Inflow has begun trickling into Chennai’s reservoirs with the onset of the Northeast monsoon after prolonged dry weather. Heavy rainfall is expected across several districts, including Chennai, on Saturday, with intense spells likely in parts of the north and the Western Ghats districts.

The key waterbodies in Poondi, Chembarambakkam, and Red Hills, which contribute a major share of the drinking water for the city, received marginal inflow after nearly three months. The city’s five reservoirs, which includes Cholavaram and Thervoy-Kandigai, have a combined storage of 3.8 thousand million cubic feet, which is nearly 33% of their total storage capacity.

Officials of the Water Resources Department (WRD) said the reservoirs had earlier received marginal inflow in August. Sustained spells of heavy rain are required for a significant rise in storage. The tanks upstream of the Red Hills reservoir, for instance, are holding only 30% to 50% of their capacity. It will take more intense rainfall days for them to fill up and discharge surplus water to the reservoir.

Meanwhile, the Regional Meteorological Centre (RMC) has announced that the Northeast monsoon is vigorous over the State and fairly widespread rainfall covering up to 75% of the weather stations will continue till October 22. In the 24 hours ending 8.30 a.m. on Friday, Adayamadai in Kanniyakumari district received a very heavy rainfall of 18 cm. Several other south and interior parts received moderate to heavy rainfall.

The RMC has issued an orange alert to six districts as intense rainfall of up to 20.4 cm is expected across parts of north Tamil Nadu on Saturday as well. Many coastal and interior districts, including Chennai, Cuddalore, Namakkal, Karur, and Thanjavur, are likely to receive heavy rainfall of up to 11.5 cm.

The State may continue to experience an intense rainspell till October 22. The RMC has issued an orange alert as very heavy rainfall is likely in isolated places of the Western Ghats districts till October 20. North Tamil Nadu districts, such as Chennai and Tiruvallur, will also experience very heavy rainfall on October 21.

Wet weather for the next few days is expected to keep the maximum temperatures close to normal over Tamil Nadu and Puducherry.