Water is considered as the most important component, but a limiting input, for agricultural production in Iran. In the context of water resources management, for the limited availability of water and high cost of supplying it to the users, improvement of water use productivity has been regarded as one of the most appropriate approaches to manage water demand. Various tools have been applied for water management policy in the context of preventing high level of water deficit. In the present study, different policy scenarios related to water supply management are assessed. These include estimation of the impacts of each policy scenario on physical and economic productivity indices and employment, using positive mathematical programming methods and maximum entropy. This methodology was applied to water use in the Qazvin Plain, Iran. Results suggested that application of these policy scenarios not only decreased water consumption but also generated desirable social and economic effects. Results of the ranking showed that the policy of imposing tax on input generated the best results for the study area. However, it is admitted that selection of the best policy scenario is dependent on the weight that policy makers would select for various indicators.

Keywords