Real
Rainfall, terrain, land cover, soil, and — in the eight cities — the pipe network itself come straight from published data.
Data
Built entirely from free and open data
Every layer of a SWMMCanada model traces back to a public Canadian or global dataset — no licensed data, no manual downloads. Here is what goes in, and what each source provides.
The datasets
| Model layer | Source | What it provides |
|---|---|---|
| Rainfall & temperature | ECCC historical climate data | Observed precipitation and temperature time series for your simulation window; temperature also enables snowmelt in the model. |
| Design storms | ECCC IDF curves | Real intensity–duration–frequency values used to size synthesized pipes with the rational method. |
| Terrain | NRCan MRDEM + HRDEM LiDAR | Elevation for subcatchment delineation and slopes — 1 m LiDAR is selected automatically where available. |
| Land cover | NALCMS | Imperviousness and land-use parameters for each subcatchment. |
| Soil | SoilGrids | Soil properties behind the infiltration parameters. |
| Streets | OpenStreetMap | The street graph that network synthesis follows outside the eight real-network cities. |
| Storm & sanitary networks | 8 municipal open-data portals | Real pipes, inverts, diameters, manholes, and outfalls in Victoria, Ottawa, Calgary, Surrey, London, Kitchener–Waterloo, Kelowna, and Regina — plus parcels where published. |
| Streamflow | ECCC HYDAT | Observed flows for downstream validation and calibration. |
The full list — with links, licences, and exactly how each dataset is used — lives in DATA.md in the repository.
Transparency
What's real, derived, or approximated
Derived
Subcatchment boundaries, slopes, imperviousness, and infiltration parameters are computed from those datasets with documented methods.
Approximated
Rainfall losses, roughness, and curve numbers are first-pass estimates. Every approximation is called out in ASSUMPTIONS.md, layer by layer.
Validated against real cities
Real-city validation runs, figures, and the EPA SWMM numbers are published in RESULTS.md — including network fidelity checks against the eight municipal datasets.
