Chennai: With the southwest monsoon rains more than predicted this year so far, and inflows into the Mettur reservoir surging in the last few days thanks to rains in Karnataka’s catchment areas, a noted water expert has urged that Tamil Nadu government should plan ahead to ensure that sudden flood flows into the Cauvery do not again go unutilised into the sea.The water level in the Mettur reservoir rose to 81.33 feet, against its full level of 120 feet on Thursday with inflows into the dam being 19,712 cusces, according to PWD sources. Even if this has come about in late June, “we can expect a huge flood discharge of 50,000 cusecs to one lakh cusecs in a week or two if the monsoon trend persists,” says Dr. P.M. Natarajan, a member of the working group of Tamil Nadu Planning Commission.
The last time the Stanley reservoir in Mettur reached its full level of 120 feet was on August 5, 2013, when just one day’s flood flow was 1,35,000 cusecs (11.66 tmcft in one day flow), he pointed out in a paper that he shared with DC. Keeping track of the inflows into Mettur even while being on a tour abroad now, Dr Natarajan said Tamil Nadu invariably has been receiving only excess flood flows from Karnataka, virtually year after year.
This year there was a possibility of Mettur getting filled earlier than it did in 2013. But the persisting paradox in the Cauvery delta has been that Tamil Nadu has been unable to harvest the floodwaters released by Karnataka “due to the absence of adequate irrigation tanks to store the water” and the huge inflows were mostly let into the sea. Giving a recent example, Dr Natarajan pointed out that even in 2013, which was comparatively a drought year, after Mettur dam had reached its full level, between August 4 and August 8, about 17 tmcft of floodwaters was let out into the sea. The quantity was a huge agriculture loss, given that one tmcft of water is valued at Rs 50 crore in paddy production terms, he noted.
This was also notwithstanding the fact that people were suffering for even drinking water in Cauvery delta, more so in the tail-end and nearby Pudukottai district. Dr Natarajan suggested that the barrage at Mayanoor in the Cauvery river has to be made effective by constructing the feeder canals to take the excess flood waters to Pudukkottai, Sivaganga and Ramanathapuram districts.In their absence, the “best option available now” was for water managers “to plan early” for diverting anticipated flood flows in the Cauvery this year through the recently rejuvenated ‘Grand Anicut (GA)’ canal, to the southern part of Pudukkottai district which has sufficient irrigation tanks, Dr Natarajan suggested.
