Catchment Calibration Using Fractional-Factorial and Central-Composite-Designs-Based Response Surface

Abstract

A new catchment calibration approach based on the fractional-factorial and central-composite designs (FFD-CCD) is presented in this paper. The proposed method requires fewer simulations (almost 75% less) than the approach based on the factorial and central-composite designs (FD-CCD) (Ibrahim and Liong 1992). However, the reduction in the number of simulations does not significantly affect the prediction accuracy of the model. The calibration model has been applied to the Upper Bukit Timah catchment in Singapore. Results show that the prediction errors in peak flow and runoff volume in the proposed model are as small as those errors resulting from the original FD-CCD approach.