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The 1962 Irrigation Commission defined a drought-prone area as one which receives less than 10 cm rainfall and even three-fourths of this is not received in 20 per cent or more of the years under consideration; or an area in which 30 per cent or less of the total cropped area is irrigated.
Erratic nature of the monsoons exhibiting late onset and early withdrawals at times, dry spells occurring during the rainy seasons and a highly uneven spatial distribution of rainfall are the main causes of occurrence of droughts in India.
Different parameters can be used to identify the drought-prone areas. Here, we will discuss two such schemes.
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Three levels of intensity of droughts can be identified if the combined effect of parameters, such as rainfall intensity, periodicity of rainfall, ground water potential and agricultural production, are taken into account.
The three levels are as follows:
I. Extreme drought conditions cover 12 per cent of the total drought-prone area; these areas include western Rajasthan and Gujarat, western Uttar Pradesh, north-west Madhya Pradesh.
II. Severe drought conditions prevail over 42 per cent of the total drought-prone area; these areas are the leeward side of Maidan plateau, Rayalaseema and Telengana regions of Andhra Pradesh and Marathwada and Vidarbha regions of Maharashtra.
III. Moderate drought conditions affect 46 per cent of the total drought-prone area; these areas are Orissa, central-north Madhya Pradesh,. Chhotanagpur, Jammu and Kashmir and central- east Tamil Nadu.
The second scheme looks at the absolute spatial distribution of drought-prone areas while ignoring the intensity. The total drought-prone area in India amounts to 10.7 lakh square kilometres. On an average, one in every five years is a drought year.
The drought-prone are includes:
(i) the rectangle formed by the lines from south Saurashtra Coast to Kanpur and then to Jalandhar (6 lakh sq km); (ii) a second drought zone that occupies most of the area in the leeward side of the Sahyadris stretching eastward upto 100 km of the east coast and southward up to a line joining Tumkur (Karnataka) and Chittoor (Andhra Pradesh) (3.7 lakh sq km); (iii) certain isolated pockets (1 lakh sq km)—Coimbatore and Tirunelvelli districts of Tamil Nadu; Jhansi, Lalitpur, Banda and Mirzapur districts of Uttar Pradesh; Purulia district of West Bengal; Palamau district of Jharkhand and Kalahandi district of Orissa.
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From past experience, certain guidelines can be outlined to mitigate the harmful effects of droughts in the country.
Such a programme would include:
(i) Conjunctive use of rainwater, surface water and ground water potential;
(ii) Proper lining (i.e. protecting the sloping sides of a canal with some hard surface like big stones or concrete) of canals and channels to avoid loss of water through seepage to adjoining areas;
(iii) Development and promotion of trickle/drip irrigation and sprinklers in desert areas to conserve water and reclaim saline land;
(iv) use of appropriate plant varieties and cropping patterns for protection from drought and stress on location-specific minor irrigation works; such as anicuts, bandharas, tanks and dugwells;
(v) Expeditious completion of ongoing projects.