Cauvery springs back to life as Mettur fills up

CHENNAI: Burst of monsoon in the catchment area of Cauvery and its tributaries in Kerala and Karnataka saw Stanley Reservoir in Mettur reaching the brim after a gap of 18 months, forcing the authorities to divert the surplus water downstream.

However, the quantity and velocity of the water let down in the Cauvery river from Mettur is expected to rise rapidly from 23,000 cusecs to 81,500 cusecs by 8 pm on Tuesday. About 21,500 cusecs of water will be released through the dam powerhouse and tunnel powerhouse, while the balanced quantity of water released through Ellis saddle surplus gates.

In anticipation of receiving an inflow of around 1.5 lakh cusecs issued a flood alert to the people living along the banks of river and low-lying areas in the Delta districts to move to safer places.

“There is a likelihood of releasing surplus water to Cauvery river from 75,000 cusecs to 1.25 lakh cusecs and this may be increased at any moment,” said a WRD official in a communication.

The 90-year-old reservoir last filled up on December 29, 2022, and the water level plummeted to 39.760 feet on July 6, 2024. This is the 43rd year the dam has filled up in history. The department on Tuesday evening decided to increase the outflow from Mettur dam from 23,000 cusecs to 46,000 cusecs from 6 pm. The quantity of water discharged would be further increased to 66,000 cusecs and 81,500 cusecs with effect from 6 pm and 8 pm respectively.

At about 5 pm, surplus water to the range of 80,000 cusecs was discharged from Kabini and 1.20 lakh cusecs of water from the KRS reservoir. It would take eight hours for the water to reach Mettur, which is 225 km downstream from the Kabini dam and 275 km from the KRS dam.

“Going by the quantity of water discharged from Karnataka reservoirs, we will be seeing nearly 2 lakh cusecs of water in Cauvery river in TN by Wednesday noon,” said a source, citing the surplus water from Kabini and KRS reservoir. Meanwhile, water managers and experts came down heavily on the Tamil Nadu government for discharging less quantity of water from the Mettur dam despite knowing the situation in Kerala and Karnataka. It shows that the government was concerned about sustaining the water release for the entire harvest season -- Samba crops.

“We need water from October 15 for Samba crops. Whatever the quantity of water discharged now can only be beneficial to replenish the dry riverbed and enhance the groundwater level, besides filling up waterbodies.

But most of the linking channels are not maintained properly to carry the water to the ponds and tanks in the Delta region,” said PR Pandian of the Tamil Nadu Federation of All Farmers’ Association.

Meanwhile, Salem Collector R Brindha Devi released water into the dam’s canals to irrigate 45,000 acres in Salem, Erode and Namakkal districts.

Sowmiya Anbumani, president of Pasumai Thayagam, an NGO, who visited the Mettur dam urged the state government to implement schemes to save surplus water discharged from the reservoir.

with inputs from Ashok Kumar in Coimbatore