Climate change has the potential to alter streamflow regimes, which has ecological, economic, and social implications. In the northeastern United States, it is unclear how climate change may affect the surface water supply, which is critically important in this densely populated region. NRS scientist John Campbell and collaborators have been evaluating the impact of climate change on streamflow at small gauged watersheds at the Hubbard Brook Experimental Forest in New Hampshire. These headwater streams are the source waters for larger rivers and therefore, may serve as an indicator for potential climate change effects. Campbell's research evaluates past long-term hydrologic data and modeled future streamflow through the end of the 21st century using several climate change scenarios. Preliminary results indicate that earlier snowmelt and the diminishing snowpack is advancing the timing and reducing the magnitude of peak discharge associated with snowmelt. However, there is little change in the overall quantity of streamflow because increases in precipitation offset increases in water loss via evaporation and plant transpiration. This study is improving our understanding of the hydrological consequences of climate change, and will begin to provide a foundation for sound future decision-making on climate change policy.