poster - International Conference of Agricultural Engineering

2.1 Case study
The Zayandeh-Rud basin is located in central part of Iran with the area of 41,500 km2 (Fig. 1).
The dominant climate in this basin is arid or semiarid climate. The averages of precipitation are
about 1500 mm per year, most precipitation occurs as snowfall during December to April. Large
economical and social damages accrue annually because of the widespread droughts in this
region. Thus, the lack of current water causes limit of available amount of water for using
economical options. In this paper, drought trends in the basin have been investigated from 1668
to 2007 years.
FIGURE 1 Zayandeh-Rud basin, Iran
2.2 The AHP method
The analytic hierarchy process (AHP) first developed by Saaty (1980) and used in different a
multi-criteria decision problem. The process makes it possible to incorporate judgments on
qualitative and quantitative aspects criteria. The AHP method is based on three principles: first,
structure and dominance of the hierarchy; second, comparative judgment of the alternatives and
the criteria, sub-criteria, sub sub-criteria and so forth; third, synthesis of the priorities for
estimating the consistency ratio. In the literature, AHP, has been widely used in solving many
complicated decision-making (Banai, 1993).
2.3 Conceptual framework
The six parcels in the Zayandeh-Rud basin are represented in a raster GIS. The parcels are
determined to evaluate drought assessment with regard to four criteria (meteorological,
agricultural, hydrological and socioeconomic drought) and five sub-criteria. The decision
problem includes ranking the alternative parcels based on drought vulnerability. The AHP
method was used to weight the factors. Developing a hierarchal structure for the decision