Hydrological Stream Flow Modelling for Calibration and Uncertainty Analysis Using SWAT Model in the Xedone River Basin, Lao PDR

The hydrological stream flow modeling is applied by the Soil for Water Assessment Tool (SWAT) model in the Xedone River basin, covering an area of 7,224.61 km2, in the southern part of Laos. The main objective of this research is to test the performance and feasibility of the SWAT model for predicting stream flow in the river basin. The model is calibrated and validated for two periods: 1993-2000 and 2001-2008, respectively, by using the SUFI-2 technique in this analysis. The SUFI-2 gives good results with the high value of R2 and NSE larger than 0.70 respectively, for daily simulation. Monthly simulation results during calibration and validation are also good with R2> 0.80 and NSE > 0.80. The sensitivity analysis results of the model to each sub-basin delineation and hydrological response unit (HRU) in this basin are 230 HRUs in the whole basin. For uncertainty results, the 95% prediction uncertainty (95PPU) brackets very well with the observed discharge. All of sources uncertainty results are captured by bracketing value, higher than 65% of the observed river discharge. All of the results in this study are important to water discharge. The calibrated model can be used for further analysis of the effects of the climate and land use change, water quality analysis and sediment yield analysis; furthermore, the modelling can be applied for planning dam construction in the future and flood disaster risk management and thereby is useful for the sustainable development of the country.