly affected the Baltic Sea sediments. During the Weichselian, progressing glaciers reshaped the submarine landscape and displaced sedimentary deposits from earlier Quaternary time. As the glaciers retreated they left a complex pattern of till, sand, and lacustrine clay, which in the basins has since been covered by a thick deposit of Holocene, organic-rich clay. Due to the stratified water column of the brackish Baltic Sea and the recurrent and widespread anoxia, the deeper basins harbor laminated sediments that provide a unique opportunity for high-resolution chronological studies. The Baltic Sea is a eutrophic intra-continental sea that is strongly impacted by terrestrial runoff and nutrient fluxes. The Holocene deposits are recorded today to be up to 50 m deep and geochemically affected by diagenetic alterations driven by organic matter degradation. Many of the cored sequences were highly supersaturated with respect to methane, which caused strong degassing upon core recovery. The depth distributions of conservative sea water ions still reflected the transition at the end of the last glaciation from fresh-water clays to Holocene brackish mud. High-resolution sampling and analyses of interstitial water chemistry revealed the intensive mineralization and zonation of the predominant biogeochemical processes. Quantification of microbial cells in the sediments yielded some of the highest cell densities yet recorded by scientific drilling.

scholarly journals High resolution simulations on the North Aegean Sea seasonal circulation

2003 ◽  
Vol 21 (1) ◽  
pp. 251-265 ◽  
Author(s):  
V. H. Kourafalou ◽  
K. Barbopoulos
Keyword(s):  
High Resolution ◽  
Sea Water ◽  
Eastern Mediterranean ◽  
Aegean Sea ◽  
Ocean Model ◽  
The Black Sea ◽  
The North ◽  
Seasonal Characteristics ◽  
North Aegean ◽  
North Aegean Sea

Abstract. The seasonal characteristics of the circulation in the North Aegean Sea are examined with the aid of a climatological type simulation (three-year run with perpetual year forcing) on a fine resolution grid (2.5 km by 2.5 km). The model is based on the Princeton Ocean Model with a parameterisation of plume dynamics that is employed for the input of waters with hydrographic properties that are different than the properties of basin waters, as the Black Sea Water (BSW) outflow through the Dardanelles Strait and riverine sources. The model is nested with a sequence of coarser regional and basin-wide models that provide for the long-term interaction between the study area and the Eastern Mediterranean at large. The results are employed to discuss the response of the North Aegean to the important circulation forcing mechanisms in the region, namely wind stress, heat and salt fluxes, buoyancy due to rivers and the BSW outflow (which is low in salinity and occasionally low in temperature) and the interaction with the Southern Aegean. The high resolution allows for the detailed representation of the complicated topography that presides in the region. This helps produce a rich eddy field and it allows for variability in the pathways of BSW that has implications in the basin hydrography and circulation.Key words. Oceanography: general (continental shelf processes; numerical modeling)

scholarly journals Mapping of Seawater Intrusion into Coastal Aquifer: A Case Study of Pekalongan Coastal Area in Central Java

2020 ◽  
Vol 6 (1) ◽  
pp. 183
Author(s):  
Muhammad Irham Sahana ◽  
Roh Santoso Budi Waspodo
Keyword(s):  
Groundwater Quality ◽  
Seawater Intrusion ◽  
Ad Hoc ◽  
Sea Water ◽  
Chloride Ion ◽  
Distance Method ◽  
The North ◽  
Central Java ◽  
Freshwater Zone ◽  
Logarithmic Equation

Seawater intrusion promotes the degradation of groundwater quality through excessive pumping activities or natural phenomena such as tidal floods which are popular with coastal areas. Pekalongan city is one of the areas affected by this phenomenon and was analyzed in this study with reference to the 1986 Ad Hoc Sea Water Intrusion (PAHIAA) Decree which classifies water into five based on salinity. This involved using the Integrated Distance Method (IDW) to map and applying the logarithmic equation to determine the dispersion relationship. The results showed seawater intrusion has already affected groundwater quality up to 6.52 km from the coastline for total dissolved solids and electrical conductivity and 7.22 km for chloride ion.  The distribution of TDS, EC, and Cl- in the freshwater zone was also recorded to have reached 28.59 km2, 28.36 km2, and 23.95 km2 respectively. It is predicted that in 4 years, there would no longer be freshwater in Padukuhan Kraton Village due to decreasing groundwater quality caused by seawater intrusion. Furthermore, 23.03 km2 Pekalongan area which spread into 4.34 km2 to the West, 0 km2 to the South, 14.39 km2 to the North, and 1.28 km2 to the East of the district has also been affected and was discovered to be caused mainly by tidal flood from Bremi and Tirto rivers. 

Investigational Studies on Quantity of Salinity in Netravati River Estuary Sand-Coastal Karnataka

2018 ◽  
Vol 6 (6) ◽  
pp. 46
Author(s):  
Raveesha P ◽  
K. E. Prakash ◽  
B. T. Suresh Babu
Keyword(s):  
Brackish Water ◽  
Sea Water ◽  
Salt Water ◽  
Construction Material ◽  
Salt Content ◽  
River Estuary ◽  
Sand Sample ◽  
River Sand ◽  
Natural Aggregates

The salt water mixes with fresh water and forms brackish water. The brackish water contains some quantity of salt, but not equal to sea water. Salinity determines the geographic distribution of the number of marshes found in estuary. Hence salinity is a very important environmental factor in estuary system. Sand is one major natural aggregate, required in construction industry mainly for the manufacture of concrete. The availability of good river sand is reduced due to salinity. The quality of sand available from estuarine regions is adversely affected due to this reason. It is the responsibility of engineers to check the quality of sand and its strength parameters before using it for any construction purpose. Presence of salt content in natural aggregates or manufactured aggregates is the cause for corrosion in steel. In this study the amount of salinity present in estuary sand was determined. Three different methods were used to determine the salinity in different seasonal variations. The sand sample collected nearer to the sea was found to be high in salinity in all methods.  It can be concluded that care should be taken before we use estuary sand as a construction material due to the presence of salinity.

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