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ARS Home » Midwest Area » Columbia, Missouri » Cropping Systems and Water Quality Research » Research » Publications at this Location » Publication #321268

Title: Is site-specific APEX calibration necessary for field scale BMP assessment?

item SENAVIRATNE, ANOMAA - University Of Missouri
item Baffaut, Claire
item LORY, JOHN - University Of Missouri
item UDAWATTA, RANJITH - University Of Missouri

Submitted to: Annual International SWAT Conference
Publication Type: Abstract Only
Publication Acceptance Date: 9/11/2015
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: The possibility of extending parameter sets obtained at one site to sites with similar characteristics is appealing. This study was undertaken to test model performance and compare the effectiveness of best management practices (BMPs) using three parameters sets obtained from three watersheds when applied to a fourth one. The first watershed was a no-till corn-soybean field in northeast Missouri, during 1993-1997 (parameterization 1). The second one was the same watershed during 1998-2008 after the establishment of agro-forestry buffers (parameterization 2). The third watershed was a corn-soybean field, 90-km from the Novelty site and with the same claypan soils (parameterization 3). An adjoining field with terraces, a grass waterway, and winter cover-crops, and monitored during 2011-2013 was used as the validation watershed. Model performance for runoff was good with all three parameterizations; coefficient of variation (r2): 0.7 to 0.8, Nash-Sutcliffe Coefficient (NSC): 0.3 to 0.6, and percent bias (Pbias): -20 to 6%. Model performance for sediment was good only with parameterizations 1 and 3 (r2: ~0. 5, NSC: 0.4 to 0.5 and Pbias: 23 to 53%). For total phosphorus (TP), model performance was good only with parameterization 3 (r2: 0.9, NSC: 0.5 and Pbias: 66 %). Thirty-year average annual predictions varied between the three parameterizations by 1-51%. However, the relative reductions in runoff, sediment and TP remained within 12%. All parameterizations predicted terraces were the most effective for sediment and TP, and cover crops for runoff. All three parametrizations showed good robustness in quantifying the relative effectiveness of BMPs.