SWAT+ HRU Processor

GUI and command-line helper for making smaller SWAT+ TxtInOut runs from selected HRU IDs. The original TxtInOut folder is used as the source; the tool creates a copied working folder and rewrites files inside that copy.

What It Creates

For one HRU, the output folder is created inside the selected source directory as:

solo_<hru_id>

For more than one HRU, the output folder is:

multi_<YYYYMMDD_HHMMSS>

If a matching solo_<hru_id> folder already exists, it is replaced. The copy skips common generated output files such as *.out, *.fin, *.sqlite, *.db, *.log, *.pid, fort.*, *.txt, and *.csv.

Modes

Isolated HRU Mode

This is the default mode when Keep Routing is off.

The tool keeps only the selected HRU rows and removes routing from those HRUs. This is useful when you want a small isolated HRU-only run.

Files rewritten in the generated output folder:

• hru.con: keeps selected HRUs, renumbers HRU IDs from 1, remaps the props pointer, and sets the routing target count to 0.
• hru-data.hru: keeps the referenced HRU data rows and renumbers their first-column IDs from 1.
• ls_unit.ele: keeps landscape-unit elements for the selected HRUs and remaps their HRU pointers.
• ls_unit.def: keeps landscape-unit definitions that still reference retained elements.
• rout_unit.ele: keeps routing-unit elements for the selected HRUs and remaps their HRU pointers.
• rout_unit.def: keeps routing-unit definitions that still reference retained route elements.
• rout_unit.rtu: keeps routing-unit data rows that still match retained routing-unit definitions.
• object.cnt: sets the object total to the selected HRU count and zeros the other supported object counts.
• file.cio: replaces routed and non-HRU connection filenames with null, including routing units, channels, aquifers, reservoirs, recalls, outlets, delratio, water allocation, object print, HRU-LTE, and related connection files.
• print.prt: disables routing-unit and landscape-unit print rows that are not valid after routing is removed: lsunit_wb, lsunit_nb, lsunit_ls, lsunit_pw, ru, ru_salt, and ru_cs.

Routed Mode

Turn on Keep Routing to preserve the downstream routing chain from the selected HRUs.

The tool finds the routing units containing the selected HRUs, traces downstream through the SWAT+ connectivity graph, keeps every reachable object, filters those files, and renumbers IDs so SWAT+ arrays still line up.

Files that can be rewritten when their object type is kept:

• hru.con and hru-data.hru
• rout_unit.con and rout_unit.rtu
• chandeg.con and channel-lte.cha
• channel.con and channel.cha
• aquifer.con and aquifer.aqu
• reservoir.con and reservoir.res
• recall.con and recall.rec
• exco.con
• delratio.con
• outlet.con
• rout_unit.ele
• rout_unit.def
• ls_unit.ele
• ls_unit.def
• object.cnt
• file.cio

In routed mode, file.cio keeps connection and data files for retained object types and sets unneeded object types to null. It always nullifies water_allocation.wro, element.wro, water_rights.wro, and object.prt for subset runs.

Routed mode does not disable the routing-unit rows in print.prt; those outputs remain available because routing units are still present.

Running From The Exe

The current packaged executable is:

dist\swat_processor\swat_processor.exe

Use the GUI to:

1. Select the source TxtInOut directory.
2. Enter one HRU ID or enable Multiple HRUs and enter values such as 1,4-6,10.
3. Leave Keep Routing off for isolated HRU mode, or turn it on for routed mode.
4. Turn on Run SWAT+ Simulation only when you want the generated folder to run immediately.
5. Click Modify HRU.

If simulation is enabled and more than one .exe is found in the source directory, the GUI asks which executable to run.

Running From Source

Install dependencies:

py -3.12 -m pip install -r requirements.txt

Run the GUI:

py -3.12 SRC\gui\gui_main.py

Run the test suite:

py -3.12 -m pytest tests -q

Build the Windows executable:

$env:PYTHONPATH=''
py -3.12 -m PyInstaller --noconfirm --clean gui_main.spec

Core Modules

• SRC/core/swat_main.py: main processing entry point.
• SRC/core/FileModifier.py: isolated-mode file rewrites.
• SRC/core/RoutingTracer.py: routed-mode tracing, filtering, and renumbering.
• SRC/core/object_counts.py: header-aware object.cnt count updates.
• SRC/core/TxtinoutReader.py: TxtInOut copy and SWAT+ execution support.
• SRC/core/FileReader.py: SWAT+ table reading helper.
• SRC/gui/gui_logic.py: GUI controller.
• SRC/gui/gui_layout.py: GUI layout.

Important Notes

The source TxtInOut files are not rewritten directly. The generated solo_* or multi_* folder is the working copy that changes.

Routed mode is only as complete as the connectivity files in the source TxtInOut folder. If a selected HRU routes to object types that are missing from the source, those missing files cannot be reconstructed.

Generated simulation outputs can be large and are ignored by git.