Salinity and Tides in Alluvial Estuaries

Author: H.H.G. Savenije
Publisher: Elsevier
ISBN: 9780080461618
Format: PDF
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The book describes an integrated theory that links estuary shape to tidal hydraulics, tidal mixing and salt intrusion. The shape of an alluvial estuary is characterised by exponentially varying width and the absence of bottom slope. This topography is closely related to tidal parameters, hydraulic parameters and parameters that describe 1-dimensional mixing and salt intrusion. Starting from the fundamental equations for conservation of mass and momentum, analytical equations are derived that relate the topography to tidal parameters (tidal excursion, phase lag, tidal damping, tidal amplification), wave celerity, lateral and vertical mixing and salt intrusion. The book presents a review of the state of the art, a comprehensive theoretical background and ample case illustrations from all over the world. It provides tools with which human interference in estuary dynamics can be described and predicted, resulting from, for instance: upstream fresh water abstraction, dredging, climate change or sea-level rise. In describing the interactions between tide, topography, water quality and river discharge, it provides useful information for hydraulic engineers, morphologists, ecologists and people concerned with water quality in alluvial estuaries. Although the book can be used as a text book, it is mainly a monograph aimed at graduate students and researchers. * Provides new integrated theory for tidal hydraulics, tidal mixing and salt intrusion in alluvial estuaries * Presents a consistent set of analytical equations to compute tidal movement, tidal mixing and salt intrusion, derived from the fundamental laws of conservation of mass and momentum * Serves as a practical guide with many illustrations of applications in real estuaries

Modeling morphodynamic evolution in alluvial estuaries

Author: Mick van der Wegen
Publisher: CRC Press
ISBN: 0203093348
Format: PDF, ePub, Mobi
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The main objective of this research is to investigate the governing processes and characteristics that drive morphodynamic evolution in alluvial estuaries by application of a process-based numerical model (Delft3D). It is of utmost importance to understand estuarine processes so that impact of human interference (like dredging and land reclamation) and long-term changes (like sea level rise) can be evaluated. The research addresses a number of cases ranging from an rectangular basins to real estuaries like the Western Scheldt in the Netherlands or San Pablo Bay in California. The more schematized approach allow to study morphodynamic evolution over several millennia under constant forcing and answers more fundamental questions related to conditions of equilibrium and related time scales. The more realistic cases give insight into the skill of the approach in predicting decadal morphodynamic developments. More processes are included to mimic realistic conditions and model results are compared to bathymetric measurements over the last century. The research shows that the modeling approach is good capable of describing stable morphodynamic calculations over a timescale of millennia with patterns similar to patterns observed in reality. Additionally, the approach shows that it is possible to predict decadal morphodynamic developments in real estuaries with significant skill.

Salt Intrusion Tides and Mixing in Multi Channel Estuaries

Author: Anh Duc Nguyen
Publisher: CRC Press
ISBN: 9781439828342
Format: PDF, Kindle
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Multi-channel estuaries, such as the Mekong Delta in Vietnam and the Scheldt in the Netherlands, have characteristics of both the river and the sea, forming a unique environment influenced by tidal movements of the sea and freshwater flow of the river. This study addresses a number of knowledge gaps in multi-channel estuaries by developing a predictive analytical approach for salinity intrusion and discharge estimate in multi-channel estuaries. The new approach agrees well with 1-D hydrodynamic models and observations, indicating its applicability in practice. Most importantly, the study has successfully developed a new theory and a new equation to quantify tidal pumping due to ebb-flood channel residual circulation and the related salt dispersion.

Contributions to Modern and Ancient Tidal Sedimentology

Author: Bernadette Tessier
Publisher: John Wiley & Sons
ISBN: 1119218381
Format: PDF, ePub, Mobi
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Tidal deposits have been a specific research topic for about 40 years, and whilst this has resulted in a proliferation of papers in scientific journals, there have only been a few book-length syntheses. Over the years, tidal sedimentology has been reinforced by fluid mechanics and numerical modelling but has remained rooted in facies and stratigraphic studies. Recent developments in tidal sedimentology lean toward a more quantitative assessment of the imprint of tides in the facies record of intertidal and shallow subtidal areas. They highlight the increasing relevance of tidal deposits studies, from high resolution subsurface reservoir geology to climate change and sea-level rise. This volume gathers 17 contributions to the Tidalites 2012 congress held in Caen, France. It reflects current advances in the sedimentology and stratigraphy of tidal deposits, in both ancient and modern environments. It shows the current diversity of this field of research, through a wide spectrum of methods including remote sensing, in-situ hydrodynamical measurements, and ichnology, in addition to classic field studies and petrography.

Modelling Approaches to Understand Salinity Variations in a Highly Dynamic Tidal River

Author: Ali Dinar Abdullah
Publisher: CRC Press
ISBN: 1351652532
Format: PDF, Docs
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This book reports the first systematic monitoring and modelling study on water availability, water quality and seawater intrusion of the Shatt al-Arab River (SAR) on the border of Iraq and Iran, where causes and concentration levels of salinity have not yet been fully understood, let alone addressed, leading to conflicting perceptions of its origin (external or internal), the natural conditions and the practices that can explain the current critical conditions. Current scientific knowledge on the SAR salinity problem is deficient, partially due to the complex and dynamic interaction between marine and terrestrial salinity sources, including return flows by water users of the different water sectors in the Euphrates and Tigris rivers upstream of the SAR. The development of a new series of monitoring stations and various modelling approaches helped to better understand the interactions between these different sources. The comprehensive and detailed dataset formed the basis for a validated analytical model that can predict the extent of seawater relative to other salinity sources in an estuary, and for a hydrodynamic model that can predict salinity changes. The adaptability of the models to changing conditions makes them directly applicable by water managers. The procedure can be applied to other comparable systems.

Oceanography and Marine Biology

Author: R.N. Hughes
Publisher: CRC Press
ISBN: 1315351560
Format: PDF, ePub, Docs
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Ever-increasing interest in oceanography and marine biology and their relevance to global environmental issues create a demand for authoritative reviews summarizing the results of recent research. Oceanography and Marine Biology: An Annual Review has catered to this demand since its founding by the late Harold Barnes more than 50 years ago. Its objectives are to consider, annually, the basic areas of marine research, returning to them when appropriate in future volumes; to deal with subjects of special and topical importance; and to add new subjects as they arise. The favourable reception and complimentary reviews accorded to all the volumes shows that the series is fulfilling a very real need. Volume 54 follows closely the objectives and style of the earlier volumes, continuing to regard the marine sciences—with all their various aspects—as a unity. Physical, chemical, and biological aspects of marine science are dealt with by experts actively engaged in these fields. The series is an essential reference text for researchers and students in all fields of marine science and related subjects, and it finds a place in libraries of universities, marine laboratories, research institutes and government departments. It is consistently among the highest ranking series in terms of impact factor in the marine biology category of the citation indices compiled by the Institute for Scientific Information/Web of Science.

Estuarine and Coastal Hydrography and Sediment Transport

Author: R. J. Uncles
Publisher: Cambridge University Press
ISBN: 1107040981
Format: PDF, ePub
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A practical guide to the latest techniques to measure sediments, seabed, water and transport mechanisms in estuaries and coastal waters. Covering a broad range of topics, enough background is included to explain how each technology functions. A review of recent fieldwork experiments demonstrates how modern methods apply in real-life scenarios.

Lagoons of Sri Lanka

Author: Silva, E. I. L.
Publisher: IWMI
ISBN: 9290907789
Format: PDF
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Sri Lanka, an island in the Indian Ocean, has lagoons along 1,338 km of its coastline. They experience low-energy oceanic waves and semidiurnal microtidal currents. The Sri Lankan coastal lagoons are not numerous but they are diverse in size, shape, configuration, ecohydrology, and ecosystem values and services. The heterogeneous nature, in general, and specific complexities, to a certain extent, exhibited by coastal lagoons in Sri Lanka are fundamentally determined by coastal and adjoining hinterland geomorphology, tidal fluxes and fluvial inputs, monsoonal-driven climate and weather, morphoedaphic attributes, and cohesive interactions with human interventions.Most coastal lagoons in Sri Lanka are an outcome of mid-Holocene marine transgression and subsequent barrier formation and spit development enclosing the water body between the land and the sea. This process has varied from one coastal stretch to another due to wave-derived littoral drift, sediment transport by tidal fluxes, fluvial inputs and wave action or, in other words, sea-level history, shore-face dynamics and tidal range as the three major factors that control the origin and maintenance of the sandy barrier, the most important features for the formation and evolution of coastal lagoons with their landward water mass. In certain stretches of Sri Lanka’s coastline, formation of the barrier spit was very active due to shore-face dynamics that resulted in chains of shore parallel, elongated lagoons. They are among the most productive in terms of ecosystem yield and show some similarities to large tropical lagoons with respect to sea entrance, zonation, biodiversity and ecosystem services. However, some of them become seasonally hypersaline due to lack of freshwater input and high evaporation. Functions and processes of some of these water bodies are fairly known. There are a fair number of small back-barrier lagoons of different shapes and sizes whose origin goes back to sea-level history. They are located on low-energy coasts with prominent beach ridges and restricted hinterland geomorphology. Mixing processes of these landward indentations are hindered by elevated sand dunes, and their salinity increases due to poor freshwater input and high evaporation leading to seasonally hypersaline conditions. These sedimented lagoons, primarily confined to the southeastern coast of the island, are biologically the least productive, with limited ecosystem values and services. Another group of moderately elongated semicircular, slightly large lagoons in the same coast, formed exclusively by submergence due to mid-Holocene sea-level rises, do not receive sufficient freshwater input leading to seasonally hypersaline conditions. They are also biologically unproductive but some are ecologically important since they provide habitats conducive to migratory birds. In contrast, some lagoons on the southern coast receive sufficient freshwater via streams draining the wet zone, maintain more estuarine salinities, exhibit rich biodiversity and serve as functional resource units. Lagoons formed by mid-Holocene submergence and recession of water level with simultaneous chain barrier formation on the high energy southwest coast, which includes cliffs, small bays and headlands, show peculiar configurations and link channel characteristics. Some of these irregular water bodies have clusters of small isles and luxuriant mangrove swamps with high biodiversity but not very rich in catadromous finfish and shellfish species due to the restricted nature of the entrance channel and nondistinct salinity gradients. The barrier-built, seasonally hypersaline lagoon complex in the Jaffna Peninsula, the largest lagoon system in the country with multiple perennial entrances show extremely narrow salinity ranges towards the upper limit of salinity. The main lagoon is elongated and the shore parallel to eastward and southward extensions is connected by narrow channels. The other lagoon in the Jaffna Peninsula is elongated, shore parallel and ribbon-shaped and receives tidal water throughout the year but freshwater is received only from precipitation and surface runoff. Even though the lagoons in the peninsula are extremely rich in ecosystem heterogeneity their hydrology and hydrodynamics have been severely disturbed by infrastructural development for transportation and by attempts to create a freshwater river for Jaffna. There are a few virgin lagoons of moderate size also on the northern coast, south of the Jaffna Peninsula on both the east and west sides. They look very typical tropical lagoons rich in biodiversity and biological production but their structure, functions and values are virtually unknown in scientific or socioeconomic terms. The lagoons located on the east coast are not numerous but relatively large in extent. They are also an outcome not only of mid-Holocene sea-level rises but of submerged multi-delta valleys or abandoned paleo estuaries. When inundated, the multi-delta valley configuration became elongated and is shore parallel with a smooth seaward shoreline; both shorelines become irregular when coastal waves are weak, and internal waves are created by the action of local winds. Configuration of a lagoon formed by inundation of an abandoned river valley is irregular with a long entrance channel extended landward. These lagoons are highly productive with a variety of associated ecosystems, large open water areas and wide perennial sea entrances. When the lagoon is too much elongated, zonation is prominent due to fewer entrance effects. Lagoons form a particular type of natural capital which generates use values (fish, shrimp, fuelwood, salt, fodder, ecotourism, anchorage, recreation, etc.) and nonuse values (habitat preservation, biodiversity, ecosystem linkages, etc.) contributing positively towards improving the human well-being. Of many values of lagoons in Sri Lanka, only the extractive values are generally utilized at present, by way of fish and shrimp catches, salt production and use of mangrove for various purposes. Besides, coastal lagoons generate a range of nonextractive use values and nonuse values, which could add towards the total economic value. Misuse has taken place at several instances when “use” adversely affects the status of the resources or the health of the ecosystem due to vulnerability and poverty, population pressure, urbanization, development activities and multi-stakeholder issues. The status of lagoon resources shows that the resources in the majority of Sri Lankan lagoons still remain satisfactory, somewhat good or very good. Nevertheless, concerns for management of lagoons in Sri Lanka exist only where “use values” (extractive values, such as fish and shrimp) exist. There is no evidence of resources management in lagoons for inspirational, scholarly values or tacit knowledge of the same. Management for use values exhibits several stages from zero management to comanagement via community management and state intervention. Most of Sri Lanka’s lagoons have the potential for generating high extractive and nonextractive use values which could improve the human well-being, while maintaining resources sustainability. Unfortunately, these potentials have not been understood or “seen” yet by the relevant authorities, although a few instances of exploring this potential were noticed.

Coastal Hazards Related to Storm Surge

Author: Rick Luettich
Publisher: MDPI
ISBN: 303842711X
Format: PDF, ePub, Mobi
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This book is a printed edition of the Special Issue "Coastal Hazards Related to Storm Surge" that was published in JMSE