The project aimed to use existing models and data to understand how wildfires (number, size, and location) and land-use change will affect watersheds, and therefore water supply, under current conditions and future climates (through 2050) in the western U.S. The projected changes in temperature and precipitation are expected to affect water supply in two major ways: 1) decreased water availability, and 2) increased risk to watersheds via loses from fire. As the western population is projected to grow by 310 million people by 2100, this will potentially increase demand for diminishing supplies if housing growth occurs in rangelands or forested lands. Understanding watershed vulnerabilities due to changing climate, fire regime, and population pressures is important to managers, and more importantly, to human well-being. Because changes from climate and population pressures cannot be altered, knowing which watersheds are currently, and will be in the future, ranked as highly vulnerable will enable proactive management of water and fuels to most effectively reduce the potential impact by wildfire.