A Simple GIS-Based Snow Accumulation and Melt Model

A simple distributed snow accumulation and melt (SAM) model was developed for use in GIS-based hydrologic models. Snow drifting is simulated using observed wind speed and distributed snow drift factors, which are generated as a pre-processing step using the SnowTran-3d model. Snowmelt is simulated through a mass and energy balance applied to a single layered snow pack. Snow surface temperatures are simulated without the requirement of an iterative solution using a simple damping depth approach. The SAM model was applied to a 2 ha watershed in Troy, ID having three years of detailed snow water equivalent (SWE) measurements. Snow surface temperatures predicted by the SAM model using a fixed snow damping depth of 0.05 m showed good agreement with SHAW model predictions. The root mean square error (ERMS) between simulated and observed SWE across the site (10-46 mm) was consistent with and in some cases smaller than the ERMS at points where the maximum predicted SWE was fit to field observations (21-26 mm).