The Central Water Commission has decided to review the design of dams vulnerable to glacial lake outburst floods (GLOFs) following the collapse of the Sikkim Urja Teesta-Stage III dam owing to a breach in the South Lhonak Lake in October last year.

The 1,200MW dam was washed away by the Teesta floodwaters, killing over 100 people and causing widespread damage.

In a post-disaster assessment report submitted by Sikkim chief minister Prem Singh Tamang (Golay), it was estimated that ₹3,673.25 crore would be needed for recovery and reconstruction.

Union minister of state for Jal Shakti Raj Bhushan Choudhary has said a review was underway “to ensure their (dams) adequate spillway capacity for a combination of probable maximum flood/standard probable flood and GLOF”.

“Further, GLOF studies have been made mandatory for all new dams planned having glacial lakes in their catchments,” Choudhary informed the Lok Sabha recently.

According to government reports, 47 dams — 38 commissioned and nine under construction — have been identified by the Central Electricity Authority under the power ministry as vulnerable to GLOFs.

The CWC monitors 902 glacial lakes and water bodies, including over 400 glacial lakes, every year.