The researchers developed a flood forecasting and warning system for a small-medium urban river called Danghyeon River. They combined a rainfall-runoff analysis model with a water depth-flow analysis model to estimate rainfall thresholds for flood forecasting and warning. The system considers backwater effects, which can cause water levels to rise in certain areas. The study found that for low water levels, a 60-minute rainfall in a 2-year period is needed, while for high water levels, a 60-minute rainfall in a 70-year period is required. This system aims to provide reliable flood forecasting and warning thresholds for the future.