Watershed erosion modeling using the probability of sediment connectivity in a gently rolling system

•We develop a new sediment connectivity model that relies on intersecting probability theory.•Our new probability model is integrated within a watershed erosion model framework.•Only 13.5% of the lowland watershed shows sediment connectivity on the wettest day.•Disconnectivity dominates microtopography, gullies, karst sinkholes and floodplains.