Drought in India: Its impact and mitigation strategies A review

Abstract

Drought is temporary reduction in water or moisture availability significantly below the normal amount for a spe- cific period. It is a climatic anomaly characterized by deficient supply of moisture resulting either from sub-normal rainfall, erratic rainfall distribution, higher water need or a combination of all the 3 factors. Droughts, in general, are extreme hydrologic events causing acute water shortages which persist long enough to trigger detrimental effects on human, vegetation, animals and ecosystem over a considerable area. To a meteorologist, drought is the ab- sence of rain, while to the agriculturist it is the deficiency of soil moisture in the crop root zone to support crop growth and productivity. Based on the criteria, concept of its utilization and different schools of thought, drought is broadly categorized into meteorological drought, hydrological drought, agricultural drought and socio-economic drought. In rainfed areas, drylands are more prone to drought. Since last one decade of 21st Century, it has been observed that monsoon rains are deviating much from its predictions and the states/regions which never experi- ence such a natural calamity comes under mild to acute droughtprone regions. In cases of field crops and other vegetation, it creates moisture-stress conditions when the amount of water needed for evapotranspiration exceeds the total amount of moisture available in soil. To define, drought is taken to have occurred over an area where the annual average rainfall is less than 5075% of the normal southwest (SW) monsoon rains. Delayed onset of S W monsoon rains or early receding of monsoon rains towards halfway of the season or long gaps between 2 heavy and effective rains during rainy season are the general phenomenon of agricultural drought in India. The In- dia Meteorological Department (IMD) generally predicts the monsoon status (weak or normal) 34 months before for each state/region. In this article, the nature, impacts of recent agricultural droughts in India and mitigation strat- egies are reviewed.