Analysis of Rain – Flood Discharge Using HEC-HMS Model in Sadar Sub-catchment, Mojokerto

Increased rainfall in watershed is able to influence water level-discharges and cause flood events. Hydrology model carried out to describe the watershed response from rainfall and spatial data review through GIS used to identify flood hazard area as an early warning. Sadar sub-catchment located in Mojokerto Regency / City which has a high level of flood vulnerability, HEC-HMS model performance evaluation with statistics parameter result of Nash-Sutcliffe Efficiency (NSE) is 0.608 (satisfactory), Root Mean Squared Error (RMSE) - standard deviation ratio (RSR) is 0.603 (satisfactory) and Percent Bias (PBIAS) is 0.08 (very good). Six influence factors produce spatial map of flood hazard area in Sadar sub-catchment, these factors are flow accumulation, land slope, elevation, rainfall, soil type and land use.