Islands in the Gulf of Mannar: Part 1

The Laccadive Sea

The Laccadive Sea or Lakshadweep Sea is a body of water that includes the Lakshadweep islands, the Maldives, and Sri Lanka.

Laccadive Sea

The International Hydrographic Organization defines the limits of the Laccadive Sea as follows:

On the West. A line running from Sadashivgad Lt., on west coast of India (14°48′N 74°07′E) to Corah Divh (13°42′N 72°10′E) and thence down the west side of the Lakshadweep and Maldive Archipelagos to the most southerly point of Addu Atoll in the Maldives.

On the South. A line running from Dondra Head in Sri Lanka to the most southerly point of Addu Atoll.

On the East. The southeastern coast of India and west coast of Sri Lanka.

On the Northeast. Adam’s Bridge between India and Sri Lanka.

The Gulf of Mannar and Adam’s Bridge

The Gulf of Mannar is a large shallow bay, a part of the Lakshadweep Sea between the southeastern coast of India and the West coast of Sri Lanka. The estuaries of the river Thamirabarani of south India and the river Aruvi Aru of Sri Lanka drain into the gulf.

Adam’s Bridge separating Gulf of Mannar from Palk Bay

An isthmus composed of limestone shoals, and coral reefs, popularly known as Adam’s Bridge or Ramsethu, lies between Pamban Island, off the southeastern coast of Tamil Nadu, India, and Mannar Island, off the northwestern coast of Sri Lanka.

Aerial view of Mannar Island and Adam’s Bridge.

The bridge is 18 miles (30 km) long. Geological evidence suggests that this bridge formerly connected India and Sri Lanka.

The Rameswaram cyclone of 1964 started with the depression that formed in the South Andaman Sea on December 17, 1964. On December 19, it intensified into a severe cyclonic storm. From December 21, it moved westwards, 400 km to 550 km per day. On December 22, it crossed Vavunia in Sri Lanka with a wind speed of 280 km per hour. On December 22-23 night, the cyclone and moved into Palk Strait and made landfall in Dhanushkodi, India. The devastating tidal waves that were 7 metres high submerged all houses and other structures in Dhanushkodi town. The death toll rose to 1,800.

In the past too, high-intensity cyclones and storms often ravaged the area around Rameswaram in India.

Records from Hindu temples say that Ramsethu was completely above sea level that could be traversed on foot, until a cyclone in 1480 AD submerged it.

A study conducted by the Geological Survey of India indicated that in 1948-49 the southern part of erstwhile Dhanushkodi Township, facing Gulf of Mannar, sank by
almost 5 meters due to vertical tectonic movement of land parallel to the coastline. As a result of this, a stretch of land of about half a kilometre wide and 7 km in length,
along North-South direction, submerged into the sea together with many roads, residential areas, places of worship, etc.

Now, some sandbanks of the Adam’s Bridge are dry, and the sea is very shallow, only 3 feet to 30 feet (1 metre to 10 metres) deep. This geographical feature of the Adam’s Bridge acts as a barrier to heavy vessels that cruise from India’s west coast to India’s east coast, and ships have to take the long circuitous route around Sri Lanka.

The chief seaports on the Gulf of Mannar are Thoothukudi (formerly Tuticorin) in Tamil Nadu, India and Colombo in Sri Lanka. These ports can accommodate deep-draft vessels, but the shallow sea in the Adam’s Bridge region allows only small shallow-draft vessels.

In July 2005, the Indian Government envisaged the Sethusamudram Shipping Canal Project to dredge and scrape out a deep channel to open a direct shipping route for heavy vessels to ply from the southeastern Gulf of Mannar to the northeastern Bay of Bengal and avoid the long trip around Sri Lanka. However, environmentalists have warned that the project could cause grave damage to the sea life of the Gulf of Mannar and the Palk Strait, and thereby affect fisheries in both the southeastern coast of India and the west coast of Sri Lanka.

. Next: Part 2 – The 21 Islands of India →

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