Abstract: Range of sensitive parameter value associated with uncertainty should be performed in the calibration and validation process to establish more accurate watershed hydrological models. Evapotranspiration is one of the most dominant in a hydrological cycle other than surface runoff and subsurface processes. This research aims at an in-depth understanding of the SWAT-CUP ability on analyzing the impact of Potential Evapotranspiration (PET) methods on sensitive parameter and uncertainty streamflow simulations of the Kelantan river basin. The hydrological model was developed using the SWAT with three option of PET methods: Penman-Monteith (P-M), Priestley-Taylor (P-T) and Hargreaves (HG). The SWAT-CUP with SUFI-2 optimization algorithm and Nash-Sutcliffe as objective function were used to evaluate the model simulation compared to the streamflow discharge from years 1985-2000 for calibration and 2001-2016 for validation periods. The best value of NSE, R2 and PBIAS, indicated no significant difference and the model achieved very good performance during calibration and good performance during validation. The 95PPU plot and statistics value, p-factor yielded acceptable outcomes during calibration by bracketing of the observed streamflow data with 82, 74 and 75% for HG, P-T and P-M, respectively. However, the p-factor was achieved only 46, 40 and 44%, respectively during the validation period. The calibration strength of the r-factor was reached with HG (0.75, 0.67), P-T (0.92, 0.84) and P-M (0.88, 0.81) during calibration and validation. The uncertainty analysis showed that P-T is better performer during both the calibration and validation. Overall the SWAT Model was considered can give good performance with the built-in PET methods options.
Mohd Khardzir Husain, Gasim Hayder, Lariyah Mohd Sidek and Ali Najah Ahmed, 2020. Impact of Potential Evapotranspiration Method on Sensitivity and Uncertainty in Streamflow Analysis for Kelantan River Basin. Journal of Engineering and Applied Sciences, 15: 1228-1236.