Rethinking water infrastructure system decision-making under human-induced uncertainty

Abstract

Water infrastructure system decision-making has long been challenged by uncertainty, but traditional decision framing centred on hydrological variability and climate-driven change is becoming increasingly inadequate. This is because water infrastructure systems are also shaped by adaptive human dynamics, such as evolving stakeholder behaviours, shifting political environments, advancing technologies, and transforming societal expectations. These dynamics are not only uncertain but endogenous, feeding back into system conditions in ways that cannot be adequately represented by conventional modelling assumptions. Consequently, future water infrastructure systems will not fail solely because environmental conditions exceed design assumptions, but because decision-support models fail to represent how people, institutions, and societies adapt in response to changing conditions and to the decisions themselves. This paper argues that human-induced uncertainty, defined as uncertainty arising from adaptive human behaviour and broader societal dynamics, demands a fundamental rethinking of how water infrastructure systems are modelled and managed. We distinguish human-induced uncertainty from natural uncertainty, examine its implications for both infrastructure system operation and planning, and identify critical gaps in current decision-support models. We then propose four key transitions required to build these models so that they are fit for a future shaped by coupled natural and human-induced change.