Prioritizing the counties of Sistan and Baluchestan province in order to optimize the management of drought budget

Drought is one of the most significant natural hazards which affects various aspects of human life with its gradual, slow and creeping occurrence. As a disastrous climate phenomenon, it directly impacts on human communities through making changes in access to water resources, and imposes enormous economic, social and environmental costs on various communities. One of the strategies governments always use to compensate the damages that droughts impose on various economic, social and environmental sectors is to include special financial loans in the form of grants, special development credits, special structural projects, and so on. Therefore, in this regard, a lot of financial aids have been allocated by the government for it. But, sometimes, it is observed that the allocation and distribution of drought credits among different cities of the province have been more influenced by political, ethnic, and religious interests rather than by the severity of the drought and its detrimental effects on various economic, agricultural, and social sectors. Therefore, in this study, it has been tried to present a method based on an optimization model in order to take a step in optimizing the management of drought budget based on realities in Sistan and Baluchestan province in south-east of Iran. In this study, the indicators proposed by the Cabinet of Ministers of the Islamic Republic of Iran for reducing the effects of drought were applied to manage the optimal distribution of drought budgets among the cities of Sistan and Baluchestan province in southeast of  Iran. These indicators were population, having urban and rural drinking water, vulnerability of water resources, surface area under cultivation, number of users of agricultural sector, annual consumption of agricultural water, and rainfall. Using the figures given in the 2011 statistical yearbook, numerical values ​​for each of these indices were obtained. But given that these indices are not of equal importance in each city and some may be more important in one city and less important in another, the Analytical Hierarchy Process (AHP) technique using paired comparison method was applied to determine the relative importance of these indices in Sistan and Baluchestan province. Using this technique, a relative weight was determined for each of these indicators and for each city. In addition to determining the weight of these indices, it was needed to convert droughts in the province to numerical values. In this study, to analyze droughts in Sistan and Baluchestan province, Standardized Precipitation Index (SPI), which is one of the proposed indicators of World Meteorological Organization (WMO) has been used for a period of 30 years (1984-2014) and for 6 synoptic stations. The results of drought analysis in Sistan and Baluchestan province in an annual scale showed that the frequency distribution of different drought levels in Sistan and Baluchestan province has not been uniform, with the most droughts occurring in this 30 year period in northern part of the province (Zabol and Zahedan) including 14 and 13 repeated cases; respectively, with the lowest in central part of Baluchistan (Khash and Saravan) including 11 repeated cases. But, what should be noted after the frequency of droughts is the persistence and durability of droughts. As a result, weak but long-lasting droughts can be much more damaging than severe but short-lived droughts. Sistan and Baluchestan province has been under drought with varying degrees of severity from the water year of 1998-1999 to the water year of 2005-2006. But in the meantime, the north of Sistan and Baluchestan province (Zabol station) has a condition which is very different from other parts of the province. The north of Sistan and Baluchistan province has been experiencing severe droughts for 14 years from the year 1999-2000 to 2012-2013 with the exception of the year 2004-2005. It has been the long-term drought persistence in the province that has caused many environmental, economic and social problems, such as the drying up of Lake Hamoun and the water reduction in the Hirmand River in the north of the province, and severe reduction of groundwater resources in central Baluchistan. Therefore, given that Sistan and Baluchestan province has experienced 7 years of continuous drought between the two water years of 1998-1999 to 2009-2010, these seven years were chosen as examples, and the ant colony algorithm was implemented on them. Based on the selected criteria and the proposed method, it seems that the combination of Analytic hierarchy process (AHP) technique and Ant colony algorithm can formulate an intelligent system to determine the priority of the cities in Sistan and Baluchestan province during droughts for allocating the optimal budget and reducing the harmful effects of droughts. Based on the prioritization maps of optimal drought budget allocation among the cities in Sistan and Baluchestan province, an almost good agreement can be observed between the results and the realities existing in the province.