More than seven dams in Mysuru and Chamarajanagar districts, mainly Kabini, Taraka, Nugu, Suvarnavathi, Chikkahole, Gundal and Uduthorehal dam, which are more than 40 years old, need immediate attention for better maintenance and structural safety.
Experts rule out an immediate threat to the structure of Kabini dam. However, neglect or delay in filling up the cavity and cracks would weaken the reservoir structure, they caution.
Irrigation department officials noticed leakage and deployed robots and underwater cameras to record the status of the structure, to report to the expert committee and Cauvery Neeravari Nigam Limited authorities, with details that the cracks and cavities are more than 50-cm deep. The engineers could not take up work immediately because of high turbidity in the water and poor visibility to fill up the cracks.
The Dam Safety review team and Dam Safety panel, comprising former chairmen of the Central Water Commission, inspected the dams to study their status.
Due to incessant rain, Chikkahole dam brimmed over but there was no relief for farmers as poor maintenance of sluice gates resulted in wastage of water. The inability to operate or fully close the sluice gate has wasted about 6 cusecs of water every day.
The broken sluice gate of Taraka dam was replaced with a 25-tonne gate 19 years ago. If the government wants to utilise the allocated 284tmcft of water, it should replace all crest gates and strengthen the structure based on the expert committee report.
The Cauvery Neeravari Nigam Limited has approved Rs 32.35 crore for filling up cavities and cracks in the Kabini dam. It has presented a proposal of Rs 88 crore to the Centre to strengthen the dam structures.
Earlier, the authorities traced cavities and cracks in Krishnaraja Sagar reservoir, and leakage in sluice gates took priority to fill the cavities and replace all the gates in phases. However, plans to construct an amusement park at Brindavan Gardens have added to the worry of the stakeholders over the safety of the dam, which was constructed in 1932.
Replace Tungabhadra crest gates
Built over 70 years ago, Tungabhadra dam is showing signs of ageing. A team of experts led by senior hydro-mechanical engineer Kannaiah Naidu has identified several urgent repair and replacement needs.
After the collapse of crest gate 19 in August last year, the committee has recommended the replacement of all 32 crest gates of the dam. The replacement process has begun and is expected to be completed within 15 months.
After the gate failure last year, the dam lost nearly 40tmcft of water. Since then, the storage capacity has been restricted to 80tmcft, impacting drinking water supply in the region. The dam has received heavy inflows over the past two weeks due to significant rainfall in the catchment areas. According to the CWC and expert team, maintaining water storage level at 80tmcft this year will be sufficient to meet agricultural and drinking water needs.