Adaptation to climate change impacts on California water resources

In California, as many other snowmelt dominated regions in the world, increases in the temperature levels caused by climate change will modify the current hydrologic conditions, reducing the amount of precipitation falling as snow and accelerating the snowmelt process. These two effects will amplify the current disparity of when water is needed and when water is available, creating a need to explore different avenues to adapt to these projected changes.; This research continues a number of previous studies, introducing however, new perspectives and methods on the study of climate change impacts and adaptation to these impacts using two case studies. These case studies represent two water resources systems located in California's Sierra Nevada Mountains. One is a high elevation hydropower system: the Upper American River Project (UARP) operated by the Sacramento Municipal Utility District. The second is a low elevation water resources system, the Merced River Basin located in the San Joaquin Valley.; These two systems are different in two key aspects. A high elevation system such as the UARP has lower storage capacity but fewer operational constraints and objectives as compared to a lower system such as the Merced River Basin. It is the combination of these two factors that will define the degree of adaptation capacity to climate change impacts. It is this degree of adaptation capacity what I explored in the first case study, focusing on the effects that both changes in the average and extreme (e.g. floods) hydrologic conditions have on system operations.; The Merced River Basin is a more complex system. The number of stakeholders and contending water use objectives increase for a lower elevation basin. In a system like this there is also the need to include surface and groundwater as a source of water for the system. In this second study I developed new optimization methods to explore the optimal use of water (including groundwater) under historical and future hydrologic conditions. These methods, derived from Stochastic Dynamic Programming, allow the explicit representation of climate change uncertainty and the exploration of different types of adaptation strategies to climate change: physical, operational and institutional changes.