Hydrology and society: Phenomena emerging from the interactions and feedbacks between human and water systems

Water resources management and hydrological risk reduction require anticipation of emergent (unexpected or unintended) phenomena as fundamental dynamics of complex human-water systems. Explaining and characterizing these sociohydrological phenomena is a central focus of Panta Rhei–Everything Flows, the Scientific Decade of the International Association of Hydrological Sciences (2013-2022). Here we use System Dynamics’ archetypes to describe and classify socio-hydrological phenomena emerging from nonlinear interactions between human and water systems. Archetypes illustrate dynamic behaviours that are frequently observed across (seemingly) different systems, contexts or problem settings. They include intended or unintended actions and reactions with explicit recognition of delays in reaction times. Reinforcing (or positive) and balancing (or negative) feedback loops and system boundaries are key elements for describing archetypes. In the study of human-water systems, the most common archetypes are Limits to Growth, Fixes that Backfire, Success to the Successful, and Tragedy of the Commons. Using system archetypes to generalize the phenomena in coupled human-water systems allows for the comparison among case studies along with the integration of multiple dimensions, thereby contributing to the development of new theories which provide common causes and explanations. We first present several classes of sociohydrological phenomena that have been explored over the past decade, and then discuss their role in explaining the dynamics of human-water systems. Finally, we engage with the implications for integrated water resources management, hydrological risk reduction, and water governance.