Causeway Flow
Commercial
Storm and foul water drainage design and 1D hydraulic modelling software for UK and Irish civil engineers.
EPA National Stormwater Calculator
StableEPA's free tool for estimating site runoff reduction from green infrastructure, with climate scenarios.
by US EPA
- Pricing
- Gov-Public
- License
- US Government (public domain)
- Commercial use
- Permitted
- Ecosystem
- SWMM
- Platform
- Web, Windows
About EPA National Stormwater Calculator
The National Stormwater Calculator estimates annual runoff, retention and frequency statistics for a site under different green-infrastructure choices — rain gardens, permeable pavement, cisterns, disconnection — using the SWMM engine underneath, US soils and rainfall data built in, and optional future-climate scenarios.
It targets the early planning conversation: what LID mix gets a site to a retention target, before anyone builds a full model. US-centric by data but conceptually portable, and its SWMM underpinnings mean results transfer credibly into detailed design.
Where it fits in the workflow
TerrainCatchmentRainfallRunoffRoutingHydraulicsMappingReporting
Appears in collections
- The Free Drainage Engineer's Toolkit
Zero-budget, reviewer-accepted tools for everyday stormwater and drainage design.
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Ranked by the topics, categories and workflow stages they share with EPA National Stormwater Calculator.
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