Over pumping of ground water, especially in arid and semiarid areas, has had negative effects on environment. Recognition of productivity of water and soil resources is the first step toward planning and managing for increasing optimum operation of these resources. In this study, using a sample of 110 farmers, the condition of efficiency and farmers' desperation and migration due to over using of groundwater in Rafsanjan plain was investigated in 2012. Analysis and regression methods were used in this regard. Marginal product of water was estimated 0.04 kg per cubic meter that 33 present has decreased with compare to past tense (15 year ago). Also negative counteraction between decreasing efficiency of water resources and not hope to the condition of future of water resources was specified. This case was effective on farmers' migration. For elimination or reduction of ground water degradation and its effects, this paper recommended that in economic evaluation is attended to the social costs and benefits. Finally, for preventing the negative effect of farmers' desperation for future, it is better to give information to pistachio producers with introducing efficient methods for solving the problem.

JEL Classification: Q01, Q25

Keywords:
Ground Water, Over Exploitation, Production Function, Farmers' Migration, Anar-Rafsanjan Plain