This paper presents a model for the description of sediment fluxes and deposition processes in a two-dimensional spatial context using the multiple-class Hairsine et al. sediment deposition equations. The model describes size-selective net deposition as a result of simultaneous deposition by settling and non-selective re-entrainment of previously deposited sediment. A critical comparison of field observations of net erosion and deposition in a watershed with complex topography with this physically based model is presented. The evaluation shows that the deposition model is capable of simulating reasonably both the observed size selectivity and spatial patterns of the deposition process. In this field study, the zone where a net deposit of sediment is re-entrained by overland flow was predicted to be quite limited spatially due to low sediment concentrations and the absence of aggregates in the eroded soil. Copyright © 2004 John Wiley & Sons, Ltd.