> 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/introduction-1/reservoirs/nutrients.res/untitled-5.md).

# mid\_n\_stl

A negative settling rate indicates that the reservoir sediments are a source of N. A positive settling rate indicates that the reservoir sediments are a sink for N.