The transport of fresh water from river to coastal zone through a temperate estuary

Uncles, R.J.; Lewis, R.E.

doi:10.1016/s1385-1101(01)00079-x

Cited by 23 publications

(13 citation statements)

References 23 publications

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“…Regulation of the above described fluxes can produce drastic changes in the balance of processes and alter the fluctuations of the physical and chemical characteristics of a coastal lagoon (Comin, 1982). Quantification of water, salt and nutrient exchanges between salt marshes, lagoons, estuaries and the coastal ocean has been conducted in several macro-tidal environments (Uncles and Jordan, 1979;Lewis and Lewis, 1983;Uncles et al, 1986;Dame et al, 1991;Park and James, 1990;Sylaios and Boxall, 1998;Uncles and Lewis, 2001;Mendoza-Salgado et al, 2005). Nevertheless, studies on the factors determining water quality and exchange dynamics with the coastal zone of a typical, Mediterranean, micro-tidal, fishery-exploited coastal lagoon are limited.…”

Section: Introductionmentioning

confidence: 99%

Quantification of Water, Salt and Nutrient Exchange Processes at the Mouth of A mediterranean Coastal Lagoon

Sylaïos

Tsihrintzis

Akratos

et al. 2006

Environ Monit Assess

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Vassova lagoon is a typical Mediterranean (small, shallow, micro-tidal, well-mixed) coastal lagoon, receiving limited seasonal freshwater inflows from direct precipitation and underground seepage. An intensive study was carried out in order to quantify the mechanisms responsible for the intra-tidal and residual transport of water, salt, nutrients and chlorophyll at the mouth of this lagoon and to assess the lagoon's flushing behavior. Results indicated that although the system is micro-tidal, tidal effects appeared to be the dominant factor for the longitudinal distribution of physical and chemical parameters, while the associated residual flow is also important and serves as a baseline measure of overall circulation. However, analysis of the net longitudinal currents and fluxes of water, salt and nutrients revealed the importance of non-tidal effects (wind effect and precipitation incidents) in the mean tidal transport. It is shown that the Eulerian residual currents transported water and its properties inwards under southern winds, while a seaward transport was induced during precipitation incidents and northern winds. The Stokes drift effect was found an order of magnitude lower than the Eulerian current, directed towards the lagoon, proving the partially-progressive nature of the tide. Nutrients and chlorophyll-alpha loads are exported from the lagoon to the open sea during the ebb phase of the autumn and winter tidal cycles, associated with the inflow of nutrient-rich freshwater, seeped through the surrounding drainage canal. The reverse transport occurs in spring and early summer, when nutrients enter the lagoon during the flood tidal phase, from the nutrient-rich upper layer of the stratified adjacent sea. Application of a tidal prism model shows that Vassova lagoon has a mean flushing time of 7.5 days, ranging between 4 to 18 days, affected inversely by the tidal oscillation.

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Section: Introductionmentioning

confidence: 99%

Quantification of Water, Salt and Nutrient Exchange Processes at the Mouth of A mediterranean Coastal Lagoon

Sylaïos

Tsihrintzis

Akratos

et al. 2006

Environ Monit Assess

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“…For example, observations along the Tamar Estuary demonstrated that tidal pumping and vertical shear dominated at spring and neap tides, respectively ( Uncles et al, 1985) . The vertical shear flux at neap tides exceeded that at spring tides in lower reaches of Tamar estuary ( Uncles and Lewis, 2001) . The direction of Stokes' drift flux may be different in spring and neap tides, with upstream in neap tide and downstream in spring tide ( Siegle et al, 2009 ) .…”

Section: Introductionmentioning

confidence: 91%

“…In the case of tidal flow,following the procedure similar to the previous studies ( Ali et al, 2010;Bowden, 1963;Hunkins, 1981;Uncles and Lewis, 2001) , the instantaneous velocity and salinity can be decomposed into term that represent the physical process responsible for the advective and dispersive mass transport. For a lateral homogeneous estuarine channel velocity ( V) and salinity ( S) are decomposed as:…”

Section: Salt Fluxesmentioning

confidence: 99%

“…The tidal effects are component of tidal sloshing, Stokes drift and cross-correlation between tide and salinity ( Kjerfve, 1986;Miranda et al, 2012;Restrepo and Kjerfve, 2002) . In steady-state, there is a balance between seaward advection of fluvial discharge and landward dispersion of saltier ocean water ( Hunkins, 1981;Miranda and Kjerfve, 1998;Siegle et al, 2009;Simpson et al, 1997;Uncles and Lewis, 2001) . The landward salt transport is a consequence of dispersion produced by tidal and wind mixing and by horizontal density gradient ( Vaz, Lencart and Dias, 2012) .…”

Section: Introductionmentioning

confidence: 99%

“…It is the dominant dispersive salt flux during high discharge conditions in Hudson River estuary , an order of magnitude lower than river discharge in Vassova lagoon ( Sylaios et al, 2006) , insignificant in lower reaches of the Tamar estuary ( Uncles et al, 1985) . In most studies, the vertical shear effect contribution was considered negligible ( Ali et al, 2010;Uncles and Lewis, 2001) . But in some lower reaches at neap tides it can be an important flux ( Uncles et al, 1985) .…”

Section: Introductionmentioning

confidence: 99%

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Seasonal Hydrodynamics and Salt Exchange of a Shallow Estuary in Northern China

Zou

Zhang

Meng

et al. 2016

Journal of Coastal Research

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Estuaries are important components of coastal ecosystem and function as dominant pathways of material exchange at the land-sea interface. The transport of terrestrial input through river inflow is controlled by physical process including tides, waves, and fresh water discharge. This study investigates hydrodynamic characteristic and salt flux within Xiaoqinghe River ( XQR) estuary, which is a shallow estuarine system ( water depth < 8 m) and exports substantial amount of nutrients and pollutants to the adjacent Laizhou Bay. Profile velocity and salinity are measured using ADCP and CTD through complete tidal cycles (25 hours) in April, July and September 2013. The instantaneous velocity and salinity data are decomposed into time-averaged means and time-varying components based on the improved Kjerfve (1986) method to quantify the contributions of various physical processes. The results showed that the XQR estuary had irregular semidiurnal tide with tidal form number of 0． 5-0． 7 and tidal range about 2 m. River discharge dominated the seasonal variation of tidal elevation, longitudinal velocity, and salinity. The river mouth was well mixed based on calculated layer Richardson number, and can be classified as Type 1b and 2b according to stratification-circulation diagram. The net salt flux was directed seaward during monsoon season and landward in non-monsoon seasons. Fluvial advective flow dominated the seaward salt flux throughout the year and contributed 78． 9% of the net salt flux in monsoon. Stokes' drift and tidal sloshing dispersion flux dominated the landward salt flux, and contributed 72% and 57． 5% of total salt flux in April and September, respectively. The cross-correlation between tide and salinity, and vertical shear, were only of marginal importance. Overall, tidal sloshing and Stokes' drift is the underlying process of salt transport while river discharge dominates its seasonal variation. This study revealed the inherent unsteadiness of the salt balance, and provided the scientific foundation for effective management of freshwater release from upstream during difference seasons.

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Wind forcing controls on river plume spreading on a tropical continental shelf

2015

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The Berau Continental Shelf is located close to the Equator in the Indonesian Archipelago, hosting a complex of coral reefs along its oceanic edge. The Berau coral reefs have a very high biodiversity, but the area is under serious risk due to river-derived nutrients and sediments. The region is characterized by weak winds, moderate tides, and almost absent Coriolis forcing. Existing knowledge about river plume behavior in tropical environments is limited. The aim of this paper is to investigate the influence of the subtle physical forcing on the dynamics of the Berau river plume. A three-dimensional model (ECOMSED) was calibrated with observational data. The model was forced by freshwater input from the Berau river distributaries, tides at the open boundaries, and measured hourly wind. The model reproduces the freshwater dynamics on the shelf adequately and highlights that the river plume spreads symmetrically for river forcing only. Tides cause vertical mixing and suppress the cross-shelf spreading of the river plume. However, the spreading of the river plume over the shelf is mainly controlled by the weak monsoonal winds, resulting in a seasonal development. During the Southeast Monsoon, the southerly winds push the plume northeastward and cause a stratified water column in the northern part of the continental shelf. Northerly winds during the Northwest Monsoon disperse the plume to the south, promoting a vertically well-mixed water column. The results can be used to predict the possible impact of land-use changes in the steadily developing Berau region on coral reef health.

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The transport of fresh water from river to coastal zone through a temperate estuary

Cited by 23 publications

References 23 publications

Quantification of Water, Salt and Nutrient Exchange Processes at the Mouth of A mediterranean Coastal Lagoon

Quantification of Water, Salt and Nutrient Exchange Processes at the Mouth of A mediterranean Coastal Lagoon

Seasonal Hydrodynamics and Salt Exchange of a Shallow Estuary in Northern China

Wind forcing controls on river plume spreading on a tropical continental shelf

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