Vardah flattens hopes on lakes

Going by the present scenario, the Chennai Metro Water Supply and Sewerage Board (CMWSSB) supplies 830 million litres per day (MLD) of water from various sources. The two desalination plants in Nemmeli and Minjur yield 200 MLD, according to officials. 

However, the four reservoirs in Chennai region are the main drinking water sources. Poondi, Chembarambakkam, Cholavaram and Red Hills play the main role in mitigating water scarcity. Unfortunately, these reservoirs at present hardly have 1.96 tmc of water against total capacity of 11.057 tmc, while the average requirement for the city is about 1.2 tmc per month. 

The other major water sources include the Veeranam lake in Cuddalore district, which has capacity of 1,465 million cubic feet. Water from the Cauvery, released from the Mettur dam through Kollidam and lower Anicut flow into the Veeranam lake. However, since the lake has only 425 mcft currently, Metro Water department will find it difficult to draw water after 75 days. The Veeranam lake can supply 180 MLD of water. 

As for water from the Krishna river, the Andhra Pradesh government is required to release 12 tmc of water every year in two spells to the Poondi reservoir. So far this year, PWD has received only 985 million cubic feet (1 tmc=1,000 million cubic feet). If the AP government had released the 12 tmc of water, Metro Water could have supplied drinking water to the city for nearly 10 months.

In a major setback, the AP government stopped releasing water from Kandaleru reservoir. “We were informed by our AP counterparts that they had stopped releasing water. However, we were assured that the water will be released after three to four days,” said a senior engineer, PWD (WRD).

Whenever the northeast monsoon fails, Metro Water mulls other options including tapping ground water resources. Sources said, “The officials are planning to tap water from around 300 private agriculture wells. This source would supply around 50 MLD.” Metro Water would also identify private borewells in Panruti-Sethiathopu stretch, as was done in the previous drought-hit years.

“You can’t jump to a conclusion that northeast monsoon completely failed and there is still time. The existing water level in the lakes is enough to meet the drinking water needs for the next two to three months, after which we will explore the possibilities to draw water from other sources,” said a top CMWSSB official.