Longshore Drift Effects

1062 Words 5 Pages
Processes Explanation Photographic Evidence Impact on the area – Positive or negative
Longshore Drift Longshore drift is the lateral movement of sediment in the near shore zone on a coast. It is caused by wave induced currents and wind. This process occurs when the waves break at an angle to the shoreline therefore moving sand along the beach on a diagonal direction
The waves hit the beach at an angle (swash) and then retreat (backwash) an angle
If the wave is constructive, sediment will be added onto the beach
If the wave is destructive, sediment will be carried away from the beach and into the sea forming a sand bar.
On Palm Beach the wind direction was South East and the direction of marine sediment was in a south-east direction,
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 Longshore drift can form spits, barriers and tidal inlets.
 Groynes have been created to assist the buildup of sand on the beach and has then interfered with longshore drift
 Groynes a can destroy habitats
 The groyne stops the natural flow of sand to other beaches
 Due to the sea walls south of Palm Beach, longshore drift is restricted, and therefore a groyne was constructed to trap sand.
 Encourages the use of the beach
 Changes the width of the beach effecting recreational activities
 Groynes have been implemented to stop longshore drift to ensure buildup of sand on Palm beach therefore saving money for the future
 Longshore drift doesn’t always restore sand onto beach due to the seawalls south of Palm Beach therefore the government has to pump sand onto the beach costing over $1-3 for every cubic metre of sand annually
Erosion (wind/water) Erosion is the gradual breakdown and transportation of rock fragments from the earth’s surface.
Wind and weather conditions contribute to erosion (as they cause destructive waves which take away sand from the
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It is evident in constructive waves as these waves have less energy.
Deposition creates many landforms along the coastline, including, headlands and spits.
Furthermore, deposition hasn’t recently occurred on Palm Beach due to the storm generated waves which attack Palm Beach. Figure 15 Diagram of Constructive waves Retrieved from: alevelgeography.com

Retrieved from: Mackenzie’s Camera Roll, Palm Beach, July 2015 Overall has a positive effect on the land as it builds up the shoreline
 The beach width and form will constantly change (slower than erosion) as deposition builds up sediments from the constructive waves
 Buildup of beach will protect the primary dunes from erosion thereby protecting animal habitats and the infrastructure on coastline
 Palm Beach does not have enough deposition due to lack of constructive waves (in recent weeks)
 This makes Palm Beach vulnerable to further storms and bad weather conditions
 Increases the width of the beach therefore making it more appealing for recreation and tourists
 Aesthetic beauty of the beach is regained
 Property owners do not need to worry about their land being eroded

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