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Mitigating riverbank erosion, a major challenge for Assam government

Many riverine districts in the state continue to be affected by riverbank erosion every year, and the erosion has affected many farmers forcing them to migrate to other parts for survival. Mitigating riverbank erosion is a significant challenge for the Assam government, but this needs a comprehensive strategy, which the state is yet to formulate, writes Rajeev Bhattacharyya.

By Rajeev Bhattacharyya
New Update

Riverbank erosion

In a stinging indictment of the government's failure to check the disaster that has already washed away lakhs of hectares of land over the past several decades, a Parliamentary panel has expressed "concern" over the continuing riverbank erosion in Assam. 

The Committee noted that erosion in Assam was a "big perennial problem" that has caused "significant economic loss besides displacement of the population". It has made a case for erosion to be included in the admissible list of calamities for availing assistance under the National Disaster Response Fund (NDRF) and State Disaster Response Fund (SDRF). 

The report, which was submitted by the Standing Committee on Water Resources to Parliament, also examined the replies by the government on flood, erosion and cooperation with neighbouring countries on rivers. The Committee deliberated in detail on the situation in Assam and other flood-prone states of the country.

In Assam, more than 4.27 lakh hectares of land was already eroded by the river Brahmaputra and its tributaries since 1950, which is 7.40 per cent of the state's total area. According to a government estimate, the annual average loss of land is nearly 8000 hectares. Over the years, as many as 2500 villages have been wiped out, impacting around 4 lakh people across the state, many of whom continue to live on the embankments. Consequently, the width of the Brahmaputra river has increased up to 15 kilometres at some places due to erosion which has gradually increased over the years. A survey carried out between 1912-28 revealed that the area covered by the river was 3870 sq km which expanded to 6080 sq km in 2006.

riverbank erosion Erosion by Aye river last year at Bongaigaon, which is a tributary of the Brahmaputra | Picture courtesy: Special arrangement

The Brahmaputra river is characterised by high mean annual water discharge, high sediment yield and seasonal variability. It is a braided channel with the presence of numerous mid-channel bars and islands called 'Chars', with most of them being temporary in nature that gets submerged during the monsoon. The estimated annual sediment yield of the river is 735 million metric tons of suspended sediment loads which are among the highest for all rivers in the world. 

A common phenomenon has been the breach of embankments due to erosion by the river and its tributaries in Assam almost every year and the shrinkage of fertile agricultural lands in the state, resulting in an adverse impact on the rural economy of the state.

In 2010, experts pointed out that both short and long-term measures to tackle the erosion problem had been executed only on a piecemeal basis during emergency situations depending upon the availability of funds. They have recommended a phase-wise solution for mitigating erosion through a combination of measures, including strategic dredging and protection of erodible bank materials with anchored bulkhead or tie-back sheet piles, spurs, toe and bank revetments.

Riverbank erosion Erosion of embankment at Dhemaji | Picture courtesy: Special arrangement

Government Reply To Parliamentary Panel

The Ministry of Jal Shakti, in its action taken note on the report by the Parliamentary Committee, said the 15th Finance Commission, in its final report, had considered the request of the state governments for the inclusion of various calamities, including river and coastal erosion in the list of notified disasters. 

The ministry explained that "The report concluded that the list of notified disasters eligible for funding from State Disaster Risk Management Fund (SDRMF) and National Disaster Risk Management Fund (NDRMF) fulfilled the concerns of the states and thus did not find merit in further expanding its scope. However, the Commission has further stated that the calamities like the river and coastal erosion can be tackled efficiently through mitigation efforts for which allocation under the mitigation funds have been made." 

riverbank erosion Erosion by Brahmaputra river at Mayong | Picture courtesy: Rajeev Bhattacharyya

Further, the ministry added that for Assam, multiple schemes were being executed by the government's different wings, including projects by the Brahmaputra Board. However, the Committee was 'not satisfied with the replies from the ministry as it felt that no efforts were made to tackle soil erosion considered "grave", particularly in Assam due to recurring floods. 

The ministry informed that the 15th Finance Commission did not find merit in expanding the scope of the list of notified disasters to include calamities like the river and coastal erosion for funding from SDRMF and NDRMF, as these can be tackled efficiently through the schemes for which allocation under the mitigation funds have been made.

The Committee noted that the ministry furnished no information about the quantum of funds allocated and expenditure incurred on the prevention of soil erosion. In view of the fact that erosion has caused major human and economic disasters with a long-term impact on the economy of the region and its people, the Committee reiterated its recommendation "to make endeavours to draw the attention of the Government and persuade it to include soil river erosion in the admissible list of disasters/calamities". The Committee also urged the ministry to take requisite steps to protect the riverine island of Majuli in Assam by strengthening and improving the peripheral embankment system.

Majuli's Precarious Condition

Majuli, located about 260 km east of the state capital Guwahati, is considered the largest inhabited riverine island in the world and the cradle of the Vaishnavite culture of Assam. In 2013, the government included the island in the tentative list of UNESCO's World Heritage Sites. However, large chunks of land continue to be gobbled by the Brahmaputra river every year.

In 2017, the government informed the Lok Sabha that the area of the river island was 733.79 sq km as per the Survey of India in 1940, which decreased to about 502.21 sq km in 2004. At the same time, there was a net gain of 22.08 sq km of land between 2004-16 due to the deposition of silt, which resulted in the increase in the landmass of the river island to 524.29 sq km. 

Many riverine districts in the state continue to be affected by riverbank erosion every year, and the erosion has affected many farmers forcing them to migrate to other parts for survival. Mitigating riverbank erosion is a significant challenge for the Assam government, but this needs a comprehensive strategy, which the state is yet to formulate. 


Rajeev Bhattacharya is a senior journalist in Assam in India’s northeast. He has worked with The Telegraph, The Indian Express, The Times of India and Times Now, and was the managing editor of Seven Sisters Post. He is a Chevening Fellow and author of “Rendezvous With Rebels: Journey to Meet India’s Most Wanted Men” and “Lens & The Guerrilla: Insurgency in India’s Northeast.” He reports on India’s northeast and its border regions with Myanmar, Bhutan, China and Bangladesh.