- Discussions around adapting water management systems to climate change often express the need to increase the flexibility and adaptive capacity of current systems, and to implement robust strategies going forth. While these topics lie at the center of many climate change discussions, transforming adaptation recommendations into tangible tools and information used in decision-making has proven difficult. The climate adaptation literature lacks sufficient concrete examples of how water managers can assess the ability of current systems to perform under climate change and make decisions regarding potential adaptation strategies. In this dissertation, I outline a set of complimentary methods for water managers to assess the climate risk of current systems and potential management strategies. Throughout this process, I attempt to clarify and redefine climate terminology in terms of water resources management, with a particular emphasis on the term, flexibility. The developed climate assessment methods place emphasis on addressing the nonstationary, uncertain nature of climate change and how this conflicts with traditional water management decision-making methods that assume stationarity.
Within the climate adaptation literature, flexibility is one of the least rigorously explored terms. Very little work has examined what exactly it means to have a flexible water management system, what makes one system more flexible than another, or the extent to which flexibility increases adaptive capacity. In Chapter 2, I review flexibility literature and apply relevant flexibility concepts from other sectors to flood management systems. Based on this work, I present a methodology for assessing the flexibility of the structural and non-structural components of water systems using original indicators developed in the categories of: slack, redundancy, connectivity, adjustability, and compatibility/ coordination. I then apply this methodology to assess the ability of four proposed flood management strategies to increase the flexibility of the Sacramento River, CA flood management system (Chapter 3).
In the second portion of this dissertation, I demonstrate a bottom-up climate risk assessment that tailors available climate information to a decision regarding flood management in the American River basin, CA (Chapter 4). Using historic data and available models, I begin by evaluating the sensitivity and vulnerability of the flood management system to changes in climate. In order to incorporate some of the uncertainty associated with General Circulation Model (GCM) projections in the impact assessment, I use Bayesian methods to stochastically generate thousands of flood frequency parameters representing a plausible range of future flood conditions. Lastly, I assess the robustness of proposed management strategies in terms of their ability to meet flood risk and cost-effectiveness thresholds under a large portion of the plausible future conditions.
The studies presented in this dissertation provide water managers with examples of how to apply climate adaptation terms to on-the-ground water systems. I outline example evaluation techniques for a collection of related adaptation terms, in particular: flexibility, adaptive capacity, sensitivity, vulnerability, and robustness. While the example case studies are located in California, USA, the methodological basis used to assess climate risk, has broad applicability and can be adapted and applied to other water systems around the world.