This dissertation research will improve current understandings of regional adaptation to climate change, a problem increasingly recognized as critically important by scientists and policymakers. It will integrate climatology, hydrology, and decision analysis to address a current debate about the importance of risk and risk aversion in climate change assessments. Risk aversion (the desire to manage events so as to avoid risk), is common in human decision-makers, but to date modeling of water resources and climate change have implicitly assumed risk neutrality (indifference to risk). The proposed research will incorporate risk and risk aversion into an integrated assessment of climate change impacts and adaptation strategies in water resources in California's Central Valley. The analysis will proceed in four steps. First, an integrated hydrology and water operations simulation model will describe three basins in California's Central Valley. Second, re-sampling synthetic historical weather time series (and perturbing them based on downscaled GCM data) over many model runs will generate probability distributions for water supply reliability at each demand node in the model. Third, economic techniques for utility function elicitation will be used to determine the risk preferences of water organizations in the study basins. Combining these utility functions with probabilistic output from the hydrology model will allow estimation of expected utility. Finally, scenarios of management options for adapting to projected changes will be analyzed under different assumptions of emissions trajectories, allowing for comparison of the expected utility to each water organization under each modeled scenario. The result will be a clearer understanding of impacts and adaptation than existing studies.
The project will make contributions to the study of water resources in the fields of physical geography and risk analysis. First, it will take up theoretical challenges to the widespread assumptions by water planners that future climate will closely resemble that in recorded history. It will produce a method to more clearly articulate the hydrologic risks faced by water managers. Second, in the field of risk analysis, the research will challenge the implicit assumption of risk neutrality in the water resources and climate change literatures. Given that climate change will likely involve increased extreme events and uncertainty about water supply, its projected impacts will likely be significantly greater when risk aversion is explicitly acknowledged. By applying both risk and risk aversion to regional scale climate impacts assessment, this research will produce a set of products that are greater than the sum of the individual parts. The tools produced by this research will have direct application in this and other water resource systems. The hydrology/water operations model will be a more transparent, accessible tool than those that currently exist for modeling water operations in California. In the short term, the model will be useful for sensitivity analysis by stakeholders who currently lack access to such planning tools. In the longer term, the model will be connected with others to form a statewide representation that integrates new functionality, including a dynamic representation of physical hydrology appropriate for climate change assessment. Additionally, this general tool can be applied to topics ranging from environmental assessments to water supply reliability analysis. As a Doctoral Dissertation Research Improvement award, this award also will provide support to enable a promising student to establish a strong independent research career.
