Excess rains caused killer floods, say CWC & KSEB

THIRUVANANTHAPURAM: The worst flooding in a century was caused by heavy rains and not by the opening of dams, said the Central Water Commission director (flood forecast monitoring) Sharad Chandra in New Delhi on Wednesday. The Kerala State Electricity Board Limited too has come out with fresh statistics to bolster the theory endorsed by the commission.

“The opening of dams did not lead to the floods. It was caused by the heavy and incessant rains. Topographical characteristics of the state too would have played a crucial role. Even if dams were opened earlier, it would have made little difference. We are awaiting more details from the state,” said Chandra. The final report on the floods would be submitted to the Union government, he added.




Meanwhile, the KSEB has come out with a fresh set of data and arguments against the theory that the board’s greed and oversight contributed heavily to the inundation. Percentage wise, the presence of impounded water released from dams was miniscule, compared to the floodwater that flowed into the rivers from elsewhere. The maximum water the board could have safely released from the Idukki dam, if it had chosen to open the shutters in advance, would have been just 10% of the cumulative water discharged from the dam from August 9 to 28, the board claimed.

To let water from Idukki dam flow through the shutters, the water level in the dam should be minimum 2,373ft. The water level in the dam reached that level on July 17. For argument’s sake, if the board had decided to open the dam shutters and released a moderate 50-100cumecs of water from July 17 to August 9 (water discharge should have been restricted so as to ensure that it doesn’t inundate Cheruthony bridge), it could have drained only 95mcm of water from the dam. This would have accounted for only 10% of the total volume of water (939 mcm) released from the dam from August 9 to 28. This, according to the board, would offset the argument that controlled releasing of water from the dam over a longer period would have helped to avoid the flooding to an extent.

While 1,186mcm water flowed to Idukki dam from August 14 to 19, only 525mcm water was released from the dam. The rest 661mcm of water was held back in the dam. In a way, it helped to control the flood-level in Periyar River, the board claimed. Citing the volume of flood water that reached the downstream from sources other than dams, the board claimed that while only 2,900cumecs water was released from Idukki and Idamalayar together, the water flowed out of Boothathankettu barrage was 7,700 cumecs. Only 56% of Periyar’s catchment area is above Bhoothathankettu. The kind of water that flowed from the rest 44% of catchment area to the river below the barrage would have made a huge impact.

Likewise, over 5,080cumecs water flowed through Pampa river, whereas the total volume of water released from Pampa and Kakki dams was only 1,473cumecs, the board said. Similarly, the water released from Banasurasagar dam accounted for only 12% of water that flowed to Kabani River, board claimed.