Report on watershed modeling conducted in 20 large, U.S. watersheds to characterize the sensitivity of streamflow, nutrient (nitrogen and phosphorus), and sediment loading to a range of plausible mid-21st century climate change and urban development scenarios. The study also provides an improved understanding of methodological challenges associated with integrating existing tools (e.g., climate models, downscaling approaches, and watershed models) and data sets to address these scientific questions. Results provide an improved understanding of the complex and context-dependent relationships between climate change, land-use change, and water resources in different regions of the nation. Results indicate that in many locations future conditions are likely to be different from past experience. Figures and tables. This is a print on demand report.