Water resources sustainability under climate variability and population growth in Iran: A system dynamics approach

The change in availability of water resources has a dynamic behavior and is influenced by many factors such as population growth and climate variability over time.  Understanding the impacts of such factors on water resources vulnerability is essential for ensuring the sustainability of future water resources. In this study, a water resources sustainable index is built using a system dynamics model to assess the effects of different scenarios at the Kowsar dam basin in southwestern Iran where managing water resources is serious challenging due to periodic drought. Based on the baseline scenario, the total population, as well as total water demand, will increase and water supply will decrease throughout the simulated period. Therefore, the imbalanced supply-demand of water can cause the water system vulnerable. In this regard, water management policies should concentrate on the demand side of water to address the problem of water resource shortage in a good manner. Although pessimistic climatic conditions along with population growth put the water system in the worse situation of water availability, where the demand control policies likely help meet the increasing water demand. Compared to the pessimistic conditions, the water sustainability index improves in normal and optimistic conditions. The highest sustainability index was obtained after controlling water demand in optimistic weather condition. Consequently, the government should provide a context in which people learn to control their daily water consumption. Also, it suggests that we can conserve water resources in the agricultural sector with conservation policies.