Tamil Nadu

Shutter thickness, corrosion that escaped inspection led to KRP Dam breach

Works to fix the shutter in KRP Dam under way in full swing on Monday.   | Photo Credit: N. Bashkaran

On November 29, Shutter I of KRP Dam breached, when the reservoir was filled to its full capacity of 52 feet. As the water pressure threatened to damage the dam structure, the Public Works Department, in-charge of the dam, drained the reservoir by controlled release of water through all the eight shutters of the dam into Thenpennai River.

Soon after the storage level dropped to 32 feet, the damaged shutter plate was dismantled. This metal plate was to contain the water in the reservoir.

It was found that the 24-feet metal plate had varied thickness - its top was 60mm, middle was 11mm, and the sill had barely 6mm of thickness. The breach was at the sill level.

The KRP Dam was inspected two years ago by a Committee of Central Water Commission (CWC) to commission repairs under the Dam Rehabilitation and Improvement Project (DRIP) funded by the World Bank. Repair works for ₹ 1.10 crore were accomplished on KRP Dam.

The highly corroded metal plate flags possible lapses in the inspection by the Central committee.

Official sources in the PWD told The Hindu the CWC committee consisting of Central and State officials had reportedly inspected the dam when the reservoir was full.

“The dam was inspected superficially by the committee when the reservoir was full. The corroded part was submerged in water,” said a PWD source. “The water pressure is at its highest at the sill level, and this is also where the metal was most corroded.”

There needs to be better interaction with the field level officials and the Committee to understand location-specific needs of dam safety, the official says.

According to another PWD source, the water quality in Pennayar river is generally poor, with effluents drained from Bengaluru. Then, these location-specific factors were ignored and the inspection to designate works for dam safety was not comprehensive.

Dam safety has become an issue only now, says a PWD official. Post this incident, PWD has proposed to the government to issue funds under the head of structural safety of dams. Funds are currently allocated under “system maintenance”. These funds were utilised downstream for repair of sluices, and never for structural safety of the dam. Also, works are taken up at the last minute with no proper study, the official add.


In an earlier version, the shutter thickness was wrongly given as metres. It has been changed to mm

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Printable version | Feb 27, 2021 9:38:29 AM | https://www.thehindu.com/news/national/tamil-nadu/shutter-thickness-corrosion-that-escaped-inspection-led-to-krp-dam-breach/article21910144.ece

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