> 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/~/changes/GiVD5ID0WVyRIAumaMy2/introduction/channels/hyd-sed-lte.cha/wd_rto.md).

# sinu

Channel sinuosity

Channel sinuosity is a measure of how much a river or stream channel deviates from a straight line between two points. It is calculated by dividing the length of the channel by the straight-line distance between its endpoints. 

For rivers, the conventional classes of sinuosity are:

* sinu <1.05: almost straight
* 1.05 ≤ sinu <1.25: winding
* 1.25 ≤ sinu <1.50: twisty
* 1.50 ≤ sinu: meandering