Neyyar dam safe: CESS

Thiruvananthapuram: The fracture in the ground reported from an area near the Neyyar dam is the result of soil dislocation, a localised phenomenon that poses no danger to the dam, scientists from the Centre for Earth Science Studies (CESS) reported on Monday.

T. Radhakrishna, Director, CESS, and G. Sankar, scientist, came to the conclusion after visiting the site to study the fracture that had led to concern among the local people. The district administration had shifted two families from the area on Sunday after the crack in the soil started extending.

Rotational slide

Mr. Sankar said the fracture was the result of a rotational slide, a small dislocation confined to the top layer of the soil. “The area between the river and the left bank canal where the fissure had developed is an unstable chunk characterised by reworked soil. Different layers had been added to raise the level of earth here. The heavy rain over the past few days saturated the soil layers, leading to a small dislocation. The cracks seen on the walls of the houses were also caused by the same phenomenon,” he said.

Ruling out the chance of a tremor in the region, the scientists said they had verified seismic data to confirm the fact.

“The small area between the river and the canal is unstable and is prone to another dislocation, especially during rain. There is a possibility that the whole chunk will slip and fall into the river. The residents of these houses are at risk during rain,” Mr. Sankar said.

The scientists said they would submit their report to the Additional District Magistrate on Tuesday.

Earlier in the day, Water Resources Minister N.K. Premachandran visited the area. He had a telephone conversation with the scientists on their analysis.

Source: The Hindu, 30-11-2010

Three Gorges Dam faces a tough test

BEIJING:Seven years ago, the massive Three Gorges Dam was hailed by China's official media as being able “to withstand a once in 10,000 year flood.”

But as China's south was ravaged by floods this week — the worst in a decade — the multi-billion dollar dam's actual capacity to deliver has become a subject of much debate for the media and environmental groups here.

More than 273 people have died in this month's flooding, which has also destroyed 330,000 homes and dislocated tens of thousands of residents. This is the worst flooding in China since the devastating 1998 floods, which claimed 4,150 lives.

On Friday, the water-level of the Three Gorges Dam reached its peak for this year, to 13.86 metres above its reservoir's water-releasing level. The water-level has now risen to 158.86 metres, only 16.17 metres short of its maximum capacity.

The dam's construction, which as of 2008 had cost $26.5 billion and displaced more than one million people, has been justified by the government as an essential solution to the Yangtze river's recurring flooding problems.

The dam faced its toughest test yet since it opened in 2008 on Friday, with peak flows forecast to touch 70,000 cubic metres a second.

With the Yangtze's upper reaches continuing to swell, huge waves of water were released from the dam at 40,000 cubic metres per second, prompting concerns that opening the sluice-gates would cause further damage downstream.

Source:The Hindu 24 July 2010