Last Updated on: April 02, 2022

Flood and erosion scenario in the state of Assam

The Brahmaputra and Barak rivers with their 50 nos. of major tributaries and innumerable sub-tributaries have crises-crossed the plains of both valleys. Floods, bank erosion and drainage congestion are major problems faced by the state during the monsoon season. The flood of this region is a recurring phenomenon, every year several waves of flood cause damage to huge areas in the state. The loss to people in terms of houses, crops and cattle is immense. The figures of loss run into hundreds of cores every year apart from huge damages to roads, bridges, schools, communication systems and other such facilities. This diminishes the wealth of the nation and has adverse effects on the development of the state.

During post-independence period, Assam faced major floods in 1954, 1962, 1972, 1977, 1984, 1988, 1998, 2002 and 2004. Almost every year three to four waves of flood ravage the flood prone areas of Assam. Average annual loss due to flood in Assam is to the tune of Rs. 200.00 Crores and particularly in 1998, the loss suffered was about Rs. 500.00 Crores and during the year 2004 it was about Rs. 771.00 Crores.

Flood damage Trends in the Brahmaputra Valley

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Another major problem being faced by the state of Assam bank erosion by the river Brahmaputra, Barak and its tributaries. Damages caused due to erosion runs into several hundred crores every year. Bank erosion by the rivers has been a serious issue since last six decades as more than 4.27 Lakh Hectares of land was already eroded away by the river Brahmaputra and its tributaries since 1950, which is 7.40 % of area of the state. As assessed, the annual average loss of land is nearly 8000 Ha. The width of river Brahmaputra has increased up to 15.00 Km at some places due to bank erosion. The surveys carried out at different periods reflect an alarming picture regarding widening of river Brahmaputra which is as follows :

Sl No.	Survey Period	Area covered by the river Brahmaputra
1	First survey (1912-28)	3,870 km²
2	Second survey (1963-75)	4,850 km²
3	Third survey (2006 NESAC):	6,080 km²

Breaches of embankment due to bank erosion by the rivers have become a common phenomenon. New areas are being affected by erosion every year. The riverine fertile agricultural lands of the state are reducing due to erosion, which has a very negative impact on the rural economy of the state.

The extent of damage due to bank erosion is alarming in nature which can be seen from the following table ( as assessed by the Revenue Department):

 

Year	Area Eroded (In Ha)	Village effected (In Nos.)	Family effected (In Nos.)	Value of Property (Including Land Loss)
2001	5348	227	7395	377.72
2002	6803	625	17985	2748.34
2003	12589.6	424	18202	9885.83
2004	20724	1245	62258	8337.97
2005	1984.27	274	10531	1534
2006	821.83	44	2832	106.93

Flood and erosion scenario in the Barpeta district:

The River Brahmaputra, one of the largest rivers of the world and its tributaries namely Beki, Manash, Pahumara, Kaldia, Nokhanda, Morachaulkhowa, Bhellengi, Deojaraetc are flowing through the Barpeta district of Assam. Flood and erosion are the major problem caused by these rivers in the district.

The tributaries of River Brahmaputra ,flowing through the Barpeta district, have originated from Bhutan, Due to heavy rainfall occurred in the upper reaches and excess and sudden water released from dams constructed in Bhutan, these tributaries carry a large amount of sediment load , floating debris along with flood water . These sediment loads are deposited on the river bed and changes the morphology of the river and accordingly causes severe problem of flood and erosion at the downstream areas.

The breaches are occurred in the embankment due to overtopping of the flood water and the bank erosion. These beaches result inundation of a huge area of Barpeta and its nearby districts. As a result loss of human life, domestic as well as wild animal, damage to the public and private property, crops have occurred. Besides flood inundation the river Brahmaputra is also causing severe erosion.