Paper No. JAWRA-11-0117-P of the Journal of the American Water Resources Association (JAWRA). Discussions are open until six months from print publication.
Projections of 21st Century Sierra Nevada Local Hydrologic Flow Components Using an Ensemble of General Circulation Models1
Article first published online: 10 AUG 2012
© 2012 American Water Resources Association
JAWRA Journal of the American Water Resources Association
Volume 48, Issue 6, pages 1104–1125, December 2012
How to Cite
Ficklin, D. L., Stewart, I. T. and Maurer, E. P. (2012), Projections of 21st Century Sierra Nevada Local Hydrologic Flow Components Using an Ensemble of General Circulation Models. JAWRA Journal of the American Water Resources Association, 48: 1104–1125. doi: 10.1111/j.1752-1688.2012.00675.x
- Issue published online: 3 DEC 2012
- Article first published online: 10 AUG 2012
- Received September 26, 2011; accepted April 23, 2012.
- hydrologic cycle;
- climate variability/change;
- surface water hydrology;
- snow hydrology;
Abstract: Sierra Nevada snowmelt and runoff is a key source of water for many of California’s 38 million residents and nearly the entire population of western Nevada. The purpose of this study was to assess the impacts of expected 21st Century climatic changes in the Sierra Nevada at the subwatershed scale, for all hydrologic flow components, and for a suite of 16 General Circulation Models (GCMs) with two emission scenarios. The Soil and Water Assessment Tool (SWAT) was calibrated and validated at 35 unimpaired streamflow sites. Results show that temperatures are projected to increase throughout the Sierra Nevada, whereas precipitation projections vary between GCMs. These climatic changes drive a decrease in average annual streamflow and an advance of snowmelt and runoff by several weeks. The largest streamflow reductions were found in the mid-range elevations due to less snow accumulation, whereas the higher elevation watersheds were more resilient due to colder temperatures. Simulation results showed that decreases in snowmelt affects not only streamflow, but evapotranspiration, surface, and subsurface flows, such that less water is available in spring and summer, thus potentially affecting aquatic and terrestrial ecosystems. Declining spring and summer flows did not equally affect all subwatersheds in the region, and the subwatershed perspective allowed for identification for the most sensitive basins throughout the Sierra Nevada.