The physically-based, distributed flow and sediment transport modelling system SHETRAN was applied to the Draix basins to test its ability to represent badlands flow and erosion response, to quantify characteristic parameter values and to investigate spatial scale effects in badlands modelling. A unit gully, area 0.133 ha, was simulated using a 5-m grid resolution model and a single cell model, with comparable results. Application of the modes to a badlands basin, area 86 ha, suggests that transfer of parameter sets from the gully scale to a larger scale may be feasible but, given uncertainty in parameter evaluation, a separate calibration still yields improved results. Considering the flashy basin responses, satisfactory flow simulations were achieved using physically realistic parameter values, and sediment yields were well simulated within the bounds of uncertainty. Any scale effects which may distinguish the gully and basin simulations are masked by the uncertainty in parameter evaluation.