Conjunctive Use and Other Adaptation Strategies to the Impacts of Climate Change in California Water Resources

There is a growing evidence of that climate change could potentially affect California hydrology and water resource systems. Projections of these climate change conditions imply with high certainty increases in temperature and the associated earlier timing of snowmelt runoff, however projections of changes in precipitation and the associated water available are less certain, some studies showing higher levels of precipitation while others show drier conditions. Is it possible with this knowledge to design adaptation strategies that could be used to mitigate the impacts associated with climate change? And when should these strategies be implemented? Those are some of the questions we answer in a case study of Merced River Basin operations. We approached this problem using an optimization technique known as Sampling Stochastic Dynamic Programming which allows the derivation of reservoir and aquifer operating rules for the considering non-stationary hydrologic conditions such as those associated with climate change. The alternatives we explore follow into three categories: operational changes (changing flood control rules to accommodate earlier timing of inflows); infrastructure changes (increasing storage capacity to accommodate increasingly varying reservoir inflows) and; institutional changes (conjunctive use institutional framework which increases the potential for artificial recharge and a better handling of changing in timing of hydrologic conditions).