Climate Change Impacts on U.S. Streamflow and Water Quality

Abstract:

Climate change with intensifying extreme events will likely have serious consequences on the terrestrial hydrology, ecosystem production, and water quality in the U.S. It is in pressing need to assess these consequences by a system approach that integrates key interactive processes, major pollutant sources, and comprehensive climate projections at fine spatial and temporal resolution. This study develops and applies a state-of-the-art system that integrates a global climate-chemical transport model with a high-resolution regional climate-hydrology-air quality-water quality model over North America to predict the interactive dynamical, physical and biogeochemical processes that govern the movement of water and pollutants in the air and on land (surface, subsurface, streams, plants, human). It will show that the system well captures the observed geographic distributions and seasonal-interannual variations of streamflow and water quality (nitrogen) over the U.S. Diagnostic analyses indicate that major water quality episodes are associated with large climate anomalies, especially extreme precipitation events. The system also projects the impacts on the U.S. water resources (streamflow and water quality) of climate change to 2050, which will be presented along with changes in extreme events, CO₂ fertilization, and atmospheric depositions. The resilience and sustainability of future U.S. water resources will also be discussed.