New Delhi: A plea citing drought, shrinking reservoir inflows and fears over drinking water supplies failed to sway the Cauvery Water Management Authority (CWMA) on Thursday, as the statutory body directed Karnataka to continue releasing Cauvery water to Tamil Nadu in line with the existing order.

The Authority upheld the Cauvery Water Regulation Committee's (CWRC) July 28 directive requiring Karnataka to release 3,500 cusecs of water per day for 15 days, dealing a significant setback to the State, which had sought a two-week suspension of the order until the hydrological situation became clearer.

Arguing its case before the Authority, Karnataka said it was grappling with severe hydrological distress, pointing out that cumulative inflows into its four Cauvery basin reservoirs were 65.65 per cent below the 30-year average because of the impact of the super El Nino.

The State maintained that an immediate review of rainfall and reservoir levels after another fortnight would present a more accurate picture before any decision on water sharing.

Karnataka also contended that Tamil Nadu enjoys what it described as a 'dual advantage', receiving water from Karnataka during the southwest monsoon while also benefiting from the northeast monsoon later in the year. It further argued that Tamil Nadu already has substantial carryover storage from water released earlier.

The State warned that although the CWRC had ordered a release of 3,500 cusecs daily, transmission losses along the dry riverbed up to the Biligundlu inter-State gauging station could force it to release nearly 7,000 cusecs to ensure the mandated quantity reaches the measuring point.

It also reiterated that at least 40 tmcft of water is required to safeguard Karnataka's drinking water needs.

Tamil Nadu, meanwhile, pressed for a larger allocation, urging the CWMA to direct Karnataka to release 9.45 tmcft over the next 15 days under the distress-sharing formula, equivalent to 7,000 cusecs a day, citing severe hydrological stress in its own basin.

After reviewing reservoir conditions, the CWMA observed that inflows into Karnataka's reservoirs had improved and noted that the Kabini reservoir was nearing its full storage level.

It further assessed that Karnataka's reservoirs are likely to receive at least 15 tmcft of water over the next 15 days and concluded that releasing 4.5 tmcft would not adversely affect the State's drinking water requirements.

Following the decision, Karnataka Deputy Chief Minister D.K. Shivakumar announced that an all-party meeting would be held in Bengaluru on Sunday to deliberate on the State's next course of action.

Former Chief Ministers, Members of Parliament and legislators from the Cauvery basin will be invited for consultations.

Government sources said Karnataka is also expected to seek legal opinion before deciding its next move, with protests by farmers in the Cauvery basin adding to the pressure on the State government over any further release of water to Tamil Nadu.