| A bird’s-eye view of the Nathpa Jhakri hydro-electric project that is under threat of being swamped. (PTI)
New Delhi, Aug. 12: A mystery dam in Tibet that has been ticking away, threatening to burst and flood Himachal Pradesh, was said to be overflowing today, 12 days after a landslide blocked the Pare Chu river in its course.
Technical sources in India’s ministry of water resources said the reason for the overflow could be as simple as the rising level of the lake behind the dam or as complex as an explosion.
Indian technical hands had indeed asked, after China had warned of the impending disaster, if controlled explosions to ease the pressure on the dam were possible. But they had been told that the topography of the region would not permit such a measure.
“At the moment we can confirm that there is no breach in the dam but the trickle over it has turned into an overflow. The ‘dam’ is intact but it is unstable,” a water resource ministry official said after a meeting of the crisis management group.
“Almost all information is interpreted from satellite photographs because the terrain is difficult and nearly inaccessible. We are trying our best to ascertain the quantum of water in the lake.”
The last estimate was 49 million cubic metres but that has increased. The depth is estimated to be 35 metres.
A Central Water Commission assessment for crisis managers has said that a 30-foot-high wave could swamp through the Sutlej in lower Himachal, even some 250 km away from the India-Tibet border. Such a wave would take about four hours at 10,000 cusecs per second to reach the hydel power project at Nathpa Jhakri.
China’s record of mega projects that hamper the environment in Tibet is suspect because of similar disasters in the past. The Pare Chu is the only river whose source is in India, in the Parang La height in Spiti, and which flows into Tibet’s Ali Prefecture, takes an almost 90-degree turn before flowing into Spiti and Kinnaur in Himachal again.
In Delhi, foreign ministry spokesperson Navtej Sarna said Beijing had informed Delhi that water was overflowing. “They pointed to the instability of the artificial dam and the potentially serious situation that prevails,” Sarna said.
On reports that there has been an explosion at the dam, he said there was no confirmation “either way”.
“A chain of wireless sets has been set up in villages to be used to pass on warnings on rising water levels. All villages have been sensitised in advance. They have been informed about safe places they can evacuate to in the event of flash floods,” Sarna said. An Indo-Tibetan Border Police post has also been set up at the point where the Pare Chu enters Indian territory, he added.
In August 2000, a surge flood in the Pare Chu had taken a toll of 100 people in Kinnaur alone and had washed away more than 90 bridges and strategic roads in Himachal. Even that year there were reports of explosions on a landslide-created dam. The difference this time is that the Chinese authorities have alerted India to the possibility of a surge flood.
Last year, the Beijing Review magazine quoted the commissioner of Ali Prefecture as saying that “worsening natural conditions, atrocious climate and desertification” were taking a heavy toll of the terrain. Adding to the consternation is an earthquake measuring 5.6 on the Richter scale that was felt in Ludian County in southwest China, and heavy rainfall and landslides in Ali Prefecture.
Defence sources said Indian Air Force helicopters have been put on standby to evacuate people. Defence personnel and administrative agencies went through a drill on Sunday on how to respond in the event of the flash flood.