Once again, after several such incidents in the past, the controversial 2000 MW Lower Subansiri Hydropower project on Assam Arunachal Border was hit by a massive landslide at around 11.30 am on Oct 27 2023. The landslide damaged the project, further delaying the commissioning of the first unit, increasing the cost and time over runs of the expensive, much delayed project. Following the landslide, the only functioning diversion tunnel no 1 of the project, about 200 m upstream from the dam was blocked. The river water, about 997 cumecs (cubic meters per second) suddenly started flowing towards the dam, where the spillway gates were still under installation, yet to be tested. The water could overflow from the under construction spillway gates once the reservoir reached 145 meters level (above Mean Sea Level). The massive, majestic Subansiri river was completely without any flow till the river water started flowing through the spillway gates about twelve hours later. (Feature photo above shows the snapshot when landslide started and in the foreground, water is seen rushing towards the dam)

Assam Rajya Sabha MP Ajeet Bhuyan, referring to the October 27 landslide said in his letter to Prime Minister that the incident is only a warning, which can’t be ignored: “The hilly soil of Arunachal is fragile. Secondly, the dam site is earthquake-prone. Thirdly, the base of the dam was reduced by 09 metres without any public explanation. These are enough indications for a major disaster in the coming days”. On Oct 31 2023, he appealed to PM to take swift measures and fix accountability. He reminded PM that Mr Modi himself had said in 2014 no big dams in North East if people do not want. He also reminded that current Defense Minister Rajnath Singh had also said they will scrap the project. Mr Bhuyan said that he apprehended much bigger disaster than recent Sikkim Disaster if this projects goes ahead.