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. If you need help locating it, open the Run SWAT+ tab in the SWAT+ Editor to find its path. Once located, copy the executable file into the TxtInOut folder. If the executable is missing, the simulation will fail.

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"

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:

# Configure modified parameters
parameters = [
    {
        'name': 'esco',
        'change_type': 'absval',
        'value': 0.3
    },
    {
        'name': 'perco',
        'change_type': 'absval',
        'value': 0.6
    }
]

# Run SWAT+ simulation from the original `TxtInOut` folder
txtinout_reader.run_swat(
    sim_dir=r"C:\Users\Username\custom_folder",  # mandatory
    parameters=parameters,  # optional
    begin_date='01-Jan-2012',  # optional
    end_date= '31-Dec-2016',  # optional
    simulation_timestep=0,  # optional
    warmup=1,  # optional
    print_prt_control={'channel_sd': {'daily': False}},  # optional
    print_begin_date='15-Jun-2012',  # optional
    print_end_date='15-Jun-2016',  # optional
    print_interval=1  # optional
)