The Environmental Protection Agency (EPA) Office of Research and Development (ORD) National Center for Environmental Research (NCER), in cooperation with the EPA Global Change Research Program, announces a competition for projects supporting research into the consequences of climate change for U.S. water quality to support human and aquatic life uses. EPA is interested in the hydrologic and other watershed processes that affect water resources that may be altered by a changing climate. A better national scale understanding of the range of potential consequences of climate change will be useful both for fully accounting for the impacts of climate change and for developing regional adaptive strategies to reduce the risk of harmful impacts. The goal of this solicitation is to assemble modeling systems capable of capturing important linkages between regional climate drivers and terrestrial hydrologic systems and to apply these modeling systems to improve the overall understanding of the sensitivity of key water quality or aquatic ecosystem management targets to the types of climate changes anticipated over the next several decades.