Sensitivity analysis of arc-hydro on the watershed responses in urban and rural area

Program for predicting runoff discharge from rain events is HEC-HMS. The results of the HEC-HMS hydrograph depends on the characteristics of the watershed. Arc-Hydro/HEC-Geo HMS are programs that are usually used in hydrological modelling. The results of the Arc-Hydro analysis depends on the sensitivity of the topographic map. Due to complex surface shapes because the effect of high-level urbanization in urban areas, it will cause error in extracting the pattern of the natural network path due to roads and buildings. This will complicate the Arc-Hydro program in determining watershed boundaries. The objective of this research is to analyse the sensitivity of Arc-Hydro to make watershed delineation and their influence on the watershed responses using HEC Geo-HMS. Based on the result of this study, the resulting catchment area of the Arc-Hydro delineation with manual (based on the field survey) delineation has a significant difference in urban area compared to rural area. These results also have a significant impact on the results of hydrograph simulations of flood runoff in urban areas. So it was concluded that the determination of watershed boundaries in urban areas does not only rely on the Arc-Hydro but also needs to be validated based on the field survey.