Guwahati: A preliminary report by the National Dam Safety Authority (NDSA) on the “flash flood in Teesta basin” in Sikkim has revealed that dam authorities lost valuable time in taking preparatory measures after being alerted by the Indo-Tibetan Border Police (ITBP) about the rising water level in the river, The Print reported.
On the intervening night of October 3-4 this year, the South Lhonak glacial lake in north Sikkim breached its banks, triggering devastating floods that claimed 89 lives and caused widespread damage to infrastructure, including road networks, bridges, and three major hydropower projects.
The flash flood swept away the Chungthang dam and damaged the spillways of the Dikchu dam.
Sources in the Sikkim and central governments have disclosed that the NDSA’s preliminary report indicates that between the time the ITBP informed the dam authorities about the rising water in the Teesta river and the deluge reached Chungthang town, the dam authorities had sufficient time to take measures like emptying or at least reducing water in the dam’s reservoir.
The NDSA has stated in its report that instead of acting on the ITBP’s communication, the dam authorities wasted crucial time in confirming the news.
“By the time the water actually reached Chungthang dam, it was too late to do anything. A team of dam staff had at the last moment gone to open the gates but was swept away,” a central government source who wished to remain anonymous told ThePrint.
A Sikkim government official, also seeking anonymity, said the reservoir of the Chungthang dam was full as the Teesta Stage-III hydropower plant was being operated at 10-15 percent over capacity. The reservoir, the official added, was holding approximately 5 million cubic meters of water, the news website reported.
The NDSA shared the preliminary report with the Union Jal Shakti ministry, the Sikkim government, State Dam Safety Organizations of Sikkim and West Bengal, and the Union power ministry in mid-October. A final report is expected in three months’ time.