DROUGHTS
Rain is unpredictable in most of the arid regions of the world. Such areas face acute scarcity of drinking water. Needless to say about the water shortage for irrigation and industrial requirements in such places. Drought is an unpredictable climatic condition and may occur due to the failure of one or more monsoons. It varies in frequency in different parts of our country. The life of people, especially the farmers, in arid regions is very difficult as they have no steady income due to frequent droughts. This is especially true in our country because most of the Indian farmers are depending on rain for their water requirements. The scarcity of water during drought years indirectly affects the industries and domestic life also.
All types of droughts originate from the deficiency of precipitation. Precipitation refers to condensation of atmospheric water vapor that falls under gravity. The main forms of precipitations are drizzle, rain, sleet, snow, graupel and hail. Drought result from an unusual weather pattern. If the weather pattern persists for a few to several weeks, it is said to be a short-term drought. However, if precipitation remains well below average for several months to years, the drought is considered to be long-term.
Droughts are classified into four different kinds as follows.
1. Meteorological drought - Deficit in precipitation that is unusually extreme and prolonged.
2. Agricultural drought - Deficit in soil moisture that affects plant growth and productivity.
3. Hydrological drought - Condition in which stream discharges, wetland and water-table decline to unusually lower levels.
4. Operational drought - Condition when water supply is significantly below demand such that water supply should be reduced or water management must be changed.
When meteorological drought occurs, the after-effects cascade sequentially to the other three types of droughts. On the other hand, when the meteorological drought ends, the soil moisture gets restored, and then restoring other hydrological stock within the system and finally increases the balance in reservoirs.
Though it is not possible to prevent the failure of the monsoon, good environmental management can reduce its ill effects. Several preventive measures can be taken to minimise the serious impacts of droughts on people's lives. Conservation as well as judicious use of water during times of good monsoon will help to mitigate the difficulties of droughts to a great extent.
One of the factors that aggravate the effect of drought is deforestation. Once hill slopes are denuded of forest cover, the rainwater rushes down the rivers and is lost very fast. Forest cover protects and holds the water falling in the area permitting it to seep into the ground. This process charges the underground storage of water in natural aquifers. If water from the underground stores is overused, the water table will drop. Therefore, scientific management of soil and water coupled with afforestation are long-term measures helpful to reduce the impact of droughts.
A dry season is characterized as "a time of unusually dry weather conditions adequately drawn out for the absence of water to cause serious hydrologic irregularity in the impacted region." - Glossary of Meteorology (1959).
In more clear terms, a dry spell is a time of uncommonly persistant dry climate that perseveres to the point of creating difficult issues, for example, crop harm or potentially water supply deficiencies. The seriousness of the dry spell relies on the level of dampness lack, the length, and the size of the impacted region.
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