National Stormwater Calculator FAQs
Frequently Asked Questions
This page provides some frequently asked questions related to EPA's National Stormwater Calculator.
1. Can users utilize the SWC for project sites located outside of the U.S.? No, it is only for projects located in the U.S. Some projects located in Canada or Mexico that border the U.S. may be able to use data from the SWC if site conditions are similar to those in the U.S. The SWC is not intended for international applications. Users may use the Storm Water Management Model (SWMM) for international applications.
2. Can a user utilize weather data external to the SWC, such as user supplied weather data? No
3. Can a user utilize soils data external to the SWC, such as local soils data supplied by the user? No, but the user may use local soils data to manually select soil attributes within the SWC that reflect the conditions of local soils data that a user may like to use.
4. Is the SWC able to model Best Management Practices (BMP) treatment trains? No, a user would need to use the full SWMM model to conduct such modeling.
5. Are there any training materials or webinars on how to use the SWC? Yes, there are training materials from past webinars and conference presentations on the SWC available in EPA’s Science Inventory. Users can also request future training webinars or presentations on the SWC.
6. Where can a user access the software code for the SWC? The software code for the SWC may be found at in GitHub.