Design Rainfall Analysis and SCS Synthetic Unit Hydrograph-Based Flood Discharge Estimation in the Karangnongko Dam, Bojonegoro

This study estimated design rainfall and flood hydrographs for the Karangnongko Dam Watershed, Bojonegoro, using the Soil Conservation Service Synthetic Unit Hydrograph (SCS-SUH) method. The analysis combined isohyetal rainfall estimation, frequency analysis and goodness-of-fit testing, Mononobe temporal distribution, and the Alternating Block Method. We converted effective rainfall into hydrographs to estimate peak discharge, time to peak, and runoff volume across rainfall return periods. Longer return periods produced higher design rainfall, peak discharges, and runoff volumes, while hydrograph shapes remained relatively consistent under unchanged watershed characteristics. The approach provides rainfall-based design flood estimates that can inform hydraulic structure planning, reservoir operation, and flood mitigation in data-limited watersheds Contribution to Sustainable Development Goals (SDGs):SDG 6: Clean Water and SanitationSDG 9: Industry, Innovation and InfrastructureSDG 11: Sustainable Cities and Communities