Erosion and its Dynamics in Majuli

Soils of Majuli belong to alluvial type formed due to fluvial actions of the river Brahmaputra. The alluvial soils consisting of both younger alluvium and old alluvium are found to occur in the island. It is mostly composed of sandy to silky loams and close to the riverbank it is less acidic being sometimes neutral. The fringe areas of the island, which are under active fluvial sedimentation, represent the new or young alluvial soils. New alluvial soils of the island are most suitable for growing oil seeds, pulses and winter (rabi) crops. The agrarian economy of Majuli thrives mainly on the fertile croplands of old alluvium. Flood and its allied problem of erosion are the two most gruesome problems of Majuli.

It is important to note that Majuli is not a sandbar and sandbar formation processes are no way associated with the origin of the Majuli Island. Unlike the numerous bars and islands formed within the Brahmaputra channel, Majuli has its own history of genesis. Majuli was formed as a result of the southward migration of the Brahmaputra. Since early times, southward migration of the Brahmaputra has been an important fluvial geomorphic process. Being an Integral part of the active fluvio geomorphic regime of the Brahmaputra flood plain, Majuli has been experiencing severe floods from early days. The frequent fury of floods in Majuli may be well attributed to the topographical changes of the Brahmaputra and its tributaries caused by the great earthquakes of 1897 and 1950. Of these two quakes, the 1950 earthquake mostly affecting the upper Brahmaputra Valley including Majuli was the most severe one causing tremendous changes or the riverine topography and sudden rise or river bed. The aggressive nature of floods in Majuli thus made a quantum leap especially after the great 1950 earthquake. Because of its peculiar location amidst the active floodplain of the Brahmaputra, Majuli gets inundated not only in severe floods but also in normal floods. The resent flood occurrence scenario in the island reveals that the nature of flooding, frequency of their occurrence and the magnitudes of flood damages have been changing and increasing over the years. Besides floods, severe bank erosion of the Brahmaputra is causing havoc to the island eroding large areas. A temporal study of the erosion scenario of Majuli reveals that in 1915 the island occupies an area of 1245.59 sq. km and in 1971 after a period of 57 years its area was reduced to 924.6 sq. km accounting for an erosional rate of 5.63 sq. km/year. The area of the island was further reduced to 645 sq. km in 1995, thereby maintaining an average rate of erosion in the order of 7.4 sq. km/year. Formation of the sand bass of permanent type also forming alongside this erosion, thus heaping the Net landmass at 1100 sqkm as of present date. In view of the growing dimensionality of the flood and erosion problems of Majuli, it is pertinent to take appropriate steps to save this world famous centre of Vaishanavite culture, which has recently fallen prey to severe floods and bank erosion posing threats to its very existence.