As adaptation becomes more tightly integrated into the range of responses to climate change, understanding how knowledge of climate change impacts and vulnerabilities can be effectively used is essential both to direct research and to support action. This article reviews literature along an intellectual transect from knowledge of climate impacts on water systems to the influence of that knowledge on adaptation responses. We discuss scientific evidence for changing hydroclimatic regimes, methods for translating climatic information into results relevant to adaptation, uncertainties in these results, methods for addressing uncertainty via adaptation processes, challenges and opportunities for knowledge development and transfer, and sociopolitical factors that enable or hinder the use of knowledge. Challenges remain in developing and applying methods for identifying and reducing underlying vulnerabilities and reliably connecting technical knowledge of climate impacts with local needs remains an unsolved problem. But new decision-making methods and the potential to learn from analogous water management situations provide hope for near-term progress.

In many areas of the world, groundwater resources are increasingly stressed, and unsustainable use has become common. Where existing mechanisms for governing groundwater are ineffective or nonexistent, new ones need to be developed. Local level groundwater governance provides an intriguing alternative to top-down models, with the promise of enabling management to better match the diversity of physical and social conditions in groundwater basins. One such example is emerging in California, USA, where new state law requires new local agencies to self-organize and act to achieve sustainable groundwater management. In this article, we draw on insights from research on common pool resource management and natural resources governance to develop guidelines for institutional design for local groundwater governance, grounded in California’s developing experience. We offer nine criteria that can be used as principles or standards in the evaluation of institutional design for local level groundwater governance: scale, human capacity, funding, authority, independence, representation, participation, accountability, and transparency. We assert that local governance holds promise as an alternative to centralized governance in some settings but that its success will depend heavily on the details of its implementation. Further, for local implementation to achieve its promise, there remain important complementary roles for centralized governance. California’s developing experience with local level groundwater management in dozens of basins across the state provides a unique opportunity to test and assess the importance and influence of these criteria.