Submitted to: American Geophysical Union
Publication Type: Abstract Only
Publication Acceptance Date: 9/7/2000
Publication Date: N/A
Technical Abstract: Frozen soil can result in significant runoff and erosion events from otherwise mild rainfall or snowmelt events. However, most hydrologic models, including most snowmelt runoff models, include no provisions for soil freezing and thawing, and thus cannot address these extreme, yet common, hydrologic events. The Simultaneous Heat and Water (SHAW) model represents one of the more detailed models of snowmelt and soil freezing and thawing. However its complex and iterative solution requires a modest amount of CPU runtime which inhibits coupling the model with distributed hydrologic models to compute the energy and water dynamics over numerous grid points across a watershed. Methods to simplify the model and reduce runtime without a large reduction in accuracy were explored and tested using data from three rangeland field sites: a lower and an upper elevation site on the Boise Front outside Boise, Idaho; and a mid-elevation site in the Reynolds Creek Experimental Watershed in the Owyhee Mountains approximately 80 km southwest of Boise. Preliminary results suggest that simplification of the model can result in significant runtime reductions with only slight changes in simulated soil freezing, snowmelt and runoff.