Analysis of Flood Discharge of Wae Mese Watershed, in Labuan Bajo using the Snyder Hydrograph Sinthetic and Soil Conservation Service Curve Number Unit Hydrograph

The Wae Mese River is one of the major rivers in the Labuan Bajo area, West Manggarai Regency, and plays an important role in supporting local community activities and the regional hydrological system. Historical flood records indicate that the region experienced extreme rainfall events on March 7, 2019, and December 31, 2021, which caused inundation in several villages within the Wae Mese Watershed (DAS) and resulted in significant material losses. These events highlight the need for a more accurate hydrological analysis to better understand the watershed’s response to extreme rainfall and to support future flood mitigation efforts This study aims to analyze flood discharge in the Wae Mese River using the Soil Conservation Service Curve Number (SCS-CN) method to estimate effective rainfall based on land use, soil type, and hydrologic soil group characteristics. The estimated effective rainfall was then transformed into a flood hydrograph using the SCS Unit Hydrograph approach, and the rainfall–runoff processes were simulated using the Hydrologic Engineering Center–Hydrologic Modeling System (HEC-HMS). The findings provide important insight into the hydrological response of the Wae Mese Watershed to extreme rainfall events and are expected to serve as a valuable reference for flood control planning, watershed management, and hydrometeorological disaster mitigation in the study area.