drought is a deficiency of precipitation over an extended period of time, usually a season or more. This deficiency results in a water shortage for some activity, group, or environmental sector.

Meteorological, Hydrological, Agricultural and Socioeconomic

Meteorological drought is defined usually on the basis of the degree of dryness (in comparison to some "normal" or average amount) and the duration of the

dry period.

Agricultural drought links various characteristics of meteorological (or hydrological) drought to agricultural impacts, focusing on precipitation shortages,

differences between actual and potential evapotranspiration, soil water deficits, reduced ground water or reservoir levels, and so forth.

Hydrological drought is associated with the effects of periods of precipitation (including snowfall) shortfalls on surface or subsurface water supply (i.e., stream

flow, reservoir and lake levels, ground water).

Socioeconomic definitions of drought associate the supply and demand of some economic good with elements of meteorological, hydrological, and

agricultural drought.

The sequence of impacts associated with meteorological, agricultural, and

hydrological drought further emphasizes their differences. 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 be rapidly depleted during

extended dry periods. If precipitation deficiencies continue, then people

dependent on other sources of water will begin to feel the effects of the

shortage. Those who rely on surface water (i.e., reservoirs and lakes) and

subsurface water (i.e., ground water), for example, are usually the last to be

affected.

(1). Percent of Normal

(2). Deciles

Table 1: Decile Classifications for Dry and Wet Periods

Deciles 1-2 lowest 20% much below normal

Deciles 3-4 next lowest 20 % below normal

Deciles 5-6 middle 20% near normal

Deciles 7-8 next highest 20% above normal

Deciles 9-10 highest 20% much above normal

(3)Palmer Drought Severity Index ("The Palmer")

(2)El-Nino

(1)Biology: Damage to natural habitats-loss of biodiversity

Reduced forest, crop, and range land productivity

(3) Water resources: Increased evaportranspiration. Lower ground water levels and reduced water quality

(4)Soils: caused soil desication, increasing soil ‘blowability’. More dust and sandstorms-Increased soil erosion; Decreased soil productivity-Desertification and soil degradation

(1)Food and energy shortages

Drastic price increases

Expensive imports/substitutes

(2)Reduction of livestock quality

Sale of livestock at reduced market price

(3)Water scarcity

Increased transport costs

(4) Loss of jobs, income, and property

Deepening poverty

Increased unemployment

(5)Forced financial loans

Increased debt

Increased credit risk for financial institutions

(1)Food insecurity: Malnutrition and famine.

(2)Migration, resettlement, unemployment

(3)conflicts

Unlike other natural disasters, drought tends to drive people apart rather than bring them closer together. The shortage of food and water lead conflicts as people, community, and governments battle each other for the means to survive. After an earthquakeor flood, people are commonly at their best as they aid their neighbors and strangers in need; during a drought, because the disasters are slow and lasting long time, people are often at their worst as they fight for survival.

Almost all the hazards bring people closer, people like to help each other. However, droughts often lead to the conflicts between communities. Fighting for limited water resources and for survival.

(4)Public health risks due to increasing pollutants.

(5) Inequitable drought relief -Social unrest, distrust

(6)Urbanisation-Social pressure, reduced safety

1. African Countries
2. US
3. Australia