The water-level in the Krishnaraja Sagar (KRS) near Srirangapatna has gone down majorly.
The water-level was 75.8 ft as against the full reservoir level of 124.80 ft at 6 a.m. on Thursday.
According to officials of Cauvery Neeravari Nigam Ltd. (CNNL) and the Irrigation Department, concerns about drinking water scarcity in Bangalore, Mysore, Mandya and Ramanagaram are expected to be aggravated in the coming days.
Compared to the previous year, the water-level in KRS, which supplies water to several districts in Karnataka, Tamil Nadu and Puducherry, has fallen more this year.
The water-level in KRS stood at 75.8 ft on Thursday morning as against 110.43 ft on the same day in 2012. While the rate of inflow was at 385 cusecs, the outflow stood at 551 cusecs at 6 a.m. on Thursday.
The storage is 7.01 tmcft as against 21 tmcft during the same period last year, officials told The Hindu here on Thursday.
Once the water-level falls below 74 ft, it will be difficult to ensure drinking water supply to various cities.
Water can be drawn from the reservoir up to a depth of 60 ft. Once the water-level falls below 60 ft, water cannot be released, the officials said.
In that case, water may be released from Harangi and Hemavathi to KRS to meet drinking water needs, the officials said.
The Irrigation Department had stopped discharging water into Cauvery dependent canals from January 1.