Modelling the streamflow of a river basin using enhanced hydro-meteorological data in Malaysia

Paddy rice is an important food crop in Malaysia providing food for the nation and yet its water demand is relatively high compared with the other crops. Increasing the problem are concerns about uncertainties in crop water demands, rainfall patterns and stream flows owing to climate change effects. Thus, predicting flows while accounting for climate change is critical in future. However, due to poor meteorological records in many catchments, a previous study presented a new meteorological data set gridded from daily observation data countrywide. In this study, the stream flow simulation for the Bernam River Basin was assessed using this data set as inputs to the soil and water assessment tool (SWAT) model. Flow calibration was done for 17 years and validation was performed for 8 years. The results showed that simulated values matched well with enhanced data values with (R²), NSE and PBIAS being 0.67, 0.62 and -9.4 for the calibration period and 0.62, 0.61 and -4.2 for the validation period. The study shows that the new data is applicable in the Bernam watershed, and that the SWAT model was able to predict flows reasonably well with these data, thus can be used to study future impacts on stream flow of this river.