Progress and practical applications of flood forecasting systems in Taiwan

The flood forecasting systems operated in ten major rivers in Taiwan was discribed, including DRAINS, FEWS, SINO-TOPO, HEC-RAS and REFOR, of which each model had different rainfall-runoff and rivers hydraulic mechanisms. The practical applications of each forecasting system during typhoon periods were provided. The validation results indicate that all models are able to capture the main trend of the flood, especially in the vicinity of peak flow. The performance of all models on lag time and the relative error of all peak flow forecasting are within 3 hours and 17.7%, respectively. Overall, these models are capable of producing acceptable predictions and sufficient lead time that meet the requirement of operational hydrology, providing a reference for areas where the occurrence of typhoon is frequent and flood forecasting models are needed in practice.