Water releases from Mettur dam for Cauvery delta irrigation are set to be suspended on Thursday, 16 October 2026, as Tamil Nadu's government-mandated 45-day supply period draws to a close — with reservoir levels down nearly 32 feet and inflows critically low, leaving delta farmers in an anxious wait.

How the Supply Period Unfolded

Chief Minister Vijay opened Mettur dam for delta irrigation on 1 September, weeks behind the traditional date of 12 June, after an inadequate southwest monsoon cast doubt on whether releases could be sustained at all this year. The delayed opening came with a firm commitment of 45 days of irrigation supply. As that window closes, the dam's storage tells the story of the strain: the water level has fallen from 91 feet on 1 September to 59.13 feet by Wednesday evening — a drop of nearly 32 feet in six weeks.

Inflows vs Outflows: A Widening Gap

The reservoir's depletion reflects a persistent mismatch between what is flowing in and what is being discharged downstream. Inflows stood at just 696 cubic feet per second (cusecs) on Wednesday — far below the volumes being released. Peak irrigation releases had touched 15,000 cusecs during the supply period; by Wednesday evening, the government had already stepped down releases from 12,000 cusecs to 10,000 cusecs as storage continued to shrink. Notably, this gradual reduction signals that authorities are already managing a soft wind-down, regardless of any formal extension announcement.

Farmers Appeal for Extension

Cultivators across the Cauvery delta — one of Tamil Nadu's most productive rice-growing belts — have formally appealed to the state government to continue releases, arguing their standing crops still require water. Their request places the government in a difficult position: weigh immediate agricultural need against the reservoir's dwindling reserves. With no significant upstream replenishment in sight, any extension of releases would further erode storage, tightening the buffer for drinking water and other uses downstream.

Northeast Monsoon: The Wildcard

The India Meteorological Department (IMD) has indicated that the northeast monsoon is expected to set in on Thursday — the same day releases are scheduled to stop. A robust onset and a rapid improvement in inflows could theoretically give the government room to extend irrigation supplies. However, meteorologists have historically cautioned that the monsoon's early days often bring limited, uneven rainfall before it fully establishes itself over Tamil Nadu. The probability of inflows recovering quickly enough to offset the current deficit remains uncertain.

What Happens Next

For Cauvery delta farmers, the immediate question is whether the government will announce an extension before Thursday's deadline — and on what terms. Any decision will hinge on a combination of factors: the pace of the northeast monsoon, revised inflow projections, and the state's assessment of minimum reservoir levels required for non-agricultural uses. Until clarity emerges, delta cultivators remain dependent on both government action and the progress of rainfall over the coming days.