도시 하천의 배수위 구간에서의 홍수 예·경보 강우량 기준 산정

Flood forecasting and warning systems have been mostly established in large rivers while they are lacking in most small-medium riv-ers. Thus, this study has constructed a flood forecasting and warning system for Danghyeon River basin, one of small-medium urbanrivers with backwater effects, which has difficulties in flood forecasting and warning. The developed flood forecasting and warningmodel coupled a rainfall-runoff analysis model, HEC-HMS with a water depth-flow analysis model, which can estimate flood fore-casting and warning rainfall thresholds at each rainfall duration time for flood water levels in junctions and warning alarm points totake into account backwater effects. Flood water levels at flood forecasting and warning alarm points in backwater lengths of the riverconsist of low water levels (initial overflow levels to the floodplain) and high water levels (design flood levels), and flood forecastingand warning rainfall thresholds were estimated as 60-min in 2-year for low water levels and 60-min in 70-year for high water levels. Itis expected that flood forecasting and warning thresholds with high reliability can be available by the calibration and verification onresults of this analysis in the future.