This study aims to estimate peak river discharges using IMERG satellite-based precipitation data via Google Earth Engine (GEE) combined with hydrological modeling in HEC-HMS, focusing on two case studies: the Blanco River Basin in Ecuador and the Yeon...
This study aims to estimate peak river discharges using IMERG satellite-based precipitation data via Google Earth Engine (GEE) combined with hydrological modeling in HEC-HMS, focusing on two case studies: the Blanco River Basin in Ecuador and the Yeongsan River Basin in Korea. High-resolution remote sensing products were integrated with a physically based hydrological model to assess extreme flood flows in data-scarce tropical and temperate, monsoonal catchments. Digital Elevation Models from USGS SRTM 1 Arc-Second Global data were processed to delineate subbasins and extract drainage networks, while virtual rainfall stations were established within each subbasin to ensure consistent precipitation inputs. The selected extreme rainfall events, a 10-day flood in Blanco River on March 18, 2023, and the July 17-18, 2025, flood in Yeongsan, were simulated to estimate peak discharges. The Blanco River Basin reached a peak discharge of approximately 12,814.3 m³/s at the basin outlet, while the Yeongsan River Basin reached approximately 4,170.1 m³/s. These results demonstrate that satellite-derived precipitation, when properly preprocessed and incorporated into HEC-HMS, can provide reliable estimates of extreme flows in basins with limited ground data. The study underscores the potential of GEE-based IMERG data for flood risk assessment, infrastructure planning, and early-warning systems in regions prone to rapid-onset flooding. Keywords: Peak discharge analysis, Extreme rainfall events, Hydrological modeling, Satellite precipitation