14. Preferences

AquaSWMM keeps a small preferences file per user: %APPDATA%\AquaSWMM\app_prefs.json on Windows, ~/Library/Application Support/AquaSWMM/app_prefs.json on macOS, $XDG_CONFIG_HOME/stormsewer/app_prefs.json (or ~/.config/aquaswmm/) on Linux. It is JSON with defaults for every key, so deleting it resets everything and an older file still loads. Nothing about a model is stored in it.

14.1 What is saved

Setting Where you set it Key
Theme — Dark, Light, or the system's View → Dark theme / Light theme theme
SWMM layer settings — per-kind visibility, labels, symbol size and colour, arrows, grid, underlay opacity, results overlay Layers tab (chapter 7) swmm_layers
Snap grid spacing for the storm-sewer plan storm-sewer workspace snap_grid_ft
Analyse automatically after an edit (storm-sewer workspace) storm-sewer workspace auto_analyze
Show the quick-start on launch; the interactive tutorial's "Don't show on startup" Help → Interactive Tutorial show_quick_start, tutorial_done
Draw zero-area catchments (storm-sewer workspace) storm-sewer workspace draw_zero_area
The free releases' support-reminder opt-out and last-shown time (kept so their settings load; this version shows no reminder) — coffee_optout, coffee_last_epoch

The SWMM workspace's grid-snap spacing, object snap and the View-menu toggles (labels, arrows, grid) are per session and start from their defaults each launch; the Layers tab's copies of arrows and grid are the persisted ones.

Beside it: recent.json (storm-sewer projects) and recent-inp.json (SWMM models), eight entries each, most recent first.

14.2 Environment variables

Variable Effect
AQUASWMM_SWMM_ENGINE_DIR A folder searched first for runswmm (§1.2).
AQUASWMM_ALR_SCRIPT, AQUASWMM_ALR_PYTHON Where ALR's run_headless_swmm.py is, and which interpreter runs it (§9.5).
AQUASWMM_SOFTWARE_GL=1 Windows: skip the hardware renderers and start on the bundled Mesa software OpenGL.

Every AQUASWMM_* variable is also read under its pre-0.11 name, STORMSEWER_*, so a login script written for an older release keeps working. Where both are set, the AQUASWMM_ one wins.

14.3 Command line

AquaSWMM [file]            open a .inp, .ssproj, .stm, .xml (LandXML) or .dxf
AquaSWMM --check-renderer  start, draw one frame, report the renderer, exit
AquaSWMM --version
AquaSWMM --help

A .inp opens in the SWMM workspace; the others open in the storm-sewer workspace.