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United States Department of Agriculture

Agricultural Research Service

Research Project: DEVELOPMENT OF ALTERNATIVE PRACTICES FOR IMPROVED WATERSHED MANAGEMENT

Location: Cropping Systems and Water Quality Research

Title: Linking edge-of-field results to stream flow and water quality: a comparison between APEX and SWAT

Author
item Baffaut, Claire

Submitted to: Annual International SWAT Conference
Publication Type: Abstract Only
Publication Acceptance Date: February 15, 2011
Publication Date: June 15, 2011
Citation: Baffaut, C. 2011. Linking edge-of-field results to stream flow and water quality: a comparison between APEX and SWAT [abstract]. 2011 International SWAT Conference, Toledo, Spain, June 15-17, 2011. P. 24.

Technical Abstract: Methodologies to link edge-of-field observations to stream loadings need to be developed to integrate what we know of soil and water quality at the field scale to watersheds and river basins. A field scale model that is calibrated to observed flow, soil and water quality, and production data in a field provides a means to estimate the economic and environmental impacts of management practices under varying climate scenarios. A watershed scale model could extend the evaluation of these practices to the flow and water quality of streams, rivers and reservoirs. However, field scale models allow for increased definition of spatial variability and detailed simulation of the processes compared to watershed scale models. As the size of the area grows, there is a need for lumping spatial variations and simplifying algorithms. The APEX and SWAT models are particularly well adapted to this methodology because they belong to the same family of models and have many common input parameters. This study compares calibrated parameter sets and crop production and edge of field model results for a 35-ha field when simulated with APEX on one hand, using multiple sub-areas or one sub-area, and with SWAT on the other hand, as a 1 HRU watershed or as part of the larger 72 km2 watershed. Discussion on how critical processes are simulated in each model and what impact they have on the results will be included. The results will help identify the model effects and differentiate them from the true scale effects.

Last Modified: 8/1/2014
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