Evaluating the ability of transformed urban agglomerations to achieve Sustainable Development Goal 6 from the perspective of the water planetary boundary: Evidence from Guanzhong in China.

Differences in water resource endowment and socio-economic development of transformed urban agglomerations (TUAs) lead to differences in the ability of cities to achieve Sustainable Development Goal 6 (SDG6), which inevitably underestimates the possibility of water crises. This study employs the water footprint (WF) and reduced water planetary boundary (WPB) as absolute environmental sustainability indicators and uses a drive-pressure-state-impact-response (DPSIR) framework to describe the spatio-temporal differences and evolutionary characteristics of the ability of a TUA to achieve SDG6. This study takes the Guanzhong urban agglomeration (GUA) in China as a case. The WF of GUA increased from 19.55 billion m3 to 23.44 billion m3 in 2007–2018, but it increased initially and then fell. The proportion of the ecological environment WF increased by 1.41%, which is in line with SDG6.4 and SDG6.6. However, WF is larger than WPB. The water deficit was within the interval of [6 billion m3, 23 billion m3]. The pressure subsystems in Tongchuan and Weinan were as high as 28.80%, and the response subsystems in Xi'an and Baoji had the highest weights of 33.79% and 25.84%, respectively. Thus, GUA is under severe water pressure. Causal chain relationships between the socio-economic activities of each city in the water resource system were not the same, reflecting a spatial difference in the ability to achieve SDG6. To this end, this study proposes the potential value and policy implications of reducing the differences in the ability of cities to achieve SDG6 to avoid water crises in TUAs. [Display omitted] ∙ Use DPSIR model to build a framework for water resources sustainability assessment. ∙Narrowing gap in ability of cities to achieve SDG6 can meet new water challenges. ∙Causal chain of human activities and water resources affects ability to achieve SDG6. ∙Water footprint larger than water planetary boundary indicates a water deficit. ∙Cross-regional compensation mechanism can realize sustainable use of water resources. [ABSTRACT FROM AUTHOR]