Tamil Nadu's 90 reservoirs collectively held just 75.7 thousand-million cubic feet (TMC) of water as of 3 November 2026, amounting to only 33.7 per cent of their combined storage capacity — even as the northeast monsoon intensified and spread rainfall across the state. The figures, cited by Water Resources Department officials, underscore a deepening water availability concern heading into the dry months.

The Storage Picture

Of the state's 90 reservoirs, only three have reached full capacity. A significant 43 reservoirs hold less than 25 per cent of their storage, while another 24 are below the 50 per cent mark. The stark distribution highlights how unevenly the monsoon's benefits have been captured across different catchment areas.

A handful of reservoirs have bucked the trend. Gundar in Tenkasi, Mambazhathuraiyar in Kanniyakumari, Sothuparai in Theni, Sastha Koil and Kullursandai in Virudhunagar, and Varadhamanadhi in Dindigul have reportedly crossed 95 per cent of their storage capacity. The Peruvaripallam reservoir under the Coimbatore Water Resources Department has also recorded storage exceeding 95 per cent.

Why Rain Is Not Filling the Reservoirs

Water Resources Department officials attribute the persistently low levels primarily to a prolonged dry spell and intense heat that left reservoir beds severely parched before the monsoon arrived. As storage fell, large stretches of reservoir floors became exposed; sustained high temperatures then dried the accumulated silt, producing extensive cracking across the beds.

'The rainfall currently being received is being absorbed rapidly by the dried-up reservoir beds. Consequently, there has been no significant increase in water storage,' an official associated with the Dam Protection Movement explained. He noted that sustained rainfall would first need to replenish soil moisture and restore groundwater conditions before meaningful surface-water accumulation could occur.

The same official cited the El Niño weather phenomenon as a key upstream factor, arguing it contributed to deficient southwest monsoon rainfall earlier in the year, triggering the sharp decline in reservoir levels that the northeast monsoon has so far been unable to reverse.

Geographic Spread of the Monsoon

Districts along the Western Ghats have received northeast monsoon showers over the past several days, and precipitation has only recently become widespread across northern Tamil Nadu. Officials acknowledge, however, that the recent spread has yet to translate into a statistically meaningful improvement in aggregate storage.

What Authorities Are Watching

State officials are closely monitoring rainfall patterns and reservoir inflows to assess whether storage will recover in the weeks ahead. The uneven distribution across the state's reservoirs, they note, reinforces the need for sustained and well-distributed monsoon rainfall to restore water reserves before the onset of summer. The situation will remain critical unless catchment areas across multiple districts receive consistent precipitation over the coming weeks.