Sikkim has introduced three key engineering projects aimed at mitigating the risks posed by Glacial Lake Outburst Floods (GLOFs). These initiatives include the installation of solar-powered pumping systems at Shako Chho, the construction of a flood-retention structure at Dolma Sampa in the Lhonak Valley, and the establishment of a safety wall at the outlet of the Gurudongmar lake complex. These measures are designed to enhance safety and reduce the potential impact of flooding in the region.
Its terminal moraine is high but permeable, and the lake has no natural outlet. The National Disaster Management Authority (NDMA) has advised against directly disturbing the fragile moraine. A Detailed Project Report (DPR) has been prepared and submitted through the state disaster management authorities, with the proposal being examined at the Government of India level. The second proposal concerns the Lhonak Complex, comprising South Lhonak, North Lhonak and Changsang lakes. The third proposal is for the Gurudongmar Lake complex, which comprises three lakes. the other two are considerably larger While one lake is accessible to tourists and pilgrims. The complex has also expanded significantly over the past three decades.
The proposal therefore envisages initially pumping out around 8 million cubic metres of water using eight solar-powered pumps, with the possibility of lowering the lake level by about 20-40 metres. Because there is no electricity supply at the site and transporting fuel to such a high altitude would be difficult, conventional pumping is considered impractical. At Shako Chho, located at around 17,000 feet and about 12 km from Thangu on the route to Gurudongmar, the proposal is to lower the lake level through solar-powered pumping. The lake is estimated to hold around 27 million cubic metres of water. Instead of carrying out an intervention directly at the lakes, Sikkim is studying a retention structure at Dolma Sampa, around 24 km downstream near Muguthang, where the valley widens naturally.
