Factors Affecting the Rate of Coastal Erosion
Factors affecting the rate of coastal erosion
Rock types - Soft rocks like clay or mud, erode faster than hard rocks like granite. This is because hard rocks are more resistant to erosion. This means that the hard rock is left sticking out into the sea as a headland. The headland is now vulnerable to the force of destructive waves but shelters the bays close by from further erosion.
Wave type - Destructive waves cause more erosion than constructive waves. This is because backwash is more powerful than swash. Therefore it removes more materials from the coast than are deposited on it.
Joints in the rocks - The more joints a rock has the more exposed it is to erosion, this is because air gets in the rock and when water gets into the joints it lubricates the rock and makes it slippery. This increased the weight and causes the block to fall off. The more joints there is, the weaker the rock is.
Rock arrangement - A coastline that is parallel to the coast is called a concordant or "Pacific" coastline. Whereas, one that runs at right angles to the coast is called a discordant or "Atlantic" coastline. If a coastline is a discordant coastline, it will erode faster as both soft and hard rock are exposed which will increase the rate of erosion and create headlands.
Breaking point of a wave - If a wave breaks at the foot of a cliff, it will transfer most of its energy to the cliff and cause the most erosion. But there would be less erosion if the wave breaks before it reaches the cliff, as the energy would not be transferred.
Fetch of a wave - If a wave has a longer fetch it will cause the most erosion as the wave itself will be higher and steeper. This means it will have more energy.
Width of a beach - Beaches slow down waves, therefore they reduce the erosive power of a wave. This means that a wide, flat beach will protect the cliffs more than a narrow, steep beach as it will take longer for the wave to reach the cliff. Which reduces the erosive power as it will
Rock types - Soft rocks like clay or mud, erode faster than hard rocks like granite. This is because hard rocks are more resistant to erosion. This means that the hard rock is left sticking out into the sea as a headland. The headland is now vulnerable to the force of destructive waves but shelters the bays close by from further erosion.
Wave type - Destructive waves cause more erosion than constructive waves. This is because backwash is more powerful than swash. Therefore it removes more materials from the coast than are deposited on it.
Joints in the rocks - The more joints a rock has the more exposed it is to erosion, this is because air gets in the rock and when water gets into the joints it lubricates the rock and makes it slippery. This increased the weight and causes the block to fall off. The more joints there is, the weaker the rock is.
Rock arrangement - A coastline that is parallel to the coast is called a concordant or "Pacific" coastline. Whereas, one that runs at right angles to the coast is called a discordant or "Atlantic" coastline. If a coastline is a discordant coastline, it will erode faster as both soft and hard rock are exposed which will increase the rate of erosion and create headlands.
Breaking point of a wave - If a wave breaks at the foot of a cliff, it will transfer most of its energy to the cliff and cause the most erosion. But there would be less erosion if the wave breaks before it reaches the cliff, as the energy would not be transferred.
Fetch of a wave - If a wave has a longer fetch it will cause the most erosion as the wave itself will be higher and steeper. This means it will have more energy.
Width of a beach - Beaches slow down waves, therefore they reduce the erosive power of a wave. This means that a wide, flat beach will protect the cliffs more than a narrow, steep beach as it will take longer for the wave to reach the cliff. Which reduces the erosive power as it will