Sustainability analysis of single vs. multiple adaptation strategies in tackling the adverse impacts of climate change on groundwater resources using water-food-energy nexus approach

Research has shown that groundwater level has decreased in the last few decades worldwide. In future periods, due to global warming and the change in the amount and regime of precipitation, the intensity of groundwater level drop in various parts of the world will increase. This study aims to investigate both single and multiple adaptation strategies to obtain sustainable groundwater resources. At first, the system dynamics model of the Alborz province as the study area, which is located in the center of Iran and includes three aquifers, was developed considering socio-economic, hydrology, agriculture, and energy subsystems. Then, the system was calibrated during an observation period using behavior repetition and extreme conditions tests. Next, the temperature and precipitation data obtained from 16 AOGCM-AR6 models under the SSP2-4.5 scenario were downscaled in the region. The ensemble mean values of temperature and precipitation showed an increase of 1.8 degrees C in temperature and a 3.5% decrease in precipitation in the period of 2021 - 2050 compared to the 1985 - 2014 period. The introduction of downscaled climate scenarios to the developed system dynamics model revealed a sharp drop in the groundwater of the aquifers until 2050. Different adaptation strategies based on water demand management in the agricultural, domestic, and industrial sectors were determined for all three aquifers based on consulting with decision-makers and evaluated using the system dynamics model. Evaluating sustainability indices showed the insignificant effectiveness of each adaptation strategy individually for each aquifer. Meanwhile, the combination of adaptation strategies will not only increase the sustainability of the water systems of the region but will also cause the groundwater level of all aquifers to rise. The framework introduced in this research can be used in most surface and groundwater resource systems to determine the most efficient solutions to adapt to the effects of climate change.