Above all, we have to distinguish between drought and aridity. Indeed, the last one, is a constant climatic phenomenon to which the human was adapted. Nevertheless, the drought is a brutal and irregular reduction of water (Dauphiné, 2003).
Indeed, arid regions populations had developed, by the time, indigenous knowledge allowing them boosting spaces in desert environment (oasis).
The drought, starts like a climatic event in its initial phase, extends gradually to all the fields where water forwards. Thus, it is fundamental to distinguish various types of drought:
- Meteorological (lack of precipitations),
- Agricultural ( when the conditions are not able to support agriculture and breeding),
- Hydrological (lack of water in brooks and aquifers),
- Socio-Economic (when the insufficiency of water starts to affect people and their lives),
- The forest drought (refers to the situations where the moisture of the soil and the water reserves become insufficient to satisfy the needs for the trees, the herbaceous plants and forest fauna).
