The threat of flash-floods in Himachal Pradesh from a high-altitude lake in China has receded as the alarming accumulation of water in the lake eased with the natural clearing of blockades, a senior official said Thursday.
"The water level had increased alarmingly in the Parechu Lake (in Tibet) last month mainly due to blockades along the main stream channel," Chief Secretary Sudripta Roy told IANS.
"There was a threat that the lake would breach its banks. But now the water outflow has started receding naturally. The threat has subsided," he said.
But the government is constantly monitoring the outflow from the lake through satellite images, the chief secretary said.
The Parechu river, a tributary of the Spiti river, originates in Tibet and joins the Spiti river at Sumdoh, 350 km from here, in Kinnaur district.
The Spiti river is the major tributary of the Satluj river basin. It joins the Satluj at Khab, also in Kinnaur district. The sudden increase in the outflow in the Parechu river posed a grave threat to life and property on the Indian side.
Scientific Officer S.S. Randhawa of the State Council for Science, Technology and Environment said impounding of water in the Parechu Lake was due to huge accumulation of debris.
He said debris had caused partial blockade of the outflow, causing accumulation of the water in the lake depression.
"The water accumulation was first noticed June 22. The blockades were cleared naturally July 5, and the water started discharging normally.
"By July 15, we noticed there was slight change in the water level (in comparison to July 5). The water had again started accumulating in the depression," he said.
"Although accumulated water is there, the outflow now seems to be normal," he added.
Regional Director P. Gyamba Dorje of the Central Water Commission said the water spread of the Parechu river has increased to 100 hectares, from the original 43 hectares.
He said the National Remote Sensing Agency in Hyderabad has been informed about the development, and it has been monitoring the lake on a day-to-day basis.
"Some blockages are still there. The inflow from the lake has exceeded the outflow. But there is no need for panic," Dorje added.
Himachal Pradesh experienced flash floods in 2005, as the Parechu Lake breached its banks.
