The sudden abandonment of an existing tidal channel in favour of a newly formed channel. The tidal levels and water motion which would result from Earth's rotation and gravitational effects of, in particular, the Earth, Sun and Moon, without any atmospheric influences. This process may occur at places where beach or seabed material is a mixture of fine and coarse sediments (so-called graded sediment, see Coastal and marine sediments). The natural process of removing fine sediment from the beach or seabed top layer, leaving coarse material behind, thus leading to a more erosion-resistant residual top layer.intended to prevent damage of properties situated on the coast
Manmade structures such as seawalls, revetments, bulkheads, geotubes, etc.Poorly permeable underground layer that limits the flow of groundwater from one aquifer to another.Īn aquifuge is an absolutely impermeable unit that will not transmit any water.Īn aquiclude is a formation that has very low hydraulic conductivity and hardly transmits water. Underground layer of water-bearing permeable rock, rock fractures or unconsolidated materials (gravel, sand, or silt).Ī confined aquifer is an aquifer that is overlain by a confining poorly permeable layer.Īn unconfined aquifer is an aquifer extending from the base of the aquifer to the land surface. The deep water angle of incidence is often denoted \alpha_0. See: Shallow-water wave theory, Wave transformation. When waves enter shallow water, the wave propagation direction tends to become perpendicular to the depth contours, by refraction. The angle between the wave propagation direction and the normal to the coastline or the angle between the wave front and the coastline (often denoted by the symbol \alpha or \theta). See: Active coastal zone.ĭeposit rock material formed when streams run off mountains to plains below. In the case of a dune coast the front dune is part of the active coastal zone. It extends from the closure depth up to a fixed land boundary (rock, cliff, seawall, sea dike).
The active coastal zone (also called active coastal profile) is the cross-shore coastal zone that is highly dynamic, with up and down redistribution of sand by the action of tides, waves and wind. Growth (vertical and/or horizontal) of morphological structures ( beach, bar, dune, sand bank, tidal flat, salt marsh, tidal channel, etc.) by sedimentation. The erosive action that occurs when rock particles of varying sizes are dragged over or hurled against a surface. Definition of coastal sub-zones, adapted from the Shore Protection Manual, 1984 Abrasion
0 kommentar(er)
