The Brahmaputra island whose area fell to 502 sq km before anti-erosion work reversed the trend

Background

Majuli District in Assam has an area of 1245 sq km and includes the main Majuli Island with an area of 522 sq km, a large number of smaller islands, and the Brahmaputra River up to its south bank touching Jorhat and Sibsagar Districts.
The area of the island was 734 sq km in 1914, whereas the minimum area was recorded to be 502 sq km in 2004.
The entire Majuli island is a part of the alluvial flood plains of the Brahmaputra river; the Island is formed of soil consisting mainly of silt deposits, and the soil is without cohesion and thus susceptible to erosion.
The problem of erosion was severe after the disastrous earthquake of 1950, and as per Survey of India topo-sheets and satellite imagery data the island lost 206.7 sqkm from the year 1949 upto the year 2004.
The Brahmaputra Board was requested by the Government of Assam in 1999 to take up necessary measures for protection of the island, and work started in January 2004 in four phases.
Major works included raising and strengthening 96.25 km of embankment with breach closure at 24 locations, construction of five spurs with boulder and geo-bag, numerous RCC porcupine screens and bank revetment.
Erosion in most of the vulnerable locations, except for a length of about 10 km along the Brahmaputra, could be contained through these measures.
The area of Majuli Island increased from 502.21 sq km in 2004 to 524.29 sq km in 2016, a net gain of 22.08 sq km as per study on satellite imageries.
The Brahmaputra is described as one of the most difficult rivers to tackle, as it is very dynamic with morphology changing continuously and carries the highest silt amongst the rivers of its size.