Sediment transportation in river network plays a pivotal role in linking land use and land cover, topography, and geology in headwater catchments to biogeochemistry in large rivers and reservoirs, and cascading to the ocean. However, most existing earth system models lack representations of sediment transportation in rivers. To fill this gap, a physically-based large-scale sediment transportation module is being developed within the framework of Model for Scale Adaptive River Transport (MOSART) used in earth system models. This new module consists of three major components: 1) a soil erosion process representation; 2) a riverine transport and transform process representation; and 3) a simple parameterization of reservoir trapping effect on sediment. The simulated sediment will be evaluated against sediment observations at the global scale. The model will be used to explore the effects of reservoir regulation on the global sediment budget and the inter- and intra-annual variations of sediment fluxes.