Volume-Driven and Flow Control Approach to Optimizing Equity in Intermittent Water Supply Systems

Over 1.3 billion people worldwide are serviced by intermittent water supply (IWS) systems, which are characterized by their inability to provide continuous water to consumers for 24 h a day. Consumers in IWS systems often rely on private storage tanks as a coping mechanism during periods without water access. Although these tanks can improve supply reliability, they also worsen existing inequity in water access, where some consumers have greater access to water than others. This research introduces a simulation–optimization framework that integrates volume-driven demand into hydraulic simulations in order to account for the utilization of private storage tanks in IWS systems. Bayesian optimization is utilized to determine a flow control schedule that maximizes the local supply and global equity amongst consumers. The proposed approach is applied to an IWS system, where we explore the mechanisms through which the disparity in hydraulic conditions across the network creates inequity in water access. The results reveal a hierarchy in supply amongst the consumers that dictates the degree to which consumers have access to water. While flow controls can offset some of the global disparities, the local supply hierarchy is maintained through micro-level consumer behavior that a partially controlled system cannot fully override. This work underscores the importance of the interplay between local consumer behavior and global supply equity and provides insights into the mechanisms behind supply inequity.