Thursday, October 28, 2010
Last blogged @ 11:42 AM

Droughts

Drought is a period or condition of unusually dry weather within a geographic area where rainfall is normally present. During a drought there is a lack of precipitation. Droughts occur in all climatic zones. However, its characteristics vary significantly from one region to another.

4 main kinds of droughts:

 Agricultural Drought

• Effects mainly food production and farming.
• Precipitation shortages bring soil water deficits, reduced ground water or reservoir levels, and etc.
• Deficient topsoil moisture at planting may stop germination thus leading to low plant populations.

 Hydrological Drought

• Associated with effects of periods of precipitation shortages on water supply.
• Water in hydrologic storage systems such as reservoirs and rivers are often used for multiple purposes i.e : Flood Control, Irrigation, Recreation, Navigation, Hydropower, Wildlife Habitat.
• Competition for water in these storage systems escalates during drought →conflicts between water users increase significantly.

 Meteorological Drought

• Is the amount of dryness and the duration of the dry period.
• Atmospheric conditions that result in deficiencies of precipitation change from area to area.

Socioeconomic Drought

• Occurs when the demand for an economic good exceeds supply due to weather-related shortfall in water supply.
• Supply of many economic goods, such as water, forage, food grains, fish and hydroelectric power, depends on weather.
• Water supply is sufficient in some years but not satisfactory to meet human and environmental needs in other years due to variability of climate.
• Demand for economic goods is increasing as a result of increasing population.
• Supply may also increase due to improved production efficiency and technology.

Effects on Droughts

Economic 
- Loss of national economic growth,thus slowing down of economic development
- Damage to crop quality(Insect infestation and plant disease) → less food production
- Increase in food prices and importation of food → higher costs
- Unemployment from production declines
- Loss to recreational and tourism industry
- Loss of hydroelectric power,navigability of rivers and canals
- Unavailability of water and feed for livestock → high livestock mortality rates → less livestock production → income loss for farmers

Environmental
- Soil Erosion
- Increased desertification
- Damage to plant and animal species
- Reduction and degradation of fish and wildlife habitat
- Lack of feed and drinking water
- Diseases
- Increased predation
- Loss of wildlife in some areas and too many in others
- Increased stress to endangered species
- Increased number and severity of fires


Social
- Loss of human life from food shortages, heat, suicides, violence
- Mental and physical stress
- Conflicts(water user and political)
- Inequity in the distribution of drought relief
- Loss of cultural sites
- Reduced quality of life results in changing of lifestyle
- Increased poverty
- Population migrations
- Social unrest i.e. public dissatisfaction with government regarding drought response