In pictures: Six Hydropower projects wrecked by flash floods in Uttarakhand

A portion of the Nanda Devi glacier broke off in Uttarakhand's Chamoli district on Sunday, triggering an avalanche and a deluge in the Alaknanda river system. The disster washed away hydroelectric stations, leaving at least 14 people dead, and over 150 missing. Local reports suggested workers of the NTPC-owned Tapovan Vishnugad hydropower plant were stuck in it owing to the flash flood. Sixteen of them have since been rescued, but about 125 were still missing.

The sudden flood in the middle of the day in the Dhauli Ganga, Rishi Ganga and Alaknanda rivers -- all intricately linked tributaries of the Ganga -- triggered widespread panic and large-scale devastation in the high mountain areas. The privately owned Rishi Ganga power project (130 Mw), which is on the upper stream of the Alaknanda river, was the first to face the brunt of the avalanche. The debris from this plant caused damage to other units downstream.

As night fell in the ecologically fragile Himalayas and rescue work in the difficult-to-access areas became more harder still, there were fears many may be dead. Apart from Tapovan (520 Mw), Pipal Koti (4x111 Mw), the hydro project of state-owned THDC, also suffered damage.

Vishnuprayag (400 Mw) of Jaypee Group suffered damage as well. Experts have called for extreme caution now when awarding infrastructure projects in the area.

In June 2013, heavy rain, coupled with flash floods in several areas in Uttarakhand, killed over 5,000 people and destroyed villages, livestock and dams. There was massive debris accumulation, electrical equipment replacement and loss of total generation capacity for more than six months.

Unprecedented flash floods in June 2013 in Uttarakhand completely submerged the power house, and caused accumulation of a great deal of muck and debris in the dam reservoir. Besides disrupting a river's natural flow, such projects are viewed as the biggest threat to its ecosystem and the biodiversity in its basin