There were two unusual events that preceeded the decision by the operators of HPSEB’s 126 MW Larji hydelpower project to open the floodgates of the project’s reservoir, which washed away over over two dozen students from Hyderabad in the resultant flash flood on Sunday evening.
One, the project suddenly reduced generation of power at about 6 pm, presumably because the demand had dipped. At around 5:50 pm, the state load dispatch centre at Shimla reportedly asked the Larji authorities to reduce power generation as it had touched 138 MW against its installed capacity of 126 MW. Consequently, two of the three units were shut down.
Then inexpicably, at around 6:15 pm, the operators decided to open the floodgates at the bottom of the project’s reservoir as they realised that it was full to the brim.
While an enquiry has been ordered and three persons — engineers M S Dadwalia and Mandeep Singh and technician Harbans — have been suspended, the most apparent mistake appears to be the decision to stop power generation at a time when the reservoir — which has a small storage of 1-2 days — was nearly full.
Second, given that it is peak summer, if the small reservoir of the plant was full, it points to the possiblity of the plant not working optimally, resulting in sub-optimal management of the water levels in the reservoir. To compound the lapses, the authorities reportedly did not use high velocity hooters and sirens on the release of water, as is laid out in the protocol.
According to reports, the project authorities had been releasing excess water in the Beas, almost without prior warning, since Friday. So on Sunday evening too, they followed the same practice, not realising the tragedy that was waiting to unfold, just 2.7 km downstream at Thalout, on the Mandi-Kullu-Manali National Highway.
“The state load dispatch centre at Shimla received an SOS from the national load dispatch centre to lower power generation at Larji to save the grid. The resident engineers at the project passed the orders and the floodgates were opened after a blaring siren,” claimed Pratap Negi, chairman-cum-managing director, HPSEB Ltd.
But the surviving students of Hyderabad’s V N R Vignana Jyothi Institute of Engineering and Technology said there was no warning. The water level rose so fast that the students could not run to safety, they said.
“I noticed a rise in the water level and alerted the students. It was just two or three minutes later that huge waves of water hit the high rocks, where students were standing to click pictures,” said Kiran, a senior faculty member.
“Prima facie, there seems to be enough reason to suspect gross irresponsibility on the part of the operators of the Larji station. The enquiry underway is likely to point to these technical issues in the run-up to the events leading to the sudden opening of the reservoir’s floodgates,” said a central government official involved in grid operations.
“I wonder if the project authorities were adhering to standard operating procedure during regular high water discharge. This is peak tourist season and it’s never safe to release water like this. How do the tourists know about such dangers?” said Mandi Divisional Commissioner Mandi Onkar Sharma, who is now the inquiry officer.