Cauvery – Early season pangs hit once again

Cauvery
Reading Time: 4 minutes

Cauvery the river brings forth different emotions to different people. For many in South India it is possibly the most sacred river, pretty much on par with River Ganga. To the farmers of both Karnataka and Tamil Nadu it is the lifeline of their sustenance. To the water managers of the two states it is a potential flashpoint every year during Southwest Monsoon. But with the dams like KRS and Mettur the river is now in the control of the reservoir managers. But time to time the river decides to break the shackles and roar its way towards Bay of Bengal.

Most of us cannot forget the pitched battle the two states fought in the Supreme Court a few years back. If only Cauvery the river had someone like the famous advocate Parasaran, who represented Ram Lalla in the Ram Janmabhoomi case, the river may have had a chance to present its side of the story. A river struggling to live up to the ever growing demands from both the states thrust upon it. The river now not only has agricultural demands to fulfill but also growing drinking water needs as well. As a monsoon fed river the water flow in Cauvery is hugely dependent on the monsoon dynamics. Since inception COMK has covered many aspects of this wonderful river and its struggle to find a voice for itself.

One of the biggest millstone around the neck of Cauvery is the Mettur dam opening date of 12th June for Kuruvai cultivation. In a couple of months time Mettur would be completing 90 years of serving Tamil Nadu. During this 90 years less than 1/4th of the years the dam was opened on 12th June. Ironically 2024 is the first time Mettur did not open on 12th June in the past 5 years. The previous 4 years saw storage of above 60 TMC in Mettur allowing the opening of the dam. In the past decade those were the only years dam was opened on schedule.

The average storage in Mettur and Karnataka dams cumulatively around 1st June during the past decade has been 48 & 20 TMC. With this storage it is always less likely to open the dams on schedule for Kuruvai cultivation. Dig a little deeper we can also see even by mid July the storage does not drastically change. While in 2015, 2018 and 2022 Karnataka dams had good storage only during 2018 and 2022 Mettur saw atleast 70 TMC. The situation becomes much better by mid August when 6 out of the past 10 years Karnataka dams were near FRL. Similarly 6 out of 10 years Mettur also saw near 2/3rd storage by Mid August.

As weather enthusiasts it is always essential to take a rational and unbiased approach while analysing issues. Only during 2017 and 2018 in the past decade Mettur storage was lesser than the cumulative storage of Karnataka dams by 1st June. This highlights the difficulty in Tamil Nadu receiving its share of waters during the early monsoon season. Kabini offers the best hope for early inflows into Mettur with a much lesser storage compared to KRS. But for Kabini to fill up fast we need strong Monsoon in Wayanad during June. With trends pointing out to late season monsoon flourish over Kerala this probability has started reducing as well off late.

Leaving the date of opening aside, the biggest challenge is sustained availability of water during Kuruvai season. The past decade storage data indicates it is only during the 2nd half of SWM season this may be possible. In this context it makes long term sense to revisit not only the Kuruvai cultivation period but also the traditional opening date for Mettur. Any change may require a bit of short term sacrifice and a lot of long term planning.