# cn3\_swf

This parameter gives the user control over the level of saturation of the soil that has to be reached before the model switches from using the Curve Number for moisture condition II to moisture condition III. Thus, it can be used to delay the onset of surface runoff after dry periods.

<figure><img src="/files/nxVkxRfoVk1Fnc1xGfVv" alt="" width="375"><figcaption><p>The effect of cn3_swf on the Curve Number</p></figcaption></figure>


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://swatplus.gitbook.io/io-docs/introduction-1/hydrology/hydrology.hyd/cn3_swf.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.