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DROUGHT
Drought is a temporary reduction in water or moisture availability significantly below the normal or expected amount for a specific period. This condition occurs either due to inadequacy of rainfall, or lack or irrigation facilities, under-exploitation or deficient availability for meeting the normal crop requirements in the context of the agro-climatic conditions prevailing in any particular area.
Types of Drought
There are three types of drought
- Meteorological Drought describes a situation where there is a reduction in rainfall for a specific period (days, months, season or years) below a specific amount (long term average for a specific time).
- Hydrological Drought involves a reduction in water resources (stream flow, lake level, ground water, underground aquifers) below a specified level for a given period of time
- Agricultural Drought is the impact of meteorological/hydrological drought on crop yield.
Moisture Index in Different climatic Zones in India
Moisture Index |
Climate Zone |
Percent Area |
-66.7 |
Arid |
19.6 |
-66.7 to -33.3 |
Semi-arid |
37 |
-33.2 to 0 |
Dry sub-humid |
21.1 |
0 to +20 |
Moist sub- humid |
10.2 |
+20.1 to 99.9 |
Humid |
7.8 |
100 |
Pre-humid |
8.3 |
Drought Management
The strategy for this management is basically threefold.
- Close monitoring of the emerging drought scenario so as develop an advance warning system
- Relief measures required for providing immediate succor to the affected population and the upkeep of the cattle wealth, and if possible to integrate it with long term objectives and
- Hammering out an alternative crop strategy for maximum possible retrieval of the Kharif crop and a better ensuing Rabi crop.
Since drought prediction methods are at a very nascent stage, IMD has made efforts to provide a long range forecast of monsoon rainfall. In 1988, a parametric power regression model was developed on the basis of global and regional meteorological and oceanic parameters (physically related monsoon and rainfall) for estimating the monsoon rainfall of India. The model is successful in estimating the correct nature of monsoon and can be utilized for drought mitigation planning. IMD carries out rainfall monitoring unto district level on a real time basis. All this helps in estimating the drought conditions over any particular region
Warning and Dissemination
- There is a "Weather- Watch-Group" in the Ministry of Agriculture, which meets every week to take stock of the rainfall progress, its effects on the crops from sowing to harvesting, during the kharif season. Weekly input from IMD gives an early warning about the impending drought as and when symptoms arise in this regard and the states are warned accordingly
- The National Agricultural Drought Assessment and Management system (NADMS) is being developed by the Department of space for the Department of Agriculture and Co-operation, and is primarily based on the monitoring of vegetation status through National Oceanic and Atmospheric Administration (NOAA) Advanced Vary High Resolution (AVHR) data. The drought assessment is based on a comparative evaluation of satellite observed green vegetation cover (both area and greenness) of a district in any specific time period, with that of any similar period in previous years.
Employment Generation
Three other aspects which call for urgent attention in a drought situation are employment generation, drinking water supply and fodder availability, Generation of additional employment through Detailed planning is required to arrive at a reasonable and realistic estimate of the total labour force required so as to have a realistic picture of 'man- days' which would be required to be generated to cater to the employment needs t each group of villages. In mono-cropped areas without any other worthwhile irrigation facilities work has to be provided for almost till the onset of the next monsoon season.
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