Tamil Nadu may face an acute water shortage next summer if one were to go by the present storage of all the important reservoirs across the State.
In sharp contrast to the position exactly a year ago when the reservoirs either had comfortable storage or were close to the brim, the water sources now have an extremely poor storage. Not a single reservoir has storage that is two-thirds of the capacity. The Krishnagiri reservoir, whose capacity is about 1.63 thousand million cubic feet (tmc ft), is the only dam in the State with over 50 per cent storage. As on date, its storage is around 0.97 tmc ft. In absolute terms, Mettur has the highest storage with around 11.6 TMC. But, its storage is hardly 12 per cent of the capacity of 93.47 tmc ft.
The failure of the northeast monsoon is cited as the primary factor for the position of the reservoirs. The latest spell of rain due to Cyclone Vardah has only brought down the State’s deficit from 66 per cent to 61 per cent, says S. Balachandran, Director in the Meteorological Department. As on date, Tamil Nadu should have realised 40 cm rain, whereas it has got only 15.96 cm. In 2015, for the period up to December 9, the State got about 64 cm with an excess of 63 per cent.
Even though some areas in and around Chennai received very high rainfall a few days ago, this did not push up the water level of Chennai’s reservoirs substantially. For instance, on Wednesday morning, the Chembarampakkam tank, which was at the centre of the public attention last year, registered an inflow of about 1,600 cubic feet per second (cusecs), but its storage was barely 18 per cent of the capacity of 3.6 tmc ft.
An official in the Public Works Department says that going by the rainfall pattern in the past, it is “very, very unlikely” that even if rains occur in the coming weeks, they will neutralise the State’s deficit. The monsoon is expected to last till the end of this month. Mr. Balachandran adds that for the next three or four days, no cyclonic system is in the offing.
Once the monsoon is over, there will be enormous pressure on groundwater resources, which are already under stress, to meet the drinking water and irrigation requirements, the PWD official adds.
