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ARS Home » Plains Area » Temple, Texas » Grassland Soil and Water Research Laboratory » Research » Publications at this Location » Publication #143729
Title: DEVELOPMENT OF A SNOWFALL--SNOWMELT ROUTINE FOR MOUNTAINOUS TERRAIN FOR THE SOIL WATER ASSESSMENT TOOL (SWAT)

Author
item FONTAINE, T - SD SCHOOL OF MINES & TECH
item CRUICKSHANK, T - UTS DIV OF AIR QUALITY
item Arnold, Jeffrey
item HOTCHKISS, R - WASHINGTON STATE UNIV

Submitted to: Journal of Hydrology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/14/2002
Publication Date: 2/14/2002
Citation: FONTAINE, T.A., CRUICKSHANK, T.S., ARNOLD, J.G., HOTCHKISS, R.H. DEVELOPMENT OF A SNOWFALL-SNOWMELT ROUTINE FOR MOUNTAINOUS TERRAIN FOR THE SOIL WATER ASSESSMENT TOOL (SWAT). JOURNAL OF HYDROLOGY. 2002. v. 262. p. 209-223.

Interpretive Summary: The SWAT model is a hydrologic and water quality model that was originally developed for agricultural basins. The model was tested in the Upper Wind River basin in western Wyoming, a non-agricultural mountainous region with a large snowmelt component, representative of Rocky Mountain basins. The initial testing revealed that the model preformed poorly when simulating snowmelt and stream flow. In this study, several changes were made to the snowfall and snowmelt routines to improve model results. Modeling success was attained by adding algorithms in SWAT to simulate: 1) increased volume of precipitation observed at areas of moderate to high elevation, 2) variation in air and snow temperatures with elevation, 3) the areal ground coverage of snow, and 4) seasonal variations in snow pack melting. The modeling success obtained in the Upper Wind River basin shows that SWAT has the potential to be reliably applied to non-agricultural mountainous regions in the middle latitudes.

Technical Abstract: The soil water assessment tool (SWAT) is a hydrologic model originally developed to evaluate water resources in large agricultural basins. SWAT was not designed to model heterogeneous mountain basins typical of the western United States, and as a result, has performed poorly when applied to mountainous locations. The intent of this study was to increase the versatility of SWAT by developing the capability to simulate hydrology of a non-agricultural mountainous region with a large snowmelt component. A western Wyoming basin representative of Rocky Mountain basins, was selected to evaluate model performance, identify governing hydrologic processes, and improve the snowmelt routine. An initial evaluation of SWAT performance indicated an inability of the model to represent snowmelt processes. Based on simulation results and field observations, algorithms were developed which use elevation bands to distribute temperature and precipitation with elevation. Additional routines which control snowpack temperature, meltwater production, and areal snow coverage were designed to simulate the influence of season and elevation on the evolution of basin snowpack. The development of the new snowmelt algorithms improved the average annual Nash-Sutcliffe R**2 correlation between simulated and observed Wind River streamflow from an initial value of -0.70 to +0.86.