StormSewer manual

StormSewer is a free, GPL-licensed editor for EPA SWMM 5 models, with a storm-sewer design tool (Rational method, Manning, standard-step HGL, HEC-22 inlets, auto-sizing) built in. It draws the model on a map, edits it in a property sheet and attribute tables, runs it on the unmodified EPA engine you already have installed, and brings the results back onto the same map.

This manual is written for the engineer who has to defend the numbers. Every claim in it can be checked against the source code, and where the software does not do something yet, the manual says so.

Contents

Part 1 — Start here

• 1. Start here — install, open a model in fifteen minutes, the workspace tour, undo, saving, and what "lossless" means.

Part 2 — Tutorials

• 2. Tutorials — ten cumulative exercises on the EPA Detention Pond model: draw a network, add subcatchments and a rain gage, build a design storm, run and read the status, profile, results on the map, plots and tables, storm-sewer design and auto-size, compare two runs, the model report, and the Python terminal.

Part 3 — Panes and tools

• 3. Map and tools
• 4. Project browser
• 5. Property sheet
• 6. Attribute tables
• 7. Layers
• 8. Project dialogs
• 9. Run and engines
• 10. Results views
• 11. Profile
• 12. Storm-sewer design panel
• 13. Import and export
• 14. Preferences

Part 4 — Methods

• 15. Methods — what StormSewer computes itself, with equations and citations, and what it leaves to the SWMM engine.

Part 5 — Troubleshooting

• 16. Troubleshooting — continuity error, silent failures, instability, surcharge versus flooding, offsets, units, width, ERROR 209/335/363, hotstart, missing coordinates, non-ASCII paths, engine versions.

Part 6 — File formats

• 17. File formats — .inp section by section (including the ones EPA's Appendix D omits), what StormSewer preserves, .out, .rpt, .ssproj, CSV, GeoJSON, world files.

Part 7 — Python

• 18. Python terminal cookbook — the bound model, out and rpt names and ten recipes.

Appendices

• A. Keyboard shortcuts
• B. Menu reference
• C. Error codes
• D. Glossary
• E. Credits and licences

Conventions

• Menu paths are written File → Open .inp….
• Keys are written Ctrl+Z. Single letters such as J are tool shortcuts and work only when no text field has the keyboard.
• "The engine" means the EPA SWMM executable (runswmm.exe or runswmm) that StormSewer runs as a child process. StormSewer never modifies it.
• Where the manual cites the SWMM manuals it uses these abbreviations: UM — Storm Water Management Model User's Manual Version 5.2 (EPA/600/R-22/030); RM I — Reference Manual Volume I, Hydrology (EPA/600/R-15/162A); RM II — Reference Manual Volume II, Hydraulics (EPA/600/R-17/111); HEC-22 — FHWA Urban Drainage Design Manual, Hydraulic Engineering Circular 22, 3rd edition (FHWA-NHI-10-009). All four are public documents.

Versions

This manual describes StormSewer 0.9.8 and was checked against EPA SWMM 5.2.4. The tutorial datasets are in docs/datasets/; they are the EPA sample models and are public domain.