# Soil erosion model input

The soil erosion model input can be found in the SEDIMENT module part of the config file and the subsequent 6 modules related to the different soil erosion models included in SPHY. The first step is to select a soil erosion model, which include: MUSLE (1), MMF (2), INCA (3), SHETRAN (4), DHSVM (5) and HSPF (6).

The rock fraction map is used by MUSLE, MMF and SHETRAN, and can be ignored for the other 3 soil erosion models. The rock fraction map should be provided in the range between 0-1. Rock fraction values can be obtained by the empirical formulations by (Poesen, 1998), which determine rock fraction based on slope gradient.

The soil erosion models use the accumulated runoff to determine the detachment by runoff. This can lead to unrealistic soil erosion estimates in large study areas (>10 km2), where water accumulates into channels and rivers. To prevent this from happening, the model can ignore the detachment by runoff in the channels and rivers with a predefined upstream area (km2). To use this feature, the exclChannelsFLAG should be set to 1.

For all soil erosion models, the user needs to provide a table with land use specific model parameters, such as ground cover and plant height. These tables are linked with the land use map provided under LANDUSE.

In the following subsections the model specific parameters are discussed.
