Drought management & Flash droughts

Drought is a temporary aberration, unlike aridity or even seasonal aridity (in terms of a well-defined dry season), which is a permanent feature of climate. Drought in contrast is a recurrent, yet sporadic feature of climate, known to occur under all climatic regimes and is usually characterized by variability in terms of its spatial expanse, intensity and duration. 

Conditions of drought appear primarily, though not solely; on account of substantial rainfall deviation from the normal and / or the skewed nature of the spatial / temporal distribution to a degree that inflicts an adverse impact on crops over an agricultural season or successive seasons.

Types of Droughts

  • Meteorological Drought is simple absence/deficit of rainfall from the normal. It is the least severe form of drought and is often identified by sunny days and hot weather.
  • Hydrological Drought leads to reduction of natural stream flows or ground water levels, plus stored water supplies. Main impact is on water resource systems.
  • Agricultural drought occurs when moisture level is soil is insufficient to maintain average crop yields. Initial consequences are in the reduced seasonal output of crops and other related production. An extreme agriculture drought can lead to a famine, which is a prolonged shortage of food in a restricted region causing widespread disease and death from starvation.
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Impact of Drought

Ecological and Environmental Impact of droughtsEconomic Impact of droughtSocial impacts
Adverse effect on recharge of ground water, soil moisture and surface runoff Since Indian agriculture is largely dependent on monsoon and about two-thirds of arable land lacks irrigation facilities where two-thirds of the arable land lacks irrigation facilities and is termed as rainfed. This leads to production losses in agriculture and allied sectors especially animal husbandry, dairy, poultry, horticulture and fisheries. There is decline in cultivated area.Disruption in rural society on account of stress migration. Rise in school dropout rates.Greater immiseration and indebtedness. Alienation of land and livestock assetsMalnutrition and starvationLoss of social status among the most vulnerable sections. Situation of scarcity in some cases may exacerbate social tensions and lead to erosion of social capital.Ill health and spread of diseases like diarrhea, dysentery, cholera and ophthalmia caused by malnutrition, hunger and starvationLow morale of peopleGrowth of fatalism and belief in supernatural powers and superstitions.
Rivers, lakes, ponds, reservoirs tend to dry up; wells and tube wells are rendered unserviceable due to lowering of the ground water.
Loss of forest cover, migration of wildlife and sharpening of man-animal conflicts and general stress on biodiversityAll industries dependent upon the primary sector for raw materials suffer on account of reduced supplies and hardening prices.Decline of purchasing powerFall in employment
Reduced stream, flow and loss of wetlands may affect levels of salinity
Reduced groundwater recharge may damage aquifers and adversely affect the quality of water (e.g., Salt concentration, acidity, dissolved oxygen, turbidity) which may lead to a permanent loss of biological productivity of soils.Distress sale of cattle and loss of cattle life.Distress sale and mortgage of land, jewellery and personal property.Generation of hydroelectricity is adversely impacted by drought. 

Causes of Recurrent Droughts in India: Recurrence of drought in India is owed largely to the unique physical and climatic susceptibilities of the country. They include:

  • Low average annual rainfall of 75 cm over 33% of the cropped area. 
  • Limited irrigation coverage on account of complete dependence of agriculture in such areas on rainfall. 
  • Considerable annual/seasonal/regional variations despite high average annual rainfall
  • 73% of annual rainfall is concentrated in window of less than 100 days during South-West Monsoon
  • Uneven distribution of rainfall over different parts of the country. Also much of the excess water, which otherwise could have contributed towards enhancing natural resilience towards drought, gets lost as run-offs. 
  • Over-exploitation of ground water and sub-optimum conservation of storage capacity of surface water leading to inadequate water availability for irrigation. Steady decline in per capita availability of water for humans and animals even in non-drought years
  • Out migration of cattle and other animals from drought hit areas heightens the pressure on resources on surrounding regions.
Rainwater harvesting and Efficient usei. Rainwater harvesting structuresii. Farm pondsiii. Percolation tanksiv. Micro irrigation system etc.Suitable crops/varieties cropping systemi. Seed bankii. Seed treatmentiii. Intercropping systems etc.iv. Agro forestry
Farm Mechanizationi. Suitable implementsii. Labour sharing mechanisationiii. Custom hiring centresWater Saving Technologies:a. Drip and Sprinkler Irrigation Systemsb. Practices such as use of organic manure with the gradual reduction of chemical fertilizers, vermin-culture and agronomic practices, such as mulching, crop rotation and the use of biopest control measures.
1. Establishment of functional Drought Management Centre at the State Headquarters.
2. Preparation of agriculture contingency plans for districts and sub district levels, especially in vulnerable district.
3. Monitoring of seasonal forecasts of IMD and other national/international agencies

Drought prevention in India

Gathering Information for Decision-makingMeteorological, Hydrological, Agricultural Information from measurements/ observations, Ground-based and Remote Sensing
Policies and Institutional Framework for Application of Information, Assessment and CommunicationGOI & SG Procedures, DAC-GOI, Nodal Centre, IMD, ICAR, CWC, NRSC DST.Drought Indicators, CriteriaNCFC NCMRWF, NADAMS Newspapers, Radio, TV,Internet, Bulletins
A basket of Risk Management Measures for Decision-makersPreparedness, Monitoring, Mechanisms, Early WarningSystems, Contingency Plans.Mitigation Strategies, Agricultural, Hydrological,Socioeconomic
Effective and Consistent Action by Decision-makersDeclarationImmediate Measures Loss Estimation Mobilizing Funding Administering Relief Long-term Measures, EWS, Drought resistant Technologies, Improved Water Management, Afforestation Livelihood Sustenance Programs, Crop & Livestock Insurance

Flash Drought

Flash droughts are droughts that intensify more rapidly than normal, posing a risk to agriculture, ecosystems and water availability. Conventional droughts take months and sometimes even years to develop to full intensity. 

Flash droughts on the other hand develop at an unusually fast rate due to extreme weather conditions and persist from a few weeks to some months. Such droughts can be localised to a specific region or can become widespread and affect a large part of the country.

A new study predicts a 7-8-fold increase in the frequency of flash droughts in India due to concurrent occurrence of extreme dry and hot periods during the monsoon season and greenhouse emissions.

An increased frequency of flash drought poses a major risk to crop production due to soil moisture depletion and intraseasonal monsoon variation.

Flash droughts can be identified either by monitoring changes in precipitation, evapotranspiration, or soil moisture. A defining feature of a flash drought is the rapid depletion of soil moisture in the topsoil layer which then moves deeper affecting the ‘root-zone’ of crops and vegetation.

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