<p>The future success of agriculture in arid and semi-arid areas globally will be highly dependent on the ability of farmers and agricultural systems to adapt to climate change. Most of these areas, though tremendously productive, suffer from the same limiting resource: water. As that resource becomes more scarce and availability more difficult to predict, water managers and farmers will be forced to implement new, creative solutions to water supply challenges. This anticipated exposure suggests that an improved understanding of agricultural adaptation to water stress in such areas is critical to successful outcomes in these regions under a changing climate. This work focuses specifically on the adaptation strategies employed by farmers, strategies which are determined by farmers’ assessment of their exposure and sensitivity to a stressor as well as their capacity to implement changes. This process of implementing change to limit vulnerability is broadly referred to as adaptation. </p> <p> This project focuses on the Eastern Snake Plain of southeastern Idaho as a case study in agricultural adaptation to increased water stress. The Eastern Snake Plain (ESP) is a diverse and productive agricultural basin in the inter-mountain region of the American West. The region’s primary products are potatoes, sugar beets, barley, and alfalfa, as well as a significant volume of livestock dominated by dairy cattle, and each of these products forms a significant share of the total US market for that crop. More than 74% of this agricultural land is irrigated, inextricably tying both the future of agriculture and the future of the Idaho economy to water in the state. In the mid-2000’s, legislators and water managers from across the plain came together to negotiate a new water rights settlement, now known as the Eastern Snake Plain Aquifer Comprehensive Aquifer Management Plan (CAMP). The negotiations came in response to years of litigation involving groundwater and surface water conjunctive management in the region, and the resulting plan was designed to accomplish three goals: stabilize reach gains in the lower Eastern Snake Plain, replenish Eastern Snake Plain Aquifer (ESPA) levels, and ensure sustainable water resources for agricultural, industrial, and domestic users across the basin. Though the water settlement was not directly caused by climate change, it is likely that water shortages will become more frequent under climate change, and this settlement represents a simulation of just such a shortage.</p> <p>Broadly, this work and the work of collaborators hope to understand adaptation and decision-making of groundwater farmers throughout the Eastern Snake Plain as they adapt to the on-average 12.9% reduction in water availability. This thesis is divided into three primary sections (Chapters 2, 3, and 4). </p> <p>Chapter 2 investigates tradeoffs in adaptation decision making, employing semi-structured interviews to learn more about tradeoffs as a framework for understanding adaptation more broadly. In particular, the work seeks to understand the types of tradeoffs present in ESP adaptation and when and how tradeoffs are implicitly or explicitly acknowledged. Findings indicate that tradeoffs occur both at the individual and regional scale and that shifts in crop patterns and irrigation water sourcing may have important implications for adaptation policy moving forward. </p> <p>Chapter 3 employs a household survey and statistical analysis to investigate the iterative and complex relationships between exposure, adaptive capacity, sensitivity, and vulnerability. As an early attempt to examine these relationships quantitatively in the context of US agriculture and water stress, the works focuses on laying out a clear theoretical and methodological framework for continued exploration of adaptation and vulnerability in this context. Findings indicate that under-theorized components of adaptive capacity like linking capacity and exposure to simultaneous stressors may play important roles in determining farmer vulnerability in the context of policy-induced water scarcity. </p> <p>Chapter 4 is designed to investigate and develop a novel tool for exploratory work in adaptation, examining the feasibility and predictive accuracy of an agent-based model of agricultural adaptation driven by social-psychological decision-making theories and parameterized using both secondary data sources and primary fieldwork. Findings indicate that such models may have the potential to produce well-informed macro-level patterns based on theoretically-informed micro-level inputs. This has important implications for the broader agent-base modeling community, and the work concludes with a call for further collaboration between agent-based modelers and social science theorists. </p> <p>Collectively, this work seeks to inform theory on agricultural adaptation and vulnerability, as well as explore the potential role of theoretically-informed agent-based modeling in investigating such dynamics. In doing so, it lays the groundwork for future exploration of these ideas in the Eastern Snake Plain and throughout the arid American West. </p>