There are a number of ways that coastal regions can be eroded, the processes are as follows: (Key words for each process are in italic)
1. Hydraulic Action: The constant force of the waves causes pressure against the cliff face
2. Abrasion: The process of small rocks and pebbles smashing against the cliff face. The eroded particles scrape and remove small pieces of the cliff
3. Attrition: Rocks and pebbles smash together and break eachother apart into smaller pieces
4. Solution: Weak acid in the water dissolves the rocks
A DESTRUCTIVE wave has a weak swash and a strong backwash and erodes the coastline as it drags material away from the shoreline
Coastal Management aims to prevent coastlines being eroded - Soft Engineering works with the land and is environmentally friendly. Beach Nourishment (replacing eroded materal) and Managed Retreat (Allowing the coastline to erode naturally) are different types.
Other coastal defence solutions are Hard Engineering which are more costly and visual. They include - Groynes, which is a structrue built at a right angle to the shore to 'catch' material moved by Longshore Drift. A Sea Wall is built infront on coastal attractions to prevent the force of the waves impacting. Rock armour is rocks/other material placed at the base of cliffs and have small gaps between the rocks to absorb the waves energy rather than the cliff face. Boulders and rocks are wired into cages and placed infront on vunerable areas.
Erosion - Coastal Landforms
Many coastline features are created by erosion:
Weathering on cliffs causes landforms. The force of the waves at the base of a cliff eventually cause a Wave Cut Notch - a gap at the base of a cliff. This process repeats until the weight of the cliff is no longer supported so it collapses. The backwash of the waves carries the sediment back to the sea creating a Wave Cut Platform - a flat area caused by the cliff material
Headlands/Bays can be created when there is a mixture of hard/soft rock in a cliff. The soft rock will erode quicker and retreat faster than the harder rock, which is sticking out to sea. Crack, Cave, Arch, Stack, Stump - Pressure of waves against a cliff face eventually cause a crack in the rock, over time this then causes a cave, when the sea has eroded all the way through an arch is formed. When the arch can no longer be supported, the top part collapses leaving a stack. A wave cut notch develops and this also collapses leaving a stump. (Eg: Old Harry, Dorset)
Deposition - Coastal Landforms
Beaches are formed when eroded material is transported by the waves then deposited in an area. Over time this builds up to create a beach.
Longshore Drift is where the waves move eroded pieces of material along the beach and then deposit them. A coastal feature due to this is a Spit, which is a curved piece of land from a beach, created by sediment/eroded material.
Others include a Sand Bar, which joins two headlands together and a Tombolo is when an island is joined to the mainland by a spit.