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Beach Morphodynamics
Coastal morphodynamics (i.e. the dynamics of beach morphology) refers to the study of the interaction and adjustment of the seafloor topography and fluid hydrodynamic processes, seafloor morphologies and sequences of change dynamics involving the motion of sediment. Hydrodynamic processes include those of waves, tides and wind-induced currents. While hydrodynamic processes respond instantaneously to morphological change, morphological change requires the redistribution of sediment. As sediment takes a finite time to move, there is a lag in the morphological response to hydrodynamic forcing. Sediment can therefore be considered to be a time-dependent coupling mechanism. Since the boundary conditions of hydrodynamic forcing change regularly, this may mean that the beach never attains equilibrium. Morphodynamic processes exhibit positive and negative feedbacks (such that beaches can, over different timescales, be considered to be both self-forcing and self-organised systems), no ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beach
A beach is a landform alongside a body of water which consists of loose particles. The particles composing a beach are typically made from rock, such as sand, gravel, shingle, pebbles, etc., or biological sources, such as mollusc shells or coralline algae. Sediments settle in different densities and structures, depending on the local wave action and weather, creating different textures, colors and gradients or layers of material. Though some beaches form on inland freshwater locations such as lakes and rivers, most beaches are in coastal areas where wave or current action deposits and reworks sediments. Erosion and changing of beach geologies happens through natural processes, like wave action and extreme weather events. Where wind conditions are correct, beaches can be backed by coastal dunes which offer protection and regeneration for the beach. However, these natural forces have become more extreme due to climate change, permanently altering beaches at very rapid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Raised Beach
A raised beach, coastal terrace,Pinter, N (2010): 'Coastal Terraces, Sealevel, and Active Tectonics' (educational exercise), from 2/04/2011/ref> or perched coastline is a relatively flat, horizontal or gently inclined surface of marine origin,Pirazzoli, PA (2005a): 'Marine Terraces', in Schwartz, ML (ed) ''Encyclopedia of Coastal Science.'' Springer, Dordrecht, pp. 632–633 mostly an old abrasion platform which has been lifted out of the sphere of wave activity (sometimes called "tread"). Thus, it lies above or under the current sea level, depending on the time of its formation.Strahler AH; Strahler AN (2005): ''Physische Geographie.'' Ulmer, Stuttgart, 686 p.Leser, H (ed)(2005): ‚''Wörterbuch Allgemeine Geographie.'' Westermann&Deutscher Taschenbuch Verlag, Braunschweig, 1119 p. It is bounded by a steeper ascending slope on the landward side and a steeper descending slope on the seaward side (sometimes called "riser"). Due to its generally flat shape, it is often used for a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blowhole (geology)
In geology, a blowhole or marine geyser is formed as sea caves grow landwards and upwards into vertical shafts and expose themselves towards the surface, which can result in hydraulic compression of sea water that is released through a port from the top of the blowhole. The geometry of the cave and blowhole along with tide levels and swell conditions determine the height of the spray. Mechanics Blowholes are likely to occur in areas where there are crevices, such as lava tubes, in rock along the coast. These areas are often located along fault lines and on islands. As powerful waves hit the coast, water rushes into these crevices and bursts out in a high pressured release. It is often accompanied by a loud noise and wide spray, and for this reason, blowholes are often sites of tourism. Marine erosion on rocky coastlines produce blowholes that are found throughout the world. They are found at intersecting faults and on the windward sides of a coastline where they receive highe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bioerosion
Bioerosion describes the breakdown of hard ocean substrates – and less often terrestrial substrates – by living organisms. Marine bioerosion can be caused by mollusks, polychaete worms, phoronids, sponges, crustaceans, echinoids, and fish; it can occur on coastlines, on coral reefs, and on ships; its mechanisms include biotic boring, drilling, rasping, and scraping. On dry land, bioerosion is typically performed by pioneer plants or plant-like organisms such as lichen, and mostly chemical (e.g. by acidic secretions on limestone) or mechanical (e.g. by roots growing into cracks) in nature. Bioerosion of coral reefs generates the fine and white coral sand characteristic of tropical islands. The coral is converted to sand by internal bioeroders such as algae, fungi, bacteria (microborers) and sponges (Clionaidae), bivalves (including '' Lithophaga''), sipunculans, polychaetes, acrothoracican barnacles and phoronids, generating extremely fine sediment with diameters of 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Erosion
Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is distinct from weathering which involves no movement. Removal of rock or soil as clastic sediment is referred to as ''physical'' or ''mechanical'' erosion; this contrasts with ''chemical'' erosion, where soil or rock material is removed from an area by dissolution. Eroded sediment or solutes may be transported just a few millimetres, or for thousands of kilometres. Agents of erosion include rainfall; bedrock wear in rivers; coastal erosion by the sea and waves; glacial plucking, abrasion, and scour; areal flooding; wind abrasion; groundwater processes; and mass movement processes in steep landscapes like landslides and debris flows. The rates at which such processes act control how fast a surface is eroded. Typically, physical erosion procee ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coastal And Estuarine Research Federation
The Coastal and Estuarine Research Federation (CERF) is a private, nonprofit organization that was created in 1971. At that time, the members of two regionally based organizations, the Atlantic Estuarine Research Society (AERS) and the New England Estuarine Research Society (NEERS) recognized the need for a third estuarine organization that would address national (now worldwide) estuarine and coastal issues. Today, CERF is a multidisciplinary federation of members and seven regionally based affiliate societies dedicated to the understanding and wise stewardship of estuaries and coasts worldwide. Mission CERF advances understanding and wise stewardship of estuarine and coastal ecosystems worldwide. Its mission is to: https://www.cerf.science/about-us *Promote research in estuarine and coastal ecosystems *Support education of scientists, decision-makers and the public *Facilitate communication among these groups Membership in CERF is open to all who support these goals. The Fe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coastal Engineering
Coastal engineering is a branch of civil engineering concerned with the specific demands posed by constructing at or near the coast, as well as the development of the coast itself. The hydrodynamic impact of especially waves, tides, storm surges and tsunamis and (often) the harsh environment of salt seawater are typical challenges for the coastal engineer – as are the morphodynamic changes of the coastal topography, caused both by the autonomous development of the system and man-made changes. The areas of interest in coastal engineering include the coasts of the oceans, seas, marginal seas, estuaries and big lakes. Besides the design, building and maintenance of coastal structures, coastal engineers are often interdisciplinary involved in integrated coastal zone management, also because of their specific knowledge of the hydro- and morphodynamics of the coastal system. This may include providing input and technology for e.g. environmental impact assessment, port development, st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coastal Geography
Coastal geography is the study of the constantly changing region between the ocean and the land, incorporating both the physical geography (i.e. coastal geomorphology, climatology and oceanography) and the human geography (sociology and history) of the coast. It includes understanding coastal weathering processes, particularly wave action, sediment movement and weather, and the ways in which humans interact with the coast. Wave action and longshore drift The waves of different strengths that constantly hit against the shoreline are the primary movers and shapers of the coastline. Despite the simplicity of this process, the differences between waves and the rocks they hit result in hugely varying shapes. The effect that waves have depends on their strength. Strong waves, also called destructive waves, occur on high-energy beaches and are typical of winter. They reduce the quantity of sediment present on the beach by carrying it out to bars under the sea. Constructive, weak waves ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coastal Erosion
Coastal erosion is the loss or displacement of land, or the long-term removal of sediment and rocks along the coastline due to the action of waves, currents, tides, wind-driven water, waterborne ice, or other impacts of storms. The landward retreat of the shoreline can be measured and described over a temporal scale of tides, seasons, and other short-term cyclic processes. Coastal erosion may be caused by hydraulic action, abrasion, impact and corrosion by wind and water, and other forces, natural or unnatural. On non-rocky coasts, coastal erosion results in rock formations in areas where the coastline contains rock layers or fracture zones with varying resistance to erosion. Softer areas become eroded much faster than harder ones, which typically result in landforms such as tunnels, bridges, columns, and pillars. Over time the coast generally evens out. The softer areas fill up with sediment eroded from hard areas, and rock formations are eroded away. Also erosion commonly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coastal Development Hazards
A coastal development hazard is something that affects the natural environment by human activities and products. As coasts become more developed, the vulnerability component of the equation increases as there is more value at risk to the hazard. The likelihood component of the equation also increases in terms of there being more value on the coast so a higher chance of hazardous situation occurring. Fundamentally humans create hazards with their presence. In a coastal example, erosion is a process that happens naturally on the Canterbury Bight as a part of the coastal geomorphology of the area and strong long shore currents. This process becomes a hazard when humans interact with that coastal environment by developing it and creating value in that area. A natural hazard is defined as the release of energy or materials that threaten humans or what they value. In a coastal context these hazards vary temporally and spatially from a rare, sudden, massive release of energy and materials s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Landforms
A landform is a natural or anthropogenic land feature on the solid surface of the Earth or other planetary body. Landforms together make up a given terrain, and their arrangement in the landscape is known as topography. Landforms include hills, mountains, canyons, and valleys, as well as shoreline features such as bays, peninsulas, and seas, including submerged features such as mid-ocean ridges, volcanoes, and the great ocean basins. Physical characteristics Landforms are categorized by characteristic physical attributes such as elevation, slope, orientation, stratification, rock exposure and soil type. Gross physical features or landforms include intuitive elements such as berms, mounds, hills, ridges, cliffs, valleys, rivers, peninsulas, volcanoes, and numerous other structural and size-scaled (e.g. ponds vs. lakes, hills vs. mountains) elements including various kinds of inland and oceanic waterbodies and sub-surface features. Mountains, hills, plateaux, and plains are the fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coastal Management
Coastal management is defence against flooding and erosion, and techniques that stop erosion to claim lands. Protection against rising sea levels in the 21st century is crucial, as sea level rise accelerates due to climate change. Changes in sea level damage beaches and coastal systems are expected to rise at an increasing rate, causing coastal sediments to be disturbed by tidal energy. Coastal zones occupy less than 15% of the Earth's land area, while they host more than 40% of the world population. Nearly 1.2 billion people live within 100 km of shoreline and 100 m of sea level, with an average density 3 times higher than the global average for population. With three-quarters of the world population expected to reside in the coastal zone by 2025, human activities originating from this small land area will impose heavy pressure on coasts. Coastal zones contain rich resources to produce goods and services and are home to most commercial and industrial activities. Histor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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