Identifying Actionable Compromises: Navigating Multi-City Robustness Conflicts to Discover Cooperative Safe Operating Spaces for Regional Water Supply Portfolios

Abstract

Regional cooperation among water utilities can improve the robustness of urban water supply systems to challenging and deeply uncertain futures. Through coordination mechanisms such as water transfers and regional demand management, water utilities can improve the efficiency of resource allocation and delay the need for new infrastructure investments. Though cooperation provides utilities with the potential for reduced cost strategies for improving the reliability of their services, two important challenges are worthy of careful consideration. First, regional utilities often have to navigate robustness conflicts stemming from potential asymmetries in their risk exposure, demand dynamics, and the availability of supply resources. Second, successful implementation of candidate compromise water portfolios requires that cooperating utilities understand their operational tolerances to deviations from the recommended regional actions (“imperfect implementation”). This study contributes a framework for identifying compromises across regional robustness conflicts and quantifying tolerances to implementation uncertainties. The framework is demonstrated on a system of four interdependent but institutionally independent water utilities in the Research Triangle region of North Carolina that are confronting robustness conflicts given asymmetries in their vulnerabilities to growing demands and hydroclimatic uncertainties. Our findings highlight that seemingly balanced compromise management strategies can yield significant and potentially surprising unintended consequences that could degrade regional cooperation. Moreover, asymmetries in regional robustness can be amplified with modest deviations from their agreed upon actions. Results of this analysis are broadly applicable to water supply regionalization as a global challenge and provide insights for discovering robust compromises and safe operating spaces for multi-actor water supply systems.