Thursday, February 19, 2015

Drought

A drought is a situation caused due to an extended period of rain deficiency. Droughts can affect large countries or a small village. A drought normally occurs when a region receives below average rainfall. It can have substantial impact on the ecosystem and agriculture of the affected region. Droughts can persist for a long period of time, even a short intense drought can cause significant damage and harm to the local communities. An area is declared by the government as drought affected when rainfall is less than 25% of the average annual rainfall for that area. It is declared as severely drought affected when deviation of rainfall from normal is more than 50%. Droughts are of three types:
1. Meteorological drought is when rainfall is 25% less than average
2. Agricultural drought when rainfall is not conducive to the growth of monsoon crop
3. Hydrological drought when water bodies dry up in surface and in aquifers under the surface.

In India, the western parts of Odhisha, Madhya Pradesh, Jharkhand, Chhattisgarh, Western Rajasthan, regions of Andhra Pradesh bordering Odhisha, Madhya Pradesh, Parts of Maharashtra and western West Bengal are prone to recurrent droughts.

Drought is a slow onset disaster; hence it is predictable. A few tools to predict droughts are: satellite imageries, rainfall data, increase in cost of food in local market, migration of able bodied men and overlay of GIS map and grid population map. Government and Non government agencies use such data to plan appropriate response to mitigate the effects of drought.


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