Barrier bar
Also called: Barrier island · Topic: Landforms and their Evolution: Rivers, Groundwater, Glaciers, Waves and Wind · NCERT: Class 11, Ch 6 "Landforms and their Evolution"
Meaning
A barrier bar starts as an underwater sand ridge (an offshore bar). More and more sand is added until the ridge rises above the water. It often grows across a river mouth or the entrance of a bay. The calm water trapped behind it becomes a lagoon. Barriers act as a shield for the coast. Together with beaches, dunes and mangroves, they help protect the land from storm and tsunami waves.
Example
Sriharikota is a barrier island on the coast of Andhra Pradesh. It cuts off Pulicat lake from the Bay of Bengal, which makes Pulicat a lagoon.
Don't confuse with
- Offshore bar: this lies under water. A barrier bar has grown above the water.
- Spit: one end of a spit is joined to the land. A barrier bar runs along the coast, away from the shore.