Dam safety panel for additional spillway

To protect the existing dam structure and avoid the possibility of the dam breaking in the event of a major flood in Krishna river, Nagarjunasagar Dam Safety Panel chairman M.S. Reddy recommended the construction of an additional concrete spillway on the earthen dam.

Speaking at Nagarjunasagar Dam on Monday, the former Central Water Commission chairman and former secretary to the Ministry of Water Resources said, in order to protect the existing 26 spillway gates from breaking, an additional spillway construction is the only solution, by building a concrete spillway for about 600 metres on the left bank of the earthen dam, so that during heavy floods like in 2009, water can be diverted to downstream Krishna river through Tiger Valley.

He said that in 2009, it was estimated that 25 lakh cusecs of flood water was recorded against the dam’s full capacity of 13 lakh cusecs.

“Nagarjunasagar dam spillway bucket portion is already damaged, it cannot cope with major floods, which was evident in 2009 floods. There is also a power house situated below the spillway, in case of major floods over and above 13 lakh cusecs occur, it will be dangerous for the existing concrete spillway structure and there is likelihood of the dam breaking,” M.S. Reddy said.

He said there is a possibility of flood water flowing over the top of the spillway, endangering both concrete and earthen structures.

He said after the historic 2009 flood, IIT Roorkee had conducted studies and planned to take further steps to protect the dam structures.

When asked about the fate of Srisailam Dam, which was constructed in the gorge portion of the river, M S Reddy said,

“There was a separate technical experts committee constituted and something needs to be done to release additional flood water into the downstream river by constructing major tunnels to control the flood.”