A Unifying Transfer Model for Soil Erosion, River Bedload and Chemical Transport

Transfers of material by a water flow are simulated using different models, owing for the various processes involved. This gave rise to the development of numerous models (and associated computer codes). This diversity may be apparent only: because models are being used in different fields of hydrology and because they are written in different ways, they look different but could, indeed, be identical. A set of equations, termed transfer equations, is proposed to model various transfers of materials between the soil and surface water through an exchange layer. Its implementation in the open-source software FullSWOF 1D is verified against the approximation of an exact solution, assuring its proper functioning. Subsequent results show that the transfer equations can represent independently-published models in scientific issues as different as soil erosion , river bedload, and chemical transport. Hence, the transfer equations are a unifying transfer model, allowing various processes to be represented by a single model and to simulate the fate of both particles and chemicals using a single computer code. The use of the unifying transfer equations will decrease the number of models to be used, and will help to limit the number of computer codes to be developed. They will also help in drawing parallels between different fields of hydrology.