Longshore Drift

Introduction

• Longshore drift is a coastal process that involves the movement of sediment along the shoreline due to the action of waves and currents.
• Understanding longshore drift is crucial in coastal geography and the study of landform development.

Process of Longshore Drift

• Wave Action: Breaking waves approach the shore at an angle.
• Swash: The wave rushes up the beach at an angle, carrying sediment with it.
• Backwash: The water retreats perpendicular to the beach, carrying sediment back to the sea.
• Net Movement: Over time, the net movement of sediment is along the shoreline, parallel to the coast.

Factors Affecting Longshore Drift

• Wave Angle: The angle at which waves approach the coast affects the direction of longshore drift.
• Beach Gradient: The steepness of the beach slope can influence the speed and extent of longshore drift.
• Obstacles: Natural or human-made structures can disrupt or redirect longshore drift.

Landforms Associated with Longshore Drift

• Spits: Long, narrow landforms that extend into the sea, formed by the accumulation of sediment carried by longshore drift.
• Bars: Submerged or partially submerged ridges of sediment formed offshore by the deposition of transported material.

Significance of Longshore Drift

• Landform Evolution: Longshore drift plays a significant role in shaping coastal landforms, including beaches, spits, and bars.
• Coastal Erosion and Deposition: It can contribute to both erosion and deposition, affecting coastal stability.

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Longshore Drift

Summary

• Longshore drift is the movement of sediment along the shoreline due to wave action and currents.
• It shapes coastal landforms, impacts erosion and deposition, and has implications for coastal management. Understanding this process is essential in coastal geography.