Simulation farmer's response to reducing available water policy

In this study، to determine the economic value of irrigation water and simulate the response of farmers to reducing available water policy of positive mathematical programming models (PMP) was used. By the proposed model، the economic value (shadow price) of irrigation water estimated in each of the areas of Western Rodbar Alamuot، Rajai Dasht and Eastern Rodbar Almuot. Then، the reactions of farmers in each region toward reduce water availability policy under scenarios of 10، 20، 30، and 40 Percent was investigated. To solve the model of data''s 2011-2012 and software GAMS Version 23/5 was used. The results showed that the economic value of irrigation water estimated for each of the areas of Western Rodbar Alamuot، Rajai Dasht and Eastern Rodbar Almuot respectively 882، 716 and 845 riyals and there is huge difference between the economic value of irrigation water and water charge rates in the region Rodbar Almuot and by reducing the availability of irrigation water، the economic value of water increases and cropping pattern moves in each of the areas favor products that creates fixed income toward less water.