Advancing Regional Water Supply Management and Infrastructure Investment Pathways That Are Equitable, Robust, Adaptive, and Cooperatively Stable

Regionalization approaches-where utilities in close geographic proximity cooperate to manage drought risks and co-invest in new infrastructure-are increasingly necessary strategies for leveraging economies of scale to meet growing demands and navigate financial risks. However, regionalization also brings new challenges to water supply planning. Successful regionalization policies must equitably balance the interests of multiple partners while navigating power relationships between regional actors. In long-term infrastructure planning contexts, this challenge is heightened by the evolving system-state dynamics, which may be fundamentally reshaped by infrastructure investment. This work introduces Equitable, Robust, Adaptive, and Stable Deeply Uncertain Pathways (DU PathwaysERAS), an exploratory modeling framework for developing regional water supply management and infrastructure investment pathways. DU PathwaysERAS provides an integrated framework for stakeholders to evaluate the equity of policy outcomes across cooperating partners and explore regional power relationships within cooperative infrastructure policies. To capture the time-evolving dynamics of infrastructure pathways, DU PathwaysERAS features new tools to measure the adaptive capacity of pathway policies and evaluate time-evolving vulnerability. We demonstrate our framework on a six-utility water supply partnership seeking to develop cooperative infrastructure investment pathways in the Research Triangle, North Carolina. Our results indicate that commonly employed framings of robustness can have large and unintended adverse consequences for regional partnerships. Results further illustrate that regional and individual vulnerabilities are highly interdependent and emphasize the need to limit counterparty risks through carefully designed cooperative agreements. Beyond the Research Triangle, these results are broadly applicable to cooperative water supply infrastructure investment and management globally.