| Title: | Evaluation of different objective functions used in the SUFI-2 calibration process of SWAT-CUP on water balance analysis: A case study of the Pursat River basin, Cambodia |
| Authors: | Sao, D., T. Kato, L.H. Tu, P. Thouk, A. Fitriyah and C. Oeurng |
| Year: | 2020 |
| Journal: | Water |
| Volume (Issue): | 12(10) |
| Pages: | |
| Article ID: | 2901 |
| DOI: | 10.3390/w12102901 |
| URL (non-DOI journals): | |
| Model: | SWAT |
| Broad Application Category: | hydrologic only |
| Primary Application Category: | calibration, sensitivity, and/or uncertainty analysis |
| Secondary Application Category: | baseflow, interflow and/or other hydrologic component analysis |
| Watershed Description: | 5955 km^2 Pursat River, which drains to Tonle Sap Lake in Pursat Province in west central Cambodia. |
| Calibration Summary: | |
| Validation Summary: | |
| General Comments: | |
| Abstract: | Many calibration techniques have been developed for the Soil and Water Assessment Tool
(SWAT). Among them, the SWAT calibration and uncertainty program (SWAT-CUP) with sequential
uncertainty fitting 2 (SUFI-2) algorithm is widely used and several objective functions have been
implemented in its calibration process. In this study, eight different objective functions were used in a
calibration of stream flow of the Pursat River Basin of Cambodia, a tropical monsoon and forested
watershed, to examine their influences on the calibration results, parameter optimizations, and water
resources estimations. As results, many objective functions performed better than satisfactory in
calibrating the SWAT model. However, different objective functions defined different fitted values
and sensitivity rank of the calibrated parameters, except Nash–Sutcliffe efficiency (NSE) and ratio
of standard deviation of observations to root mean square error (RSR) which are equivalent and
produced quite identical simulation results including parameter sensitivity and fitted parameter values,
leading to the same water balance components and water yields estimations. As they generated
reasonable fitted parameter values, either NSE or RSR gave better estimation results of annual
average water yield and other water balance components such as annual average evapotranspiration,
groundwater flow, surface runoff, and lateral flow according to the characteristics of the river basin
and the results and data of previous studies. Moreover, either of them was also better in calibrating
base flow, falling limb, and overall the entire flow phases of the hydrograph in this area. |
| Language: | English |
| Keywords: | SWAT model; SUFI-2; objective functions; calibration; water balance components |