Curve Number Estimation for Ungauged Watershed in Semi-Arid Region

The Benanain Watershed is located in East Nusa Tenggara with an area of 3,181 km2 and divided into 29 sub-watersheds. itself eastern region Indonesia a unique climate condition called semi-arid. high rainfall intensity occurring short duration results large surface runoff erosion. Floods erosion semi-arid areas due to sensitive soils drought heavy extremely. This paper presents the application Soil Conservation Services-Curve Number (SCS-CN) real-flood flows through digital map soil type, land use, topography, heterogeneity physical condition, especially for ungauged watersheds. method used approach empirical estimate from relationship between rainfall, hydrology groups. watershed has that must analyze every sub-watershed. land-use secondary dryland forest by 44.26% hydrological group on B classification medium absorption potential 46.502% total area. curve number value ranges 56.54 73.90, where mean CN 65.32. (mm) sub-watersheds decreased about 74.65% when being or only 25.35% water becomes runoff. depth classified as standard response trend line (flat slope) equilibrium occurs 56.71 mm close 66.30. variability intense rainy season dry had significant influence Further analysis will be more accurate if it supported long data observation control. Doi: 10.28991/cej-2021-03091711 Full Text: PDF