Morphometric analysis for understanding river basin hydrology: a case of gelda watershed, Tana Sub-Basin, Ethiopia

River basin hydrology is meaningfully influenced by morphometric characteristics such as shape, size, and relief. These features play a serious role in shaping hydrological processes, including runoff, infiltration, and erosion. This study examines the morphometric parameters of the Gelda watershed in the Tana sub-basin of Ethiopia to assess their impact on hydrology. The research utilized ASTER Digital Elevation Model (DEM) data with a resolution of 12.5 m and ArcGIS 10.5 for spatial analysis. Key morphometric parameters were extracted from the DEM, including stream order classifications, bifurcation ratio, and drainage density. Statistical methods were applied to evaluate the relationships between these parameters and various hydrological characteristics. The findings indicate that the Gelda watershed is classified as a 5th-order stream basin, with a mean bifurcation ratio of 1.76, suggesting moderate branching in the stream network. The drainage density was measured at 1.65 km/km², indicating a high potential for surface runoff and low permeability. This condition increases the basin's vulnerability to soil erosion and limits its water retention capacity. These situations are crucial for effective water resource management, soil conservation, and erosion control strategies in the region and other similar river basins worldwide. The study recommends implementing targeted soil conservation practices and effective water management strategies to mitigate erosion risks and enhance water retention. Future research should integrate morphometric analysis with hydrological modeling to better predict the impacts of land use changes on basin hydrology.