The high-elevation hydropower system in California is composed of more than 150 hydropower plants. The expected shift of runoff peak from spring to winter as a result of climate warming, resulting in snowpack reduction and earlier snowmelt, might have important effects on hydropower operations. Estimation of climate warming effects on such a large system by conventional simulation or optimization methods would be tedious and expensive. Employing optimization and cooperative game theory methods, this book presents a novel approach for modeling large hydropower systems and deriving climate change adaptation strategies for California.