Cauvery is not just a river for lakhs and lakhs of farmers of Karnataka and Tamil Nadu. It is a life line. During times of drinking water crisis both the sister cities of South India, Bengaluru and Chennai, have taken the help of Cauvery. But it is also essential to mention Cauvery basin in the current dammed form is only about a century old. Krishnaraja Sagar Dam was built between 1911 and 1932. Similarly Mettur dam was built between 1925 and 1934. Interestingly for only twice, since KRS became operational in 1932, the sluice gates have been opened during the month of June. The first instance was during the year 1941 when like 2025 Monsoon made onset during the 3rd week of May. Yesterday after 84 years KRS sluice gates were opened during June.
Over the years it has always been a practice to put Cauvery specific posts at COMK. One of the reasons for these post is to not only keep a tab on the status but also provide a perspective. Over the past few years we have seen Cauvery Basin swing wildly. From the floods of 2018 to the drought of 2023 when cumulatively only 154 TMC inflow was realised. It is in this context one should look at the opening of KRS dams sluice gates yesterday.
The current state of near FRL across the Cauvery Basin is due to the early monsoon onset and a fairly strong June so far. But that has always not been the case. The average storage level in the Cauvery Basin dams of Karnataka is 20 TMC at the start of the irrigation year over the past decade. This year the cumulative storage in Karnataka dams was 73 TMC at the start of this irrigation year.
If one were to look at the weather model outlooks for the next couple of weeks the Monsoon Intra seasonal oscillation is expected to favour Central India. This could mean while monsoon may not completely shut down over Peninsular India it may remain sub part until first week of July. A possible fresh genesis of MJO over the Indian Ocean coupled with a more traditional propagation may bring back impetus to monsoon dynamics over Peninsular West Coast. Until then it may be prudent to have a measured exuberance over the current storage levels across the Cauvery Basin dams.
On the immediate weather front moderate rains may continue over Peninsular West coast. Partly cloudy skies may keep temperatures under check for leeward plains of Tamil Nadu. Moisture incursion from the west may bring about a spell or two of rains over isolated pockets in South Coastal TN and North TN. With stiff westerlies these could be shorter duration intense burst of rains when they happen.