Tamil Nadu receives 56% more rain during southwest monsoon

The state, which has frequently suffered the vagaries of monsoon , has seen 56% increase from the normal rainfall between June 1 and August 10. The good rainfall in northern districts like Vellore until Monday brought cheer to water managers. Except Cuddalore (-8%) and Kanyakumari (-9%), almost all the districts have seen above normal rainfall.

Some ten districts recorded more than 100% rainfall than normal, with Tirupur (230%), Karur (198%) and Theni (152%) topping the high rainfall districts until Monday.


“We have not had this good southwest monsoon in the last ten years. There are multiple reasons, including upper air circulation, easterly winds combined with moisture incursion at different periods for good rainfall,” said Chennai regional meteorological centre (RMC), deputy director general, K Balachandran. Devala (The Nilgiris) and Yercaud (Salem) recorded 12cm and 10cm in the 24-hour period ending 8.30am on Monday. The weathermen, however, forecast dry weather for the next three days, while light to moderate rain is likely due to convection. “The recurrence of landslides in the ghat areas led to a shift in the wind direction, and that is one of the reasons for extremely heavy rainfall. And strong wind at 1.5 km height all along the Kerala coast led to orographic precipitation over ghat areas,” RMC Area cyclone warning centre director N Puviarasan said.

As a result, Mullaperiyar dam in Idukki district, maintained by Tamil Nadu government that supplies water to five southern districts received 4,825 cusecs (cubic feet per second) of water on Monday. The water level reached 136.25ft in the morning as against the permitted level of 142ft.

From Mullaperiyar, the state PWD withdrew 2,100 cusecs of water to Vaigai dam through four penstocks at its maximum capacity, while rain continued to lash in the water catchment areas (19mm), the highest for any reservoir maintained by the state. “Additional staff have been deputed for the dam and we are closely monitoring the situation. The storage is comfortable,” said a senior official. Bhavanisagar dam that receives inflow of 8,168 cusecs from western ghats surpassed 100ftmark on Monday and PWD has geared up to release the surplus when the level touches 102ft in a day or two. Sholayar dam is full in Parambikulam-Aliyar Project (PAP) group of dams in the western ghats. TN water supply and drainage board, that relies predominantly on the Cauvery for 1,900 million litres per day for its combined water supply schemes, hopes to maintain the supply until the northeast monsoon.