Adaptation of Water Resources System to Water Scarcity and Climate Change in the Suburb Area of Megacities

The projection of climate change impacts can be very crucial for water resources planning and management. Hashtgerd plain is an immigrant destination due to socio-economic development and its proximity to the Tehran metropolis. The population growth has led to more water demand, resulting in excessive utilization of groundwater resources and water shortages in the agricultural sector. The water shortage and climate change in Hashtgerd plain could lead to more severe water crisis in the future. Therefore, this study aimed to provide adaptation strategies for minimizing the negative effects of climate change by taking into account the interaction between different sub-systems in Hashtgerd plain during 2020–2049 period. In order to assess the climate change impacts, the output of 19 AOGCMs models was used under RCP2.6, RCP4.5 and RCP8.5 emission scenarios. A comprehensive model was developed based on the system dynamics theory to investigate the interactions of water resources, agriculture, and socio-economic sub-systems and were used to investigate the impacts of climate change and evaluate various adaptation strategies on different sub-systems of the region. The simulation results showed the negative effects of climate change will intensify the water shortage in Hashtgerd Plain. The agricultural sector will be more vulnerable to climate change than the domestic and industrial sectors. The results of various policies showed that improving water use efficiency coupled with reducing the cultivation of high-consumption crops and changing the cropping pattern towards lower water requirement plants can effectively minimize the adverse impacts of climate change on water shortages in agriculture.