• 1 cusec = 28.32 litres flow per second
• 1,000 cusecs = 28,320 litres per second
• 20 hours (per hour 60 minutes. 60 seconds per minute), so it is 72,000 seconds for 20 hours
• Litres: 28,320 litres x 72,000 seconds
• Total litres: 203 crore 90 lakh 40 thousand litres

KRS crest gate 5 remains open for over 20 hours; probe ordered 

Mysuru: Even as the washing away of a crest gate at the Tungabhadra Reservoir in Vijayanagara district in August 2024 remains fresh in public memory, over 1,000 cusecs (cubic feet per second) of water was discharged into the river from one of the crest gates at the Krishna Raja Sagar (KRS) Dam for more than 20 hours in hot summer — without the knowledge of the officials managing the Reservoir.

The incident occurred at Gate Number 5 (at 80+ level) of the KRS Dam from Sunday evening to Monday afternoon. The gate was finally closed on Monday evening after a strenuous struggle by workers due to the powerful water force. An investigation has been ordered to determine if there was any lapse on the part of the officials.

On Mar. 20, the Cauvery Neeravari Nigama Limited (CNNL) officials, who manage the KRS Dam, released 4,187 cusecs, followed by 4,181 cusecs on Mar. 21, 4,174 cusecs on Mar. 22, 4,161 cusecs on Mar. 23, and 4,149 cusecs on Mar. 24. Approximately 2,400 cusecs were directed to the canal for irrigation purposes, while 1,750 cusecs were released for drinking water.

On Sunday (Mar. 23) evening, due to heavy rainfall in the Kodagu catchment area, Dam authorities decided to close all crest gates to accommodate the expected inflow. However, Gate Number 5 (at 80+ level) remained open, causing over 1,000 cusecs of water to flow into the river unnoticed. Officials only realised the lapse on Monday morning (March 24) and scrambled to close the gate.

After several hours of struggle, the gate was finally shut by evening. By Tuesday morning (March 25), the Dam’s outflow was recorded at 5,017 cusecs. On Wednesday (Mar. 26), a normal outflow of 4,130 cusecs was recorded. 

Investigation underway

A probe has been ordered by CNNL higher officials to determine whether Gate 5 (at 80+ level) was deliberately opened or if it was an accident. A report has also been submitted to the State Government, CNNL Superintending Engineer Raghupathi confirmed to Star of Mysore.

According to statistics, 11,574 cusecs of water equals 1 tmcft (thousand million cubic feet). If 4,000 cusecs are released daily for 3 days, it amounts to 1 tmcft. Typically, the Dam releases 0.35 tmcft daily for irrigation and drinking water purposes. However, between Mar. 23 and 24, 0.43 tmcft was released — 0.082 tmcft more than the regular discharge.

Raghupathi confirmed that the loss of around 1,000 cusecs of water due to the accidental discharge will be compensated by blocking water release at check dams downstream. However, the data from Mettur Dam in Tamil Nadu shows that from 8 am on Mar. 24 to 8 am on Mar. 26, it received an excess inflow of 500 cusecs.

Notably, despite extensive modernisation efforts, the KRS Dam still faced this lapse. Under the Dam Rehabilitation and Improvement Project (DRIP), 136 crest gates of the KRS Dam were replaced with financial support from the Centre and the World Bank, which provided Rs. 69.52 crore in aid.

Yet, Gate 5 (at 80+ level) remained open for over 20 hours without the officials’ knowledge, raising concerns over the effectiveness of the modernisation.

Storage capacity

On Mar. 26 (today), the storage capacity of the Dam stood at 27.970 tmcft (106.09), against its maximum capacity of 49.452 tmcft (124.80 ft). However, only 19.591 tmcft is classified as live storage, while the rest is dead storage. When asked about the current water level and its ability to meet the drinking water needs of Mysuru and Bengaluru for the next two months (April and May) until the monsoon, Raghupathi assured that from Apr. 1, water release for irrigation will be in batches, based on the requirement.

The remaining supply, he said, would be suffice until monsoon, which may arrive early this year.