Suspends plunge pool work at Srisailam
Hyderabad:Amidst a sense of urgency for an in-depth study of the huge problem associated with the plunge pool at the Srisailam dam, irrigation department officials had anxious moments on Tuesday when a cableway used to carry men and material down to the ‘lip’ section of the structure, stopped functioning.
The plunge pool has formed at a spot where water released from the dam falls with great force and speed. Studies have found that the roaring water has also opened up cracks in the scouring which are extending towards the dam structure. Some of the scouring was found to be deeper than the dam’s deepest foundations.
The cable way is the only means for access for men, and materials down the dam’s apron, and towards the huge plunge pool that has formed just downstream of the structure, and which has emerged as a major cause of concern for the dam’s stability and safety.
The glitch left representatives from the Central Water Commission (CWC) and scientists from Central Water and Power Research Station (CWPRS), Pune, wondering if they could proceed with the work. The CWPRS, a senior irrigation official said, will conduct a bathymetric survey of the plunge pool to study afresh its contours, depth and extent of the void, and submit a report, based on which the next course of action will be decided upon.
By the evening, the cable way system was revived and was working, the officials said. It was being tested to ensure its safety for work that is expected to begin on Wednesday.
A team of officials from the CWC and CWPRS scientists were at the dam on Tuesday to examine the problems plaguing the structure for the past several years. During the first week of last month, a team of officials from the National Dam Safety Authority (NDSA) who visited the dam, gave a detailed note on the issues that required urgent attention before the flood season started for the Krishna river.
Incidentally, the NDSA, in its note, also flagged the need for repairs to the cable way saying its “functionality” required to be attended to. It had further said that issues related to the cable way were also taken to the notice of the dam authorities in the past.
The increased activity to study the problems plaguing the dam — that straddles River Krishna which forms the border between Andhra Pradesh and Telangana — and finding solutions, follow repeated flagging of these issues by the Telangana irrigation department which took the matter to NDSA’s notice multiple times.
Infograph
Srisailam dam concerns
Huge plunge pool gas formed just after the dam, with cracks from scouring extending towards the dam structure.
Some of the scouring found to be deeper than the dam’s deepest foundations.
Exposed aggregates under Gates 4, 5, 9 and 10 of the dam, which NDSA said could become worse if water was let out from gates.
Choked drainage holes in the foundation gallery, impacting dam’s uplift pressures.
