Paper No. JAWRA-12-0137-P of the Journal of the American Water Resources Association (JAWRA).
Modeling Discharge Rates Using a Coupled Modeled Approach for the Merced River in Yosemite National Park†
Version of Record online: 12 SEP 2013
© 2013 American Water Resources Association
JAWRA Journal of the American Water Resources Association
Volume 50, Issue 1, pages 153–162, February 2014
How to Cite
2014. Modeling Discharge Rates Using a Coupled Modeled Approach for the Merced River in Yosemite National Park. Journal of the American Water Resources Association (JAWRA) 50(1): 153-162. DOI: 10.1111/jawr.12124and ,
Discussions are open until six months from print publication.
- Issue online: 3 FEB 2014
- Version of Record online: 12 SEP 2013
- Manuscript Accepted: 18 JUN 2013
- Manuscript Received: 4 JUN 2012
- Planetary Skin Institute
- Merced River;
- Yosemite National Park;
- surface water hydrology;
- water discharge rates;
This study describes the application of the NASA version of the Carnegie-Ames-Stanford Approach (CASA) ecosystem model coupled with a surface hydrologic routing scheme previously called the Hydrological Routing Algorithm (HYDRA) to model monthly discharge rates from 2000 to 2007 on the Merced River drainage in Yosemite National Park, California. To assess CASA-HYDRA's capability to estimate actual water flows in extreme precipitation years, the focus of this study is the 2007 water year, which was very dry, and the 2005 water year, which was a moderately wet year in the historical record. Prior to comparisons to gauge records, CASA-HYDRA snowmelt algorithms were modified with equations from the U.S. Department of Agriculture Snowmelt-Runoff Model (SRM), which has been designed to predict daily streamflow in mountain basins where snowmelt is a major runoff factor. Results show that model predictions closely matched monthly flow rates at the Pohono Bridge gauge station (USGS#11266500), with R2 = 0.67 and Nash-Sutcliffe (E) = 0.65. By subdividing the upper Merced River basin into subbasins with high spatial resolution in the gridded modeling approach, we were able to determine which biophysical characteristics in the Sierra differed to the largest degree in extreme low-flow and high-flow years. Average elevation and snowpack accumulation were found to be the most important explanatory variables to understand subbasin contributions to monthly discharge rates.