Legal coordination and governance approaches for transboundary water resources management in the Greater Bay Area

The Guangdong–Hong Kong–Macao Greater Bay Area (GBA), a major Chinese economic hub, faces growing water governance challenges stemming from transboundary geography, uneven resource distribution, and differentiated administrative systems under the “one country, two systems” framework. Although operating under unified state sovereignty, the coexistence of three autonomous legal systems generates a quasi-international governance structure that complicates coordinated water management. Divergent hydrological conditions, development priorities, and regulatory standards across Guangdong, Hong Kong, and Macao further heighten institutional fragmentation. Drawing on an integrated theoretical framework combining polycentric governance, multi-level governance, hydro-hegemony, and multi-track water diplomacy, and through a brief comparison with the Rhine River regime, this study demonstrates that the GBA’s institutional complexity differs fundamentally from traditional international river basins. While infrastructure projects have alleviated supply constraints, fragmented legal authority and asymmetrical power relations remain structural barriers. The findings suggest that improving water governance in the GBA requires gradual legal harmonization through existing coordination mechanisms, technological innovation for water efficiency, and expanded participatory pathways. Such reforms are essential not only for environmental sustainability but also for achieving the GBA’s broader objectives of green industrial transformation, wetland restoration, and climate resilience. The study offers transferable insights for other metropolitan regions confronting transboundary resource governance under conditions of constitutional pluralism.