The students from Hyderabad were caught unawares by the unscheduled release of water from the run-of-river hydel plant at Larji as they stopped at a temple near the village of Thalaut, en route to the popular tourist town of Manali. The release of water should have been preceded by the plant sounding sirens. But the surviving members of the party and villagers at the scene say there were no warnings. The plant at Larji is operated by the Himachal Pradesh State Electricity Board.
The failure of the warning system is a matter of concern because such rushes of water are a routine feature of run-of-river hydel projects.
ROR projects have come up in great numbers in Himachal Pradesh and Arunachal Pradesh in recent years because they are usually considered better for the environment than big dams like Bhakra or the Narmada Valley projects: they don’t submerge large areas of land or greatly reduce downstream flows. The growth in the number of such projects has been driven by India’s continuing power shortage and the high revenues mountainous states can earn through these.
A report published in World Rivers Report in March said that India’s Himalayan belt is suffering from a “Memorandum of Understanding Virus”. “Hundreds of agreements have been signed and great stretches of rivers apportioned to private and public enterprises,” it said.
Unlike big dams, ROR hydel electricity projects provide little or no water storage. Dams are relative small. ROR projects work by diverting the river flow into a desilting chamber, then carrying it via tunnels to turbines, where electric power is generated. The water is then taken, via what is called a tailrace tunnel, to a suitable spot further along the river’s flow.
The plant at Larji was an ROR project that provided some storage, and consequently served as what is called a peaking power plant. Peaking plants are generally run only when there is high demand – in industry parlance, peak demand – for electricity. Because they supply power only occasionally, the power supplied usually commands a much higher price per kilowatt-hour than base load power.
However, the design of such projects has two effects that, in combination, could repeatedly result in deaths unless great care is taken to ensure that both residents and visitors to the area are aware that the riverbed could flood within minutes. It is important to consider why the group from Hyderabad were standing amid the rocks there – reportedly relaxed, and taking photographs of one another – in the first place. Because an ROR project takes water off-course, to the turbines, it creates a lengthy stretch of riverbed where the water comes by in little more than a relative trickle. Certainly, it does not seem threatening to a casual visitor. It was just this kind of stretch that this unfortunate group found themselves in.
Second, because there is no large reservoir holding the water, dam operators have to release the water once the storage is nearing capacity. In this case, the resident engineer of the Larji plant, Mandeep Singh, since suspended, told CNN-IBN that they were suddenly forced to open the sluice gates because there was an unanticipated drop in electricity demand. Because it was functioning as a “peaker”, when demand fell unexpectedly, the water was no longer needed to generate electricity – and the gates had to be opened.
Of course, such tragedies are avoidable if proper safety procedures are adhered to. Residents must be kept informed of water releases and proper warning signs are needed all along the section of the riverbed that is dried out, especially in areas where tourists gather. Sirens to signal the imminent release of water are also essential.
Villagers from Thalaut, angry about the deaths and fearful they could be affected similarly, blocked the highway on Sunday night. Groups of villagers insisted to journalists that the sirens did not sound. Speaking to the press on Monday, chief minister Virbhadra Singh said, “This is the first time such a tragedy has happened, which is unfortunate.”
Yet, activists claim that deaths are not uncommon. “Such incidents have happened in Himachal Pradesh, Karnataka, Tamil Nadu, Uttarakhand and Madhya Pradesh,” said Himanshu Thakkar of the South Asia Network on Dams, Rivers and People. “The truth is not one official has been appropriately punished in India because of deaths due to the wrongful operation of a dam.”