Coastal erosion is the wearing away of the land by the sea. This often involves destructive waves wearing away the coast usually during storms. Waves erode the coastline in four main ways:

Hydraulic Action: Waves are strong enough to widen the cracks and joints by hydraulic action. When sea water enters with force into cracks in cliffs the air inside them will be pressed against the rocks. During the backwash of the wave the trapped air will expand releasing pressure from the rocks. The continuous change in pressure will finally weaken the rocks which break down into the sea.

Abrasion: Occurs as breaking waves which contain sand and larger fragments erode the shoreline or headland. It is commonly known as the sand paper effect. The force of the waves, laden with sand, pebbles and small stones continuously pound the rocks, erodes the base of the cliffs.

Attrition: This occurs when waves smash rocks and pebbles into each other. His material breaks up into smaller pieces becoming rounded and smooth pebbles and also fine sand.

Solution: This is the process by which salts and other acids contained in sea water will dissolve some types of rock such as chalk or limestone.

This video below explains clearly the four coastal erosion processes.

Now work out the worksheet entitled Coastal erosion Worksheet available in the resources section of this lesson.