The approach of using water resources as a fundamental element of human life was investigated by sciences since past decades. The reorganization of parameters in the form of accordance with environment, policies, technical and economic estimation, and programming on water resources is called water resources management. The raising requirements of water by growth of population, improving of agricultural and industrial activities, limitation of renewable water resources, pollutions and the heavy costs of improving water resources are the results that the conjunctive use of groundwater and surface water as a main component for providing water needs A conjunctive use management of water resources problem has two parts, simulation and optimization, which must be solved. A point that could be considered in management problems is various uncertainties from different conditions of problem, error on metering or uncertainty on simulation. Decision makers use various method such as stochastic and statistic approach. The using of fuzzy logic for considering of vague and uncertainty conditions is improved lately. In this thesis, studying on conjunctive management of groundwater and surface water resources of Najafabad aquifer has been considered. Simulation and interaction between surface water and groundwater with appointing and precising of boundaries was simulated monthly by Groundwater Vistas 4.0 software for a six year period, 2000-2001 till 2005-2006. After simulation, the optimization on the case study was done.In order to optimization on the aquifer in order to minimize discrepancy between water requirements was performed by fuzzy dynamic programming. The notable point in optimization is consideration of various climate conditions and its influences on providing of water resources and water requirements. Thus with use of fuzzy infers systems based upon amount of release of Zayanderud dam, the amount of allocable water to irrigation networks, total implantable land in each part and the percent of various crops are investigated. This issue results that water requirement and allocable water resources are investigated with attention to water conditions. At the end tables of results for various usages of surface water and groundwater were prepared.
