Interbasin transfers of water: Zayandeh-rud river basin

The Zayandeh-Rud River Basin is one of the most strategic basins situated in arid and semiarid central Iran. The basin has been constantly facing water stress problems during the past 60 years. A number of interbasin water transfer (IWT) projects were operated to close off the basin. In addition, several similar projects are currently in construction and operation phases. The main goal of this study is the evaluation of IWT projects to meet the growing water demand in this basin. A system dynamic model is developed to capture the interrelationships between various subsystems of the water resource system in the Zayandeh-Rud River Basin, such as hydrologic, socioeconomic, and agricultural subsystems. The model was calibrated using data from 2000 to 2010 for population growth, Gav-Khouni Marsh input flow, and domestic water demand; simulations were carried out from 2010 to 2040 on a yearly time step. Sensitivity analysis was performed and extreme condition tests were conducted to evaluate the robustness of the model. The results indicate that supplying more water is the engine of watershed development and consequently leads to growth in watershed water demand. These projects not only are not the appropriate solutions to water shortage but also lead to severe water stress in the basin.