Streamflow Partitioning and Transit Time Distribution in Snow-Dominated Basins as a Function of Climate

The Science

Several models (PRMS-PEST-SAS) were coupled and applied to the snow-dominated East River Watershed to explore changes in water budgets and seasonal and annual responses in the streamflow transit time distributions.

The Impact

This research was the first to apply the coupled PRMS-PEST-SAS modeling system to a large-scale (85 km2) snow-dominated watershed. Results provide insight into how variation of the water budget and streamflow transit time are responding to climate change in this alpine snow-dominated system.


The modeling results show that during the snowmelt period of the year, the East River released younger water during high storage periods across seasonal and annual timescales (an “inverse storage effect”). However, wet years also appeared to increase hydrologic connectivity, which simultaneously flushed older water from the basin. During years with reduced snowpack, flow paths were inactivated and snowmelt remained in the subsurface to become older water that was potentially reactivated in subsequent wet years. Dry years were found more sensitive to warming temperatures than wet years through marked increases in the fraction of inflow lost to evapotranspiration at the expense of younger water to increase the mean age of streamflow.

Principal Investigator(s)

Zhufeng Fang
Desert Research Institute


Work was supported by the U.S. Geological Survey through the National Institute of Water Resources under Grant/Cooperative Agreement No. (G16AP00196), and the Lawrence Berkeley National Laboratory’s WFSFA through the Office of Biological and Environmental Research, within the U.S. Department of Energy Office of Science under contract DE-AC02-05CH11231.


Fang, Z., Carroll, R., Schumer, R., Harman, C., Wilusz, D., Williams, K. “Streamflow partitioning and transit time distribution in snow-dominated basins as a function of climate.” Journal of Hydrology 570, 726–38 (2019). [DOI:10.1016/j.jhydrol.2019.01.029].