CHENNAI: With 79% of Tamil Nadu’s irrigation tanks either dry or holding water at less than a quarter of their capacity, the northeast monsoon commenced on October 15 amid concerns over replenishing water sources and uncertainty brought in by El Nino conditions. The Regional Meteorological Centre (RMC), Chennai, has forecast widespread rain, with heavy to very heavy rain likely in several districts.
As per Water Resources Department data available with TNIE, 4,734 of the state’s 14,141 irrigation tanks were dry on Thursday, while another 6,385 held just 1% to 25% of their capacity. Storage in the state’s 90 reservoirs stood at 60.756 thousand million cubic feet (TMC), just 27.1% of their combined capacity.
The situation is particularly stark in Madurai, where 1,148 of 1,340 tanks were dry, and Thanjavur, which had 535 dry tanks out of 641. In Tiruvallur, 295 of 578 tanks were dry, while another 160 held only 1% to 25% of capacity. In contrast, Kanniyakumari had 411 full tanks.
V R Durai, director of the area cyclone warning centre, said the southwest monsoon had recorded a 21% rainfall deficit during the season. “But, northeast monsoon rainfall will be normal with regional variations,” he said.
The IMD forecast heavy to very heavy rain at isolated places in the Nilgiris, Coimbatore, Theni, Dindigul, Tenkasi and Madurai. Chennai is likely to receive moderate rain with thunderstorms and lightning on October 16.
Expectations with rain
The Tamil Nadu government’s Expert Advisory Committee has cautioned against assuming that El Niño will necessarily cause deficient northeast monsoon rainfall.
K J Ramesh, former director general of meteorology, told TNIE that above-normal seasonal rainfall might not mean more rainy days. “The number of rainy days will be less compared to earlier, but rainfall in the fewer days will be more intense,” he said, attributing the shift to climate change. “Climate change has already altered the rainfall pattern. We are seeing short-duration, high-intensity precipitation,” he said.
Ramesh added that the benefits would depend on whether rain fell over reservoir and tank catchments. “Where it rains and when it rains” would determine whether reservoirs, tanks and aquifers benefited.