Morphometry Analysis of Sedayu Mountainous Catchment Areas from Detailed Aerial Photos

Abstract Morphometric analysis is a powerful tool to understand the hydrological process quantitatively and main requirement determine characteristics of watershed. drainage Sedayu River Sub-watershed, Semaka District, Tanggamus Regency, Lampung Province was carried out using Digital Elevation Model (DEM) data. The primary data used aerial photography drones, location photos representing watersheds concern. catchment area morphometrics were obtained from extraction morphometric combined DEM mountain watershed topographic maps by ArcGIS software. Based on reports over period time, at several points in there are frequent river floods that overflow during heavy rains. flood-prone areas with high rainfall needed. morphology has contrasting variations consisting gentle alluvial plains, some which Bukit Barisan hills varying slope variations. this study divided into 3 sub-watersheds, namely: sub-watershed A, B, C. However, only A focus because its longest river, record flood disasters, landslide records, upstream residential. parameters such as ( ), length Lb L n width W density D d bifurcation ratio R b circularity c ). results calculations 4.82 km, Sub-watershed 8.996 0.686 4.861 km 2 these can be calculated ) 2.719 km/km means rough type inundated surface, permeable sub-soil, resistant erosion. Bifurcation 3.333 rapid rise fall floodwater. Then, Ratio 0.32 elongated so peak discharge decrease flow quickly causes link response rainfall-runoff. characteristic right reference for planning strategies soil erosion control conservation.