Nearly nine months after the National Dam Safety Authority (NDSA) flagged of a potential threat to the structural stability of the 40-year-old Srisailam dam built on Krishna River between Andhra and Telangana districts due to damages caused to the project over the years, the Union Jal Sakthi ministry swung into action to repair the damages, people familiar with the matter said.
The Union ministry last week constituted a technical expert group (TEG) to provide technical guidance and advice on appropriate remedial measures for the rehabilitation of the plunge pool of the Srisailam project.
The TEC is headed by Central Water Commission chief engineer (designs) Vivek Tripathi, and comprises – Somesh Kumar, Samarth Agarwal, Arun Pratap Singh, Madhukant Goyal (from Concrete Masonry Dam Design Directorate), Manish Gupta from Central Soil and Materials Research Station (CSMRS), M K Verma from Central Water and Power Research Station (CWPRS) – M.K. Verma and Shailendra Singh from Geological Survey of India (GSI) – Shailendra Singh.
The committee also comprises chief engineer (projects), Kurnool, Water Resources Department, working in Srisailam project, besides chief engineers from Telangana irrigation department and Krishna River Management Board (KRMB).
An irrigation department official familiar with the matter said the experts committee will examine and recommend restoration measures for the dam’s severely damaged plunge pool and apron, following recommendations made by the NDSA.
{{/usCountry}}An irrigation department official familiar with the matter said the experts committee will examine and recommend restoration measures for the dam’s severely damaged plunge pool and apron, following recommendations made by the NDSA.
{{/usCountry}}On April 29 and 30 last year, a team of top officials of the NDSA led by its chairman Anil Jain visited Srisailam project site to inspect the damages caused to the project over the years. The NDSA team expressed serious concern over the situation and indifferent attitude of the authorities over the dam safety.
The authority submitted a detailed report to the state government and also Union Jal Sakthi ministry in May 2025, highlighting that despite repeated assessments over the years, restoration measures had not been implemented.
The technical review report of the NDSA, which was reviewed by HT, has identified several critical issues about the safety of Srisailam dam. According to the report, the inspection revealed significant damage to the plunge pool and downstream protection systems.
The plunge pool is the area where the water released from the dam and hits the rock bed in the apron (front portion of the dam). “The water gushing out of the gates located at such a height has tremendous kinetic energy and when it falls on the plunge pool, it rises up again to a great height before falling down again,” the official quoted above said.
The water gushing out of the crest gates when the reservoir is filled to the brim, resulted in a huge crater due to the massive impact of the water pressure.
The NDSA team found that a large pit has formed from about 50 metres downstream of the apron end, extending up to 220 metres. The plunge pool depth has increased dramatically from 122 metres to nearly 160 metres.
To prevent further erosion and protect the spillway, the NDSA team recommended replacing 39 protective cylinders installed in the plunge pool region. The report warned that continued neglect could lead to further damage to the spillway structure.
In October 2009, Krishna River witnessed unprecedented floods at Srisailam. The dam, designed for a maximum flood discharge of 19 lakh cusecs, had witnessed a flow of 25.5 lakh cusecs. The irrigation engineers had to fully open all the 12 radial gates to the maximum extent to release the entire water at a high speed. This had resulted in the disturbance of the plunge pool and the crater in the apron had become huge.
The scour-induced undercutting of the concrete apron could compromise spillway toe stability and possibly lead to structural distress or progressive failure.
The inspection team also found a high degree of clogging in the foundation drainage system and most parts of the foundation gallery remains largely unmaintained. The team also noticed seepage of water to the extent of 757 litres per minute in the gallery, which is significant given the potential uplift pressures it could induce.
Though the NDSA flagged the damages in May itself, the Andhra Pradesh and Telangana governments did not pay much attention to the repairs. “In the months of July, August and September, 2025, there were heavy inflows into Krishna River at Srisailam reservoir, forcing the authorities to release more than three lakh cusecs of water by opening multiple crest gates. This resulted in further damage to the plunge pool, destroying the cylinders to a large extent and posed a threat to the dam foundation itself,” another engineer familiar with the Srisailam project said.
Although the Srisailam Project is currently under the management of the Andhra Pradesh government, the dam is strategically important for both states, making inter-state coordination essential.
The Union Jal Sakthi ministry said the broad scope of work to be undertaken by the TEG, among other things, includes a detailed technical review of the plunge pool condition and damage assessment; studying relevant case studies around the world to derive lessons learned and applicable best practices and recommending suitable rehabilitation measures based on multidisciplinary inputs.