The ravages of flood

The ravages of flood

/ Guest Column / Monday, 13 July 2020 16:30

By Kamal Baruah

Over the centuries people have learnt to live with rivers. The catastrophic floodsof river killed people from the remotest ages. There were incidents of man-made flood from the Huayuankou event in 1938 when China used flood to protect from the invasion of Japanese that killed a million of Chinese citizen and Japanese soldiers from catastrophic floods. Thereby Huang-he was China’s sorrow. In 1955, China has successfully controlled the Huang-he by building overflow channels and increasingly taller dikes from its ambitious 50-year construction plan and flood-control program. This included extensive dike construction, repair and reinforcement, reforestation and the construction of a series of dams to control the river’s flow, produce electricity and supply water for irrigation. 

Like the yellow river, the Brahmaputra has been Assam’s sorrow. The river has another terrifying story of annual flooding that eats away the entire economy of Assam. The 2,900 km-long trans-boundary river originates as the Yarlung Tsangpo from the Manasarovar, the highest body of freshwater lake in the world. It is fed by the Kailash Glaciers near Mount Kailash in Tibet. Besides Brahmaputra, it’s the sources of great rivers namely the Ghaghara (tributary of Gangas), Sindhu and Sutlej (tributaries of Indus).

It flows 2,840 km in Tibet with tributaries Nyangchu, Lhasa, Nyang and Parlung. In Arunachal it’s called the Siang, finally appears as Dihangin plains and gathered the tributaries Dibang and Lohit, it becomes the Brahmaputra in Assam. The rain fed Brahmaputra gathers the bulk of its volume from its tributaries from Arunachal (Subansiri, Kameng), Assam (Ranga Nadi, Jia Bhareli, Puthimari, Bhutan (Manas, Gangadhar), Patkai Hills of Myanmar (BuriDihing), Nagaland(Dhansiri), Meghalaya(Kopili) and Sikkim(Teesta).In Bangladesh, it’s Jamuna from the Ganges (Padma in Bangladesh) and Meghna and forming the world’s largest delta into the Bay of Bengal.

Understanding the Brahmaputra has yet to be resolved. Ancient Assam witnessed flood only in the north bank of river Brahmaputra. After the great earthquake 1950, innumerable timber logs clogged the river, carried sulphurous material and fish died. The river beds raised as sediments blocked causing tremendous changes of riverine topography. As landslides blocked rivers in the mountain, the channels shifted and erosion took place. The river shifted laterally from Pasighat to Goalpara. And flood started occurring every year for both the banks. Being brought up in a riverine village since childhood, we saw the flood levels going high every year which might be the cause of sand-banks impeded at the mouth of stream.

Brahmaputra isn’t just a river, it’s a huge sea. It has vastness of water landscape amazingly 15 km wide. Assam flood is singularly different in terms of duration and magnitude of erosion. It can’t be controlled merely by strengthening embankment and anti-erosion measures. Let Brahmaputra flows, people have to live with water and explore new avenues. Besides sorrows they can raise the economic potential by growing crops in water. Mr SM Huq, a former Chairman of Central Water Commission quoted above while visiting Palasbari in late 60s.

The woes continue as the river is part of their lives while huge water swept away their village. There are no embankments to protect them. Villagers learnt to live in their stride even it wreaked havoc to their crops. The river people are always under threat. The nature of flood in Assam takes a quantum leap every year. It killed hundreds of human lives (40 this year)and threatened endangered species. Rhinoceros flee to Karbi Hills for high ground. Onlookers see herds of elephants blocking the National Highway. Helpless deer wanders for safety. Floods damage their total kharif crops. The rural economy has gone negative. The Brahmaputra has age-old tendency towards southward shifting its channels and traverse its valleythat emerged Majuli as a riverine island during first half of the 18th century.

Breaches of embankment due to bank erosion have become a common phenomenon. The heavy silt charge and flash floods of north bank tributaries are pushing the bank of the Brahmaputra southward.  Lakhs of Hectares of land was eroded away by the river and its tributaries. Highly erosion-prone landmass Majuli thereby got reduced to half from its origin. The new channels have deteriorated in lower Assam. Palasbari town experienced the threat of severe bank erosion in 1954 that merged into the river. Two thirds of Dibrugarh town has merged into the river.

Assam is geographically situated in the foothills. The tributaries of the surroundings hills carry huge water to plain and large quantity of sediments to its beds. The Brahmaputra can’t contain excessive rain water and it’s seen dangerous for erosion and channel shifting.  With the onset of monsoon, flood woe begins and devastation reminded every year. It remained unresolved and survival of people is under threat.

Dredging of Brahmaputra was undertaken during 1975. The task was unconvincing since sediments get deposited very fast. The traditional sand embankment can’t protect Assam. The cost of such undertaking would be enormous but it has significance for the loss of human life, damage to property, destruction of crops, loss of livestock and deterioration of waterborne health diseases.

When flood recede its bank, the silt / sediment carry by the river remains that fertilise the soil and create arable land. It brings changes to pond and fisheries. Could flooding turn a harbinger of life to its farmers? There is no way to stop this abundant water. Let water spills over the plains. Rather they follow what their forefather practiced. They live by the river.


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