> 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/basin-1/codes.bsn/headwater.md).

# gwflow

| Code | Option                   |
| ---- | ------------------------ |
| 0    | GWFlow module not active |
| 1    | GWFlow module active     |