3. Contractioncracksindryearth(Sonorandesert,Mexico).
Drought is an extended period when a region receives a deficiency in its
water supply, whether atmospheric, surface or ground water. A drought can
last for months or years, or may be declared after as few as 15 days.[1]
Generally, this occurs when a region receives consistently below average
precipitation. It can have a substantial impact on the ecosystem and
agriculture of the affected region. Although droughts can persist for several
years, even a short, intense drought can cause significant damage[2] and
harm to the local economy.[3] Prolonged droughts have caused mass
migrations and humanitarian crises.
4. Many plant species, such as those in the family Cactaceae or cacti, have
adaptations such as reduced leaf area and waxy cuticles to enhance their ability
to tolerate drought. Some others survive dry periods as buried seeds. Semi-
permanent drought produces arid biomes such as deserts and grasslands.[4] Most
arid ecosystems have inherently low productivity.
5. A livestock carcass in Marsabit, in northern Kenya, which has suffered prolonged
drought.
Periods of droughts can have significant environmental, agricultural, health,
economic and social consequences. The effect varies according to vulnerability.
For example, subsistence farmers are more likely to migrate during drought
because they do not have alternative food sources. Areas with populations that
depend on as a major food source are more vulnerable to famine.
6. Drought can also reduce water quality, because lower water flows reduce dilution
of pollutants and increase contamination of remaining water sources. Common
consequences of drought include:
• Diminished crop growth or yield productions and carrying capacity for livestock
Dust bowls, themselves a sign of erosion, which further erode the landscape
Dust storms, when drought hits an area suffering from desertification and erosion
Famine due to lack of water for irrigation
• Habitat damage, affecting both terrestrial and aquatic wildlife
Hunger, drought provides too little water to support food crops.
Malnutrition, dehydration and related diseases
Mass migration, resulting in internal displacement and international refugees
• Reduced electricity production due to reduced water flow through hydroelectric dams
• Shortages of water for industrial users
• Snake migration, which results in snakebites
Social unrest
7.
8. Most of the drought-prone areas are found in arid, semi-arid, and sub-humid
regions of the country, which experience less than average annual rainfall.
Broadly, the drought-affected areas in India can be divided into two tracts.
The first tract comprising the desert and the semi-arid regions covers an
area of 0.6 million sq. km. It is rectangle shaped area whose one side
extends from Ahmedabad to Kanpur and the other from Kanpur to Jullundur.
In this region, rainfall is less than 750mm and at some places it is even less
than 400 mm. The second tract comprises the regions east of the Western
Ghats up to a distance of about 300 km from coast. Known as the rain
shadow area of the Western Ghats, rainfall in this region is less than 750mm
and is highly erratic. This region is thickly populated and periodic droughts
cause considerable suffering and distress.
Besides these two tracts of scarcity, there are many pockets of drought in
India. Some of these are :
Tirunelveli district, south of Vaigai River in Tamil Nadu
Coimbatore area in Kerala
9. Drought is a normal, recurring feature of the climate in most parts of the world. It is
among the earliest documented climatic events, present in the Epic of Gilgamesh and
tied to the biblical story of Joseph's arrival in and the later Exodus from Ancient
Egypt.[11] Hunter-gatherer migrations in 9,500 BC Chile have been linked to the
phenomenon,[12] as has the exodus of early humans out of Africa and into the rest of
the world around 135,000 years ago.
A South Dakota farm during the Dust Bowl, 1936
Modern people can effectively mitigate much of the impact of drought through
irrigation and crop rotation. Failure to develop adequate drought mitigation strategies
carries a grave human cost in the modern era, exacerbated by ever-increasing
population densities.
10. Large areas in the four states that utilize Narmada water falls in arid and
semi-arid regions. As shown in Table 8, nearly 57% of Rajasthan and 32%
of Gujarat falls in arid zone. Also, nearly 61% of Maharashtra and 46% of
the area of Gujarat is semi-arid. This shows how important it is for these
states to properly use available water.
Drought years inthepast centuries.
Period Drought years Number of years
1801 - 1850 1801, 04, 06, 12, 19, 25, 32, 33, 37 9
1851 - 1900 1853, 60, 62, 66, 68, 73, 77**, 91, 99** 9
1901 - 1950 1901*, 04, 05*, 07, 11, 13, 15, 18**, 20, 25, 39, 41* 12
1951 - 2003 1951, 65*, 66, 68, 72**, 74, 79*, 82, 85, 87**, 2002* 11
*Indicates severe drought (>39.5% area affected), ** Phenomenal drought year (>
47.7% area).
11. Together, these scattered pockets occupy an area of 0.1 million sq. km.
Drought is a recurrent phenomenon in Andhra Pradesh where no district
is entirely free of droughts.
Rajasthan is one of the most drought prone areas of India. Eleven
districts of the state are in arid regions including Jaisalmer as the driest
district. No perennial river flows in Jaisalmer. Groundwater level in the
district is 125–250 ft deep and at some places 400 ft deep. The rainfall in
the district is extremely low at 164 mm. Out of 365 days of a year, on an
average 355 days are dry.
The total area which receives inadequate rainfall is just over one million
sq. km. The regions with rainfall less than 400mm occupy 12% of the total
geographical area, and the area below 750mm rainfall is 35% or a little
over a third of the country. Thus out of the total gross cultivated area of
the country, 56 million ha is subject to inadequate and highly variable
rainfall.
12. Drought Prone Area of India
Drought Prone Area 51.1 mha
Affected Districts 74
Affected States 13
Statewise area of arid and semi -arid zones
State
Area (km2
)
Arid Semi-arid
Gujarat 62,180 (31.72) 90,520 (46.18)
Madhya Pradesh - 59,470 (13.41)
Maharashtra 1,290 (0.42) 189,580 (61.61)
Rajasthan 196,150 (57.31) 121,020 (35.396)
Note: figures inside brackets represent the % of the area of
the state under that category.
13. Meteorological sub division Frequency of deficient rainfall (75% of normal or
less)
Assam Very rare, once in 15 years
West Bengal, Madhya Pradesh, Konkan, Bihar and Orissa Once in 5 years
South Interior Karnataka, Eastern Uttar Pradesh and Vidarbha Once in 4 years
East Rajasthan, Gujarat and Western Uttar Pradesh Once in 3 years
West Rajasthan, Tamil Nadu, Jammu & Kashmir and Telangana Once in 2.5 years
Probability of occurrence of drought in
different meteorological sub division.
