OpenSWMM Manuals

The following manuals document the use, application, and technical reference for OpenSWMM, the next generation of the EPA Storm Water Management Model. These manuals build on the original EPA SWMM documentation, updated and extended for OpenSWMM.

See Authors & Contributors for the full list of authors and contributors.

Engine Manual (OpenSWMM Engine Manual) — the objects a model is built from, the input file format, the files the engine reads and writes, its reports, the C and Python interfaces, and every error and warning message.
GUI Manual — the graphical application, SWMMVis, is documented separately at https://www.hydrocouple.org/openswmm.gui/
Application Manual (OpenSWMM Application Manual) — which formulation to use and what changes if you pick another: six decision workflows and thirteen chapters, each worked from a deck in the repository with every figure generated from its runs.
Reference Manuals — the theory and numerics behind each formulation, with the status of each alternative marked Implemented, Experimental, Planned or Retired.
- Hydrology Reference Manual (OpenSWMM Hydrology Reference Manual) — meteorology, runoff, infiltration, groundwater, snowmelt, RDII, and the distributed surface and subsurface processes on the 2D mesh.
- Hydraulics Reference Manual (OpenSWMM Hydraulics Reference Manual) — the four flow routers, pressurisation, cross-sections, pumps and regulators, the explicit finite-volume solver and two-dimensional overland flow.
- Quality Reference Manual (OpenSWMM Water Quality Reference Manual) — buildup, washoff, treatment, LID controls, the three transport engines, multi-species reactions, water age and heat, and surface quality on the mesh.
C API Reference
- The OpenSWMM Engine v6 C API is organized by domain into 31 public headers. See the Modules page for the full API reference generated from the include/openswmm/engine/ headers.
- Start with openswmm_engine.h for the engine lifecycle, then explore domain-specific headers such as openswmm_nodes.h, openswmm_links.h, and openswmm_model.h.
Changelog — see CHANGELOG.md for the complete list of changes in each release.