Majuli is the largest fresh water mid-river deltaic island in the world. The newest entrant in the Guinness Book of World Records this month, this island is situated in the upper reaches of the river Brahmaputra in Assam with mean height of 84.5 m above mean sea level. Covering an area of around 880 sq km Majuli suffers heavy erosion and in the last 30-40 years has been estimated to have lost around one third of its area. Home to around 168,000 people, as per the 2011 Census, the major tribes living here are the Misings, Deoris, Kacharis, who, in turn, are further divided into many sub-tribes. Of these, the Mising are the largest group inhabiting Majuli for centuries.
How was Majuli formed?
Modern scientists have concluded that Majuli was formed due to the hydro-geo-tectonic forces and composed entirely of sediments carried along by a number of tributaries of Brahmaputra as it emerged from the Himalayan tracts of Tibet and gushed down to to the confluence on the southern fringe of Bangladesh. The land formation of Majuli is unique in both lateral and vertical composition due to its process of evolution. While absorbing a series of natural disasters, particularly the great earthquake of 1950 that wreaked havoc on the island, Majuli has been ceaselessly struggling against all odds, with remarkable success, to retain its size and shape for most part of its history, notwithstanding its contours being shaped and reshaped from time to time.
Geography of Majuli: –
According to the census of 1971, the geographical area of the island (including some Chars or Chapori area) was 924.60 sq km; but area of the island, as per record of Revenue, was 1246 sq km in 1993. Subsequently the Brahmaputra Board quoted that due to erosion, the area of the island was reduced to 880 sq km. On Sep 1, 2016, the Majuli island displaced Marajo of Brazil to become the world’s largest river island according to Guinness World Records.
Why the threat?
Several studies have indicated that the Brahmaputra River changed its course abnormally after the Great Assam Earthquake of 1950 of magnitude 8.6. There was a balance between sediment supply and transport and this balance was disrupted by the great earthquake which produced severe landslides, and suddenly provided a large quantum of additional sediment. Descending into the plains, the extra sediment choked the river gradually and initiated bank erosion causing channel-widening. Moreover, there has been a gradual increase in channel slope since 1920. The riverbed of Brahmaputra has also shoaled following heavy siltation due to the construction of flood embankments, deforestation, etc. Many other towns besides Majuli, on the banks of the Brahmaputra River, are also under threat due to abnormal changes in the river course.
Brahmaputra Board prepared the Master Plan of Majuli Island in the year 2000 wherein recommendation was made for over all water resources development in the Island including protection of the Island from flood and erosion. Based on the recommendations, a detailed project report for protection of Majuli Island from flood and erosion was prepared in August, 2000 which was techno-economically cleared in August, 2003. On request of the Government of Assam, Ministry of Water Resources, Government of India assigned ‘Protection of Majuli Island from floods and river bank erosion’ to Brahmaputra Board. Brahmaputra Board took up protection works of Majuli Island in January 2004. Till 2016, about 183 crores have been spent in the protection of Majuli. Broadly, protection works encompass raising and strengthening of embankment, plugging of breaches, casting and laying of permeable RCC porcupine screens, spurs and dampeners, construction of boulder spurs, river bank revetment and construction of raised platforms.