Sensitivity Analysis of Rainfall-Runoff Model in Malino Sub-Watershed

Abstract

Overtime, science has been developing and trying to use modelling system in the management of hydrology. In this paper, we present a sensitivity analysis for the HEC-HMS rainfall-runoff model. Sensitivity analysis is used to determine the parameter which most influences the result of the model. The main objective of this research is to investigate the sensitivity of parameter in model and to analyze the influence of the graph types used for unit hydrograph. In addition, we also compare the result of lumped and semi-distributed models based on stream order to analyse a common watershed issue. This study will make a model of rainfall-runoff using a sub-catchment distribution method based on stream order. ArcGIS and HEC-HMS were used as softwares to process data. The data needed in this study come from secondary data sourced from various sources. The data that will be processed first is DEM (Digital Elevation Model). DEM used in this study was sourced from the Geospatial Information Agency or commonly referred to as DEMNAS (The National DEM). ArcGIS will process geospatial data in the form of DEM which data results can be used directly to make model in HEC-HMS. Then, the results of the rainfall-runoff model will be calibrated using observed unit hydrograph. From the result of sensitivity analysis, it was concluded that impervious is the most sensitive parameter. Moreover, this paper also can be used as guidelines for use in rainfall-runoff modelling on HEC-HMS.