Agricultural Water Resource Management in the Socio-Hydrology: A Framework for Using System Dynamics Simulation

Population growth, coupled with climate and social shifts, has resulted in a global phenomenon of water scarcity. Yet, the effect of social factors on water resources has been poorly studied. Hence, this study aimed to identify the key parameters in social systems that significantly impact hydrological system change and presents the best scenario for water management. The system dynamic (SD) approach was employed in this research to construct a combined framework of policies based on scenarios, which aimed to ensure social sustainability and coupled human-water systems. For this purpose, the SD model was simulated on the Gavshan Basin in the west of Iran for the long-term period 2020-2050. The results indicate that the water resources in the Gavshan Basin cannot meet the growth of the population. Meanwhile, about 20% of the water stored in the Gavshan Dam is not effectively used and flows out of the irrigation network as wastewater. The result of the sensitivity analysis showed that in scenarios 3 and 4, the policy of wastewater reuse in the agricultural sector significantly increases available water resources, has a major impact on water supply, and increases crop yields. These findings can be applied by policy-makers. Instead of making efforts only to change hydrological systems, policies need to first focus on socio-hydrology systems sustainability. It is suggested that national organizations' support should be implemented to prevent the adverse consequences of wastewater reuse in agriculture and reduce treated wastewater risks.