inthis study, positive mathematical programming method and the maximum entropy are used in order to estimate water demand of Qarveh-Dehgolan plain and the amount of water supply have been calculated with regard to the sum of different sources of water, such as wells, rivers and canals. Therefore from the confluence of the function of water supply and demand, equilibrium price of input water has been estimated. Results demonstrate that there is a negative relation between demand value and water price and tension of water demand is calculated, that is about -0.16. Furthennore, equilibrium price of input water per every cubic meter is 970 rails.
