Digital Elevation Models for topographic characterisation and flood flow modelling along low-gradient, terminal dryland rivers: A comparison of spaceborne datasets for the Río Colorado, Bolivia

•Spaceborne DEMs are evaluated for topographic characterisation and flood modelling.•DEMs are obtained for the low-gradient, Río Colorado terminal system, Bolivia.•TanDEM-X 12 m has the highest accuracy (RMSE 0.47 m).•DEM smoothing and upscaling effectively remove TanDEM-X 12 m data noise.•HEC-RAS 2D modelling reveals channel and overbank flooding patterns. Many dryland rivers are terminal systems, with small channels undergoing prominent downstream size reductions before ending on channelless floodplains, in wetlands, or at playa margins. Spaceborne Digital Elevation Models (DEMs) provide potential for assessing subtle topographic and hydrodynamic changes in these low-gradient, low-relief settings, but challenges are posed by limitations in vertical and horizontal accuracy. This study evaluates the use of different spaceborne DEMs for topographic characterisation and flood flow modelling of the low-gradient (