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ARS Home » Southeast Area » Fayetteville, Arkansas » Poultry Production and Product Safety Research » Research » Publications at this Location » Publication #171970
Title: COMPARISON OF TWO METHODS FOR MODELING MONTHLY TP YIELD FROM A WATERSHED

Author
item WHITE, KATI - UNIVERSITY OF ARKANSAS
item CHAUBEY, INDRAJEET - UNIVERSITY OF ARKANSAS
item Haggard, Brian
item MATLOCK, MARTY - UNIVERSITY OF ARKANSAS

Submitted to: Proceedings of American Society of Agricultural Engineers
Publication Type: Proceedings
Publication Acceptance Date: 5/1/2004
Publication Date: 8/1/2004
Citation: White, K.L., Chaubey, I., Haggard, B.E., Matlock, M.D. 2004. Comparison of two methods for modeling monthly tp yield from a watershed. In: Proceedings of American Society of Agricultural Engineers, August 1-4, 2004, Ottawa, Ontario, Canada. 2004 CDROM.

Interpretive Summary:

Technical Abstract: Watershed models seldom contain detailed components that simulate instream nutrient processes. However, the Soil and Water Assessment Tool (SWAT) watershed model has incorporated some instream modeling capabilities. The goal of this project was to compare total phosphorus (TP) predictions from a watershed model with incorporated instream components to a watershed model linked with a stand alone instream water quality model for War Eagle Creek Watershed in Northwest Arkansas. Our objectives were to: 1) predict monthly TP yields using the SWAT model with instream components active for a watershed (method 1), 2) predict monthly TP yields using a SWAT model without instream components active linked to a QUAL2E model (method 2), and 3) determine if significant differences exist between the two modeling methods. Regression analysis of the two modeling methods provided R**2 values of 0.579 and 0.339, respectively. In addition, two variations of the Pearson product-moment correlation (alpha = 0.05) were evaluated. Statistical results indicated that correlation coefficients and regression slopes for the two data sets were not significantly different. This implies that no additional knowledge was gained concerning monthly TP yields from the watershed by adding the detailed instream, QUAL2E model to the SWAT model. Therefore, the SWAT model with active instream components (method 1) sufficiently predicts TP yields from War Eagle Creek Watershed. Although War Eagle Creek Watershed is not greatly urbanized (only 0.5% by area), point and nonpoint P sources are present and included in the modeling process. Hence, monthly TP yields from watersheds with similar characteristics can be estimated using the SWAT model (method 1).