Xander Huggins , Tom Gleeson, Juan Castilla-Rho, Cameron Holley, Viviana Re, James S. Famiglietti

Groundwater is embedded in social and ecological systems but the complexity of these interactions is not well represented in conventional approaches to study and promote groundwater sustainability. We argue an important shift is necessary in groundwater sustainability thinking: towards prioritizing the functions of groundwater, and the services that make it a critical resource, and away from focussing on the resource in isolation. We articulate a new perspective for groundwater sustainability based around the concept of groundwater-connected systems—any system with dynamic relationships with groundwater, which can include ecological, social, and Earth systems. We draw from the emerging field of sustainability science and consider groundwater-connected systems to be specific forms of both social-ecological systems and complex adaptive systems. We argue this interdisciplinary systems-based perspective is necessary to connect existing research domains and paradigms, and provides additional concepts and tools from the established literatures of social-ecological systems and complex adaptive systems to improve how we study and manage groundwater-connected systems for resilience and sustainability. We provide a theoretical foundation for this perspective and discuss its practical implications which span data collection initiatives, scientific investigations, governance, and management approaches. Amidst calls for innovation in the groundwater field, we argue that embracing the groundwater-connected system perspective can underpin a methodologically pluralistic, interdisciplinary, community-wide, and bold new wave of groundwater research to better understand and promote groundwater sustainability in the complex systems groundwater is embedded within.