A simple approach to evaluate future urban water demand under changing climate, population, and local policies in data-scarce regions

ABSTRACT Conceptual model illustrating three steps: estimating future PCC from temperature, combining contextual data for water demand components, and integrating both via the water balance equation to generate OPT and PES scenarios. Urban areas face increasing pressures due to climate change, population growth, and aging infrastructures. In this challenging context, municipalities need to foresee future water demand to plan investments and ensure a reliable water supply. This study proposes a simple model to estimate future urban water demand and applies it to a city located in Southern Quebec, Canada. The model estimates future water demand under different climate projections based on Coupled Model Intercomparison Project Phase 6 models by considering residential consumption alongside factors such as leakage rates, industrial-commercial-institutional consumption, demographic growth, and conservation strategies. A combination of regression and scenario-based analysis is used to explore water demand under different future conditions in this data-scarce study area. Population growth and rising temperatures, particularly under high radiative forcing scenarios, are projected to increase water demand. However, the study finds that implementing effective conservation measures, such as reducing system leakage and introducing conservation measures, can significantly offset these increases. The study underscores the importance of integrating climate, demographic trends, and behavioral factors into long-term water planning and puts forth a simple approach for municipalities to anticipate urban water demand based on limited available data to support strategic decision-making.