Performance Evaluation of the HEC-HMS Model in Flood Discharge Simulation in the Upper Jeneberang Watershed

Abstract

The Jeneberang Watershed is one of the river basins in South Sulawesi Province that is highly vulnerable to flood disasters due to land use change and extreme rainfall. This study aims to analyze the rainfall-runoff transformation in the upper Jeneberang Watershed using the HEC-HMS hydrological model through calibration and validation processes. The data used include daily rainfall data from five rainfall stations and daily inflow discharge data from the Bili-Bili Dam for the period 2017–2022. The HEC-HMS model was constructed using the SCS Curve Number method for water loss estimation, the SCS Unit Hydrograph for transformation, the Recession Method for baseflow, and the Lag Method for flow routing. Calibration was conducted for four flood events (2017, 2018, 2020, 2021) and validation for two independent events (2019, 2022). Model performance was evaluated using NSE, R², PBIAS, and RSR parameters. Calibration results showed an average NSE=0.76, R²=0.84, PBIAS=−10.50%, and RSR=0.48, classified as Satisfactory to Very Good, while validation yielded NSE=0.63, R²=0.73, PBIAS=−2.48%, and RSR=0.60, with overall performance classified as Satisfactory to Good and PBIAS specifically classified as Very Good. The consistency between calibration and validation indicates the model possesses adequate generalization capability and is declared suitable and reliable for flood discharge simulation in the upper Jeneberang Watershed.