Drought area monitoring during the past three decades in Fars province, Iran

Water is the most important limiting factor for agricultural development in Iran. Fars province has had remarkable record in crop production especially wheat yield in the country. On the other hand, comprehensive management and decision making in the field of water resources requires reliable prediction of drought area, duration and severity. The purpose of this study was to monitor the variation of drought coverage area using spatially distributed (gridded) SPI values in various time scales (3, 6, 9, 12 and 24 months) in Fars Province during the past three decades. The results showed the relative frequency of drought coverage-area in the various SPI time scales (6, 9, 12 and 24 months) were 78% to 83%, 3% to 6% and 9% to 18% for small scale, medium scale and large scale droughts, respectively. Also, the non-parametric Mann-Whitney test has revealed that the means of the drought area series in various time scales for the two 15-year sub-periods (1977-1992 and 1993-2008) have no significant changes. Hence, recent droughts may be one of the factors that causes the problems in water resources but the role of other factors such as lack of proper and appropriate management and also increasing demand for water due to population growth should be taken into serious consideration, otherwise Fars province could experience serious socioeconomic crisis.