Physically Based Hydrology Model in a Snowmelt-Dominant Watershed

Abstract:

Snowmelt-runoff process exibits different hydrological features compared to the rainfall runoff. This paper implements a temperature index snowmelt method to a physically based hydrology model. The model is applied to the Senator Beck site where the recent NASA SnowEx snow field campaign was conducted in 2016-2017. A 10 m resolution DEM is used to extract the watershed along with soil hydraulic properties and land cover to drive the snowmelt-runoff model in overland and channel grid cells. The physically based land surface watershed model, the Colorado State University TREX is modified to handle snowmelt as a rainfall when the air temperature is above zero degree celcius in the 10 m grid at each time step. The weather forcing dataset was extracted from a nearby USDA SNOTEL station, named the Red Mountain. With a support from Colorado Avalanche Center, the streamflow observation at the outlet of the Senator Beck watershed is compared with the modeled streamflow at the same outlet location. This study will further to equip an energy balance approach to determine the snow temperature at each time step, and a single snow layer will be modified to have a multi-layer scheme which is relevant to the represent a micro-structure of the layered snow.