Groundwater sustainability assessment framework: A demonstration of environmental sustainability index for Hanoi, Vietnam

There is mounting concern about how to support decision-makers in driving sustainable water resources management; science needs to support the decision-making process to promote evidence-based decisions. To this end, sustainability assessment is considered a useful technique, which provides enough information to assist management. This study proposed a groundwater sustainability assessment framework, which is developed from a regular sustainability assessment approach and analytical hierarchy process (AHP). In the proposed framework, the three main pillars (environmental, social, and economic) of the concept of sustainability were considered the three important sustainability criteria. Hence, we demonstrated the proposed framework for a Hanoi case study with focus on the environmental sustainability criterion. The concept of AHP was used to create the main sustainability components (the three criteria, associated with their aspects and indicators) of a hierarchy, which appropriately cover environmental sustainability issues of groundwater resources in the target area. Based on the available reliable data of the current problems in Hanoi, we proposed three main sustainability aspects (quantity, quality, and management) and, accordingly, selected their twelve environmental sustainability indicators. To determine a reasonable sustainability assessment, we considered a conventional linear and non-linear relationship between the indicators and the corresponding sustainability indices. As for the results from the Hanoi case study, the environmental sustainability indices obtained from using a combined linear and non-linear relationship case appropriately reflect the current situation, that is, the environmental sustainability assessment is close to reality. The sustainability indices of the quantity, quality, and management aspects of groundwater were appropriately assessed at acceptable levels, resulting in Hanoi being rated at the acceptable level in the final environmental sustainability index. The variability of the environmental sustainability indices indicated that the current groundwater abstraction networks are heavily concentrated in a few specific areas in Hanoi, which is not optimal for utilizing the rich natural recharge resources of the area. Improvement of the current poor groundwater quality and strict enforcement of environmental regulations are essential to enhancing the environmental sustainability and, more importantly, to drive Hanoi towards