What constitutes a drought

Print edition : February 03, 2017

Korai grass choking the Periya canal of the Thirumeni lake at Vallur in Tiruvarur district. Photo: B.Velankanni Raj

THE Government of India’s Manual for Drought Management recommends that rainfall deficiency, the extent of area sown, normalised difference vegetation index and moisture adequacy index are “the four standard monitoring tools” that can be applied in combination to declare an administrative unit drought-affected. Since information on these indicators is available at the level of taluk/tehsil/block, drought may be declared by a State government at the level of these administrative units on the basis of observed deficiencies, the manual says. At least three indicators can be considered for drought declaration but the most important criterion is rainfall deficiency.

A State government can consider declaring a drought if the total rainfall for the State’s entire duration of the rainy season from June to September (the south-west monsoon) or from October to December (the north-east monsoon) is less than 75 per cent of the average rainfall for the season and there is an adverse impact on vegetation and soil moisture, the manual says. The government can consider declaring a drought if, along with other indicators, the total area sown by the end of July/August is less than 50 per cent of the total cultivable area. The declaration of drought could be linked with other indicators if the area of sowing was less than 50 per cent of the cultivable area by the end of November/December .

Moisture adequacy index (MAI) values “are critical to ascertain an agricultural drought”, says the manual. The MAI values should be applied in conjunction with other indicators such as rainfall figures, area under sowing, and so on.

Other factors that a government should consider for declaring a drought are the drinking water supply situation, the extent of fodder supply and its prevailing price compared with normal price; unusual movement of labour in search of employment; the prevailing agricultural and non-agricultural wages compared with normal times; and supply of foodgrains and the prices of essential commodities.

“The State government is responsible for declaring a drought,” the manual says. It is necessary to declare a drought through a formal notification for the response measures to begin, it adds. Collectors can notify a drought only after the State government declares it all over the State or parts of it. States that receive rain from the south-west monsoon should declare a drought in October. In the case of States that receive rain from the north-east monsoon, the drought declaration should be done in January. If the situation warrants, it can be done earlier.

T.S. Subramanian

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