UC Irvine

As global populations grow and climate becomes more extreme, cities in drought prone regions of the world such as South East Australia are faced with escalating water scarcity and security challenges. Approaches geared towards addressing these challenges are diverse, and detecting “success” against background climate variability is difficult. Here we use 72 years of urban water consumption data from Melbourne, Australia, a city that recently overcame a 12 year “Millennium” drought, to 1) evaluate the utility of wavelet-based approaches for deconstructing climatic and anthropogenic drivers of urban water demand and 2) assess the relative contribution of various water saving strategies to overall demand reduction during the Millennium Drought. Our analysis points to conservation behavior as a dominant driver of municipal water savings (~69%), followed by non-revenue water reduction (~29%), and potable substitution with alternative sources like rain or recycled water (~3%). Demand exhibited both climatic and anthropogenic signatures, with temperature and rainfall impacting consumption significantly at all frequencies except 0.09-0.2 cpy. Residual patterns in demand (after removing climate effects) mapped to anthropogenic controls like outdoor water restrictions, which damped seasonal variability in consumption during the Millennium Drought, and changing technologies/social norms, which impacted consumption at sub annual frequencies, particularly from 1960-1990.