Karnataka may have to release nearly double the stipulated 3,500 cusecs owing to dry riverbed till Biligundlu

Though the Cauvery Water Regulation Committee (CWRC) that reviewed the storage and rainfall situation in the Cauvery basin on Tuesday has directed Karnataka to release 3,500 cusecs of water a day to Tamil Nadu for 15 days, experts say that Karnataka may have to actually release one-and-half to two times more than this quantum.

“This is because the CWRC has said Karnataka has to ensure flow of 3,500 cusecs a day at the Biligundlu measuring gauge located on the inter-State border. But the riverbed and banks enroute Biligundlu are dry now. Besides, the State also has to account for groundwater levels and channel losses, riverbed and bank storages. In other words, a significant percentage of water released from either KRS or Kabini reservoirs will be lost by the time it reaches Biligundlu measuring gauge,” observed an hydrology expert.

Hence, to realise the stipulated flow of 3,500 cusecs at Biligundlu, Karnataka may have to release approximately 6,000 to 7,000 cusecs a day (one-and-half to two times of the required flow) from KRS and Kabini reservoirs, observed an official.

The official data on storage situation, as on July 28, shows that 1,745 cusecs of water are being released from the KRS as against the inflow of 2,552 cusecs; while 300 cusecs of water are being released from Kabini as against the inflows of 3,594 cusecs. A total of 2,045 cusecs of water are being released to Tamil Nadu as of now from these two reservoirs although the quantum may deplete by the time it reaches Biligundlu.

As per the official data, the cumulative storage in all four reservoirs of Karnataka’s Cauvery basin accounts for only 55% of their full capacity. As against the full capacity of 114.57 tmcft, the present storage accounted for only 63.23 tmcft. The storage stood at 108.68 tmcft during the corresponding period last year. The storage in KRS is particularly a cause of concern as it stands at 34% of its capacity.

Karnataka relies heavily on the southwest monsoon as it accounts for 73% to 75% of the State’s annual rainfall. But this time, the monsoon is weak and the State is facing a rainfall deficit of about 35%. The Kodagu region that forms the biggest catchment area for the Cauvery, which takes its origin in this hilly district, too is facing a rainfall shortage of 45%.

On Water Resources Minister K. Ramalinga Reddy’s statement that the State would consider filing an appeal against the CWRC order before the Cauvery Water Management Authority, an expert said that Karnataka may place before this authority the prevailing hydrological facts including severe rainfall deficit across the Cauvery basin, poor inflow to reservoirs as well as critically low storage levels. The State is also likely to highlight the declining groundwater levels and unsaturated riverbeds besides the overriding priority of handling drinking water requirements, said the expert.