Coastal morphodynamicsCoastal 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.
Coastal development hazardsA 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.
Coastal sediment supplyCoastal sediment supply is the transport of sediment to the beach environment by both fluvial and aeolian transport. While aeolian transport plays a role in the overall sedimentary budget for the coastal environment, it is paled in comparison to the fluvial supply which makes up 95% of sediment entering the ocean. When sediment reaches the coast it is then entrained by longshore drift and littoral cells until it is accreted upon the beach or dunes. While it is acknowledged that storm systems are the driver behind coastal erosion.
Longshore driftLongshore drift from longshore current is a geological process that consists of the transportation of sediments (clay, silt, pebbles, sand, shingle) along a coast parallel to the shoreline, which is dependent on the angle of incoming wave direction. Oblique incoming wind squeezes water along the coast, and so generates a water current which moves parallel to the coast. Longshore drift is simply the sediment moved by the longshore current. This current and sediment movement occur within the surf zone.
MangroveA mangrove is a shrub or tree that grows mainly in coastal saline or brackish water. Mangroves grow in an equatorial climate, typically along coastlines and tidal rivers. They have special adaptations to take in extra oxygen and to remove salt, which allow them to tolerate conditions that would kill most plants. The term is also used for tropical coastal vegetation consisting of such species. Mangroves are taxonomically diverse, as a result of convergent evolution in several plant families.
SeawallA seawall (or sea wall) is a form of coastal defense constructed where the sea, and associated coastal processes, impact directly upon the landforms of the coast. The purpose of a seawall is to protect areas of human habitation, conservation, and leisure activities from the action of tides, waves, or tsunamis. As a seawall is a static feature it will conflict with the dynamic nature of the coast and impede the exchange of sediment between land and sea.
Integrated coastal zone managementIntegrated coastal zone management (ICZM), integrated coastal management (ICM), or integrated coastal planning is a coastal management process for the management of the coast using an integrated approach, regarding all aspects of the coastal zone, including geographical and political boundaries, in an attempt to achieve sustainability. This concept was born in 1992 during the Earth Summit of Rio de Janeiro. The specifics regarding ICZM is set out in the proceedings of the summit within Agenda 21, Chapter 17.
GroyneA groyne (in the U.S. groin) is a rigid hydraulic structure built perpendicularly from an ocean shore (in coastal engineering) or a river bank, interrupting water flow and limiting the movement of sediment. It is usually made out of wood, concrete, or stone. In the ocean, groynes create beaches, prevent beach erosion caused by longshore drift where this is the dominant process and facilitate beach nourishment. There is also often cross-shore movement which if longer than the groyne will limit its effectiveness.
Breakwater (structure)A breakwater is a permanent structure constructed at a coastal area to protect against tides, currents, waves, and storm surges. Part of a coastal management system, breakwaters are installed to minimize erosion, and to protect anchorages, helping isolate vessels within them from marine hazards such as prop washes and wind-driven waves. A breakwater, also known in some contexts as a jetty, may be connected to land or freestanding, and may contain a walkway or road for vehicle access.
Hard engineeringHard engineering involves the construction of hydraulic structures to protect coasts from erosion. Such structures include seawalls, gabions, breakwaters, groynes and tetrapods. Hard engineering can cause unintended environmental consequences, such as new erosion and altered sedimentation patterns, that are detrimental to the immediate human and natural environment or along down-coast locations and habitats. Seawalls and bulkheads may have multiple negative effects on nearshore ecosystems due to the way they reflect wave energy instead of dissipating it.
