ABSTRACT

Drought is a recurring feature of the climate system. It is one of the major weather-related disasters, persisting over months or even years. Droughts affect different parts of the world to varying degrees every year. They have a major impact on rural livelihoods with the effects lingering long after the actual event. The impacts not only depend on the severity, duration, and spatial extent of the precipitation deficit, but they also to a large extent depend on the socioeconomic and environmental vulnerability of the affected regions.

By definition, drought refers to an extended period of deficiency in precipitation (relative to what is considered normal), which is then insufficient to meet economic, social, and environmental demands. Drought is generally classified into four interrelated categories: meteorological drought, 592hydrological drought, agricultural drought, and socioeconomic drought. Meteorological drought is determined by the difference in precipitation from the normal average in a region over a certain period of time, and it is also the basis of the other drought types. Drought planners usually rely on acceptable mathematical indices to decide on when to start implementing water conservation or mitigation measures. The most commonly used indices include the Palmer drought severity index, standardized precipitation index, crop moisture index, and surface water supply index. Geographic Information Systems (GIS) are effective tools to display and model spatial and temporal variations of drought intensity. The spatial variation of drought impact within a region is depicted on a map using a color gradation.