T.N. may be heading towards a water crisis, unless northeast monsoon comes to the rescue

A weak Northeast monsoon would reduce the rain feeding Tamil Nadu’s reservoirs, rivers and farmland. That matters because stored water supports irrigation during the rice-growing samba-thaladi season. If supplies remain low, authorities may be unable to sustain releases to farmers, especially in the Cauvery delta.

Mettur Dam illustrates the pressure. It has roughly 23 tmcft, but the article says that is enough to maintain releases to delta farmers for only about a week. Outside the delta, paddy coverage is already 1.3 lakh hectares below last year’s level. Direct sowing has risen from 39% to 57%, a method used when water is scarce.

The risk is therefore twofold. Farmers may cultivate less land, while existing crops may receive inadequate irrigation. Tamil Nadu produced 77.5 lakh tonnes of rice in 2025-26, already below its earlier high. More November rain could improve storage and protect production; continued weakness could deepen the shortfall.

The article does not define the Northeast monsoon. In standard usage, it is the seasonal rainfall period affecting southern India mainly from October through December, when winds bring rain to Tamil Nadu. It is especially important because Tamil Nadu receives a large share of its yearly rainfall during this season.

The article records about 240 mm of rain so far, against an anticipated 236 mm. TNAU forecast 438 mm for the full monsoon, close to the 434 mm normal. The State needs at least another 260 mm to reach a comfortable position. November is expected to provide most of that remaining rain.

This rainfall replenishes reservoirs and supports river flows and farm irrigation. December ordinarily provides only about 20% of the monsoon’s total rainfall. Therefore, if November does not deliver, there is less time and seasonal rainfall left to refill supplies, protect paddy and sustain releases to farmers.

Tamil Nadu’s 15 major irrigation reservoirs currently contain about one-third of their combined storage capacity. This is a measure of how much water is available for irrigation, not simply how much rain has fallen. Low storage can limit releases to farms even when rainfall totals appear close to normal.

The contrast with last year is stark. During the corresponding period, the reservoirs held around 92% of their combined capacity. Now, aggregate storage is roughly a third. Mettur Dam, the State’s largest, contains about 23 tmcft, but that amount can support sustained Cauvery delta releases for only about a week.

The low storage reflects the immediate water-management problem. Tamil Nadu needs additional Northeast monsoon rain, particularly in November, to improve supplies. Without it, authorities face pressure to ration releases, while farmers may reduce cultivation or rely more heavily on direct sowing. Rice production could consequently weaken.

Mettur is Tamil Nadu’s largest dam and a major source for farmers in the Cauvery delta. Its roughly 23 tmcft of stored water sounds substantial, but the article says it is hardly enough to maintain sustained releases beyond a week. That makes the reservoir’s level a direct concern for the current paddy season.

The key mechanism is continued demand. Delta farmers need regular water releases to support crops across the cultivated area. A limited stock must serve those releases over time, rather than being used once. If inflows do not replenish the dam, extending releases becomes difficult and authorities may have to restrict water supplied to farms.

The situation is especially sensitive because farmers have planted about 3.62 lakh hectares of samba-thaladi paddy in the delta region. More Northeast monsoon rain could add water and prolong releases. Without it, crops face greater irrigation uncertainty, and rice production could fall.

Tamil Nadu has received around 240 mm during the Northeast monsoon, slightly above the 236 mm anticipated so far. Yet the State needs at least another 260 mm to be considered comfortable. This threshold matters because rainfall helps replenish reservoirs and support irrigation for the rice crop.

November is the crucial month because most of the remaining rainfall is expected then. The article notes that December ordinarily yields only about 20% of the monsoon’s total rainfall. For example, a delayed recovery in December would normally provide much less rain than a strong November.

The forecast context is mixed but close to normal. TNAU predicted 438 mm for the entire season, against a normal 434 mm, while actual rainfall so far is around 240 mm. If November supplies the needed rain, storage and farm releases may improve. If not, water stress could continue through the crop season.

Tamil Nadu asked Karnataka to release around 20.7 tmcft to protect the Cauvery delta crop. That request included an estimated backlog of about 16.9 tmcft. The demand was made at meetings of the Cauvery Water Regulation Committee and the Cauvery Water Management Authority.

The Authority did not accept the full request. It ratified the Committee’s recommendation that Karnataka release 3.88 tmcft to Tamil Nadu. The release was to be made at 3,000 cubic feet per second for 15 days, beginning Saturday, November 7, 2026.

The difference is substantial. Tamil Nadu sought water to address both immediate crop needs and the accumulated shortfall, while the approved quantity was much smaller. The release may support delta farmers temporarily, but the article indicates that continued protection of the crop also depends on Northeast monsoon rainfall and available reservoir storage.

In an agricultural region, monsoon rainfall is the starting point. Rain becomes river flow and reservoir storage, creating water that authorities can release for farms. Those releases determine whether farmers can plant, maintain and harvest water-intensive crops such as paddy. Weak rainfall can therefore affect both acreage and yields.

Tamil Nadu shows this chain clearly. Major reservoirs now hold about a third of capacity, compared with 92% last year. Mettur has roughly 23 tmcft, enough for only about a week of sustained delta releases. Farmers responded to water uncertainty: direct sowing accounts for about 57% of paddy coverage, compared with 39% previously.

The final effect appears in production. Non-delta paddy coverage is 1.3 lakh hectares below last year, and rice output in 2025-26 was 77.5 lakh tonnes. More rain, reservoir storage and river water could support cultivation. Continued shortages could limit irrigation and lower future production.