SWMM Engineering Handbook
SWMM Engineering Handbook
A handbook of SWMM, InfoSWMM, InfoSewer, ICM, hydrology, hydraulics, and solver practice.
The front door to SWMMFive: a curated guide to hydrology, hydraulics, solvers, tools, and historical notes for urban drainage modelers. Pick a starting path below, or browse the handbook chapters. (This site is independent and not associated with the EPA.)
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Handbook chapters
1 · Fundamentals
What SWMM is, nodes & links, and the model data structure.
2 · Hydrology
Rainfall–runoff, infiltration, RDII, and LID.
3 · Hydraulics
Flow routing, capacity, and the hydraulic grade line.
4 · Dynamic Wave & St. Venant
How SWMM solves unsteady flow — and how the solvers differ.
5 · Structures & Controls
Pumps, storage, force mains, and real-time control.
6 · InfoSWMM / InfoSewer
The ArcGIS-era engines and their SWMM5 lineage.
7 · ICM & 2D
InfoWorks ICM, the SWMM engine inside ICM, and 1D–2D coupling.
8 · History & Code
SWMM3/4 lineage, SWMM5 internals, and the road to SWMM 6.
Featured references
The full engine error-number reference — the most-visited page on the site.
Step-by-step of how SWMM computes orifice and weir discharge.
SWMM 4 vs SWMM 5 solution schemes, side by side.
Tools & external resources
Recent updates
SWMM Engineering Handbook
This page is the front door to SWMMFive — a curated index into 1,000+ posts on SWMM, InfoSWMM, ICM, and solver practice.
- Pick a Start here path based on who you are
- Jump into any of the 8 handbook chapters
- Open the most-used featured references and tools