The new vented dam across the Netravathi at Thumbe is expected to be ready by the end of 2013, according to L.N. Anand, Executive Engineer, Karnataka Urban Water Supply and Drainage Board (KUWSDB), Mangalore.
Speaking to presspersons at Thumbe on Tuesday on the sidelines of Ganga Pooja to the river organised by Mangalore City Corporation, Mr. Anand said that 25 per cent of the construction work had been completed.
The work was started in 2010 and the cost now has escalated to Rs. 79.50 crore as against the earlier estimate of Rs. 40 crore.
Mr. Anand, who is supervising the construction work, cited four reasons for the cost escalation. The height and depth of the dam is now being increased.
Use of quality grade concrete and the higher premium quoted by the contractor have contributed to the cost escalation. The tendered amount stood at Rs. 48.21 crore.
The Executive Engineer said the height of the dam would be increased from 10 metres to 12 metres to make it flood-resistant. The maximum flood water level recorded in Thumbe was 11.79 metres in 1974.
He said the maximum storage level at the dam would be seven metres with a storage capacity of 14.75 million cubic metres as against the existing 4.89 million cubic metres. Even if there was zero inflow, the city could be provided uninterrupted water supply for five months.
He said the new dam would have electrically operated mechanical gates.
Advisor
He said the KUWSDB was seeking the advice of Sankappa Shetty, retired Chief Engineer, Karnataka Power Corporation Ltd. (KPCL) while building the dam. Its foundation structure was being inspected and certified by the geologists (of General Manager level) of the KPCL at regular intervals. Quality of construction was being inspected by the authorities of Indian Register of Shipping which was the third party inspecting agency.
Tor Steel Research Foundation in India had designed the dam. Rithwik Projects Ltd. and Swapna Constructions (Joint Venture) of Hyderabad was building the dam.
When water was stored in the new dam, 69.48 hectare of revenue land and 364.29 hectares of river area would be submerged.
Mayor Praveen and Deputy Mayor Geetha Nayak performed Ganga puja. The Commissioner of the corporation Harish Kumar K. was present.
