Sensitive Analysis of WRF-Hydro’s Parameters for Multi-Peak Flood Flow: A Case Study in the Ve River Basin, Vietnam

Abstract The distributed hydrological model is considered one of the important supporting tools for flood forecasting and warning at different sizes of river basins. However, determining an optimal parameter set for these models has been facing with challenges, especially for multi-peak flood flow. Therefore, the primary objective of this study is to explore the sensitivity parameter set of the WRF-Hydro model for a three-peak flood in the Ve River basin, Vietnam. The considered parameters in the paper are the runoff infiltration parameter (REFKDT), the soil saturated hydraulic conductivity (DKSAT), the saturated volumetric soil moisture content (SMCMAX), the surface retention depth (RETDEPRTFAC), the overland flow roughness scaling parameter (OVROUGHRTFAC) and the channel Manning roughness parameter (MannN). The findings indicate that the simulated streamflow is less responsive to changes in the OVROUGHRTFAC and RETDEPRTFAC parameters and more sensitive to changes in the SMCMAX, REFKDT, DKSAT, and MannN parameters. Under unsaturated soil moisture conditions, the simulated streamflow tends to decrease as the values of REFKDT and DKSAT increase. Conversely, the simulated streamflow increases as the values of REFKDT and DKSAT rise with saturated soil conditions.