Why in News
The chungthang dam in Sikkim collapse and vanished strategic power plants connected with Bhutan.
The devastation has refreshed worries over two of three Indian-assisted, under-construction mega hydropower projects in Bhutan.
1,200-MW Punatsangchhu Stage-I (Puna-I) 1,020-MW Punatsangchhu Stage-II (Puna-II). The 660-MW Kholongchu
Punatsangchhu , Kholongchu
hydropower projects
Puna-I, started in 2008 and expected to be commissioned in 2024-25.
Project delayed due to movement/subsidence of right bank hill mass in the dam area.
The option of providing a barrage in the upstream and abandoning of the dam is being studied.
Puna-II, targeted for commissioning in 2023-24., The HRT for Puna-I was completed in June 2015.
Punatsangchhu , Kholongchu
hydropower projects
While 99.53% of the dam excavation and 98.05% of the underground powerhouse have been completed.
In the case of Puna-II, 99.73% of the HRT and 97.49% of the concrete dam have been completed.
Under condition of anonymity, rethink on the two Puna projects is likely to entail an expensive design change.
Punatsangchhu , Kholongchu
hydropower projects
Pushing for dams reflects the failure of several Indian agencies in comprehensively assessing the fragile Himalayan geology, similar to Sikkim and Arunachal Pradesh flanking Bhutan.
It was a blunder to start a dam at the location that seems to be on the debris of past landslides.
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