Under Threat

PROBLEM OF EROSION and FLOOD INNUNDATION

This island is facing imminent extinction from two most serious problems:-

• Gradual Loss of land area due to severe bank erosion.

• Flood inundation

Reducing Land Mass

Majuli Island prior to 1950 earthquake had an surface area of approximately 1250 sq.km. However, after the great earthquake, erosion of the river Brahmaputra in this reach became active and a part of the southeast and southwest side of the island was washed away by the river. This has posed an increasing threat to the island and the rich natural and cultural heritage it represents. This has affected the bio-diversity of the island, flora and fauna, socio cultural fabric and the demographic pattern of the population. One third of the Satras of the island had to be shifted to the north and south bank of the Brahmaputra This naturally affected the cultural heritage of the island

With the passage of time, modern lifestyle is also affecting particularly the physical side of the culture such as use of modern building materials, costumes of dances and drama, etc. However, the basic concept of the cultural heritage the Satras represent has not been influenced by time and circumstances. The Satras have been largely successful in retaining the original flavour, composition style and content as propounded by the founder of these unique heritage.

It may clearly be mentioned that no such cultural heritage intermixed with the natural heritage of the place is ever found anywhere in the world as to the comparison with Majuli’s heritage.

BANK EROSION DUE TO THE BRAHMAPUTRA

The main factors may, be attributed to the excessive sediment charge and its age-old tendency to shift on either side. Excessive sediment load is mainly due to the frequent seismic disturbances of low magnitudes and earthquake of disastrous nature in combination with the deforestation in upper catchment area of the river basins. It is apprehended that the great earthquake of 1950 has also caused severe erosion of bank of the rivers around the island as the Brahmaputra is traversing nearly 90 Km along the southern side of it from Tekeliphuta to downstream. The losses of dykes at Tekeliphuta, Haldhibari, Salmora, Bessamora, Burakalita and complete disintegration of Ahatguri Mouza (Tehsil) in the extreme western end is the result of bank erosion.

In a braided river like the Brahmaputra, short time channel migration is quite drastic. The rate of rise and fall, the lumber and the position of major active channel during floods, the formation and movement of large bed form, cohesion and composition of bank materials alongwith intensity of bank slumping are main factors governing the movement of bank line. It is observed that modification of bank line movement takes place during falling stage when excess sediment deposited as bars within the channel causing change of flow direction and migration of sand –chors (small islands) there upon.

Due to the gravity and magnitude of the problem, no bank protection work to prevent the progress of erosion has yet been tried here. Therefore where there is breach of embankment due to erosion, a retirement is provided.

BANK EROSION DUE TO THE RIVER SUBANSIRI

Like other rivers flowing from the lower range of Himalayas, on the North bank of Brahmaputra and owing to existence in seismic zone the Subansiri also carries enormous silts in flood seasons and thereby has lost her stability in plains. The gradient of the riverbed in the gorge and boulder reach is very steep and in the plains it is much flatter. Enormous silt with high velocity gets deposited in the bed of the river itself in the plains causing aggravation and the river becomes braided resulting bank erosion. Formation of sandbars within the river also helps the bank erosion. The great earthquake of 1950 had also caused change of course of the river alongwith shallowing the river.

The dyke from Baghgaon to Ghuriagaon of the length of 9 (Nine) Km existed in lower Majuli was eroded away both by the Brahmaputra in the South and the Subansiri on the north. As such the lower reach of the island is in the process of extinction due to erosion.

PRESENT EROSION/FLOOD PROBLEM:

The braided river Brahmaputra had developed a channel at down stream of Bessamora at Dakhinpat, namely Chumaimari channel, flowing along the southern side of the Brahmaputra dyke from Bessamora to Dakhinpat and than to Kamalabari. The channel, in the beginning, was very in significant but now it carries much more flood water with high velocity causing erosion of banks and thus caused the loss of the Brahmaputra dyke from Dakhinpat to Kamalabari at 5th Km in Aug’93. Now the width of the breach opening is nearly 2.00 km and the channel shifted towards Tuni rivulet and joined the latter on 14.8.94 at Nam Sonowal village. The breach opening has caused flooding of the area lying around Kamalabari Township and Kamalabari satra including bank erosion near the Kamalabari police station at its receding stage. Erosion of bank by the channel was also observed at 4th to 5th km of Tuni R/B embankment from Kamalabari to Burakalita and in the extremity of the island due to the Brahmaputra. Erosion of bank upstream of Dakhinpat and at Bessamora has been also noticed during the flood season of 1994. Further erosion of bank at Jengraimukh by Kherkotia Suti from the floods of Champara etc. has also been noticed during the flood season of 1993 and 1994.

The breach occurred in the dyke from Dakhinpat to Kamalabari extended to 2.5 km during the flood of 1995 and inundated a large area of the Kamalabari area and the gushing water extend into the Tuni River threatening the Kamalabari Satra and the town.

From past history also, it is, understood that Majuli island was subjected to the floods of the rivers on either side in high spate.

The following extracts from "A History of Assam", E.A. Gait shall corroborate this expression.

"In 1570 AD there was a flood which destroyed the crops and caused something like a famine. There was a heavy flood in 1642, many heads of cattle were washed away. Several earthquakes occurred in the same year. It has already been stated that the great flood of 1755 is responsible for change of course of the Brahmaputra."

In the recent years there were floods in the Brahmaputra in 1931, 1935, 1948, 1949, 1951, 1962, 1962, 1966, 1969, 1970, 1977, 1987, 1988, 1991 and 1996.

After 1950 earthquake, spilling of the Brahmaputra in the upper reaches of the island started in large scale and thus immediate measures had to be taken to contain the spilling by way of constructing embankment system. But the dyke systems have failed to block the fury of the legendary only male river in the world.

In 1998, the floodwaters submerged almost the entire island. Even the Satras, which are normally built on earthen embankments, were under 6-7 feet deep water. The Flood wiped out entire standing crops and rendered thousands of acres sterile depositing millions of tonnes of sand.