Simulating the spatial distribution of snow pack and snow melt runoff with different snow melt algorithms in a physics based watershed model

Thursday, 18 December 2014: 10:50 AM
Michael L Follum1, Charles W Downer1 and Jeffrey D Niemann2, (1)Engineer Research and Development Center Vicksburg, Coastal and Hydrualic Laboratory, Hydrologic Systems Branch, Vicksburg, MS, United States, (2)Colorado State University, Fort Collins, CO, United States
The Gridded Surface Subsurface Hydrologic Analysis (GSSHA) is a fully distributed, physics based, continuous watershed simulator developed and applied by the US Army Engineer Research and Development Center (ERDC). By taking advantage of the inherent spatial and temporal variability contained in the model, we are able to simulate the effects of slope and solar shading due to topography, vegetation, and varying hydrometeorology with elevation, on snow accumulation and melt. Combined with vertical and lateral melt-water transport algorithms, we are able to simulate the spatial distribution of the snow pack over time and the melt water discharge at the Senator Beck Basin, a small (2.9 Km2) basin in southern Colorado. We simulate snow accumulation and melt at the basin using three different snow melt algorithms in the GSSHA model and compare model results to satellite-derived area maps, point snow water equivalent data, point soil moisture data, and streamflow at the basin outlet. Results indicate that energy balance based methods produce better results than temperature based methods.