Two-and-a-half months after the advent of southwest monsoon, an interesting scenario has emerged in the State. While 11 out of 32 districts have recorded excess rainfall, an equal number of districts has registered deficit rainfall.
Chennai and Coimbatore districts come under the excess rainfall category, whereas Tiruchi and Madurai are not that lucky as they are among those with deficit rainfall.
The remaining 10 districts have witnessed, what is called in meteorological parlance, normal rainfall with a deviation of minus or plus 19 per cent of the expected rainfall.
An analysis of districts reveals that a majority of northern districts has seen surplus rainfall whereas the situation is the opposite in the south. Chennai, Kancheepuram, Cuddalore, Villupuram and Tiruvalllur have got much more than their average rainfall up to the period ending August 18. Kanyakumari, Theni and Tirunelveli are the southern districts to get surplus rainfall.
In respect of deficit rainfall, Dindigul, Ramanathapuram, Tuticorin and Virudhunagar fall under this category besides Madurai. The State, as a whole, received 16.64 cm rainfall against the normal of 16 cm, a deviation of four per cent, which is considered normal. Y.E.A. Raj, Deputy Director General of Meteorology, points out that till about a week ago, Tamil Nadu’s rainfall was close to deficit with a deviation of minus 18 or 19 per cent. But, the monsoon picked up rapidly.
A significant aspect of the rainfall pattern this time is that of the composite Thanjavur district, Nagapattinam has registered excess rainfall and Thanjauvur and Tiruvarur districts have recorded normal rainfall.
With the Mettur dam’s water level remaining more or less at full level, a fairly good amount of rainfall in the Cauvery delta during the southwest monsoon brightens the prospects of a bumper samba crop.
As both Kancheepuram and Tiruvallur districts along with Chennai have seen surplus rainfall, people in the three districts, one among the populous belts of the State, may not have much problem with regard to drinking water supply at least for the next few months.
What should be of concern to the authorities is that the districts of Ariyalur, Dharmapuri and Krishnagiri, conventionally considered less developed, have experienced deficit rainfall.
However, one saving grace for Dharmapuri and Krishnagiri is that no problem of drinking water supply is anticipated as plenty of water continues to flow through the Cauvery this year and providing assured supply for the newly-commissioned Hogenakkal Water Supply Project.
Though it is during the northeast monsoon (October-December) that the State gets benefitted hugely, the current season – southwest monsoon (June-September) – does play a role in ensuring a relatively-comfortable level of groundwater table, before the onset of the northeast monsoon.