The Experts below are selected from a list of 5001 Experts worldwide ranked by ideXlab platform
Dinesh Chandra Shaha - One of the best experts on this subject based on the ideXlab platform.
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Salt plug formation caused by decreased river discharge in a multi channel estuary
Scientific Reports, 2016Co-Authors: Dinesh Chandra ShahaAbstract:FreshWater input to estuaries may be greatly altered by the river barrages required to meet human needs for drinking Water and irrigation and prevent Salt Water Intrusion. Prior studies have examined the Salt plugs associated with evaporation and Salt outwelling from tidal Salt flats in single-channel estuaries. In this work, we discovered a new type of Salt plug formation in the multi-channel Pasur River Estuary (PRE) caused by decreasing river discharges resulting from an upstream barrage. The formation of a Salt plug in response to changes in river discharge was investigated using a conductivity-temperature-depth (CTD) recorder during spring and neap tides in the dry and wet seasons in 2014. An exportation of saline Water from the Shibsa River Estuary (SRE) to the PRE through the Chunkhuri Channel occurred during the dry season, and a Salt plug was created and persisted from December to June near Chalna in the PRE. A discharge-induced, relatively high Water level in the PRE during the wet season exerted hydrostatic pressure towards the SRE from the PRE and thereby prevented the Intrusion of Salt Water from the SRE to the PRE.
Louis H Motz - One of the best experts on this subject based on the ideXlab platform.
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three dimensional simulation of seaWater Intrusion in coastal aquifers a case study in the goksu deltaic plain
Journal of Hydrology, 2012Co-Authors: Murat Cobaner, Recep Yurtal, Ahmet Dogan, Louis H MotzAbstract:Summary Unplanned exploitation of groundWater from coastal aquifers may cause Salt Water Intrusion in coastal aquifers. Coastal areas are generally overpopulated with fertile agricultural lands and diversified irrigated farming activities. The objective of this study was to develop a model to control/prevent seaWater Intrusion into the coastal aquifer with a case study of the Silifke–Goksu Deltaic Plain. A computer program for the simulation of three-dimensional variable density groundWater flow, SEAWAT, is used to model the seaWater Intrusion mechanism of the Goksu Deltaic Plain along the Mediterranean coast of Turkey. The calibration analysis of the developed seaWater Intrusion model is performed using field measured data in the Water-year of 2008 including static groundWater head, electrical conductivity, total dissolved solid (TDS), and chloride concentration values collected from 23 observation wells and the existing data which were compiled and reviewed. The main objectives for applying the seaWater Intrusion model to the Goksu Deltaic Plain were (1) to determine the hydraulic and hydrogeologic parameters of the aquifer, (2) to estimate the spatial variation of the Salt concentration in the aquifer and (3) to investigate the impact of the increase and decrease in groundWater extractions. The simulation results show that the Goksu Deltaic Plain aquifer is especially sensitive to the increase in groundWater extraction.
H H G Savenije - One of the best experts on this subject based on the ideXlab platform.
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saline Water Intrusion in relation to strong winds during winter cold outbreaks north branch of the yangtze estuary
Journal of Hydrology, 2019Co-Authors: Erfeng Zhang, H H G Savenije, Shu Gao, Shuai CaoAbstract:Abstract The strong saline Water Intrusion in the North Branch of the Yangtze Estuary threatens the freshWater supply of the region in winter half year. Strong northerly winds have been identified as a factor increasing saline Water Intrusion. However, there are few studies on this subject, and the mechanisms of winds influencing saline Water Intrusion are still unclear. In the present contribution, we investigate the variation trend of strong wind events during cold outbreaks in winter half year and their correlation with saline Water Intrusion in the North Branch, together with the processes and mechanism of strong winds increasing saline Water Intrusion, based on observations and an analytical Salt Water Intrusion model. The results indicate that the strong northerly and northeasterly wind events and saline Water Intrusion in the North Branch have similar variation trends in 1994–2008, both being relatively weak in the 1990s but being intensified dramatically after 1999. The significant correlation between these two trends suggests that the increase in strong wind events may be one of the factors inducing the enhanced saline Water Intrusion. Observations and model output show that the strong northerly and northeasterly winds can induce dramatic Water level setup, increase of flood-tide current velocities, decrease of ebb-tide velocities, and decrease of freshWater inflow into the North Branch. These changes in combination cause the enhanced intensity of saline Water Intrusion. The Ekman transport from remote winds results in Water level setup at the estuary mouth pumping more seaWater into the North Branch, which should be a dominant mechanism inducing the change in hydrodynamics and increase of saline Water Intrusion.
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Salt Intrusion in the pungue estuary mozambique effect of sand banks as a natural temporary Salt Intrusion barrier
Hydrology and Earth System Sciences Discussions, 2008Co-Authors: S Graas, H H G SavenijeAbstract:Abstract. This paper presents a Salt Intrusion model for the Pungue estuary with the aim to determine the minimum discharge required to prevent the Salt Intrusion from reaching the Water intake situated 82 km from the estuary mouth. The Pungue river is shared between Zimbabwe and Mozambique and has a large variation in precipitation and runoff. The mean monthly discharge can be as low as 8 m3/s and as high as 893 m3/s. The second largest city of Mozambique, Beira, relies on the Pungue for its Water supply. In the dry season it frequently occurs that the Water intake has to be ceased because the salinity of the Pungue is too high. The Salt Intrusion model used in this paper is based on a fully analytical and predictive theory which is confronted with measurements of Salt Intrusion and estuary topography. The paper presents the collection of estuary characteristics and the Salt Water Intrusion measurements that were obtained by field measurements in 1993 and 2002. Using these data the Salt Intrusion model has successfully been applied. During salinity Intrusion measurements in the dry season of 1993 it was observed that sand banks in the middle zone of the estuary prevented the Salt Water from intruding further upstream, resulting in lower salinity levels upstream than the theoretical Salt Water Intrusion model predicts. This effect occurs during ebb of neap and average tides and can reduce the Salt Water Intrusion by 10 km. The model indicates that in a natural situation a minimum monthly discharge of 12 m3/s is required to maintain acceptable salinity levels during high Water and spring tide near the Water intake. The actual Water discharge upstream of the Water intake has to be higher, since this minimum discharge does not take into account the Water abstracted for irrigation and/or urban Water supply. Current Water abstractions lead to Salt Water Intrusion near the Water intake at approximately 10% of the time. The model indicates that an additional Water abstraction of 5 m3/s will lead to an increase in Salt Water reaching the intake at 10% of the time. During neap tide the sand banks act as a temporary natural Salt Intrusion barrier reducing the chance of Salt Water reaching the Water intake.
Yiquan Qi - One of the best experts on this subject based on the ideXlab platform.
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tides and tidal currents in the pearl river estuary
Continental Shelf Research, 2004Co-Authors: Yiquan QiAbstract:Several cruises were conducted to investigate the variability in tidal levels, tidal flows, and Water circulation in the Pearl River estuary during the dry and wet seasons in 1998. Unlike other temperate estuaries, the average tidal range was small in the offshore Waters and increased gradually towards the estuary, reaching the maximum in the upstream part of the Pearl River estuary. The extent of the amplitude increment was different between the diurnal and semi-diurnal constituents. The percentage of sea level variance in the semi-diurnal band increased when the tide progressed upstream, but it reversed in the diurnal band. Thus, the accentuated sea level variance in the semi-diurnal band resulted in the increased amplitudes of semi-diurnal constituents which were larger than diurnal constituents. The distribution of the mean current in the estuary depicted an anti-clockwise circulation in the estuary: freshWater was dominant on the western side of the estuary, while Salt Water was dominant on the eastern side. The Pearl River estuary also showed a typical Salt wedge circulation: a Salt Water Intrusion largely occurred via the eastern channel in the estuary while river outflow dominated the western channel. In this study, long time series and large spatial coverage of tide and current observations allow in depth analysis of the temporal and spatial variations of tide and circulation, and the associated influence from open ocean in the Pearl River estuary.
T P Clement - One of the best experts on this subject based on the ideXlab platform.
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theoretical analysis of the worthiness of henry and elder problems as benchmarks of density dependent groundWater flow models
Advances in Water Resources, 2003Co-Authors: Matthew J Simpson, T P ClementAbstract:Computer models must be tested to ensure that the mathematical statements and solution schemes accurately represent the physical processes of interest. Because the availability of benchmark problems for testing density-dependent groundWater models is limited, one should be careful in using these problems appropriately. Details of a Galerkin finite-element model for the simulation of density-dependent, variably saturated flow processes are presented here. The model is tested using the Henry Salt-Water Intrusion problem and Elder Salt convection problem. The quality of these benchmark problems is then evaluated by solving the problems in the standard density-coupled mode and in a new density-uncoupled mode. The differences between the solutions indicate that the Henry Salt-Water Intrusion problem has limited usefulness in benchmarking density-dependent flow models because the internal flow dynamics are largely determined by the boundary forcing. Alternatively, the Elder Salt-convection problem is more suited to the model testing process because the flow patterns are completely determined by the internal balance of pressure and gravity forces.
