> 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/basin-1/parameters.bsn/sw_init.md).

# sw\_init

All soils in the watershed will be initialized to the same fraction. If *sw\_init* = 0.0, the model will calculate it as a function of average annual precipitation. 

{% hint style="info" %}
We recommend using a warm-up period of at least 1 year, i.e. start the simulation at least 1 year prior to the period of interest. This allows the model to get the water cycling properly before any comparisons between measured and simulated data are made. If a warm-up period is incorporated, the value for *sw\_init* will not impact model results.
{% endhint %}


---

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