CR 66:211-228 (2015)  -  DOI: https://doi.org/10.3354/cr01348

ABSTRACT: The Susquehanna River Basin (SRB) lies in the northeastern United States and contains a mosaic of wetlands that are susceptible to future climate change. This study develops a coupled surface–subsurface modeling framework to assess the prospects for the SRB wetlands under modified hydrologic processes induced by climate change. We selected 7 watersheds ranging in size from 163 to 902 km², representing the major landscapes of the SRB. We explored the broad spatial and temporal patterns across these watersheds between climate and wetland water levels by applying a coupled surface–subsurface model: Penn State Integrated Hydrologic Model (PIHM) with 7-yr hourly weather records from the North American Land Data Assimilation System. In the model calibration, we employed both streamflow and the spatial distribution of wetlands to constrain the model parameters. The possible effects of climate change on wetland hydrology were investigated by creating historical and future climate scenarios based on the output of one global climate model from Phase 3 of the Coupled Model Intercomparison Project (CMIP). We selected the best climate model based on historical performance to force the PIHM simulation of historical and future scenarios. The hydrologic scenarios suggested that water tables would fall, with greater declines in upland regions than in wetland areas. A key result of this study is that a high-resolution spatial and temporal model can resolve the heterogeneous wetland dynamics in the context of distributed mesoscale watershed modeling.

KEY WORDS: Climate change impacts · GCM · Spatial patterns · Watershed modeling · Water table · PIHM · Wetland · Susquehanna River Basin