Models of fluvial erosion have a long history in landform evolution modeling. Interactions between rivers and processes acting at hillslopes (e.g., landslides) are receiving growing interest in this context. While present-day computer capacities allow for applying such coupled models, there is still a scaling problem when considering rivers to be linear elements on a topography. Based on a reinterpretation of old empirical results, this study presents a new approach to overcome this problem.