After a torrid and unusually hot summer, the monsoon rains could not have been more welcome when they set in over Kerala at the end of May. But the progress of the rain-bearing clouds northwards was sluggish and, by the end of June, the nationwide rainfall deficit stood at 16 per cent. After last year's bad drought, there were some jitters over whether the monsoon might slip once again into the red. In its first seasonal forecast issued in April, the India Meteorological Department (IMD) had predicted that it would be a ‘normal' monsoon with a deficit of only two per cent. In a normal monsoon, the nationwide rainfall is within 10 per cent of the long-period average. An updated forecast issued in late June said that the monsoon could finish with a slight surplus of two per cent, and it mainly relied on the “very high probability” of a La Nina developing in the Pacific Ocean. A La Nina, characterised by the waters of the equatorial eastern and central Pacific being cooler than usual, is beneficial for the Indian monsoon. That is indeed what has happened. From the third week of July, the rains have been bountiful. With the exception of eastern and north-eastern India, which currently shows an 18 per cent deficit, the rest of the country has received above-average rain.

Year after year, floods create havoc in some place or other during the monsoon. This year the focus has been on Pakistan where the rising waters have caused millions to flee their homes with livestock and destroyed crops across the country. Although India was spared disaster on such a scale, reports of heavy rains and consequent flooding have come in from many places. The ravages wrought by torrential downpour can be compounded by water being suddenly released from dams and reservoirs that are rapidly filling up. Of course, it is only when the water rises alarmingly that it is released. However, scientific methods are now available to monitor rainfall as it occurs and then estimate the amount of the water that will in due course flow into a reservoir. These methods aid better management of the reservoir, helping to decide in advance when and by how much various sluice gates need to be opened. Such real-time monitoring and management systems are expensive and need extensive customisation. Moreover to minimise flooding downstream they must be put in place for all reservoirs and dams in a river basin. With the grim possibility that climate change could make extreme rainfall a more frequent occurrence, the government needs to take all possible steps to limit flooding and the damage it causes.


Uttar Pradesh battles flood fury as 68 more dieSeptember 24, 2010

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