Evaluating water quality ecosystem services of wetlands under climatic change

Potential hydrologic effects of climate change have been assessed extensively; however, possible impacts of changing climate on in-stream water quality have received little study. We as- sessed potential effects of climate change on water quality under present-day and varied future wet- land extent in the mountainous Sprague River watershed, Oregon, USA. We utilized the hydrologic model Soil and Water Assessment Tool (SWAT) forced with distinct climate scenarios derived from downscaled General Circulation Models to assess hydrologic model outputs of flow, sedi- ment, phosphorus and nitrogen. Model outputs were characterized by projection ensembles under present-day wetland extent and varying future wetland scenarios for the mid-21 st century. Results indicate seasonal shifts in magnitude and timing of streamflow peaks and associated loads of sedi- ment and nutrients, and provide insight into the role of wetlands in watershed-scale water quality under uncertain future climate.