World's largest delta fast disappearing into sea
KOLKATA: The world's largest delta, Ganga-Bhagirathi, is slowly
disappearing into the sea, finds a study by river expert Kalyan Rudra.
The study launched on Saturday by union urban development minister
Sougata Roy in Kolkata reveals that the Indian ocean may soon lose the distinction of being home to the world's largest delta, the Ganges delta.
The research titled "Atlas of Changing River Courses in West Bengal", a
project of the Sea Explorers' Institute, was funded by the Union and
the Bengal governments. The project was started by Rudra and his team in
November 2009 and was completed in March, this year.
"The delta
is being swallowed by the sea at an alarming rate both from its apex
and the base," said Rudra. Of the 36 delta regions in the world, the
Ganga delta which empties into the Bay of Bengal has been the biggest one. The Ganga-Bhagirathi delta spans 57,000 square km - known to be the largest delta in the world. While the sea is encroaching inland, swallowing islands
in the Sundarbans and adjoining areas at the bottom of the delta, the
apex (from where the Bhagirathi takes off from the Ganga) is also
shifting southwards.
Rudra said he began the research with the
help of the first map of Bengal, drawn by the first Surveyor General of
India, James Rennel, in 1767, as the reference. This was complemented by
maps drawn by J B Tasin in 1841, the revenue map of 1855, survey of
India's map of 1917, US Army map of 1955, and satellite images over the
past 30 years, the last one being the satellite image of 2010 sent by
Landsat.
Rudra said, "A map drawn in the 1650s clearly indicates
that the Bhagirathi separated from the Ganges at a place near Rajmahal
in Jharkhand. Rennel's 1767 map shows that the split occurred at Suti in
the south. In a 1931 map, the location had further shifted to Giria in
West Bengal.
The latest satellite imagery shows that the river now takes off from
Mithipur, a place near Jalangi in Murshidabad, which is around 120 km
from Rajmahal."
The research titled "Atlas of Changing River Courses in West Bengal", a project of the Sea Explorers' Institute, was funded by the Union and the Bengal governments. The project was started by Rudra and his team in November 2009 and was completed in March, this year.
"The delta is being swallowed by the sea at an alarming rate both from its apex and the base," said Rudra. Of the 36 delta regions in the world, the Ganga delta which empties into the Bay of Bengal has been the biggest one. The Ganga-Bhagirathi delta spans 57,000 square km - known to be the largest delta in the world. While the sea is encroaching inland, swallowing islands in the Sundarbans and adjoining areas at the bottom of the delta, the apex (from where the Bhagirathi takes off from the Ganga) is also shifting southwards.
Rudra said he began the research with the help of the first map of Bengal, drawn by the first Surveyor General of India, James Rennel, in 1767, as the reference. This was complemented by maps drawn by J B Tasin in 1841, the revenue map of 1855, survey of India's map of 1917, US Army map of 1955, and satellite images over the past 30 years, the last one being the satellite image of 2010 sent by Landsat.
Rudra said, "A map drawn in the 1650s clearly indicates that the Bhagirathi separated from the Ganges at a place near Rajmahal in Jharkhand. Rennel's 1767 map shows that the split occurred at Suti in the south. In a 1931 map, the location had further shifted to Giria in West Bengal. The latest satellite imagery shows that the river now takes off from Mithipur, a place near Jalangi in Murshidabad, which is around 120 km from Rajmahal."
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