Monsoon threat over quake-hit Siang river

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River experts are warning of lake bursts formed upstream at Yarlung-Tsangpo River after earthquakes hit the region in November.

The burst could result in loss of human lives and flooding of villages in India's northeastern state. A similar incident in April 2000 had killed around 30 and left more than 1,000 families homeless.

Chintan Sheth from India's National Center for Biological Sciences told CGTN Digital that the clock is ticking as the monsoon rains are likely to hit the region in May this year and pre-monsoon showers starting next month.

“The dams can burst at any moment. Cloud cover will furthermore obstruct clear views of the river hampering disaster relief operations,” he said.

River experts and researchers are demanding India and China to work together for the safe release of the water and protect dozens of villages downstream from inundation.

A recent satellite image of barrier lakes shows signs of bursting. /NASA Photo‍

“Bilateral meetings and deployment of operations to safely drain the dams will be a timely call that can prevent loss of lives and property of the people,” Seth added.

The earthquakes triggered landslides blocking the river's stream at various points resulting in the formation of three barrier lakes. The quake also caused massive landslides and polluted the river.

Dr. Jeffrey Kargel, a senior research scientist at the University of Arizona, observed there is still some uncertainty about the volume of the lakes, but the rough estimate of about 19 million cubic meters for just one of the lakes is still enough to make a possible catastrophic lake release.

“Furthermore, the chain of lakes means that one lake draining into the next could create conditions for a very sudden release of water, meaning very high peak discharge.”

The Yarlung Zangbo River in China's Tibet Autonomous Region known as Siang River in India runs through a sensitive seismic zone and a very delicate geographical formation.

The Gyala Peri Mountain lies north of the Siang River and west of the Yigong Tsangpo River. The Yarlung-Tsangpo flows through a gorge at Gyala Peri and the Namcha Barwa Mountain. The Siang then merges with the Yigong Tsangpo and from there takes a complete U-turn.

India continuously faces the threat of transnational floods due to landslides. In 2014, a landslide at Sindupalchowk at India-Nepal border blocked Kosi River for nearly 11 hours causing flood threat in Bihar.

Timely intervention by Nepalese and Indian government averted the flood; Nepalese army released the water through controlled blasts. Researchers are calling for a similar joint action to release the water from barrier lake formed upstream Yarlung-Tsangpo River.

In 2008, earthquakes with a magnitude of 8.0 on the Richter Scale hit Sichuan in China causing hundreds of landslides leading to the creation of barrier lakes. “China has the expertise to release water from these lakes formed by landslides," Chintan added.