An Analysis of the Effects of the Policies of Water Demand Management in Marvdasht: An Application of the Positive Mathematical Programming (PMP)

Water scarcity is a major deterrent to agricultural development. Adopting appropriate policies to sustain this resource has become an important strategic issue in the country. One of the policies implemented in the agricultural sector for sustainable water resources is the policy of changing the pattern of cropping and reducing the level of water crop cultivation based on the pattern and increasing irrigation efficiency. Accordingly, the aim of this study was to determine the effectiveness of gradual reduction of rice cultivation area along with increasing irrigation efficiency on economic and environmental indices in Marvdasht County. For this purpose, a Positive Mathematical Planning Model (PMP) and calibrated based on crop area data for the year 2017-2018 used. The method used for data collection was based on survey, documentary studies and the use of expert opinions and experiences. The results of this study showed that the application of water demand management policies in the context of different scenarios of reducing rice crop area, in spite of the decrease in the economic benefits of the agricultural sector, improves the economic efficiency index of water resources and decreases the water demand. Therefore, in order to stabilize surface and ground water resources in Marvdasht city, it recommend to change the optimum cropping pattern, in order to reduce the cultivation level of water crops and provide farmers with facilities to equip their farms with new irrigation systems.