  The Morgan-Morgan-Finney (MMF) model is a widely used semi-physically based
soil erosion model that has been tested and validated in various land use types
and climatic regions. The latest version of the model, the modified MMF (MMMF)
model, improved its conceptual physical representations through several
modifications of the original model. However, the MMMF model has three
problematic parts to be corrected: 1) the effective rainfall equation, 2) the
interflow equation, and 3) the improperly normalized C-factor of the transport
capacity equation. In this commentary, we identify and correct the problematic
parts of the MMMF model, which should result in more accurate estimations of
runoff and soil erosion rates.
