Assessing soil and water resources management strategies using a planning support system and multi-criteria evaluation technique

The first step in policy making is describing the objectives and choosing the policy instruments and management strategies and then, analyzing and assessing the impacts of them. In this study, farmers’ responses to selected policy instruments and management strategies were assessed using a semi-distributed planning model in Qazvin irrigation and drainage network. The proposed model, simulates the choice of different combinations of crop, irrigation treatment and planting date for each land unit. Multi-criteria evaluation techniques were used for the assessment of each management scenarios from economic, social and environmental point of view. Analyzing the impacts of management scenarios using a planning support system showed that the S2 (reducing bank interest rate for promoting pressurized irrigation systems) and the S3 (setting different water prices for surface and pressurized irrigation systems) scenarios can be considered as the best scenarios, after the S5 scenario (combination of all policy instruments). Uncertainty analysis (±30% error in determining the assigned weights) showed that the final ranking on the management scenarios has insignificant sensitivity to the assigned weights to the selected criteria and from an economic point of view, these two scenarios will be chosen and the second and third best management scenarios with the probabilities of 100% and 61%, respectively. The results revealed that different policy instruments and management strategies can have mutual effects and the combination of these instruments may not be the best option from some viewpoints.