An App for People Who Have Been Seeing the SWMM5 Report file for 1 - 50 Years
](https://www.linkedin.com/in/robertdickinson/)
Helping across the full stormwater spectrum: SWMM (50+ yrs), InfoSWMM/ESRI (20 yrs), InfoWorks ICM (15 yrs), & Autodesk AEC Collection (5 yrs) Grandpa (10 yrs)
November 30, 2025
As I mentioned in previous articles, I like the Vibe coding revolution and make a lot of apps that help me or fix a many-decades-long pain point. The main point is that this helps me, and maybe it helps you or at least interests you. Now, what was the pain point? In 1980 I started using Extran 3 with punch cards and voluminous printouts. No monitors and no PCs yet. The problem was reading through the printout to see if there were any model problems. Extran 3 and Extran 4 later become part of SWMM5 as the Dynamic Wave Solution, and the rpt file of SWMM5 has a lot of features or tables from Extran 3.
This app loads the RPT file and tells you if there are any unstable links or nodes that have continuity errors. I know that is already in the tables but in my experience a few people do now know how to read them.
This is what the simple REPLIT app does: you pick an RPT file, and it reads the file and extracts the information in maybe a better fashion. It is free and open source (you can read and see the code if you want in the DOCS session). It even has a Nano Banana output box that you can use to make a graphic.
Nano Banana Prompt for the App.
Simple UX—Just pick an RPT file.
What You're Actually Seeing in the App
The app name is "Surcharge Detective it's really an Instability & Continuity Error Diagnostic Tool. The surcharge detection (Max/Full Depth > 1.0) is one output among several. It is a RPT file diagnostic dashboard.
The Output Table Dashboard
The DOCS tab has a nice explanation of the flow instability index.
Where is the App?
Thanks for reading, and I hope you like using the App.
Obvious Future Work - Add the ability to read all RPT files in a Directory or Subfolders
I need this as I have thousands of SWMM5 models and RPT files