Flash floods triggered by cyclone Michaung has caused significant damage to the second crest gate at the Kandula Obula Reddy Gundlakamma reservoir in Prakasam district.
Late on December 8 (Friday), one-third of the gate was washed away, and officials attributed it to rusting of bolts.
It is the second such incident at the reservoir, the first being in August 2022.
The Government of Andhra Pradesh, as part of efforts to address the issue, had finalised the tenders through the reverse tendering process on December 7, 2023, under which repair of all the 15 crest gates of the reservoir was sought to be undertaken with an estimated expenditure of ₹9.4 crore.
“However, before repair works commenced, the second gate suffered damage on the night of December 8,” R. Muralinatha Reddy, Chief Engineer of the project, told The Hindu on December 9 (Saturday).
“Each gate comprises four horizontal elements, and rust affects the bolts over time. Despite water being potable and in spite of using standard materials, formation of rust persists due to corrosion beneath the thick layer of paint, which requires meticulous inspection to detect damages,” he said.
Mr. Muralinatha Reddy said they had consulted experts in 2022 and repaired the gates 6 and 7 based on their recommendations. The flash floods in August that year had prompted us to use the stop log gates (the extra gates available at the dam) for undertaking emergency repairs when the third gate was washed away. At that time, the dam had retained 1.5 tmc ft water, which was used for agricultural purposes.
“In the aftermath of the first incident, the government had decided to address the larger issue by repairing all the gates, and sanctioned ₹9.4 crore on September 15, 2023. The tenders were awarded to a Gujarat-based company, Hardware Tools and Machinery Projects Pvt. Ltd.,” he added.
However, the cyclone Michaung had brought fresh challenges on December 5, which led to increased inflows into the project from December 6 to 8. With prior knowledge of the dam’s condition, the authorities released half of the floodwaters into the sea, maintaining the storage at 2.3 tmc ft out of the full capacity of 3.8 tmc ft., said Mr. Muralinatha Reddy.
Despite these measures, a portion of the second gate succumbed to the pressure, resulting in significant loss of water, he said.
The gates 2 and 10 were identified as vulnerable, and stop log gates were strategically placed in advance to support them. The breach in the second gate led to a loss of 6,000 cusecs of water, he said, and added that about 1.4 tmc ft water would be retained after the loss.
He further said that there were no standing crops under the project at present, as farmers had been advised not to rely on the dam due to the prevailing drought conditions. The remaining water, even after the loss, would be sufficient for drinking water needs until June-July 2024.
The Chief Engineer expressed confidence that the contractor who had already been awarded the tender would complete the repairs before the next monsoon season.
Though it was expected that the gates should serve for approximately 40 years, authorities were puzzled about the unexpected rust formation.
The Gundlakamma reservoir, which was completed in 2007, had stored water up to its full reservoir level in 2010. It was the first project completed under the Engineering Procurement and Construction (EPC) system, marking a significant milestone in the unified Andhra Pradesh.
