Not much benefit from last week’s cyclonic system

T. Ramakrishnan

Chennai recorded a mere 2 cm rainfall

CHENNAI: Less rainfall recorded by the city’s reservoirs so far during this year’s north-east monsoon (October-December) has made several citizens wonder whether the monsoon will eventually turn out to be a failure.

Break in dry spell

Though last week’s cyclonic system over the Bay of Bengal broke the prolonged dry spell over Chennai and neighbouring districts, there was not much rainfall.

In the week ending Thursday, Chennai recorded a mere 2 cm rainfall against the normal 6.5 cm.

Similarly, Tiruvallur district, where the city’s three reservoirs, Red Hills, Cholavaram and Satyamurti Sagar at Poondi, are located, registered half of what it should have received. Against the normal rainfall of 6 cm, it recorded 3 cm.

Between October and December the three reservoirs, on an average, record 73 cm, going by rainfall data from 1978 to 2007. This accounts for nearly 60 per cent of the total annual rainfall of 126 cm. In the last 30 years, the highest amount of rainfall recorded in November was in 1997. Then, the reservoirs received 95 cm. This was followed by 60 cm in 1991 and 55 cm in 1979. Last year, the reservoirs recorded 12 cm.

Acknowledging that the best part of the monsoon is over, an official of the Meteorological Department, however, says there are chances for some more rain spells over the State. The official points to the continued positive phase of southern oscillation (SO), the air pressure difference between Tahiti in the Pacific and Darwin in northern Australia.

Besides, water managers do not anticipate any problem for sustaining the drinking water supply at the present level as the State continues to receive the Krishna waters from Andhra Pradesh.

An official of the Water Resources department says the Kandaleru reservoir, the terminal storage point in the neighbouring State, has a storage of 28 thousand million cubic feet.

There will be no problem for continuing the release to Chennai. Since September 20 (when the realisation of the Krishna waters began), the State received about 3.5 tmcft.

Though the inter-State agreement provides for the supply till October, Andhra Pradesh has agreed to continue the release in view of the comfortable storage.

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