Coastal Erosion
Coastal erosion is the loss or displacement of land, or the long-term removal of sediment and rocks along the coastline.
It is due to the action of waves, currents, tides, wind-driven water, waterborne ice, or other impacts of storms.
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 happens in areas where there are strong winds, loose sand, and soft rocks.
The blowing of millions of sharp sand grains creates a sandblasting effect.
This effect helps to erode, smooth and polish rocks.
According to the IPCC, sea level rise caused by climate change will increase coastal erosion worldwide, significantly changing the coasts and low-lying coastal areas.
Control methods:
Hard-erosion controls:
Seawalls and groynes serve as semi-permanent infrastructure.
These structures are not immune from normal wear-and-tear and will have to be refurbished or rebuilt.
Natural forms of hard-erosion control include planting or maintaining native vegetation, such as mangrove forests and coral reefs.
Soft-erosion controls:
Soft erosion strategies refer to temporary options of slowing the effects of erosion.
These options, including Sandbag and beach nourishment, are not intended to be long-term solutions or permanent solutions.
Another method, beach scraping or beach bulldozing allows for the creation of an artificial dune in front of a building or as means of preserving a building foundation.
One of the most common methods of soft erosion control is beach nourishment projects.
These projects involve dredging sand and moving it to the beaches as a means of reestablishing the sand lost due to erosion.
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.
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