Securing drinking water resources for a coastal city under global change: Scientific and institutional perspectives

Abstract

Most urbanized coastal cities lack fresh water resources and rely on water supply from adjacent inland watersheds. Numerous threats, including global climate change and various human activities, affect both the quantity and quality of fresh water available. Here we carried out a case study of Xiamen, a coastal city in subtropical China. Long-term data analysis showed the increasing floods and droughts that are the expected main impacts of climate change on water quality and quantity. Increasing eutrophication and harmful algal blooms in recent decades threaten water quality in Jiangdong reservoir, which supplies raw water to Xiamen and other coastal areas. In addition to excessive manganese (Mn) in surface water, other potential threats to water quality and human health include various emerging contaminants; these threats have all been scientifically detected but are beyond the scope of routine water-monitoring programs. Based on lessons learned from water supply management initiatives currently in progress, we proposed a conceptual framework for “source-to-tap” integrated water management in an attempt to secure clean and safe water supply. Long-term monitoring and research, adaptive management and actions to reduce nutrients and other pollutants loading are vital to protect water sources, and measures to adapt to climate change should be considered to achieve these goals. Institutional enablers for transboundary and cross-sector management were also suggested: enacting integrated water policies, developing an ecological compensation policy, authorizing the management institution, improving the incentive mechanism of cross-border compensation and transfer payments considering environmental responsibility, and encouraging multiple-stakeholder involvement.