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ARS Home » Southeast Area » Fayetteville, Arkansas » Poultry Production and Product Safety Research » Research » Publications at this Location » Publication #157079
Title: QUANTIFICATION OF MODEL OUTPUT UNCERTAINTY DUE TO WATERSHED SIZE

Author
item GARG, VIJAY - UNIV OF ARKANSAS
item CHAUBEY, INDRAJEET - UNIV OF ARKANSAS
item HAGGARD, BRIAN

Submitted to: Transactions of the ASAE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/1/2003
Publication Date: N/A
Citation: N/A

Interpretive Summary: The objective of this study was to quantify the error in model predictions due to watershed size. Agricultural Non-point Source (AGNPS) model was used to quantify the model errors using measured data from watersheds of varying sizes from the Little Washita Basin in Oklahoma. AGNPS was calibrated in one watershed and then applied to the others; thus, the model was scaled up and down with watershed size. The study indicates that large uncertainty in the model outputs results with the change of watershed size.

Technical Abstract: A hydrologic/water quality model must be calibrated before used to predict watershed response. Often measured data from the watershed where the model intends to be applied may not be available. Under this condition, models are calibrated using data from different watersheds having similar land use, soil, and hydrologic conditions. However, if the watershed used for model calibration is not same as the watershed where the model is applied for hydrologic/water quality predictions, the difference in watershed characteristics may induce error in model output. The objective of this study was to quantify the error in model predictions due to watershed size. Agricultural Non-point Source (AGNPS) model was used to quantify the model errors using measured data from watersheds of varying sizes from the Little Washita Basin in Oklahoma. The study indicates that large uncertainty in the model outputs results with the change of watershed size.