A socio-hydrological model for assessing water resource allocation and water environmental regulations in the Maipo River basin

Overuse of water resources has led to serious ecological degradation in most river basins. However, there is little processed-based understanding of the dynamic feedback between management decisions from different sectors in river basins and their resultant socio-economic and ecological outcomes. This study developed a sociohydrological model to track the evolution of water used for socio-economic and ecological uses and to simulate the response of water resource allocation and water environmental regulations to the resulting economic and ecological outcomes. It was applied in the Maipo River basin, Chile, from 1990 to 2019. The results show that this model successfully simulated water resources allocation and water environmental regulations over time. Water environmental regulations showed a strongly linear responsive behaviour to observed accumulated ecological degradation. Results also show that the observed decrease in water resource allocation for economic uses was influenced by increasing agricultural economic benefits and accumulated ecological degradation. It is suggested that environmental regulations should be stronger, synchronized and coordinated with water resources allocation decisions to revert the increasing ecological degradation. This socio-hydrological model, with revision into different contexts, could be used to assess integrated water resources and water environmental management in other river basins.