considering effective factors of water resources exploitation under various geographical conditions in fars province

water shortages is one of the main factors inhibiting economic and social development and agriculture in most developing countries, especially in countries located in arid and semi-arid belt of the world. the study tried to investigate the affecting factors on water resources exploitation with considering water utilization pattern and an emphasis on sustainable water use in fars province. due to scattering scattering and wide climate of fars province, the investigation was done in marvdasht, darab, fasa, sarvestan and eghlid districts. in the present study, using logit regression model, factors affecting the sustainability examined. dependent variable of regression is calculated with the use of combined index by formula and fuzzy approaches. independent variables include social, economical, physical and technical and management factors. results showed that variables of number of household members, land utilization system, the level of farmers’ household income, water debi and transport irrigation facilities cost were significantly negative, positive, positive, negative and negative, respectively. the management index in two low and high sustainability exploiters was significant that indicates the important role of participating in extension classes in raising awareness and knowledge of farmers. variable of distance between the water source and farm in regression models of exploiters with high and low sustainability showed different results. variables related to summery crops and soil type in the model, were not significant. variable coefficient of irrigation system type also showed that farmers with plot irrigation systems have less water wastage compared to farmers with ribbed irrigation systems.