Sikkim flash floods: Loss to hydroelectric projects on river Teesta yet to be calculated

While the actual damages will be assessed only after the water level recedes to normal and the approach roads are restored, scary visuals emerging from Sikkim reveal immense destruction to the hydroelectric projects in the state. The now-damaged Teesta-3 dam was completed at a cost of over Rs 14,000 crore.

The Teesta-6 hydroelectric project in the Sirwani village is aimed to generate 2,400 MUs in a 90% dependable year with an installed capacity of 500 MW. With an investment proposal for an estimated cost of Rs 5,748 crore, the implementation of the project by NHPC was approved by the CCEA on March 7, 2019. The project was scheduled to be completed in 60 months.

Several environmental activists have repeatedly objected to the construction of multiple run-of-the-river projects over the Teesta, which traverses most of its length in mountainous or hilly terrain in India before it enters Bangladesh. The Lhonak Lake, which led to the origin of the current floods, has been described by NHPC as one of the fastest expanding lakes in the Sikkim Himalayan region and one of the 14 potentially dangerous lakes susceptible to Glacial lake outburst floods (GLOFs). The United Nations has been working on GLOF mitigation in the region with several scientific studies already conducted on the issue.

Anand Sankar, a former journalist who has extensively reported on hydroelectric projects, termed the turn of events as a multi-government failure, as the Teesta-3 project conceptualised in the 1990s was constructed till 2016 and multiple governments ignored warnings by environmentalists.

Fourteen bodies have been found so far while 102 people, including 22 Army personnel, remained missing after a cloudburst over Lhonak Lake in North Sikkim triggered a flash flood in the Teesta river basin.

So far, 2,011 people have been rescued, while the calamity affected 22,034 people, the Sikkim State Disaster Management Authority (SSDMA) said in its latest bulletin.

The flash flood in the Teesta river, triggered by the cloudburst in Lhonak Lake in North Sikkim, caused accumulation of huge quantity of water, which turned towards Chungthang dam destroying the power infrastructure before moving downstream in spate, flooding towns and villages.

The flood destroyed 11 bridges in the state, with eight bridges getting washed away in Mangan district alone. Two bridges were destroyed in Namchi and one in Gangtok. Chungthang town bore the maximum brunt of the flood with 80% of it getting severely affected. The NH-10, considered the lifeline of the state, sustained extensive damage at several places.