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.
[3] Coastal erosion may be caused by hydraulic action, abrasion, impact and corrosion by wind and water, and other forces, natural or unnatural.
Softer areas become eroded much faster than harder ones, which typically result in landforms such as tunnels, bridges, columns, and pillars.
Attrition occurs when waves cause loose pieces of rock debris (scree) to collide with each other, grinding and chipping each other, progressively becoming smaller, smoother and rounder.
Solution is the process in which acids contained in sea water will dissolve some types of rock such as chalk or limestone.
The rate at which cliff fall debris is removed from the foreshore depends on the power of the waves crossing the beach.
The adjacent bathymetry, or configuration of the seafloor, controls the wave energy arriving at the coast, and can have an important influence on the rate of cliff erosion.
They interfere with the natural water currents and prevent sand from shifting along coasts, along with the high costs to install and maintain them, their tendency to cause erosion in adjacent beaches and dunes, and the unintended diversion of stormwater and into other properties.
[11] Natural forms of hard-erosion control include planting or maintaining native vegetation, such as mangrove forests and coral reefs.
[8] In some situations, beach nourishment is not a suitable measure to take for erosion control, such as in areas with sand sinks or frequent and large storms.
[10] Dynamic revetment, which uses loose cobble to mimic the function of a natural storm beach, may be a soft-erosion control alternative in high energy environments such as open coastlines.
[13] Over the years beach nourishment has become a very controversial shore protection measure: It has the potential to negatively impact several of the natural resources.
Solutions that have potential include native vegetation, wetland protection and restoration, and relocation or removal of structures and debris.
Living shorelines are found to be more resilient against storms, improve water quality, increase biodiversity, and provide fishery habitats.
Marshes and oyster reefs are examples of vegetation that can be used for living shorelines; they act as natural barriers to waves.
These relocation practices are very cost-efficient, can buffer storm surges, safeguard coastal homes and businesses, lower carbon and other pollutants, create nursery habitats for important fish species, restore open space and wildlife, and bring back the culture of these coastal communities.
Before-and-after comparisons can be made using data gathered by manual surveying, laser altimeter, or a GPS unit mounted on an ATV.
[16] Remote sensing data such as Landsat scenes can be used for large scale and multi year assessments of coastal erosion.
[21] Dunwich, the capital of the English medieval wool trade, disappeared over the period of a few centuries due to redistribution of sediment by waves.
Groynes and other artificial measures to keep it under control has only accelerated the process further down the coast, because longshore drift starves the beaches of sand, leaving them more exposed.
The coastline of North Cove, Washington has been eroding at a rate of over 100 feet per year, earning the area the nickname "Washaway Beach".
In El Campello, Spain, the erosion and failure of a Roman fish farm excavated from rock during the first century B.C.
Another reason Hampton-on-Sea had such a horrific case of coastal erosion is due to an increase in the frequency and the intensity of storms it experienced.
[11] These natural events had destroyed the Hampton Pier, Hernecliffe Gardens, a set of villas, several roads, and many other structures that once lay on Hampton-On-Sea.
