Authors: Madison Muxworthy – University of Utah
Title: Snow to Flow: Coupling iSnobal-HRRR and Sac-SMA in the Upper Colorado River Basin
Presentation Type: Poster
Abstract: Snowmelt is the primary source and driver of hydrology in many watersheds across the Western United States. Accurately quantifying snowmelt magnitude and timing is essential for predicting runoff to support downstream water demand and other hydrologic applications. With increasing variability water managers are assessing the usefulness of process-based models to complement index-based forecasting approaches, including the distributed snowpack mass and energy balance model, iSnobal. Here, we run iSnobal over the Yampa River basin (19,800 km2), located within the Upper Colorado River Basin (UCRB) for three consecutive water years (WY22 – WY24). We couple it with Sacramento Soil Moisture Accounting Model (Sac-SMA) to assess runoff from snow surface water input. By coupling iSnobal — forced with the High-Resolution Rapid Refresh (HRRR) weather model and informed by remotely sensed snow albedo— with Sac-SMA, this research aims to understand snowmelt-to-streamflow dynamics. Spatially distributed outputs from iSnobal are validated against in-situ sensor networks, manual snow observations, and lidar-mapped snow depth. Streamflow is assessed against measured discharge. Our findings aim to advance the incorporation of process-based snowmelt and hydrologic modeling in operational forecasting for snowmelt-dominated regions of the UCRB.