> 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/connectivity/hru.con/frac.md).

# frac

{% hint style="warning" %}
When editing the fractions, the user has to make sure that they add up to 1. Otherwise, water will be added or removed from the system and the water balance will not close.
{% endhint %}