Longshore current
Topic: Landforms and their Evolution: Rivers, Groundwater, Glaciers, Waves and Wind · NCERT: Class 11, Ch 6 "Landforms and their Evolution"
Meaning
A longshore current is a current in the sea that flows parallel to the shore. Waves seldom hit a coast head-on. When they strike at an angle, part of their push is directed along the beach, and this sets up a current along the shore. The current carries sand and pebbles down the coast. This movement is called longshore drift. Where the coast bends or the water slows, the sand is dropped, building beaches, bars and spits. Harbour walls that block this current starve the coast beyond them of sand, which causes erosion.
Example
The Kakinada spit on the Godavari delta in Andhra Pradesh is a long finger of sand. Longshore currents carried the sand along the coast and built it up.
Don't confuse with
- Rip current: a rip current is a narrow, strong flow that rushes straight out to sea, away from the beach. A longshore current runs along the shore.
Related concepts
- Emergent coast
- Submergent coast
- Ria coast
- Coastal erosion
- Sea cliff
- Wave-cut platform
- Sea cave
- Sea arch
- Sea stack