The researchers used a mix of grid data and Illudas model to analyze how rainfall causes flooding along the Bulgang river in an urban area. By estimating runoff with GIS data and using network analysis, they predicted how much water would flow at Jeungsan bridge. Comparing their estimates to real data, they found that the model was pretty close – about 11.70% to 16.30% off in total volume, and 1.10% to 6.96% off in peak flow. For most storms, their predictions were off by less than an hour in when the peak flow would happen. Overall, this approach seems promising for forecasting flood risk in urban areas and could help prevent disasters.