> For the complete documentation index, see [llms.txt](https://swatplus.gitbook.io/io-docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://swatplus.gitbook.io/io-docs/theoretical-documentation/section-4-erosion/sediment/musle/coarse-fragment-factor.md).

# Coarse Fragment Factor

The coarse fragment factor is calculated:

        $$CFRG=exp(-0.053\*rock)$$                                                             4:1.1.15

 where rock is the percent rock in the first soil layer (%).

Table 4:1-5: SWAT input variables that pertain to sediment yield.

| Variable Name | Definition                                                                                                   | Input File |
| ------------- | ------------------------------------------------------------------------------------------------------------ | ---------- |
| USLE\_K       | $$K\_{USLE}$$: USLE soil erodibility factor (0.013 metric ton m$$^2$$ hr/           (m$$^3$$-metric ton cm)) | .sol       |
| USLE\_C       | $$C\_{USLE,mn}$$: Minimum value for the cover and management factor for the land cover                       | crop.dat   |
| USLE\_P       | $$P\_{USLE}$$: USLE support practice factor                                                                  | .mgt       |
| SLSUBBSN      | $$L\_{hill}$$: Slope length (m)                                                                              | .hru       |
| HRU\_SLP      | $$slp$$: Average slope of the subbasin (% or m/m)                                                            | .hru       |
| ROCK          | $$rock$$: Percent rock in the first soil layer (%)                                                           | .sol       |