SWAT+ Simulation

pySWATPlus executes SWAT+ simulations using the TxtInOut folder generated during project creation with QSWAT+.

To run a SWAT+ simulation, the TxtInOut folder must include all required input files, which are created during simulation setup in the SWAT+ Editor via QSWAT+.

Additionally, the TxtInOut folder must contain the SWAT+ executable. The executable file compatible with your operating system and SWAT+ version can be obtained from the official GitHub releases.

Once the TxtInOut folder is properly configured with the necessary input files and the SWAT+ executable, you can initialize the TxtinoutReader class to interact with the SWAT+ model:

import pySWATPlus

# Replace this with the path to your project's TxtInOut folder
txtinout_dir = r"C:\Users\Username\project\Scenarios\Default\TxtInOut"

# Initialize TxtinoutReader class
txtinout_reader = pySWATPlus.TxtinoutReader(
    tio_dir=txtinout_dir
)

pySWATPlus offers multiple options for executing SWAT+ simulations, providing flexibility for diverse workflows and automation needs.

The following sections demonstrate different approaches, including modifying input parameters, running a single simulation, and performing batch processing.

Trial Simulation

This simple example runs a SWAT+ simulation without changing any input parameters, ensuring that the setup works correctly:

txtinout_reader.run_swat()

Simulation in a Custom Directory

To keep your original TxtInOut folder unchanged, it is recommended to run SWAT+ simulations in a separate empty directory. This allows you to perform experiments without affecting your main project. The following steps demonstrate how to perform a simulation in a custom directory:

Copy required files to the custom directory:

# Replace this with your desired empty custom directory
sim_dir = r"C:\Users\Username\custom_folder" 

# Ensure the required files are copied to the custom directory
txtinout_reader.copy_required_files(
    sim_dir=sim_dir
)

Initialize TxtinoutReader class for the custom directory

sim_reader = pySWATPlus.TxtinoutReader(
    tio_dir=sim_dir
)

Run simulation
```
sim_reader.run_swat()
```

Step-wise Configurations and Simulations

The following steps demonstrate how to configure parameters in a custom directory and run a simulation step by step:

Modify simulation timeline:

# Update timeline in `time.sim` file
sim_reader.set_simulation_period(
    begin_date='01-Jan-2012',
    end_date='31-Dec-2016'
)

Set warm-up years:

# Set warm-up years in `print.prt` file
sim_reader.set_warmup_year(
    warmup=1
)

Enable required simulation files:

# Ensure simulation outputs for `channel_sd` object in `print.prt` file  
sim_reader.enable_object_in_print_prt(
    obj='channel_sd',
    daily=False,
    monthly=True,
    yearly=True,
    avann=True,
)

Set print interval within the simulation period:

# Set print interval in `print.prt` file
sim_reader.set_print_interval(
    interval=1
)

Set print period within the simulation timeline to record result in output files:

# Set print period in `print.prt` file  
sim_reader.set_print_period(
    begin_date='15-Jun-2012',
    end_date='15-Jun-2016'
)

Run the SWAT+ simulation with a modified esco parameter:

parameters = [
    {
        'name': 'esco',
        'change_type': 'absval',
        'value': 0.5
    }
]
sim_reader.run_swat(
    parameters=parameters
)

Configurable Simulations in a Single Function

Instead of performing each step separately as explained above, you can run a SWAT+ simulation in a separate empty directory by configuring all options at once using a single function:

# Run SWAT+ simulation to a custom directory
txtinout_reader.run_swat(
    sim_dir=r"C:\Users\Username\empty_folder",  # directory (optional)
    parameters=[
        {
            'name': 'esco',
            'change_type': 'absval',
            'value': 0.3
        },
        {
            'name': 'perco',
            'change_type': 'absval',
            'value': 0.6
        }
    ],  # modified parameter value (optional)
    begin_date='01-Jan-2012',  # simulation begin date (optional)
    end_date= '31-Dec-2016',  # simulation end date (optional)
    simulation_timestep=0,  # simulation time step (optional)
    warmup=1,  # warm-up years (optional)
    print_prt_control={
        'channel_sd': {'daily': False}
    },  # control print.prt file (optional)
    print_begin_date='15-Jun-2012',  # begin date to print output (optional)
    print_end_date='15-Jun-2016',  # end date to print output (optional)
    print_interval=1  # interval to print output (optional)
)