Advancing regional water supply planning to develop robust, adaptive, equitable, and cooperatively stable infrastructure investment and management pathways

Abstract

Globally, urban water utilities are challenged by increasingly severe droughts and growing water demands. In the United States (US), these challenges are compounded by increasing costs of new supply development and aging infrastructure that strain the budgets of local water utilities. Regional cooperation can help utilities face these challenges by improving the efficiency of existing water sources and exploiting economies of scale to reduce the capital cost of new infrastructure investment. When implemented using state-aware rule systems that trigger drought mitigation and infrastructure investment decisions, cooperative strategies have been shown to generate infrastructure investment and management policies that maintain robust performance across a broad array of future conditions. But regional cooperation also generates new challenges for water supply planning. Effective strategies must equitably balance the potentially divergent interests of regional partners, as regional conflict can destabilize partnerships, exposing utilities to new risks. The presence of uncertainty in water supply planning problems heightens these risks by masking sources of potential inequity and instability. These challenges motivate the need for new decision support frameworks to develop robust, equitable, cooperatively stable infrastructure investment and management policies. This dissertation presents new research that advances the development of actionable regional water supply management strategies. The first study introduces methodology for exploring robustness conflicts and measuring the impact of implementation uncertainty on water cooperative water supply portfolios. Applied to a system of four water utilities, this study shows that negotiation strategies can discover regional policies that balance robustness across a group of cooperating partners, but also finds that these policies are highly vulnerable to implementation uncertainty. These results further illustrate how delineating safe operating spaces allows utilities to avoid these vulnerabilities. The second study looks more deeply into the multi-actor dynamics of cooperative water supply planning by introducing Regional Defection Analysis, a new methodology for analyzing the cooperative stability of regional supply partnerships and mapping the power relationships within these systems. Regional Defection Analysis extends the existing DU Pathway Framework. Results from a system of three water utilities highlight how seemingly robust infrastructure investment policies may be vulnerable to cooperative instability, reveal power dynamics between regional partners and suggest methods of reducing conflict within cooperative agreements. The third study builds on Regional Defection Analysis by contributing DU Pathway_ERAS, further developing the DU Pathways framework to explicitly focus on the development of equitable, robust, adaptive and cooperatively stable infrastructure investment and management pathways. When applied to a six-utility regional infrastructure investment planning problem, DU Pathway_ERAS (1) reveals how a priori assumptions about performance priorities can lead to unintended consequences for regional equity, (2) illustrates how regional partners can utilize cooperative power to improve regional robustness, and (3) highlights how system vulnerabilities evolves over time.