Mysore/Mysuru: Water levels in the four major reservoirs of the Cauvery basin — Harangi, Krishna Raja Sagar (KRS), Kabini and Hemavathi — have fallen to less than half of their total gross capacity. This downturn serves as a stark indicator of an impending crisis in the months and weeks to come.

The available water supply not only needs to cater to the drinking water needs of major towns and cities, including Bengaluru, Mandya and Mysuru, but it must also last until the onset of next year’s monsoon in June.

As of yesterday (Nov. 22), the cumulative storage in the KRS, Kabini, Hemavathi and Harangi stood at 56.55 thousand million cubic feet (tmcft), as against their total gross capacity of 114.57 tmcft. In comparison, the storage level on Nov. 22, 2022, was 97.45 tmcft.

Presently, the total percentage of water storage in all four reservoirs is just 49 percent. The percentage, however, does not include the dead storage level at which the water is unusable for human consumption.

While the gross storage level of Harangi Dam in Kodagu District is 8.50 tmcft, the level on Nov. 22 was 4.58 tmcft (54 percent) while last year, as of the same date, the storage level was at 4.46 tmcft. The gross storage level of KRS Dam in Mandya District is 49.45 tmcft, the level on Nov. 22 was 22.33 tmcft (45 percent) while last year, as of the same date, the storage level was at 45.58 tmcft.

The gross storage level of Hemavathi Dam in Hassan District is 37.10 tmcft, the level on Nov. 22 was 15.88 tmcft (43 percent) while last year, as of the same date, the storage level was at 32.12 tmcft. The gross storage level of Kabini Dam at H.D. Kote in Mysuru District is 19.52 tmcft, the level on Nov. 22 was 13.76 tmcft (71 percent) while last year, as of the same date, the storage level was at 15.29 tmcft.

As of Nov. 22, the inflow to Harangi Dam is 44 cusecs while the outflow is 2,100 cusecs while Hemavathi Dam has an inflow of 339 cusecs and an outflow of 1,300 cusecs. In contrast, KRS Dam has an inflow of 1,572 cusecs and an outflow of 4,141 cusecs. Kabini Dam has an inflow of 148 cusecs while an outflow of 1,900 cusecs recorded on Nov. 22. 

Marked deficit rainfall in Kodagu, Mysuru and Hassan regions have contributed to the lower storage levels in the four dams of the Cauvery basin. From June 1 to Sept. 30 (Southwest Monsoon), the South Interior Karnataka got 271 mm of rainfall as against a normal rainfall of 369 mm, marking a deficit of 26 percent.

From Oct. 1 to Nov. 22 (Northeast Monsoon), the South Interior Karnataka got 124 mm rainfall as against a normal rainfall of 182 mm, resulting in a deficit of 32 percent. From Jan. 1, 2023, to Nov. 22, the South Interior Karnataka received 558 mm rainfall as against a normal rainfall of 694 mm resulting in a deficit of 20 percent.

From June 1, 2023, to Nov. 22, the region received 395 mm as against a normal rainfall of 551 mm resulting in a 28  percent deficit.