Drought is a natural calamity yet conspired by humans themselves that ends up destroying the lives of the poor farmers.
Drought may be defined as an extended period- a season, a year or more of deficit rainfall relative to the statistical multi-year average for a region. It is a normal and recurrent feature of climate and may occur anywhere in the world, in all climatic zones. Its features or characteristics, of course, vary from region to region.
In simple words, drought is a period of drier-than-normal conditions that lead to water-related problems. When rainfall is below normal for weeks, months, or even years, it brings about a decline in the flow of river streams and a drop in water levels in reservoirs and wells. If dry weather persists and water supply related problems increase, the dry period can be called a “drought”.
The major drought years in India have seen large parts of the country perennially reel under recurring drought. Over half of the country is vulnerable to droughts. The “chronically drought-prone areas” receive less than 750mm of rainfall, while “drought prone areas” receive rainfall of 750-1125mm.
There are a number of classifications of drought. A permanent drought is characterised by extremely dry climate, drought vegetation and agriculture that is possible only by irrigation: seasonal drought requires crop durations to be synchronised with the rainy season; contingent drought is of irregular occurrence; and invisible drought occurs even when there is frequent rainfall, in humid regions.
Physical aspects are also used to classify drought. They may be classified into three major groups:
Meteorological drought is related to deficiencies in rainfall compared to the average mean annual rainfall in an area. There is, however, no consensus on the threshold of deficit that makes a dry spell an official drought. According to the India Meteorological department (IMD), meteorological drought occurs when the seasonal rainfall received over an area is less than 75% of its long term average value. If the rainfall deficit is between 26-50%, the drought is classified as ‘moderate’, and severe if the deficit exceeds 50%.
Agricultural drought occurs when there is insufficient soil moisture to meet the needs of a particular crop at a particular point in time. Deficit rainfall over cropped areas during their growth cycle can destroy crops or lead to poor crop yields. Agricultural drought is typically witnessed after a meteorological drought, but before a hydrological drought.
Hydrological drought is a deficiency in surface and subsurface water supply. It is measured as streams and also as a lake, reservoir and groundwater levels.
A sequence of impacts may be witnessed during the progression of a drought from meteorological, agriculture to hydrological. When drought begins, the agricultural sector is usually the first to be affected because of its heavy dependence on stored soil water. Soil water can deplete rapidly during extended dry periods.
If precipitation deficiencies persist, then people dependent on other sources of water begin to feel the effects of the shortage. Those who rely on groundwater, for instance, are usually the last to be affected.
When the situation returns to normal, and meteorological drought conditions have abated, the ‘recovery cycle’ follows the same sequence. Soil water reserves are replenished first, followed by stream flows, reservoirs / lakes and groundwater.
Causes of Drought
The principal cause of drought may be attributed to the erratic behaviour of the monsoon. The southwest monsoon, or summer monsoon as it is called, has full control on agriculture, the Indian economy and consequently the livelihoods of a vast majority of the rural population. The southwest monsoon denotes the rainfall received between the moths of June and September and accounts for around 74% of the country’s rainfall.
The coastal areas of peninsular India also receive rain from October to December due to periodic cyclonic disturbances in the Bay of Bengal (the northeast monsoon, or post monsoon system)
The overexploitation of surface and groundwater is another major cause of water stress leading to drought situations in the country.
India has seen a sharp decline in groundwater levels, leading to fall in supply, saline water encroachment and the drying of springs and shallow aquifers. Low supply of fresh water also leads to river water disputes and conflicts. Around half of the total irrigated area in the country is now dependent on groundwater and 60% of irrigated food production depends on irrigation from groundwater wells.
In some regions of Gujarat, Rajasthan, Tamil Nadu, Karnataka, Punjab and Haryana the decline in water levels due to over-exploitation has been to an extent of 1-2 meter per year.
The rapid depletion of forest cover is also seen as one of the reasons for water stress and drought. India has 22% of its total geographical area under forest cover, which is much lower than the prescribed global norm of one third of the total area. Although the scientific evidence is inadequate, forest-water linkages are widely acknowledged, especially the watershed functions of forests, greater availability of water, less soil erosion, more rainfall, flood and landslide control, etc.
Impact of Drought
Drought has a direct and indirect impact on the economic, social and environmental issues of the country. Depending on its reach and scale, it could bring about social unrest.
The immediate visible impact of monsoon failure leading to drought is felt by the agricultural sector.
- The surface water and the groundwater levels drop.
- The food grain production goes down.
Water and fodder shortages during drought situation cause considerable stress in the bovine population also.
Impact of droughts does not only have the ecological aspect but the economic aspect, which saddens the whole of the agricultural world. Due to low rainfall or no rainfall at all, the crop production or the harvest is moved to trash. No crops means no money for the farmers and thus force them to step into the debt trap. Economic impacts of droughts are deadly and thus make droughts to be the primary reason for so many suicides and an end to so many families.
The impact of droughts can be reduced through mitigation and preparedness.Thus planning well in advance in crucial.