> 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/swat+-output-files/hydrographs.md).

# Hydrographs

SWAT+ prints two hydrograph output files per time step, one for incoming and one for outgoing hydrographs. The printing of hydrographs is controlled by entering "y" or "n" in the *hyd* line in [print.prt](/io-docs/introduction-1/simulation-settings/print.prt.md). Hydrographs can be printed at daily, monthly, yearly, and average annual time steps. The names of the hydrograph output files are as follows: 

* hydin\_day.txt
* hydout\_day.txt
* hydin\_mon.txt
* hydout\_mon.txt
* hydin\_yr.txt
* hydout\_yr.txt
* hydin\_aa.txt
* hydout\_aa.txt

The number of lines in the hydrograph output files depends on the number of connections between spatial objects defined in the SWAT+ setup. In the incoming hydrograph files, for each receiving object there will be one line  per source object it receives a hydrograph from. The number of lines per source object in the outgoing hydrograph files equals the number of receiving objects it sends hydrographs to. 

{% tabs %}
{% tab title="In" %}

| Field        | Description                                     | Unit |
| ------------ | ----------------------------------------------- | ---- |
| jday         | Julian Day                                      | n/a  |
| mon          | Month                                           | n/a  |
| day          | Day of the month                                | n/a  |
| yr           | Year                                            | n/a  |
| name         | Name of the receiving object                    | n/a  |
| type         | Type of the receiving object                    |      |
| objtyp       | Type of the source object                       |      |
| typ\_no      | ID of the source object                         |      |
| hyd\_typ     | Type of the incoming hydrograph                 |      |
| fraction     | Fraction of the incoming hydrograph             |      |
| flo          | Incoming flow                                   | m3/s |
| sed          | Incoming sediment                               | tons |
| orgn         | Incoming organic nitrogen                       | kg   |
| sedp         | Incoming sediment phosphorus                    | kg   |
| no3          | Incoming nitrate nitrogen                       | kg   |
| solp         | Incoming soluble phosphorus                     | kg   |
| chla         | Incoming Chlorophyll-a                          | kg   |
| nh3          | Incoming ammonia nitrogen                       | kg   |
| no2          | Incoming nitrite nitrogen                       | kg   |
| cbod         | Incoming carbonaceous biochemical oxygen demand | kg   |
| dox          | Incoming dissolved oxygen                       | kg   |
| san          | Incoming sand                                   | tons |
| sil          | Incoming silt                                   | tons |
| cla          | Incoming clay                                   | tons |
| sag          | Incoming small aggregates                       | tons |
| lag          | Incoming large aggregates                       | tons |
| grv          | Incoming gravel                                 | tons |
| null         |                                                 |      |
| {% endtab %} |                                                 |      |

{% tab title="Out" %}

| Field         | Description                                     | Unit |
| ------------- | ----------------------------------------------- | ---- |
| jday          | Julian Day                                      | n/a  |
| mon           | Month                                           | n/a  |
| day           | Day of the month                                | n/a  |
| yr            | Year                                            | n/a  |
| name          | Name of the source object                       | n/a  |
| type          | Type of the source object                       |      |
| objtyp        | Type of the receiving object                    |      |
| typ\_no       | ID of the receiving object                      |      |
| hyd\_typ      | Type of the outgoing hydrograph                 |      |
| fraction      | Fraction of the outgoing hydrograph             |      |
| flo           | Outgoing flow                                   | m3/s |
| sed           | Outgoing sediment                               | tons |
| orgn          | Outgoing organic nitrogen                       | kg   |
| sedp          | Outgoing sediment phosphorus                    | kg   |
| no3           | Outgoing nitrate nitrogen                       | kg   |
| solp          | Outgoing soluble phosphorus                     | kg   |
| chla          | Outgoing Chlorophyll-a                          | kg   |
| nh3           | Outgoing ammonia nitrogen                       | kg   |
| no2           | Outgoing nitrite nitrogen                       | kg   |
| cbod          | Outgoing carbonaceous biochemical oxygen demand | kg   |
| dox           | Outgoing dissolved oxygen                       | kg   |
| san           | Outgoing sand                                   | tons |
| sil           | Outgoing silt                                   | tons |
| cla           | Outgoing clay                                   | tons |
| sag           | Outgoing small aggregates                       | tons |
| lag           | Outgoing large aggregates                       | tons |
| grv           | Outgoing gravel                                 | tons |
| null          |                                                 |      |
| {% endtab %}  |                                                 |      |
| {% endtabs %} |                                                 |      |