Preparation of the vulnerability map arising from agriculture drought using GIS and AHP (a case study: Taft township, Yazd province)

Drought is one of the largest natural disasters that hurts millions of people and damages socio -economic development of societies worldwide each year. Studies showed that the best approach to manage the drought would be to implement a low cost timely comprehensive drought management system before occurence and spread of the disaster. This system necessitates aquire proficient information from regional vulnerability in order to react and make decisions to decrease the risk and damages caused by drought. Therefore, the first step of comprehensive drought management is accomplished by preparation of the vulnerability map and or drought hazard zonation.Thus the aim of this study was to prepare the first vulnerability map risen from agriculture drought in Taft town of Yazd province, Iran. Taft is one of the regions that encounters with the most vulnerability caused by continuous long-term droughts. Taft, due to harsh climatic conditions, topography and intense dependence to precipitations as sources of water reservoirs, is a pattern in the region that endures a complicated condition induced by many factors that risen by drought affecting on agriculture. In this study in the first step, the factor affecting the vulnerability to drought in the region was converted into layers of information, and then the corresponding classification was performed. In the next step, the aforementioned layers were first weighted by Analytic Hierarchy Process (AHP) according to their importance in drought vulnerability and then they were combined by Geographic Information Systems (GIS) to prepare final map of drought vulnerability in Taft town of Yazd province. In this research parallel to the mentioned method, field study was implemented to control, monitor and accurately assess the output maps. Also the vulnerability of agricultural drought was determined in Taft by the use of documentation of drought losses in recent years, filled questionnaires by farmers and agriculture experts, and rural field results. The results of this study showed that agricultural drought vulnerability in Taft was mostly occurred in the rural district banadkok, sakhvid, shirkooh, zardin, southern part of pishkooh, north and north east of dehshir and nir while the other purts of dehshir, kahduiyea, bakh and Garizat and central pishkooh part (Eslamieh-Taft) was received the lower degree of agricultural drought vulnerability. The findings of the present research showed that the rate of damage illustrated in the presented final map coordinates with the field studies in most cases. The overall results of this research showed that the vulnerability in highlands (mountainous) was geomorphologically higher than those in plain areas due to the low depth of sediments, coarse aggregate-textured soils and ephemeral water resources such as Qantas that their vulnerability is primarally more severe occurring continually in short internals. As it is mentioned, the drought disaster and risk management practices in various regions is different that should be considered by provincial and national authorities.