China, Bhutan or deforestation role in Assam flood?

Streamflow or rainfall data shared by China and Bhutan during the Monsoon makes very few in downstream Assam happy.

The growing volume of water and the silt flowing down through the Brahmaputra originating in China and many of its tributaries from Bhutan is blamed for the flood, a problem aggravating almost every year.

“The Centre is blamed for not providing sufficient funds for floods in Assam. We have a sufficient amount of money for relief work but do we have an action plan in hand as yet for a permanent solution? Look at the volume of water that flowed down from China this time too. I am not saying China released excess water but we must keep this factor in mind before blaming the government,” Assam minister Himanta Biswa Sarma told reporters here recently, when flood wreaked havoc, affecting over 58 lakh people in 31 of the state’s 33 districts.

Although flood is an annual problem, the scale of devastation has increased in the past few years - nearly 100 deaths during every flood, economic loss of at least Rs 5,000 crore and loss of 8,000 hectares of landmass due to bank erosion.

This has prompted a call from many here to persuade China to form a joint action plan to tame the Brahmaputra and a similar mechanism for the rivers flowing down the hills of Bhutan causing devastation in western Assam districts.

The Brahmaputra, the world's second-biggest river, originates in the Tibet region of China. The river flows through Arunachal Pradesh and Assam before it drains out into the Bay of Bengal through Bangladesh.

“There are reports that China has constructed several big dams in the upper reaches of the Brahmaputra and so the flow of water is more when excess water is released suddenly. The water level in the Siang (the Brahmaputra is called Siang in Arunachal) suddenly drops during winter,” said a student leader in Arunachal Pradesh.

Panic gripped the frontier state when the water level in the Siang suddenly dropped in October last year. As per the agreements, China and Bhutan provide river flow or rainfall data to India but the two countries lack a joint mechanism to manage the trans-boundary rivers.

Some experts, however, blame the forest cover loss in Assam and Arunachal Pradesh more than the water from China or Bhutan.

“The Brahmaputra basin receives an average annual rainfall of about 1500 mm, whereas the same is barely 400 mm in the Tibet region. Thus, bulk of the flood flows are generated within the watershed areas of India, while the Yarlung Tsangpo mainly conveys the snow melt stream flow mostly from the Himalayan glaciers,” Nayan Sharma, an adjunct professor of IIT-Roorkee, told DH.

“The extensive loss of forest cover in the North-east has significantly reduced the time of concentration of overland rainwater, which caused hike in flood water accumulation in the river system at a faster pace than earlier. The increased silt load in excess of transport capacity of streams gets deposited in river beds, which decreases the flood-carrying capacity,” he said, stressing on massive afforestation and soil conservation programme in the watersheds, construction of multi-purpose storage dams using advanced technology and channel improvement for the braided Brahmaputra and its tributaries.

According to a report of Global Forest Watch, India lost 16,744 sq km of forest cover between 2000 and 2018, of which 12,523 sq km, a whopping 74.7%, was from the North-eastern states.