River discharge monitoring using remote-sensing and hydrological modeling: the case of Golina River, Danakil Basin, Ethiopia

Reliable discharge data remain scarce in arid and semi-arid basins, limiting water balance assessments and management. Although remote sensing indices and large-scale hydrological models have been applied, their suitability for small, data-scarce catchments such as the Golina River (Danakil Basin, Ethiopia) has not been systematically evaluated. This study directly compares the multiple pixel ratio (MPR) approach, which links Landsat 8 near-infrared reflectance to observed discharge with Global Flood Awareness System (GloFAS) reanalysis products. Using 251 Landsat scenes (2013-2024), we calibrated discharge estimates at different channel lengths and widths near the Addis-Alem station with in situ data (2022-2024). Results show that MPR, especially when applied close to the gauging station, outperforms GloFAS in capturing local discharge variability. This demonstrates a transferable satellite-based methodology for ungauged rivers, offering a robust alternative for monitoring discharge in data-scarce basins.