Assessment of Measurement Uncertainty by Incorporating IPEAT and SWAT

Abstract:

In the field of hydrologic and water quality modeling, measurement uncertainty is commonly specified to have potential impact over model predictions. However, few studies can be found to have measurement uncertainty considered in the calibration process due to the fact of lacking both available data and scientifically credible guidance. In this study, measurement uncertainty is jointly incorporated in the Integrated Parameter Estimation and Uncertainty Analysis Tool (IPEAT) with the Soil and Water Assessment Tool (SWAT) to evaluate model performance and the associated predictive uncertainty. Results show that streamflow simulations were not noticeably affected by the incorporation of measurement uncertainty. On the other hand, considerable impact was implied on sediment and ammonia predictions in terms of error statistics. In addition, no clear tendency of changes on predictive uncertainty while implementing varying levels of measurement uncertainty. The goal of this study was not to identify the superiority of model performance by including measurement uncertainty but to provide better understanding of the associated potential influences. Future studies and the corresponding work should consider measurement uncertainty as a substantial factor upon watershed modeling before conducting relevant decision making process.