Hyderabad: Srisailam dam authorities have dismissed reports of any threat to the dam on account of water from the reservoir spilling over the dam’s crest gates this Tuesday.
“It was erroneously reported by a section of the media that this was a cause for concern over the dam’s safety. Up to 10 per cent of flood water can safely splash over the dam,” Narayana Reddy told Telangana Today. “The dam is designed with a provision to allow water to splash over,” he said.
Narayana Reddy said there was enough buffer room in the reservoir for the fresh inflows before the crest gates were lifted and there was never any danger or threat to the dam. Usually, the wind over the water spread blows in the same South-Westerly direction as the river’s flow and that resulted in some waves contributing to the splash effect, he explained.
Though Srisailam dam began receiving upwards of two lakh cusecs of water by Tuesday with releases from Karnataka’s dams on River Krishna, the crest gates at Srisailam were not lifted to allow the fresh inflows out via the spillway immediately.
It is learnt that some concerns arising from past experiences in sharing water from the reservoir with Telangana, led to less than the desired amount of water available which AP could draw from the reservoir’s backwater areas to meet needs of Rayalaseema region. Water from Srisailam reservoir is shared by Andhra Pradesh and Telangana with the Krishna River Management Board adjudicating releases from the reservoir based on the indents placed by the two States.
Plunge pool check put off
Meanwhile, a proposed visit this month by a team of dam safety experts to study the large plunge pool pit, formed by water falling from the Srisailam dam spillway, has been put off. “The visit will happen once we get the report with some clarifications we sought from National Institute of Oceanography on the subject,” according to Chief Engineer (Projects) Kurnool, Ch Narayana Reddy.
The team was scheduled to visit the Srisailam dam on September 18 for an inspection of the apron and plunge pool areas and possibly make some recommendations on safety measures. The report with clarifications sought is expected to be received by the dam authorities in the next fortnight or so.
It may be recalled that two teams from NIO – one from Goa and another from Visakhapatnam – had earlier this May studied the large plunge pool pit carved over the years by water from the dam spillway. While NIO Goa shot underwater videos of the pit in a bid to find out more information about erosion inside the pit, the team from Visakhapatnam conducted a bathymetric survey to establish the spread and shape of the pit and its contours.
It is learnt that at its widest, the pit is more than 200 metres wide and its length extends to about 400 metres. At its deepest portion on the right bank of the river on the Andhra Pradesh side, the pit is said to be as deep as 40 metres. The depression is said to begin some 100 metres after the dam structure on the river bed.