The connections section contains all spatial object connectivity for the simulation run. In SWAT+ Editor, all connection object properties can be set through this section. For example, when you click on channels, you will see additional menu links appear for: properties, initialization, hydrology and sediment, and nutrients.

All connection objects have a similar format as seen in the above figure. The tabular view is shown by default. Click the map view tab to see a map with markers for the center coordinates of each object. Click an object marker in the map view, or edit icon on the left side of a row in the table to view or edit the object.

Each connection object will have a main properties object associated with it as well as a weather station. Click on these names in the table, or from the edit view page, click the button next to their names to view information about the properties object or weather station.

Each connection object may have outflow. This can be viewed in the table by clicking the eye icon in the rightmost column, or view from the edit page.

If you imported your project from GIS, your connection objects are populated automatically during project setup.

Explanation of SWAT+ Spatial Objects

Subbasin

The subbasin is defined by the DEM in the GIS interface as it always has been. All flow within the subbasin drains to the subbasin outlet.

Landscape Unit

A landscape unit (LSU) is defined as a collection of HRUs and can be defined as a subbasin, or it could be a flood plain or upland unit, or it could be a grid cell with multiple HRUs. The landscape unit is not routed, it only used for output. The landscape unit output files (waterbal, nutbal, losses, and plant weather) are output for HRUs, landscape units, and for the basin. Two input files are required: 1) landscape elements and, 2) landscape define. The elements file includes HRUs and their corresponding LSU fraction and basin fractions. The define file specifies which HRUs are contained in each LSU.

Routing Unit

A routing unit is a collection of hydrographs that can be routed to any spatial object. The routing unit can be configured as a subbasin, then total flow (surface, lateral and tile flow) from the routing unit can be sent to a channel and all recharge from the routing unit sent to an aquifer. This is analogous to the current approach in SWAT. However, SWAT+ gives us much more flexibility in configuring a routing unit. For example, in CEAP, we are routing each HRU (field) through a small channel (gully or grass waterway) before it reaches the main channel. In this case, the routing unit is a collection of flow from the small channels. We also envision simulating multiple representative hillslopes to define a routing unit. Also, we are setting up scenarios that define a routing unit using tile flow from multiple fields and sending that flow to a wetland.

The routing unit is the spatial unit SWAT+ that allows us to lump outputs and route the outputs to any other spatial object. It gives us considerably more flexibility than the old subbasin lumping approach in SWAT, and will continue to be a convenient way of spatial lumping until we can simulate individual fields or cells in each basin.

Click the paper icon in the leftmost blue toolbar to enter the editing section. Most editors in this section are a literal representation of the SWAT+ input files. The collapsible dark-gray headings on the left correspond to the section lines in the master watershed file (file.cio).

When you click on an editor section from the left menu, you'll find the default SWAT+ file name with which the section corresponds. This enables you to quickly look up further information in the SWAT+ input/output documentation.

Navigating the Editor

Most data is presented in a tabular format. When you click a row, you're presented with a form where you can make changes and save. The following features are common across many editor sections.

Action Bar

At the top of most tables, you'll see the following action bar. Not all sections will have each option available.

Click create new record to add an item to the table. Edit multiple records allows you to set a single value for one or more fields across all or selected rows in your table.

In the search box, start typing the name of the object you want to view. Matching options will appear below the text box. Click the one you want, then click the search icon button to the right.

The import/export data button allows you to quickly access your data in CSV (comma-separated values spreadsheet) format, in most cases. We recommend exporting your data (or empty table is okay) first to get a template with the column names. You may then modify the file and import it back into the editor.

Tables

Sort by a column in the table by clicking on the heading name. It will toggle ascending or descending direction as indicated by the arrows next to the name.

Tables with many records can be scrolled and then paged by clicking the page number or arrow links at the bottom of the table.

Each row may contain an edit/view icon on the far left to access the data in the row, and a delete icon on the far right (may need to scroll to access the far right of the table). We do not recommend deleting rows unless you are absolutely sure they are not used elsewhere in your model. Due to the relationships of data in SWAT+, deleting records could have unintended effects and break your model. Deleting cannot be undone; if in doubt, make a backup of your project SQLite database first.

Forms

Most objects in SWAT+ have a name field and are identified using this name. Names should be unique and not contain spaces (spaces will be automatically converted to underscores).

Each form will have a save changes button toward the bottom. Be sure to click this button after making any changes and before leaving the form.

Look-up Fields

There are a lot of relationships between objects in SWAT+. For example, all fields in your channel properties table link to rows in other tables. In SWAT+ Editor forms, you can easily select these related rows by starting to type an object's name and select it as it pops up. If you accidentally enter an incorrect name, the editor will return an error stating the record does not exist in your database.

Getting Started

We recommend starting in the climate section, and importing your weather generators and observed weather data. If you're coming from GIS, when you import weather generators or observed data, it will create weather stations and match them to your spatial objects automatically.

Weather Stations

Weather stations are linked from all of your connection objects (channels, HRUs, etc.) in SWAT+. If you are coming from QSWAT+, it is much better to import stations either from the weather generator section, or the observed weather file importer than it is to create them manually.

By importing through one of the methods described below, your new stations will be automatically matched your spatial connection objects.

Import Weather Generator Data

Click the import data button to import weather generator (wgn) data for your project. If you installed the SWAT+ databases, this file will be selected by default along with the CFSR world table. USA wgn data is also available from this database; type wgn_us to use this table.

You may also add your own data to this database using the wgn and corresponding wgn_mon tables.

Below the table name field is a check box asking if you are using observed weather data. By default (unchecked), when you click start import, weather stations will be created based on your wgn locations. If you are using observed weather data and prefer to have weather stations created based on this data, check this box--stations will not be created when you start import, and instead they will be created for you when you import your observed weather data files.

If you are not using observed weather data, it is important to leave the box unchecked so that weather stations are created for you.

CSV Import

If you do not want to use the SQLite database, you may import CSV files of your weather generator data. Two CSV files are required.

1. Stations CSV file:

   • Columns id, name, lat, lon, elev, rain_yrs

   • id should be uniquely numbered

Import Observed Weather Data

Import observed weather data from the top of the weather stations section. The data files may be in one of two formats: SWAT2012/Global Weather Data CFSR website format, or SWAT+.

SWAT2012/Global Weather Data CFSR Website Format

Each measurement included in your data must have the following entry file names:

Each entry file is a comma-separated list of stations. Each station name should have a corresponding .txt file (e.g., name p326-963 should have a p326-963.txt file).

Each station file should have the first line as the starting day as YYYYMMDD (e.g., 19790101). The following lines are the measurement for each day, one line per day. For temperature, each line will be max,min (e.g., 10.138,-2.662).

Weather data may be downloaded from the .

SWAT+ Format

Each measurement included in your data must have the following entry file names:

Each entry file has a title line (any text allowed), followed by a heading line, followed by a list of filenames for each station. Filenames should be listed alphabetically.

Each station file has a title line, followed by a heading line and data line for time and location. Measurements for each timestep are in the lines to follow. For temperature, the measurements will be listed as max then min.

Weather Generator Parameters

weather_wgn_cli

weather_wgn_cli_mon

Each entry in weather_wgn_cli will have 12 rows in weather_wgn_cli_mon.

Weather Stations Parameters

weather_sta_cli

When entering an observed weather file name in the station editor, you may start typing to search for existing weather files adding during the import step. If adding observed files manually, just type the name of the file (e.g., p326953.pcp), and put that file in the directory you plan to write input files (e.g., your TxtInOut). Files must be in SWAT+ format. If your weather data is in SWAT2012 format or from the Global Weather CFSR website, please use the import step to convert them to SWAT+.

weather_file

This table is only used if you import observed weather data files. If entering stations manually, this table will not be populated.

General watershed attributes are defined in the basin input files: codes and parameters. These attributes control a diversity of physical processes at the watershed level. The interfaces will automatically set these parameters to the default or recommended values listed in the variable documentation. Users can use the default values or change them to better reflect what is happening in a given watershed. Variables governing bacteria or pesticide transport need to be initialized only if these processes are being modeled in the watershed. Even if nutrients are not being studied in a watershed, some attention must be paid to these variables because nutrient cycling impacts plant growth which in turn affects the hydrologic cycle.

Codes

codes_bsn

Parameters

parameters_bsn

Time

Configure the number or years to run the simulation and time step. If you have observed weather data, make sure your simulation time falls within these dates.

time_sim

Configure the output files to print.

print_prt

print_prt_object

Each row in print_prt_object represents an output file that can be print daily, monthly, yearly, and average annual output for each.

Print Object Descriptions

Special note about using export coefficients with constant point source/inlet data

Recall objects are used for connecting point source or inlet data to your watershed. If you added point source in QSWAT+, when you import your project into SWAT+ Editor it will be connected via the recall section.

By default, constant data with all zero values during the default simulation period is added. To add your own recall data, click the recall item in the edit menu under connections. Click the item name under the rec column in the connection object table, or click the data item under recall in the edit menu on the left.

Constant Data

By default, your recall data is imported as constant. To insert your values, you can edit each item individually by clicking the edit button and manually entering each value. Alternatively, you may upload a CSV of your data.

From the recall data section, click the import/export button in the top right corner.

Export is selected by default. Choose a file name, and click the export CSV file button to get a template for your data.

Edit the CSV as needed, save, and then go back to the editor and click the import/output button again. This time toggle the import button. Choose your modified CSV file and click the import CSV data button. Your updated values will appear in the table.

Time Series Data

By default recall data is imported as constant, however this can be changed by clicking the edit button next to a row in the recall data table. Select the new time step for your data: daily, monthly, or yearly. Click the save changes button. Next, click the import/export button that appears on the form.

Export is selected by default. Choose a file name, and click the export CSV file button.

Open the file after it is exported to see the template for your data. Modify your data as needed matching the time step you selected previously. Be sure the years match your . In a yearly time step, t_step equals 1 through number of years. For monthly data, t_step equals the number of the month, and for daily it is the number of the day of the year.

To import your data, click the import/export data button again and this time click to toggle import. Choose your file and click import CSV file. Your new data will appear in the table.

Recall Table Definitions

Each record in recall_rec will have a data file named {name}.rec. All of this data is stored in a single recall_dat table in the database.

Decision tables are a precise yet compact way to model complex rule sets and their corresponding actions. Decision tables, like flowcharts and if-then-else and switch-case statements, associate conditions with actions to perform, but in many cases do so in a more elegant way (see Wikipedia article on decision tables).

Structure of decision tables:

1. Conditions

2. Condition alternatives

3. Actions

4. Action entries

Each decision corresponds to a variable, relation or predicate whose possible values are listed among the condition alternatives. Each action is a procedure or operation to perform, and the entries specify whether (or in what order) the action is to be performed for the set of condition alternatives the entry corresponds to. Many decision tables include in their condition alternatives the "don’t care" symbol, a hyphen. Using "don’t cares" can simplify decision tables, especially when a given condition has little influence on the actions to be performed. In some cases, entire conditions thought to be important initially are found to be irrelevant when none of the conditions influence which actions are performed.

Usage in SWAT+

There are four decision table sections in SWAT+: land use management, reservoir release, scenario land use, and flow conditions.

See the land use management documentation, under management schedules for how to choose a decision table for your HRUs.

Reservoir release decision tables are assigned from the reservoir properties section under connections in SWAT+ Editor.

Modifying Decision Tables in SWAT+ Editor

In the current version of SWAT+ editor, we do not have a GUI available for editing decision tables, however we have provided the ability to export the decision table file. You may then make changes to it in a text editor, and upload back into SWAT+ Editor.

Table Definitions

d_table_dtl

d_table_dtl_cond

d_table_dtl_cond_alt

d_table_dtl_act

d_table_dtl_act_out

Text File Example and Explanation

The following is an example of a decision table in the lum.dtl input file. It is a table for warm season annual crops, using continuous corn.

In the above table, there are 6 conditions, 4 alternatives and 3 actions.

Description of the conditions

1. soil_water – if soil water is too high (> 1.50*field capacity), it will be too wet to operate machinery

2. plant_gro – (“n”) Planting allowed if plant is not growing.

3. phu_base0 – (0.15) when the sum base zero heat units for the year (starting Jan 1) exceeds 0.15, indicating it’s warm enough to plant

Description of the alternatives

If all of the conditions for each alternative are met, outcomes are checked for ‘y’ to take action. Alternatives with dash (‘-‘) are not checked.

1. plant corn based on heat units: if soil water < 1.50*fc and if phubase0 > 0.15*phu_mat and if year_rot = 1 then check outcomes for ‘y’ and if ‘y’, take that action (plant)

2. Harvest corn based on crop accumulated heat units: if soil_water < 1.50*fc and if phu_plant > 1.15*phu_mat and if year_rot = 1 and then check outcomes for ‘y’ and if ‘y’, take that action (plant)

3. Harvest corn based on days since planting: if year_rot = 1 and if days_plant =200 then check outcomes for ‘y’ and if ‘y’, take that action (harvest)

Description of the actions

1. plant: corn – cross walked to plant name in plants.plt file

2. harvest_kill: corn – cross walked to plant name in plants.plt file grain – relates to harvest type in harv.ops file

3. rot_reset: rotation reset – for continuous corn (1 year rotation). The rotation year is reset to 1 at the end of every year.

A primary goal of environmental modeling is to assess the impact of human activities on a given system. Central to this assessment is the itemization of the land and water management practices taking place within the system. This section contains input data for planting, harvest, irrigation applications, nutrient applications, pesticide applications, and tillage operations. Information regarding tile drains and urban areas is also stored in this file.

In addition to the above, SWAT+ Editor groups the operations databases in this section of the editor. However, within the SWAT+ master watershed file (file.cio), these are listed under the ops section.

Land Use Management

This section is the entry point for management data in SWAT+. It comprises cross-walks to several other sections of data.

This data is accessed from the HRU properties section (hru-data.hru).

landuse_lum

Management Schedules

Management schedules comprise auto-schedules (decision tables) and/or operations schedules.

When you import your project from GIS, SWAT+ assigns auto-schedules for management based on your crop land use.

For example, oats is a cold annual crop. If this crop is in your HRUs, a decision table named pl_hv_oats will be created based on the template of pl_hv_wwht when you import your data from GIS.

Adding/Editing a Schedule

From the management schedules section, click create a new record or click edit on a row in the table. Give your schedule a unique name.

To add an automatic schedule, start typing a decision table name in the box provided. Click the desired result from the list of matches that pops up, and click the add button. If you enter more than one schedule, you can drag and drop to sort.

To add an operation, click the add operation button. Select your operation type from the form that pops up and complete the remaining fields. Click save when done to add the operation to your table.

When you're done adding automatic schedules and operations, click the save changes button to save your management schedule.

Table Parameters

management_sch

management_sch_auto

management_sch_op

Operations Types

Operation Data 1 Values

Operation Data 2 Values

Operations Databases

Values in the operations tables are provided in the SWAT+ datasets database and copied to your project database during project setup. You may modify them or add new rows as needed in the editor.

Harvest

Graze

Irrigation

Chemical Application

Fire

Sweep

Curve Number Table

Values in this table are provided in the SWAT+ datasets database and copied to your project database during project setup. You may modify them or add new rows as needed in the editor.

Conservation Practices

Values in this table are provided in the SWAT+ datasets database and copied to your project database during project setup. You may modify them or add new rows as needed in the editor.

Overland Flow Manning's n

Values in this table are provided in the SWAT+ datasets database and copied to your project database during project setup. You may modify them or add new rows as needed in the editor.