Sensitivity of streamflow, nutrient and sediment loads to potential climate change and urban development in 20 U.S. watersheds
Abstract
There is growing concern about the potential effects of climate change on water availability and quality. Effects will vary in different locations depending on the specific types of change that occur together with differences in watershed land-use, physiographic setting and human use and management of water. This study addresses gaps in our knowledge of the sensitivity of U.S. streamflow, nutrient (N and P) and sediment loading to potential future climate change and potential interaction of climate change with urban and residential development in different regions of the U.S. Watershed modeling was conducted in 20 large (15,000-60,000 km2) watersheds using the Soil and Water Assessment Tool (SWAT) model. Climate change scenarios are based on dynamically downscaled (50x50 km2) output from four of the GCMs used in the Intergovernmental Panel on Climate Change (IPCC) 4th Assessment Report for the period 2041-2070 archived by the North American Regional Climate Change Assessment Program (NARCCAP). Urban and residential development scenarios representative of mid-21st century for each of the 20 study watersheds were acquired from EPA's national-scale Integrated Climate and Land Use Scenarios (ICLUS) project. Here we present selected results comparing simulations across all 20 watersheds. These results provide an overview of the response to climate change in different regions of the U.S., and illustrate differences in the sensitivity of different streamflow and water quality endpoints to a range of potential future climate and urban development scenarios. For most locations and endpoints the range of simulated responses to all scenarios includes increases and decreases relative to historical conditions. At the spatial scale of these simulations (HUC-8) projected mid-21st century changes in developed land were never more than a few percent of the total watershed area. The simulated watershed response to climate change was thus greater in all locations than from urban and residential development. Ongoing analyses address the relative effects of climate change and urban development at smaller spatial scales, and the influence of methodological choices such as different hydrologic models and downscaled climate scenarios on the variability of watershed simulations.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2012
- Bibcode:
- 2012AGUFM.H43F1422J
- Keywords:
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- 0496 BIOGEOSCIENCES / Water quality;
- 1807 HYDROLOGY / Climate impacts;
- 1847 HYDROLOGY / Modeling;
- 1860 HYDROLOGY / Streamflow