Mohammad Hassan Tarazkar - Ph. D. Student of Agricultural Economics, Collage of Agriculture, Shiraz University, Shiraz, Iran.
Gholam Reza Soltani - Professor of Agricultural Economics, Collage of Agriculture, Shiraz University, Shiraz, Iran.
Mansour Zibaei - Professor of Agricultural Economics, Collage of Agriculture, Shiraz University, Shiraz, Iran.

Now days, optimal reservoir operation, especially during draught years are very important topic in water resource management. Therefore, in this study a multi-objective non-linear monthly optimization model was used to derivation of optimal operating policy for doroodzan, Molasadra and Sivand water reservoir in Fars province of Iran during ten years (2001 to 2011). A weighted method was used in optimization model and the weights were calculated by using Fuzzy AnalyticalHierarchy Process (FAHP). Moreover, in order to observe uncertainty in optimization model three condition of water inflow were considered (85%, 75% & 65% of real water inflow). The optimization model was run in GAMS and solved using a nonlinear solver, CONOPT .The resultsindicate that optimization model can supply 81% to 96% and 63% to 92% and 49% to 90% of water demand of residential, environmental and agricultural sectors in different conditions of water inflow, respectively.

Reservoir Management, Multi-Objective Non-Linear Optimization, FAHP