Droughts

What Is A Drought? An extended period of months or years when a region notes a deficiency in its water supply. Occurs when a region receives consistently below average precipitation. Substantial impact on the ecosystem and agriculture of the affected region.

Causes Rainfall is related to the amount of water vapor in the atmosphere. This is combined with the upward forcing of the air mass containing that water vapor. If either of these are reduced, the result is a drought! Can be triggered by an above average prevalence of high pressure systems.

Causes Cont. Human activity can directly trigger events helping in the formation of a drought. Examples include over farming, excessive irrigation, deforestation, and erosion. Impact on the ability of the land to capture and hold water. Along with drought in some areas, flooding and erosion will increase in others

A few Common Consequences Diminished crop growth or yield productions. Dust Bowls- themselves a sign of erosion. Dust Storms- when drought hits an area suffering from desertification. Famine- due to lack of water for irrigation. Habitat Damage- affecting both terrestrial and aquatic wildlife. Wildfires- such as Australian bushfires, are more common during times of drought. Mass Migration- resulting in internal displacement and international refugees. Reduced Electricity Production- due to insufficient available coolant for power stations. Shortages of water for industrial users. Social unrest. War- over natural resources, including water and food.

Stages Of Drought As a drought persists, the conditions surrounding it gradually worsen. Its impact on the local population gradually increases.

Stage 1 Meteorological- drought is brought about when there is a prolonged period with less than average precipitation. Meteorological drought usually precedes the other kinds of drought.

Stage 2 Agricultural- are droughts that affect crop production or the ecology of the range. This condition can also arise from any change in precipitation levels when soil conditions and erosion triggered by poorly planned agricultural endeavors cause a shortfall in water available to the crops.

Stage 3 Hydrological- drought is brought about when the water reserves available in sources such as aquifers, lakes and reservoirs falls below the statistical average. This can be triggered by more than just a loss of rainfall.

Stage 4 Socioeconomic- how the water shortage affects the people living in the affected area On average droughts cost the US $6-8 billion annually compared to $2.4 for floods and $4.8 for hurricanes Seldom produce structural damage so effects may be less obvious

Drought Mitigation Strategies Cloud seeding. Desalination of sea water for irrigation or consumption. Drought monitoring - Continuous observation of rainfall levels Land use - Carefully planned crop rotation can help to minimize erosion. Rainwater harvesting - Recycled water - Former wastewater (sewage) that has been treated and purified for reuse. Transvasement- Building canals or redirecting rivers as massive attempts at irrigation in drought-prone areas. Water restrictions

Droughts vs. Heat Waves Some people think that they are the same thing. Heat Wave- a prolonged period of excessively hot weather. No universal definition of a heat wave The term is relative to the usual weather in the area. Just because there is a heat wave doesn’t mean there is a drought.

Range of Effects for Droughts Droughts affect people on a national, local, and a global range. When a drought is in effect everyone can be affected. Droughts can even affect the economy and jobs of other countries.