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Indian Geography / Physiography

Coastal Plains and Islands of India


    Coastal plains and islands of India are the areas which are either connected to or surrounded by the sea. The coastal plains in India are the plains that are on the shores of the seas surrounding the Peninsular India. The plains along the shores of Arabian sea are called Western coastal plains and the plains along the shores of Bay of Bengal are called Eastern coastal plains. The plains in the West coast are narrower when compared to East coast because the slopes of Western Ghats are steep when compared to Eastern Ghats. As the slopes are gentle in Eastern Ghats, the rivers running over these, flow gently and deposit sediments in large volume.

    Western Coastal Plains

    • These are a narrow belt of plains having the width of 10-25 km between the Arabian sea and the Western Ghats and having a length around 1500 km. They are narrower in Karnataka and broader in Kerala.
    • These plains are further subdivided into Kerala, Karnataka, Konkan and Gujarat plains. These are plains of submergence, e.g. Dwaraka. Arabian sea is encroaching the land. But in Malabar plains, emergence of land is being found, which is an exception.
    • These plains are drained by short streams and we do not find deltas here. We can find many lagoons here.
    • The coastline is fractured like sawtooth. Many ports are located in the Western coast because of this sawtooth structure. All the harbours here are natural.
    • Numerous Creeks and Marshes are found in Gujarat, e.g. Sir Creek. Kandla, a tidal port, is located on a creek.
    • The Back waters that are found here, are called Kayals.

    Eastern Coastal Plains

    • These plains are wider and have an average width of 80-100 km between Eastern Ghats and Bay of Bengal. These plains can further be subdivided depending on the place where they are located in like Utkal plains, Andhra plains, Tamil Nadu plains, etc.
    • As many rivers in the Indian peninsula drain eastwards, large and fertile deltas can be found in the Eastern plains. These deltas are highly irrigated and are having dense population.
    • Here, we do not find many lagoons and good number of ports are also absent. Here, the only natural harbour is Visakhapatnam.
    • These are Emergent or Expansion plains because of receding of Bay of Bengal. New Moore island is an example of emergent coastal plains.
    • East coastline is very smooth and straight.

    Islands of India

    • There are many islands in Gulf of Mannar, Bay of Bengal and the Arabian sea. The Lakshadweep islands in Arabian sea are small islands and are formed by coral reefs. The Rameswaram island in Gulf of Mannar is also of coral origin.
    • The major groups of islands in Bay of Bengal are Andaman group and Nicobar group. The Andaman and Nicobar islands are mostly of volcanic origin. The Nicobar group of islands lies to the South of Andaman group and are much smaller in extent and number.

      Andaman and Nicobar Islands

      • Andaman and Nicobar Islands are uneven in nature and rugged in terrain. These islands are remnants of submerged mountain range. The submerged mountain range is an extension of Arakan mountains of Myanmar.
      • These islands are almost densely forested. About 90% of the islands are covered with forests. It is an area having low population density.
      • These islands are being influenced by both Northeast and Southwest monsoons.
      • 100 channel passes between Andaman islands and Nicobar islands.
      • India's only active volcano is located on Barren island in Andaman Islands.

      Lakshadweep Islands

      • Lakshadweep islands are having flat topography and they do not have any forests.
      • These islands are influenced by only South-West monsoons.
      • These islands are having high population density.
      • 90 channel passes between Lakshadweep and Minicoy islands.
      • 80 channel passes between Lakshadweep and Maldives islands.

    Coastal plains and islands of India holds extreme importance from strategic as well as economic viewpoint of the country. Most of India's foreign trade is done through the ports that are located at the junction of coastal plains and the seas. Islands increse our sovereignty and jurisdiction over a large areas of territorial waters.