Abstract
Regional climate change impacts show wide range of variations under
different levels of global warming. Watersheds in the northeastern
region of United States (NEUS) are projected to undergo most severe
impacts from climate change in the forms of extreme precipitation
events, floods and drought, sea level rise etc. As such, there is high
possibility that hydrologic regimes in the NEUS may get altered in the
future which can be absolutely devastating for managing water resources
and ecological balance across different watersheds. In this study,
therefore, we present a comprehensive impact analysis using different
hydrologic indicators across selected watersheds in the NEUS under
different thresholds of global temperature increases
(1.50C, 2.00C and
3.00C). Precipitation and temperature projections from
fourteen downscaled GCMs under RCP8.5 greenhouse gas concentration
pathway are used as inputs into a distributed hydrological model to
obtain future streamflow conditions. Overall, the results indicate that
majority of the selected watersheds will enter into a wetter regime
particularly during the months of winter while flow conditions during
late summer and fall indicate a dry future under all three thresholds of
temperature increases. The estimation of time of emergence of new
hydrological regimes show large uncertainties under
1.50C and 2.00C global temperature
increases, however, most of the GCM projections show strong consensus
that new hydrological regimes may appear in the NEUS watersheds under
3.00C temperature increase.